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  • 1990-1994  (112)
  • 1955-1959  (4)
  • 1890-1899
  • 1800-1809
  • Brassica napus
  • 1
    ISSN: 1432-203X
    Keywords: Agrobacterium rhizogenes ; Brassica napus ; glutamine synthetase ; phosphinothricin ; rape ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hairy roots of Brassica napus (rape cv. Giant) have been produced that contain the cytosolic glutamine synthetase (GS) gene from Glycine max (soybean). Leaf explants were cocultivated with Agrobacterium rhizogenes strain A4T harbouring the binary vector pLN16. This vector was constructed by inserting a soybean cytosolic GS cDNA into the multiple cloning site of pGA643, placing it under the control of the CaMV promoter. In addition, the T-DNA region of pLN16 contained a NPTII gene for selection of transformed cells. Transgenic hairy roots grew prolifically on hormone-free media containing a selective level of kanamycin. Southern and northern analyses confirmed the presence of soybean GS DNA and transcripts, respectively. These transformed hairy roots also have a greater abundance of the GS polypeptide, approximately 3–6 fold greater GS activity and lower levels of endogenous ammonia. Hairy roots provide a useful system for studying responses to phosphinothricin (PPT). Hairy roots grown in media containing PPT had lower GS activity, greater ammonia accumulation and slower growth than controls. The presence of the soybean GS gene in the hairy roots reduced these PPT-induced effects and resulted in higher GS activity, lower ammonia levels and faster growth than in PPT-treated controls. Greater tolerance of PPT was also seen in shoots regenerated from the hairy roots displaying elevated levels of GS activity.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 87 (1994), S. 697-704 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Cultivar identification ; RAPDs ; Rapeseed ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RAPDs (Randomly Amplified Polymorphic DNAs) were used to discriminate among 23 cultivars of oilseed rape (Brassica napus) selected from several breeding programs. A set of 100 random sequence 10-mer primers were tested, of which 70 produced bands and 22 showed evidence of polymorphism. A selection of six primers produced 23 polymorphic bands of between 300 to 2200 base pairs in size, sufficient to distinguish between the cultivars. An analysis of seed of five cultivars obtained from four different sites showed stability of banding pattern over source of seed. The analysis was repeated using four different thermocyclers, each of which produced the same band pattern. UPGMA cluster analysis indicates that the relationships among some of the cultivars is closer for those from the same breeding program than for those from different programs. The results of this study show that RAPDs can be used as a method of identification for oilseed rape cultivars.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 88 (1994), S. 321-323 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Inbreeding ; Inbreeding depression ; Line variation ; Competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rapeseed plants, of the summer annual variety Topas, that had been selfed twice consecutively were compared to outcrossed half-sibs for inbreeding depression in a rapeseed population at mating equilibrium. The effect of dominance-suppression competition was included in the effect of inbreeding. Both female-and male-fitness characters showed significant inbreeding depression. Biomass decreased 17% with inbreeding and was highly correlated with seed weight. The total number of flowers decreased 15% with inbreeding. There was a significant effect of lines. The possible importance of experimental design in studies that estimate inbreeding depression is discussed.
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  • 4
    ISSN: 1432-2242
    Keywords: Brassica napus ; Raphanus sativus ; Ogura cytoplasmic male-sterility restorer gene ; Bulked segregant analysis ; RAPD markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bulked segregant analysis was employed to identify random amplified polymorphic DNA (RAPD) markers linked to the restorer gene (Rfo) used in theOgura radish cytoplasmic male sterility of rapeseed. A total of 138 arbitrary 10-mer oligonucleotide primers were screened on the DNA of three pairs of bulks, each bulk corresponding to homozygous restored and male sterile plants of three segregating populations. Six primers produced repeatable polymorphisms between paired bulks. DNA from individual plants of each bulk was then used as a template for amplification with these six primers. DNA polymorphisms generated by four of these primers were found to be completely linked to the restorer gene with the polymorphic DNA fragments being associated either with the fertility restorer allele or with the sterility maintainer allele. Pairwise cross-hybridization demonstrated that the four polymorphic DNA fragments did not share any homology. Southern hybridization of labelled RAPD fragments on digested genomic DNA from the same three pairs of bulks revealed fragments specific to either the male sterile bulks or to the restored bulks and a few fragments common to all bulks, indicating that the amplified sequences are low copy. The four RAPD fragments that were completely linked to the restorer locus have been cloned and sequenced to develop sequence characterized amplified regions (SCARs). This will facilitate the construction of restorer lines used in breeding programs and is the first step towards map-based cloning of the fertility restorer allele.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 88 (1994), S. 123-128 
    ISSN: 1432-2242
    Keywords: Brassica napus ; RFLP markers ; RAPD markers ; Genetic distance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RFLP and RAPD markers were evaluated and compared for their ability to determine genetic relationships in a set of three B. napus breeding lines. Using a total of 50 RFLP and 92 RAPD markers, the relatedness between the lines was determined. In total, the RFLP and the RAPD analysis revealed more than 500 and 400 bands, respectively. The relative frequencies of loci with allele differences were estimated from the band data. The RFLP and RAPD marker sets detected very similar relationships among the three lines, consistent with known pedigree data. Bootstrap analyses showed that the use of approximately 30 probes or primers would have been sufficient to achieve these relationships. This indicates that RAPD markers have the same resolving power as RFLP markers when used on exactly the same set of B. napus genotypes. Since RAPD markers are easier and quicker to use, these markers may be preferred in applications where the relationships between closely-related breeding lines are of interest. The use of RAPD markers in fingerprinting applications may, however, not be warranted, and this is discussed in relation to the reliability of RAPD markers.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 89 (1994), S. 540-544 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Crossability ; Cytogenetics ; Intergeneric hybridization ; Sinapis pubescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cytological possibility of gene transfer from Sinapis pubescens to Brassica napus was investigated. Intergeneric hybrids between Brassica napus (2n = 38) and Sinapis pubescens (2n = 18) were produced through ovary culture. The F1 hybrids were dihaploid and the chromosome configurations were (0–1) III + (2–11) II + (5–24) I . One F2 plant with 38 chromosomes was obtained from open pollination of the F1 hybrid. Thirty-one seeds were obtained from the backcross of the F2 plant with B. napus. Five out of seven plants had 38 chromosomes, and the pollen stainability ranged from 0% to 81.4%. In the B2 plants obtained from the backcross of B1 plants with B. napus, 66.7% of the plants examined had 38 chromosomes. S. pubescens may become a gene source for the improvement of B. napus.
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  • 7
    ISSN: 1432-203X
    Keywords: Ammonia ; Agrobacterium rhizogenes ; Brassica napus ; glutamine ; glutamine synthetase ; phosphinothricin ; rape
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hairy roots of Brassica napus (rape cv. Giant) were produced by cocultivating leaf and cotyledon explants with Agrobacterium rhizogenes strain A4T. The hairy roots grew prolifically on solid and in liquid media. Incorporation of ammonium sulphate or phosphinothricin (PPT) into the media reduced growth. PPT treatment reduced glutamine synthetase (GS) activity and increased the ammonia content of the hairy roots. We have found that PPT treatment also induces a loss of glutamine from the roots and this may influence root growth. To test this we grew hairy roots in a liquid medium containing 10 mM glutamine. This glutamine treatment overcame the PPT induced suppression of growth but also significantly increased GS activity, reduced ammonia accumulation and increased the levels of glutamate and asparagine.
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  • 8
    ISSN: 1573-5087
    Keywords: abscisic acid ; 1-aminocyclopropane-1-carboxylic acid ; BAS 111..W ; Brassica napus ; cytokinins ; oilseed rape ; pod ; senescence ; triazole growth retardant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Foliar treatment of oilseed rape plants (Brassica napus L.ssp. napus cv. Linetta) with the growth retardant BAS 111..W at the 5th leaf stage delayed pod senescence during early maturation. Changes of immunoreactive cytokinin- and abscisic acid (ABA)- like substances and of the ethylene precursor 1-aminocyclo-propane-1-carboxylic acid (ACC) and its malonyl-conjugate (MACC) were determined in intact whole pods. When compared with control plants, higher levels of total chlorophyll correlated with four-fold and three-fold increases of trans-zeatin riboside- and dihydrozeatin riboside-type cytokinins, respectively, in the pods of plants treated with 0.25 mg BAS 111..W per plant. Isopentenyladenosine-type cytokinins and ACC and MACC contents remained virtually unchanged, whereas ABA levels dropped considerably below those of controls (60% reduction). However, when analysed at late pod maturity, BAS 111..W treatment no longer affected the total chlorophyll content, or the levels of cytokinins, ABA, ACC and MACC. We hypothesize that the retardant-induced changes in the hormonal status of the pods, favouring the senescence-delaying cytokinins as opposed to abscisic acid, could contribute to the developmental delay.
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  • 9
    ISSN: 1573-5028
    Keywords: abscisic acid ; ABA-response element ; bi-directional promoter ; Brassica napus ; oleosin ; seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Brassica napus, oleosins are expressed at high levels in the seed during the latter stages of embryo development. The cis-acting regulatory properties of an 872 bp promoter fragment of a B. napus oleosin gene were examined by analysis of β-glucuronidase (GUS) expression in transgenic tobacco plants containing an oleosin promoter-GUS transcriptional fusion. The reporter gene was expressed at high levels only in seeds, specifically in embryo and endosperm tissue and regulated throughout seed development. These data demonstrate that oleosin gene transcription is regulated in a tissue-specific and temporally regulated manner and clearly indicate that oleosin protein expression is co-ordinated primarily at the transcriptional level. Oleosin mRNA was shown to be abscisic acid (ABA) inducible and an ABA-response element in the oleosin promoter was shown to be bound by a protein factor in a sequence-specific manner. Sequence analysis of the oleosin promoter has identified several other putative cis-acting sequences which may direct oleosin gene expression. The presence of a large open reading frame in the bottom strand of the oleosin promoter (ORF2) which encodes a polypeptide similar to the ethylene-induced E4 gene of tomato is reported. A PCR-generated DNA probe containing the ORF2 sequence hybridised with a 1.4 kb transcript in total RNA extracts of a variety of tissues, including leaves and germinated seed cotyledons. This finding suggests that the oleosin gene promoter directs transcription in both directions. It is the first report of a bi-directional nuclear gene promoter in plants.
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  • 10
    ISSN: 1573-5028
    Keywords: acyl-CoA-binding protein ; Brassica napus ; diazepam-binding inhibitor protein ; linkage map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA encoding an acyl-CoA-binding protein (ACBP) homologue has been cloned from a λgt11 library made from mRNA isolated from developing seeds of oilseed rape (Brassica napus L.). The derived amino acid sequence reveals a protein 92 amino acids in length which is highly conserved when compared with ACBP sequences from yeast, cow, man and fruit fly. Southern blot analysis ofBrassica napus genomic DNA revealed the presence of 6 genes, 3 derived from theBrassica rapa parent and 3 fromBrassica oleracea. Northern blot analysis showed that ACBP genes are expressed strongly in developing embryo, flowers and cotyledons of seedlings and to a lesser extent in leaves and roots.
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  • 11
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Brassica napus ; gene expression ; Nicotiana tabacum ; retrotransposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of the tobacco (Nicotiana tabacum) retrotransposon Tntl has previously been shown to be strongly regulated and driven from the 5′ long terminal repeat (LTR). We report here that the Tntl LTR can promote activity of the β-glucuronidase (GUS) reporter gene in two heterologous species of the Brassicaceae family, namely rapessed (Brassica napus) and Arabidopsis thaliana. The translational LTR-GUS fusion was active in transient expression studies performed with tobacco and rapeseed protoplasts, indicating that the LTR sequences are recognized in heterologous species. Our results also showed that Tntl LTR-promoted GUS expression in transgenic Arabidopsis is strongly regulated, and that, in contrast to tobacco, hormonal activation plays a significant role in the expression of the Tntl LTR in Arabidopsis. LTR sequences were shown to be more effective than the CaMV 35S enhancer region in transient expression studies performed with tobacco or rapessed protoplasts; and substitution of the LTR sequences upstream from the major transcriptional start with the CaMV 35S enhancer region gave high levels of expression in transgenic tobacco and Arabidopsis leaves, suggesting that a Tntl element with similar substitutions in its 5′ LTR might be suited for gene-tagging experiments in heterologous species.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 26 (1994), S. 1217-1222 
    ISSN: 1573-5028
    Keywords: Brassica napus ; pistil ; stigma ; cDNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A partial cDNA clone, Pis 63, corresponding to a mRNA highly expressed in Brassica napus pistils, was isolated by differential screening. PCR was used to complete the Pis 63 sequence (Pis 63-1) and to obtain the sequence of another related cDNA (Pis 63-2). Northern blot and in situ analyses demonstrated that these transcripts are expressed in the stigma throughout flower development. Pis 63-1 and Pis 63-2 display similarity to a cotton fibre cDNA clone.
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  • 13
    ISSN: 1573-5028
    Keywords: Brassica napus ; heterologous expression ; Rab/Ypt family ; small GTP-binding protein ; vesicular transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone (bra) encoding a small GTP-binding protein was isolated from Brassica napus by screening a root cDNA library with a degenerate oligonucleotide probe that corresponds to a highly conserved GTP-binding domain of the Ras superfamily. Sequence analysis shows that the clone contains an open reading frame of 219 amino acid residues with the estimated molecular mass of 24379 Da and this coding region contains all the conserved motifs of the Ras superfamily. The deduced amino acid sequence of the bra gene is most closely related to the Ypt/Rab family that functions in the vesicular transport (46% and 47% amino acid identity to the yeast Ypt1 and to the human Rab1, respectively) and is more distantly related to the other Ras-related families. The protein encoded by the bra gene, when expressed in Escherichia coli, shows the ability to bind GTP. Furthermore, when the bra gene is introduced into Saccharomyces cerevisiae under the regulation of the yeast GAL1 promoter, the gene can complement the temperature-sensitive yeast mutation ypt1-1 that has defects in vesicular transport function. The amino acid sequence similarity and the functional complementation of the yeast mutation suggest that this gene is likely to be involved in the vesicular transport in plants. Genomic Southern analysis shows that this gene is a member of a small gene family in Brassica napus.
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  • 14
    ISSN: 1573-5060
    Keywords: Brassica napus ; microspore culture ; colchicine treatment ; chromosome doubling ; DH-breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of colchicine on isolated microspore cultures of Brassica napus was evaluated in order to combine a positive effect of colchicine on the induction of embryogenesis with the possibility to induce chromosome doubling at an early developmental stage, thus avoiding the production of haploid or chimeric plants. Colchicine was added to the culture medium immediately after isolation of B. napus microspores. The cultures were incubated from 6 to 72 h with various concentrations of colchicine. Samples were taken from the regenerating embryoids after 6 weeks for ploidy determination by flow-cytometry. The highest diploidization rate was obtained after a 24 h treatment of microspores with 50 mg/l colchicine, leading to 80–90% diploid embroids. A concentration of 100 mg/l colchicine applied for the same duration resulted in a lower diploidization rate (76–80%). Treatment durations of 6 h were not long enough to induce a high rate of diploidization, whereas the application of 10 mg/l for 72 h was also very effective. A sample of the plants regenerated from the colchicine treated microspores was transferred to the greenhouse. The plants looked similar to normal diploid rapeseed plants and showed reasonable pod and seed set. Thus, an additional generation for seed increase in the greenhouse is rendered unnecessary. The advantage of applying a minimum volume of colchicine under controlled in vitro conditions means a considerable saving of time and labour in DH-breeding programs.
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  • 15
    ISSN: 1573-5060
    Keywords: Brassica napus ; light reflectance ; seed colour ; NIR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Improved oil, protein and fibre contents are associated with light seed colour in rapeseed but the lack of reliable and efficient methods to measure seed colour has hindered breeding efforts for this trait. The feasibility of using light reflectance to assess seed colour in Brassica napus was examined using scanning light reflectance spectrophotometry and near infrared reflectance (NIR). Light reflectance by seed samples from 30 doubled haploid (DH) lines segregating for seed colour increased as the wavelength of the illuminating light in the scanning spectrophotometer increased between 550 and 650 nm. The largest reflectance values were measured for the yellow seed samples; the brown seed samples were intermediate and the black seed samples had the lowest reflectance values. The areas under the reflectance curves were used to transform the spectra to single values. Average light reflectance area values for the seed colour classes were significantly different from each other. The DHs and their corresponding light reflectance area values were also used to calibrate a NIR analyzer modified with 670 and 710 nm filters. The best calibration curve used three wavelengths (670, 2190 and 2208 nm) and had a multiple correlation coefficient of 0.987. Light reflectance area values determined with the calibrated NIR analyzer for 30 randomly selected breeding lines could be used to categorize the colour of the seed samples with no discrepancies between the visual and instrument classifications. The results indicate that NIR can be used to assess seed colour in rapeseed.
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  • 16
    ISSN: 1573-5060
    Keywords: Brassica napus ; heterosis ; hybrid breeding ; oilseed rape ; self-incompatibility ; pollination control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Self-incompatibility was shown to be an effective method of pollination control in spring rapeseed (B. napus L. ssp. oleifera (Metzg.)) by comparing the yield of a Westar-Topas syn-1 produced by crossing two SI lines with the yield of the corresponding syn-1 produced by hand pollination. Although the trial showed high-parent heterosis in the syn-1s, there was insufficient replication to determine the level of heterosis.
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  • 17
    ISSN: 1573-5028
    Keywords: Brassica napus ; Enoyl-ACP reductase ; isoforms ; stearoyl-ACP desaturase ; developmental expression ; seed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of mRNA and the steady-state levels of two-component enzymes of plant fatty acid synthetase (FAS) were studied. Northern analysis of enoyl-ACP reductase (ER) and stearoyl-ACP desaturase (SD) gene expression showed that steady-state levels of both transcripts increase during lipid deposition in the seed reaching a maximum at 29 days after flowering (DAF). The steady-state level of ER message falls very quickly after reaching its maximum, whereas the SD message is longer-lived. The levels of these specific mRNAs in seed are 15–30 times greater than in leaf. Optimum mRNA expression precedes the maximum levels of synthesis of the two proteins, which in turn precede the maximum level of oil. The expression of isoenzymes of ER were examined by two-dimensional western blotting in both leaf and seed tissue. Four enzymes are expressed in both of these tissues; the two most abundant isoforms in seed material are also the most abundant in leaf tissue.
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  • 18
    ISSN: 1573-5028
    Keywords: anther ; antisense RNA ; Brassica napus ; male fertility ; tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An antisense approach was used to attempt to determine the function of the highly abundant, tapetum-specific A9 transcript in microsporogenesis. A Brassica napus A9 cDNA clone was linked in sense and antisense orientations to the Arabidopsis thaliana A9 promoter and the resulting chimaeric genes introduced into B. napus. A high proportion of the offspring of B. napus antisense A9 plants had very low or undetectable levels of A9 mRNA. However, these plants set seed and had pollen of normal or near normal viability. Therefore, under the conditions studied, the A9 protein appears not to be essential for male fertility in B. napus.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 24 (1994), S. 223-227 
    ISSN: 1573-5028
    Keywords: Brassica napus ; dehiscence ; dehydrogenase ; pod ; protochlorophyllide reductase ; shatter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dehiscence of oilseed rape pods, commonly known as pod shatter, is a process of agronomic importance that results in seed loss causing yield reductions and carry-over of the crop into the following growing season. In an effort to understand the mechanisms underlying this developmental event, the changes in gene expression that accompany pod shatter have been examined with a view to understanding how the process is regulated. In order to achieve this, a cDNA library was constructed using mRNA extracted from the dehiscence zone of developing pods. Differential screening with non-dehiscence zone cDNA led to the isolation of a pod-specific clone, SAC25, with a transcript size of 1100 nucleotide encoding a predicted polypeptide of 34 kDa. The level of SAC25 mRNA accumulation increased during pod development. The sequence shows no significant homology to others within the databases but has two identifiable amino acid motifs, one is an adenine nucleotide binding site for NAD/FAD dehydrogenases and the other is a conserved feature of the ribitol dehydrogenase family. The amino acid sequence has four putative glycosylation sites and contains four cysteine residues. Genomic Southern analysis indicates that SAC25 may be encoded by a single gene or a small gene family. The function of this mRNA is unknown but possible roles in dehiscence and pod development are discussed.
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  • 20
    ISSN: 1573-5028
    Keywords: Brassica napus ; napin ; antisense ; seed storage protein ; seed storage lipid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To manipulate the quantity and quality of storage components in Brassica napus seeds, we have constructed an antisense gene for the storage protein napin. The antisense gene was driven by the 5′-flanking region of the B. napus napin gene to express antisense RNA in a seed-specific manner. Seeds of transgenic plants with antisense genes often contained reduced amounts of napin. In some transgenic plants, no accumulation of napin was observed. However, the total protein content of transgenic and wild-type seeds did not differ significantly. Seeds lacking napin accumulated 1.4 to 1.5 times more cruciferin than untransformed seeds, although the oleosin content was not affected. Fatty acid content and composition in the seeds of transgenic plants were also analyzed by gas chromatography. Though the total fatty acid content of the transformants was the same as that of non-transformants, there was a reduction in 18:1 contents and a concomitant increase of 18:2 in seeds with reduced napin levels. This observed change in fatty acid composition was inherited in the next generation.
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  • 21
    ISSN: 1573-5028
    Keywords: Brassica napus ; microspore embryogenesis ; napin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Brassica napus cv. Topas microspores can be diverted from pollen development toward haploid embryo formation in culture by subjecting them to a heat stress treatment. We show that this switch in developmental pathways is accompanied by the induction of high levels of napin seed storage protein gene expression. Changes in the plant growth or microspore culture conditions were not by themselves sufficient to induce napin gene expression. Specific members of the napin multigene family were cloned from a cDNA library prepared from microspores that had been induced to undergo embryogenesis. The majority of napin clones represented three members (BnmNAP2, BnmNAP3 and BnmNAP4) that, along with a previously isolated napin genomic clone (BngNAP1), constitute the highly conserved BnmNAP subfamily of napin genes. Both RNA gel blot analysis, using a subfamily-specific probe, and histochemical analysis of transgenic plants expressing a BngNAP1 promoter-β-glucuronidase gene fusion demonstrated that the BnmNAP subfamily is expressed in embryogenic microspores as well as during subsequent stages of microsporic embryo development.
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  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 88 (1994), S. 662-668 
    ISSN: 1432-2242
    Keywords: Oilseed rape ; Brassica napus ; Restriction fragment length polymorphism ; Genetic diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oilseed rape (Brassica napus) is an important oilseed crop worldwide. Cultivars have been developed for many growing regions, however little is known about genetic diversity inB. napus germ plasm. The purpose of the research presented here was to study the genetic diversity and relationships ofB. napus accessions using restriction fragment length polymorphisms (RFLPs). Eighty threeB. napus accessions were screened using 43 genomic DNA clones which revealed 161 polymorphic fragments. Each accession was uniquely identified by the markers with the exception of the near-isogenic cvs ‘Triton’ and ‘Tower’. The RFLP data were analyzed by cluster analysis of similarity coefficients and by principal component analysis. Overall, there were three major groups of cultivars. The first group included only spring accessions, the second mostly winter accessions and the third, rutabagas and oilseed rape accessions from China and Japan. These results indicate that withinB. napus, winter and spring cultivars represent genetically distinct groups. The grouping of accessions by cluster analysis was generally consistent with known pedigrees. This consistency included the grouping of lines derived both by backcrossing or self-pollination with their parents.
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  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 89 (1994), S. 615-621 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Doubled haploid ; Linkage map ; Restriction fragment length polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The combined use of doubled haploid lines and molecular markers can provide new genetic information for use in breeding programs. An F1-derived doubled haploid (DH) population of Brassica napus obtained from a cross between an annual canola cultivar (‘Stellar’) and a biennial rapeseed (‘Major’) was used to construct a linkage map of 132 restriction fragment length polymorphism loci. The marker loci were arranged into 22 linkage groups and six pairs of linked loci covering 1016 cM. The DH map was compared to a partial map constructed with a common set of markers for an F2 population derived from the same F1 plant, and the overall maps were not significantly different. Comparisons of maps in Brassica species suggest that less recombination occurs in B. napus (n = 19) than expected from the combined map distances of the two hypothesized diploid progenitors, B. oleracea (n = 9) and B. rapa (n=10). A high percentage (32%) of segregating marker loci were duplicated in the DH map, and conserved linkage arrangements of some duplicated loci indicated possible intergenome homoeology in the amphidiploid or intragenome duplications from the diploid progenitors. Deviation from Mendelian segregation ratios (P 〈 0.05) was observed for 30% of the marker loci in the DH population and for 24% in the F2 population. Deviation towards each parent occurred at equal frequencies in both populations and marker loci that showed deviation clustered in specific linkage groups. The DH lines and molecular marker map generated for this study can be used to map loci for agronomic traits segregating in this population.
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  • 24
    ISSN: 1432-2242
    Keywords: Polymerase chain reaction ; Random amplified polymorphic DNA ; Self-incompatibility ; Brassica campestris ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have developed an efficient PCR-based system that uses RAPD markers for the certification of F1 hybrids of canola. These markers were selected by screening five parental lines used in three crosses X, Y and Z with 131, 131 and 322 primers respectively. Stable DNA fragments that were homozygous and specific to the male inbreds were used to certify F1 hybrid populations. The hybrid production system was based on self-incompatibility (SI) alleles that prevent self-pollination of the female parent. The efficiency of two S-alleles was compared under both field and greenhouse conditions. The percentage of hybridity was estimated in different F1 populations. We found a significant difference between the two alleles for their efficiency in controlling selfing; both alleles were stable under greenhouse conditions, one allele appeared less reliable under field conditions.
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  • 25
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    Transgenic research 3 (1994), S. 263-278 
    ISSN: 1573-9368
    Keywords: Brassica napus ; oilseed rape ; transgenic plants ; interspecific hybridization ; gene transfer ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Before novel transgenic plant genotypes are grown outside containment facilities and evaluated under field conditions, it is necessary to complete a risk assessment to consider the possible consequences of that release. An important aspect of risk assessment is to consider the likelihood and consequences of the transgene being transferred by cross-pollination to related species, including other crops, weeds and ruderal populations. The purpose of this report is to review the literature to assess the ease with whichBrassica napus can hybridize with related species. The evidence for hybridization is considered at three levels: a) by open pollination, b) by hand pollination and c) by the use ofin vitro ovule and embryo rescue techniques; and also examines the fertility and vigour of the F1, F2 and backcross generations. Four species are reported to hybridize withB. napus by open pollination:B. rapa andB. juncea using fully fertile parents; andB. adpressa andR. raphanistrum using a male-sterileB. napus parent. Seventeen species are reported to form hybrids (including the four species above) withB. napus when pollination is carried out manually. At least 12 of these species were unable to form F2 progeny, and eight were unable to produce progeny when the F1 was backcrossed to one of the parental species. Many factors will influence the success of hybridization under field conditions, including: distance between the parents, synchrony of flowering, method of pollen spread, specific parental genotypes used, direction of the cross and the environmental conditions. Even where there is a possibility of hybridization betweenB. napus and a related species growing in the vicinity of a release, poor vigour and high sterility in the hybrids will generally mean that hybrids and their progeny will not survive in either an agricultural or natural habitat.
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  • 26
    ISSN: 1573-9368
    Keywords: gene flow ; pollination ; bumblebees ; oilseed rape ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetically modified plants containing selectable markers offer a unique opportunity for pollination biologists to investigate some of the major, but intractable questions about paternity distributions and their causes. Here, a method is reported that uses transgenic plants to enable the quantification of the outcrossed fertilizations that result from a single pollinator visit. Gene flow mediated by worker bumblebees (Bombus terrestris) was studied among plants of oilseed rape (Brassica napus L. cv. Westar) where transgenic paternity in seeds of a non-transgenic plant was manifested as herbicide resistance. Overall, 91% of the resistant seeds resulted from the first four flowers that were visited after the bumblebee left the transgenic plant, and none was found beyond the 14th successively visited flower. The possibilities for developing the method to address various questions in pollination biology are discussed.
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  • 27
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    Protoplasma 183 (1994), S. 67-76 
    ISSN: 1615-6102
    Keywords: Actin microfilaments ; Brassica napus ; Cytochalasin D ; Pollen development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The organization of actin microfilaments (MFs) was studied during pollen development ofBrassica napus cv. Topas. Cells were prepared using three techniques and double labelled for fluorescence microscopy with rhodamine-labelled phalloidin for MFs and Hoechst 33258 for DNA. Microfilaments are present at all stages of pollen development with the exception of tricellular pollen just prior to anthesis. Unicellular microspores contain MFs which radiate from the surface of the nuclear envelope into the cytoplasm. During mitosis MFs form a network partially surrounding the mitotic apparatus and extend into the cytoplasm. Both cytoplasmic and phragmoplast-associated MFs are present during cytokinesis. Nuclear associated-, cytoplasmic, and randomly oriented cortical MFs appear in the vegetative cell of the bicellular microspore. Cortical MFs in the vegetative cell organize into parallel MF bundles (MFBs) aligned transverse to the furrows. The MFBs disappear prior to microspore elongation. At anthesis MFs are restricted to the cortical areas subjacent to the furrows of the vegetative cell. The use of cytochalasin D to disrupt MF function resulted in: (1) displacement of the acentric nucleus in the unicellular microspore; (2) displacement of the spindle apparatus in the mitotic cell; (3) symmetrical growth of the bicellular microspore rather than elongation and (4) inhibition of pollen tube germination in the mature pollen grain. This suggests that MFs play an important role in anchoring the nucleus in the unicellular microspore as well as the spindle apparatus during microspore mitosis, in microspore shape determination and in pollen tube germination.
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  • 28
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    Sexual plant reproduction 6 (1993), S. 52-56 
    ISSN: 1432-2145
    Keywords: In vitro culture ; Brassica napus ; Pollination ; Pod ; Seed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A technique for cultivating isolated flowers of Brassica napus has been developed. Flowers were harvested at anthesis, the surface of their peduncles was then sterilized and they were cultivated in a hormonefree medium. We used an MS medium supplemented with 3% sucrose as a source of organic carbon. From our experiments, it was concluded that no exogenous growth regulator is required to ensure normal growth and development in vitro. The flowers, and thereafter the pods, can be kept in culture until seed maturity. After 30 days, seed development resulted in three types of seeds: (1) normal, (2) milky and (3) aborted. The results show that the number of seeds per pod was not dependent on the order of flowers on the raceme (except the first 10 flowers and flowers above row 50). Our study supports the validity of this model as an easy tool for studying pollination and early seed development.
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  • 29
    ISSN: 1432-2242
    Keywords: Brassica napus ; BrdU ; Embryogenesis ; Microspore and pollen culture ; DNA synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The dynamics of nuclear DNA synthesis were analysed in isolated microspores and pollen of Brassica napus that were induced to form embryos. DNA synthesis was visualized by the immunocytochemical labelling of incorporated Bromodeoxyuridine (BrdU), applied continuously or as a pulse during the first 24 h of culture under embryogenic (32 °C) and non-embryogenic (18 °C) conditions. Total DNA content of the nuclei was determined by microspectrophotometry. At the moment of isolation, microspore nuclei and nuclei of generative cells were at the G1, S or G2 phase. Vegetative nuclei of pollen were always in G1 at the onset of culture. When microspores were cultured at 18 °C, they followed the normal gametophytic development; when cultured at 32 °C, they divided symmetrically and became embryogenic or continued gametophytic development. Because the two nuclei of the symmetrically divided microspores were either both labelled with BrdU or not labelled at all, we concluded that microspores are inducible to form embryos from the G1 until the G2 phase. When bicellular pollen were cultured at 18 °C, they exhibited labelling exclusively in generative nuclei. This is comparable to the gametophytic development that occurs in vivo. Early bicellular pollen cultured at 32 °C, however, also exhibited replication in vegetative nuclei. The majority of vegetative nuclei re-entered the cell cycle after 12 h of culture. Replication in the vegetative cells preceded division of the vegetative cell, a prerequisite for pollen-derived embryogenesis.
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  • 30
    ISSN: 1432-2242
    Keywords: Intergeneric crosses ; Somatic hybridization ; Sinapis alba ; Brassica napus ; Heterodera schachtii ; Nematode resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sexual and somatic hybrid plants have been produced between Sinapis alba L. (white mustard) and Brassica napus L. (oil-seed rape), with the aim to transfer resistance to the beet cyst nematode Heterodera schachtii Schm. (BCN) from white mustard into the oil-seed rape gene pool. Only crosses between diploid accessions of S. alba (2n = 24, Sa1Sa1) as the pistillate parent and several B. napus accessions (2n = 38, AACC) yielded hybrid plants with 31 chromosomes. Crosses between tetraploid accessions of S. alba (2n = 48, Sa1Sa1Sa1Sa1) and B. napus were unsuccessful. Somatic hybrid plants were also obtained between a diploid accession of S. alba and B. napus. These hybrids were mitotically unstable, the number of chromosomes ranging from 56 to more than 90. Analysis of total DNA using a pea rDNA probe confirmed the hybrid nature of the sexual hybrids, whereas for the somatic hybrids a pattern identical to that of B. napus was obtained. Using chloroplast (cp) and mitochondrial (mt) DNA sequences, we found that all of the sexual F1 hybrids and somatic hybrids contained cpDNA and mtDNA of the S. alba parent. No recombinant mtDNA or cpDNA pattern was observed. Three BC1 plants were obtained when sexual hybrids were back-crossed with B. napus. Backcrossing of somatic hybrids with B. napus was not successful. Three sexual hybrids and one BC1 plant, the latter obtained from a cross between a sexual hybrid and B. napus, were found to show a high level of BCN resistance. The level of BCN resistance of the somatic hybrids was in general high, but varied between cuttings from the same plant. Results from cytological studies of chromosome association at meiotic metaphase I in the sexual hybrids suggest partial homology between chromosomes of the AC and Sa1 genomes and thus their potential for gene exchange.
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  • 31
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    Theoretical and applied genetics 85 (1993), S. 994-1000 
    ISSN: 1432-2242
    Keywords: Brassica napus ; DNA fingerprinting ; Simple repetitive sequences ; Cultivar identification ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Brassica napus genome has been investigated by DNA fingerprinting with six synthetic oligonucleotide probes complementary to simple repetitive sequences, namely (GATA)4, (GACA)4, (GGAT)4, (CA)8, (CT)8 and (GTG)5. While all sequence motifs were found to be present in the B. napus genome, their organization and abundance varied considerably. Among the investigated probes, (GATA)4 revealed the highest level of intraspecific polymorphism and distinguishes not only between cultivars but even between different individuals belonging to the same cultivar. In contrast, (GTG)5, (GACA)4 and (GGAT)4 produced relatively homogeneous fingerprint patterns throughout different cultivars, while hybridization to (CT)8 and (CA)8 resulted in only a few weak bands superimposed on a smear. The isoschizomeric pair Hpa II and Msp I revealed the presence of methylated cytosines in the vicinity of (GATA)m repeats. The applicability of simple repetitive sequence polymorphisms as molecular markers for Brassica species is discussed.
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  • 32
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    Plant and soil 153 (1993), S. 19-31 
    ISSN: 1573-5036
    Keywords: Brassica carinata ; Brassica napus ; calcium ; chloride ; growth analysis ; leaf area ratio ; magnesium ; net assimilation rate ; potassium ; relative growth rate ; seawater ; sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The response of two rapid-cycling Brassica species differing in tolerance to seawater salinity was studied over a period of 24 days. In response to 8 dS m−1 salinity, the two Brassica species showed clear differences in the changes in relative growth rate (RGR), net assimilation rate (NAR) and leaf area ratio (LAR). The RGR of B. napus was slightly reduced by salinity, wheareas the RGR of B. carinata was largely reduced in the early stages of salinization. LAR of B. napus was affected by salinity in the later stages of growth and significantly correlated with the reduction in RGR. On the other hand, the NAR of B. carinata was decreased by salinity, corresponding to the decrease of the RGR of B. carinata. The NAR of B. napus was not significantly affected by salinity according to analysis of covariance. The shoot concentrations of Na, Mg and Cl increased while the concentrations of K and Ca decreased sharply during the first 5 days of salinization; subsequently, all ion concentrations remained relatively constant. The concentrations of Na, K, Ca, Mg and Cl in the root were similarly affected by salinity. There were no significant differences of ion concentrations between species that could be related to the differences in salt tolerance. Thus, the differences in salt tolerance between species can not be related to differences in specific-ion effects, but may be related to some factor that reduces the NAR of B. carinata during the early stages of growth.
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  • 33
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    Plant molecular biology 23 (1993), S. 511-524 
    ISSN: 1573-5028
    Keywords: Brassicaceae ; Brassica napus ; glucosinolate ; myrosinase ; multigene family ; thioglucoside glucohydrolase (EC 3.2.3.1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The glucosinolate hydrolyzing enzymes myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) are encoded by a multigene family consisting of two subgroups. The first two nuclear genes representing each of these two subgroups of the new gene family, Myr1.Bn1 and Myr2.Bn1, from Brassica napus have been cloned and sequenced. Based on conserved regions in cDNA of three species, PCR (polymerase chain reaction) primers were made, and used to amplify and characterize the structure of the myrosinase genes in seven species of Brassiceae. Southern hybridization analysis of PCR products and genomic DNA indicates that myrosinase is encoded by at least 14 genes in B. napus, with similar numbers in the other species of Brassicaceae investigated. The Myr1 gene cloned from B. napus has a 19 amino acid signal peptide and consists of 11 exons of sizes ranging from 54 to 256 bp and 10 introns of sizes from 75 to 229 bp. The Myr2 gene has a 20 amino acid signal peptide and consists of 12 exons ranging in size from 35 to 262 bp and 11 introns of sizes from 81 to 131 bp. The exons from the two genes have 83% homology at the amino acid level. The intron-exon splice sites are of GT..AG consensus type. The signal peptides and presence of sites for N-linked glycosylation, suggest transport and glycosylation through the ER-Golgi complex. The differences between the two genes are discussed on the basis of their predicted expression at different developmental stages in the plant. Both genes show homology to a conserved motif representing the glycosyl hydrolase family of enzymes.
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  • 34
    ISSN: 1573-5028
    Keywords: Brassica napus ; deletion analysis ; napin ; promoter ; seed ; storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The promoter and upstream region of the Brassica napus 2S storage protein napA gene were studied to identify cis-acting sequences involved in developmental seed-specific expression. Fragments generated by successive deletions of the 5′ control region of the napA gene were fused to the reporter gene β-glucuronidase (GUS). These constructs were used to transform tobacco leaf discs. Analyses of GUS activities in mature seeds from the transformed plants indicated that there were both negatively and positively acting sequences in the napin gene promoter. Deletion of sequences between −1101 and −309 resulted in increased GUS activity. In contrast, deletion of sequences between −309 and −211 decreased the expression. The minimum sequence required for seed-specific expression was a 196 bp fragment between −152 and +44. Further 5′ deletion of the fragment to −126 abolished this activity. Sequence comparison showed that a G box-like sequence and two sequence motifs conserved between 2S storage protein genes are located between −148 to −120. Histochemical and fluorometric analysis of tobacco seeds showed that the spatial and developmental expression pattern was retained in the deletion fragments down to −152. However, the expression in tobacco seeds differed from the spatial and temporal expression in B. napus. In tobacco, the napA promoter directed GUS activity early in the endosperm before any visible activity could be seen in the heart-shaped embryo. Later, during the transition from heart to torpedo stages, the main expression of GUS was localized to the embryo. No significant GUS activity was found in either root or leaf.
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  • 35
    ISSN: 1573-5028
    Keywords: Brassica napus ; pollen ; polygalacturonase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone, Sta 44-4, corresponding to a mRNA highly expressed in Brassica napus cv. Westar stamens, was isolated by differential screening and characterized. Northern blot and in situ analyses demonstrated that Sta 44-4 is synthesized in pollen beginning at the late uninucleate stage and reaches a maximum in trinucleate microspores. Sta 44-4 displayed significant sequence similarity to known pollen polygalacturonase genes. The B. napus pollen polygalacturonase gene was shown to be part of a small gene family and to display some polymorphism among different cultivars.
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  • 36
    ISSN: 1573-5028
    Keywords: Brassica napus ; cold acclimation ; gene isolation ; human tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to identify genes involved in cold acclimation, we have constructed a cDNA library from Brassica napus (cv. Samouraï) cold-acclimated etiolated seedlings. By differential screening, a cDNA clone named pBnC24 (Brassica napus Cold), corresponding to a new cold-inducible plant gene, was isolated. Northern blot hybridizations using total RNA from acclimated and unacclimated seedlings confirmed that BnC24 represents a cold-regulated gene. In contrast with a number of cold-inducible plant genes, BnC24 does not seem to be responsive to abscisic acid (ABA). In addition, further screening of the ‘cold-acclimated’ cDNA library using pBnC24 cDNA as a probe, allowed the isolation of a second type of homologous cDNA. Sequence analysis showed that the two BnC24 genes encode basic 24 kDa proteins, which are highly hydrophilic and rich in alanine, lysine and arginine. The nucleotide and deduced amino acid sequences of these clones do not show any homology with other previously described cold-induced plants genes. However they have strong homology with a recently discovered human tumour gene, bbc1 (breast basic conserved), which seems to be highly conserved in eukaryotes.
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  • 37
    ISSN: 1573-5060
    Keywords: Brassica napus ; ×Brassicoraphanus ; Heterodera schachtii ; intergeneric crosses ; introgression ; meiosis ; nematode resistance ; Raphanus sativus ; rape kale ; oil-seed rape ; fodder rape ; raparadish ; radish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The possibilities to transfer important traits and in particular resistance to the beet cyst nematode (Heterodera schachtii, abbrev. BCN) from Raphanus sativus to Brassica napus were investigated. For these studies B. napus, R. sativus, the bridging hybrid ×Brassicoraphanus (Raparadish) as well as offspring of the cross ×Brassicoraphanus (Raparadish) ×B. napus were used. Reciprocal crosses between B. napus and R. sativus were unsuccessful, also with the use of embryo rescue. Crosses between ×Brassicoraphanus as female parent and B. napus resulted in a large number of F1 hybrids, whereas the reciprocal cross yielded mainly matromorphic plants. BC1, BC2 and BC3 plants were obtained from backcrosses with B. napus, which was used as the male parent. F1 hybrids and BC plants showed a large variation for morphology and male and female fertility. Cuttings of some F1 and BC1 plants, obtained from crosses involving resistant plants of ×Brassicoraphanus, were found to possess a level of resistance similar to that of the resistant parent. These results and indications for meiotic pairing between chromosomes of genome R with those of the genomes A and/or C suggest that introgression of the BCN-resistance of Raphanus into B. napus may be achieved.
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  • 38
    ISSN: 1573-5060
    Keywords: Brassica juncea ; Brassica napus ; Moricandia arvensis ; intergeneric hybridization ; ovary culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wide hybridizations between M. arvensis and Brassica amphidiploid species (B. napus and B. juncea) were carried out in order to incorporate desirable traits of M. arvensis into Brassica crops. Crossing barriers between them were present without the use of in vitro techniques. F1 hybrids have been produced through ovary culture, when M. arvensis were used as a female parent. Higher hybrid embryo productivity (3.07 embryos per pollination) was obtained in the cross of M. arvensis x B. napus than in that of M. arvensis x B. juncea (0.79 embryos). The hybridity was confirmed by morphology, cytology, isozyme and Southern analyses. The first backcrossing progenies and open pollinated ones were produced.
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  • 39
    ISSN: 1573-5036
    Keywords: Brassica napus ; K release ; nonexchangeable potassium ; particle size ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The release of nonexchangeable potassium by the different particle size fractions of two soils was studied with a culture device designed to confine soil samples in the rhizosphere of rape (Brassica napus cv Drakkar). After 8 days of cropping, the contribution of nonexchangeable K to K uptake ranged from 50% in the fine clay to 80–100% in the coarser fractions. Due to their high supplying power and their relative abundance, the silt fractions provided a major part of the supply of K by these soils.
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  • 40
    ISSN: 1573-5060
    Keywords: Albugo candida ; Brassica juncea ; Brassica napus ; EDTA ; gamma-ray ; interspecific cross ; leaf waxiness ; white rust inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Three interspecific crosses made between Brassica juncea and Brassica napus revealed digenic control with epistatic interaction for white rust resistance trait. The investigation also indicated a close association of parental species type and different grades of leaf waxiness with white rust resistance. It is possible to recover waxy or medium waxy juncea types with white rust resistance, though in low frequency. Treatment of hybrid seeds with EDTA and low doses of gamma-rays seem to have little effect on shuffeling of genomes and genes.
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  • 41
    ISSN: 1573-5060
    Keywords: Brassica napus ; cross prediction ; genetic parameters ; oilseed rape ; SSD lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The reliability of a selection among crosses based on a cross prediction in early generations was investigated in spring rapeseed. The performance of the parents, the F2 generation, and random F3 lines from four crosses were used to predict the probability of finding superior recombinant lines. These predictions were made for two years and compared with the observed performance of F6 lines in the second of these two years and in an additional year. Predicted and observed performances coincided reasonably for the characters plant height, standability, maturity and an index calculated from seed yield, oil content and protein content. For seed yield and flowering time, the predictions were very unreliable. In conclusion, prediction methods may be useful in rapeseed breeding, if quality traits are of major commercial interest.
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  • 42
    ISSN: 1573-5060
    Keywords: Brassica napus ; microspore derived population ; RAPD ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The segregation of RFLP and RAPD markers was compared in two oilseed rape (Brassica napus L.) breeding populations from the cross ‘Topas’ x R4, the latter being a low linolenic mutation line. A total progeny of 68 F2 and 40 microspore derived plants were studied with 25 markers. The results indicated a significant excess of ‘Topas’ alleles at five RAPD loci in the microspore derived population. This suggests that genomic regions which probably affect microspore culture ability do not have identical distribution in the two population types.
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  • 43
    ISSN: 1573-5060
    Keywords: Brassica napus ; doubled haploid ; inheritance ; seed colour ; vernalization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Doubled haploid (DH) and F2 populations were used to study the inheritance of seed colour and one DH population was used to study vernalization requirement in Brassica napus. Seed colour was primarily determined by the maternal genotype, but effects of the paternal parent were obvious in a reciprocal F2. The seed colour distributions in the populations fit a trigenic ratio with black seed colour being dominant over yellow seed colour. In the proposed model, which was supported by segregation ratios in an F2 population from a cross with a black-seeded maternal parent (but not its reciprocal) and segregation ratios in 4 DH populations, black seeds were formed when the A gene was homozygous dominant and at least one dominant allele was present at the B locus, brown seeds developed when one or more recessive alleles were present at the A locus and one (or more) dominant alleles was (were) present at any of the three loci and yellow seeds occurred when all three loci were homozygous recessive. The vernalization study showed that the spring habit was dominant to the winter habit and that the requirement for vernalization was controlled by a major and a minor gene. The enhanced resolution of genetic classes afforded by the use of DHs allowed the relative effects of the major and minor vernalization genes to be determined. In the proposed model the major gene was sufficient to allow nonvernalized plants to flower in 62 days or less, the minor gene allowed nonvernalized plants to flower in 63 to 77 days and double recessive genotypes required more than 77 days to flower without vernalization.
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  • 44
    ISSN: 1573-5028
    Keywords: acyl ; Brassica napus ; fatty acid synthesis ; plastidial location ; seed ; thioesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acyl-ACP thioesterases are involved in regulating chain termination of fatty acid biosynthesis in plant systems. Previously, acyl-ACP thioesterase purified from Brassica napus seed tissue has been shown to have a high preference for hydrolysing oleoyl-ACP. Here, oligonucleotides derived from B. napus oleoyl-ACP thioesterase protein sequence data have been used to isolate two acyl-ACP thioesterase clones from a B. napus embryo cDNA library. The two clones, pNL2 and pNL3, contain 1642 bp and 1523 bp respectively and differ in the length of their 3′ non-coding regions. Both cDNAs contain open reading frames of 366 amino acids which encode for 42 kDa polypeptides. Mature rape thioesterase has an apparent molecular weight of 38 kDa on SDS-PAGE and these cDNAs therefore encode for precursor forms of the enzyme. This latter finding is consistent with the expected plastidial location of fatty acid synthase enzymes. Northern blot analysis shows thioesterase mRNA size to be ca. 1.6 kb and for the thioesterase genes to be highly expressed in seed tissue coincident with the most active phase of storage lipid synthesis. There is some sequence heterogeneity between the two cDNA clones, but overall they are highly homologous sharing 95.7% identity at the DNA level and 98.4% identity at the amino acid level. Some sequence heterogeneity was also observed between the deduced and directly determined thioesterase protein sequences. Consistent with the observed sequence heterogeneity was Southern blot data showing B. napus thioesterase to be encoded by a small multi-gene family.
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  • 45
    ISSN: 1573-5028
    Keywords: cruciferin ; 12S globulin ; Brassica napus ; gene families ; transcription ; in situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major storage protein in seeds of Brassica napus, the 12S globulin cruciferin, is composed of three different groups of subunits; cru1, cru2/3 and cru4. By using gene family-specific probes, we have investigated the accumulation, rate of synthesis and spatial distribution of transcripts corresponding to the different groups of cruciferin subunits in developing seeds. Cruciferin transcripts derived from different gene families accumulate coordinately to comparable amounts during seed development. The corresponding gene families are, however, transcribed at different rates. Investigation of the spatial distribution of transcripts corresponding to each group of cruciferin subunits in the developing seed by in situ hybridization, revealed that mRNAs of all three types accumulate in both axis and cotyledons. Transcripts derived from cru1 and cru4 gene families show a similar cell specificity and accumulate in a similar spatial manner during seed development. In contrast, mRNAs corresponding to the cru2/3 gene family are expressed with a partly different cell specificity and show a slightly different pattern of accumulation in the axis and cotyledons, with a delayed accumulation in epidermal cells. In the cotyledons, the initial accumulation of this type of cruciferin mRNAs is also distinguished from the two other types. The differences in cell specificity are seen in the root cap and in provascular cells, where mRNAs belonging to the cru2/3 family are absent.
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  • 46
    ISSN: 1573-5028
    Keywords: active site ; β-glycosidases ; Brassica napus ; glucosinolates ; myrosinase ; thioglucoside ; glucohydrolase (EC 3.2.3.1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Myrosinase isoenzymes are known to be encoded by two different families of genes denoted MA and MB. Nucleotide sequence analysis of a Brassica napus genomic clone containing a gene for myrosinase revealed it to be a pseudogene of the MA family. The gene spans more than 5 kb and contains at least 12 exons. The exon sequence of the gene is highly similar to myrosinase cDNA sequences. However, the gene displays three potential or actual pseudogene characters. Southern blot analysis using probes from the 3′ portions of the genomic and B. napus MA and MB cDNA clones showed that MA type myrosinases are encoded by approximately 4 genes, while MB type myrosinases are encoded by more than 10 genes in B. napus. Northern blots with mRNA from seeds and young leaves probed with the MA-and MB-specific probes showed that the MA and MB myrosinase gene families are differentially expressed. Myrosinases are highly similar to proteins of a β-glycosidase enzyme family comprising both β-glycosidases and phospho-β-glycosidases of as diverged species as archaebacteria, bacteria, mammals and plants. By homology to these β-glycosidases, putative active site residues in myrosinase are discussed on the basis of the similarity between β-glycosidases and cellulases.
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  • 47
    ISSN: 1615-6102
    Keywords: Brassica napus ; Cell division ; High temperature ; Microspore ; Embryogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.
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  • 48
    ISSN: 1617-4623
    Keywords: Intrachromosomal recombination ; Recombination frequency ; Allelic position ; Non-allelic position ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously described a non-selective method for scoring somatic recombination in the genome of whole plants. The recombination substrate consists of a defective partial dimer of Cauliflower Mosaic Virus (CaMV) sequences, which can code for production of viable virus only upon homologous recombination; this leads to disease symptoms on leaves. Brassica napus plants (rapeseed) harbouring the recombination substrate as a transgene were used to examine the time in plant development at which recombination takes place. The analysis of three transgene loci revealed recombination frequencies specific for each locus. Recombination frequencies were increased if more than one transgene locus was present per genome, either in allelic (homozygosity of the transgene locus) or in non-allelic positions. In both cases, the overall recombination frequency was found to be elevated to approximately the sum of the frequencies for the individual transgene loci or slightly higher, suggesting that the respective transgene loci behave largely independently of each other. For all plants tested (single locus, two or multiple loci) maximal recombination frequencies were of the order of 10−6 events per cell division.
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  • 49
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    Transgenic research 2 (1993), S. 356-364 
    ISSN: 1573-9368
    Keywords: Brassica napus ; oilseed rape ; transgenic crops ; pollen dispersal ; insect pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The objective of this study was to evaluate pollen dispersal inBrassica napus (oilseed rape). The selectable marker, used to follow pollen movement, was a dominant transgene (bar) conferring resistance to the herbicide glufosinate-ammonium. Transgenic and non-transgenic plants of the cultivar Westar were planted in a 1.1 ha field trial, with the transgenic plants in a 9 m diameter circle at the centre, surrounded by non-transgenic plants to a distance of at least 47 m in all directions. A 1 m circle of non-transgenic plants was sown in the centre of the transgenic area to allow estimation of the level of pollen dispersal when plants were in close contact. Honeybee hives were placed at the trial site to optimize the opportunity for cross-pollination. During the flowering period, regular observations were made of the number of plants flowering and the number and type of insects present in 60 1 m2 areas. These areas were located uniformly around the plot at distances of 1, 3, 6, 12, 24, 36 and 47 m from the edge of the 9 m circle of transgenic plants. Seed samples were harvested from each of the 7 distances so that approximately 20% of the circumference of the plot was sampled at each distance. The centre non-transgenic circle was also sampled. Plants were grown from the seed samples and sprayed with glufosinate to estimate the frequency of pollen dispersal at each distance. In order to screen enough samples to detect low frequency cross-pollination events, seed samples were tested in the greenhouse and on a larger scale in the field. Results were confirmed by testing progeny for glufosinate resistance and by Southern blot analysis. The estimated percentage of pollen dispersal in the non-transgenic centre circle was 4.8%. The frequency was estimated to be 1.5% at a distance of 1 m and 0.4% at 3 m. The frequency decreased sharply to 0.02% at 12 m and was only 0.00033% at 47 m. No obvious directional effects were detected that could be ascribed to wind or insect activity.
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  • 50
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    Protoplasma 174 (1993), S. 147-157 
    ISSN: 1615-6102
    Keywords: Abscisic acid ; Brassica napus ; Embryo maturation ; Reserves metabolism ; Somatic embryos ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparison of embryos, cultured for increasing periods of time with and without abscisic acid (ABA), was undertaken to investigate, at the ultrastructural level, the influence of this growth regulator on the maturation of rapeseed (Brassica napus) somatic embryos. In the absence of ABA, the embryos germinated precociously while lipid bodies (LB), which were not numerous, soon degraded, as revealed by a depletion process associated with the appearance of morphologically mature glyoxysomes and an increase in the number of mitochondria. Moreover, a lack of protein bodies indicated that storage protein accumulation was not initiated under these conditions. On the contrary, the addition of ABA (10 μM) induced marked modification of embryo metabolism. Indeed, ABA completely prevented precocious embryo germination and inhibited lipid reserve catabolism. Moreover, the formation of small vacuoles and proliferation of rough endoplasmic reticulum in their vicinity suggested the onset of storage protein accumulation. After 15 days in the presence of ABA, the embryos contained abundant lipid and protein bodies. Nevertheless, these somatic embryos were not exactly the same as their mature zygotic counterparts since differences were found in chloroplasts, amyloplasts, and nuclear structures. These observations suggest that additional factors might be required to obtain fully mature somatic embryos.
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  • 51
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    Theoretical and applied genetics 83 (1992), S. 476-479 
    ISSN: 1432-2242
    Keywords: Haploidy ; Brassica napus ; Yellow-seeded canola
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The use of haploidy to introgress recessive traits into Brassica napus canola is illustrated by describing the properties of doubled haploids obtained by microspore culture from crosses between a yellow-seeded rapeseed line (low erucic acid, high glucosinolate) and black-seeded canola. Of the 99 doubled haploid lines that were produced, 3 were yellow-seeded canola lines. This result was not significantly different than the predicted frequency of 1 in 64 for the homozygous recessive phenotype in a doubled haploid population segregating for six recessive genes. Thus, the study supports previous models of inheritance determined for yellow seededness and glucosinolate content in Brassica napus. Also, since the chances of obtaining a plant with the same characteristics in a F2 population are 1 in 4,096, the underscore results the advantages of using haploidy to introgress recessive traits into Brassica napus canola.
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  • 52
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    Theoretical and applied genetics 84 (1992), S. 403-410 
    ISSN: 1432-2242
    Keywords: Interspecific breeding ; Sinapis alba ; Brassica napus ; Isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Isozyme analysis of Brassica napus cv ‘Topas’ and CGRC5006 as well as of Sinapis alba cv ‘Emergo’ revealed significant polymorphism between the two species for the isozymes, aconitate hydratase, glucose phosphate isomerase, and diaphorase. F1 hybrids between B. napus ‘5006’ and S. alba cv ‘Emergo’ were backcrossed to B. napus cv ‘Topas’, and the S1 progeny of the first two backcrosses were studied isozymically. At the backcross one level the frequency of S. alba or S. alba plus B. napus patterns observed ranged from 18% to 87% across the four lines studied. There were differences between lines for the frequency of S. alba patterns, which could have an impact on the efficiency of selection for subsequent backcrossing. By the backcross two generation in one of the two lines studied, GR86-24, the S. alba patterns for GPI and DIA had been lost, while in the other line, GR86-28, the S. alba pattern for ACO had been lost, resulting in lost opportunity for S. alba gene transfer. In a wide cross such as S. alba x B. napus, which requires an intensive effort to accomplish, the isozymes ACO, GPI, and DIA may serve as useful markers to ensure gene transfer between the two species has occurred. In addition, the identification of lines with divergent isozyme patterns from B. napus will provide the basis for establishing linkages between S. alba traits of interest and isozyme markers.
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  • 53
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    Theoretical and applied genetics 84 (1992), S. 303-306 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Outcrossing rate ; Selfing rate ; Mixed mating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Rapeseed (Brassica napus) is a predominantly selfpollinated crop with about one-third outcrossing. The outcrossing rate may be influenced by environmental factors, and hence changes in the heterozygosity level of a variety may occur during multiplication. In an investigation on environmental variation in outcrossing, we estimated the outcrossing rate in the Swedish spring rapeseed cv ‘Topas’ by isozyme analysis and found that outcrossing varied from 12% to 47% over five locations in Sweden, Denmark and Germany. Among flowers at different positions on the same plant, average outcrossing varied from 11% at the top to 39% at the bottom of the plant. In conclusion, environmental factors can greatly influence the outcrossing rate in rapeseed, and an investigation therefore merit further studies.
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  • 54
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    Theoretical and applied genetics 85 (1992), S. 222-228 
    ISSN: 1432-2242
    Keywords: Brassica napus ; Raphanus sativus ; Cytoplasmic male sterility ; Restorer ; Isozyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Co-segregation studies of isozyme markers and male fertility restoration showed that a restorer gene from radish was introduced into rapeseed along with an isozyme marker (Pgi-2). The radish chromosome segment carrying these genes was introgressed into rapeseed through homoeologous recombination, substituting for some of the rapeseed alleles. By crossing heterozygous restored plants to male-sterile lines and to maintainers, tight linkage was found between the restorer gene and the marker. The recombination fraction was estimated at 0.25 ± 0.02%. Although few restored plants lacked the radish isozyme marker, it was still possible to distinguish male-fertile from male-sterile plants by their PGI-2 patterns. Furthermore, homozygous and heterozygous restored plants could be separated by specific PGI-2 phenotypes. Thus, the Pgi-2 marker is now currently used in restorer breeding programs.
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  • 55
    ISSN: 1432-2145
    Keywords: Self-incompatibility ; S-locus genes ; Brassica napus ; Transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Self-compatible Brassica napus var ‘Westar’ was transformed with SLG, the S-locus-derived gene that encodes S-locus-specific glycoproteins (SLSG). Four allelic variants of SLG isolated from self-incompatible B. oleracea and B. campestris strains homozygous for different S alleles were used. We show that the transgenic plants synthesized SLSG with the same apparent charge, molecular weight, and antigenic properties as that produced by the corresponding self-incompatible strains from which the cloned SLG genes were isolated. In addition, transgene-encoded SLSG was detected specifically in the papillar cells of the stigma, and was correctly targeted to the papillar cell wall. However, SLSG was produced at reduced levels in transgenic plants relative to self-incompatible strains. The introduction of the SLG genes did not confer a self-incompatibility phenotype on the ‘Westar’ cultivar.
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  • 56
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    Journal of chemical ecology 18 (1992), S. 875-884 
    ISSN: 1573-1561
    Keywords: Aggregation pheromone ; olfactometer ; field trapping ; Coleoptera ; Chrysomelidae ; Phyllotreta cruciferae ; Brassica napus ; crucifer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Laboratory olfactometer bioassays and field trapping experiments showed that the flea beetle,Phyllotreta cruciferae (Goeze), was highly attracted by oilseed rape(Brassica napus L.) when flea beetles were on the plant. This attraction was mediated by a flea beetle-produced aggregation pheromone based upon: (1) Oilseed rape damaged mechanically, or byP. cruciferae, or by diamondback moth,Plutella xylostella (L.), did not attractP. cruciferae. (2) Contact with the plants or feeding was required for the production of aggregation pheromone because oilseed rape alone was not attractive when separated from flea beetles by a screen. (3) Equal numbers of males and females were attracted.
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  • 57
    ISSN: 1573-1561
    Keywords: Ceutorhynchus assimilis ; Coleoptera ; Curculionidae ; Brassica napus ; semiochemicals ; plant volatiles ; olfaction ; host plant ; attractant ; electroantennogram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennograms (EAGs) were recorded from male and female cabbage seed weevils (Ceutorhynchus assimilis Payk.) in response to volatiles isolated and identified from the odor of oilseed rape (Brassica napus ssp.oleifera DC. cv. Ariana). Relatively large EAGs were obtained on stimulation with volatiles produced by the oilseed rape crop at the time when seed weevils were actively searching for host plants. Artificial rape odor without certain key volatile compounds was in most cases significantly less stimulatory than odor containing these volatiles. There were significant differences in the EAG response of the sexes ofC. assimilis to the green leaf volatiles of oilseed rape and several terpenes present in rape flower odor. The importance of the qualitative and quantitative composition of host-plant odor in host location byC. assimilis is discussed.
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  • 58
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    Plant and soil 142 (1992), S. 315-321 
    ISSN: 1573-5036
    Keywords: Canola/rapeseed ; Rhizoctonia solani AG2-1 ; cuticle ; epidermal cell wall ; Brassica napus ; Sinapis alba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A study was conducted to determine whether the cuticles in two genera of the family Cruciferae are effective barriers to infection by Rhizoctonia solani, and whether differences in cuticle and epidermal cell wall thickness and morphology of epicuticular wax exist between resistant and susceptible cultivars. As Canola/rapeseed (Brassica napus) and mustard (Sinapis alba) plants develop from 1 to 3 weeks of age, they become increasingly resistant to R. solani AG2-1 seedling root rot. Seven-day-old seedlings of S. alba cultivars are invariably more resistant than B. napus cultivars. Brassica napus cultivars do not show an obvious cuticle layer at 1 week but at 3 weeks the presence of a cuticle is seen through autofluorescence with a concomitant increase in resistance to R. solani. Removal of the cuticle from 3-week-old hypocotyls by chloroform treatment results in a decrease in cuticular autofluorescence and a significant increase in disease severity in both resistant and susceptible cultivars. Three-week-old plants of S. alba have a much lower percent disease rating and a significantly (p=0.05) thicker cuticle layer than similar-age plants of B. napus. The results suggest that the cuticle plays an important role in the resistance of S. alba and older plants of B. napus to infection by R. solani.
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  • 59
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    Plant molecular biology 18 (1992), S. 387-398 
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Brassicaceae ; Brassica napus ; glucosinolate ; myrosinase ; Sinapis alba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A full-length cDNA clone (MB3) and three partial clones (MA1, MB1 and MB2) which encode myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) were isolated from a Sinapis alba (white mustard) cDNA library. Nucleotide sequence analysis of these clones revealed that they are encoded by a gene family. Southern blot analysis with gene-specific probes showed that the gene family consists of a least two subfamilies (MA and MB) each with several members both in S. alba and in Brassica napus (oilseed rape). In Arabidopsis thaliana (wall cress) only three myrosinase genes seem to be present. Northern blot analysis indicated that all the myrosinase mRNA species have the same size, approximately 1.95 kb.
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  • 60
    ISSN: 1573-5028
    Keywords: Brassica napus ; chloroplast ; 3-isopropylmalate dehydrogenase ; molecular evolution ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both insect and mammalian genes have previously been cloned by genetic complementation in yeast. In the present report, we show that the method can be applied also to plants. Thus, we have cloned a rape cDNA for 3-isopropylmalate dehydrogenase (IMDH) by complementation of a yeast leu2 mutation. The cDNA encodes a 52 kDA protein which has a putative chloroplast transit peptide. The in vitro made protein is imported into chloroplasts, concomitantly with a proteolytic cleavage. We conclude that the rape cDNA encodes a chloroplast IMDH. However, Southern analysis revealed that the corresponding gene is nuclear. In a comparison of IMDH sequences from various species, we found that the rape IMDH is more similar to bacterial than to eukaryotic proteins. This suggests that the rape gene could be of chloroplast origin, but has moved to the nucleus during evolution.
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  • 61
    ISSN: 1573-5028
    Keywords: methionine enhancement ; seed proteins ; Brassica napus ; transgenic expression ; Brazil nut ; nutritional quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have increased the methionine content of the seed proteins of a commercial winter variety of canola by expressing a chimeric gene encoding a methionine-rich seed protein from Brazil nut in the seeds of transgenic plants. Transgenic canola seeds accumulate the heterologous methionine-rich protein at levels which range from 1.7% to 4.0% of the total seed protein and contain up to 33% more methionine. The precursor of the methionine-rich protein is processed correctly in the seeds, resulting in the appearance of the mature protein in the 2S protein fraction. The 2S methionine-rich protein accumulates in the transgenic seeds at the same time in development as the canola 11S seed proteins and disappears rapidly upon germination of the seed. The increase in methionine in the canola seed proteins should increase the value of canola meal which is used in animal feed formulations.
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  • 62
    ISSN: 1573-5028
    Keywords: acyl carrier protein ; Brassica napus ; lipid synthesis ; seed-specific expression ; transgenic tobacco ; 5′ flanking region
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acyl carrier protein (ACP) is a key component of the fatty acid biosynthetic machinery in plants. A 1.4 kb 5′ flanking region of a Brassica napus ACP gene (ACP05) was transcriptionally fused to the reporter gene β-glucuronidase (GUS), and expression of the chimaeric gene monitored in transgenic tobacco. GUS activity was found to increase through seed development reaching a maximum value, coincident with the most active phase of storage lipid synthesis that was, on average, 100-fold higher than that observed in leaf. In control plants transformed with CaMV 35S-GUS constructs, GUS activity was similar in leaf and all stages of seed development. Based on average values, the level of GUS expression obtained via the ACP promoter was comparable to that obtained from the CaMV 35S promoter. We therefore conclude that the isolated 5′ ACP flanking sequence represents a strong promoter element involved in the developmental regulation of storage lipid synthesis in B. napus seed tissue. Putative regulatory elements in the 5′ upstream region of ACP05 were identified by dot matrix analysis and by sequence comparison with the upstream regions from a second seed-expressed rape ACP gene and from an Arabidopsis ACP gene.
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  • 63
    ISSN: 1573-5028
    Keywords: anther ; Arabidopsis thaliana ; Brassica napus ; tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Brassica napus cDNA clone A9 and the corresponding Arabidopsis thaliana gene have been sequenced. The B. napus cDNA and the A. thaliana gene encode proteins that are 73% identical and are predicted to be 10.3 kDa and 11.6 kDa in size respectively. Fusions of an RNase gene and the reporter gene β-glucuronidase to the A. thaliana A9 promoter demonstrated that in tobacco the A9 promoter is active solely in tapetal cells. Promoter activity is first detectable in anthers prior to sporogenous cell meiosis and ceases during microspore premitotic interphase. The deduced A9 protein sequence has a pattern of cysteine residues that is present in a superfamily of seed plant proteins which contains seed storage proteins and several protease and α-amylase inhibitors.
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  • 64
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    Plant molecular biology 19 (1992), S. 1049-1055 
    ISSN: 1573-5028
    Keywords: Brassica napus ; rapeseed ; gene expression ; nucleotide sequence ; storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated a five-member gene subfamily which encodes cruciferin, a legumin-like 12S storage protein of Brassica napus L., and have analyzed the structure and expression of the family members in developing embryos. Sequence analysis has shown that the coding regions of all five genes are highly similar, with the two most divergent members of the family retaining 89% sequence identity. The analysis of this cruciferin gene family's expression indicates that the developmental pattern of expression of each gene is similar, and the steady-state mRNA levels of each gene are approximately equivalent to each other at all developmental stages.
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  • 65
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    Plant cell, tissue and organ culture 31 (1992), S. 141-149 
    ISSN: 1573-5044
    Keywords: Brassica napus ; cryopreservation ; in vitro embryo ; microspore ; rapeseed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microspore cryopreservation is a potentially powerful method for long-term storage of germplasm for in vitro embryo production in plant species. In this study, several factors influencing embryo production following the ultra-low temperature (−196 °C in liquid nitrogen) storage of isolated microspores of rapeseed (Brassica napus L.) were investigated. Microspores were prepared in cryogenic vials and subjected to various cooling treatments before immersion in liquid nitrogen for varying periods. Efficiency of microspore cryopreservation was reflected by in vitro embryo production from frozen microspores. Of all the cooling treatments, microspores treated with a cooling rate of 0.25% °C/min and a cooling terminal temperature of −35 °C before immersion in liquid nitrogen produced the highest embryo yields (18% and 40% of unfrozen controls in two genotypes, respectively). Fast thawing in a 35 °C water bath was necessary to recover a high number of embryos from microspore samples being frozen at a higher cooling rate, while thawing speed did not affect samples after freezing at a slower cooling rate. The storage density of cryopreserved microspores affected embryo production. Storage at the normal culture density (8×104 microspores/ml) was less efficient for embryo production than at high densities (4×106 microspores/ml and 1.6×107 microspores/ml), although no significant difference was found between the high densities. Evaluation of plant lines derived from frozen microspores indicated no variation in isozyme pattern and no enhanced cold tolerance of these lines. Isolated microspores of B. napus could be stored for extended period for in vitro embryo production.
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  • 66
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    Euphytica 59 (1992), S. 221-229 
    ISSN: 1573-5060
    Keywords: Brassica napus ; simazine tolerance ; polygenic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Substantial variation in tolerance to the triazine herbicide simazine was observed among a wide range of Brassica napus cultivars grown in a hydroponic screening system. None of these cultivars was as tolerant of are simazine treatment as the Canadian cultivar Triton which carries cytoplasmic gene(s) which confer a high level of resistance through their modification of chloroplast membranes to which triazine herbicides normally bind. A field study showed that the most tolerant cultivar Haya had a significantly higher yield than Triton in both handweeded plots and plots treated with 1000 ml/ha simazine. This finding supported other observations that the yield potential of cultivars such as Triton is substantially reduced because of the impairment of photosynthesis by cytoplasmic gene(s) for triazine resistance. A slight reduction in the yield of Haya with an increase in simazine concentration from 500 to 1000 ml/ha suggested that further increases in simazine concentration required for optimal weed control are likely to have a detrimental effect on the yield of Haya and other tolerant cultivars. Genetic analyses of variation in simazine tolerance in populations derived from crosses among cultivars representative of the range in tolerance indicated that the narrow-sense heritability of tolerance was of sufficient magnitude to allow for isolation of genotypes tolerant of higher simazine concentrations. These could be utilized in developing high yielding cultivars in areas of southern Australia where simazine treatment is necessary for effective weed control in Canola crops.
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  • 67
    ISSN: 1573-5060
    Keywords: Brassica napus ; fertility ; interspecific hybridization ; self-incompatibility ; somatic hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Brassica napus is a natural allotetraploid derived from the diploid species B. rapa L. (syn. campestris L.) and B. oleracea L. Somatic hybrids synthesized from highly heterozygous lines of these two diploid species were evaluated for fertility. The hybrids were obtained from two fusion experiments which differed in the B. rapa full-sibling parent used as the source of protoplasts. Both B. rapa siblings were lelf-incompatible (SI) yet contained different S-alleles; the B. oleracea species parent was self-compatible (SC). Eight tetraploid hybrids examined had very high female and male fertility; eight hybrids with higher ploidy had low fertility. Hybrids derived from one B. rapa sibling were self-incompatible, whereas those derived from the other B. rapa sibling were fully self-compatible. These data suggest that the different S-alleles of each B. rapa sibling displayed varying penetrance relative to the SC of the B. oleracea parent when combined in B. napus.
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  • 68
    ISSN: 1573-5028
    Keywords: Brassica napus ; embryogenesis ; leucine-zipper motif ; oleosin ; oil-body protein ; seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sequence of an oleosin gene from Brassica napus has been determined. This gene contains a single intron of 437 bp and encodes a polypeptide of 195 amino acids. The oleosin gene product has an estimated molecular mass of 21.5 kDa and consists of a highly hydrophobic central domain flanked by relatively polar N- and C-terminal domains. The central domain is highly conserved between all oleosins sequenced to date and contains a run of periodically spaced leucine residues similar to that of a leucine-zipper motif. The gene has been shown to be expressed specifically in the embryo, maximally between 9 and 11 weeks after flowering, i.e. during the seed desiccation stage. Two transcriptional start sites have been mapped to -70 and -21 of the ATG and a putative ABA-responsive element and three repeated motifs have been identified in the promoter. These short promoter sequences could correspond to regulatory elements responsible for embryo-specific gene expression. Up to six genes exist in the oleosin gene family.
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  • 69
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    Plant molecular biology 19 (1992), S. 1079-1083 
    ISSN: 1573-5028
    Keywords: oleosin ; embryogenesis ; cDNA ; Brassica napus ; oil-body protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antibodies raised against purified rapeseed 19 kDa oleosin protein were used to screen an embryo-derived λgt11 expression library from Brassica napus. A near full-length cDNA clone, BnV, was isolated. The 781 bp cDNA contained an open reading frame of 549 bp followed by an untranslated region of 222 pb and a poly(A) region of 10 bp. Comparisons between this cDNA and a different oleosin cDNA previously isolated from the same library showed high degrees of sequence similarity in the central domain region and in the 3′ untranslated region. Sequence similarities between the derived protein sequence of this cDNA and all other known oleosin protein sequences are discussed.
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  • 70
    ISSN: 1573-5028
    Keywords: Brassica napus ; cruciferin ; seed globulin ; storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene encoding a subunit of the 12S storage globulin, cruciferin, in Brassica napus (oilseed rape) has been isolated and characterized. The gene consists of about 2200 bp including three short intervening sequences. Primer extension analysis showed that the major transcription start site is located 30 bp 5′ of the predicted ATG start codon. This gene belongs to one of three different major families encoding cruciferin subunits. By use of gene-family-specific probes and Southern blotting analysis the number of genes of the three different cruciferin subtypes in B. napus was estimated.
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  • 71
    ISSN: 1573-5028
    Keywords: acyl-(acyl carrier protein) thioesterase ; acyl carrier protein ; Brassica napus ; fatty acid synthesis ; rape ; seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The level of two thioesterases, acyl-CoA thioesterase and acyl-ACP thioesterase was determined during seed maturation in oil seed rape. Both thioesterase activities rose markedly prior to the onset of lipid accumulation, but the induction kinetics suggest that the activities reside on distinct polypeptides. Acyl-ACP thioesterase (EC 3.1.2.14) was purified 2000-fold using a combination of ion exchange, ACP-affinity chromatogr aphy, chromatofocusing and gel filtration. Using native gel electrophoresis, and assays for enzymic activity, two polypeptides were identified on SDS-PAGE as associated with the activity. Cleveland mapping of these polypeptides, of 38 kDa component and 33 kDa respectively, demonstrated that they are related. An antibody was prepared against the 38 kDa component, and this also recognises the 33 kDa polypeptide in highly purified preparations. Western blotting of a crude extract identifies one band at 38 kDa consistent with the 33 kDa component being a degradation product generated during purification. The native molecule has a Mr of 70 kDa indicating a dimeric structure. The enzyme has a pH optimum of 9.5 and shows strong preference for oleoyl-ACP as substrate. The intact enzyme has an N-terminus blocked to protein sequencing. We also found that two other polypeptides co-purify with acyl-ACP thioesterase under native conditions. The N-terminal amino-acid sequence of these polypeptides is shown and their possible identity is discussed.
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  • 72
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    Molecular genetics and genomics 234 (1992), S. 379-389 
    ISSN: 1617-4623
    Keywords: Brassica napus ; Anther-specific ; Chalcone synthase ; RNA-PCR assay ; In situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A cDNA library of Brassica napus (cv. Westar) was constructed using poly(A)+ RNA isolated from developing anthers of flower buds 2–3 mm in length. Differential hybridization, using cDNA probes complementary to poly(A)+ RNA from developing anthers or seedlings, was used for initial screening. In addition to Southern and Northern blot analyses of selected clones, RNA-PCR assays and in situ hybridization were used to study the temporal and spatial gene regulation in anthers at the transcriptional level. Five independent cDNA clones, showing no cross-hybridization to one another, were characterized, and their expression patterns could be grouped into three distinct categories. Two cDNA clones, BA112 and BA158, are tapetum-specific: the corresponding mRNAs accumulate in young anthers and decline as the tapetum cells degenerate later in anther development. The transcripts represented by BA54 and BA73 accumulate late in anther development and reach a maximum level in mature anthers prior to anthesis; BA54 has been confirmed to be pollen-specific. The third category, represented by BA42, is found to encode a protein sharing 64–67% amino acid similarity with chalcone synthase (CHS) from various plant species; the transcript is localized in the peripheral cells of the vascular bundle, tapetum, and developing microspores.
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  • 73
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    Sexual plant reproduction 4 (1991), S. 22-27 
    ISSN: 1432-2145
    Keywords: Brassica napus ; Cytoplasmic male sterility ; Microsporogenesis ; Temperature ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Under an intermediate temperature regime (23° C/18° C; day/night), microsporogenesis in stamens of the ogu cytoplasmic male-sterile (CMS) line of Brassica napus terminated by the tetrad stage, although in some cases degeneration of the sporogenous tissue occurred prior to meiosis. In most cases the tetrads were collapsed and bounded by a sparse exine, but contained many organelles. Also, the tapetum in CMS anthers was abnormal and often highly vacuolated by the tetrad stage. Under low temperature conditions (18° C/15° C; day/night), neither microsporogenous nor tapetal tissues were observed. In the normal stamens, no differences were observed under different temperature regimes. In conjunction with the adjoining paper, this study demonstrates that temperature conditions strongly affect the cytological processes associated with microsporogenesis in the CMS anthers.
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  • 74
    ISSN: 1432-2145
    Keywords: Brassica napus ; Colchicine ; Cytoskeleton ; Microspore-embryogenesis ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An attempt has been made to manipulate the cytological processes regulating the switch from gametophytic to sporophytic development induced by culturing the microspores of higher plants. Previous studies have indicated that sporophytic development, which leads to the formation of haploid embryos, normally follows the symmetrical division of the microspore rather than the asymmetric mitosis characteristic of normal development. To determine whether symmetry of division is a key factor in the determination of subsequent development, cells were supplied with the antimicrotubule drug colchicine to disrupt elements of the microtubular cytoskeleton believed to be involved in nuclear positioning. The treatment resulted in a highly significant increase in the numbers of cells turning to sporophytic development; further, timed applications indicated that the cells were sensitive to the drug over a 12-h period immediately prior to pollen mitosis. The results suggest that alteration of division symmetry is sufficient to switch the developmental pathway from gametophytic to sporophytic. These findings are discussed in the perspective of current models proposed for the regulation of development in eukaryotic cells.
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  • 75
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    Sexual plant reproduction 4 (1991), S. 176-181 
    ISSN: 1432-2145
    Keywords: Pollen ; Brassica napus ; Mitoses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.
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  • 76
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    Sexual plant reproduction 4 (1991), S. 226-234 
    ISSN: 1432-2145
    Keywords: Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
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  • 77
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    Current genetics 19 (1991), S. 323-327 
    ISSN: 1432-0983
    Keywords: Brassica napus ; CMS ; ‘Polima’ cytoplasm ; Mitochondrial transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We report here on RFLP and Northern blot analyses of the ‘Polima’ CMS-System in Brassica napus. Mitochondrial (mt)DNA and plastid (pt)DNA data indicate that the restorer, as well as the sterile and restored plants, possess a pol cytoplasm but that the restores has no Brassica mt-plasmid. An additional substoichiometric 3.3 kb EcoRI ptDNA fragment is present in the restorer. The transcription patterns of 12 mitochondrial-encoded genes of the pol cytoplasm have been determined for male-sterile and restored plants. Transcription patterns of the atp6 gene are correlated with the nuclear background. Restorer and restored plants exhibit two additional transcripts not detectable in sterile plants.
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  • 78
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    Plant foods for human nutrition 41 (1991), S. 69-88 
    ISSN: 1573-9104
    Keywords: selenium ; nutrition ; plant spraying ; multiple use ; Helianthus tuberosus ; Medicago sativa ; Brassica napus ; polarography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.
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  • 79
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    Biology and fertility of soils 12 (1991), S. 213-216 
    ISSN: 1432-0789
    Keywords: Soil management problems ; Multiply cropped paddy fields ; Mineral fertilizer ; Organic manure ; Sustainable agriculture ; Oryza sativa ; Trificum sativa ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Multiple cropping of paddy fields has now been widely adopted in East China, in order to increase annual grain yields. The management practices recommended for these multiple cropped fields include the use of mineral fertilizers in combination with organic manure, to sustain a better soil nutrient balance, the adoption of rice-straw manuring, and use of zero or minimum tillage. This paper presents the results of a series of longterm experiments in multiple cropping and discusses the problems associated with these techniques.
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  • 80
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    Plant cell, tissue and organ culture 24 (1991), S. 43-47 
    ISSN: 1573-5044
    Keywords: Brassica napus ; protoplasts ; purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of three different general purification protocols have been assessed quantitatively using mesophyll protoplasts of Brassica napus. Within the initial sample two distinct sub-populations were determined. The methods used influenced the ratio of the vacuolated to chloroplastic type protoplast sub-populations. Overall recovery rates of the initial sample varied according to the method used from 38% to 27%, but the relative recovery of the sub-populations varied considerably with a purified ratio of between 1.0:0.78 to 1.0:7.0. Size distribution profiles of the initial and purified populations are also presented.
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  • 81
    ISSN: 1573-1561
    Keywords: Sinaibin ; glucosinolate ; resistance ; Sinapis alba ; Brassica napus ; Phyllotreta cruciferae ; Coleoptera ; Chrysomelidae ; Mamestra configurata ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Sinalbin was identified as a chemical component of insect anti-xenosis and antibiosis resistance mechanisms in seedlings ofSinapis alba by DEAE-Sephadex chromatography, HPLC, treatment with sulfatase and myrosinase, various feeding tests using artificial and natural substrates, and by measuring sinalbin concentrations in cotyledons and leaves during seedling development. The effects of sinaibin on feeding were dependent upon the insect species and upon the rapidly changing profile of sinaibin concentrations in the developing seedling. The high concentrations of sinalbin found in young cotyledons (up to 20 mM) and leaves (up to 10 mM) deterred the feeding of the flea beetle,Phyllotreta cruciferae Goeze and larvae of the bertha armyworm,Mamestra configurata Walker. The protection that sinalbin confers upon the vulnerable, newly emerged seedling (and upon tiny, young leaves) appears critical for the first few days of survival ofS. alba under feeding pressure from flea beetles in the field. The lower concentrations of sinaibin found in older cotyledons and leaves (2–3 mM) offer little or no protection againstP. cruciferae and may actually stimulate the feeding of this crucifer specialist. These concentrations of sinaibin, however, are still effective in reducing the level of feeding by larvae of the more generalist feederM. configurata.
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  • 82
    ISSN: 1573-5028
    Keywords: acetolactate synthase ; Brassica napus ; cDNA ; expression ; nucleotide sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 83
    ISSN: 1573-5028
    Keywords: Gene transfer ; Arabidopsis thaliana ; Brassica napus ; transient expression ; pneumatic particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Successful transient expression of β-glucuronidase (GUS) in Arabidopsis thaliana leaves and roots and Brassica napus stems was obtained after gene delivery with a pneumatic particle gun driven by compressed air. Effects of the pneumatic pressure used to accelerate the particles (accelerating pressure; 85 to 200 kg/cm2) and of preculture periods of plant tissues (0 to 6 days) on the efficiency of gene delivery were studied. In A. thaliana leaves, best results were obtained at 115 kg/cm2 of accelerating pressure and 3 days of preculture. In A. thaliana roots, the optimum was at 200 kg/cm2 of accelerating pressure and 3 days of preculture. These results indicate that both preculture period and accelerating pressure are vital factors that determine the efficiency of gene delivery by particle gun.
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  • 84
    ISSN: 1573-5028
    Keywords: Brassica napus ; extensin genes ; GUS gene fusions ; phloem-specific expression ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The organs and tissues where the Brassica napus extA extensin gene is expressed have been identified. The extA gene with 3.75 kb of 5′ flanking sequence was transferred to tobacco via disarmed Agrobacterium tumefaciens vectors and transgenic plants regenerated. The gene was found to be inactive in transgenic tobacco leaf, but was active as measured by RNA transcript assays in both stem and root tissues. To determine the cell-specific expression pattern of the extA gene, a promoter-reporter gene fusion construct was made consisting of 1.0 kb of 5′ extA sequence fused to the coding region of the glucuronidase (GUS) gene. This fusion construct was introduced into B. napus via Agrobacterium rhizogenes, and expression of GUS in transgenic rape hairy roots was examined. GUS activity was only seen in the vascular tissues of the rape root, and was found to be specifically localised in the phloem.
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  • 85
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    Plant molecular biology 17 (1991), S. 1-8 
    ISSN: 1573-5028
    Keywords: Agrobacterium rhizogenes ; Brassica napus ; genetic transformation ; hairy roots ; regenerated shoots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetically transformed root clones of rapeseed (Brassica napus) were obtained afterin vitro infection of excised hypocotyl segments with a wild type strain ofAgrobacterium rhizogenes and two strains ofA. rhizogenes harbouring kanamycin resistance. The ability of hairy root formation was affected by light and was highly dependent on the location of the infection site at the hypocotyl. Inoculation of decapitated hypocotyls with an intact root system gave rise to direct shoot formation from the site of inoculation. Histological sections showed that several meristems were initiated at the inoculation site. Root and shoot clones were isolated and subcultured axenically in hormone-free liquid MS medium. Identification of transformed root and shoot clones was based on opine assays. Further selection was carried out in kanamycin-enriched medium. All opine-positive root clones showed NPT II (neomycin phosphotransferase) activity. Nearly half of the shoot clones expressed a strong NPT II activity while the rest gave a weak or no NPT II response.
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  • 86
    ISSN: 1573-5060
    Keywords: Brassica napus ; donor plant age ; embryogenesis ; haploid ; microspore culture ; microspore stage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Effect of age of donor plants and age of inflorescence on embryogenesis in microspore culture of B. napus was examined. Microspores isolated from buds of older plants had a higher embryo yield than those of younger ones. The effect of the age of inflorescence showed a different pattern. In older plants, a higher embryogenesis response was observed in microspores isolated from buds of new inflorescences, while in young plants, microspores isolated from buds of old inflorescences showed high embryo yield. These different responses were considered to be attributable to a difference in the developmental stage of pollen at the time of microspore isolation. Our results indicated that microspores collected from older inflorescences and older plants have sufficient embryogenic potential when the optimum developmental stage of pollen was used. Frequency of embryo to plant conversion was influenced by the size of embryos subcultured, but not by donor plant age or the age of the inflorescence.
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  • 87
    ISSN: 1573-5060
    Keywords: Brassica napus ; rapeseed fatty acid accumulation ; microspore-derived embryo ; zygotic seed ; triacylglyceride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Microspore culture of rapeseed (Brassica napus L.) has provided a powerful tool not only for breeding but also in developmental studies. In this study, microspore-derived embryos (MDE) of B. napus were evaluated as a model in seed for studying accumulations of triacylglyceride (TAG) fatty acids in both a low and high erucic acid rapeseed line; and accumulations of TAG and free fatty acids (FFA) in a high erucic acid rapessed line. The accumulation patterns confirmed that MDE had a similar TAG fatty acid profile to seed during the embryo development within each genotype. The oil accumulation in MDE after 36 days in culture (DIC) approached levels similar to those in zygotic seed 25 days after flowering (DAF). Significant differences were detected in contents of both total free fatty acids and specific free fatty acids between MDE and seed. During the developmental period, total free fatty acids changed from 16% to 2.1% in MDE, but from 10.5% to 0.1% in seed. MDE had much higher percentage of free linolenic and erucic acids than seed, particularly during the late developmental stages. The current study indicated that MDE can be used as a model to study TAG and TAG fatty acids in seed but caution must be taken to study free fatty acid metabolism.
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    Plant cell, tissue and organ culture 26 (1991), S. 195-201 
    ISSN: 1573-5044
    Keywords: Brassica napus ; cell culture ; diffusion ; liquid medium ; oxygen availability ; protoplast culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method for estimating the oxygen availability in plant cell cultures grown in stationary liquid media (e.g. many protoplast cultures) was developed. The method is based on short-term measurements of respiration rate versus oxygen concentration on a sample of cells, suspended in liquid media. From such data it is possible to estimate the oxygen concentration at the bottom of a stagnant liquid culture, by calculating the amount of oxygen reaching the cells by diffusion. As an example, rape (Brassica napus L. cv. Omega) hypocotyl protoplasts were grown with different oxygen concentrations at the site of the cells, obtained by varying the cell density, the height of the liquid layer and the oxygen content of the gas phase. The number of surviving calli was positively correlated with the estimated oxygen availability in the range between 60 and 350 μM O2, below 60 μM all cells died. This indicates that oxygen availability can be a limiting factor in the range usually encountered in protoplast cultures, and that the method can be useful when designing optimal growth conditions for stationary cultures of plant cells.
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  • 89
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    Euphytica 58 (1991), S. 31-35 
    ISSN: 1573-5060
    Keywords: Brassica napus ; SSD lines ; heterosis ; epistasis ; yield ; quality traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Heterosis and epistasis in spring oilseed rape (Brassica napus L.) was analysed by comparing generation means for ten agronomic traits. Parents, F2, F3 and F6 generations of four crosses with Swedish and French material were investigated. The F2 was 11% higher in yield, earlier in flowering time, and slightly later in maturation when compared with the parents. Randomly derived single seed descent lines had an 8% lower yield, were later flowering and maturing than the parents in F6. This poorer average performance of recombinant lines is explained by the loss of favourable epistatic interactions present in the parents.
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  • 90
    ISSN: 1573-5028
    Keywords: Brassica napus ; microscope development ; pectin esterase ; pollen-specific gene ; promoter sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Differential screening of a Brassica napus genomic library led to the isolation of the clone named Bp 19 containing a gene which is highly expressed during microspore development. The accumulation of Bp 19 mRNA starts in uninucleate microspores, increases during development reaching a peak in the late stages but declines considerably in mature pollen. The nucleotide sequence of the entire coding region and of extended portions of the 5′ and 3′ flanking regions was determined. Several homologous cDNA clones were also isolated and sequenced. The Bp 19 gene contains a single intron of 137 bp and gives origin to a mRNA of ca. 1.9 kb which codes for a polypeptide of 584 amino acids. Bp 19 protein has an estimated molecular weight of 63 kilodaltons and has a highly hydrophobic amino terminal region which shows features of a signal peptide. The carboxy half of the Bp 19 protein, starting at amino acid 269, has striking sequence similarity to the pectin esterases of tomato and of the plant pathogen Erwinia chrysanthemi. Four short domains are extremely well conserved in all the three proteins and therefore could represent catalytic sites responsible for enzyme activity. Comparison of the 5′ flanking region of the Bp 19 gene with the sequence of other pollen-specific promoters revealed the presence of several conserved regions. These short promoter sequences could correspond to regulatory elements responsible for pollen-specific gene expression.
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  • 91
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    Plant molecular biology 17 (1991), S. 295-299 
    ISSN: 1573-5028
    Keywords: Brassica napus ; microspore-specific ; microsporogenesis ; DNA sequence ; peptide motif
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The I3 cDNA isolated from a library made from 2–4 mm (immature) anthers of Brassica napus shows microspore-specific expression. Homologous transcripts are detected in buds and anthers of male-fertile plants, but not in green tissues, roots, or in cytoplasmic male-sterile buds. High expression of the transcript is limited to microspores entering and undergoing mitosis. The predicted peptide sequence of the cDNA shows an unusual repeated alanine/proline motif at the C-terminus, which may be of importance in the native protein structure.
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  • 92
    ISSN: 1573-5028
    Keywords: Brassica napus ; embryogenesis ; napin gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract S1 nuclease analysis and sub-family-specific oligonucleotide probes were used to characterize the expression during embryogenesis of the napin storage protein gene family ofBrassica napus (oilseed rape). The expression of one sub-class represented by the napin gene gNa peaks and declines earlier than the other members of the family. This sub-class was highly expressed representing ca. 20% of napin mRNA at 26 days after anthesis.
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  • 93
    ISSN: 1573-5028
    Keywords: Brassica napus ; DNA-binding proteins ; light-inducible gene ; tissue specificity ; transmembrane protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using a fractionated genomic bank, we have cloned and characterized a Brassica napus gene (rbcSF1) encoding the small sub-unit of ribulose 1,5-bisphosphate carboxylase. The promoter of this gene contains a 29 bp direct repeat capable of forming a single or a double hairpin loop, and three elements that are recognized by leaf nuclear proteins in vitro. The most upstream are the S-box, a small A/T-rich sequence between −516 and −512, and the F-box between −492 and −475. Finally, we have also observed binding to the G-box, a regulatory element common to numerous plant promoters. The promoter of rbcSF1 also has a 113 amino acids open reading frame (ORF113) in the non-coding strand. When used to probe a northern blot of leaf RNA, this ORF hybridizes to a 1.5 kb transcript. The protein encoded by ORF113 contains a transmembrane domain.
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  • 94
    ISSN: 1573-5028
    Keywords: acyl carrier protein ; Brassica napus ; enoyl-ACP reductase ; fatty acid synthesis ; seed development ; nuclear-encoded chloroplast proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The onset of storage lipid biosynthesis during seed development in the oilseed crop Brassica napus (rape seed) coincides with a drastic qualitative and quantitative change in fatty acid composition. During this phase of storage lipid biosynthesis, the enzyme activities of the individual components of the fatty acid synthase system increase rapidly. We describe a rapid and simple purification procedure for the plastidlocalized NADH-dependent enoyl-acyl carrier protein reductase from developing B. napus seed, based on its affinity towards the acyl carrier protein (ACP). The purified protein was N-terminally sequenced and used to raise a potent antibody preparation. Immuno-screening of a seed-specific λgt11 cDNA expression library resulted in the isolation of enoyl-ACP reductase cDNA clones. DNA sequence analysis of an apparently full-length cDNA clone revealed that the enoyl-ACP reductase mRNA is translated into a precursor protein with a putative 73 amino acid leader sequence which is removed during the translocation of the protein through the plastid membrane. Expression studies in Escherichia coli demonstrated that the full-length cDNA clone encodes the authentic B. napus NADH-dependent enoyl-ACP reductase. Characterization of the enoyl-ACP reductase genes by Southern blotting shows that the allo-tetraploid B. napus contains two pairs of related enoyl-ACP reductase genes derived from the two distinct genes found in both its ancestors, Brassica oleracea and B. campestris. Northern blot analysis of enoyl-ACP reductase mRNA steady-state levels during seed development suggests that the increase in enzyme activity during the phase of storage lipid accumulation is regulated at the level of gene expression.
    Type of Medium: Electronic Resource
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  • 95
    ISSN: 1432-203X
    Keywords: Brassica napus ; microspore ; density ; conditioned medium ; feeder ; embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In microspore cultures of Brassica napus L. cv. Topas, embryo yield increases with culture density up to about 40,000 microspores per ml. A much higher density (100,000 per ml) appears inhibitory to embryogenesis. A relatively high culture density (30,000 or 40,000 per ml) for the first 2–4 days of culture is crucial for embryogenesis, after which cultures may be diluted to allow better embryo growth. Medium conditioned by culturing microspores at 30,000 or 40,000 per ml for 1 day improved microspore-embryo yield in low density cultures (3,000 or 4,000 per ml) more than 3-fold. In contrast, media conditioned with microspores from 1–4 days or 0–4 days of culture were inhibitory. Use of feeder cultures resulted in up to 10-fold increase of embryo yield in low density microspore cultures, depending on the method used. Filter papers and other membranes placed on top of feeders greatly inhibited embryogenesis in the feeder layer as well as microspores cultured on the feeder, possibly due to poorer gaseous exchange.
    Type of Medium: Electronic Resource
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  • 96
    ISSN: 1432-2242
    Keywords: Brassica napus ; Transgenic ; Acetohydroxyacid synthase ; Sulfonylurea ; Imidazolinone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A survey of selected crop species and weeds was conducted to evaluate the inhibition of the enzyme acetohydroxyacid synthase (AHAS) and seedling growth in vitro by the sulfonylurea herbicides chlorsulfuron, DPX A7881, DPX L5300, DPX M6316 and the imidazolinone herbicides AC243,997, AC263,499, AC252,214. Particular attention was given to the Brassica species including canola cultivars and cruciferous weeds such as B. kaber (wild mustard) and Thlaspi arvense (stinkweed). Transgenic lines of B. napus cultivars Westar and Profit, which express the Arabidopsis thaliana wild-type AHAS gene or the mutant gene csr1-1 at levels similar to the resident AHAS genes, were generated and compared. The mutant gene was essential for resistance to the sulfonylurea chlorsulfuron but not to DPX A7881, which appeared to be tolerated by certain Brassica species. Cross-resistance to the imidazolinones did not occur. The level of resistance to chlorsulfuron in transgenic canola greatly exceeded the levels that were toxic to the Brassica species or cruciferous weeds. Direct selection of transgenic lines with chlorsulfuron sprayed at field levels under greenhouse conditions was achieved.
    Type of Medium: Electronic Resource
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  • 97
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 80 (1990), S. 465-469 
    ISSN: 1432-2242
    Keywords: Microspore-derived population ; Fatty acids ; Inheritance ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The inheritance of major fatty acids in seed triglycerides was studied in three homozygous microspore-derived populations of spring rapeseed (Brassica napus L.). Crosses were made among parents with contrasting amounts of erucic, oleic, linoleic and linolenic acids. Microspores from F1 plants were cultured, and haploid plants were colchicine-doubled to provide homozygous populations reflecting F1 gametic arrays for fatty acid genotypes. Segregation ratios of the gametic arrays for specific fatty acid contents were compared to hypothetical models by the Chi-square test. Segregation pattern confirmed that erucic acid levels were controlled by two major loci, each having two alleles with additive effects. Oleic acid segregation indicated control of accumulation by at least two segregating genetic systems, one acting on chain elongation and the other involving desaturation. Accumulations of erucic acid and oleic acid were influenced by the same two loci, which control the chain elongation steps leading from oleic acid to erucic acid. Oleic acid was further influenced by at least two additional segregating loci involved in control of desaturation of oleic acid to form linoleic acid. Segregating alleles at loci involved in desaturation had a much smaller influence on oleic acid content than alleles segregating at loci controlling, the elongation of oleic acid to erucic acid. In a population free of erucic acid, the segregation pattern of linoleic acid levels fit a model involving segregating alleles at two loci. In contrast, segregation for linolenic acid content fits a three-locus additive model. In this study, microspore culture technology provided a rapid method of defining F1 gametic segregation for inheritance analyses.
    Type of Medium: Electronic Resource
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  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 3 (1990), S. 263-276 
    ISSN: 1432-2145
    Keywords: Brassica napus ; Cytoplasmic male sterility ; Microsporogenesis ; Temperature ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the ogu cytoplasmic male-sterile (CMS) line of Brassica napus, stamen morphology was influenced by temperature conditions. Under a high temperature regime (27° C/23° C; day/ night) CMS stamens had a near-normal morphology, but microsporogenesis proceeded to a maximum of the microspore stage. However, compared to the normal stamens, the occurrence of sporopollenin-like deposits in the tapetum and deposition of exine on the microspores was sparse. Also, the tapetal cells of the CMS line were often highly vacuolate and failed to degenerate at the same stage as the normal. Ultrastructural changes in the mitochondrial matrix and cristae plus dilation of the endoplasmic reticulum, which occurred during development in sporogenous tissues of the normal line, were often lacking or mistimed in the mutant. Due to extensive variation, even between adjacent locules, the cytological differences between the normal and CMS anthers cannot be ascribed as the cause of male sterility in the ogu CMS line of B. napus, rather they may be the consequence of it.
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell, tissue and organ culture 22 (1990), S. 21-26 
    ISSN: 1573-5044
    Keywords: Brassica napus ; differential thermal analysis ; frost resistance ; leaf disk culture ; leaf senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Disks were isolated from young leaves of winter rape plants and grown in vitro at ambient (15°C) or low (2°C) temperatures for two weeks. In the control disks the growth cessation and beginning of chlorophyll degradation were observed after 1 week of culture. In the low-temperature treated disks the expansion of cells was slower than that in the control material but it continued for two weeks and was accompanied by a marked accumulation of dry matter. Practically, no chlorophyll degradation was observed. The low temperature treatment brought about the decrease in the frost killing temperature of the tissue which was associated with its increased capacity to subcool water. A short (18 h) exposure of the cold-grown leaf disks to slight frost (−5°C) increased further their resistance to freezing, despite the fact that the subcooling capacity of disks decreased in result of the treatment. Therefore, the two stages of hardening, observed previously for the whole plants, can also be detected in the isolated material. In the cold-grown disks, a transient accumulation of reducing sugars but a steady decrease in ATP and water-soluble protein contents were observed. These observations indicate that tissue isolation might affect processes involved in the functional adaptation of cells to cold.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell, tissue and organ culture 23 (1990), S. 187-192 
    ISSN: 1573-5044
    Keywords: Brassica napus ; chilling ; desiccation ; haploid embryos ; microspore-derived embryos ; rapeseed ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Germination was readily induced in recalcitrant microspore-derived embryos of Brassica napus ‘Topas’ when they were exposed to a period of chilling (9–12 days at 4°C) or partial desiccation (rapid or slow air drying) prior to germination. In general, embryos thirty-five days old had the highest germination rates as compared to younger or older ones. Populations of embryos were induced to germinate at a rate of over 90% under specific temperature, desiccation and age conditions. Comparisons to an embryogenic B. napus winter line, F346, are made.
    Type of Medium: Electronic Resource
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