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  • 1
    Digitale Medien
    Digitale Medien
    Expression of a cassava granule-bound starch synthase gene in the amylose-free potato only partially restores amylose content (1999)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 22 (1999), S. 0 
    Details
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Granule-bound starch synthase I (GBSS I) is responsible for the synthesis of amylose in starch granules. A heterologous cassava GBSS I gene was tested for its ability to restore amylose synthesis in amylose-free (amf) potato mutants. For this purpose, the cassava GBSS I was equipped with different transit peptides. In addition, a hybrid containing the potato transit peptide, the N-terminal 89 amino acids of the mature potato GBSS I, and the C-terminal part of cassava GBSS I was prepared. The transgenic starches were first analysed by iodine staining. Only with the hybrid could full phenotypic complementation of the amf mutation be achieved in 13% of the plants. Most transformants showed partial complementation, but interestingly the size of the blue core was similar in all granules derived from one tuber of a given plant. The amylose content was only partially restored, up to 60% of wild-type values or potato GBSS I-complemented plants; however, the GBSS activity in these granules was similar to that found in wild-type ones. From this, and the observation that the hybrid protein (a partial potato GBSS I look-alike) performs best, it was concluded that potato and cassava GBSS I have different intrinsic properties and that the cassava enzyme is not fully adapted to the potato situation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3040.1999.00493.x
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  • 2
    Digitale Medien
    Digitale Medien
    Gene expression and carbohydrate content during stolon to tuber transition in potatoes (Solanum tuberosum) (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 90 (1994), S. 0 
    Details
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: In using an efficient and synchronised in vitro tuberisation system the transition of axillary buds from stolons to tubers in Solanum tuberosum L. cv. Bintje was followed. After 5 or 6 days on tuber-inducing medium all axillary buds had formed tubers which increased in size until the experiment was ended at day 10. Concomitantly with the visible appearance of tubers the fresh weight of the axillary buds increased as well as their starch content. Soluble sugar content, notably glucose, increased until tuberisation occurred and dropped after that. In the daily sampled explants gene expression was studied at several levels. RNA was isolated from the different explants during the whole tuberisation experiment and northern blots were probed with cDNAs encoding genes involved in starch- and patatin-biosynthesis. It was shown that in the very early stages of development hardly any transcript could be detected. Only one day before visible swelling occurred were clear signals obtained for all the genes investigated. Although it was evident that coordinate expression of starch biosynthetic genes did occur, it was not in a similar fashion for all the genes. Sucrose synthase and ADPG-pyrophosphorylase B were expressed in an identical fashion which was different from ADPG-pyrophosphorylase S, granule-bound starch synthase and branching enzyme. The RNA levels of these three latter genes reached a maximum at day 5, remaining constant until the experiment was finished. The transcript levels of sucrose synthase and ADPG-pyrophosphorylase B reached their highest level at day 5 after which they dropped to a lower level at day 10. Patatin gene expression was clearly different from that of the starch biosynthetic genes: it steadily increased from day 4 until the end of the experiment. Enzyme activities of sucrose synthase. ADPG-pyrophosphorylase and branching enzyme confirmed the RNA expression data and showed that ADPG-pyrophosphorylase enzyme activity reached a maximum at day 4 after which it dropped. The other two enzyme activities could be detected at or one day after tuberisation occurred and increased until the experiment was ended.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1399-3054.1994.tb00389.x
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  • 3
    Digitale Medien
    Digitale Medien
    Nodule physiology of a supernodulating pea mutant (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 77 (1989), S. 0 
    Details
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Physiological and biochemical parameters of the supernodulating pea (Pisum sativum L.) mutant nod3 were compared to those of its wild-type parent cv. Rondo in a nil nitrate environment. Plants of cv. Rondo produced more biomass and accumulated more N than plants of nod3. Accordingly, seed yield of the wild type was twice that of the supernodulating mutant. Although the nodule number of nod3 was 10-fold that of cv. Rondo, the nodule mass of nod3 was only twice that of cv. Rondo as individual nodules were smaller in nod3 than in cv. Rondo. The maximum rate of acetylene reduction activity, determined in an open flow-through gas system, was higher in the wild type than in nod3 when expressed on a nodule dry weight basis. However, when expressed on a whole plant basis, the nitrogenase activity (acetylene reduction) was similar in the two symbioses. The net carbon costs of nitrogenase activity was 25% lower in nod3 than in cv. Rondo. An equal proportion of the net CO2 efflux from the root system was for growth and maintenance of the tissue in the two symbioses. However, growth and maintenance respiration was higher in nod3 than in cv. Rondo per gram dry weight of the nodulated root system. The nodules of nod3 had a reduced soluble protein concentration as compared to those of the wild type. The specific activities of nodule glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 1.4.1.14) and asparagine synthetase (EC 6.3.5.4) were lower in nod3 than in cv. Rondo. The root bleeding sap of nod3 contained lower amounts of glutamine and higher amounts of asparagine than that of cv. Rondo. The results suggest that the use of carbon directly related to the dinitrogen fixation and nitrogen assimilation may be less in nod3 than in cv. Rondo, and that there may be differences between the two symbioses in the pathway for assimilation of fixed nitrogen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1399-3054.1989.tb05398.x
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  • 4
    Digitale Medien
    Digitale Medien
    Successful first and second backcrosses of S. nigrum (+) S. tuberosum somatic hybrids with both Solanum parents (1999)
    Springer
    Sexual plant reproduction 12 (1999), S. 144-151 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Key words Solanum tuberosum ; Solanum nigrum ; Somatic hybrids ; Backcross experiments ; Phytophthora infestans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Somatic hybrids of Solanum nigrum (+) 2× potato were successfully crossed with S. nigrum and with potato. First and second backcross progeny with S. nigrum could easily be obtained. One of the BC1 genotypes was already self-fertile. Backcrosses with potato had a much lower success rate. Only pollinations with tetraploid potato resulted in seed-containing berries. Two BC1 genotypes were obtained after 4362 pollinations from which 505 ovules were cultured. The first BC1 genotype grew vigorously in vitro and in the greenhouse and flowered abundantly. The second BC1 showed many abnormalities and dropped its flowers before anthesis. The first BC1 was again crossed with tetraploid potato and in this generation also the success rate was low. Over 5000 pollinations resulted in 1750 berries from which over 3000 ovules were obtained. Twelve plants germinated from these ovules and they were not as vigorous in vitro and in vivo as the BC1 parent. Some of the BC2 genotypes were used for further backcrosses but no BC3 plants were obtained. BC1 and BC2 genotypes that resulted from the backcross program with potato were tested for resistance to Phytophthora infestans. The BC1 genotype was as resistant as the S. nigrum fusion parent, but among the eight BC2 genotypes scored six were resistant, whereas two genotypes showing lesions were susceptible.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004970050185
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  • 5
    Digitale Medien
    Digitale Medien
    Do cisgenic plants warrant less stringent oversight? (2006)
    [s.l.] : Nature Publishing Group
    Nature biotechnology 24 (2006), S. 753-753 
    Details
    ISSN: 1546-1696
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: [Auszug] To the editor: While the debate continues on the appropriate level of regulatory oversight for transgenic plants, we believe there are strong reasons for legislators to differentiate cisgenic from transgenic plants. A cisgenic plant is a crop plant that has been genetically modified with one or ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/nbt0706-753
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  • 6
    Digitale Medien
    Digitale Medien
    The extent and position of homoeologous recombination in a distant hybrid of Alstroemeria: a molecular cytogenetic assessment of first generation backcross progenies (1999)
    Springer
    Chromosoma 108 (1999), S. 52-63 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract.  To estimate the extent and position of homoeologous recombination during meiosis in an interspecific hybrid between two distantly related Alstroemeria species, the chromosome constitution of six first generation backcross (BC1) plants was analysed using sequential fluorescent in situ hybridization (FISH) and genomic in situ hybridization (GISH) analysis. Four different probes were used for the FISH analysis: two species-specific and two rDNA probes. The six BC1 plants were obtained from crosses between the hybrid A. aurea×A. inodora with its parent A. inodora. GISH clearly identified all chromosomes of both parental genomes as well as recombinant chromosomes. The sequential GISH and FISH analysis enabled the accurate identification of all individual chromosomes in the BC1 plants, resulting in the construction of detailed karyotypes of the plants. The identification of the recombinant chromosomes provided evidence which chromosomes of the two species are homoeologous. Two of the BC1 plants were aneuploid (2n=2x+1=17) and four triploid (2n=3x=24), indicating that both n and 2n gametes were functional in the F1 hybrid. Using GISH, it was possible to estimate homeologous recombination in two different types of gametes in the F1 hyrid. The positions of the crossover points ranged from highly proximal to distal and the maximum number of crossover points per chromosome arm was three. Compared with the aneuploid plants, the triploid plants (which received 2n gametes) clearly possessed fewer crossovers per chromosome, indicating reduced chromosome pairing/recombination prior to the formation of the 2n gametes. Besides homeologous recombination, evidence was found for the presence of structural rearrangements (inversion and translocation) between the chromosomes of the parental species. The presence of the ancient translocation was confirmed through FISH analysis of mitotic and meiotic chromosomes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004120050351
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  • 7
    Digitale Medien
    Digitale Medien
    Identification and mapping of three flower colour loci of potato (S. tuberosum L.) by RFLP analysis (1993)
    Springer
    Theoretical and applied genetics 86 (1993), S. 295-300 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Solanum tuberosum ; Allelism ; RFLP map ; Anthocyanin markers ; Tester clones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The inheritance of flower colour in diploid potato (2 n = 2x = 24), was found to be controlled by three unlinked loci D, F and P. To determine the allelism with previously described loci and to dissect this oligogenic trait, a set of tester clones with well-defined genotypes was developed. By backcrossing the mapping population with these tester clones it was possible to obtain monogenic segregation ratios. These were required to detect linkage with RFLP loci and, despite distorted Mendelian ratios, the inheritance and mapping of the D, F and P loci could be unambiguously determined. Locus D, involved in the biosynthesis of red anthocyanins, was mapped on chromosome 2, while locus P, involved in the production of blue anthocyanins, was mapped on chromosome 11. Locus F, involved in the flower-specific expression of gene(s) accommodated by the D and P loci, was mapped on chromosome 10. The tester clones and the map position of the D, F and P loci may be of considerable value in simplifying the genetics of anthocyanin pigmentation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222091
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  • 8
    Digitale Medien
    Digitale Medien
    Race specific resistance against Phytophthora infestans in potato is controlled by more genetic factors than only R-genes (1996)
    Springer
    Euphytica 90 (1996), S. 331-336 
    Details
    ISSN: 1573-5060
    Schlagwort(e): potato ; Solanum tuberosum ; Phytophthora infestans ; R-genes ; suppressor ; late blight
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary For RFLP mapping of R-genes, determining resistance to specific races of Phytophthora infestans in tetraploid potato, it is necessary to develop well segregating populations at the 2x level. During mapping studies, evidence was obtained that more genetic factor(s) are involved in the expression of R-genes than conventionally believed. Two experiments are described in which such an additional genetic factor was suppressing or enhancing the expression of unknown R nand R ifactors. R nand R iappeared to be present in the investigated plant material, containing R4 and R10, or in one of the susceptible crossing parents. In a third experiment, the expression and the segregation of the well known R1 gene was influenced by an additional genetic factor. In that case there were indications for a dominant suppressor. This was established by the selection of susceptible plants carrying a RFLP allele of probe GP21 closely linked to R1. In three of the four F1 populations, resulting from crosses between such susceptible plants and susceptible tester plants, resistnat progenies were found. The resistance appeared to be R1-specific. This clearly indicates that in three of the four investigated susceptible plants, the R1 gene was still present but not expressed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027484
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  • 9
    Digitale Medien
    Digitale Medien
    Expression of a chimaeric granule-bound starch synthase-GUS gene in transgenic potato plants (1991)
    Springer
    Plant molecular biology 17 (1991), S. 691-699 
    Details
    ISSN: 1573-5028
    Schlagwort(e): chimaeric gene ; granule-bound starch synthase ; sugar inducibility ; Solanum tuberosum L. ; transgenic plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Granule-bound starch synthase is the key enzyme in amylose synthesis. The regulation of this gene was investigated using a chimaeric gene consisting of a 0.8 kb 5′ upstream sequence of the granule-bound starch synthase gene from potato and the β-glucuronidase gene which was introduced into potato using an Agrobacterium tumefaciens binary vector system. The chimaeric gene was highly expressed in stolons and tubers, whereas the expression in leaves, stems or roots from greenhouse-grown plants was relatively low. However, leaves from in vitro grown plantlets exhibited an elevated GUS expression. The expression of the chimaeric gene was inducible in leaves by growth on relatively high concentrations of sucrose, fructose and glucose and was about 30- to 50-fold higher than in leaves from greenhouse-grown plants. The granule-bound starch synthase gene is expressed organ-specifically since stolons and tubers showed GUS activities 125- to 3350-fold higher than in leaves. The activities in these two organs are 3- to 25-fold higher than the expression of the CaMV-GUS gene. Histochemical analysis of different tissues showed that only certain regions of leaves and roots express high GUS activities. Stolons and tubers show high expression.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00037054
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  • 10
    Digitale Medien
    Digitale Medien
    Field evaluation of transgenic potato plants expressing an antisense granule-bound starch synthase gene: increase of the antisense effect during tuber growth (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1759-1773 
    Details
    ISSN: 1573-5028
    Schlagwort(e): antisense RNA ; field trial ; granule-bound starch synthase ; Solanum tuberosum L. ; transgenic plants ; tuber development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transgenic plants of a tetraploid potato cultivar were obtained in which the amylose content of tuber starch was reduced via antisense RNA-mediated inhibition of the expression of the gene encoding granule-bound starch synthase (GBSS). GBSS is one of the key enzymes in the biosynthesis of starch and catalyses the formation of amylose. The antisense GBSS genes, based on the full-length GBSS cDNA driven by the 35S CaMV promoter or the potato GBSS promoter, were introduced into the potato genome by Agrobacterium tumefaciens-mediated transformation. Expression of each of these genes resulted in the complete inhibition of GBSS gene expression, and thus in the production of amylose-free tuber starch, in mature field-grown plants originating from rooted in vitro plantlets of 4 out of 66 transgenic clones. Clones in which the GBSS gene expression was incompletely inhibited showed an increase of the extent of inhibition during tuber growth. This is likely to be due to the increase of starch granule size during tuber growth and the specific distribution pattern of starch components in granules of clones with reduced GBSS activity. Expression of the antisense GBSS gene from the GBSS promoter resulted in a higher stability of inhibition in tubers of field-grown plants as compared to expression from the 35S CaMV promoter. Field analysis of the transgenic clones indicated that inhibition of GBSS gene expression could be achieved without significantly affecting the starch and sugar content of transgenic tubers, the expression level of other genes involved in starch and tuber metabolism and agronomic characteristics such as yield and dry matter content.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019490
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