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  • 1
    Electronic Resource
    Electronic Resource
    Plant-inducible virulence promoter of the Agrobacterium tumefaciens Ti plasmid (1984)
    [s.l.] : Nature Publishing Group
    Nature 312 (1984), S. 564-566 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To investigate the promoter activity of the virC gene, we constructed plasmid pMP30 (Fig. 1), which contains the complete lacZ gene of E. coli coding for /3-galactosidase (EC 3.2.1.23), including the translational start signals, but lacks the lacP-lacO regulatory sequences. E. coli strains ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/312564a0
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  • 2
    Electronic Resource
    Electronic Resource
    Mass-spectrometric quantitation of cytokinins in tobacco crown-gall tumours induced by mutated octopine Ti plasmids of Agrobacterium tumefaciens (1988)
    Springer
    Planta 176 (1988), S. 230-234 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin in tumors ; Cytokinin (in tumors, turnover, oxidase) ; Mutant (T-DNA) ; Nicotiana (crown gall) ; T-DNA mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The levels of the major cytokinins, zeatin, zeatin riboside, zeatin riboside-5′-monophosphate and zeatin-7-glucoside were measured in tobacco (Nicotiana tabacum L.) crown-gall tissues carrying insertion and deletion mutations in the T-DNA. Measurements were made by combined gas chromatography-mass spectrometry using selected ion monitoring with 15N- and 2H-labelled internal standards. The results demonstrate that, relative to wild-type tumour tissue, cytokinin levels are considerably elevated in tissues lacking functional T-DNA auxin-biosynthetic genes. From a detailed analysis of the major cytokinin metabolites it is concluded that a reduction in the extent of cytokinin degradation via N6-side-chain cleavage is an important factor leading to increased cytokinin levels in these tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392449
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  • 3
    Electronic Resource
    Electronic Resource
    Auxin rapidly down-regulates transcription of the tryptophan decarboxylase gene from Catharanthus roseus (1992)
    Springer
    Plant molecular biology 18 (1992), S. 1113-1120 
    Details
    ISSN: 1573-5028
    Keywords: auxin ; Catharanthus roseus ; gene regulation ; indole alkaloids ; tryptophan decarboxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzyme trytophan decarboxylase (TDC) (EC 4.1.1.28) converts tryptophan into tryptamine, and thereby channels primary metabolites into indole alkaloid biosynthesis. The production of these secondary metabolites in suspension cells of Catharanthus roseus depends on medium composition. Of the possible variables, we investigated the effect of hormones on the expression of the tdc gene in cell cultures. Omission of NAA from the growth medium resulted in accumulation of tdc mRNA. The addition of 1-naphthaleneacetic acid (NAA), indoleacetic acid (IAA) or 2,4-dichlorophenoxyacetic acid (2,4-D) rapidly reduced the enhanced tdc transcript level. Cytokinin was unable to suppress the enhanced transcript level. Hairy roots transformed by Agrobacterium rhizogenes also showed a reduction of the tdc mRNA level after NAA addition. Run-off transcription experiments showed that the down-regulation takes place at the transcriptional level within 15 minutes and independent of de novo protein synthesis. Thus one of the mechanisms which control the activity of terpenoid indole alkaloid biosynthesis in C. roseus cell cultures is the negative regulation by auxin of the gene involved in the first committed step.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047714
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  • 4
    Electronic Resource
    Electronic Resource
    Transient and stable expression ofgusA fusions with rice genes in rice, barley and perennial ryegrass (1993)
    Springer
    Plant molecular biology 22 (1993), S. 1101-1127 
    Details
    ISSN: 1573-5028
    Keywords: transformation ; promoters ; introns ; gene expression ; Oryza sativa ; Hordeum vulgare ; Lolium perenne
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcriptional and translational fusions were made between the reading frame coding for β-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. TheGOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused togusA. ThegusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to theGOS2 constructs was found in stably transformed rice callus. ThegusA fusions with the mannopine synthase promoters 1′ and 2′ of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of theGOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028980
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  • 5
    Electronic Resource
    Electronic Resource
    Transient and stable expression of gusA fusions with rice genes in rice, barley and perennial ryegrass (1993)
    Springer
    Plant molecular biology 23 (1993), S. 643-669 
    Details
    ISSN: 1573-5028
    Keywords: transformation ; promoters ; introns ; gene expression ; Oryza sativa ; Hordeum vulgare ; Lolium perenne
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcriptional and translational fusions were made between the reading frame coding for β-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. The GOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused to gusA. The gusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to the GOS2 constructs was found in stably transformed rice callus. The gusA fusions with the mannopine synthase promoters 1′ and 2′ of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of the GOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021522
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  • 6
    Electronic Resource
    Electronic Resource
    Tobacco genes encoding acidic and basic isoforms of pathogenesis-related proteins display different expression patterns (1990)
    Springer
    Plant molecular biology 14 (1990), S. 119-126 
    Details
    ISSN: 1573-5028
    Keywords: β-1,3-glucanase mRNA ; chitinase mRNA ; cytokinin ; ethylene ; pathogenesis-related mRNAs ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The induction by cytokinin stress and ethylene of nine different tobacco mosaic virus-inducible mRNA classes (termed A-I) encoding pathogenesis-related (PR) proteins was studied. The induced mRNA levels were compared to basal levels in healthy tobacco plants grown in tissue culture and in a greenhouse. Cytokinin stress and ethylene were found to induce different subsets of the mRNAs, indicating that ethylene is not the primary inducing signal in cytokinin-stressed shoots. mRNAs F, H and G encoding the basic hydrolytic enzymes chitinase, β-1,3-glucanase and a basic equivalent of PR-1, respectively, were found to be expressed at high levels in roots of healthy plants. mRNAs D, I and B encoding the acidic equivalents of the proteins proved to be present at low levels in healthy plants. These results indicate that genes encoding basic and acidic isoforms of pathogenesis-related proteins are differentially regulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018553
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  • 7
    Electronic Resource
    Electronic Resource
    Octopine and nopaline strains of Agrobacterium tumefaciens differ in virulence; molecular characterization of the virF locus (1990)
    Springer
    Plant molecular biology 14 (1990), S. 249-259 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; virulence gene ; host range ; plant tumour induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Octopine and nopaline strains of Agrobacterium tumefaciens were found to differ in virulence on Nicotiana glauca. This difference is due to the absence of a functional virF locus, which is necessary for efficient tumorigenesis on N. glauca, from the nopaline Ti plasmids. Genetic studies and DNA sequence analysis of the virF locus revealed that virF embraces one open reading frame coding for a hydrophilic protein with a molecular mass of 22437 Da. Transcription of virF is directed from left to right, towards the T region, and is strongly induced by the phenolic compound acetosyringone. We established that virA and virG, two genes known to be essential for induction of the vir regulon, are necessary for acetosyringoneinduced virF expression, implying that virF is a member of this vir regulon. Agrobacterium virF mutants can be complemented for tumor induction by co-infection with avirulent Agrobacterium ‘helper’ strains. We found that such ‘helper’ strains must express not only the virF gene but also the vir operons virA, virB, virD and virG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018565
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  • 8
    Electronic Resource
    Electronic Resource
    Structure and expression of a light-inducible shoot-specific rice gene (1990)
    Springer
    Plant molecular biology 15 (1990), S. 399-406 
    Details
    ISSN: 1573-5028
    Keywords: light-inducible ; rice ; shoot-specific
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By differential screening of a cDNA library of two-week-old rice seedlings cDNA clones were obtained, corresponding to shoot-specific mRNAs. By sequence analysis two of these clones were found to be rbcS cDNA clones. The mRNA corresponding to a third cDNA clone (COS5) displayed an expression pattern similar to the expression pattern of rbcS genes. The mRNA (800 bases) was light-inducible and encoded by a single-copy gene. The genomic clone (GOS5) was isolated and the intron/exon structure was determined by comparing the nucleotide sequence of the mRNA and the genomic clone. The gene contains two introns. Transcription start sites were determined by S1-nuclease mapping and primer extension. The start site obtained by both methods is located 87 bp upstream of the translation start site and 23 bp downstream of TATA box-like sequence. In the 5′ non-coding region motifs can be found that are homologous to sequences in promoters that are light-or UV-inducible or confer leaf-specific expression. The open reading frame present in GOS5 codes for a protein (15 kDa) that contains a putative chloroplast transit peptide and does not show any significant homology to protein sequences in the NBRF protein database.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019157
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  • 9
    Electronic Resource
    Electronic Resource
    In planta analysis of the Agrobacterium tumefaciens T-cyt gene promoter: identification of an upstream region essential for promoter activity in leaf, stem and root cells of transgenic tobacco (1993)
    Springer
    Plant molecular biology 22 (1993), S. 923-929 
    Details
    ISSN: 1573-5028
    Keywords: A. tumefaciens ; T-cyt gene ; essential T-cyt promoter sequences ; gusA reporter gene ; T-cyt/gusA gene fusions ; transfected protoplasts ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The promoter region of the Agrobacterium tumefaciens T-cyt gene was fused to a β-glucuronidase (gusA) reporter gene and introduced into tobacco plants. Detection of gusA expression in transgenic F1 progeny revealed that the T-cyt promoter is active in many, if not all, cell types in leaves, stems and roots of fully developed plants. Developmental stage-dependent promoter activity was observed in seedlings. Analysis of 5′-deleted promoter fragments showed that sequences located between positions−185 and −139 with respect to the T-cyt translational start codon are essential for T-cyt promoter activity in transfected tobacco protoplasts as well as in transformed tobacco plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027379
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  • 10
    Electronic Resource
    Electronic Resource
    Apoptosis in barley aleurone during germination and its inhibition by abscisic acid (1996)
    Springer
    Plant molecular biology 32 (1996), S. 1125-1134 
    Details
    ISSN: 1573-5028
    Keywords: DNA fragmentation ; abscisic acid ; germination ; aleurone ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During germination of barley grains, DNA fragmentation was observed in the aleurone. The appearance of DNA fragmentation in the aleurone layer, observed by TUNEL staining in aleurone sections, started near the embryo and extended to the aleurone cells far from the embryo in a time dependent manner. The same spatial temporal activities of hydrolytic enzymes such as α-amylase were observed in aleurone. DNA fragmentation could also be seen in vitro under osmotic stress, in isolated aleurone. During aleurone protoplast isolation, a very enhanced and strong DNA fragmentation occurred which was not seen in protoplast preparations of tobacco leaves. ABA was found to inhibit DNA fragmentation occurring in barley aleurone under osmotic stress condition and during protoplast isolation, while the plant growth regulator gibberellic acid counteracted the effect of ABA. Addition of auxin or cytokinin had no significant effect on DNA fragmentation in these cells. To study the role of phosphorylation in ABA signal transduction leading to control of DNA fragmentation (apoptosis), the effects of the phosphatase inhibitor okadaic acid and of phenylarisine oxide on apoptosis were studied. We hypothesize that the regulation of DNA fragmentation in aleurone plays a very important role in spatial and temporal control of aleurone activities during germination. The possible signal transduction pathway of ABA leading to the regulation of DNA fragmentation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00041396
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