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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Munksgaard International Publishers
    Physiologia plantarum 122 (2004), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The infection of plants with pathogens results in the induction of defence reactions as well as changes in carbohydrate metabolism. On the one hand, the pathogen attempts to manipulate the carbohydrate metabolism of the plant for its own advantage. On the other, the plant has to reorganize carbon fluxes to ensure fight against the pathogen. In order to further investigate the connection between pathogen infection and carbohydrate metabolism, the effects of two types of pathogen, biotrophic and necrotrophic, on gene expression, endogenous sugar levels and photosynthesis of tomato plants were analysed. Photosynthetic gene expression was downregulated on infection with Pseudomonas syringae and Botrytis cinerea. In contrast, expression of a sink-specific gene encoding a cell wall invertase and of defence genes was induced by both pathogens. These results provide evidence for a co-regulation of defence, sink and photosynthetic gene expression in planta in response to both types of pathogen. The brassinosteroid-containing plant restorative ComCat enhanced resistance against B. cinerea and counter-regulated the repression of photosynthetic gene expression. Endogenous sugar levels decreased and the hexose to sucrose ratio increased on treatment with B. cinerea. The application of chlorophyll fluorescence imaging revealed the spatio-temporal heterogeneity of the pathogen response. At 24 h after infection, inhibition of photosynthetic electron transport was restricted to the direct vicinity of the infection site, which was surrounded by a circle of increased photosynthetic activity. The photosynthesis of the remaining leaf was not affected at this stage. These results show the usefulness of chlorophyll fluorescence imaging for the assessment of the complex spatio-temporal changes and for the definition of the areas relevant for other types of determination, e.g. gene expression.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 114 (2002), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Vegetative storage proteins (VSPs) are thought to fulfil important nutritional roles during plant development and stress adaptation. Plant responses to mechanical wounding and herbivore damage include an activation of VSP expression. It was recently suggested that vsp is part of the systemic response of Arabidopsis to wounding. To test this proposal, we monitored the spatial regulation of vsp mRNAs and VSP proteins. Arabidopsis contains two vsp genes and real-time quantitative PCR allowed us to characterize their differential expression. The ratio of vsp1 to vsp2 mRNA abundance increased when plants were challenged with diamondback moth larvae or Egyptian cotton worms, but not when they were mechanically wounded. We observed a dramatic increase of vsp1 and vsp2 mRNA as well as VSP protein levels in leaves that experienced herbivore damage. By contrast, there was a relatively minor increase of vsp mRNA and VSP protein levels in undamaged leaves of infested plants. These results clearly demonstrate that VSPs are part of the local plant response to herbivore attack. To obtain additional information on vsp regulation, we analysed a fusion of a soybean vspB promoter fragment to the β-glucuronidase gene in transgenic Arabidopsis plants. The vspB promoter responded to both jasmonate and herbivore treatments, suggesting that similar signals regulate its expression in both plant species.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2048
    Keywords: NAD(P)H-plastoquinone-oxidoreductase ; ndhH gene ; Plastid DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The plastid genomes of higher plants contain eleven reading frames (ndhA-K) that are homologous to genes encoding subunits of the mitochondrial NADH-ubiquinone-oxidoreductase (complex I). The carboxyterminal end of the NDH-H subunit from rice (Oryza sativa L.) was expressed as a fusion protein in Escherichia coli and antibodies against the fusion protein were generated in rabbits. The antibody was used to study the expression of NDH-H, and the following results were obtained: (i) NDH-H is expressed in mono- and dicotyledonous plants, (ii) NDH-H is localized on the stroma lamellae of the thylakoid membrane and (iii) NDH-H is expressed in etioplasts. Together with the finding that two other ndh genes (ndhI and ndhK) are expressed in plastids, these results point to the existence of an NAD(P)H-plastoquinone-oxidoreductase on the thylakoid membrane. The possible function of the enzyme in plastids is discussed and it is suggested that it works in balancing the ATP/ADP and the NADPH/NADP ratios during changing external (i.e. light) or internal (i.e. ATP and NADPH demands of biosynthetic pathways of the plastid) conditions.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-5028
    Keywords: Arabidopsis ; jasmonic acid ; soybean ; vegetative storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The soybean vegetative storage proteins, VSPα and VSPβ, are acid phosphatases that accumulate to very high levels in hypocotyls, young leaves and flowers and pods. The genes encoding the soybean VSP are activated by jasmonate, wounding, sugars and light and down regulated by phosphate and auxin. In this study, expression of an Arabidopsis thaliana gene (Atvsp) encoding a protein homologous to soybean Vspα and Vspβ, was examined and compared to expression of the soybean Vsp genes. Atvsp mRNA was present at high levels in flowers and buds and at low levels in roots, stems, leaves and siliques. Expression of Atvsp in leaves could be induced by wounding or by treatment of illuminated plants with methyl jasmonate and sucrose. Roots of plants with wounded leaves also accumulated Atvsp mRNA indicating that this gene can be regulated by a transmissible wound signal. Phosphate partially inhibited expression of Atvsp. Arabidopsis proteins of 29 and 30 kDa crossreacted with antibodies against soybean VSP. These proteins were very abundant in flowers and the proteins accumulated in leaves and roots of plants treated with methyl jasmonate. The level of these proteins in flowers was similar to the levels of soybean VSP in young soybean leaves. Overall, these data indicate that Arabidopsis Atvsp and soybean VspA/B genes are regulated similarly and that in both plants, the gene products can accumulate to high levels. This suggests that genes homologous to VspA/B may be of greater general significance than previously recognized.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 71 (1999), S. 380-384 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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