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Complex regulation of gene expression, photosynthesis and sugar levels by pathogen infection in tomato
Author(s) -
Berger Susanne,
Papadopoulos Martina,
Schreiber Ulrich,
Kaiser Werner,
Roitsch Thomas
Publication year - 2004
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2004.00433.x
Subject(s) - biology , photosynthesis , pathogen , chlorophyll fluorescence , pseudomonas syringae , gene expression , microbiology and biotechnology , botany , gene , biochemistry
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.