sRNA analysis during Botrytis infection in tomato plants

The fungal pathogen botrytis is able to infect a wide range of plants. This fungus contains an arsenal of degradative enzymes that destroy the plant tissue as the infection progresses. This mechanism of infection is characteristic for necrotrophic pathogens. However Botrytis also possesses subtle specific tools to modulate plant defenses in its benefit. Two regions of the Botrytis genome act as factories producing high numbers of sRNA. These regions account for 45% of the total sRNA isolated from Botrytis during the infection of tomato plants. Several tomato genes were predicted to be targeted for silencing by these sRNA. Three different target prediction tools were used; Miranda, targetfinder and psRNAtarget. For the predicted targets the expression of the corresponding tomato gene was correlated with the expression of the corresponding sRNA pair. Only genes showing down-regulation during the early infection (early than 24hpi) were used for further analysis. GO enrichment analysis of target tomato genes revealed multiple enriched GO terms including, carbohydrate metabolism, post-translational protein modification and defense response. Using string database a network has been created where enrichment in signaling kinases was observed. This subnet of tomato kinases were divided in kinases related to defense and development. Key components of the tomato defense signaling pathway seems to be targeted by the sRNA produced by botrytis during the early stages of the infection.