Role of mannitol in pathogenic determinism in Alternaria brassicicola

International audienc

Etudes des déterminants moléculaires impliqués dans la capacité de transmission d'Alternaria brassicicola aux semences d'Arabidopsis thaliana

Seed transmission is one on the most efficient way for fungal pathogens to survive and ensure their dispersal. On the other hand, contaminated seeds are compromised on their germination and survival capacities. Hence, we aimed at identifying molecular mechanisms involved in the transmission abilities of seed-borne fungi using the model pathosystem based on Alternaria brassicicola and Arabidopsis thaliana. We analyzed the response of A. brassicicola to various in vitro and in vivo conditions: stress induced by Brassicaceous defenses metabolites (camalexin, brassinin and isothiocyanates), stress related to a water deficiency (desiccation, sorbitol and PEG) and stress occurring during seed colonization through siliques. Concerning the first type of stress, we showed that indolic phytoalexins probably target mitochondria as revealed by altered respiration and mitochondrial membrane potential after short time exposures. Our analyses also revealed that the fungal response to water stress involved hydrophilins-like and eisosomal proteins. We showed that the expression of most of these proteins was dependent of at least one of the three protein kinases AbSch9, AbNik1 and AbHog1. Finally, our in planta analysis revealed an unexpected possible role of chromatin remodeling mechanisms in the regulation of fungal genes expression during seed transmission

Potentiating agents for protecting plants from fungal infections

This invention relates to a method for preventing, controlling or treating a fungal infection on a plant organ comprising applying to said plant organ a non-fungicidal amount or a potentiating amount of a composition comprising a potentiating agent of a plant defense molecule, in association with a phytopharmaceutical vehicl