496 research outputs found
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
Etude du mode de colonisation des graines et des siliques de la plante modèle Arabidospis thaliana par Alternaria brassicicola, champignon pathogène des plantes de la famille des Brassicacées
Signaling pathways activated after exposure to phytoalexins: an Achilles'heel for necrotrophic fungi?
Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids
Flavonoids, like other metabolites synthesized via the phenylpropanoid pathway, possess a wide range of biological activities including functions in plant development and its interaction with the environment. Dihydrochalcones (mainly phloridzin, sieboldin, trilobatin, phloretin) represent the major flavonoid subgroup in apple green tissues. Although this class of phenolic compounds is found in very large amounts in some tissues (≈200 mg/g of leaf DW), their physiological significance remains unclear. In the present study, we highlight their tissue-specific localization in young growing shoots suggesting a specific role in important physiological processes, most notably in response to biotic stress. Indeed, dihydrochalcones could constitute a basal defense, in particular phloretin which exhibits a strong broad-range bactericidal and fungicidal activity. Our results also indicate that sieboldin forms complexes with iron with strong affinity, reinforcing its antioxidant properties and conferring to this dihydrochalcone a potential for iron seclusion and/or storage. The importance of localization and biochemical properties of dihydrochalcones are discussed in view of the apple tree defense strategy against both biotic and abiotic stresses
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