Les Phénolamides des Rachis de Palmes, Composants de la Réaction de Défense du Palmier Dattier vis‐à‐vis de Fusarium oxysporum f.sp. albedinis , Agent Causal du Bayoud

Phenolamides in the Rachis of Palms: Components of the Defence Reaction of the Date‐palm towards Fusarium oxysporum f.sp. albedinis , the Causal agent of ‘Bayoud’ This is the first study showing evidence of the production of phenolic and phenolamidic compounds in date palm tissues in response to attack by Fusarium oxysporum f.sp. albedinis (Foa), the causal agent of the wilt called bayoud. Marked quantitative and qualitative differences were recorded in the production of such compounds when infected and healthy rachis, were compared. In addition, localized accumulation of some compounds was detected when infected and healthy parts of the same rachis were analysed. Three induced hydroxycinnamoylamides were detected in high concentrations. They were isolated and tested for their toxicity against Foa. These compounds were shown to strongly inhibit conidial germination and germ tube growth of the pathogen and must be considered as phytoalexins. The role of amides in the date palm resistance to the bayoud is discussed.