Modulation des réactions de défense du palmier à huile contre le Fusarium oxysporum f. sp. elaeidis (Schlecht) Toovey. Applications : prémunition et stimulation chimique

Defence reactions of palm trees to Fusarium oxysporum f. sp. elaeidis (Schlecht) Toovey Cross protection and stimulation of inhibitory substances In palm tree genetic characters of tolerance to Fusarium oxysporum f. sp. elaeidis are correlated with synthesis of fungal inhibitors in infected tissues. Individual variation of synthesis level is also observed among plants of a same line. Defence reactions are triggered by pre-inoculation of an avirulent strain of Fusarium oxysporum. Similar results are obtained by application of analogs of fungal elicitors like arachidonic acid. Quite the contrary, treatment of plants with a competitive inhibitor of PAL downs natural barriers and in a same way the effects of cross protection and arachidonic treatment. Seven phenolic compounds, mainly benzoic acid derivatives, inhibit in vitro the growth of pathogen like spores germination. The variability of the host reaction and its stimulation by elicitors could be used to improve the resistance.