Résumé
Scarce cases of disease durable resistance have been documented in plant/pathogensystems. Their thorough analysis may help to understand how durable resistance emerges and ismaintained and how it can be exploited in a sustainable manner. We analyzed the case of thedurable resistance of glutinous rice to blast disease caused by the fungus Magnaporthe oryzae in theYuanyang terraces (Yunnan, China). Multi-year sampling of fungal isolates on glutinous rice and non-glutinous rice indicated that two populations of the blast fungus co-exist and are only rarelyexchanged between these two rice hosts. Evaluation of the number of avirulence (Avr) effectors inthe two Magnaporthe oryzae sub-populations demonstrated that isolates from glutinous rice possessparticularly high numbers of Avr effectors. Moreover, agressivity of these isolates on glutinous riceand non- glutinous rice varieties was correlated with the Avr effector content. Experiments withisogenic M. oryzae strains pinpoint one Avr effector that seem to play a key role in the localadaptation of the two blast sub-populations.