Résumé
Between pathogen and host, antagonistic interactions impose strong reciprocal selection on each organism, leading to the development of arms race evolutionary dynamics. However, studies on specific recognition and co-evolution between resistance (R-) gene and avirulence (AVR-) gene are still limited. Here we show that AVRPik of Magnaporthe oryzae, the rice blast pathogen, and cognate rice R-gene Pik exhibit high levels of DNA polymorphisms causing amino acid changes. We found a tight recognition specificity of AVRPik alleles by different Pik alleles. Pik is composed of two kinds of CC-NBS-LRR, Pik1 and Pik2. We found that AVR-Pik physically interacts with the N-terminal coiled-coil domain of Pik1 in yeast 2-hybrid assay as well as in in-planta co-immunoprecipitation assay. Furthermore, this binding specificity corresponds to the recognition specificity between AVR-Pik and Pik alleles. These data suggest that the direct protein-protein interaction results in the arms race co-evolution between AVR-Pik and Pik. (Texte intégral)