抗稻瘟病基因PiK及其无毒基因AvrPik研究新进展

华南农业大学潘庆华课题组以稻瘟病菌无毒基因AvrPik和水稻稻瘟病抗病基因Pik为研究对象，首次阐明了寄主植物的抗病基因与病原菌的无毒基因之间存在的阶梯性“军备竞赛”的分子机制。相关成果日前在线发表于Molecular Plant-Microbe Interactions, MPMI上。

Stepwise Arms Race between AvrPik and Pik Alleles in the Rice Blast Pathosystem

摘要

A stepwise mutation occurred in both pathogens and their respective hosts has played seminal role in the co-evolutionary arms race evolution in diverse pathosystems. The process driven by rice blast AvrPik and Pik alleles was investigated through population genetic and evolutionary approaches. The genetic diversity of the non-signal domain of AvrPik was higher than that in its signal peptide domain. Positive selection for particular AvrPik alleles in the Northeastern region ofChinawas stronger than in the South. The perfect relationship between the functional lineages and AvrPik allele specific pathotypes was established by ruling out the non-functional lineages derived from additional copies. Only four alleles conditioning stepwise pathotypes were detected in natural populations, which were likely created by only one evolutionary pathway with three recognizable mutation steps. Two non-stepwise pathotypes were determined by two blocks in a network constructed by all the 16 possible alleles, indicating that a natural evolution process can be artificially changed by a combination of specific SNPs. Assuming that AvrPik evolution has been largely driven by host selection, the co-evolutionary stepwise relationships between AvrPik and Pik was established. The experimental validation of stepwise mutation is required for the development of sustainable management strategies against plant disease.