稻瘟病菌无毒基因AVR-Pik一个新单倍型的功能鉴定

Functional Identification of the Novel Haplotype of Avirulence Gene AVR-Pik in Magnaporthe oryzae

稻瘟病菌无毒基因的变异会导致水稻抗病品种丧失抗性,因此,稻瘟病菌无毒基因变异机制的研究对于水稻抗病育种及抗病品种合理布局具有重要指导意义。为了更加全面地了解稻瘟病菌无毒基因AVR-Pik的变异机制,对课题组前期获得的来自全国各地100多株稻瘟病菌田间菌株中AVR-Pik位点的突变进行分析,发现了一个新单倍型AVR-PikG,其编码产物含有一个未见报道的点突变M58I。进一步的功能鉴定结果显示,表达Avr-PikG的稻瘟病菌菌株对所有供试Pik单基因系水稻均有毒,而表达Avr-PikD^(M58I)的菌株则对所有供试Pik单基因系水稻无毒,表明目前所有已知Pik等位基因的编码产物均无法识别新单倍型Avr-PikG,而Avr-PikG所含点突变M58I可能与其成功逃避抗病蛋白识别无关。

The variation of avirulence genes(AVR genes)in Magnaporthe oryzae always leads to the breakdown of resistance in disease-resistant rice cultivars.Therefore,the study on the variation mechanism of AVR genes in M.oryzae is of great guiding significance for the breeding and rational utilization of disease-resistant rice cultivars.In order to better understand the variation mechanism of AVR-Pik in M.oryzae,the variation of AVR-Pik locus in more than 100 field isolates of M.oryzae collected from all over the country was analyzed in this study,and a novel haplotype AVR-PikG was identified whose encoding product contains a previously unreported point mutation M58I.Further functional identification results showed that the strains expressing only Avr-PikG were virulent to all tested monogenic lines carrying different Pik alleles,while the strains expressing only Avr-PikD^(M58I) were all avirulent,which demonstrated that Avr-PikG could evade the recognition of all known resistance proteins encoded by different Pik alleles,but the point mutation M58I in Avr-PikG might not be associated with its successful immune evasion.