禾谷丝核菌基因组SSR标记的开发及评价

Development and evaluation of genomic SSR markers in Rhizoctonia cerealis

群体遗传学研究对于了解病原菌的流行、变异及进化规律具有重要意义。但是到目前为止,对小麦纹枯病菌禾谷丝核菌群体遗传结构的了解并不深入,缺乏有效的SSR标记是主要原因。本研究根据禾谷丝核菌全基因组序列进行了微卫星位点搜索并设计SSR引物,通过电泳筛选和测序验证,最终筛选出12个多态性较好且稳定可靠的SSR标记。利用这些标记对收集自我国安徽、江苏、河南三省的23个禾谷丝核菌菌株进行了多态性分析,结果发现禾谷丝核菌基因组中长片段微卫星位点较少。12对引物扩增出的等位基因数平均为6.1个,期望杂合度平均为0.651,观测杂合度平均为0.508,表明这些标记具有较高的多态性,能够满足禾谷丝核菌群体遗传学研究需要。本研究为进一步进行禾谷丝核菌的多样性、群体遗传结构分析及进化学研究提供了有效工具。

It is important to understand the epidemiology, variation and evolution of pathogens by way of population genetics. Until now, we have known relatively little about the population genetics of Rhizoctonia cerealis, a pathogen causing wheat sharp eyespot for lack of available SSR markers. In this study, we analyzed the micro- satellite loci in the genome of R. cerealis and designed 481 SSR primers. Based on the electrophoresis results and sequencing confm-nation, 12 pairs of polymorphic SSR primers with stable amplification were selected to further evaluate the polymorphism among 23 R. cerealis isolates collected from Anhui, Jiangsu and Henan Provinces. The results showed that the long microsatellite loci were lacked in the genome of R. cerealis, and these markers were polymorphic with mean of allele numbers per locus, the expected and observed heterozygosity at 6.1, 0.651 and 0.508, respectively, which could be used in the population genetic study of R. cerealis. This study provides a useful tool to study the diversity, population genetic structure and evolution of R. cerealis.