河南省烟草黑胫病菌群体遗传结构的SSR分析

Genetic structure analysis of Phytophthora nicotianae population in Henan province by SSR marker

为明确河南省烟草黑胫病菌群体的遗传结构,本研究利用SSR分子标记对来自河南省12个地区的32株烟草黑胫病菌进行分析。结果显示,6对SSR引物共扩增出24个条带,其中多态性条带23个,多态性条带比率为95.83%;Nei’s基因多样性指数和Shannon信息指数分别为0.2132和0.3356;遗传相似系数在0.61~1.00之间,相似系数0.80水平下UPGMA聚类可将32个菌株划分为5个类群,其中类群I和类群II包括29个菌株,为优势类群;主成分分析结果与UPGMA聚类分析结果基本一致;遗传结构分析推测河南省烟草黑胫病菌群体来自于3个祖先亚群,亚群I、亚群II和亚群III在群体中所占比例分别为13.59%、46.61和39.80%;单个菌株遗传构成分析显示87.50%菌株的遗传组分几乎由单一亚群组成。以上研究结果表明河南省烟草黑胫病菌群体的遗传多样性水平较低,遗传结构也较为简单。

In order to identify genetic structure of P.nicotianae population in Henan province,32 P.nicotianae isolates from 12 areas in Henan province were studied by Simple Sequence Repeat(SSR)marker.Results showed that 24 bands were amplified by using 6 pairs of primers and 23 of them were polymorphic.The proportion of polymorphic bands was 95.83%.Nei's gene diversity and Shannon's Information index were 0.2132 and 0.3356,respectively.The genetic similarity coeffi cient of 32 isolates varied from 0.61 to 1.00.The UPGMA dendrogram of 32 isolates illustrated that they can be divided clearly into 5 groups at 0.80 level of genetic similarity.Result of principle coordinate analysis was similar to that of UPGMA clustering analysis.Result of genetic structure analysis showed that P.nicotianae population in Henan originated from 3 ancestral subpopulations.Subpopulation I,subpopulation II and subpopulation III accounted for 13.59%,46.61%and 39.80%,respectively.Genetic component of 87.50%of isolates almost consisted of only one subpopulation.These results indicated that the level of genetic diversity of P.nicotianae population from Henan was low and its genetic structure was simple.