利用ISSR分析栗疫病菌群体遗传多样性

本研究利用ISSR分子标记技术,对中国、日本、意大利及美国等四个栗疫病菌群体的遗传多样性和遗传分化进行了分析。自53个ISSR引物中筛选出11个引物，对以上四个群体的栗疫病菌11个子群体的220个菌株进行扩增,共检测到177个位点,其中多态位点为174个,多态位点百分率（P）为98.31%。11个栗疫病菌子群体的P平均值为20.43%；群体水平的Shannon信息指数（I）和Nei指数（h）分别为0.1769和0.7386；各个子群体I的平均值为0.0943，h的平均值为0.0614。比较表明，中、日、意、美栗疫病菌群体间具有较高的遗传多样性。栗疫病菌群体间的基因分化系数（Gst）为0.7386，其基因流（Nm）为0.1769，11个子群体间的遗传距离平均为0.2289。利用算术平均数的非加权成组配对法（UPGMA）对栗疫病菌11个子群体进行聚类,结果可分为3大类群。

Genetic Diversity of Cryphonectria parasitica Populations by ISSR Analysis

Genetic diversity and genetic differentiation of Cryphonectria parasitica，which were from China, Japan, Italy and the USA, were analyzed using inter simple sequence repeat (ISSR) molecular technique. Using 11 primers filtrated from total 53 primers, ISSR amplification was conducted in 220 individuals from eleven Cryphonectria parasitica subpopulations which were from four countries, and 174 polymorphic loci were detected from total 177 loci. The percentage of polymorphic loci (P) of the total populations was 98.31%, while that at a subpopulation level averaged 20.43 %. Shannon’s Information index (I) and Nei’s gene diversity (h) of the fungus at the total populations level was 0.1769 and 0.7386, respectively. The mean of I and h at a subpopulation level was 0.0943 and 0.0614, respectively. It indicated that the genetic diversity of C. parasitica between the populations was relatively high. The genetic differentiation coefficient (Gst) among populations was 0.7386. The gene flow (Nm) among populations was low down to 0.1769. The mean of pair-wise genetic distance between eleven C. parasitica subpopulations was 0.2289. These eleven subpopulations could be clustered into three groups using unweighted pair group method with arithmetic mean (UPGMA).