利用ISSR技术分析禾谷镰孢菌群体遗传多样性的研究

采用ISSR标记对采自我国11个省的玉米茎腐病相关禾谷镰孢的遗传多样性进行分析。利用筛选出的14个ISSR引物对供试的115株禾谷镰孢菌株进行扩增,共获得63条扩增清晰、重复性高的条带,其中多态性条带为60条,占95.2%。扩增条带分子量为150～2000bp,平均每个引物扩增出4.5条带。遗传多样性分析表明,在地理种群水平上,基因多样性指数在0～0.2919之间,平均为0.1591;Shannon‘s多样性指数在0～0.4252之间,平均为0.2360,表明不同地理种群间存在一定的遗传变异。多样性指数、等位基因数的增大与各种群内样本数量增加有关。遗传相似性分析证明,山东省种群与河南省种群间的遗传相似性最高,内蒙古种群与河北省种群间遗传相似性最低。在相似性系数为0.682时,可将115个菌株区分为2个聚类组,各组下又可分为3个亚组,分组结果与菌株的地理来源有一定相关性,表明禾谷镰孢的遗传分化与生态地理有关。

Study on Genetic Diversity of Fusarium graminearum Populations Causing Maize Stalk Rot by ISSR Analysis

The genetic diversity of F. graminearum population collected from eleven provinces was determined using technique of inter-simple sequence repeat (ISSR). A total of 63 reproducible ISSR fragments were scored among 115 individuals, of which 60(95.2%) were polymorphic. The size of the amplified fragments ranged from 150 bp to 2 000 bp and average number of bands per primer was 4.5. At geographic population level, Nei's gene diversity and Shannon's information index were 0.159 1 and 0.236 0, respectively, that meant there was genetic variation between geographic population of F. graminearum. By analysis of genetic similarity coefficient the F.graminearum populations of Shandong and Henan were closest and populations of Inner Mongolia and Hebei were the farthest. Based on genetic distances all isolates were clustered into two groups at the similarity of 0.682 and three subgroups in each group. The grouping results indicated that genetic variation of F.graminearum was related with its geographic distribution.