四川省不同寄主立枯丝核菌的遗传分化和致病力研究

Genetic diversity and pathogenicity variation of different Rhizoctonia solani isolates in Sichuan province

在四川省生态条件下,从不同水稻和玉米植株上分别分离到来源不同的立枯丝核致病菌15株和7株。致病力、菌 丝融合实验结果表明,菌株均属于AG-11A群,各菌株间致病力差异显著。对分离菌株进行RAPD分析,结果显示,相似系 数为0．92处菌株可聚合为5类,聚类分组和寄主来源有一定的相关性,来自相同寄主菌株的亲缘关系较近,不同寄主对立 枯丝核菌的遗传分化有一定的影响,与病原菌的致病力差异没有直接的相关性。

An analysis of hyphal fusion, pathogenicity variation and molecular genetic variation of 15 fungal isolates from different rice varieties and 7 isolates from maize in Sichuan province were presented. All the isolates were identified as Rhizoctonia solani AG-1IA and showed significant pathogenicity variation. The genetic variation of these isolates was assessed with RAPD （ random amplification of polymorphic DNA） method. In the dendrogram derived from RAPD data by UPGMA, the isolates could be classed into 5 subgroups at 0.92 similarity level. The isolates from the same host plant showed similar RAPD marker patterns and were clustered into the same genetic group or subgroup. These results suggest that a certain degree of genetic similarity exists among isolates recovered from the same host, whereas the pathogenicity variation was not related to host origin of isolates and RAPD groups.