本文利用随机引物扩增多态性DNA (RAPD)技术分析了7个生物学性状差异较大核盘菌(Sclerotinia sclerotiorum)的遗传多样性,并同三叶草核盘菌(S.trifoliorum)、小核盘菌(S.minor)的代表性菌株和莴苣上的一种产菌核病原菌的代表菌株Let-19进行了比较。结果表明40个引物中8个引物能稳定地从供试菌株中扩增出多态性DNA片段。通过分析这些多态性片段可以看出7个供试核盘菌菌株之间的遗传相似系数变化幅度为0.505 2~0.793 1,而核盘菌、三叶草核盘菌,小核盘菌和Let-19之间的遗传相似系数的变幅则为0.194 2~0.385 3。莴苣上的菌株Let-19的RA PD图谱同供试其它种的菌株既存在明显差异的DNA片段电泳带,又显示出一些位置一致的DNA片段电泳带。因而Let-19同核盘菌属真菌的亲缘关系较近。供试的引物中OPL14既能介导从供试的7个核盘菌菌株和3个近缘种的3个菌株的DNA样品中扩增出相同的DNA片段,又能扩增出种或菌株特异性DNA片段。因而RAPD技术适于研究核盘菌的遗传多样性及分析核盘菌属真菌的亲缘关系。

Random amplified polymorphic DNA (RAPD) assay was used to distinguish strains of Sclerotinia sclerotiorum with different characteristics and its related species S.trifoliorum strain Ywd-A, S. minor strain 3-4-1 and unknown species strain Let-19. The results showed that 8 out of 40 primers (10-mer) could stably amplify the genomic DNA from the tested strains.Analyses of amplified polymorphic DNA fragments showed that similarity coefficients between the tested strains of S.sclerotiorum were 0.5052-0.7931,whereas those between 7 strains of S. sclerotiorum and 3 strains representing other two species of Sclerotinia and Let-19 were 0.1942-0.3853.In UPGMA phenogram, Let-19 is located between S.trifoliorum strain Ywd-A and S.minor strain 3-4-1 with regards to phylogenetic relationships with strains of S.sclerotiorum. Seven strains of S.sclerotiorum were classified into three groups, but the classifi-cation was not related to their biological characteristics. It is concluded from this research that RAPD assay can be used to evaluate genetic diversity of S. sclerotiorum and to disclose phylogenetic relationship in Sclerotinia species.