华南瓜类疫霉的RAPD遗传多样性分析

RAPD genetic diversity analysis of Phytophthora melonis from South China

为了解来自广东和广西的瓜类疫霉的遗传多样性,利用从180条RAPD引物中所筛选出的多态扩增性强、重复性好的12条引物,对分离自两省区的96株瓜类疫霉进行了全基因组DNA遗传多样性分析和指纹图谱构建。通过对供试菌株的RAPD-PCR扩增,共获得135条DNA标记谱带,其中124条为多态性谱带,多态检测率为91.9%。利用NTSYSpc Version2.1软件对供试菌株间的遗传距离进行聚类分析并构建系统树,以遗传相似系数0.81为阈值,将96个供试菌株划分为12个RAPD群,多数分离物之间遗传相似性较低,在DNA水平上存在显著的遗传变异,具有较丰富的遗传多样性。不同地区间菌株的遗传分化程度不同,分离自黄瓜的菌株遗传分化明显高于分离自冬瓜的菌株。RAPD群与菌株地理来源、分离寄主、致病力、交配型及甲霜灵抗性均无明显的相关性。

The method of random amplified polymorphic DNA （RAPD） was used for population analysis of 96 strains of Phytoph-thora melonis sampled from Guangdong Province and Guangxi Autonomous Region. Among the 180 tested primers, 12 ones were found to produce consistent polymorphic bands, and they were applied for RAPD analysis. At last 135 RAPD marker bands were generated, of which 124 ones showed polymorphism, accounting for 91.9% of the total bands. Based on genetic distance, a dendrogram was constructed with the software NTSYSpc Version 2.1, and the 96 tested strains were divided into 12 RAPD groups at 0.81 genetic similarity coefficient. Among the majority of these strains, their genetic similarity coefficients were low, and their genetic variations were clearly evident. It is concluded that considerable genetic variation exists among the strains of P. melonis n South China. Its genetic differentiation varied with geographic locations. The strains isolated from cucumber plants showed more evident genetic variation than those isolated from wax and geographic origin, host, virulence, mating type, or metala go xyl urd plants. No correlation was found between the RAPD clades resistance