广东省水稻纹枯病菌遗传多样性与致病力分化的研究

Genetic Diversity and Virulence Variation of Rice Sheath Blight Strains (Rhizoctonia solani AG-1 IA) from Guangdong Province

摘要:

利用随机引物扩增多态性DNA（RAPD）分子标记技术分析了来自广东省7个县市48个水稻纹枯病菌菌株的遗传多样性。以筛选出的10个随机引物对菌株进行RAPD-PCR扩增,共产生了98个RAPD分子标记,其中89.9％的片段具有多态性。48菌株间的遗传相似性系数（以Nei基因一致度表示）在0.56-0.949之间,用UPGMA聚类分析可将它们分为5个RAPD遗传聚类群（A、B、C、D、E）,相同地区来源的菌株基本上聚类在同一组群内。在温室中对供试菌株进行致病性测定,结果表明所有菌株对水稻品种Tetep都有致病性,菌株间致病力差异显著（α=0.05）,病情指数范围为0.73-18.7,平均感病指数为5.24。试验分析结果表明水稻纹枯病菌具有丰富的遗传多样性,不同县市的菌株存在很大的遗传分化现象（FST=0.579）,RAPD遗传聚类组群的划分与菌株的地理来源有明显的相关性,但菌株的致病力差异与菌株的来源、遗传聚类组群的划分没有明显的相关性。

Abstract:

Forty-eight rice sheath blight strains (Rhizoctonia solani AG 1-IA) from seven counties in Guangdong province were analyzed for genetic diversity using RAPD technique. Ninety-eight RAPD bands were amplified with 10 arbitrary decamer primers, among which 89.9% were polymorphic. Analysis of amplified polymorphic DNA fragments showed that the Nei's similarity coefficients of isolates were 0.560 -0.949. The tested isolates could be classified into 5 RAPD groups (A, B, C, D, and E), and most of the isolates from the same area clustered in a same group by using UPGMA analyses. THe virulence test carried out in greenhouse showed that all isolates were virulent to rice variety Tetep, the disease index (DI) ranged from 0.73 to 18.7, the mean DI was 5.24, and the virulence variation was significant(α=0.05).The analysis showed that there existed abundant genetic diverdsity among rice sheath blight fungal popilations, and the genetic variation was very signficiant in R. solani AG 1- ⅠA population from different counties in Guangdong province (F_{ST=0.579). The RAPD clustering groups had obvious correlation with geographical origin, but the virulence variation had no significant correlation with geographical origin and with RAPD groups.}