东北地区水稻纹枯病菌遗传多样性和致病性分析

Genetic Diversity and Pathogenicity of Rhizoctonia solani Isolates Causing Sheath Blight Disease of Rice in Northeast Region

为明确东北地区水稻纹枯病菌遗传多样性与致病性之间的对应关系,为水稻抗病育种和水稻纹枯病的综合防治提供依据。对2015年采自东北地区水稻主产区的132株水稻纹枯病菌菌株进行了致病力测定和SRAP分析,其中112株为多核菌株(Rhizoctonia solani),20株为双核菌株(Rhizoctonia oryzae)。SRAP聚类分析结果表明:东北地区112株水稻纹枯病菌多核菌株的遗传相似性系数在0.52~0.97之间,在78%遗传相似水平下,划分为15个聚类组群;20株水稻纹枯病菌双核菌株的遗传相似性系数在0.65~0.90之间,在80%遗传相似水平下,划分为7个聚类组群,群体遗传多样性较为丰富,遗传结构与地理来源无明显相关性。选用辽星1号水稻品种对所有菌株进行致病性测定,结果表明:77.27%的菌株具有强致病性,8.33%的菌株具有中等致病性,14.39%的菌株具有弱致病性,东北地区水稻纹枯病菌致病力分化较为明显。对比聚类分析和致病性测定结果可知,SRAP类群划分与菌株的致病力鉴定之间不存在简单的对应关系。

In order to provide a basis for the comprehensive control of rice resistance to rice sheath blight, the relationship between genetic diversity and pathogenicity of R. solani in northeast region was established. In this study, 132 isolates of rice sheath blight were collected from the major rice producing areas in northeast of China. The pathogenicity and SRAP analysis were carried out among 112 multinucleate isolates（R. solani） and 20 binucleate isolates（R. oryzae）. The results of SRAP cluster analysis showed that the genetic similarity coefficient of 112 multinucleate isolates of R. solani were 0.52-0.97, and were clustered into 15 clusters at the 78% genetic similarity level; the genetic similarity coefficient of 20 binucleate isolates of R.oryzae were 0.65-0.90, and were clustered into 7 clusters under 80% genetic similarity. There was no significant correlation between genetic structure and geographical origin. Rice variety Liaoxing 1 was used to determine the pathogenicity of all isolates and the results showed that 77.27% of the isolates were highly pathogenic, 8.33% moderate pathogenic, 14.39% weakly pathogenic, indicating that the pathogenicity differentiation of R. solani was more obvious in the northeast. The result of cluster analysis and pathogenicity test showed that there was no simple correspondence between SRAP groups and pathogenicity identification.