新疆主要棉区棉花黄萎病菌致病力分化及其遗传多样性分析

测定了源于新疆棉区的22个棉花黄萎病菌单孢菌株和3个落叶型棉黄萎病菌菌株T9、VD8和V151对4个棉花品种上的致病力.采用随机引物聚合酶链反应(RAPD)技术分析了这些菌株的遗传多样性.结果表明:供试的25个棉花黄萎病菌之间的致病力存在显著差异(P<0.05).在各棉花品种上,22个新疆菌株中都有与T9、VD8或V151的致病力差异不显著的菌株,说明新疆存在较强致病力的棉花黄萎病菌菌系.RAPD分析表明,供试的8个随机引物中6个可以从25个菌株的基因组DNA中稳定地扩增出多态性DNA片段.对扩增片段统计结果表明,供试菌株间遗传相似系数变化幅度为0.57～1.00.聚类分析表明,在阈值0.625处可将25个菌株分为4个RAPD群(命名为RG1、RG2、RG3和RG4),RG1包括2个菌株,即B、BL-19菌株; RG2 包括5个菌株,即BL-17、BL-13、N-5、H、N-16;RG3为最大一个亚群,包括T9、SL等16个菌株;RG4包括2个菌株,即VD8和V151.综合分析表明新疆棉花黄萎病菌的致病力强弱和菌株的采集地等遗传背景存在一定的差异,这可能与各主产棉区的频繁引种有着直接的联系.

Analysis on Pathogenicity Differentiation of Cotton Verticillium Dahliae Strains and Its Genetic Diversity in Xinjiang

In this study twenty-two Verticillium dahliae strains isolated from major cotton growth area in Xinjiang,comparing with the known defoliating type strain T9,VD8 and V151,were used to test pathogenicity differentiation on four cotton varieties,and to disclose the genetic diversity using random amplified polymorphic DNA(RAPD) assays.Significant pathogenicity difference(P<0.05) between these twenty-five strains was tested in our research.On each cotton variety,some of twenty-two Verticillium dahliae isolates from Xinjiang showing no difference in pathogenicity comparing with T9,VD8 or V151 were also observed.This result shows that there exists some strains having stronger pathogenicity in Xinjiang.The results of the pathogenicity tests also showed that the variety Zhongmian 35 was more tolerant than the other three cotton varieties to V.dahliae.RAPD assays showed that 6 out of 8 random primers could amplify the template DNA(genomic) extracted from the 25 isolates of V.dahliae.The similarity coefficient between the isolates calculated on the basis of the amplified DNA fragments was 0.57～1.00.Cluster analysis revealed that four RAPD groups(4 RGs : named RG1,RG2,RG3 and RG4) could be classified at 0.625(threshold line),RG1(including B and BL-19),RG2