不同年代大丽轮枝菌菌株的生物学特性和ISSR分析

 为了探究不同年代的大丽轮枝菌(Verticillium dahliae Kleb.)菌株生物学特性和遗传多样性方面的差异,本文以我国黄河流域和长江流域主产棉区6个省的不同年代大丽轮枝菌菌株为研究对象,观察培养性状,测定致病类型(致病力、落叶型),同时采用ISSR指纹图谱分析其遗传多样性。结果显示,不同年代大丽轮枝菌之间菌丝生长速率无显著差异,但菌核型菌株所占比例有减少趋势;2007~2009年和2017年的菌株全部为落叶型菌株,而1983~2000年的菌株中落叶型菌株仅占28.6%,表明随着年代的推移,黄河流域和长江流域的落叶型菌株所占比例呈上升趋势;不同年代菌株之间致病力存在显著差异,1983~2000年、2007~2009年和2017年的菌株中强致病力类型菌株分别占21.4%、25.0%和38.9%,仅有的5株弱致病力类型菌株均为1983~2000年的菌株;与2000年后的菌株相比,1983~2000年的菌株,Nei′s基因多样性指数为0.205 1,Shannon信息指数为0.299 0,表现出更丰富的多样性,利用NTSYS软件和Structure软件对ISSR指纹图谱进行聚类分析,两种方法均将所有供试菌株分为4个类群,且聚类结果与致病力和不同年代之间均具有一定的相关性,与地理来源无明显相关性。本研究结果表明,过去30年间我国黄河流域和长江流域棉田黄萎病菌落叶型和强致病力类型菌株所占比例逐渐升高,且不同年代和不同致病力的菌株在遗传上有差异,为进一步探究大丽轮枝菌的遗传与进化奠定了基础。

Biological characteristics and correlation with molecular marker in Verticillium dahliae from different years by ISSR analysis

The aim of this study was to compare the biological characteristics and genetic diversity in Verticillium dahliae isolates collected from different years. Forty-four V. dahliae isolates from six provinces in the main cotton-producing areas of the Yellow River Basin and the Yangtze River Basin during 1983-2017 were used to characterize the culture characteristics, pathogenicity and genetic diversity based on ISSR fingerprinting. The results showed that the isolates from 2007-2009 and 2017 were all defoliating type, while only 28.6% of the isolates from 1983~2000, suggesting that the proportion of defoliating type isolates is on the rise. The virulence of isolates from different years was significantly different. The strong virulence type of isolates from 1983-2000, 2007-2009 and 2017 accounted for 21.4%,25% and 38.9%, respectively; The only five isolates during 1983-2000 exhibited weak pathogenicity; the Nei′s gene diversity and the Shannons information index of isolates from 1983-2000 were 0.205 1 and 0.299 0, suggesting the isolates with higher genetic diversity level than isolates from the following years. In addition, ISSR fingerprints were clustered by NTSYS software and Structure software to divide all tested isolates into 4 groups, which were correlated with pathogenicity and different years, but not with geographical origin. The results of this study indicate that the proportion of defoliating type and strong virulence isolates of V. dahliae in the Yellow River Basin and the Yangtze River Basin kept increasing over the past 30 years, and the isolates from different years genetically varied in pathogenicity. Our findings may lay the basic foundation for further exploration of the inheritance and evolution in V. dahliae.