分离自棉花的轮枝菌“种”的鉴定

Identification of Isolates of Verticillium Species from Cotton

【目的】已知引起植物萎蔫病的轮枝菌有5个"种",本研究旨在澄清在中国引起棉花黄萎病的轮枝菌的"种"类。【方法】从中国12个省84个县分离获得310个轮枝菌菌株,采用生物学性状观察和分子鉴定相结合的方法,对其进行"种"的鉴定。【结果】298株均产生黑色微菌核和轮枝状分生孢子梗,为典型的大丽轮枝菌,另有12个菌株培养性状较为特殊(不产生微菌核,出现黑色菌丝或厚壁孢子),经温度敏感试验、PCR特异扩增及ITS序列进一步鉴定,2株被确定为变黑轮枝菌,其它10株被确定为大丽轮枝菌,没有出现黑白轮枝菌。【结论】在中国三大棉区,棉花黄萎病主要是由大丽轮枝菌引起的。但在长江流域和黄河流域棉区均分离到1株变黑轮枝菌,其在棉花黄萎病发生过程中的作用及其与大丽轮枝菌的互作还有待进一步研究。

【Objective】In the genus of Verticillium,there are five ＇species＇ as plant pathogens which could lead to plant wilt symptom.The aim of this study was to identify the specific ＇species＇ caused Verticillium wilt of cotton.【Method】A total of 310 Verticillium isolates were obtained from 84 counties,12 provinces of China.To clarify the ＇species＇ of them,both observation on biological characteristics and molecular identification were used.【Result】A total of 298 isolates were typical V.dahliae producing black microsclerotia and verticillate conidiophores identified by specific PCR amplifications.However,12 special isolates producing non-microsclerotia,black mycelia or chlamydospore were tested by temperature sensitivity,specific PCR amplification and ITS sequencing.Except for 2 V.nigrescens isolates,the rest 10 isolates were identified as V.dahliae,no V.albo-atrum was found.【Conclusion】 In 3 main cotton growing regions of China,the causal agent of cotton Verticillium wilt is V.dahliae.And V.nigrescens also presented in Yangzi River and Yellow River basins.In cotton Verticillium wilt happening process,the interaction between V.dahliae and V.nigrescens needs to be further studied.