甘肃定西地区甘蓝枯萎病病原菌的分离与鉴定

自2009年起,甘肃定西地区出现了甘蓝植株矮化、叶片黄化、枯萎甚至死亡的现象。2015年8月,我们采集了田间病株样本,使用常规组织分离法对病原菌进行了分离和纯化,依据柯赫氏法则进行了病原菌确认,并通过形态学和分子生物学方法对病原菌进行了鉴定。结果表明病原菌的形态学特征与尖孢镰刀菌Fusarium oxysporum一致,其rDNA-ITS、rDNA-IGS以及EF-1α序列与尖孢镰刀菌F.oxysporum相似性达99%,基于病原菌及尖孢镰刀菌各代表专化型EF-1α序列构建的系统发育树将该菌与尖孢镰刀菌黏团专化型F.oxysporum f.sp.conglutinans聚为一类,故引致甘肃定西地区甘蓝枯萎病的病原菌为尖孢镰刀菌黏团专化型F.oxysporum f.sp.conglutinans。

Isolation and identification of the pathogen causing cabbage wilt in Dingxi District, Gansu Province

Symptoms of stunting,leaf yellowing,withered and dead of cabbage were observed in Dingxi District,Gansu Province since 2009.Samples were collected from diseased field in August,2015.The pathogen was isolated and purified by the method of general tissue isolation,confirmed according to Koch's postulates,and identified by morphologic characteristics and molecular identification.The results showed that morphologic characteristics of the pathogen were consistent with those of Fusarium oxysporum.The similarity of rDNA-ITS,rDNA-IGS and EF-1α between F.oxysporum and the pathogen is 99％.The phylogenetic analysis of EF-1α gene sequences of F.oxysporum formae speciales and the pathogen showed that the pathogen was classified as F.oxysporum f.sp.conglutinans.Thus,the pathogen of cabbage wilt in Dingxi,Gansu was F.oxysporum f.sp.conglutinans.