大白菜枯萎病病原镰刀菌种类的初步研究

Preliminary study on Fusarium species causing Chinese cabbage wilt

2014～2016年,由于栽培管理及重茬等原因,大白菜枯萎病在我国大面积发生,造成了巨大的经济损失。为了明确引起大白菜枯萎病的病原菌,本课题组从山东、内蒙古、河北、甘肃等大白菜主产区采集了具有典型枯萎病症状的病样,并对样品中的病原菌进行了分离和鉴定。形态学鉴定结果表明:分离物分别具有尖孢镰刀菌(Fusarium oxysporum)、茄病镰刀菌(F. solani)和木贼镰刀菌(F. equiseti)的形态学特征。柯赫氏法则验证结果表明:3种病原菌均能使大白菜发病,且发病症状与田间症状一致。此外,基于病原菌的r DNA-ITS和mt SSU序列的测序比对,3种病原菌与尖孢镰刀菌、茄病镰刀菌和木贼镰刀菌的同源性分别达99%～100%,这与形态学鉴定结果相一致。尖孢镰刀菌引起白菜枯萎病为国内首次报道,而茄病镰刀菌和木贼镰刀菌引起白菜枯萎病为国内外首次报道。

Due to improper cultivation management and continuous cropping, Fusarium wilt in cabbage has widely occurred in Chinese cabbage-producing regions, and ceused to serious economic losses in China during 2014-2016. To determine the pathogen of Chinese cabbage wilt, the plant samples exhibiting wilt symptom were collected from Shandong, Inner Mongolia, Hebei, and Gansu, etc. Then, the suspected pathogens were isolated and identified as Fusarium oxysporum, F. solani, and F. equiseti based on morphological characteristics. To sa- tisfy Koch＇ s postulates, the pure fungal cultures were inoculated on Chinese cabbage and the wilt symptoms were consistent with that in the field. Furthermore, the molecular evidences from the sequence aliments of rDNA-ITS and mt SSU with identity up to 99%-100% totally met the results of morphological characterization above. To our knowledge, this is the first report of Chinese cabbage wilt disease caused by F. oxysporum in China, and the new report of the disease by F. solani and F. equiseti in the world.