瑞昌山药根腐线虫病病原鉴定

Identification of Nematode Causing Yam Root Rot in Ruichang City,Jiangxi Province

为给江西省瑞昌市山药根腐线虫病发生规律研究和有效防治提供理论依据,采用形态学和分子生物学技术对其病原线虫种类进行鉴定。从瑞昌市范镇、高丰、桂林3个乡镇的山药根腐线虫病样中分离获得15个寄生线虫分离物,镜检表明其形态特征和各项测量值符合对咖啡短体线虫的描述;提取线虫基因组DNA,利用通用引物对（X1/C1）对其核糖体DNA内转录间隔区（r DNA-ITS）序列进行PCR扩增,对扩增产物进行克隆、序列测定和序列分析,结果表明这10个分离物与咖啡短体线虫均具有最高的序列同源性（93%～99%）,并且在构建的系统发育树上与咖啡短体线虫共处于一个分支上。根据形态学和分子生物学鉴定结果,认为瑞昌山药根腐线虫病病原为咖啡短体线虫（Pratylenchus coffeae）。

In order to lay foundation for the study of occurrence law and effective control of yam root rot in Ruichang City,Jiangxi Province,the nematode species causing the disease were morphologically and molecularly identified.10 isolates of parasitic nematode were obtained from the yam root rot samples collected from three towns of Fanzhen,Gaofeng and Guilin in Ruichang city.The result of microscopic examination showed that the morphological characteristics and various measured values of these isolates had the most similarities with Pratylenchus coffeae.The genomic DNA of the nematode was extracted,and the r DNA-ITS sequence was amplified using universal primer pair（ X1 / C1） by PCR. Then the PCR products were cloned,sequenced,and the sequences were analyzed.The results showed that these ten isolates shared the highest sequence homology（ 93%-99%） with P. coffeae,and they were grouped into the same branch with P. coffeae in the phylogenetic tree.Based on the results of morphological and molecular identification,it is coucluded that P. coffeae is the pathogen of yam root rot in Ruichang city.