瑞昌山药花叶型病毒病毒原的分子鉴定及其遗传变异性分析

Molecular Identification and Genetic Variation of Virus Causing Yam Mosaic Virus Disease in Ruichang City

为了明确瑞昌山药花叶型病毒病的毒原种类和遗传变异性大小,为该病研究和防治提供理论依据,根据前期研究结果,采用自行设计的日本山药花叶病毒(Japanese yam mosaic virus,JYMV)特异性引物,对从江西省瑞昌市白杨、范镇、高丰、洪下4个乡镇采集的20份呈典型花叶症状的病叶进行PCR检测,对扩增片段进行序列测定和同源性分析,结果发现每个样品中均存在JYMV,初步表明JYMV为瑞昌山药花叶型病毒病毒原。将瑞昌20个JYMV分离物CP基因序列相互进行同源性比较,发现其遗传变异性较大,核苷酸序列同源性为92.8%~100%,平均96.7%;氨基酸序列同源性为95.2%~100%,平均98.1%。基于CP基因序列,对来自江西瑞昌、中国广西和日本共32个JYMV分离物构建系统发育树,结果 32个分离物按其地域来源形成了3个独立的进化组群,且瑞昌分离物与广西分离物之间的亲缘关系近于瑞昌分离物与日本分离物之间的亲缘关系。显而易见,JYMV的进化与其地理来源具有明显的相关性。

In order to determine the pathogenic species and genetic variability of Ruichang yam mosaic virus disease,and provide a theoretical basis for the study and control of the disease,20 diseased leaf samples showing typical mosaic symptoms were collected from four towns of Baiyang,Fanzhen,Gaofeng and Hongxia in Ruichang City of Jiangxi Province.On the basis of previous studies of the authors,all samples were subjected to virus detection by PCR using specific primers of Japanese yam mosaic virus（ JYMV）,and the PCR products were directly sequenced and the sequence homology was analyzed. It was found that JYMV existed in each sample,which preliminarily indicated that JYMV is the pathogen of Ruichang yam mosaic virus disease. The homology of CP gene sequences of 20 JYMV isolates in Ruichang was compared.It showed obvious genetic variability among them with 96. 7% of average homology of the nucleotide sequence,ranging from 92. 8%-100%,and98.1% of the average homology of the amino acid sequence,ranged from 95.2%-100%.A phylogenetic tree of32 JYMV isolates from Ruichang,Guangxi autonomous region and Japan was constructed based on the CP gene sequence.As a result,32 isolates formed 3 independent evolutionary groups based on their geographical origin,and the genetic relationship between the isolates from Ruichang and those from Guangxi was closer than the genetic relationship between the isolates from Ruichang and those from Japan.It was concluded that JYMV isolate evolution was closely related to its geographical existence.