新疆、甘肃和河南部分地区甜瓜瓜类蚜传黄化病毒分子变异初步分析

从新疆鄯善县、甘肃瓜州县和河南通许县采集表现瓜类蚜传黄化病毒(Cucurbit aphid-borne yellows virus,CABYV)症状的甜瓜叶片样品63份,利用反转录PCR(RT-PCR)检测,从阳性样品中选取25个分离物扩增出1.4 kb的片段,并对其序列进行分析。结果表明:63份样品中,36份为CABYV阳性;获得的序列包括部分3′端的依赖RNA的RNA聚合酶(RdRp)基因、非编码区(NCR)和全长外壳蛋白(CP)基因。随机选取25个分离物的CP基因与GenBank中的序列进行比对,其序列相似性为93.2%~100%。通许分离物间序列相似性为98.8%~99.8%,瓜州分离物间序列相似性为98.2%~100%,鄯善分离物间序列相似性为99.2%~100%,组内表现出极高的同源性。基于其部分RdRp基因、NCR及CP基因序列构建的系统进化树表明:25个CABYV分离物与中国及周边地区(泰国、韩国等)的分离物聚为一簇,而与欧洲地区分离物距离较远,说明了该病毒分子变异与分离物的地理分布有关。

Preliminary Studies on Molecular Variation of Cucurbit aphid-borne yellows virus from Xinjiang,Gansu and Henan

Cucurbit aphid-borne yellows virus (CABYV) causes yellowing symptom in cucurbit crops and distributes widely in China.Sixty-three samples exhibiting yellowing symptom were collected from Shanshan ofXinjiang,Guazhou of Gansu,and Tongxu of Henan in China.Among them,36 were positive to CABYV detected by RT-PCR.A 1.4 kb fragment consisting of partial RNA-dependent RNA polymerase (RdRp),intergenic NCR and complete coat protein (CP)gene was amplified by RT-PCR from 25 positive samples.Blast analysis showed that the fragments have high similarities of 93.2％-100％ with other CABYV isolates from GenBank.The nucleotide sequence identities of CP gene were 99.2％-100％ for Shanshan isolates,98.2％-100％ for Guazhou isolates,98.8％-99.8％ for Tongxu isolates.Phylogenetic trees based on partial RdRp,NCR and CP genes showed that the 25 isolates had a very close relationship with other isolates from China and other countries neighboring China including Thailand,South Korea etc,but a distant relationship with European isolates,suggesting that CABYV variation appeared to be associated with its geographical distribution.