PRRSV山东变异缺失株SX-1的全基因序列分子特征分析

Molecular characteristics of complete genome of a Shandong mutant strain of porcine reproductive and respiratory syndrome virus SX-1

对从山东某发病猪场采集的猪繁殖与呼吸综合征疑似病料中分离到的PRRSV病毒(SX-1株),应用RTPCR方法分段扩增出PRRSV SX-1毒株的各基因片段,扩增后的产物分别克隆于pMD-18T载体鉴定后测序。序列号GQ875656。序列分析结果表明SX-1株基因组全长15 320nt(不包括poly尾),包含9个开放阅读框,5′UTR长189 nt,3′UTR长150 nt;SX-1株在分子遗传演化上属于PRRSV变异毒株,与参考毒株JXA1的核苷酸同源性为98.9%;与CH-1a和VR2332的同源性为94.8%和89.5%;而与LV的同源性仅为59.3%。基因系统发育树分析结果显示,SX-1与JXA1、GDBY1株的亲缘关系很近,与CH-1a亲缘关系较近,与VR2332、CC-1、RespPRRS/Repro MLV等毒株处于不同的分支。

A strain of porcine reproductive and respiratory syndrome virus（PRRSV）was isolated from a pig herd with high fever syndrome in Shandong and it was designated as SX-1 strain.Gene fragments of SX-1 were amplified by RT-PCR and cloned into pMD18-T vector for sequencing.The results showed that the complete genome of SX-1 strain was 15 320 nt（excluding PolyA tail） containing nine open reading frames（ORFs） with 189 nt in the 5＇UTR and 150 nt in the 3＇UTR.The genome of PRRSV SX-lstrain shared 98.9%,94.8%,and 89.5%of nucleotide homology with JXAI,CH-la and VR2332,respectively.The phylogenetic tree revealed SX-1 had closer relationship with JXA1 and GDBY1 strains than that of CH-1a strain.