猪繁殖与呼吸综合征病毒GX1001株和GX1002株全基因组分子特征分析

Analysis of Genomic Characteristics of Porcine Reproductive and Respiratory Syndrome Virus GX1001 and GX1002 Strains Isolated in Guangxi Province

为了解广西地区猪繁殖与呼吸综合征病毒(PRRSV)的变异情况及分子遗传特征,采用RT-PCR分段扩增2010年PRRSV广西地方分离株GX1001株和GX1002株基因片段,经克隆、测序、拼接,获得2个分离株的全基因序列。结果显示,不包括Poly(A)尾,GX1001株、GX1002株基因组全长分别为15329和15318bp。同源性分析结果表明,2个分离株间全基因组核苷酸序列同源性为99.3%,与国内外北美洲型代表毒株间的全基因组核苷酸序列同源性为84.9%～99.5%,与欧洲型代表毒株间的同源性为61.5%～61.9%。序列分析结果表明,2个分离株的NSP2编码区均存在第481和533-561位,共30个氨基酸的不连续缺失,具有PRRSV高致病性变异毒株(HP-PRRSV)的遗传特征,但分别在不同区域出现新的突变、缺失及插入等变异现象。遗传进化分析结果表明,所有美洲型毒株可分为4个亚群,GX1001株和GX1002株均属于以高致病性JXA1株为代表的第4亚群。上述结果表明,本研究获得的PRRSV广西地方分离株GX1001株和GX1002株均属于HP-PRRSV,但其基因组在不同区域发生了新的遗传变异现象。

To investigate the genomic characteristics of porcine reproductive and respiratory syndrome virus （PRRSV）, the full-length genome of PRRSV GX1001 and GX1002 strains from Guangxi province were amplified by RT-PCR, sequenced and analyzed. The sequence data showed that, excluding the poly （A） tail, the genomic sequences of GX1001 and GX1002 were 15329 and 15318 bp in length, respectively. Full-length sequence analysis revealed that GX1001 and GX1002 shared 99.3% nucleotide identity with each other, 84.9% to 99.5% nucleotide identity with representative North American （NA） type isolates, 61.5% to 61.9% nucleotide identity with representative European （EU） type isolates, respectively. Full-length sequence comparisons demonstrated that GX1001 and GX1002 had discontinuous 30 aa deletion in 481th aa and 533th to 561th aa of NSP2 region compared with that of the NA prototype VR-2332, which was considered as the genetic marker of highly pathogenic PRRSV（HP-PRRSV）, and had new multiple genomic variations such as mutation, deletion and insertion distributing in different regions. Phylogenetic analysis showed that all the NA type isolates could be divided into four subgroups, and GX1001 and GX1002 belonged to subgroup 4 represented by the highly pathogenic JXA1 strain. The results indicated that GX1001 and GX1002 strains from Guangxi province belonged to HP-PRRSV with new characteristic variations in different regions. This study provided valuable genomic data for further surveillance of HP-PRRSV.