猪繁殖与呼吸综合征病毒GX1003株全基因序列测定与分析

Genomic Sequence Analysis of Porcine Reproductive and Respiratory Syndrome Virus GX1003 Strain

为了解广西省猪繁殖与呼吸综合征病毒(PRRSV)的遗传变异情况,采用RT-PCR对PRRSV广西地方分离株GX1003株全基因组进行分段扩增、测序与分析。结果表明,不包括Poly(A)尾,GX1003株基因组全长为15 320nt。同源性分析表明,GX1003株与比对的国内外PRRSV美洲型毒株全基因核苷酸及其推导氨基酸序列的同源性分别为85.0%～99.4%和82.1%～99.1%,与欧洲型代表株LV株的同源性分别为60.6%和51.3%。序列分析表明,GX1003株的NSP2编码区存在第481位aa和第533～561aa发生30个氨基酸的不连续缺失,具有高致病性PRRSV(HP-PRRSV)的遗传特征;同时,在不同编码区出现与HP-PRRSV代表株JXA1株不同的遗传变异现象。遗传进化分析表明,比对的所有美洲型毒株可以分为4个亚群,GX1003株分布在以JXA1株为代表的亚群4中。表明PRRSV广西地方分离株GX1003株属于HP-PRRSV,但其基因组在不同区域发生了新的遗传变异。

To investigate the genetic variation of porcine reproductive and respiratory syndrome virus （PRRSV）, the full-length genome of PRRSV GXIO03 strain from Guangxi province were amplified by RT- PCR, sequenced and analyzed. The results showed that, excluding the poly （A） tail, the genomic se-uence of GX1003 strain was 15 320 nucleotides （nt） in length. Sequence analysis revealed that GX1003 strain shared 85.0%-99.4% nucleotide identity and 82.1%-99.1% amino acid identity with North American （NA） type isolates, and shared 60.6% nucleotide identity and 51.3% amino acid identity with European （EU） prototype LV strain. Sequence comparison demonstrated that GX1003 strain had discontinuous 30 aa deletion in 481 aa and 533-561 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 mul- tiple genomic variations in different regions. Phylogenetic analysis showed that all the NA type isolates could be divided into four subgroups, while GX1003 strain distributed in subgroup 4 represented by the highly pathogenic JXA1 strain. The results indicated that GX1003 strain from Guangxi province belonged to HP-PRRSV with new genetic variations in different regions.