猪繁殖与呼吸综合征病毒柳州地方株NSP2和ORF5基因变异分析

摘要

In order to offer the theoretical data for prevention and control of PRRS endemic in Liuzhou region,the partial NSP2 and ORF5 genes of PRRSV LZ5 and LZ6 strains were amplified by RT-PCR and sequenced.The obtained sequences were analyzed and compared with the published nucleotide sequences of other strains in GeneBank by DNAstar software.The results showed that the two strains were classified into the North American type of PRRSV.The partial NSP2 gene shared a common feature of two distinctive deletions in 483 and 535-563 amino acid, a 30 amino acids deletion in NSP2 were found. Sequence comparison of partial NSP2 and ORF5 gene revealed a sequence homology of 99.5% and 99.7% between them, with a similarity of 100% and 99.5% in deduced amino acid sequences respectively.Their NSP2 and ORF5 gene shared 94.7%-96. 2% and 97.2%-98.0% of nucleotide homology, and 92.0%-95.5% and 94.5%-97.0% of amino acid identity with the very viru- lent PRRSV strains which isolated in our country in recent years respectively.In conclusion, the PRRSV strains prevailed in the field of Liuzhou were highly homologous to the wave of PRRS occurred in 2006,with no new characteristics in gene sequence, and also with no distinct difference in geological origins.%为了给广西柳州预防和控制猪繁殖与呼吸综合症提供理论数据,本研究对利用RT-PCR方法扩增了该地区流行株LZ5和LZ6的NSP2和ORF5基因并进行测序分析,然后与GenBank中已发表的PRRSV毒株的NSP2和ORF5基因序列进行比较。结果显示,2株柳州地方流行株均属于美洲型,在NSP2基因第483位和535~563位氨基酸均存在30个氨基酸的不连续缺失,其NSP2和ORF5基因的核苷酸同源性分别为99.5%和99.7%,推导的氨基酸同源性分别为100%和99.5%;与近几年国内流行的高致病性蓝耳病代表性毒株之间的NSP2、ORF5基因核苷酸同源性分别为94.7%~96.2%和97.2%~98.0%,其推导的氨基酸同源性分别为92.0%~95.5%和94.5%~97.0%。序列分析结果表明此次柳州流行的PRRSV与2006年夏高热病引起的基因序列高度同源,在基因序列上并未显示出新的特性,在国内也缺乏明显的地域性差异。