| 摘要: |
| 【目的】了解2007－2009年部分猪群中猪繁殖与呼吸综合征病毒(PRRSV)株的遗传演化规律。【方法】按常规方法，从2007－2009年收集的疑似蓝耳病猪群组织样品中分离PRRSV，应用RT-PCR方法，对分离的10株PRRSV的ORF5和Nsp2基因进行扩增，测序后与19个PRRSV参考毒株的ORF5、Nsp2基因进行核苷酸、氨基酸序列比较及遗传进化分析。【结果】分离到的SDWF5、SDCX1、LN3、LN8、LN12、SD2、SD5、SD14、ZB1、ZB2共10株PRRSV均属于美洲型PRRSV变异株，其ORF5基因全长均为603 bp，编码约200个氨基酸，其推导氨基酸序列变异主要发生在9～39位；SDWF5、SDCX1、LN3、LN12、SD2、SD5、SD14、ZB2等8个分离株的Nsp2基因全长为2 845 bp，编码950个氨基酸，与代表毒株VR-2332相比，8个分离株在Nsp2基因推导氨基酸序列的480和532～560位发生了不连续的30个氨基酸缺失。与19个PRRSV参考毒株的ORF5、Nsp2序列进行比较后发现，10个分离株的ORF5、Nsp2基因核苷酸序列及其推导氨基酸序列均发生了较大变异。遗传进化分析发现，10个分离株与以CH-1a为代表的国内流行毒株处于同一分支，与JXA1等变异毒株的遗传距离较近。【结论】来源于不同猪群的10个PRRSV分离株的遗传关系存在交叉，没有明显的地域特征，但可能具有相同的始祖Ch-1a。 |
| 关键词: 猪繁殖与呼吸综合征病毒变异株 ORF5基因 Nsp2基因 遗传变异 |
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| 基金项目:国家“十一五”科技支撑计划项目“重大动物疫病病原快速检测技术研究和开发”（2006BAD06A11） |
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| Cloning and sequence analysis of ORF5 and Nsp2 genes of porcine reproductive and respiratory syndrome virus from some pig farms in 2007-2009 |
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| Abstract: |
| 【Objective】The study was to understand the genetic evolution of porcine reproductive and respiratory syndrome virus (PRRSV) strains from different pig farms in 2007－2009.【Method】10 PRRSV isolates were isolated from 10 pig farms-suffered PRRS in 2007-2009,ORF5 and Nsp2 genes of these isolates were amplified,sequenced,compared and phylogenetic analysed with 19 reference PRRSV.【Result】SDWF5,SDCX1,LN3,LN8,LN12,SD2,SD5,SD14,ZB1,ZB2 10 are variant strains of North America PRRSV,of which ORF5 genes were composed of 603 nucleotides,encoded polypeptides of 200 amino acid residues,variations of the deduced amino acids of ORF5 gene mainly occurred at positions of 9 to 39.Nsp2 genes of 8 PRRSV isolates were composed of 2 845 nucleotides,encoded polypeptides of 950 amino acid residues.Relative to the representative strains VR-2332,there are two deletions of 30 amino acid in Nsp2 protein 480,532-560 aa of SDWF5,SDCX1,LN3,LN12,SD2,SD5,SD14,ZB2 PRRSV isolates.Compared with ORF5 and Nsp2 gene nucleotide and amino acid sequence of 19 reference PRRSV,10 isolates of ORF5 and Nsp2 genes and their deduced amino acid sequence have occurred in a larger variation.Phylogenetic analysis based on gene sequence of ORF5 and Nsp2 showed that all isolates sharing a close distance evolutionary relationship with CH-1a,and showed a closer distance evolutionary relationship with JXA1.【Conclusion】There is a cross cutting phenomenon on the genetic relationship of PRRSV-isolates which isolated from 10 different pig farms,and no obvious geographical characteristics.We can assumed that they have a common ancestor Ch-1a. |
| Key words: variant strain of porcine reproductive and respiratory syndrome virus ORF5 gene Nsp2 gene genetic variation |
