豫西地区PRRSV新近流行株ORF5基因变异及Nsp2基因特征分析

为研究豫西地区猪繁殖与呼吸综合征病毒(PRRSV)新近流行株ORF5基因的变异情况及Nsp2基因的结构特征,采用RT-PCR方法扩增了26份近期采自豫西地区猪场疑似PRRS猪肺脏样品中的ORF5全序列和Nsp2部分序列,并对其生物信息学和结构进行了分析。结果表明:成功扩增出的21株PRRSV流行株间ORF5全基因同源性为96.6%～100%,氨基酸同源性为97.5%～100%;与参考毒株JXA1、MLV、VR-2332和LV的核苷酸同源性分别为96.6%～98.9%、88.4%～89.2%、88.0%～89.5%和66.8%～67.3%;对阳性病料进行了部分Nsp2基因的扩增,测序结果显示,所有流行株的Nsp 2基因与已报道的美洲株VR-2332相比,不存在核苷酸的插入或突变,但存在2个位点共90个碱基的缺失;遗传衍化分析表明,流行毒株属于美洲型。研究结果揭示了豫西地区新近流行的PRRSV ORF5基因的变异情况及Nsp 2基因的特征,为该地区的PRRS防控工作提供了理论依据。

Genetic Variations of the ORF5 and Nsp2 Genes of the Prevalent PRRSV Isolates from Western Henan Province

To determine the genetic variations of the ORF5 and Nsp 2 genes of prevalent PRRSV isolates from western Henan,the complete ORF 5 gene and subsequence for Nsp 2 gene of PRRSV were amplified by RT-PCR from lung samples of swine.A total of 21 complete ORF 5 and subsequence for Nsp 2 sequences were successfully amplified from 26 case samples.Homology for 21 complete ORF 5 gene and amino acids sequences are 96.5%-100% or 97.5%-100%,respectively.Compared to the reference strains JXA1,MLV,and VR-2332,the homology of gene were 96.5%-98.8%,87.4%-89.1%,and 87.7%-89.4%.Subsequence for Nsp2 sequence were amplified from positive samples and compared to other published sequences,two point deletions and 90 bp were deleted.It indicates that the prevalent PRRSV isolates from western Henan belong to Northern American genotype.Our study provides some basis for further controlling PRRS in this area.