一株猪蓝耳病毒的分离鉴定及其全基因组序列的比较分析

Isolation and identification of porcine reproductive and respiratory syndrome virus and genomic comparative analysis of the virus

关键词:  猪蓝耳病毒  分离  鉴定  全基因组  进化树

Key words:  PRRSV  isolation  identification  complete genome  phylogenetic analysis

摘要:

从湖北省某猪场分离了一株猪蓝耳病毒(CH-WH-19)，其基因组全长是14993 bp。同源性分析结果显示CH-WH-19与NADC30、JXA1、CH-1a、VR-2332和GM2的相似性分别为91.9%、84.3%、83.9%、83.3%和80.5%，但是与欧洲型的毒株Lelystad virus相似性仅有58.9%。GP5基因和全基因组的进化树分析显示，CH-WH-19与NADC30毒株处于同一分支。Nsp2基因氨基酸比对结果发现，CH-WH-19和NADC30毒株与VR2332毒株相比具有不连续的131个氨基酸缺失的特征。同源性和进化树的结果都显示了CH-WH-19属于新变异的类NADC30毒株。GP5序列比对结果表明，CH-WH-19有一些氨基酸的突变，A137是疫苗株VR2332的标志，但CH-WH-19毒株突变成了S，N34是四个潜在的N-糖基化位点之一，突变成了D。试验表明，本研究分离了一株变异的NADC30毒株，生物学特性分析也表明属于类NADC30毒株。

Abstract:

A new virulent strain of PRRS virus (PRRSV), CH-WH-19, was isolated in Hubei province, China. The genome of this new strain was 14993 nucleotides (nt) long, and comparative analysis revealed that CH-WH-19 exhibited 91.9%、84.3%、83.9%、83.3% and 80.5% nucleotide similarity to NADC30、JXA1、CH-1a、VR-2332 and GM2, respectively, but only 58.9% identity with type 1 PRRSV Lelystad virus strain. Phylogenetic analysis of the GP5 and genome indicated that CH-WH-19 and NADC30 strains were in the same branch, in which CH-WH-19 had the unique discontinuous 131-amino acid deletion relative to that of the nonstructural protein 2 (Nsp2) of the VR2332 strain. Both homology and evolutionary tree results showed that CH-WH-19 belonged to the newly mutated NADC30 strain. GP5 sequence alignment showed that CH-WH-19 had some amino acid mutations, and A137 was the marker of vaccine strain VR2332, but CH-WH-19 was mutated into S, one of the four potential N-glycation sites of N34, and mutated into D. In summary, a NADC30-like PRRSV was isolated in this study, and the biological characteristics analysis also revealed that it was NADC30-like PRRSV.