1株多谱系毒株重组猪繁殖与呼吸综合征病毒的分离鉴定和遗传变异分析

Isolation,identification and genetic variation analysis of a multi-lineage strain recombined porcine reproductive and respiratory syndrome virus

从发病猪肺脏组织中检出猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV),将毒株命名为GXGG202007。对该毒株进行了病毒的分离以及全基因组测序、遗传演化分析和重组分析。结果显示GXGG202007毒株全基因组为15517个核苷酸(nt);基于ORF5、nsp2和全基因组构建的系统发育树均显示该毒株处于谱系3分支;同源性分析表明其与QYYZ毒株的相似性最高(91.4%),与欧洲株Lelystad-virus(LV)相似性最低(60.3%);通过多种生物信息学软件的重组分析显示,该毒株存在4个重组事件,是1株以谱系3代表毒株QYYZ为骨架,谱系8毒株和谱系5毒株提供重组片段的多谱系重组毒株,其中与HP-PRRSV-like毒株和RespPRRS MLV-like毒株可能分别在42~2008,6884~8549,13061~13853,8550~9523 nt处发生了重组,重组断点位于基因组的nsp2、nsp9和ORF3中。

A pig lung tissue collected from a diseased pig was confirmed to be PRRSV positive by RT-PCR.The PRRSV strain was named GXGG202007.The virus isolation,whole genome sequencing,genetic evolution analysis and recombination analysis of GXGG202007 were carried out.The results showed that this strain could be isolated in Marc-145 cells.The whole genome of the GXGG202007 strain contains 15517 nucleotides.Phylogenetic trees based on nsp2,ORF5 and whole genome showed that this strain clustered into lineage 3.Nucleotide homology analysis showed that it shared the highest similarity with strain QYYZ(91.4%)and the lowest similarity with European strain Lelystad-virus(LV)(60.3%).Recombination analysis using RDP5 showed that GXGG202007 strain was a natural recombinant virus originated from lineage 3,lineage 8 and lineage 5 PRRSV.The genome backbone of GXGG202007 was provided by the representative strain QYYZ of lineage 3,and the recombinant fragments were provided by lineage 8(HP-PRRSV-like)and lineage 5(RespPRRS MLV-like).The recombination breakpoints of GXGG202007 were located at Nsp2(42-2008 nt),Nsp9(6884-8549 nt and 8550-9523 nt)and ORF3(13061-13853 nt)in the genome.This study provides reference for understanding the genetic variation and prevention and control measures of PRRSV in Guangxi Province.