同一猪场的2株基因重组猪繁殖与呼吸综合征病毒的遗传演化分析

Genetic Evolution Analysis of Two Recombinant Porcine Reproductive and Respiratory Syndrome Virus from the Same Pig Farm in China

为分析本实验室2017—2018年从同一规模化猪场临床病料中分离的2株猪繁殖与呼吸综合征病毒(PRRSV)的分子遗传特征,本试验采用PCR方法对分离毒株的全基因组进行扩增,并使用分子生物学软件Simplot 3.5.1和RDP 4.24对其进行遗传演化和重组分析。结果显示,分离毒株FJDJQ-2017和FJDJQ-2018基因组全长均为15016 bp(去除polyA后),2个毒株之间的核苷酸相似性仅为85.8%,与代表性毒株NADC30、QYYZ、VR2332和JXA1的核苷酸同源性分别为92.7%/89.4%、82.8%/84.4%、84.9%/84.7%和83.2%/84.5%;Nsp2氨基酸序列分析显示,2个毒株均存在类NADC30毒株特征性的(111+1+19)aa的不连续缺失;基于全基因组遗传演化分析表明,2个毒株均属于谱系1,而基于ORF 5基因的进化树分析表明FJDJQ-2017属于谱系3,而FJDJQ-2018属于谱系1;重组分析结果显示,FJDJQ-2017株是以类NADC30毒株为主要亲本毒株,以类QYYZ毒株和类VR2332毒株为次要亲本毒株的重组毒株,而FJDJQ-2018株是以类NADC30毒株为主要亲本毒株,以类QYYZ毒株和类JXA1毒株为次要亲本毒株的重组毒株。本试验结果丰富了PRRSV重组毒株的基因信息数据库,也为预防和控制猪繁殖与呼吸综合征提供了参考。

To determine the molecular genetic characteristics of two porcine reproductive and respiratory syndrome virus(PRRSV)strains isolated from the same large-scale pig farm during 2017 to 2018,whole-genomes were sequenced of two isolated strains,and further genetic evolution and recombination were analyzed by biological software Simplot 3.5.1 and RDP 4.24.The results showed that the two isolates FJDJQ-2017 and FJDJQ-2018 were both 15016 bp in length,excluding the polyA tail,and had only 85.8%nucleotide similarity.Genomic sequence alignments revealed that the two isolates shared 92.7%/89.4%,82.8%/84.4%,84.9%/84.7%and 83.2%/84.5%homology with NADC30,QYYZ,VR2332 and JXA1,respectively.The Nsp2 amino acid sequence analysis showed that the two isolates displayed(111+1+19)aa discontinuous deletions pattern as NADC30.Phylogenetic tree analysis showed that the FJDJQ-2017 and FJDJQ-2018 clustered with lineage 1 on the basis of the full-length genome,however,FJDJQ-2017 belongs to lineage 3 and FJDJQ-2018 belongs to lineage 1 based on ORF 5 gene.The results of the recombination analysis showed that the FJDJQ-2017 strain recombined from NADC30-like strain(main parent strain),QYYZ-like strain(secondary parent strain)and VR2332-like strain(secondary parent strain),while FJDJQ-2018 strain recombined from NADC30-like strain(main parent strain),QYYZ-like strain(secondary parent strain)and JXA1-like strain(secondary parent strain).Thus,this study enriched the database of PRRSV recombinant information,and also provided references for the prevention and control of the disease.