5株类NADC30猪繁殖与呼吸综合征病毒全基因组测序及分析

Genomic analysis of five NADC30-like porcine reproductive and respiratory syndrome viruses

为了解类NADC30猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的基因组变化情况与分子流行病学特征,对本实验室已鉴定为类NADC30阳性样品进行全基因组测序,共得到5个类NADC30 PRRSV全基因组,并依次命名为180049-1,180770-16,180546-27,180450-1,180253-5。对5株类NADC30毒株的NSP2蛋白进行氨基酸序列比对结果表明:与VR2332株对比,5株毒株在NSP2蛋白322~432,483,504~522位均存在111+1+19个氨基酸的不连续缺失,与已报道类NADC30毒株的缺失特征相同。其中,180546-27毒株在NSP2蛋白除具有与NADC30相同的氨基酸缺失以外,在毒株NSP2蛋白中位置18~23,805~806含有额外的6+2个氨基酸缺失。核苷酸同源性分析结果表明:180049-1,180770-16,180546-27,180450-1,180253-5全基因与CH-1a(谱系8)的核苷酸同源性分别为93.3%,84.8%,86.0%,83.9%和84.4%;与JXA1(谱系8)的同源性分别为96.6%,84.4%,86.3%,83.1%和84.0%;与NADC30(谱系1)的同源性分别为85.7%,93.4%,91.9%,93.7%和93.8%;与QYYZ(谱系3)的同源性分别为86.5%,82.4%,83.0%,81.6%和82.0%;与VR2332(谱系5)的同源性分别为89.0%,85.2%,85.3%,85.0%和85.3%。对ORF5基因和全基因组遗传演化分析表明:180049-1毒株属于谱系8,180770-16,180546-27,180450-1,180253-5毒株属于谱系1中的类NADC30亚群。重组结果表明,180450-1可能由NADC30与VR2332样毒株重组而来,而180049-1,180770-16,180546-27,180253-5可能由NADC30与HP-PRRSV样病毒重组而来。本试验结果为PRRSV流行株的重组、演化分析和防控提供借鉴意义。

To understand the genomic changes and molecular epidemiological characteristics of the NADC30-like porcine reproductive and respiratory syndrome virus whole-genome sequencing was performed in the NADC30-like-positive samples identified in our laboratory.A total of five NADC30-like genes were obtained and named as 18049-1,180770-16,180546-27,180450-1,and 180253-5,respectively.Amino acid sequence alignment of the NSP2 proteins of five NADC30-like strains indicated that 5 strains had discontinuous deletions of 111+1+19 amino acids in the NSP2 protein at positions 322-432,483,and 504-522 compared with VR2332,which were identical to those of the reported NADC30 strain.Among them,the strain 180546-27,in addition to the same amino acid deletion as NADC30,6+2 amino acid was deleted at position 18-23,805-806 in NSP2 protein.The nucleotide homology of the 5 strains with CH-1 a(lineage 8)was 93.3%,84.8%,86.0%,83.9%,84.4%;with JXA1(lineage 8)was 96.6%,84.4%,86.3%,83.1%,84.0%;85.7%,93.4%,91.9%,93.7%,93.8% with NADC30(lineage 1);86.5%,82.4%,83.0%,81.6%,82.0%with QYYZ(lineage 3);89.0%,85.2%,85.3%,85.0%,85.3% with VR2332(lineage 5),respectively.Analysis of the genetic evolution of the ORF5 gene and the whole gene showed that 180049-1 strain belongs to the lineage 8,and 180770-16,180546-27,180450-1,180253-5 strain belonging to the NADC30-like subgroup of lineage 1.The results of the recombination analysis showed that180450-1 strain may be recombined with NADC30 and VR2332-like strains,and 180049-1,180770-16,180546-27,180253-5 may be recombined with NADC30 and HP-PRRSV-like strains.The results of this study provide a reference for evaluating the recombination,evolution and prevention of PRRSV epidemic strains.