Li Wansheng, Li Chao, Guo Zhenyang, Xu Hu, Gong Bangjun, Sun Qi, Zhao Jing, Xiang Lirun, Leng Chaoliang, Peng Jinmei, Zhou Guohui, Tang Yandong, Liu Huairan, An Tongqing, Cai Xue-Hui, Tian Zhi-Jun, Wang Qian, Zhang Hongliang
State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan Provincial Engineering Laboratory of Insects Bio-Reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology, Nanyang Normal University, Nanyang, China.
Front Microbiol. 2023 May 31;14:1186322. doi: 10.3389/fmicb.2023.1186322. eCollection 2023.
Porcine reproductive and respiratory syndrome virus (PRRSV) has caused serious economic losses to the pig industry worldwide. During the continuous monitoring of PRRSV, a new PRRSV strain type with novel characteristics was first identified in three different regions of Shandong Province. These strains presented a novel deletion pattern (1 + 8 + 1) in the NSP2 region and belonged to a new branch in sublineage 8.7 based on the ORF5 gene phylogenetic tree. To further study the genomic characteristics of the new-branch PRRSV, we selected a sample from each of the three farms for whole-genome sequencing and sequence analysis. Based on the phylogenetic analysis of the whole genome, these strains formed a new independent branch in sublineage 8.7, which showed a close relationship with HP-PRRSV and intermediate PRRSV according to nucleotide and amino acid homology but displayed a completely different deletion pattern in NSP2. Recombinant analysis showed that these strains presented similar recombination patterns, all of which involved recombination with QYYZ in the ORF3 region. Furthermore, we found that the new-branch PRRSV retained highly consistent nucleotides at positions 117-120 (AGTA) of a quite conserved motif in the 3'-UTR; showed similar deletion patterns in the 5'-UTR, 3'-UTR and NSP2; retained characteristics consistent with intermediate PRRSV and exhibited a gradual evolution trend. The above results showed that the new-branch PRRSV strains may have the same origin and be similar to HP-PPRSV also evolved from intermediate PRRSV, but are distinct strains that evolved simultaneously with HP-PRRSV. They persist in some parts of China through rapid evolution, recombine with other strains and have the potential to become epidemic strains. The monitoring and biological characteristics of these strains should be further studied.
猪繁殖与呼吸综合征病毒（PRRSV）给全球养猪业造成了严重的经济损失。在对PRRSV的持续监测过程中，首次在山东省的三个不同地区鉴定出一种具有新特性的新型PRRSV毒株类型。这些毒株在NSP2区域呈现出一种新的缺失模式（1+8+1），并且基于ORF5基因系统发育树属于亚谱系8.7中的一个新分支。为了进一步研究新分支PRRSV的基因组特征，我们从三个猪场中各选取了一个样本进行全基因组测序和序列分析。基于全基因组的系统发育分析，这些毒株在亚谱系8.7中形成了一个新的独立分支，根据核苷酸和氨基酸同源性，其与高致病性PRRSV（HP-PRRSV）和中等致病性PRRSV显示出密切关系，但在NSP2中呈现出完全不同的缺失模式。重组分析表明，这些毒株呈现出相似的重组模式，所有这些毒株在ORF3区域都与QYYZ发生了重组。此外，我们发现新分支PRRSV在3'-UTR中一个相当保守的基序的117-120位（AGTA）保留了高度一致的核苷酸；在5'-UTR、3'-UTR和NSP2中呈现出相似的缺失模式；保留了与中等致病性PRRSV一致的特征，并呈现出逐渐进化的趋势。上述结果表明，新分支PRRSV毒株可能具有相同的起源，并且与同样从中等致病性PRRSV进化而来的HP-PPRSV相似，但它们是与HP-PRRSV同时进化的不同毒株。它们通过快速进化在中国的某些地区持续存在，与其他毒株发生重组，并有可能成为流行毒株。应对这些毒株的监测和生物学特性进行进一步研究。
