Genetic Variability and Recombination of the NSP2 Gene of PRRSV-1 Strains in China from 1996 to 2022

Abstract

Porcine reproductive and respiratory syndrome (PRRS) has been present in China for over 20 years. Due to the continuous mutation of PRRS virus (PRRSV), it causes significant economic losses to the pig industry annually. This study aimed to understand the genetic variation of the PRRSV-1 NSP2 gene in China. A total of 69 PRRSV-1 NSP2 strains, consisting of 25 Chinese and 44 foreign strains, were collected and their nucleotide and amino acid homology were analyzed. Results indicated that the nucleotide homology of NSP2 ranged 42.1–97.0%, while the amino acid homology ranged from 59.4–100.0%. Multiple sequence alignments of NSP2 amino acids from the 69 PRRSV-1 strains were conducted to compare differential sites of NSP2 amino acids between PRRSV-1 and PRRSV-2. The study revealed that PRRSV-1 had more missing and replaced sites compared to PRRSV-2. A phylogenetic analysis of the NSP2 sequence of 90 PRRSV strains revealed that the genetic relationships between BJEU06-1-like and NMEU09-1-like are relatively close, but far from Amervac-like and HKEU-16-like. Additionally, recombinant analysis showed that four recombination events occurred in the 90 selected PRRSVs, with two occurring in the Chinese PRRSV-1 NSP2 sequence. These findings provide a deeper understanding of the prevalence of PRRSV-1 in China over the past 20 years and will serve as a theoretical basis for the evolution and epidemiology of PRRSV.The abstract serves both as a general introduction to the topic and as a brief, non-technical summary of the main results and their implications. Authors are advised to check the author instructions for the journal they are submitting to for word limits and if structural elements like subheadings, citations, or equations are permitted.