China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (3): 1093-1106.doi: 10.16431/j.cnki.1671-7236.2023.03.024

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Phylogenetic Evolution and Epitope Analysis of Pseudorabies Virus Guizhou Isolates and Vaccine Strains

ZHANG Jingxu1, XU Yu1,2, LIANG Haiying1, ZENG Zhiyong1, TANG Deyuan1, WANG Bin1, XU Songping1, WAN Juan1, ZHU Yang1   

  1. 1. College of Animal Science, Guizhou University, Guiyang 550025, China;
    2. Chongqing Health Forever Biotechnology Co., Ltd., Chongqing 402460, China
  • Received:2022-10-24 Online:2023-03-05 Published:2023-03-02

Abstract: 【Objective】 This study was aimed to understand the molecular characteristics of Pseudorabies virus (PRV) strains and vaccine strains in Guizhou province,the genetic evolution of PRV variants in Guizhou province and the antigenic differences between PRV strains and vaccine strains were investigated.【Method】 gB,gC,gD genes of 5 PRV strains isolated from Guizhou province from 2015 to 2021 and commercial vaccine strains (C strains and HB2000 strains) were cloned and sequenced by molecular cloning technology and bioinformatics technology.Using the sequences of two PRV Guizhou strains in the sequence library of our laboratory and the vaccine strains registered on GenBank,systematic genetic evolution and differential analysis of B cell linear antigen epitopes were conducted.【Result】 The results showed that the genome-wide nucleotide similarities of gB,gC and gD genes of the 7 Guizhou strains and vaccine strains were 98.1% to 100%,94.7% to 100% and 98.8% to 100%,respectively.The genome-wide amino acid similarities of gB,gC and gD genes of the 7 Guizhou strains and vaccine strains were 96.4% to 100%,90.9% to 100% and 97.0% to 100%,respectively.Amino acid replacement analysis showed that there were 56,68 and 23 amino acid sites differences in gB,gC and gD genes between the 7 PRV Guizhou strains and vaccine strains,among which the amino acid sites of gC gene were the most different.GZQX2017 strain lacked gE gene.In the genetic evolution tree,GZQX2017 strain and Bartha-K61,Becker,NIA3 and other foreign strains were located in the same large evolutionary branch,belonging to PRV typeⅠ.The remaining six Guizhou strains inserted an aspartic acid (D) at the 48th and 496th positions respectively in gE gene,which was in line with the genetic characteristics of the epidemic variant,and located in another major evolutionary branch with the domestic epidemic PRV variant,belonging to PRV type Ⅱ.When the whole genome of GZQX2017 strain gB,gC and gD genes were used as target genes,Bartha-K61 strain was used as the main parent and Fa strain was used as the secondary parent,both gB and gC genes could detect the recombinant signal,but the recombinant signal of gD gene was not obvious.Compared with Bartha-K61 strain,there were differences in the number and sites of gB,gC and gD protein epitopes.【Conclusion】 Among the 7 PRV strains in Guizhou,GZQX2017 belonged to PRV type Ⅰ with vaccine Bartha-K61 and C strains. GZQX2017 might be the natural deletion of gE gene produced by recombination with Bartha-K61 as the main parent,which was expected to be used as a candidate vaccine strain for further study.The other 6 strains from Guizhou,Fa strain and HB2000 strain belonged to PRV type Ⅱ,which had the epidemic characteristics of epidemic mutant strains.This study was of great significance for understanding the molecular characteristics of PRV strains prevalent in Guizhou province,China.

Key words: Porcine pseudorabies virus (PRV); variant strain; genetic evolution; antigenic epitope; recombination signal

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