Isolation,Identification and Genetic Evolution Analysis of Porcine Epidemic Diarrhea Virus SD20BZ01 Strain in Shandong Province
In order to investigate the genetic evolution characteristics of porcine epidemic diarrhea virus(PEDV)in Shandong Province,PEDV-positive samples collected from a swine farm in Binzhou City of Shandong Province were inoculated with Vero E6 cells,then a strain of PEDV was successfully isolated,then named as SD20BZ01. Viral genome fragments were amplified by RT-PCR to obtain its whole genome sequence through sequencing and splicing,then the homology and genetic evolution relationship were compared with the reference strain registered in GenBank. It was found that,by the analysis of whole genome sequence,the homology of SD20BZ01 and GII-b variants prevalent in China since 2010 was from 97.8% to 98.7%,which was significantly higher than early classical strains like CV777,DR13,SM98 and SD-M. It was determined that SD20BZ01 was belonged to GII-b subtype variants. The genetic evolutionary relationship based on S gene was generally consistent with that based on the whole genome sequence. Compared with CV777,the S protein of SD20BZ01 harbored 10 amino acid mutations in the neutralizing antigen epitope,while was basically consistent with the amino acid sequence of S protein of variants prevalent in recent years,indicating that the rules of variation of GII-b subtype PEDV tended to be stable gradually. A theoretical basis was thus provided for future epidemiological research as well as development of prevention and control strategy against PEDV in Shandong Province.