Bioinformatics Analysis on S1 Gene of Four Porcine Epidemic Diarrhea Virus Strains

To analyse the genetic variation of porcine epidemic diarrhea virus（PEDV),one pair of primers was designed and RT-PCR was used to amplify the S1 gene epitope sequences of 4 PEDV field strains.Phylogenetic analysis showed that 4 strains were closely related to each other and belonged to the second group,and the Hunan and Henan isolates had a close relationship with JXGZ2013,GDZQ2012,GDZQ2014 strains,with the nucleotide homologies at 98.3% to 98.7%;Shanghai strain had a closed relationship with BJ-2011 strain and LZW isolates,with the higher homology at about 98.7%;Fujian isolates had a close relationship with strain of American in 2013,Japanese and Taiwan variation of China with the nucleotide homology at 99.0% to 99.5%;These results showed that a rapid variation and evolution of PEDV strains occurred in recent years,and linear B-cell epitope analysis showed that the threshold values at site 265 to 278 amino acid of 4 filed strains were higher than that of vaccine strains.The epitope differences indicated a possible of infectious that cause of patterns of epidemiology of PEDV.