Epidemiological survey of porcine rotavirus genotype G9 and the genetic variation analysis of VP7 gene.

To study the variation of porcine rotavirus(PoRV) genotype G9,the VP7 gene sequences of PoRV,which were isolated in different swine breeding farms in 2012,were amplified by RT-PCR technique,sequenced,and evolution analyzed.The results demonstrated that full-length VP7 gene was 1,062 bp,including a 982 bp ORF which encodes 326 amino acids.The VP7 gene shared 91.5% to 99.3% identities with PoRV reference strains.Compared with 99-SP1904,99-SP1542,99-TK2091,99-TK2082 and JP32-4 strain,point mutations were found at positions of 31 nt,56 nt,75 nt,82 nt,191 nt,251 nt with no insertions or deletions.Phylogenetic analysis revealed that VP7 genes from Heilongjiang,Liaoning and Inner Mongolia were similar,but were significantly different from which of Guangxi,Zhejiang,Guizhou and Beijing.These results showed the VP7 gene variations were relevant to the difference of the regions.