Abstract: In this study, the genes encoding main structural proteins and 3′ untranslated region (UTR) of a commercial domestic vaccine strain H52 and a commercial foreign vaccine strain H52 of infectious bronchitis virus (IBV) were obtained by RT-PCR, then were cloned and sequenced respectively. The sequence analyses showed the genetic information of S1 gene, M gene, N gene and 3′UTR of domestic vaccine strain H52 was remarkably different from that of foreign H52 strain and that of published sequences of H52 strain. Compared with foreign H52 strain, this domestic H52 strain was genetically closer with M41 strain and was located in the same branch of phylogenetic tree based on the sequences of main structural protein genes. The results strongly suggested that it was necessary to build genetic information archives of seed stock of IBV vaccine strains.

Key words: infectious bronchitis virus (IBV), spike 1 (S1) gene, membrane (M) gene, nucleocapsid(N) gene, 3′ untranslated region (UTR)