Translator Disclaimer
1 September 2011 Phylogenetic Analysis of S1 Gene of Infectious Bronchitis Virus Isolates from China
Author Affiliations +

Between 2006 and 2009, seven strains of infectious bronchitis (IB) virus (IBV) were isolated from vaccinated chicken flocks on different chicken farms in China. The pathogenic characters of seven IBV strains were assessed. Each of the seven strains was infective to the test chickens and could induce an immune response. The results from chicken embryo cross-neutralization assays showed that these strains were antigenically distinct from classic IBV strains of H120, M41, Conn, and Gray. Compared to H120 vaccine strain, point mutation, short insertion, and deletion occurred at many positions in the S1 protein of the seven strains. Five of the seven strains had the motif (HRRRR), which was identical to that of the epidemic IBV strains in China. Two new motifs (HRLRR and RRIRR) emerged in the isolated strains. The homology of the nucleotide and amino acid sequences of the S1 gene among the seven isolates was 81.7%–99.7% and 79.0%–99.4%, respectively. These seven strains were also genetically different from the vaccine strains and non-China IBV strains but closely related to large numbers of Chinese strains. The seven isolates and 36 reference IBV strains were clustered into six distinct groups (I–VI). The seven strains were categorized into groups I, II, and III, forming a big phylogenetic branch, which is closely related to Chinese IBVs, whereas the vaccine strains belonging to group VI are genetically distant from groups I, II, and III. The results from this study indicate that different IBV strains cocirculate in the chicken population in China.

American Association of Avian Pathologists
Fang Yan, Yujun Zhao, Wenbin Yue, Yao J, Lihua Lv, Wenhui Ji, Xuying Li, Fengbo Liu, and Qian Wu "Phylogenetic Analysis of S1 Gene of Infectious Bronchitis Virus Isolates from China," Avian Diseases 55(3), 451-458, (1 September 2011).
Received: 5 July 2010; Accepted: 1 March 2011; Published: 1 September 2011

Get copyright permission
Back to Top