title: Molecular characterization of major structural protein genes of avian coronavirus infectious bronchitis virus isolates in southern china.
abstract: To gain comprehensive genetic information of circulating avian coronavirus infectious bronchitis virus (IBV) isolates in China, analysis of the phylogenetic tree, entropy of the amino acid sequences, and the positive selection as well as computational recombinations of S1, M and N genes of 23 IBV isolates was conducted in the present study. The phylogenetic trees based on the S1, M and N genes exhibited considerably different topology and the CK/CH/LSC/99I-type isolates were the predominant IBVs based on the phylogenetic analysis of S1 gene. Results of entropy of amino acid sequences revealed that the S1 gene had the largest variation; the M gene had less variation than the N gene. Positive selections were detected in not only S1 but also M and N gene proteins. In addition, five S1 gene recombinants between vaccine strain 4/91 and CK/CH/LSC/99I-type field isolate were confirmed. In conclusion, multiple IBV genotypes co-circulated; genetic diversity and positive selections existed in S1, M and N genes; 4/91 vaccine recombinants emerged in China. Our results show that field IBVs in China are continuing to evolve and vaccine strains may have an important role in the appearance of new IBV strains via recombination. In addition, the present study indicates that IBV evolution is driven by both generations of genetic diversity and selection.
authors.affiliation: College of Animal Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China. momeilan@163.com.
authors.forename: Mei-Lan
authors.initials: ML
authors.lastname: Mo
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Bai-Cheng
authors.initials: BC
authors.lastname: Huang
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Fan
authors.forename: Ping
authors.initials: P
authors.lastname: Wei
authors.forename: Tian-Chao
authors.initials: TC
authors.lastname: Wei
authors.forename: Qiu-Ying
authors.initials: QY
authors.lastname: Cheng
authors.forename: Zheng-Ji
authors.initials: ZJ
authors.lastname: Wei
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Lang
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000821:virology*; D001717:Birds; D002681:China; D016000:Cluster Analysis; D018352:Coronavirus Infections / Q000662:veterinary* / Q000821:virology; D014644:Genetic Variation; D005838:Genotype; D001351:Infectious bronchitis virus / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D011995:Recombination, Genetic; D012641:Selection, Genetic; D017386:Sequence Homology, Amino Acid; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D015678:Viral Structural Proteins