Novel genotype of infectious bronchitis virus isolated in China

• Published in: Veterinary microbiology Vol. 230; pp. 178 - 186
• Main Authors: Ma, Tianxin, Xu, Liwen, Ren, Mengting, Shen, Jie, Han, Zongxi, Sun, Junfeng, Zhao, Yan, Liu, Shengwang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2019; Elsevier BV
• Subjects: Affinity; Animals; Bronchitis; Chickens; Chickens - virology; China - epidemiology; Coronavirus Infections - epidemiology; Coronavirus Infections - veterinary; Emergence; Genome, Viral; Genomic analysis; Genotype; Genotype & phenotype; Genotypes; Infectious bronchitis virus; Infectious bronchitis virus - genetics; Infectious bronchitis virus - isolation & purification; Phylogeny; Poultry; Poultry Diseases - epidemiology; Poultry Diseases - virology; Recombination; Recombination event; Recombination, Genetic; Respiratory tract; S1 gene; Sequence Analysis, RNA; Serogroup; Serotype; Viruses; China; Genotype; Affinity; Serotype; Infectious bronchitis virus; Recombination event
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2019.01.020

•A novel genotype, designated as GVII-1, has been identified in south China over a 5-year period.•GVII-1 was derived from two recombination events that replaced the spike gene in a GI-18-like virus with an as-yet-unidentified sequence.•GVII-1 represented a novel serotype.•GVII-1 showed a low affinity to the respiratory tract in chickens. Recombination events are known to contribute to the emergence of novel infectious bronchitis virus (IBV) genotypes. In this study, we carried out detailed phylogenetic analysis and sequence comparisons based on 74 complete nucleotide sequences of the IBV S1 gene, including strain I0636/16 and 73 representative sequences from each genotype and lineage. The results showed that strain I0636/16 represented a novel genotype, designated as lineage 1 within genotype VII (GVII-1). Further comparative genomic analysis revealed at least two recombination sites that replaced the spike gene in a lineage 18 within genotype I (GI-18)-like virus with an as-yet-unidentified sequence, likely derived from another IBV strain, resulting a novel serotype with a lower affinity to the respiratory tract in chickens. To the best of our knowledge, this provides the first evidence for recombination leading to replacement of the complete spike gene and the emergence of a novel genotype/serotype with a lower affinity to the respiratory tract in chickens comparing to one of its parental virus ck/CH/LGX/111119. These results emphasize the importance of limiting exposure to novel IBVs that may serve as a source of genetic material for emerging viruses, as well as the importance of IBV surveillance in chicken flocks.