In the present study, we report the detection of a novel infectious bronchitis virus lineage within genotypes GVII (GVII-2) in commercial flocks in China since 2008. Virus strains within this lineage have been isolated from different geographic regions in China. S1 genes of these viruses have an intralineage divergence of 0.2%-4.4% nucleotides and 0.1%-7.5% amino acids. The pairwise distances of nucleotide and amino acid sequences based on the S1 subunit between GVII-2 and the closest GVII-1 were 28.3% -28.8% and 28.1%-28.9%, respectively. Complete genomic sequence analysis of the first detected strain, ck/CH/LAH/08I (LAH/08I), suggested that it is derived from recombination events with a genomic backbone of the GI-19 ck/CH/LGS/08I-like strain and distinct S, 3a, and 5a genes. The GVII-2 strain represents a unique serotype that differs from the GVII-1 I0636/16 strain in the same genotype and its deduced parental virus GI-19 I0305/19. Strain LAH/08I not only showed strong tissue tropism in the kidneys of SPF chickens but also exhibited high replication capacities in the trachea, kidney, digestive tract, and immune system of infected chickens, attributed to its pathogenicity in SPF chickens. Strain LAH/08I also showed tropism in the oviducts and the ability to induce cystic oviduct formation in adult chickens after infection in baby chicks.

Keywords: GVII-2; I1134/15; LAH/08I; cystic oviduct; infectious bronchitis virus; nephropathogenicity; serotype.