Isolation and molecular characterization of an avian infectious bronchitis virus variant

To investigate the molecular characteristics and variation of newly isolated infectious bronchitis virus(IBV), the gene2 to gene6 genomic sequences of IBV WF2011 isolated from ovarian tissues of laying hens in Weifang of Shandong were sequenced. The sequence analysis showed that the C terminal sequence of WF2011 had the typical 5'-S-3a-3b-E-M-5a-5b-N-3' gene order and the typical avian coronavirus cleavage site of540RRSRR544in spike protein, as American strains of Gray, Holte, JMK, Conn46 and South Korean SNU8067 strain. Homology analysis and phylogenetic analysis showed that WF2011 had low identities with IBV reference strains. The identities of WF2011 S1 gene with those of other reference strains range from 61.8% to 86.0%. There is relatively far genetic distance between WF2011 and LX4, SAIBK, Mass-like strains. Therefore, WF2011 might be a new variant IBV isolate.