Genomic analysis of one Chinese strain YS07 of infectious bursal disease virus reveals unique genetic diversity.

Abstract

The complete genome sequence of infectious bursal disease virus (IBDV) YS07 strain with low mortality isolated from Guangdong province of China in 2007 was reported in this study. The genome sequences and deduced amino acid (aa) sequences of YS07 were compared with that of previously reported IBDV strains. Phylogenetic analyses based on the deduced aa sequences of VP5, polyprotein, and VP1 protein revealed that YS07 bears its origin from European very virulent (vv) IBDV strains. Multiple aa sequences alignment revealed that YS07 contained a diversified genetic composition being characteristic to vv, variant, classical, and attenuated IBDV strains as well as its own unique ones. Our findings suggest that IBDV strains in China may gradually experience adaptive evolution due to immune pressure from intensive vaccination and demonstrate that the determination and analysis of full genome sequences is a valuable tool for studying the relationship between genetic composition and pathogenicity of IBDV strains.