Construction and characterization of Gallibacterium anatis ΔompWΔgtxA double deletion strain

Abstract:

Gallibacterium anatis is a conditional pathogen common in poultry production, and causes the laying hen genital tract diseases, resulting in decreased egg production. [Objective] To understand the biological characteristics and pathogenicity of the virulence factor RTX-like toxin GtxA and outer membrane protein W of G. anatis. [Methods] Based on the G. anatis OmpW gene deletion strain, we successfully constructed the OmpWgtxA double gene deletion strain by natural transformation. The differences in biological characteristics and virulence between single and double gene deletion strains and parental strain were investigated. [Results] The hemolytic activity of the OmpWgtxA double gene deletion strain was inactivated, while the deletion was stable in vitro and in vivo. Compared with gtxA, ompW single gene deletion strain and parental strain Yu-PDS-RZ-1-SLG, the growth of the double gene deletion strain was not significantly altered, while its adhesion ability and lesions of primary chicken oviduct epithelial cells were decreased to some extent; and its ability to induce apoptosis in cells of chicken oviduct epithelium was lessened; its pathogenicity was also reduced. [Conclusion] GtxA toxin and outer membrane protein W were suggested to play important roles in G. anatis virulence, adhesion to host cells and induction of apoptosis and there may be synergies. This study laid the foundation for further revealing the pathogenesis of G. anatis.