Construction and characterization of the vscG gene mutant strain of Vibrio parahaemolyticus type Ⅲ secretion system

Abstract:

[Background] Vibrio parahaemolyticus is an important food-borne pathogenic microorganism. Type Ⅲ secretion system (T3SS) plays an important role in the pathogenic process of V. parahaemolyticus. The VscG protein encoded by the vscG gene is a chaperone protein in T3SS. The biological function of vscG gene has not been determined. [Objective] To analysis the effect of the vscG gene on the biological characteristics, a deletion strain and complement strain of the vscG gene were constructed and characterized. [Methods] We constructed the vscG gene mutant strain and complemented strain of POR-1 strain using the homologous recombination method. Then we analyzed the growth characteristics, biofilm formation, motility, hemolytic activity, cells adhesion and cytotoxicity. [Results] Compared with POR-1 strain, the growth characteristics and hemolytic activity of the deletion strain ΔvscG and the complementing strain CΔvscG were not significantly different. The biofilm formation ability of ΔvscG was reduced. The motility was enhanced of ΔvscG as compared with POR-1 and CΔvscG. Cell infection tests showed that the deletion of the vscG gene significantly reduced the adhesion and toxicity of V. parahaemolyticus to HeLa cells. [Conclusion] The vscG gene affects the motility and formation of the biofilm of V. parahaemolyticus, it plays an important role in the adhesion and cytotoxicity to HeLa cells, laying a foundation for further exploring the pathogenic mechanism of T3SS in V. parahaemolyticus.

Key words:Vibrio parahaemolyticus, T3SS, vscG gene, biological characteristics