Effects of type VI secretion system 2 core component VgrG on the pathogenicity of avian Escherichia coli

Abstract:

[Objective] To determine the role of type VI secretion system 2 (T6SS2) core component VgrG in avian pathogenic Escherichia coli (APEC), we detected the biological characteristics and pathogenicity of APEC vgrG gene mutant strain. [Methods] We constructed the vgrG gene mutant strain and complementary strain of APEC DE719 by the Red recombination system and plasmid pSTV28. Then we analyzed the growth curve, motility, biofilm formation, adhesion and invasion capacity to DF-1 cells and virulence to duck of wild-type strain, mutant strain and complementary strain. [Results] The inactivation of vgrG gene did not affect the growth and motility, nor the biofilm formation of APEC. The vgrG gene mutant showed significantly decreased survival capacity and attenuated virulence in ducks. However, the adhesion capacity to DF-1 cells increased. [Conclusion] T6SS2 core component VgrG was involved in the process of APEC infection, which would help us to comprehensive understand the pathogenicity of APEC.

Key words:Avian pathogenic Escherichia coli, vgrG gene, Pathogenicity