Construction and biological characterization of Vibrio mimicus's metalloprotease gene PrtV-deletion strain

Abstract:

[Background] Studies have found that PrtV gene encodes a metalloprotease containing polycystic kidney disease (PKD) domains, which plays an important role in the pathogenic process of various bacteria. Vibrio mimicus is one of the important pathogenic bacteria that infects a variety of aquatic animals, but the role of PrtV gene in the pathogenicity of V. mimicus is not clear. [Objective] To explore the effect of PrtV gene on the pathogenicity-related biological characteristics of V. mimicus. [Methods] The natural transformation method was used to construct the PrtV gene-deletion strain (ΔPrtV) of V. mimicus, and the complement strain (ΔPrtV/pPrtV) was constructed by electrotransformation after gene combined with plasmid. The mutant's biochemical characteristics, biofilm formation, self-aggregation ability, extracellular product protease activity, pathogenicity, and cytotoxicity were analyzed.[Results] As compared with wild stains, the growth, biofilm formation, self-aggregation ability, and lecithinase activity of the ΔPrtV were hardly changed, but the physicochemical properties of decomposing urea, glycine, coumarinate, ornithine, and lysine were changed. The extracellular product protease activity and cytotoxicity of ΔPrtV were significantly decreased (P<0.05), and the pathogenicity to hybrid catfish was decreased by 10 times.[Conclusion] PrtV gene is related to various biological functions such as cytotoxicity and pathogenicity of V. mimicus. The results provide a basis for further analysis of the features of PrtV gene and its pathogenic mechanism in V. mimicus.