Mechanisms Underlying the Virulence and Intestinal Colonization of the Vibrio alginolyticus HY9901 DctP Protein with Proteomic Analysis

Vibrio alginolyticus as a common pathogen infecting humans and marine animals has become a severe threat to the global mariculture industry. Using liquid chromatography and tandem-mass spectrometry (LC–MS/MS) analysis, comparative proteomics between dctP-deletion (ΔdctP) strain and wild-type V. alginolyticus HY9901 was profiled, and total of 547 differentially expressed proteins (DEPs) were identified. In these DEPs, 310 proteins were upregulated and 237 proteins were downregulated. Comparative proteomics of ΔdctP and wild-type strains identified some important regulated factors of colonization and virulent proteins. The regulated factors of bacterial colonization mainly included LuxR and ToxR (biofilm formation), flagellins (FlaB and FlrB), mannose-sensitive hemagglutinin (MshA) pilus, various substrates of the type II secretion system (EpsD, SecD and SecF) and type IV secretion system (ClpV), quorum sensing systems (LuxR homologous ValR), the virulent heat shock proteins (IbpA and YbeY), lipopolysaccharide LptE, outer membrane proteins (OmpU and TolC), glutamate synthases (GltB and GltD), oligopeptide permease (OppA) and siderophores (IrgA). In our previous study, biological characteristics (swarming motility, biofilm formation, cell adhesion and colonized ability) were significantly decreased and LD50 was significantly increased of ΔdctP compared to wide-type. Taken together, these results suggest that DctP protein plays an important role in controlling biological characteristics through DEPs in this study to finally affecting intestinal colonization and virulence.