Novel quorum-sensing inhibitor peptide SF derived from Penaeus vannamei myosin inhibits biofilm formation and virulence factors in Vibrio parahaemolyticus

Abstract

Vibrio parahaemolyticus is a prevalent pathogen found in seafood. In this pathogen, biofilm production and virulence are regulated by the AI-2/LuxS quorum sensing (QS) system. However, little is known about any bioactive peptides that specifically target the AI-2/LuxS QS system in V. parahaemolyticus. In this study, a novel quorum-sensing inhibitor (QSI) — peptide Ser-Phe (SF) derived from hydrolyzed Penaeus vannamei myosin — was screened using molecular docking analysis. At sub-inhibitory concentrations (0.2, 0.6, 0.8, and 1.0 mg/mL), peptide SF effectively inhibited AI-2 activity and biofilm formation in V. parahaemolyticus (inhibition rate: 16.53–55.65% and 13.37–56.73%, respectively). Scanning electron microscopy demonstrated that biofilm structure was disrupted in V. parahaemolyticus treated with peptide SF. Additionally, 1.0 mg/mL peptide SF significantly decreased the secretion of extracellular polysaccharides (inhibition rate: 51.50%), lecithinase (36.51%), protease (39.03%), and diastase (44.93%) and inhibited swarming (49.06%) and swimming behavior (39.00%) in V. parahaemolyticus. The RT-qPCR showed that peptide SF could downregulate QS-related genes (luxS, luxP, aphA, and opaR), virulence factor-related genes (flaA, flgM, and toxR), and biofilm-related genes (cpsA and mshA) in V. parahaemolyticus. These results indicated that peptide SF may serve as a novel QSI for controlling biofilm formation and virulence factors production in V. parahaemolyticus.