Transcriptomic Analysis of the Dynamic Formation Mechanism of Vibrio parahaemolyticus Biofilm

To investigate the mechanism of biofilm formation in Vibrio parahaemolyticus, its physiological characteristics were examined and the regulation of gene expression during biofilm formation was studied transcriptomic sequencing. Two strains of V. parahaemolyticus (ATCC 17802 and VP-0) that differ in their biofilms were evaluated for their physiological indexes such as extracellular polysaccharides, extracellular proteins, the signaling molecule autoinducer-2 (AI-2), cell permeability, and biofilm microscopic morphology, and the dynamic formation process of biofilm was investigated. The results showed that the biofilm formation process of the tested strains involved reversible adhesion (from 0 to 12 h), irreversible adhesion and micro-colony formation (from 12 to 48 h), maturation (from 48 to 72 h), and dissociation (from 72 to 144 h). The secretion rates of extracellular polysaccharides and proteins at the biofilm maturation stage of ATCC 17802 were 1.67 and 2.3 times higher than those of VP-0, respectively. The difference in signaling molecule content during biofilm formation was not significant (P > 0.05), and laser confocal scanning microscopy (LCSM) showed that ATCC 17802 had a greater degree of aggregation. Based on the results of transcriptomic sequencing, 802, 1061, and 267 significantly differentially expressed genes were identified in three treatment groups (72 vs 8 h, 48 vs 8 h, and 72 vs 48 h), of which 506, 655 and 96 differentially expressed genes were down-regulated and 296, 406 and 171 differentially expressed genes were up-regulated, respectively. These differences were mainly involved in energy metabolism, flagellar system, transport system, and other aspects related to biofilm formation. The findings obtained in this study provide a theoretical basis for gene expression regulation during the dynamic formation of V. parahaemolyticus biofilm.