Response mechanism of Vibrio parahaemolyticus at high pressure revealed by transcriptomic analysis.

Abstract

Vibrio parahaemolyticus is a common pathogen in aquatic products, such as shellfishes. Laboratory-based simulated studies demonstrated that V. parahaemolyticus can tolerate high hydrostatic pressure (HHP) up to 20MPa. However, the molecular mechanisms of high-pressure adaptation remain unclear. Herein, we analyzed the physiological changes and transcriptomic responses of V. parahaemolyticus ATCC 17,802 under HHP conditions to determine the possible survival mechanisms. Under HHP conditions, the morphology of V. parahaemolyticus was notably changed exhibiting the coccoid microbial cells. The transcriptome analysis revealed that there were 795 differentially expressed genes (DEGs) under the 20MPa condition, including 406 upregulated DEGs and 389 downregulated DEGs. Most of the downregulated DEGs encoded proteins related to energy metabolism, such as citrate synthase (gltA), pyruvate kinase (pyk), and glyceraldehyde-3-phosphate dehydrogenase (gapA). Many of the upregulated DEGs encoded proteins related to adhesion and virulence factors, such as RNA polymerase σ factor (rpoE), L-threonine 3-dehydrogenase, and bacterial nucleotide signal c-di-GMP (WU75_RS02745 and WU75_RS07185). In our proposed mechanism model, V. parahaemolyticus responds to HHP stress through RNA polymerase σ factor RpoE. These findings indicate that V. parahaemolyticus cells may adopt a complex adaptation strategy to cope with HHP stress. KEY POINTS: •The transcriptomic response of Vibrio parahaemolyticus under HHP conditions was studied for the first time. •V. parahaemolyticus may adopt a complex adaptation strategy to cope with HHP stress. •ToxRS and RpoE played an important role in sensing and responding the HHP signal.