Proteomic adaptation of the hypervirulent pandemic Vibrio parahaemolyticus ST36 lineage to salinity and temperature stress

Abstract

Vibrio parahaemolyticus is a halophilic Gram-negative bacterium widely distributed in marine and estuarine ecosystems, and a leading cause of seafood-borne gastroenteritis worldwide. Among its genetic lineages, sequence type 36 (ST36) has emerged as a pandemic clone with remarkable environmental persistence and global dissemination. Its pathogenicity is closely associated with environmental conditions, particularly salinity and temperature, which modulate the expression of virulence factors, stress-response proteins, and metabolic pathways. In this study, we investigated the differential protein expression profiles of Vibrio parahaemolyticus under controlled salinity (1 and 3%) and temperature (20 °C, 31 °C, and 37 °C) using a label free-quantitative (LFQ) proteomic approach. Our results demonstrate that the Vibrio parahaemolyticus proteome is dynamically and non-linearly modulated by specific combinations of salt and heat rather than a simple additive effect of these factors. Temperature-salinity interactions drove most expression changes (2,144 proteins), with temperature acting as the primary driver (1,302 proteins). Proteome changes peaked mostly at 31 °C for salinity variations and at 3% salinity for temperature shifts, each affecting ~80% of proteins, though specific responses ultimately depended on the nature of individual proteins. Functionally, protein changes were representative of a shift from relatively balanced cellular metabolism at mild stress conditions toward respiratory remodeling, central-carbon reorganization, ATP production, and redox defense under elevated salinity and temperature. Additionally, virulence-, toxin-, motility-, chemotaxis-, and defense-associated proteins were distributed across several trend clusters. Overall, the proteomic patterns detected in Vibrio parahaemolyticus in response to temperature and salinity fluctuations reveal a coordinated regulation of virulence, stress-response, and metabolic proteins that underpins its ecological fitness. Beyond these biological insights, the proteomic workflow employed provides a robust methodological framework for studying bacterial stress adaptation. Ultimately, these findings deepen our understanding of the pathogen dynamics under climate change and for improving seafood safety and risk management. Future research is warranted to experimentally validate the molecular pathways identified and confirm their functional roles in adaptation.