Project description:This project was designed to observe changes in proteins expression and toxicity proteins expression of Aeromonas hydrophila under normal and iron restriction conditions.
Project description:The emerging foodborne pathogen, Aeromonas hydrophila, co-infects humans and animals, especially fish, threatening aquacultural production and public health. Previously we found that Scatophagus argus, a widely cultivated fish species with high economic value, exhibited enhanced growth but increased susceptibility to A. hydrophila infection under freshwater conditions compared to seawater conditions. However, the exact mechanisms involved remain unclear.Our study demonstrated that enhanced virulence of A. hydrophila 201416 isolated from S. argus induced by increasing salinity was associated with altered quorum sensing-related gene expression and regulated behaviors. Results from virulence assays combining phenotypic characterization indicated that increased salinity (from 0 to 35 g/L NaCl) impeded Ah201416 infection of S. argus, a trend aligning with increased biofilm mass and swimming motility, but opposite to bacterial growth. RNA-sequencing and quantitative reverse transcriptional PCR analysis confirmed significant upregulation of genes related to flagellar assembly (flgB, flgH, flgC, flgI, flhA, and fliA), bacterial secretion (HlyD and Ahh1), and quorum sensing (AhyR, LuxO, and LuxE) of Ah201416 in response to elevated salinity. These findings suggested that increased salinity not merely enhanced the virulence of Ah201416 but bolstered the resistance of S. argus, thereby mitigating its susceptibility. This study provides further insights into the microbial risks associated with A. hydrophila in aquacultural production, which is critical to developing appropriate prevention and control strategies and ensuring safe seafood supply.
