Comparative transcriptomic analysis of pathogenic Vibrio parahaemolyticus YDE17 under iron-limited conditions

Iron plays crucial roles in the growth, virulence, and environmental adaptation of bacterial pathogens. In this study, transcriptomic analysis was performed on the important aquaculture pathogen Vibrio parahaemolyticus grown under normal and iron-limited conditions. A total of 2258 differentially expressed genes (DEGs) were identified, including 1121 upregulated and 1137 downregulated genes. Gene Ontology (GO) analysis revealed that DEGs were mainly enriched in biological processes (BPs) such as peptide metabolic process, polypeptide biosynthetic process, and translation; in contrast, BPs related to signal transduction, bacterial flagellar motility, and peptidase activity were downregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that DEGs involved in oxidative phosphorylation and carbon metabolism were downregulated under iron-limited condition. However, genes associated with iron uptake were significantly upregulated, but the siderophore secretion was reduced after addition of an RND-type efflux pump inhibitor, Phe-Arg-β-naphthylamide dihydrochloride (PAβN). Consistent with transcriptional analysis, V. parahaemolyticus YDE17 exhibited decreased motility and protease activity but enhanced biofilm formation ability under the tested iron-limited condition. Finally, the combined application of PAβN and the supernatant of its antagonist Glutamicibacter sp. ZY1 improved the inhibitory effect on V. parahaemolyticus YDE17, yielding an inhibition rate of 89.51%, while the supernatant alone achieved an inhibition rate of 78.54%. This study not only provides new insights into the effects of iron level on V. parahaemolyticus YDE17 and its adaptive responses, but also offers a novel strategy for controlling Vibrio infections in aquaculture.