Proteomic characterization of Tenacibaculum dicentrarchi under iron limitation reveals an upregulation of proteins related to iron oxidation and reduction metabolism, iron uptake systems and gliding motility

A strategy for vaccine design involves identifying proteins that could be involved in pathogen–host interactions. The aim of this proteomic study was to determine how iron limitation affects the protein expression of Tenacibaculum dicentrarchi, with a primary focus on virulence factors and proteins associated with iron uptake. The proteomic analysis was carried out using two strains of T. dicentrarchi grown under normal (control) and iron-limited conditions, mimicking the host environment. Our findings revealed differences in the proteins expressed by the type strain CECT 7612^T and the Chilean strain TdCh05 of T. dicentrarchi. Nonetheless, both share a common response to iron deprivation, with an increased expression of proteins associated with iron oxidation and reduction metabolism (e.g., SufA, YpmQ, SufD), siderophore transport (e.g., ExbD, TonB-dependent receptor, HbpA), heme compound biosynthesis, and iron transporters under iron limitation. Proteins involved in gliding motility, such as GldL and SprE, were also upregulated in both strains. A negative differential regulation of metabolic proteins, particularly those associated with amino acid biosynthesis, was observed under iron limitation, reflecting the impact of iron availability on bacterial metabolism. Additionally, the TdCh05 strain exhibited unique proteins associated with gliding motility machinery and phage infection control compared to the type strain. These groups of proteins have been identified as virulence factors within the Flavobacteriaceae family, including the genus Tenacibaculum. These results build upon our previous report on iron acquisition mechanisms and could lay the groundwork for future studies aimed at elucidating the role of some of the described proteins in the infectious process of tenacibaculosis, as well as in the development of potential vaccines.