Iron is an essential element for life and plays a pivotal role in bacterial pathogens. It is required for the respiratory chain and as a co-factor. However, iron overload is toxic, causing a dysregulated oxidative response, thus iron uptake is tightly regulated. Bacterial pathogens can sequester iron from the host protein, and outside of the host, like in marine environments, bacteria have to scaveng ing for this limited and essential nutrient. Moritella
viscosa is a marine psychrophilic Gram-negative pathogen that causes winter ulcerative disease in several fish species. Here, we describe for the first time the M. viscosa iron uptake mechanism and the regulatory network in response to iron limited conditions.
Outer membrane protein profiles of M. viscosa grown under iron-rich and iron-limited conditions revealed specific genes related to iron-limitation response . Transcriptome analyses showed that 77 genes were diysregualted . Heme, ferrous iron, maganase , tugsten, hydroxamate siderophores transporters,
and genes related to oxidative stress were up-regulated. These findings provide a comprehensive analysis of the transcriptional response of M. viscosa, adding relevant understanding of the gene regulatory network of this pathogen and revealing target genes that can aid to the development of effective therapeutic strategies against this important fish pathogen.