2025 Volume 8 Issue 1 Pages 9-17
Iron is an essential nutrient for bacterial survival. Vibrio alginolyticus is a pathogenic Vibrio species that produces vibrioferrin, a cognate siderophore for efficient iron acquisition in iron-limited environments. Many bacteria have developed mechanisms to utilize xenosiderophores produced by other microorganisms, in addition to using self-produced siderophores for iron acquisition. In this study, we found through a homology search using the whole genome sequence of V. alginolyticus NBRC 15630 that this bacterium has genes similar to those involved in the utilization of hydroxamate-based xenosiderophores, desferri-ferrichrome (DFC), desferrioxamine B (DFOB), and aerobactin (AERO), possessed by V. parahaemolyticus, V. cholerae, and V. vulnificus. In growth assays using an iron-limiting medium supplemented with each xenosiderophore, it was found that the N646_3157 (fhuA1), N646_0489 (fhuA2), N646_0777 (desA), and N646_4356 (iutA) are outer membrane receptor genes involved in the utilization of DFC, DFOB, and AERO and N646_3158-3160 (fhuC1D1B1), and N646_0486-0488 (fhuC2D2B2) are ATP-binding cassette transporter genes for both DFC and DFOB. Additionally, we demonstrated by reverse transcriptase-quantitative PCR and electrophoretic mobility shift assay that the fhuC2D2B2A2 genes, which were newly identified in pathogenic Vibrio species, are an operon whose expression is probably regulated by Fur in response to iron availability.
