Quorum sensing and iron regulate a two-for-one siderophore gene cluster in .

TitleQuorum sensing and iron regulate a two-for-one siderophore gene cluster in .
Publication TypeJournal Article
Year of Publication2018
AuthorsMcRose, DL, Baars, O, Seyedsayamdost, MR, Morel, FMM
JournalProc Natl Acad Sci U S A
Volume115
Issue29
Pagination7581-7586
Date Published2018 Jul 17
ISSN1091-6490
Abstract

The secretion of small Fe-binding molecules called siderophores is an important microbial strategy for survival in Fe-limited environments. Siderophore production is often regulated by quorum sensing (QS), a microbial counting technique that allows organisms to alter gene expression based on cell density. However, the identity and quantities of siderophores produced under QS regulation are rarely studied in the context of their roles in Fe uptake. We investigated the link between QS, siderophores, and Fe uptake in the model marine organism where QS is thought to repress siderophore production. We find that uses a single QS- and Fe-repressed gene cluster to produce both cell-associated siderophores (amphiphilic enterobactins) as well as several related soluble siderophores, which we identify and quantify using liquid chromatography-coupled (LC)-MS as well as tandem high-resolution MS (LC-HR-MS/MS). Measurements of siderophore production show that soluble siderophores are present at ∼100× higher concentrations than amphi-enterobactin and that over the course of growth decreases amphi-enterobactin concentrations but accumulates soluble siderophores. Fe radio-tracer uptake experiments demonstrate that these soluble siderophores play a significant role in Fe uptake and that the QS-dictated concentrations of soluble siderophores in stationary phase are near the limit of cellular uptake capacities. We propose that cell-associated and soluble siderophores are beneficial to in different environmental and growth contexts and that QS allows to exploit "knowledge" of its population size to avoid unnecessary siderophore production.

DOI10.1073/pnas.1805791115
Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID29954861
PubMed Central IDPMC6055174