Bacillus subtilis modulates its usage of biofilm-bound iron in response to environmental iron availability.

We report that this B. subtilis strain can accumulate a large quantity of Fe in the biofilm, largely exceeding Fe associated with cells. We also report that only a fraction of biofilm-bound Fe is available for uptake in the absence of other sources of Fe in the vicinity of the biofilm. We observed that availability of environmental Fe modulates the usage of this pool of biofilm-bound Fe. Finally, our data suggest that consumption of biofilm-bound Fe relates to the efficacy of B. subtilis to transport Fe from the environment to the biofilm, possibly through siderophores.Importance Recent evidences suggest that Fe bound to the biofilm could assume at least two important functions; a local source of Fe for uptake and a support to extracellular metabolism such as extracellular electron transfer. Our results show that B. subtilis can use biofilm-bound Fe for uptake only if it does not compromise Fe homeostasis of the biofilm, i.e., maintaining a minimum Fe concentration in the biofilm for extracellular purposes. We propose a theoretical framework based on our results and recent literature to explain how B. subtilis manages biofilm-bound Fe and Fe uptake in response to environmental Fe availability. These results provide important insights into the management of biofilm-bound and environmental Fe by B. subtilis in response to Fe stress. PMID: 32917750 [PubMed - as supplied by publisher]
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research