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ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiological Chemistry and Geomicrobiology
Volume 15 - 2024 |
doi: 10.3389/fmicb.2024.1446596
Iodate Reduction by Marine Aerobic Bacteria
Provisionally accepted- 1 Graduate School of Horticulture, Faculty of Horticulture, Chiba University, Chiba, Japan
- 2 National Institute for Environmental Studies (NIES), Tsukuba, Ibaraki, Japan
Iodate reductase (idr) gene cluster (idrABP1P2) is involved in bacterial iodate (IO3 -) respiration under anaerobic conditions. Putative idr gene clusters are present in both anaerobic and aerobic bacteria; however, the specific physiological roles of idr genes in aerobic bacteria remain unclear. Therefore, in this study, three marine aerobic bacteria with putative idr gene clusters (Roseovarius azorensis, Notoacmeibacter marinus, and Aliiroseovarius sediminilitoris) were grown in the presence of iodate to determine whether they can reduce iodate to iodide (I -). All tested bacteria almost completely reduced 2 mM iodate under static conditions but only reduced 0.1-0.5 mM iodate under shaking conditions. Moreover, the washed cell suspension of R. azorensis reduced iodate only when the cells were pre-grown statically in the presence of iodate. Transcriptional analysis revealed that the expression levels of idrA, idrB, idrP1, and idrP2 genes were upregulated in R. azorensis when the cells were grown statically in the presence of iodate. Specifically, idrA expression was induced by 0.1 µM iodate and was up to 14-fold higher compared to that of the non-iodate control. These results suggest that marine aerobic bacteria reduce iodate under oxygen-limited conditions, and that this capacity is induced by environmentally relevant levels of iodate in seawater. Our results suggest that marine aerobic bacteria contribute to iodide production in marine surface waters, thereby affecting the global iodine cycling and ozone budget.
Keywords: Iodate reduction, iodide production, marine aerobic bacteria, Roseovarius azorensis, IdrABP1P2
Received: 10 Jun 2024; Accepted: 09 Sep 2024.
Copyright: © 2024 Kine, Amachi and Yamamura. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Seigo Amachi, Graduate School of Horticulture, Faculty of Horticulture, Chiba University, Chiba, Japan
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