Novel insights into the taxonomic diversity and molecular mechanisms of bacterial Mn(III) reduction
Novel insights into the taxonomic diversity and molecular mechanisms of bacterial Mn(III) reduction
Summary Soluble ligand-bound Mn(III) can support anaerobic microbial respiration in diverse aquatic environments. Thus far, Mn(III) reduction has only been associated with certain Gammaproteobacteria. Here, we characterized microbial communities enriched from Mn-replete sediments of Lake Matano, Indonesia. Our results provide the first evidence for biological reduction of soluble Mn(III) outside the Gammaproteobacteria. Metagenome assembly and binning revealed a novel betaproteobacterium, which we designate “Candidatus Dechloromonas occultata.” This organism dominated the enrichment and expressed a porin-cytochrome c complex typically associated with iron-oxidizing Betaproteobacteria and a novel cytochrome c-rich protein cluster (Occ), including an undecaheme putatively involved in extracellular electron transfer. This occ gene cluster was also detected in diverse aquatic bacteria, including uncultivated Betaproteobacteria from the deep subsurface. These observations provide new insight into the taxonomic and functional diversity of microbially-driven Mn(III) reduction in natural environments. Originality-Significance StatementRecent observations suggest that Mn(III)-ligand complexes are geochemically important in diverse aquatic environments. Thus far, microbially-driven Mn(III) reduction has only been associated with Gammaproteobacteria encoding three-component outer-membrane porin-cytochrome c conduits. Here, we demonstrate that Betaproteobacteria dominate in abundance and with respect to protein expression during biologically-mediated Mn(III) reduction in an enrichment culture from an anoxic lacustrine system. Using metaproteomics, we detect for the first time that Betaproteobacteria express a two-component porin-cytochrome c conduit, and an uncharacterized extracellular undecaheme (11-heme) c-type cytochrome. Although this is the first definitive report of an undecaheme within the Betaproteobacteria, we find evidence that they are widespread in uncultivated strains. These results widen the phylogenetic diversity of Mn(III)-reducing bacteria, and provide new insights into potential molecular mechanisms for soluble Mn(III) reduction
Szeinbaum Nadia、Cavazos Amanda R.、Crowe Sean A.、Stewart Frank J.、Reinhard Christopher T.、Glass Jennifer B.、Nunn Brook L.、DiChristina Thomas J.
School of Biological Sciences, Georgia Institute of Technology||School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta||NASA Astrobiology Institute, Alternative Earths TeamSchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, AtlantaSchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta||Department of Microbiology & Immunology and Department of Earth, Ocean, & Atmospheric Sciences, University of British ColumbiaSchool of Biological Sciences, Georgia Institute of Technology||Department of Microbiology and Immunology, Montana State UniversitySchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta||NASA Astrobiology Institute, Alternative Earths TeamSchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta||NASA Astrobiology Institute, Alternative Earths TeamDepartment of Genome Sciences, University of WashingtonSchool of Biological Sciences, Georgia Institute of Technology
微生物学环境科学理论分子生物学
Szeinbaum Nadia,Cavazos Amanda R.,Crowe Sean A.,Stewart Frank J.,Reinhard Christopher T.,Glass Jennifer B.,Nunn Brook L.,DiChristina Thomas J..Novel insights into the taxonomic diversity and molecular mechanisms of bacterial Mn(III) reduction[EB/OL].(2025-03-28)[2025-05-25].https://www.biorxiv.org/content/10.1101/695007.点此复制
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