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Debeljak P, Bayer B, Sun Y, Herndl GJ, Obernosterer I. Seasonal patterns in microbial carbon and iron transporter expression in the Southern Ocean. Microbiome 2023; 11:187. [PMID: 37596690 PMCID: PMC10439609 DOI: 10.1186/s40168-023-01600-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 06/16/2023] [Indexed: 08/20/2023]
Abstract
BACKGROUND Heterotrophic microbes in the Southern Ocean are challenged by the double constraint of low concentrations of organic carbon (C) and iron (Fe). These essential elements are tightly coupled in cellular processes; however, the prokaryotic requirements of C and Fe under varying environmental settings remain poorly studied. Here, we used a combination of metatranscriptomics and metaproteomics to identify prokaryotic membrane transporters for organic substrates and Fe in naturally iron-fertilized and high-nutrient, low-chlorophyll waters of the Southern Ocean during spring and late summer. RESULTS Pronounced differences in membrane transporter profiles between seasons were observed at both sites, both at the transcript and protein level. When specific compound classes were considered, the two approaches revealed different patterns. At the transcript level, seasonal patterns were only observed for subsets of genes belonging to each transporter category. At the protein level, membrane transporters of organic compounds were relatively more abundant in spring as compared to summer, while the opposite pattern was observed for Fe transporters. These observations suggest an enhanced requirement for organic C in early spring and for Fe in late summer. Mapping transcripts and proteins to 50 metagenomic-assembled genomes revealed distinct taxon-specific seasonal differences pointing to potentially opportunistic clades, such as Pseudomonadales and Nitrincolaceae, and groups with a more restricted repertoire of expressed transporters, such as Alphaproteobacteria and Flavobacteriaceae. CONCLUSION The combined investigations of C and Fe membrane transporters suggest seasonal changes in the microbial requirements of these elements under different productivity regimes. The taxon-specific acquisition strategies of different forms of C and Fe illustrate how diverse microbes could shape transcript and protein expression profiles at the community level at different seasons. Our results on the C- and Fe-related metabolic capabilities of microbial taxa provide new insights into their potential role in the cycling of C and Fe under varying nutrient regimes in the Southern Ocean. Video Abstract.
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Affiliation(s)
- Pavla Debeljak
- Laboratoire d'Océanographie Microbienne (LOMIC), CNRS, Sorbonne Université, Banyuls/Mer, F-66650, France.
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, Vienna, 1030, Austria.
- SupBiotech, Villejuif, France.
| | - Barbara Bayer
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, Vienna, 1030, Austria
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, Vienna, 1030, Austria
| | - Ying Sun
- Laboratoire d'Océanographie Microbienne (LOMIC), CNRS, Sorbonne Université, Banyuls/Mer, F-66650, France
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, Vienna, 1030, Austria
- Department of Marine Microbiology and Biogeochemistry, NIOZ (Royal Netherlands Institute for Sea Research), Den Burg, 1790 AB, The Netherlands
- Vienna Metabolomics Center, University of Vienna, Djerassiplatz 1, Vienna, 1030, Austria
| | - Ingrid Obernosterer
- Laboratoire d'Océanographie Microbienne (LOMIC), CNRS, Sorbonne Université, Banyuls/Mer, F-66650, France
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