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Bowen JL, Spivak AC, Bernhard AE, Fulweiler RW, Giblin AE. Salt marsh nitrogen cycling: where land meets sea. Trends Microbiol 2024; 32:565-576. [PMID: 37827901 DOI: 10.1016/j.tim.2023.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023]
Abstract
Salt marshes sit at the terrestrial-aquatic interface of oceans around the world. Unique features of salt marshes that differentiate them from their upland or offshore counterparts include high rates of primary production from vascular plants and saturated saline soils that lead to sharp redox gradients and a diversity of electron acceptors and donors. Moreover, the dynamic nature of root oxygen loss and tidal forcing leads to unique biogeochemical conditions that promote nitrogen cycling. Here, we highlight recent advances in our understanding of key nitrogen cycling processes in salt marshes and discuss areas where additional research is needed to better predict how salt marsh N cycling will respond to future environmental change.
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Affiliation(s)
- Jennifer L Bowen
- Department of Marine and Environmental Sciences, Northeastern University, 430 Nahant Rd, Nahant, MA, USA.
| | - Amanda C Spivak
- Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA
| | - Anne E Bernhard
- Biology Department, Connecticut College, New London, CT 06320, USA
| | - Robinson W Fulweiler
- Department of Earth and Environment, Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Anne E Giblin
- The Ecosystems Center, Marine Biological Laboratory, MA 02543, USA
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2
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Rolando JL, Kolton M, Song T, Liu Y, Pinamang P, Conrad R, Morris JT, Konstantinidis KT, Kostka JE. Sulfur oxidation and reduction are coupled to nitrogen fixation in the roots of the salt marsh foundation plant Spartina alterniflora. Nat Commun 2024; 15:3607. [PMID: 38684658 PMCID: PMC11059160 DOI: 10.1038/s41467-024-47646-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 04/09/2024] [Indexed: 05/02/2024] Open
Abstract
Heterotrophic activity, primarily driven by sulfate-reducing prokaryotes, has traditionally been linked to nitrogen fixation in the root zone of coastal marine plants, leaving the role of chemolithoautotrophy in this process unexplored. Here, we show that sulfur oxidation coupled to nitrogen fixation is a previously overlooked process providing nitrogen to coastal marine macrophytes. In this study, we recovered 239 metagenome-assembled genomes from a salt marsh dominated by the foundation plant Spartina alterniflora, including diazotrophic sulfate-reducing and sulfur-oxidizing bacteria. Abundant sulfur-oxidizing bacteria encode and highly express genes for carbon fixation (RuBisCO), nitrogen fixation (nifHDK) and sulfur oxidation (oxidative-dsrAB), especially in roots stressed by sulfidic and reduced sediment conditions. Stressed roots exhibited the highest rates of nitrogen fixation and expression level of sulfur oxidation and sulfate reduction genes. Close relatives of marine symbionts from the Candidatus Thiodiazotropha genus contributed ~30% and ~20% of all sulfur-oxidizing dsrA and nitrogen-fixing nifK transcripts in stressed roots, respectively. Based on these findings, we propose that the symbiosis between S. alterniflora and sulfur-oxidizing bacteria is key to ecosystem functioning of coastal salt marshes.
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Affiliation(s)
- J L Rolando
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - M Kolton
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
- French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - T Song
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - Y Liu
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
- The Pennsylvania State University, Department of Civil & Environmental Engineering, University Park, PA, 16802, USA
| | - P Pinamang
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - R Conrad
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - J T Morris
- Belle Baruch Institute for Marine & Coastal Sciences, University of South Carolina, Columbia, SC, 29201, USA
| | - K T Konstantinidis
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
- Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA, 30332, USA
| | - J E Kostka
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA.
- Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA, 30332, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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3
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Crump BC, Bowen JL. The Microbial Ecology of Estuarine Ecosystems. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:335-360. [PMID: 37418833 DOI: 10.1146/annurev-marine-022123-101845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Human civilization relies on estuaries, and many estuarine ecosystem services are provided by microbial communities. These services include high rates of primary production that nourish harvests of commercially valuable species through fisheries and aquaculture, the transformation of terrestrial and anthropogenic materials to help ensure the water quality necessary to support recreation and tourism, and mutualisms that maintain blue carbon accumulation and storage. Research on the ecology that underlies microbial ecosystem services in estuaries has expanded greatly across a range of estuarine environments, including water, sediment, biofilms, biological reefs, and stands of seagrasses, marshes, and mangroves. Moreover, the application of new molecular tools has improved our understanding of the diversity and genomic functions of estuarine microbes. This review synthesizes recent research on microbial habitats in estuaries and the contributions of microbes to estuarine food webs, elemental cycling, and interactions with plants and animals, and highlights novel insights provided by recent advances in genomics.
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Affiliation(s)
- Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA;
| | - Jennifer L Bowen
- Marine Science Center, Department of Marine and Environmental Sciences, Northeastern University, Nahant, Massachusetts, USA;
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4
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Pérez Castro S, Peredo EL, Mason OU, Vineis J, Bowen JL, Mortazavi B, Ganesh A, Ruff SE, Paul BG, Giblin AE, Cardon ZG. Diversity at single nucleotide to pangenome scales among sulfur cycling bacteria in salt marshes. Appl Environ Microbiol 2023; 89:e0098823. [PMID: 37882526 PMCID: PMC10686091 DOI: 10.1128/aem.00988-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/04/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Salt marshes are known for their significant carbon storage capacity, and sulfur cycling is closely linked with the ecosystem-scale carbon cycling in these ecosystems. Sulfate reducers are key for the decomposition of organic matter, and sulfur oxidizers remove toxic sulfide, supporting the productivity of marsh plants. To date, the complexity of coastal environments, heterogeneity of the rhizosphere, high microbial diversity, and uncultured majority hindered our understanding of the genomic diversity of sulfur-cycling microbes in salt marshes. Here, we use comparative genomics to overcome these challenges and provide an in-depth characterization of sulfur-cycling microbial diversity in salt marshes. We characterize communities across distinct sites and plant species and uncover extensive genomic diversity at the taxon level and specific genomic features present in MAGs affiliated with uncultivated sulfur-cycling lineages. Our work provides insights into the partnerships in salt marshes and a roadmap for multiscale analyses of diversity in complex biological systems.
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Affiliation(s)
- Sherlynette Pérez Castro
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
- Crop and Soil Sciences, University of Georgia, Athens, USA
| | - Elena L. Peredo
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, New York, USA
| | - Olivia U. Mason
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida, USA
| | - Joseph Vineis
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, Nahant, Massachusetts, USA
| | - Jennifer L. Bowen
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, Nahant, Massachusetts, USA
| | - Behzad Mortazavi
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Anakha Ganesh
- Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - S. Emil Ruff
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
- Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Blair G. Paul
- Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Anne E. Giblin
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Zoe G. Cardon
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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5
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Vineis JH, Bulseco AN, Bowen JL. Microbial chemolithoautotrophs are abundant in salt marsh sediment following long-term experimental nitrate enrichment. FEMS Microbiol Lett 2023; 370:fnad082. [PMID: 37541957 DOI: 10.1093/femsle/fnad082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/13/2023] [Accepted: 07/25/2023] [Indexed: 08/06/2023] Open
Abstract
Long-term anthropogenic nitrate (NO3-) enrichment is a serious threat to many coastal systems. Nitrate reduction coupled with the oxidation of reduced forms of sulfur is conducted by chemolithoautotrophic microbial populations in a process that decreases nitrogen (N) pollution. However, little is known about the diversity and distribution of microbes capable of carbon fixation within salt marsh sediment and how they respond to long-term NO3- loading. We used genome-resolved metagenomics to characterize the distribution, phylogenetic relationships, and adaptations important to microbial communities within NO3--enriched sediment. We found NO3- reducing sulfur oxidizers became dominant members of the microbial community throughout the top 25 cm of the sediment following long-term NO3- enrichment. We also found that most of the chemolithoautotrophic genomes recovered contained striking metabolic versatility, including the potential for complete denitrification and evidence of mixotrophy. Phylogenetic reconstruction indicated that similar carbon fixation strategies and metabolic versatility can be found in several phylogenetic groups, but the genomes recovered here represent novel organisms. Our results suggest that the role of chemolithoautotrophy within NO3--enriched salt marsh sediments may be quantitatively more important for retaining carbon and filtering NO3- than previously indicated and further inquiry is needed to explicitly measure their contribution to carbon turnover and removal of N pollution.
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Affiliation(s)
- Joseph H Vineis
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, 30 Nahant Road, Nahant, MA 01908, United States
| | - Ashley N Bulseco
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, 30 Nahant Road, Nahant, MA 01908, United States
| | - Jennifer L Bowen
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, 30 Nahant Road, Nahant, MA 01908, United States
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6
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Zhang X, Zhang C, Liu Y, Zhang R, Li M. Non-negligible roles of archaea in coastal carbon biogeochemical cycling. Trends Microbiol 2022; 31:586-600. [PMID: 36567186 DOI: 10.1016/j.tim.2022.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 12/25/2022]
Abstract
Coastal zones are among the world's most productive ecosystems. They store vast amounts of organic carbon, as 'blue carbon' reservoirs, and impact global climate change. Archaeal communities are integral components of coastal microbiomes but their ecological roles are often overlooked. However, archaeal diversity, metabolism, evolution, and interactions, revealed by recent studies using rapidly developing cutting-edge technologies, place archaea as important players in coastal carbon biogeochemical cycling. We here summarize the latest advances in the understanding of archaeal carbon cycling processes in coastal ecosystems, specifically, archaeal involvement in CO2 fixation, organic biopolymer transformation, and methane metabolism. We also showcase the potential to use of archaeal communities to increase carbon sequestration and reduce methane production, with implications for mitigating climate change.
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Affiliation(s)
- Xinxu Zhang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Cuijing Zhang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Yang Liu
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Rui Zhang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Meng Li
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China.
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7
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Mai Y, Peng S, Lai Z, Wang X. Saltwater intrusion affecting NO 2- accumulation in demersal fishery species by bacterially mediated N-cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154371. [PMID: 35259379 DOI: 10.1016/j.scitotenv.2022.154371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
To investigate the underlying effects of saltwater intrusion (SWI) on bottom aquatic ecosystems, a set of environmental parameters and the bacterial community were determined and analyzed by sampling bottom water and surface sediments at the Modaomen waterway of the Pearl River Estuary. Biodiversity of fishery species and their relationship with the environment variables were analyzed together. NO3- and NO2- concentration down-regulation and NH4+ concentration up-regulation in water and sediment were observed along the resulting salinity gradient, indicating that SWI affected N-cycling. Further investigation via 16 s sequencing revealed that taxonomic and functional composition of the bacterial community in the sediment displayed greater discretization than in water, implying that SWI exerted a greater impact on the sedimentary bacterial community. Metagenomic sequencing showed that the sedimentary bacterial community was associated with NO3-, NO2-, and NH4+ transformation under SWI, and that this was driven by salinity and conductivity. Nitrogen metabolism and denitrification related genes were expressed at higher levels in high salinity than in low salinity, consistent with the increased enzymatic activities of NiR and NR. The NO2- concentration in the muscle of six selected fishery species was significantly decreased by 11.15-65.74% (P < 0.05) along the salinity gradient, indicating that SWI reduced NO2- accumulation. The results suggest that SWI alleviates NO2- accumulation in demersal fishery species via bacterial mediation of N-cycling.
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Affiliation(s)
- Yongzhan Mai
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Songyao Peng
- Pearl River Water Resources Research Institute, Guangzhou 510611, China
| | - Zini Lai
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
| | - Xuesong Wang
- Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology, Guangdong Provincial Engineering Research Center for Ambient Mass Spectrometry, Institute of Analysis, Guangdong Academy of Sciences (China National Analytical Center, Guangzhou), Guangzhou 510070, China.
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8
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Seasonal and Zonal Succession of Bacterial Communities in North Sea Salt Marsh Sediments. Microorganisms 2022; 10:microorganisms10050859. [PMID: 35630305 PMCID: PMC9146408 DOI: 10.3390/microorganisms10050859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 02/01/2023] Open
Abstract
Benthic microbial communities of intertidal zones perform important biogeochemical processes and provide accessible nutrients for higher organisms. To unravel the ecosystem services of salt marsh microbial communities, we analyzed bacterial diversity and metabolic potential along the land–sea transition zone on seasonal scales on the German North Sea Island of Spiekeroog. Analysis of bacterial community was based on amplicon sequencing of 16S rRNA genes and –transcripts. Insights into potential community function were obtained by applying the gene prediction tool tax4fun2. We found that spatial variation of community composition was greater than seasonal variations. Alphaproteobacteria (15%), Gammaproteobacteria (17%) and Planctomycetes (11%) were the most abundant phyla across all samples. Differences between the DNA-based resident and RNA-based active communities were most pronounced within the Planctomycetes (17% and 5%) and Cyanobacteriia (3% and 12%). Seasonal differences were seen in higher abundance of Gammaproteobacteria in March 2015 (25%) and a cyanobacterial summer bloom, accounting for up to 70% of the active community. Taxonomy-based prediction of function showed increasing potentials for nitrification, assimilatory nitrate and sulfate reduction from sea to land, while the denitrification and dissimilatory sulfate reduction increased towards the sea. In conclusion, seasonal differences mainly occurred by blooming of individual taxa, while the overall community composition strongly corresponded to locations. Shifts in their metabolism could drive the salt marsh’s function, e.g., as a potential nitrogen sink.
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9
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Rolando JL, Kolton M, Song T, Kostka JE. The core root microbiome of Spartina alterniflora is predominated by sulfur-oxidizing and sulfate-reducing bacteria in Georgia salt marshes, USA. MICROBIOME 2022; 10:37. [PMID: 35227326 PMCID: PMC8886783 DOI: 10.1186/s40168-021-01187-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/25/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Salt marshes are dominated by the smooth cordgrass Spartina alterniflora on the US Atlantic and Gulf of Mexico coastlines. Although soil microorganisms are well known to mediate important biogeochemical cycles in salt marshes, little is known about the role of root microbiomes in supporting the health and productivity of marsh plant hosts. Leveraging in situ gradients in aboveground plant biomass as a natural laboratory, we investigated the relationships between S. alterniflora primary productivity, sediment redox potential, and the physiological ecology of bulk sediment, rhizosphere, and root microbial communities at two Georgia barrier islands over two growing seasons. RESULTS A marked decrease in prokaryotic alpha diversity with high abundance and increased phylogenetic dispersion was found in the S. alterniflora root microbiome. Significantly higher rates of enzymatic organic matter decomposition, as well as the relative abundances of putative sulfur (S)-oxidizing, sulfate-reducing, and nitrifying prokaryotes correlated with plant productivity. Moreover, these functional guilds were overrepresented in the S. alterniflora rhizosphere and root core microbiomes. Core microbiome bacteria from the Candidatus Thiodiazotropha genus, with the metabolic potential to couple S oxidation with C and N fixation, were shown to be highly abundant in the root and rhizosphere of S. alterniflora. CONCLUSIONS The S. alterniflora root microbiome is dominated by highly active and competitive species taking advantage of available carbon substrates in the oxidized root zone. Two microbially mediated mechanisms are proposed to stimulate S. alterniflora primary productivity: (i) enhanced microbial activity replenishes nutrients and terminal electron acceptors in higher biomass stands, and (ii) coupling of chemolithotrophic S oxidation with carbon (C) and nitrogen (N) fixation by root- and rhizosphere-associated prokaryotes detoxifies sulfide in the root zone while potentially transferring fixed C and N to the host plant. Video Abstract.
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Affiliation(s)
- Jose L Rolando
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - Max Kolton
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
- French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion, University of the Negev, Beer Sheva, Israel
| | - Tianze Song
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA
| | - Joel E Kostka
- Georgia Institute of Technology, School of Biological Sciences, Atlanta, GA, 30332, USA.
- Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA, 30332, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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10
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Defining the
Sphagnum
Core Microbiome across the North American Continent Reveals a Central Role for Diazotrophic Methanotrophs in the Nitrogen and Carbon Cycles of Boreal Peatland Ecosystems. mBio 2022. [PMCID: PMC8863050 DOI: 10.1128/mbio.03714-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peat mosses of the genus Sphagnum are ecosystem engineers that frequently predominate over photosynthetic production in boreal peatlands. Sphagnum spp. host diverse microbial communities capable of nitrogen fixation (diazotrophy) and methane oxidation (methanotrophy), thereby potentially supporting plant growth under severely nutrient-limited conditions. Moreover, diazotrophic methanotrophs represent a possible “missing link” between the carbon and nitrogen cycles, but the functional contributions of the Sphagnum-associated microbiome remain in question. A combination of metagenomics, metatranscriptomics, and dual-isotope incorporation assays was applied to investigate Sphagnum microbiome community composition across the North American continent and provide empirical evidence for diazotrophic methanotrophy in Sphagnum-dominated ecosystems. Remarkably consistent prokaryotic communities were detected in over 250 Sphagnum SSU rRNA libraries from peatlands across the United States (5 states, 17 bog/fen sites, 18 Sphagnum species), with 12 genera of the core microbiome comprising 60% of the relative microbial abundance. Additionally, nitrogenase (nifH) and SSU rRNA gene amplicon analysis revealed that nitrogen-fixing populations made up nearly 15% of the prokaryotic communities, predominated by Nostocales cyanobacteria and Rhizobiales methanotrophs. While cyanobacteria comprised the vast majority (>95%) of diazotrophs detected in amplicon and metagenome analyses, obligate methanotrophs of the genus Methyloferula (order Rhizobiales) accounted for one-quarter of transcribed nifH genes. Furthermore, in dual-isotope tracer experiments, members of the Rhizobiales showed substantial incorporation of 13CH4 and 15N2 isotopes into their rRNA. Our study characterizes the core Sphagnum microbiome across large spatial scales and indicates that diazotrophic methanotrophs, here defined as obligate methanotrophs of the rare biosphere (Methyloferula spp. of the Rhizobiales) that also carry out diazotrophy, play a keystone role in coupling of the carbon and nitrogen cycles in nutrient-poor peatlands.
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11
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Cai M, Yin X, Tang X, Zhang C, Zheng Q, Li M. Metatranscriptomics reveals different features of methanogenic archaea among global vegetated coastal ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149848. [PMID: 34464803 DOI: 10.1016/j.scitotenv.2021.149848] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Vegetated coastal ecosystems (VCEs; i.e., mangroves, saltmarshes, and seagrasses) represent important sources of natural methane emission. Despite recent advances in the understanding of novel taxa and pathways associated with methanogenesis in these ecosystems, the key methanogenic players and the contribution of different substrates to methane formation remain elusive. Here, we systematically investigate the community and activity of methanogens using publicly available metatranscriptomes at a global scale together with our in-house metatranscriptomic dataset. Taxonomic profiling reveals that 13 groups of methanogenic archaea were transcribed in the investigated VCEs, and they were predominated by Methanosarcinales. Among these VCEs, methanogens exhibited all the three known methanogenic pathways in some mangrove sediments, where methylotrophic methanogens Methanosarcinales/Methanomassiliicoccales grew on diverse methyl compounds and coexisted with hydrogenotrophic (mainly Methanomicrobiales) and acetoclastic (mainly Methanothrix) methanogens. Contrastingly, the predominant methanogenic pathway in saltmarshes and seagrasses was constrained to methylotrophic methanogenesis. These findings reveal different archaeal methanogens in VCEs and suggest the potentially distinct methanogenesis contributions in these VCEs to the global warming.
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Affiliation(s)
- Mingwei Cai
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China.
| | - Xiuran Yin
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Xiaoyu Tang
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China; School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, China
| | - Cuijing Zhang
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Qingfei Zheng
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China; School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China.
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China.
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12
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Hernández EG, Baraza E, Smit C, Berg MP, Falcão Salles J. Salt Marsh Elevation Drives Root Microbial Composition of the Native Invasive Grass Elytrigia atherica. Microorganisms 2020; 8:microorganisms8101619. [PMID: 33096699 PMCID: PMC7589393 DOI: 10.3390/microorganisms8101619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023] Open
Abstract
Elytrigia atherica is a native invasive plant species whose expansion on salt marshes is attributed to genotypic and phenotypic adaptations to non-ideal environmental conditions, forming two ecotypes. It is unknown how E. atherica–microbiome interactions are contributing to its adaptation. Here we investigated the effect of sea-water flooding frequency and associated soil (a)biotic conditions on plant traits and root-associated microbial community composition and potential functions of two E. atherica ecotypes. We observed higher endomycorrhizal colonization in high-elevation ecotypes (HE, low inundation frequency), whereas low-elevation ecotypes (LE, high inundation frequency) had higher specific leaf area. Similarly, rhizosphere and endosphere bacterial communities grouped according to ecotypes. Soil ammonium content and elevation explained rhizosphere bacterial composition. Around 60% the endosphere amplicon sequence variants (ASVs) were also found in soil and around 30% of the ASVs were ecotype-specific. The endosphere of HE-ecotype harbored more unique sequences than the LE-ecotype, the latter being abundant in halophylic bacterial species. The composition of the endosphere may explain salinity and drought tolerance in relation to the local environmental needs of each ecotype. Overall, these results suggest that E. atherica is flexible in its association with soil bacteria and ecotype-specific dissimilar, which may enhance its competitive strength in salt marshes.
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Affiliation(s)
- Edisa García Hernández
- Microbial Community Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Correspondence: (E.G.H.); (J.F.S.); Tel.: +31-50-3632236 (E.G.H.); +31-50-36-32162 (J.F.S.)
| | - Elena Baraza
- Departamento de Biologia, Universitat de les Illes Balears-INAGEA, 07122 Mallorca, Spain;
| | - Christian Smit
- Community and Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands; (C.S.); (M.P.B.)
| | - Matty P. Berg
- Community and Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands; (C.S.); (M.P.B.)
- Department of Ecological Science, Section Animal Ecology, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Joana Falcão Salles
- Microbial Community Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Correspondence: (E.G.H.); (J.F.S.); Tel.: +31-50-3632236 (E.G.H.); +31-50-36-32162 (J.F.S.)
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