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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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Ratinskaia L, Malavin S, Zvi-Kedem T, Vintila S, Kleiner M, Rubin-Blum M. Metabolically-versatile Ca. Thiodiazotropha symbionts of the deep-sea lucinid clam Lucinoma kazani have the genetic potential to fix nitrogen. ISME COMMUNICATIONS 2024; 4:ycae076. [PMID: 38873029 PMCID: PMC11171427 DOI: 10.1093/ismeco/ycae076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/06/2024] [Accepted: 05/31/2024] [Indexed: 06/15/2024]
Abstract
Lucinid clams are one of the most diverse and widespread symbiont-bearing animal groups in both shallow and deep-sea chemosynthetic habitats. Lucinids harbor Ca. Thiodiazotropha symbionts that can oxidize inorganic and organic substrates such as hydrogen sulfide and formate to gain energy. The interplay between these key metabolic functions, nutrient uptake and biotic interactions in Ca. Thiodiazotropha is not fully understood. We collected Lucinoma kazani individuals from next to a deep-sea brine pool in the eastern Mediterranean Sea, at a depth of 1150 m and used Oxford Nanopore and Illumina sequencing to obtain high-quality genomes of their Ca. Thiodiazotropha gloverae symbiont. The genomes served as the basis for transcriptomic and proteomic analyses to characterize the in situ gene expression, metabolism and physiology of the symbionts. We found genes needed for N2 fixation in the deep-sea symbiont's genome, which, to date, were only found in shallow-water Ca. Thiodiazotropha. However, we did not detect the expression of these genes and thus the potential role of nitrogen fixation in this symbiosis remains to be determined. We also found the high expression of carbon fixation and sulfur oxidation genes, which indicate chemolithoautotrophy as the key physiology of Ca. Thiodiazotropha. However, we also detected the expression of pathways for using methanol and formate as energy sources. Our findings highlight the key traits these microbes maintain to support the nutrition of their hosts and interact with them.
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Affiliation(s)
- Lina Ratinskaia
- Biology Department, National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa 3108000Israel
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 3498838Israel
| | - Stas Malavin
- Biology Department, National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa 3108000Israel
- Department of Environmental Hydrology and Microbiology, Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker 8499000, Israel
| | - Tal Zvi-Kedem
- Biology Department, National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa 3108000Israel
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 3498838Israel
| | - Simina Vintila
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, United States
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, United States
| | - Maxim Rubin-Blum
- Biology Department, National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa 3108000Israel
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 3498838Israel
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Chemoautotrophy, symbiosis and sedimented diatoms support high biomass of benthic molluscs in the Namibian shelf. Sci Rep 2022; 12:9731. [PMID: 35697901 PMCID: PMC9192762 DOI: 10.1038/s41598-022-13571-w] [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: 12/13/2021] [Accepted: 05/17/2022] [Indexed: 11/26/2022] Open
Abstract
The molluscs Lucinoma capensis, Lembulus bicuspidatus and Nassarius vinctus are highly abundant in Namibian oxygen minimum zone sediments. To understand which nutritional strategies allow them to reach such impressive abundances in this extreme habitat we investigated their trophic diversity, including a chemosymbiosis in L. capensis, focussing on nitrogen biochemical pathways of the symbionts. We combined results of bulk nitrogen and carbon (δ13C and δ15N) and of compound-specific isotope analyses of amino acid nitrogen (AAs—δ15NPhe and δ15NGlu), with 16S rRNA gene sequencing of L. capensis tissues and also with exploratory results of ammonium, nitrate and nitrite turnover. The trophic position (TP) of the bivalve L. capensis is placed between autotrophy and mixotrophy, consistent with its proposed symbiosis with sulfur-oxidizing Candidatus Thiodiazotropha sp. symbionts. The symbionts are here revealed to perform nitrate reduction and ammonium uptake, with clear indications of ammonium host-symbionts recycling, but surprisingly unable to fix nitrogen. The TP of the bivalve L. bicuspidatus is placed in between mixotrophy and herbivory. The TP of the gastropod N. vinctus reflected omnivory. Multiple lines of evidences in combination with current ecosystem knowledge point to sedimented diatoms as important components of L. bicuspidatus and N. vinctus’ diet, likely supplemented at times with chemoautotrophic bacteria. This study highlights the importance of benthic-pelagic coupling that fosters the dietary base for macrozoobenthos in the OMZ. It further unveils that, in contrast to all shallow water lucinid symbionts, deeper water lucinid symbionts rely on ammonium assimilation rather than dinitrogen fixation to obtain nitrogen for growth.
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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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Osvatic JT, Wilkins LGE, Leibrecht L, Leray M, Zauner S, Polzin J, Camacho Y, Gros O, van Gils JA, Eisen JA, Petersen JM, Yuen B. Global biogeography of chemosynthetic symbionts reveals both localized and globally distributed symbiont groups. Proc Natl Acad Sci U S A 2021; 118:e2104378118. [PMID: 34272286 PMCID: PMC8307296 DOI: 10.1073/pnas.2104378118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the ocean, most hosts acquire their symbionts from the environment. Due to the immense spatial scales involved, our understanding of the biogeography of hosts and symbionts in marine systems is patchy, although this knowledge is essential for understanding fundamental aspects of symbiosis such as host-symbiont specificity and evolution. Lucinidae is the most species-rich and widely distributed family of marine bivalves hosting autotrophic bacterial endosymbionts. Previous molecular surveys identified location-specific symbiont types that "promiscuously" form associations with multiple divergent cooccurring host species. This flexibility of host-microbe pairings is thought to underpin their global success, as it allows hosts to form associations with locally adapted symbionts. We used metagenomics to investigate the biodiversity, functional variability, and genetic exchange among the endosymbionts of 12 lucinid host species from across the globe. We report a cosmopolitan symbiont species, Candidatus Thiodiazotropha taylori, associated with multiple lucinid host species. Ca. T. taylori has achieved more success at dispersal and establishing symbioses with lucinids than any other symbiont described thus far. This discovery challenges our understanding of symbiont dispersal and location-specific colonization and suggests both symbiont and host flexibility underpin the ecological and evolutionary success of the lucinid symbiosis.
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Affiliation(s)
- Jay T Osvatic
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - Laetitia G E Wilkins
- Genome and Biomedical Sciences Facility, Genome Center, University of California, Davis, CA 95616
- Department of Symbiosis, Max Planck Institute for Marine Microbiology, 28209 Bremen, Germany
| | - Lukas Leibrecht
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - Matthieu Leray
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama
| | - Sarah Zauner
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - Julia Polzin
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - Yolanda Camacho
- Centro de Investigación en Ciencias del Mar y Limnología, Escuela de Biología, Universidad de Costa Rica, San Pedro 11501-2060, Costa Rica
| | - Olivier Gros
- UMR 7205, Institut de Systématique, Évolution, Biodiversité, Equipe Biologie de la Mangrove, Département de Biologie, Université des Antilles, 97159 Pointe-à-Pitre Cedex, Guadeloupe
| | - Jan A van Gils
- Royal Netherlands Institute for Sea Research,1790 AB Den Burg, The Netherlands
| | - Jonathan A Eisen
- Genome and Biomedical Sciences Facility, Genome Center, University of California, Davis, CA 95616
- Department of Evolution and Ecology, University of California, Davis, CA 95616
- Department of Medical Microbiology and Immunology, University of California, Davis, CA 95616
| | - Jillian M Petersen
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria;
| | - Benedict Yuen
- Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria;
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Lim SJ, Davis B, Gill D, Swetenburg J, Anderson LC, Engel AS, Campbell BJ. Gill microbiome structure and function in the chemosymbiotic coastal lucinid Stewartia floridana. FEMS Microbiol Ecol 2021; 97:6168404. [PMID: 33705534 DOI: 10.1093/femsec/fiab042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/09/2021] [Indexed: 11/14/2022] Open
Abstract
Lucinid bivalves harbor environmentally acquired, chemosynthetic, gammaproteobacterial gill endosymbionts. Lucinid gill microbiomes, which may contain other gammaproteobacterial and/or spirochete taxa, remain under-sampled. To understand inter-host variability of the lucinid gill microbiome, specifically in the bacterial communities, we analyzed the microbiome content of Stewartia floridana collected from Florida. Sampled gills contained a monospecific gammaproteobacterial endosymbiont expressing lithoautotrophic, mixotrophic, diazotrophic and C1 compound oxidation-related functions previously characterized in similar lucinid species. Another low-abundance Spirochaeta-like species in ∼72% of the sampled gills was most closely related to Spirochaeta-like species in another lucinid Phacoides pectinatus and formed a clade with known marine Spirochaeta symbionts. The spirochete expressed genes were involved in heterotrophy and the transport of sugars, amino acids, peptides and other substrates. Few muscular and neurofilament genes from the host and none from the gammaproteobacterial and spirochete symbionts were differentially expressed among quadrats predominantly covered with seagrass species or 80% bare sand. Our results suggest that spirochetes are facultatively associated with S. floridana, with potential scavenging and nutrient cycling roles. Expressed stress- and defense-related functions in the host and symbionts also suggest species-species communications, which highlight the need for further study of the interactions among lucinid hosts, their microbiomes and their environment.
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Affiliation(s)
- Shen Jean Lim
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Brenton Davis
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Danielle Gill
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - John Swetenburg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Laurie C Anderson
- Department of Geology and Geological Engineering, South Dakota School of Mines & Technology, Rapid City, SD 57701, USA
| | - Annette Summers Engel
- Department of Earth and Planetary Sciences, University of Tennessee Knoxville, Knoxville, TN 37920, USA
| | - Barbara J Campbell
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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Petersen JM, Yuen B. The symbiotic 'all-rounders': Partnerships between marine animals and chemosynthetic nitrogen-fixing bacteria. Appl Environ Microbiol 2021; 87:AEM.02129-20. [PMID: 33355107 PMCID: PMC8090883 DOI: 10.1128/aem.02129-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitrogen fixation is a widespread metabolic trait in certain types of microorganisms called diazotrophs. Bioavailable nitrogen is limited in various habitats on land and in the sea, and accordingly, a range of plant, animal, and single-celled eukaryotes have evolved symbioses with diverse diazotrophic bacteria, with enormous economic and ecological benefits. Until recently, all known nitrogen-fixing symbionts were heterotrophs such as nodulating rhizobia, or photoautotrophs such as cyanobacteria. In 2016, the first chemoautotrophic nitrogen-fixing symbionts were discovered in a common family of marine clams, the Lucinidae. Chemosynthetic nitrogen-fixing symbionts use the chemical energy stored in reduced sulfur compounds to power carbon and nitrogen fixation, making them metabolic 'all-rounders' with multiple functions in the symbiosis. This distinguishes them from heterotrophic symbionts that require a source of carbon from their host, and their chemosynthetic metabolism distinguishes them from photoautotrophic symbionts that produce oxygen, a potent inhibitor of nitrogenase. In this review, we consider evolutionary aspects of this discovery, by comparing strategies that have evolved for hosting intracellular nitrogen-fixing symbionts in plants and animals. The symbiosis between lucinid clams and chemosynthetic nitrogen-fixing bacteria also has important ecological impacts, as they form a nested symbiosis with endangered marine seagrasses. Notably, nitrogen fixation by lucinid symbionts may help support seagrass health by providing a source of nitrogen in seagrass habitats. These discoveries were enabled by new techniques for understanding the activity of microbial populations in natural environments. However, an animal (or plant) host represents a diverse landscape of microbial niches due to its structural, chemical, immune and behavioural properties. In future, methods that resolve microbial activity at the single cell level will provide radical new insights into the regulation of nitrogen fixation in chemosynthetic symbionts, shedding new light on the evolution of nitrogen-fixing symbioses in contrasting hosts and environments.
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Affiliation(s)
- Jillian M Petersen
- Centre for Microbiology and Environmental Systems Science, University of Vienna
| | - Benedict Yuen
- Centre for Microbiology and Environmental Systems Science, University of Vienna
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Cutting out the middle clam: lucinid endosymbiotic bacteria are also associated with seagrass roots worldwide. ISME JOURNAL 2020; 14:2901-2905. [PMID: 32929207 DOI: 10.1038/s41396-020-00771-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 08/18/2020] [Accepted: 09/02/2020] [Indexed: 11/09/2022]
Abstract
Seagrasses and lucinid bivalves inhabit highly reduced sediments with elevated sulphide concentrations. Lucinids house symbiotic bacteria (Ca. Thiodiazotropha) capable of oxidising sediment sulphide, and their presence in sediments has been proposed to promote seagrass growth by decreasing otherwise phytotoxic sulphide levels. However, vast and productive seagrass meadows are present in ecosystems where lucinids do not occur. Hence, we hypothesised that seagrasses themselves host these sulphur-oxidising Ca. Thiodiazotropha that could aid their survival when lucinids are absent. We analysed newly generated and publicly available 16S rRNA gene sequences from seagrass roots and sediments across 14 seagrass species and 10 countries and found that persistent and colonising seagrasses across the world harbour sulphur-oxidising Ca. Thiodiazotropha, regardless of the presence of lucinids. We used fluorescence in situ hybridisation to visually confirm the presence of Ca. Thiodiazotropha on roots of Halophila ovalis, a colonising seagrass species with wide geographical, water depth range, and sedimentary sulphide concentrations. We provide the first evidence that Ca. Thiodiazotropha are commonly present on seagrass roots, providing another mechanism for seagrasses to alleviate sulphide stress globally.
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