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Lin YT, Xu T, Ip JCH, Sun Y, Fang L, Luan T, Zhang Y, Qian PY, Qiu JW, Qian PY, Qiu JW. Interactions among deep-sea mussels and their epibiotic and endosymbiotic chemoautotrophic bacteria: Insights from multi-omics analysis. Zool Res 2023; 44:106-125. [PMID: 36419378 PMCID: PMC9841196 DOI: 10.24272/j.issn.2095-8137.2022.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Endosymbiosis with Gammaproteobacteria is fundamental for the success of bathymodioline mussels in deep-sea chemosynthesis-based ecosystems. However, the recent discovery of Campylobacteria on the gill surfaces of these mussels suggests that these host-bacterial relationships may be more complex than previously thought. Using the cold-seep mussel ( Gigantidas haimaensis) as a model, we explored this host-bacterial system by assembling the host transcriptome and genomes of its epibiotic Campylobacteria and endosymbiotic Gammaproteobacteria and quantifying their gene and protein expression levels. We found that the epibiont applies a sulfur oxidizing (SOX) multienzyme complex with the acquisition of soxB from Gammaproteobacteria for energy production and switched from a reductive tricarboxylic acid (rTCA) cycle to a Calvin-Benson-Bassham (CBB) cycle for carbon assimilation. The host provides metabolic intermediates, inorganic carbon, and thiosulfate to satisfy the materials and energy requirements of the epibiont, but whether the epibiont benefits the host is unclear. The endosymbiont adopts methane oxidation and the ribulose monophosphate pathway (RuMP) for energy production, providing the major source of energy for itself and the host. The host obtains most of its nutrients, such as lysine, glutamine, valine, isoleucine, leucine, histidine, and folate, from the endosymbiont. In addition, host pattern recognition receptors, including toll-like receptors, peptidoglycan recognition proteins, and C-type lectins, may participate in bacterial infection, maintenance, and population regulation. Overall, this study provides insights into the complex host-bacterial relationships that have enabled mussels and bacteria to thrive in deep-sea chemosynthetic ecosystems.
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Affiliation(s)
- Yi-Tao Lin
- Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China
| | - Ting Xu
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China,Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Jack Chi-Ho Ip
- Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China
| | - Yanan Sun
- Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China
| | - Ling Fang
- Instrumental Analysis & Research Center, Sun Yat-Sen University, Guangzhou, Guangdong 510875, China
| | - Tiangang Luan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong 510875, China,Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Yu Zhang
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong 518060, China,E-mail:
| | - Pei-Yuan Qian
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China,Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong SAR, China,
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, Guangdong 511458, China,
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Sogin EM, Kleiner M, Borowski C, Gruber-Vodicka HR, Dubilier N. Life in the Dark: Phylogenetic and Physiological Diversity of Chemosynthetic Symbioses. Annu Rev Microbiol 2021; 75:695-718. [PMID: 34351792 DOI: 10.1146/annurev-micro-051021-123130] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Possibly the last discovery of a previously unknown major ecosystem on Earth was made just over half a century ago, when researchers found teaming communities of animals flourishing two and a half kilometers below the ocean surface at hydrothermal vents. We now know that these highly productive ecosystems are based on nutritional symbioses between chemosynthetic bacteria and eukaryotes and that these chemosymbioses are ubiquitous in both deep-sea and shallow-water environments. The symbionts are primary producers that gain energy from the oxidation of reduced compounds, such as sulfide and methane, to fix carbon dioxide or methane into biomass to feed their hosts. This review outlines how the symbiotic partners have adapted to living together. We first focus on the phylogenetic and metabolic diversity of these symbioses and then highlight selected research directions that could advance our understanding of the processes that shaped the evolutionary and ecological success of these associations. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- E Maggie Sogin
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany; ,
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27607, USA
| | - Christian Borowski
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany; , .,MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359, Bremen, Germany
| | | | - Nicole Dubilier
- Max Planck Institute for Marine Microbiology, 28359, Bremen, Germany; , .,MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359, Bremen, Germany
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Ip JCH, Xu T, Sun J, Li R, Chen C, Lan Y, Han Z, Zhang H, Wei J, Wang H, Tao J, Cai Z, Qian PY, Qiu JW. Host-Endosymbiont Genome Integration in a Deep-Sea Chemosymbiotic Clam. Mol Biol Evol 2021; 38:502-518. [PMID: 32956455 PMCID: PMC7826175 DOI: 10.1093/molbev/msaa241] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Endosymbiosis with chemosynthetic bacteria has enabled many deep-sea invertebrates to thrive at hydrothermal vents and cold seeps, but most previous studies on this mutualism have focused on the bacteria only. Vesicomyid clams dominate global deep-sea chemosynthesis-based ecosystems. They differ from most deep-sea symbiotic animals in passing their symbionts from parent to offspring, enabling intricate coevolution between the host and the symbiont. Here, we sequenced the genomes of the clam Archivesica marissinica (Bivalvia: Vesicomyidae) and its bacterial symbiont to understand the genomic/metabolic integration behind this symbiosis. At 1.52 Gb, the clam genome encodes 28 genes horizontally transferred from bacteria, a large number of pseudogenes and transposable elements whose massive expansion corresponded to the timing of the rise and subsequent divergence of symbiont-bearing vesicomyids. The genome exhibits gene family expansion in cellular processes that likely facilitate chemoautotrophy, including gas delivery to support energy and carbon production, metabolite exchange with the symbiont, and regulation of the bacteriocyte population. Contraction in cellulase genes is likely adaptive to the shift from phytoplankton-derived to bacteria-based food. It also shows contraction in bacterial recognition gene families, indicative of suppressed immune response to the endosymbiont. The gammaproteobacterium endosymbiont has a reduced genome of 1.03 Mb but retains complete pathways for sulfur oxidation, carbon fixation, and biosynthesis of 20 common amino acids, indicating the host’s high dependence on the symbiont for nutrition. Overall, the host–symbiont genomes show not only tight metabolic complementarity but also distinct signatures of coevolution allowing the vesicomyids to thrive in chemosynthesis-based ecosystems.
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Affiliation(s)
- Jack Chi-Ho Ip
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.,HKBU Institute of Research and Continuing Education, Virtual University Park, Shenzhen, China.,Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ting Xu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.,HKBU Institute of Research and Continuing Education, Virtual University Park, Shenzhen, China.,Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jin Sun
- Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Runsheng Li
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China
| | - Chong Chen
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa Prefecture, Japan
| | - Yi Lan
- Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhuang Han
- Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Science, Sanya, Hainan, China
| | - Haibin Zhang
- Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Science, Sanya, Hainan, China
| | - Jiangong Wei
- MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, China
| | - Hongbin Wang
- MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, China
| | - Jun Tao
- MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong, China
| | - Pei-Yuan Qian
- Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.,HKBU Institute of Research and Continuing Education, Virtual University Park, Shenzhen, China.,Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
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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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Sass K, Güllert S, Streit WR, Perner M. A hydrogen-oxidizing bacterium enriched from the open ocean resembling a symbiont. ENVIRONMENTAL MICROBIOLOGY REPORTS 2020; 12:396-405. [PMID: 32338395 DOI: 10.1111/1758-2229.12847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 03/31/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
A new autotrophic hydrogen-oxidizing Chromatiaceae bacterium, namely bacterium CTD079, was enriched from a water column sample at 1500 m water depth in the southern Pacific Ocean. Based on the phylogeny of 16S rRNA genes, it was closely related to a scaly snail endosymbiont (99.2% DNA sequence identity) whose host so far is only known to colonize hydrothermal vents along the Indian ridge. The average nucleotide identity between the genomes of CTD079 and the snail endosymbiont was 91%. The observed differences likely reflect adaptations to their specific habitats. For example, CTD079 encodes additional enzymes like the formate dehydrogenase increasing the organism's spectrum of energy generation pathways. Other additional physiological features of CTD079 included the increase of viral defence strategies, secretion systems and specific transporters for essential elements. These important genome characteristics suggest an adaptation to life in the open ocean.
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Affiliation(s)
- Katharina Sass
- Molecular Biology of Microbial Consortia, Universität Hamburg, Hamburg, Germany
- Microbiology and Biotechnology, Universität Hamburg, Hamburg, Germany
| | - Simon Güllert
- Microbiology and Biotechnology, Universität Hamburg, Hamburg, Germany
| | - Wolfgang R Streit
- Microbiology and Biotechnology, Universität Hamburg, Hamburg, Germany
| | - Mirjam Perner
- Molecular Biology of Microbial Consortia, Universität Hamburg, Hamburg, Germany
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Russell SL, Pepper-Tunick E, Svedberg J, Byrne A, Ruelas Castillo J, Vollmers C, Beinart RA, Corbett-Detig R. Horizontal transmission and recombination maintain forever young bacterial symbiont genomes. PLoS Genet 2020; 16:e1008935. [PMID: 32841233 PMCID: PMC7473567 DOI: 10.1371/journal.pgen.1008935] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 09/04/2020] [Accepted: 06/16/2020] [Indexed: 12/30/2022] Open
Abstract
Bacterial symbionts bring a wealth of functions to the associations they participate in, but by doing so, they endanger the genes and genomes underlying these abilities. When bacterial symbionts become obligately associated with their hosts, their genomes are thought to decay towards an organelle-like fate due to decreased homologous recombination and inefficient selection. However, numerous associations exist that counter these expectations, especially in marine environments, possibly due to ongoing horizontal gene flow. Despite extensive theoretical treatment, no empirical study thus far has connected these underlying population genetic processes with long-term evolutionary outcomes. By sampling marine chemosynthetic bacterial-bivalve endosymbioses that range from primarily vertical to strictly horizontal transmission, we tested this canonical theory. We found that transmission mode strongly predicts homologous recombination rates, and that exceedingly low recombination rates are associated with moderate genome degradation in the marine symbionts with nearly strict vertical transmission. Nonetheless, even the most degraded marine endosymbiont genomes are occasionally horizontally transmitted and are much larger than their terrestrial insect symbiont counterparts. Therefore, horizontal transmission and recombination enable efficient natural selection to maintain intermediate symbiont genome sizes and substantial functional genetic variation.
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Affiliation(s)
- Shelbi L. Russell
- Department of Molecular Cellular and Developmental Biology. University of California Santa Cruz, Santa Cruz, California, United States of America
- Department of Biomolecular Engineering. University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Evan Pepper-Tunick
- Department of Biomolecular Engineering. University of California Santa Cruz, Santa Cruz, California, United States of America
- Genomics Institute, University of California, Santa Cruz, California, United States of America
| | - Jesper Svedberg
- Department of Biomolecular Engineering. University of California Santa Cruz, Santa Cruz, California, United States of America
- Genomics Institute, University of California, Santa Cruz, California, United States of America
| | - Ashley Byrne
- Department of Molecular Cellular and Developmental Biology. University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Jennie Ruelas Castillo
- Department of Molecular Cellular and Developmental Biology. University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Christopher Vollmers
- Department of Biomolecular Engineering. University of California Santa Cruz, Santa Cruz, California, United States of America
- Genomics Institute, University of California, Santa Cruz, California, United States of America
| | - Roxanne A. Beinart
- Graduate School of Oceanography. University of Rhode Island, Narragansett, Rhode Island, United States of America
| | - Russell Corbett-Detig
- Department of Biomolecular Engineering. University of California Santa Cruz, Santa Cruz, California, United States of America
- Genomics Institute, University of California, Santa Cruz, California, United States of America
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Mizutani Y, Mori T, Miyazaki T, Fukuzaki S, Tanaka R. Microbial community analysis in the gills of abalones suggested possible dominance of epsilonproteobacterium in Haliotis gigantea. PeerJ 2020; 8:e9326. [PMID: 32655989 PMCID: PMC7333650 DOI: 10.7717/peerj.9326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/18/2020] [Indexed: 02/01/2023] Open
Abstract
Gills are important organs for aquatic invertebrates because they harbor chemosynthetic bacteria, which fix inorganic carbon and/or nitrogen and provide their hosts with organic compounds. Nevertheless, in contrast to the intensive researches related to the gut microbiota, much is still needed to further understand the microbiota within the gills of invertebrates. Using abalones as a model, we investigated the community structure of microbes associated with the gills of these invertebrates using next-generation sequencing. Molecular identification of representative bacterial sequences was performed using cloning, nested PCR and fluorescence in situ hybridization (FISH) analysis with specific primers or probes. We examined three abalone species, namely Haliotis gigantea, H. discus and H. diversicolor using seawater and stones as controls. Microbiome analysis suggested that the gills of all three abalones had the unclassified Spirochaetaceae (one OTU, 15.7 ± 0.04%) and Mycoplasma sp. (one OTU, 9.1 ± 0.03%) as the core microbes. In most libraries from the gills of H. gigantea, however, a previously unknown epsilonproteobacterium species (one OTU) was considered as the dominant bacterium, which accounted for 62.2% of the relative abundance. The epsilonproteobacterium was only detected in the gills of H. diversicolor at 0.2% and not in H. discus suggesting that it may be unique to H. gigantea. Phylogenetic analysis performed using a near full-length 16S rRNA gene placed the uncultured epsilonproteobacterium species at the root of the family Helicobacteraceae. Interestingly, the uncultured epsilonproteobacterium was commonly detected from gill tissue rather than from the gut and foot tissues using a nested PCR assay with uncultured epsilonproteobacterium-specific primers. FISH analysis with the uncultured epsilonproteobacterium-specific probe revealed that probe-reactive cells in H. gigantea had a coccus-like morphology and formed microcolonies on gill tissue. This is the first report to show that epsilonproteobacterium has the potential to be a dominant species in the gills of the coastal gastropod, H. gigantea.
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Affiliation(s)
- Yukino Mizutani
- Graduate School of Bioresources, Mie University, Tsu, Mie, Japan
| | - Tetsushi Mori
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Taeko Miyazaki
- Graduate School of Bioresources, Mie University, Tsu, Mie, Japan
| | - Satoshi Fukuzaki
- Graduate School of Bioresources, Mie University, Tsu, Mie, Japan
| | - Reiji Tanaka
- Graduate School of Bioresources, Mie University, Tsu, Mie, Japan
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McCuaig B, Peña-Castillo L, Dufour SC. Metagenomic analysis suggests broad metabolic potential in extracellular symbionts of the bivalve Thyasira cf. gouldi. Anim Microbiome 2020; 2:7. [PMID: 33499960 PMCID: PMC7807488 DOI: 10.1186/s42523-020-00025-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/20/2020] [Indexed: 11/26/2022] Open
Abstract
Background Next-generation sequencing has opened new avenues for studying metabolic capabilities of bacteria that cannot be cultured. Here, we provide a metagenomic description of chemoautotrophic gammaproteobacterial symbionts associated with Thyasira cf. gouldi, a sediment-dwelling bivalve from the family Thyasiridae. Thyasirid symbionts differ from those of other bivalves by being extracellular, and recent work suggests that they are capable of living freely in the environment. Results Thyasira cf. gouldi symbionts appear to form mixed, non-clonal populations in the host, show no signs of genomic reduction and contain many genes that would only be useful outside the host, including flagellar and chemotaxis genes. The thyasirid symbionts may be capable of sulfur oxidation via both the sulfur oxidation and reverse dissimilatory sulfate reduction pathways, as observed in other bivalve symbionts. In addition, genes for hydrogen oxidation and dissimilatory nitrate reduction were found, suggesting varied metabolic capabilities under a range of redox conditions. The genes of the tricarboxylic acid cycle are also present, along with membrane bound sugar importer channels, suggesting that the bacteria may be mixotrophic. Conclusions In this study, we have generated the first thyasirid symbiont genomic resources. In Thyasira cf. gouldi, symbiont populations appear non-clonal and encode genes for a plethora of metabolic capabilities; future work should examine whether symbiont heterogeneity and metabolic breadth, which have been shown in some intracellular chemosymbionts, are signatures of extracellular chemosymbionts in bivalves.
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Affiliation(s)
- Bonita McCuaig
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Lourdes Peña-Castillo
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada.,Department of Computer Science, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Suzanne C Dufour
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada.
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Seah BKB, Antony CP, Huettel B, Zarzycki J, Schada von Borzyskowski L, Erb TJ, Kouris A, Kleiner M, Liebeke M, Dubilier N, Gruber-Vodicka HR. Sulfur-Oxidizing Symbionts without Canonical Genes for Autotrophic CO 2 Fixation. mBio 2019; 10:e01112-19. [PMID: 31239380 PMCID: PMC6593406 DOI: 10.1128/mbio.01112-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/23/2019] [Indexed: 01/25/2023] Open
Abstract
Since the discovery of symbioses between sulfur-oxidizing (thiotrophic) bacteria and invertebrates at hydrothermal vents over 40 years ago, it has been assumed that autotrophic fixation of CO2 by the symbionts drives these nutritional associations. In this study, we investigated "Candidatus Kentron," the clade of symbionts hosted by Kentrophoros, a diverse genus of ciliates which are found in marine coastal sediments around the world. Despite being the main food source for their hosts, Kentron bacteria lack the key canonical genes for any of the known pathways for autotrophic carbon fixation and have a carbon stable isotope fingerprint that is unlike other thiotrophic symbionts from similar habitats. Our genomic and transcriptomic analyses instead found metabolic features consistent with growth on organic carbon, especially organic and amino acids, for which they have abundant uptake transporters. All known thiotrophic symbionts have converged on using reduced sulfur to gain energy lithotrophically, but they are diverse in their carbon sources. Some clades are obligate autotrophs, while many are mixotrophs that can supplement autotrophic carbon fixation with heterotrophic capabilities similar to those in Kentron. Here we show that Kentron bacteria are the only thiotrophic symbionts that appear to be entirely heterotrophic, unlike all other thiotrophic symbionts studied to date, which possess either the Calvin-Benson-Bassham or the reverse tricarboxylic acid cycle for autotrophy.IMPORTANCE Many animals and protists depend on symbiotic sulfur-oxidizing bacteria as their main food source. These bacteria use energy from oxidizing inorganic sulfur compounds to make biomass autotrophically from CO2, serving as primary producers for their hosts. Here we describe a clade of nonautotrophic sulfur-oxidizing symbionts, "Candidatus Kentron," associated with marine ciliates. They lack genes for known autotrophic pathways and have a carbon stable isotope fingerprint heavier than other symbionts from similar habitats. Instead, they have the potential to oxidize sulfur to fuel the uptake of organic compounds for heterotrophic growth, a metabolic mode called chemolithoheterotrophy that is not found in other symbioses. Although several symbionts have heterotrophic features to supplement primary production, in Kentron they appear to supplant it entirely.
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Affiliation(s)
| | | | - Bruno Huettel
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Jan Zarzycki
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Tobias J Erb
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Angela Kouris
- Energy Bioengineering and Geomicrobiology Group, University of Calgary, Calgary, Alberta, Canada
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Manuel Liebeke
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Nicole Dubilier
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
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Chemosynthetic symbiont with a drastically reduced genome serves as primary energy storage in the marine flatworm Paracatenula. Proc Natl Acad Sci U S A 2019; 116:8505-8514. [PMID: 30962361 PMCID: PMC6486704 DOI: 10.1073/pnas.1818995116] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Animals typically store their primary energy reserves in specialized cells. Here, we show that in the small marine flatworm Paracatenula, this function is performed by its bacterial chemosynthetic symbiont. The intracellular symbiont occupies half of the biomass in the symbiosis and has a highly reduced genome but efficiently stocks up and maintains carbon and energy, particularly sugars. The host rarely digests the symbiont cells to access these stocks. Instead, the symbionts appear to provide the bulk nutrition by secreting outer-membrane vesicles. This is in contrast to all other described chemosynthetic symbioses, where the hosts continuously digest full cells of a small and ideally growing symbiont population that cannot provide a long-term buffering capacity during nutrient limitation. Hosts of chemoautotrophic bacteria typically have much higher biomass than their symbionts and consume symbiont cells for nutrition. In contrast to this, chemoautotrophic Candidatus Riegeria symbionts in mouthless Paracatenula flatworms comprise up to half of the biomass of the consortium. Each species of Paracatenula harbors a specific Ca. Riegeria, and the endosymbionts have been vertically transmitted for at least 500 million years. Such prolonged strict vertical transmission leads to streamlining of symbiont genomes, and the retained physiological capacities reveal the functions the symbionts provide to their hosts. Here, we studied a species of Paracatenula from Sant’Andrea, Elba, Italy, using genomics, gene expression, imaging analyses, as well as targeted and untargeted MS. We show that its symbiont, Ca. R. santandreae has a drastically smaller genome (1.34 Mb) than the symbiont´s free-living relatives (4.29–4.97 Mb) but retains a versatile and energy-efficient metabolism. It encodes and expresses a complete intermediary carbon metabolism and enhanced carbon fixation through anaplerosis and accumulates massive intracellular inclusions such as sulfur, polyhydroxyalkanoates, and carbohydrates. Compared with symbiotic and free-living chemoautotrophs, Ca. R. santandreae’s versatility in energy storage is unparalleled in chemoautotrophs with such compact genomes. Transmission EM as well as host and symbiont expression data suggest that Ca. R. santandreae largely provisions its host via outer-membrane vesicle secretion. With its high share of biomass in the symbiosis and large standing stocks of carbon and energy reserves, it has a unique role for bacterial symbionts—serving as the primary energy storage for its animal host.
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11
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Raina JB, Fernandez V, Lambert B, Stocker R, Seymour JR. The role of microbial motility and chemotaxis in symbiosis. Nat Rev Microbiol 2019; 17:284-294. [DOI: 10.1038/s41579-019-0182-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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12
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Russell SL. Transmission mode is associated with environment type and taxa across bacteria-eukaryote symbioses: a systematic review and meta-analysis. FEMS Microbiol Lett 2019; 366:5289862. [DOI: 10.1093/femsle/fnz013] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 01/15/2019] [Indexed: 12/22/2022] Open
Affiliation(s)
- Shelbi L Russell
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95060; USA
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13
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Taxonomic and functional heterogeneity of the gill microbiome in a symbiotic coastal mangrove lucinid species. ISME JOURNAL 2018; 13:902-920. [PMID: 30518817 PMCID: PMC6461927 DOI: 10.1038/s41396-018-0318-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 10/23/2018] [Accepted: 11/04/2018] [Indexed: 12/28/2022]
Abstract
Lucinidae clams harbor gammaproteobacterial thioautotrophic gill endosymbionts that are environmentally acquired. Thioautotrophic lucinid symbionts are related to metabolically similar symbionts associated with diverse marine host taxa and fall into three distinct phylogenetic clades. Most studies on the lucinid–bacteria chemosymbiosis have been done with seagrass-dwelling hosts, whose symbionts belong to the largest phylogenetic clade. In this study, we examined the taxonomy and functional repertoire of bacterial endosymbionts at an unprecedented resolution from Phacoides pectinatus retrieved from mangrove-lined coastal sediments, which are underrepresented in chemosymbiosis studies. The P. pectinatus thioautotrophic endosymbiont expressed metabolic gene variants for thioautotrophy, respiration, and nitrogen assimilation distinct from previously characterized lucinid thioautotrophic symbionts and other marine symbionts. At least two other bacterial species with different metabolisms were also consistently identified in the P. pectinatus gill microbiome, including a Kistimonas-like species and a Spirochaeta-like species. Bacterial transcripts involved in adhesion, growth, and virulence and mixotrophy were highly expressed, as were host-related hemoglobin and lysozyme transcripts indicative of sulfide/oxygen/CO2 transport and bactericidal activity. This study suggests the potential roles of P. pectinatus and its gill microbiome species in mangrove sediment biogeochemistry and offers insights into host and microbe metabolisms in the habitat.
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Scott KM, Williams J, Porter CMB, Russel S, Harmer TL, Paul JH, Antonen KM, Bridges MK, Camper GJ, Campla CK, Casella LG, Chase E, Conrad JW, Cruz MC, Dunlap DS, Duran L, Fahsbender EM, Goldsmith DB, Keeley RF, Kondoff MR, Kussy BI, Lane MK, Lawler S, Leigh BA, Lewis C, Lostal LM, Marking D, Mancera PA, McClenthan EC, McIntyre EA, Mine JA, Modi S, Moore BD, Morgan WA, Nelson KM, Nguyen KN, Ogburn N, Parrino DG, Pedapudi AD, Pelham RP, Preece AM, Rampersad EA, Richardson JC, Rodgers CM, Schaffer BL, Sheridan NE, Solone MR, Staley ZR, Tabuchi M, Waide RJ, Wanjugi PW, Young S, Clum A, Daum C, Huntemann M, Ivanova N, Kyrpides N, Mikhailova N, Palaniappan K, Pillay M, Reddy TBK, Shapiro N, Stamatis D, Varghese N, Woyke T, Boden R, Freyermuth SK, Kerfeld CA. Genomes of ubiquitous marine and hypersaline Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira spp. encode a diversity of mechanisms to sustain chemolithoautotrophy in heterogeneous environments. Environ Microbiol 2018. [PMID: 29521452 DOI: 10.1111/1462-2920.14090] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemolithoautotrophic bacteria from the genera Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira are common, sometimes dominant, isolates from sulfidic habitats including hydrothermal vents, soda and salt lakes and marine sediments. Their genome sequences confirm their membership in a deeply branching clade of the Gammaproteobacteria. Several adaptations to heterogeneous habitats are apparent. Their genomes include large numbers of genes for sensing and responding to their environment (EAL- and GGDEF-domain proteins and methyl-accepting chemotaxis proteins) despite their small sizes (2.1-3.1 Mbp). An array of sulfur-oxidizing complexes are encoded, likely to facilitate these organisms' use of multiple forms of reduced sulfur as electron donors. Hydrogenase genes are present in some taxa, including group 1d and 2b hydrogenases in Hydrogenovibrio marinus and H. thermophilus MA2-6, acquired via horizontal gene transfer. In addition to high-affinity cbb3 cytochrome c oxidase, some also encode cytochrome bd-type quinol oxidase or ba3 -type cytochrome c oxidase, which could facilitate growth under different oxygen tensions, or maintain redox balance. Carboxysome operons are present in most, with genes downstream encoding transporters from four evolutionarily distinct families, which may act with the carboxysomes to form CO2 concentrating mechanisms. These adaptations to habitat variability likely contribute to the cosmopolitan distribution of these organisms.
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Affiliation(s)
- Kathleen M Scott
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - John Williams
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Cody M B Porter
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Sydney Russel
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Tara L Harmer
- Biology Program, Stockton University, Galloway, NJ, USA
| | - John H Paul
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Kirsten M Antonen
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Megan K Bridges
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Gary J Camper
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Christie K Campla
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Leila G Casella
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Eva Chase
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - James W Conrad
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Mercedez C Cruz
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Darren S Dunlap
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Laura Duran
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Elizabeth M Fahsbender
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Dawn B Goldsmith
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Ryan F Keeley
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Matthew R Kondoff
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Breanna I Kussy
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Marannda K Lane
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Stephanie Lawler
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Brittany A Leigh
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Courtney Lewis
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Lygia M Lostal
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Devon Marking
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Paola A Mancera
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Evan C McClenthan
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Emily A McIntyre
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Jessica A Mine
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Swapnil Modi
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Brittney D Moore
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - William A Morgan
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Kaleigh M Nelson
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Kimmy N Nguyen
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Nicholas Ogburn
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - David G Parrino
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Anangamanjari D Pedapudi
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Rebecca P Pelham
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Amanda M Preece
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Elizabeth A Rampersad
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Jason C Richardson
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Christina M Rodgers
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Brent L Schaffer
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Nancy E Sheridan
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Michael R Solone
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Zachery R Staley
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Maki Tabuchi
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Ramond J Waide
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Pauline W Wanjugi
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Suzanne Young
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA
| | - Alicia Clum
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Chris Daum
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Marcel Huntemann
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Natalia Ivanova
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Nikos Kyrpides
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | | | | | - Manoj Pillay
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - T B K Reddy
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Nicole Shapiro
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | | | - Neha Varghese
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Rich Boden
- School of Biological & Marine Sciences, University of Plymouth, Drake Circus, Plymouth, UK.,Sustainable Earth Institute, University of Plymouth, Drake Circus, Plymouth, UK
| | | | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.,MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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15
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Russell SL, Cavanaugh CM. Intrahost Genetic Diversity of Bacterial Symbionts Exhibits Evidence of Mixed Infections and Recombinant Haplotypes. Mol Biol Evol 2017; 34:2747-2761. [DOI: 10.1093/molbev/msx188] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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16
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Mixed transmission modes and dynamic genome evolution in an obligate animal-bacterial symbiosis. ISME JOURNAL 2017; 11:1359-1371. [PMID: 28234348 DOI: 10.1038/ismej.2017.10] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/22/2016] [Accepted: 01/09/2017] [Indexed: 11/08/2022]
Abstract
Reliable transmission of symbionts between host generations facilitates the evolution of beneficial and pathogenic associations. Although transmission mode is typically characterized as either vertical or horizontal, the prevalence of intermediate transmission modes, and their impact on symbiont genome evolution, are understudied. Here, we use population genomics to explore mixed transmission modes of chemosynthetic bacterial symbionts in the bivalve Solemya velum. Despite strong evidence for symbiont inheritance through host oocytes, whole-genome analyses revealed signatures of frequent horizontal transmission, including discordant mitochondrial-symbiont genealogies, widespread recombination and a dynamic symbiont genome structure consistent with evolutionary patterns of horizontally transmitted associations. Population-level analyses thus provide a tractable means of ascertaining the fidelity of vertical versus horizontal transmission. Our data support the strong influence horizontal transmission can have on symbiont genome evolution, and shed light on the dynamic evolutionary pressures shaping symbiotic bacterial genomes.
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17
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Marine genomics: News and views. Mar Genomics 2017; 31:1-8. [DOI: 10.1016/j.margen.2016.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 11/23/2022]
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18
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Ikuta T, Igawa K, Tame A, Kuroiwa T, Kuroiwa H, Aoki Y, Takaki Y, Nagai Y, Ozawa G, Yamamoto M, Deguchi R, Fujikura K, Maruyama T, Yoshida T. Surfing the vegetal pole in a small population: extracellular vertical transmission of an 'intracellular' deep-sea clam symbiont. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160130. [PMID: 27293794 PMCID: PMC4892456 DOI: 10.1098/rsos.160130] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/21/2016] [Indexed: 06/06/2023]
Abstract
Symbiont transmission is a key event for understanding the processes underlying symbiotic associations and their evolution. However, our understanding of the mechanisms of symbiont transmission remains still fragmentary. The deep-sea clam Calyptogena okutanii harbours obligate sulfur-oxidizing intracellular symbiotic bacteria in the gill epithelial cells. In this study, we determined the localization of their symbiont associating with the spawned eggs, and the population size of the symbiont transmitted via the eggs. We show that the symbionts are located on the outer surface of the egg plasma membrane at the vegetal pole, and that each egg carries approximately 400 symbiont cells, each of which contains close to 10 genomic copies. The very small population size of the symbiont transmitted via the eggs might narrow the bottleneck and increase genetic drift, while polyploidy and its transient extracellular lifestyle might slow the rate of genome reduction. Additionally, the extracellular localization of the symbiont on the egg surface may increase the chance of symbiont exchange. This new type of extracellular transovarial transmission provides insights into complex interactions between the host and symbiont, development of both host and symbiont, as well as the population dynamics underlying genetic drift and genome evolution in microorganisms.
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Affiliation(s)
- Tetsuro Ikuta
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Kanae Igawa
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
| | - Akihiro Tame
- Marine Works Japan, Ltd, 3-54-1 Oppamahigashi, Yokosuka, Kanagawa 237-0063, Japan
| | - Tsuneyoshi Kuroiwa
- Department of Chemical and Biological Sciences, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Haruko Kuroiwa
- Department of Chemical and Biological Sciences, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Yui Aoki
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Yoshihiro Takaki
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Yukiko Nagai
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Genki Ozawa
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
- Department of Marine Biosciences, School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Masahiro Yamamoto
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Ryusaku Deguchi
- Department of Biology, Miyagi University of Education, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - Katsunori Fujikura
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Tadashi Maruyama
- Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
| | - Takao Yoshida
- Department of Marine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
- Department of Marine Biosciences, School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
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Sayavedra L, Kleiner M, Ponnudurai R, Wetzel S, Pelletier E, Barbe V, Satoh N, Shoguchi E, Fink D, Breusing C, Reusch TBH, Rosenstiel P, Schilhabel MB, Becher D, Schweder T, Markert S, Dubilier N, Petersen JM. Abundant toxin-related genes in the genomes of beneficial symbionts from deep-sea hydrothermal vent mussels. eLife 2015; 4:e07966. [PMID: 26371554 PMCID: PMC4612132 DOI: 10.7554/elife.07966] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 09/14/2015] [Indexed: 01/06/2023] Open
Abstract
Bathymodiolus mussels live in symbiosis with intracellular sulfur-oxidizing (SOX) bacteria that provide them with nutrition. We sequenced the SOX symbiont genomes from two Bathymodiolus species. Comparison of these symbiont genomes with those of their closest relatives revealed that the symbionts have undergone genome rearrangements, and up to 35% of their genes may have been acquired by horizontal gene transfer. Many of the genes specific to the symbionts were homologs of virulence genes. We discovered an abundant and diverse array of genes similar to insecticidal toxins of nematode and aphid symbionts, and toxins of pathogens such as Yersinia and Vibrio. Transcriptomics and proteomics revealed that the SOX symbionts express the toxin-related genes (TRGs) in their hosts. We hypothesize that the symbionts use these TRGs in beneficial interactions with their host, including protection against parasites. This would explain why a mutualistic symbiont would contain such a remarkable 'arsenal' of TRGs.
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Affiliation(s)
| | - Manuel Kleiner
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Ruby Ponnudurai
- Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Silke Wetzel
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Eric Pelletier
- Genoscope - Centre National de Séquençage, Commissariat à l'énergie atomique et aux énergies alternatives, Evry, France
- Metabolic Genomics Group, Commissariat à l'énergie atomique et aux énergies alternatives, Evry, France
- University of Évry-Val d'Essonne, Evry, France
| | - Valerie Barbe
- Genoscope - Centre National de Séquençage, Commissariat à l'énergie atomique et aux énergies alternatives, Evry, France
| | - Nori Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Dennis Fink
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Corinna Breusing
- Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Thorsten BH Reusch
- Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | | | | | - Dörte Becher
- Institute of Marine Biotechnology, Greifswald, Germany
- Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Thomas Schweder
- Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Stephanie Markert
- Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Nicole Dubilier
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- University of Bremen, Bremen, Germany
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