1
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Dougan KE, Bellantuono AJ, Kahlke T, Abbriano RM, Chen Y, Shah S, Granados-Cifuentes C, van Oppen MJH, Bhattacharya D, Suggett DJ, Rodriguez-Lanetty M, Chan CX. Whole-genome duplication in an algal symbiont bolsters coral heat tolerance. SCIENCE ADVANCES 2024; 10:eadn2218. [PMID: 39028812 PMCID: PMC11259175 DOI: 10.1126/sciadv.adn2218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 06/14/2024] [Indexed: 07/21/2024]
Abstract
The algal endosymbiont Durusdinium trenchii enhances the resilience of coral reefs under thermal stress. D. trenchii can live freely or in endosymbiosis, and the analysis of genetic markers suggests that this species has undergone whole-genome duplication (WGD). However, the evolutionary mechanisms that underpin the thermotolerance of this species are largely unknown. Here, we present genome assemblies for two D. trenchii isolates, confirm WGD in these taxa, and examine how selection has shaped the duplicated genome regions using gene expression data. We assess how the free-living versus endosymbiotic lifestyles have contributed to the retention and divergence of duplicated genes, and how these processes have enhanced the thermotolerance of D. trenchii. Our combined results suggest that lifestyle is the driver of post-WGD evolution in D. trenchii, with the free-living phase being the most important, followed by endosymbiosis. Adaptations to both lifestyles likely enabled D. trenchii to provide enhanced thermal stress protection to the host coral.
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Affiliation(s)
- Katherine E. Dougan
- School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
- Department of Biological Sciences, Biomolecular Science Institute, Florida International University, Miami, FL 33099, USA
| | - Anthony J. Bellantuono
- Department of Biological Sciences, Biomolecular Science Institute, Florida International University, Miami, FL 33099, USA
| | - Tim Kahlke
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Raffaela M. Abbriano
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Yibi Chen
- School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sarah Shah
- School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Camila Granados-Cifuentes
- Department of Biological Sciences, Biomolecular Science Institute, Florida International University, Miami, FL 33099, USA
| | - Madeleine J. H. van Oppen
- School of Biosciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA
| | - David J. Suggett
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW 2007, Australia
- KAUST Reefscape Restoration Initiative (KRRI) and Red Sea Research Center (RSRC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Mauricio Rodriguez-Lanetty
- Department of Biological Sciences, Biomolecular Science Institute, Florida International University, Miami, FL 33099, USA
| | - Cheong Xin Chan
- School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
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2
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Tran C, Rosenfield GR, Cleves PA, Krediet CJ, Paul MR, Clowez S, Grossman AR, Pringle JR. Photosynthesis and other factors affecting the establishment and maintenance of cnidarian-dinoflagellate symbiosis. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230079. [PMID: 38497261 PMCID: PMC10945401 DOI: 10.1098/rstb.2023.0079] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 02/07/2024] [Indexed: 03/19/2024] Open
Abstract
Coral growth depends on the partnership between the animal hosts and their intracellular, photosynthetic dinoflagellate symbionts. In this study, we used the sea anemone Aiptasia, a laboratory model for coral biology, to investigate the poorly understood mechanisms that mediate symbiosis establishment and maintenance. We found that initial colonization of both adult polyps and larvae by a compatible algal strain was more effective when the algae were able to photosynthesize and that the long-term maintenance of the symbiosis also depended on photosynthesis. In the dark, algal cells were taken up into host gastrodermal cells and not rapidly expelled, but they seemed unable to reproduce and thus were gradually lost. When we used confocal microscopy to examine the interaction of larvae with two algal strains that cannot establish stable symbioses with Aiptasia, it appeared that both pre- and post-phagocytosis mechanisms were involved. With one strain, algae entered the gastric cavity but appeared to be completely excluded from the gastrodermal cells. With the other strain, small numbers of algae entered the gastrodermal cells but appeared unable to proliferate there and were slowly lost upon further incubation. We also asked if the exclusion of either incompatible strain could result simply from their cells' being too large for the host cells to accommodate. However, the size distributions of the compatible and incompatible strains overlapped extensively. Moreover, examination of macerates confirmed earlier reports that individual gastrodermal cells could expand to accommodate multiple algal cells. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- Cawa Tran
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
- Department of Biology, University of San Diego, San Diego, CA 92110, USA
| | - Gabriel R. Rosenfield
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
| | - Phillip A. Cleves
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
| | - Cory J. Krediet
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
| | - Maitri R. Paul
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
| | - Sophie Clowez
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Arthur R. Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - John R. Pringle
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305, USA
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3
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Wang C, Zheng X, Kvitt H, Sheng H, Sun D, Niu G, Tchernov D, Shi T. Lineage-specific symbionts mediate differential coral responses to thermal stress. MICROBIOME 2023; 11:211. [PMID: 37752514 PMCID: PMC10521517 DOI: 10.1186/s40168-023-01653-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 08/23/2023] [Indexed: 09/28/2023]
Abstract
BACKGROUND Ocean warming is a leading cause of increasing episodes of coral bleaching, the dissociation between coral hosts and their dinoflagellate algal symbionts in the family Symbiodiniaceae. While the diversity and flexibility of Symbiodiniaceae is presumably responsible for variations in coral response to physical stressors such as elevated temperature, there is little data directly comparing physiological performance that accounts for symbiont identity associated with the same coral host species. Here, using Pocillopora damicornis harboring genotypically distinct Symbiodiniaceae strains, we examined the physiological responses of the coral holobiont and the dynamics of symbiont community change under thermal stress in a laboratory-controlled experiment. RESULTS We found that P. damicornis dominated with symbionts of metahaplotype D1-D4-D6 in the genus Durusdinium (i.e., PdD holobiont) was more robust to thermal stress than its counterpart with symbionts of metahaplotype C42-C1-C1b-C1c in the genus Cladocopium (i.e., PdC holobiont). Under ambient temperature, however, the thermally sensitive Cladocopium spp. exhibited higher photosynthetic efficiency and translocated more fixed carbon to the host, likely facilitating faster coral growth and calcification. Moreover, we observed a thermally induced increase in Durusdinium proportion in the PdC holobiont; however, this "symbiont shuffling" in the background was overwhelmed by the overall Cladocopium dominance, which coincided with faster coral bleaching and reduced calcification. CONCLUSIONS These findings support that lineage-specific symbiont dominance is a driver of distinct coral responses to thermal stress. In addition, we found that "symbiont shuffling" may begin with stress-forced, subtle changes in the rare biosphere to eventually trade off growth for increased resilience. Furthermore, the flexibility in corals' association with thermally tolerant symbiont lineages to adapt or acclimatize to future warming oceans should be viewed with conservative optimism as the current rate of environmental changes may outpace the evolutionary capabilities of corals. Video Abstract.
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Affiliation(s)
- Chenying Wang
- Key Laboratory of Marine Ecology Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Xinqing Zheng
- Key Laboratory of Marine Ecology Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
- Observation and Research Station of Wetland Ecosystem in the Beibu Gulf, Ministry of Natural Resources, Beihai, 536015, China.
| | - Hagit Kvitt
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, 31905, Haifa, Israel
- Israel Oceanographic and Limnological Research, National Center for Mariculture, 88112, Eilat, Israel
| | - Huaxia Sheng
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Danye Sun
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Gaofeng Niu
- Marine Genomics and Biotechnology Program, Institute of Marine Science and Technology, Shandong University, Qingdao, 266237, China
| | - Dan Tchernov
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, 31905, Haifa, Israel.
| | - Tuo Shi
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
- Marine Genomics and Biotechnology Program, Institute of Marine Science and Technology, Shandong University, Qingdao, 266237, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangzhou, 510000, China.
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4
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Chan WY, Rudd D, van Oppen MJ. Spatial metabolomics for symbiotic marine invertebrates. Life Sci Alliance 2023; 6:e202301900. [PMID: 37202120 PMCID: PMC10200813 DOI: 10.26508/lsa.202301900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/10/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023] Open
Abstract
Microbial symbionts frequently localize within specific body structures or cell types of their multicellular hosts. This spatiotemporal niche is critical to host health, nutrient exchange, and fitness. Measuring host-microbe metabolite exchange has conventionally relied on tissue homogenates, eliminating dimensionality and dampening analytical sensitivity. We have developed a mass spectrometry imaging workflow for a soft- and hard-bodied cnidarian animal capable of revealing the host and symbiont metabolome in situ, without the need for a priori isotopic labelling or skeleton decalcification. The mass spectrometry imaging method provides critical functional insights that cannot be gleaned from bulk tissue analyses or other presently available spatial methods. We show that cnidarian hosts may regulate microalgal symbiont acquisition and rejection through specific ceramides distributed throughout the tissue lining the gastrovascular cavity. The distribution pattern of betaine lipids showed that once resident, symbionts primarily reside in light-exposed tentacles to generate photosynthate. Spatial patterns of these metabolites also revealed that symbiont identity can drive host metabolism.
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Affiliation(s)
- Wing Yan Chan
- School of BioSciences, University of Melbourne, Parkville, Australia
- Australian Institute of Marine Science, Townsville, Australia
| | - David Rudd
- Monash Institute of Pharmaceutical Sciences, Parkville, Australia
- Melbourne Centre for Nanofabrication, Clayton, Australia
| | - Madeleine Jh van Oppen
- School of BioSciences, University of Melbourne, Parkville, Australia
- Australian Institute of Marine Science, Townsville, Australia
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5
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Davies SW, Gamache MH, Howe-Kerr LI, Kriefall NG, Baker AC, Banaszak AT, Bay LK, Bellantuono AJ, Bhattacharya D, Chan CX, Claar DC, Coffroth MA, Cunning R, Davy SK, del Campo J, Díaz-Almeyda EM, Frommlet JC, Fuess LE, González-Pech RA, Goulet TL, Hoadley KD, Howells EJ, Hume BCC, Kemp DW, Kenkel CD, Kitchen SA, LaJeunesse TC, Lin S, McIlroy SE, McMinds R, Nitschke MR, Oakley CA, Peixoto RS, Prada C, Putnam HM, Quigley K, Reich HG, Reimer JD, Rodriguez-Lanetty M, Rosales SM, Saad OS, Sampayo EM, Santos SR, Shoguchi E, Smith EG, Stat M, Stephens TG, Strader ME, Suggett DJ, Swain TD, Tran C, Traylor-Knowles N, Voolstra CR, Warner ME, Weis VM, Wright RM, Xiang T, Yamashita H, Ziegler M, Correa AMS, Parkinson JE. Building consensus around the assessment and interpretation of Symbiodiniaceae diversity. PeerJ 2023; 11:e15023. [PMID: 37151292 PMCID: PMC10162043 DOI: 10.7717/peerj.15023] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/17/2023] [Indexed: 05/09/2023] Open
Abstract
Within microeukaryotes, genetic variation and functional variation sometimes accumulate more quickly than morphological differences. To understand the evolutionary history and ecology of such lineages, it is key to examine diversity at multiple levels of organization. In the dinoflagellate family Symbiodiniaceae, which can form endosymbioses with cnidarians (e.g., corals, octocorals, sea anemones, jellyfish), other marine invertebrates (e.g., sponges, molluscs, flatworms), and protists (e.g., foraminifera), molecular data have been used extensively over the past three decades to describe phenotypes and to make evolutionary and ecological inferences. Despite advances in Symbiodiniaceae genomics, a lack of consensus among researchers with respect to interpreting genetic data has slowed progress in the field and acted as a barrier to reconciling observations. Here, we identify key challenges regarding the assessment and interpretation of Symbiodiniaceae genetic diversity across three levels: species, populations, and communities. We summarize areas of agreement and highlight techniques and approaches that are broadly accepted. In areas where debate remains, we identify unresolved issues and discuss technologies and approaches that can help to fill knowledge gaps related to genetic and phenotypic diversity. We also discuss ways to stimulate progress, in particular by fostering a more inclusive and collaborative research community. We hope that this perspective will inspire and accelerate coral reef science by serving as a resource to those designing experiments, publishing research, and applying for funding related to Symbiodiniaceae and their symbiotic partnerships.
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Affiliation(s)
- Sarah W. Davies
- Department of Biology, Boston University, Boston, MA, United States
| | - Matthew H. Gamache
- Department of Integrative Biology, University of South Florida, Tampa, FL, United States
| | | | | | - Andrew C. Baker
- Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL, United States
| | - Anastazia T. Banaszak
- Unidad Académica de Sistemas Arrecifales, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Line Kolind Bay
- Australian Institute of Marine Science, Townsville, Australia
| | - Anthony J. Bellantuono
- Department of Biological Sciences, Florida International University, Miami, FL, United States
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, United States
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Danielle C. Claar
- Nearshore Habitat Program, Washington State Department of Natural Resources, Olympia, WA, USA
| | | | - Ross Cunning
- Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium, Chicago, IL, United States
| | - Simon K. Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Javier del Campo
- Institut de Biologia Evolutiva (CSIC - Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | | | - Jörg C. Frommlet
- Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Lauren E. Fuess
- Department of Biology, Texas State University, San Marcos, TX, United States
| | - Raúl A. González-Pech
- Department of Integrative Biology, University of South Florida, Tampa, FL, United States
- Department of Biology, Pennsylvania State University, State College, PA, United States
| | - Tamar L. Goulet
- Department of Biology, University of Mississippi, University, MS, United States
| | - Kenneth D. Hoadley
- Department of Biological Sciences, University of Alabama—Tuscaloosa, Tuscaloosa, AL, United States
| | - Emily J. Howells
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour, NSW, Australia
| | | | - Dustin W. Kemp
- Department of Biology, University of Alabama—Birmingham, Birmingham, Al, United States
| | - Carly D. Kenkel
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Sheila A. Kitchen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Todd C. LaJeunesse
- Department of Biology, Pennsylvania State University, University Park, PA, United States
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut, Mansfield, CT, United States
| | - Shelby E. McIlroy
- Swire Institute of Marine Science, School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Ryan McMinds
- Center for Global Health and Infectious Disease Research, University of South Florida, Tampa, FL, United States
| | | | - Clinton A. Oakley
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Raquel S. Peixoto
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Carlos Prada
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, United States
| | - Hollie M. Putnam
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, United States
| | | | - Hannah G. Reich
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, United States
| | - James Davis Reimer
- Department of Biology, Chemistry and Marine Sciences, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | | | - Stephanie M. Rosales
- The Cooperative Institute For Marine and Atmospheric Studies, Miami, FL, United States
| | - Osama S. Saad
- Department of Biological Oceanography, Red Sea University, Port-Sudan, Sudan
| | - Eugenia M. Sampayo
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Scott R. Santos
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, United States
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Edward G. Smith
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Michael Stat
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Timothy G. Stephens
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, United States
| | - Marie E. Strader
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - David J. Suggett
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Timothy D. Swain
- Department of Marine and Environmental Science, Nova Southeastern University, Dania Beach, FL, United States
| | - Cawa Tran
- Department of Biology, University of San Diego, San Diego, CA, United States
| | - Nikki Traylor-Knowles
- Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL, United States
| | | | - Mark E. Warner
- School of Marine Science and Policy, University of Delaware, Lewes, DE, United States
| | - Virginia M. Weis
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States
| | - Rachel M. Wright
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, United States
| | - Tingting Xiang
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Hiroshi Yamashita
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Ishigaki, Okinawa, Japan
| | - Maren Ziegler
- Department of Animal Ecology & Systematics, Justus Liebig University Giessen (Germany), Giessen, Germany
| | | | - John Everett Parkinson
- Department of Integrative Biology, University of South Florida, Tampa, FL, United States
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6
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Puntin G, Sweet M, Fraune S, Medina M, Sharp K, Weis VM, Ziegler M. Harnessing the Power of Model Organisms To Unravel Microbial Functions in the Coral Holobiont. Microbiol Mol Biol Rev 2022; 86:e0005322. [PMID: 36287022 PMCID: PMC9769930 DOI: 10.1128/mmbr.00053-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Stony corals build the framework of coral reefs, ecosystems of immense ecological and economic importance. The existence of these ecosystems is threatened by climate change and other anthropogenic stressors that manifest in microbial dysbiosis such as coral bleaching and disease, often leading to coral mortality. Despite a significant amount of research, the mechanisms ultimately underlying these destructive phenomena, and what could prevent or mitigate them, remain to be resolved. This is mostly due to practical challenges in experimentation on corals and the highly complex nature of the coral holobiont that also includes bacteria, archaea, protists, and viruses. While the overall importance of these partners is well recognized, their specific contributions to holobiont functioning and their interspecific dynamics remain largely unexplored. Here, we review the potential of adopting model organisms as more tractable systems to address these knowledge gaps. We draw on parallels from the broader biological and biomedical fields to guide the establishment, implementation, and integration of new and emerging model organisms with the aim of addressing the specific needs of coral research. We evaluate the cnidarian models Hydra, Aiptasia, Cassiopea, and Astrangia poculata; review the fast-evolving field of coral tissue and cell cultures; and propose a framework for the establishment of "true" tropical reef-building coral models. Based on this assessment, we also suggest future research to address key aspects limiting our ability to understand and hence improve the response of reef-building corals to future ocean conditions.
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Affiliation(s)
- Giulia Puntin
- Department of Animal Ecology and Systematics, Marine Holobiomics Lab, Justus Liebig University Giessen, Giessen, Germany
| | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby, United Kingdom
| | - Sebastian Fraune
- Institute for Zoology and Organismic Interactions, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Mónica Medina
- Department of Biology, Pennsylvania State University, State College, Pennsylvania, USA
| | - Koty Sharp
- Department of Biology, Marine Biology, and Environmental Science, Roger Williams University, Bristol, Rhode Island, USA
| | - Virginia M. Weis
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
| | - Maren Ziegler
- Department of Animal Ecology and Systematics, Marine Holobiomics Lab, Justus Liebig University Giessen, Giessen, Germany
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7
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Maruyama S, Unsworth JR, Sawiccy V, Weis VM. Algae from Aiptasia egesta are robust representations of Symbiodiniaceae in the free-living state. PeerJ 2022; 10:e13796. [PMID: 35923894 PMCID: PMC9341449 DOI: 10.7717/peerj.13796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/06/2022] [Indexed: 01/18/2023] Open
Abstract
Many cnidarians rely on their dinoflagellate partners from the family Symbiodiniaceae for their ecological success. Symbiotic species of Symbiodiniaceae have two distinct life stages: inside the host, in hospite, and outside the host, ex hospite. Several aspects of cnidarian-algal symbiosis can be understood by comparing these two life stages. Most commonly, algae in culture are used in comparative studies to represent the ex hospite life stage, however, nutrition becomes a confounding variable for this comparison because algal culture media is nutrient rich, while algae in hospite are sampled from hosts maintained in oligotrophic seawater. In contrast to cultured algae, expelled algae may be a more robust representation of the ex hospite state, as the host and expelled algae are in the same seawater environment, removing differences in culture media as a confounding variable. Here, we studied the physiology of algae released from the sea anemone Exaiptasia diaphana (commonly called Aiptasia), a model system for the study of coral-algal symbiosis. In Aiptasia, algae are released in distinct pellets, referred to as egesta, and we explored its potential as an experimental system to represent Symbiodiniaceae in the ex hospite state. Observation under confocal and differential interference contrast microscopy revealed that egesta contained discharged nematocysts, host tissue, and were populated by a diversity of microbes, including protists and cyanobacteria. Further experiments revealed that egesta were released at night. In addition, algae in egesta had a higher mitotic index than algae in hospite, were photosynthetically viable for at least 48 hrs after expulsion, and could competently establish symbiosis with aposymbiotic Aiptasia. We then studied the gene expression of nutrient-related genes and studied their expression using qPCR. From the genes tested, we found that algae from egesta closely mirrored gene expression profiles of algae in hospite and were dissimilar to those of cultured algae, suggesting that algae from egesta are in a nutritional environment that is similar to their in hospite counterparts. Altogether, evidence is provided that algae from Aiptasia egesta are a robust representation of Symbiodiniaceae in the ex hospite state and their use in experiments can improve our understanding of cnidarian-algal symbiosis.
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Affiliation(s)
- Shumpei Maruyama
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States of America
| | - Julia R. Unsworth
- Department of Biology, Lewis and Clark College, Portland, OR, United States of America
| | - Valeri Sawiccy
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States of America
| | | | - Virginia M. Weis
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States of America
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8
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Morrow KM, Pankey MS, Lesser MP. Community structure of coral microbiomes is dependent on host morphology. MICROBIOME 2022; 10:113. [PMID: 35902906 PMCID: PMC9331152 DOI: 10.1186/s40168-022-01308-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The importance of symbiosis has long been recognized on coral reefs, where the photosynthetic dinoflagellates of corals (Symbiodiniaceae) are the primary symbiont. Numerous studies have now shown that a diverse assemblage of prokaryotes also make-up part of the microbiome of corals. A subset of these prokaryotes is capable of fixing nitrogen, known as diazotrophs, and is also present in the microbiome of scleractinian corals where they have been shown to supplement the holobiont nitrogen budget. Here, an analysis of the microbiomes of 16 coral species collected from Australia, Curaçao, and Hawai'i using three different marker genes (16S rRNA, nifH, and ITS2) is presented. These data were used to examine the effects of biogeography, coral traits, and ecological life history characteristics on the composition and diversity of the microbiome in corals and their diazotrophic communities. RESULTS The prokaryotic microbiome community composition (i.e., beta diversity) based on the 16S rRNA gene varied between sites and ecological life history characteristics, but coral morphology was the most significant factor affecting the microbiome of the corals studied. For 15 of the corals studied, only two species Pocillopora acuta and Seriotopora hystrix, both brooders, showed a weak relationship between the 16S rRNA gene community structure and the diazotrophic members of the microbiome using the nifH marker gene, suggesting that many corals support a microbiome with diazotrophic capabilities. The order Rhizobiales, a taxon that contains primarily diazotrophs, are common members of the coral microbiome and were eight times greater in relative abundances in Hawai'i compared to corals from either Curacao or Australia. However, for the diazotrophic component of the coral microbiome, only host species significantly influenced the composition and diversity of the community. CONCLUSIONS The roles and interactions between members of the coral holobiont are still not well understood, especially critical functions provided by the coral microbiome (e.g., nitrogen fixation), and the variation of these functions across species. The findings presented here show the significant effect of morphology, a coral "super trait," on the overall community structure of the microbiome in corals and that there is a strong association of the diazotrophic community within the microbiome of corals. However, the underlying coral traits linking the effects of host species on diazotrophic communities remain unknown. Video Abstract.
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Affiliation(s)
- Kathleen M Morrow
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
- Present address: Thomas Jefferson High School for Science and Technology, 6560 Braddock Rd, Alexandria, VA, 22312, USA
| | - M Sabrina Pankey
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Michael P Lesser
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA.
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9
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Immunolocalization of Metabolite Transporter Proteins in a Model Cnidarian-Dinoflagellate Symbiosis. Appl Environ Microbiol 2022; 88:e0041222. [PMID: 35678605 DOI: 10.1128/aem.00412-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bidirectional nutrient flow between partners is integral to the cnidarian-dinoflagellate endosymbiosis. However, our current knowledge of the transporter proteins that regulate nutrient and metabolite trafficking is nascent. Four transmembrane transporters that likely play an important role in interpartner nitrogen and carbon exchange were investigated with immunocytochemistry in the model sea anemone Exaiptasia diaphana ("Aiptasia"; strain NZ1): ammonium transporter 1 (AMT1), V-type proton ATPase (VHA), facilitated glucose transporter member 8 (GLUT8), and aquaporin-3 (AQP3). Anemones lacking symbionts were compared with those in symbiosis with either their typical, homologous dinoflagellate symbiont, Breviolum minutum, or the heterologous species, Durusdinium trenchii and Symbiodinium microadriaticum. AMT1 and VHA were only detected in symbiotic Aiptasia, irrespective of symbiont type. However, GLUT8 and AQP3 were detected in both symbiotic and aposymbiotic states. All transporters were localized to both the epidermis and gastrodermis, though localization patterns in host tissues were heavily influenced by symbiont identity, with S. microadriaticum-colonized anemones showing the most distinct patterns. These patterns suggested disruption of fixed carbon and inorganic nitrogen fluxes when in symbiosis with heterologous versus homologous symbionts. This study enhances our understanding of nutrient transport and host-symbiont integration, while providing a platform for further investigation of nutrient transporters and the host-symbiont interface in the cnidarian-dinoflagellate symbiosis. IMPORTANCE Coral reefs are in serious decline, in particular due to the thermally induced dysfunction of the cnidarian-dinoflagellate symbiosis that underlies their success. Yet our ability to react to this crisis is hindered by limited knowledge of how this symbiosis functions. Indeed, we still have much to learn about the cellular integration that determines whether a particular host-symbiont combination can persist, and hence whether corals might be able to adapt by acquiring new, more thermally resistant symbionts. Here, we employed immunocytochemistry to localize and quantify key nutrient transporters in tissues of the sea anemone Aiptasia, a globally adopted model system for this symbiosis, and compared the expression of these transporters when the host is colonized by native versus nonnative symbionts. We showed a clear link between transporter expression and symbiont identity, elucidating the cellular events that dictate symbiosis success, and we provide a methodological platform for further examination of cellular integration in this ecologically important symbiosis.
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10
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Hoang KL, Choi H, Gerardo NM, Morran LT. Coevolution's conflicting role in the establishment of beneficial associations. Evolution 2022; 76:1073-1081. [PMID: 35304743 PMCID: PMC9310579 DOI: 10.1111/evo.14472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/28/2022] [Accepted: 02/14/2022] [Indexed: 01/21/2023]
Abstract
Reciprocal adaptation between hosts and symbionts can drive the maintenance of symbioses, resulting in coevolution and beneficial genotypic interactions. Consequently, hosts may experience decreased fitness when paired with nonsympatric partners compared to sympatric symbionts. However, coevolution does not preclude conflict-host and symbiont can act to advance their own fitness interests, which do not necessarily align with those of their partner. Despite coevolution's importance in extant symbioses, we know little about its role in shaping the origin of symbioses. Here, we tested the role of coevolution in establishing a novel association by experimentally (co)evolving a host with a protective bacterium under environmental stress. Although evolution in the presence of nonevolving bacteria facilitated host adaptation, co-passaged hosts did not exhibit greater adaptation rates than hosts paired with nonevolving bacteria. Furthermore, co-passaged hosts exhibited greater fecundity when paired with sympatric, co-passaged bacteria compared to co-passaged bacteria with which they did not share an evolutionary history. Thus, shared evolutionary history between the hosts and microbes actually reduced host fitness and has the potential to impede evolution of new beneficial associations.
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Affiliation(s)
- Kim L. Hoang
- Department of BiologyEmory UniversityAtlantaGeorgia30322
| | - Heidi Choi
- Department of BiologyEmory UniversityAtlantaGeorgia30322
| | | | - Levi T. Morran
- Department of BiologyEmory UniversityAtlantaGeorgia30322
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11
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Goodheart JA, Barone V, Lyons DC. Movement and storage of nematocysts across development in the nudibranch Berghia stephanieae (Valdés, 2005). Front Zool 2022; 19:16. [PMID: 35436919 PMCID: PMC9016961 DOI: 10.1186/s12983-022-00460-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/31/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intracellular sequestration requires specialized cellular and molecular mechanisms allowing a predator to retain and use specific organelles that once belonged to its prey. Little is known about how common cellular mechanisms, like phagocytosis, can be modified to selectively internalize and store foreign structures. One form of defensive sequestration involves animals that sequester stinging organelles (nematocysts) from their cnidarian prey. While it has been hypothesized that nematocysts are identified by specialized phagocytic cells for internalization and storage, little is known about the cellular and developmental mechanisms of this process in any metazoan lineage. This knowledge gap is mainly due to a lack of genetically tractable model systems among predators and their cnidarian prey. RESULTS Here, we introduce the nudibranch Berghia stephanieae as a model system to investigate the cell, developmental, and physiological features of nematocyst sequestration selectivity. We first show that B. stephanieae, which feeds on Exaiptasia diaphana, selectively sequesters nematocysts over other E. diaphana tissues found in their digestive gland. Using confocal microscopy, we document that nematocyst sequestration begins shortly after feeding and prior to the formation of the appendages (cerata) where the organ responsible for sequestration (the cnidosac) resides in adults. This finding is inconsistent with previous studies that place the formation of the cnidosac after cerata emerge. Our results also show, via live imaging assays, that both nematocysts and dinoflagellates can enter the nascent cnidosac structure. This result indicates that selectivity for nematocysts occurs inside the cnidosac in B. stephanieae, likely in the cnidophage cells themselves. CONCLUSIONS Our work highlights the utility of B. stephanieae for future research, because: (1) this species can be cultured in the laboratory, which provides access to all developmental stages, and (2) the transparency of early juveniles makes imaging techniques (and therefore cell and molecular assays) feasible. Our results pave the way for future studies using live imaging and targeted gene editing to identify the molecular mechanisms involved in nematocyst sequestration. Further studies of nematocyst sequestration in B. stephanieae will also allow us to investigate how common cellular mechanisms like phagocytosis can be modified to selectively internalize and store foreign structures.
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Affiliation(s)
- Jessica A Goodheart
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 92037, USA.
| | - Vanessa Barone
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 92037, USA
| | - Deirdre C Lyons
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 92037, USA
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12
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Tsang Min Ching SJ, Chan WY, Perez-Gonzalez A, Hillyer KE, Buerger P, van Oppen MJH. Colonization and metabolite profiles of homologous, heterologous and experimentally evolved algal symbionts in the sea anemone Exaiptasia diaphana. ISME COMMUNICATIONS 2022; 2:30. [PMID: 37938648 PMCID: PMC9723793 DOI: 10.1038/s43705-022-00114-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/17/2022] [Accepted: 03/01/2022] [Indexed: 07/30/2023]
Abstract
The sea anemone, Exaiptasia diaphana, is a model of coral-dinoflagellate (Symbiodiniaceae) symbiosis. However, little is known of its potential to form symbiosis with Cladocopium-a key Indo-Pacific algal symbiont of scleractinian corals, nor the host nutritional consequences of such an association. Aposymbiotic anemones were inoculated with homologous algal symbionts, Breviolum minutum, and seven heterologous strains of Cladocopium C1acro (wild-type and heat-evolved) under ambient conditions. Despite lower initial algal cell density, Cladocopium C1acro-anemeones achieved similar cell densities as B. minutum-anemones by week 77. Wild-type and heat-evolved Cladocopium C1acro showed similar colonization patterns. Targeted LC-MS-based metabolomics revealed that almost all significantly different metabolites in the host and Symbiodiniaceae fractions were due to differences between Cladocopium C1acro and B. minutum, with little difference between heat-evolved and wild-type Cladocopium C1acro at week 9. The algal fraction of Cladocopium C1acro-anemones was enriched in metabolites related to nitrogen storage, while the host fraction of B. minutum-anemones was enriched in sugar-related metabolites. Compared to B. minutum, Cladocopium C1acro is likely slightly less nutritionally beneficial to the host under ambient conditions, but more capable of maintaining its own growth when host nitrogen supply is limited. Our findings demonstrate the value of E. diaphana to study experimentally evolved Cladocopium.
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Affiliation(s)
| | - Wing Yan Chan
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia.
| | - Alexis Perez-Gonzalez
- Melbourne Cytometry Platform, University of Melbourne, Parkville, VIC, Australia
- Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute of Infection and Immunity, Parkville, VIC, Australia
| | | | - Patrick Buerger
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
- Applied Biosciences, Macquarie University, North Ryde, NSW, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
- Australian Institute of Marine Science, Townsville, QLD, Australia
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13
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Matsuda SB, Chakravarti LJ, Cunning R, Huffmyer AS, Nelson CE, Gates RD, van Oppen MJH. Temperature-mediated acquisition of rare heterologous symbionts promotes survival of coral larvae under ocean warming. GLOBAL CHANGE BIOLOGY 2022; 28:2006-2025. [PMID: 34957651 PMCID: PMC9303745 DOI: 10.1111/gcb.16057] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Reef-building corals form nutritional symbioses with endosymbiotic dinoflagellates (Symbiodiniaceae), a relationship that facilitates the ecological success of coral reefs. These symbionts are mostly acquired anew each generation from the environment during early life stages ("horizontal transmission"). Symbiodiniaceae species exhibit trait variation that directly impacts the health and performance of the coral host under ocean warming. Here, we test the capacity for larvae of a horizontally transmitting coral, Acropora tenuis, to establish symbioses with Symbiodiniaceae species in four genera that have varying thermal thresholds (the common symbiont genera, Cladocopium and Durusdinium, and the less common Fugacium and Gerakladium). Over a 2-week period in January 2018, a series of both no-choice and four-way choice experiments were conducted at three temperatures (27, 30, and 31°C). Symbiont acquisition success and cell proliferation were measured in individual larvae. Larvae successfully acquired and maintained symbionts of all four genera in no-choice experiments, and >80% of larvae were infected with at least three genera when offered a four-way choice. Unexpectedly, Gerakladium symbionts increased in dominance over time, and at high temperatures outcompeted Durusdinium, which is regarded as thermally tolerant. Although Fugacium displayed the highest thermal tolerance in culture and reached similar cell densities to the other three symbionts at 31°C, it remained a background symbiont in choice experiments, suggesting host preference for other symbiont species. Larval survivorship at 1 week was highest in larvae associated with Gerakladium and Fugacium symbionts at 27 and 30°C, however at 31°C, mortality was similar for all treatments. We hypothesize that symbionts that are currently rare in corals (e.g., Gerakladium) may become more common and widespread in early life stages under climate warming. Uptake of such symbionts may function as a survival strategy in the wild, and has implications for reef restoration practices that use sexually produced coral stock.
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Affiliation(s)
- Shayle B. Matsuda
- Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at MānoaKāne‘oheHawai‘iUSA
| | | | - Ross Cunning
- Daniel P. Haerther Center for Conservation and ResearchJohn G. Shedd AquariumChicagoIllinoisUSA
| | - Ariana S. Huffmyer
- Department of Biological SciencesUniversity of Rhode IslandKingstonRhode IslandUSA
| | - Craig E. Nelson
- Daniel K. Inouye Center for Microbial Oceanography: Research and EducationDepartment of Oceanography and Sea Grant College ProgramUniversity of Hawai‘i at MānoaHonoluluHawai‘iUSA
| | - Ruth D. Gates
- Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at MānoaKāne‘oheHawai‘iUSA
| | - Madeleine J. H. van Oppen
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- School of BioSciencesThe University of MelbourneParkvilleVictoriaAustralia
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14
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Dungan AM, Hartman LM, Blackall LL, van Oppen MJH. Exploring microbiome engineering as a strategy for improved thermal tolerance in Exaiptasia diaphana. J Appl Microbiol 2022; 132:2940-2956. [PMID: 35104027 PMCID: PMC9303619 DOI: 10.1111/jam.15465] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/08/2021] [Accepted: 01/24/2022] [Indexed: 11/28/2022]
Abstract
Aims Fourteen percent of all living coral, equivalent to more than all the coral on the Great Barrier Reef, has died in the past decade as a result of climate change‐driven bleaching. Inspired by the ‘oxidative stress theory of coral bleaching’, we investigated whether a bacterial consortium designed to scavenge free radicals could integrate into the host microbiome and improve thermal tolerance of the coral model, Exaiptasia diaphana. Methods and Results E. diaphana anemones were inoculated with a consortium of high free radical scavenging (FRS) bacteria, a consortium of congeneric low FRS bacteria, or sterile seawater as a control, then exposed to elevated temperature. Increases in the relative abundance of Labrenzia during the first 2 weeks following the last inoculation provided evidence for temporary inoculum integration into the E. diaphana microbiome. Initial uptake of other consortium members was inconsistent, and these bacteria did not persist either in E. diaphana’s microbiome over time. Given their non‐integration into the host microbiome, the ability of the FRS consortium to mitigate thermal stress could not be assessed. Importantly, there were no physiological impacts (negative or positive) of the bacterial inoculations on the holobiont. Conclusions The introduced bacteria were not maintained in the anemone microbiome over time, thus, their protective effect is unknown. Achieving long‐term integration of bacteria into cnidarian microbiomes remains a research priority. Significance and Impact of the Study Microbiome engineering strategies to mitigate coral bleaching may assist coral reefs in their persistence until climate change has been curbed. This study provides insights that will inform microbiome manipulation approaches in coral bleaching mitigation research.
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Affiliation(s)
- Ashley M Dungan
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Leon M Hartman
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia.,Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Linda L Blackall
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia.,Australian Institute of Marine Science, Townsville, Australia
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15
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Turnham KE, Wham DC, Sampayo E, LaJeunesse TC. Mutualistic microalgae co-diversify with reef corals that acquire symbionts during egg development. THE ISME JOURNAL 2021; 15:3271-3285. [PMID: 34012104 PMCID: PMC8528872 DOI: 10.1038/s41396-021-01007-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 04/23/2021] [Accepted: 05/04/2021] [Indexed: 02/04/2023]
Abstract
The application of molecular genetics has reinvigorated and improved how species are defined and investigated scientifically, especially for morphologically cryptic micro-organisms. Here we show how species recognition improves understanding of the ecology and evolution of mutualisms between reef-building corals and their mutualistic dinoflagellates (i.e. Symbiodiniaceae). A combination of genetic, ecological, and morphological evidence defines two sibling species of Cladocopium (formerly Symbiodinium Clade C), specific only to host corals in the common genus Pocillopora, which transmit their obligate symbionts during oogenesis. Cladocopium latusorum sp. nov. is symbiotic with P. grandis/meandrina while the smaller-celled C. pacificum sp. nov. associates with P. verrucosa. Both symbiont species form mutualisms with Pocillopora that brood their young. Populations of each species, like their hosts, are genetically well connected across the tropical and subtropical Pacific Ocean, indicating a capacity for long-range dispersal. A molecular clock approximates their speciation during the late Pliocene or early Pleistocene as Earth underwent cycles of precipitous cooling and warming; and corresponds to when their hosts were also diversifying. The long temporal and spatial maintenance of high host fidelity, as well as genetic connectivity across thousands of kilometers, indicates that distinct ecological attributes and close evolutionary histories will restrain the adaptive responses of corals and their specialized symbionts to rapid climate warming.
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Affiliation(s)
| | - Drew C Wham
- Penn State University, University Park, PA, USA
| | | | - Todd C LaJeunesse
- Penn State University, University Park, PA, USA.
- Penn State Institutes of Energy and the Environment, University Park, PA, USA.
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16
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Fujiwara Y, Kawamura I, Reimer JD, Parkinson JE. Zoantharian Endosymbiont Community Dynamics During a Stress Event. Front Microbiol 2021; 12:674026. [PMID: 34122387 PMCID: PMC8193574 DOI: 10.3389/fmicb.2021.674026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Coral reefs are complex ecosystems composed of many interacting species. One ecologically important group consists of zoantharians, which are closely related to reef-building corals. Like corals, zoantharians form mutualistic symbioses with dinoflagellate micro-algae (family Symbiodiniaceae), but their associations remain underexplored. To examine the degree to which zoantharians exhibit altered symbiont dynamics under changing environmental conditions, we reciprocally transplanted colonies of Zoanthus sansibaricus between intertidal (2 m) and subtidal (26 m) depths within a reef in Okinawa, Japan. At this location, Z. sansibaricus can associate with three Symbiodiniaceae species from two genera distributed along a light and depth gradient. We developed species-specific molecular assays and sampled colonies pre- and post-transplantation to analyze symbiont community diversity. Despite large environmental differences across depths, we detected few symbiont compositional changes resulting from transplantation stress. Colonies sourced from the intertidal zone associated with mixtures of a "shallow" Symbiodinium sp. and a "shallow" Cladocopium sp. independent of whether they were transplanted to shallow or deep waters. Colonies sourced from the subtidal zone were dominated by a "deep" Cladocopium sp. regardless of transplant depth. Subtidal colonies brought to shallow depths did not transition to the presumably high-light adapted shallow symbionts present in the new environment, but rather bleached and died. These patterns mirror observations of highly stable coral-algal associations subjected to depth transplantation. Our results indicate that Zoanthus-Symbiodiniaceae symbioses remain stable despite stress, suggesting these important reef community members have relatively low capacity to shuffle to more stress-tolerant micro-algae in response to ongoing climate change.
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Affiliation(s)
- Yu Fujiwara
- Molecular Invertebrate Systematics and Ecology Laboratory, Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Japan.,Nakajima Suisan Co. Ltd., Tokyo, Japan
| | - Iori Kawamura
- Molecular Invertebrate Systematics and Ecology Laboratory, Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Japan
| | - James Davis Reimer
- Molecular Invertebrate Systematics and Ecology Laboratory, Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Japan.,Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Japan
| | - John Everett Parkinson
- Molecular Invertebrate Systematics and Ecology Laboratory, Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Japan.,Department of Integrative Biology, University of South Florida, Tampa, FL, United States
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17
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Goulet TL, Goulet D. Climate Change Leads to a Reduction in Symbiotic Derived Cnidarian Biodiversity on Coral Reefs. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.636279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Symbiotic relationships enable partners to thrive and survive in habitats where they would either not be as successful, or potentially not exist, without the symbiosis. The coral reef ecosystem, and its immense biodiversity, relies on the symbioses between cnidarians (e.g., scleractinian corals, octocorals, sea anemones, jellyfish) and multiple organisms including dinoflagellate algae (family Symbiodiniaceae), bivalves, crabs, shrimps, and fishes. In this review, we discuss the ramifications of whether coral reef cnidarian symbioses are obligatory, whereby at least one of the partners must be in the symbiosis in order to survive or are facultative. Furthermore, we cover the consequences of cnidarian symbioses exhibiting partner flexibility or fidelity. Fidelity, where a symbiotic partner can only engage in symbiosis with a subset of partners, may be absolute or context dependent. Current literature demonstrates that many cnidarian symbioses are highly obligative and appear to exhibit absolute fidelity. Consequently, for many coral reef cnidarian symbioses, surviving changing environmental conditions will depend on the robustness and potential plasticity of the existing host-symbiont(s) combination. If environmental conditions detrimentally affect even one component of this symbiotic consortium, it may lead to a cascade effect and the collapse of the entire symbiosis. Symbiosis is at the heart of the coral reef ecosystem, its existence, and its high biodiversity. Climate change may cause the demise of some of the cnidarian symbioses, leading to subsequent reduction in biodiversity on coral reefs.
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18
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Clowez S, Renicke C, Pringle JR, Grossman AR. Impact of Menthol on Growth and Photosynthetic Function of Breviolum Minutum (Dinoflagellata, Dinophyceae, Symbiodiniaceae) and Interactions with its Aiptasia Host. JOURNAL OF PHYCOLOGY 2021; 57:245-257. [PMID: 33025575 DOI: 10.1111/jpy.13081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 09/01/2020] [Accepted: 09/19/2020] [Indexed: 06/11/2023]
Abstract
Environmental change, including global warming and chemical pollution, can compromise cnidarian-(e.g., coral-) dinoflagellate symbioses and cause coral bleaching. Understanding the mechanisms that regulate these symbioses will inform strategies for sustaining healthy coral-reef communities. A model system for corals is the symbiosis between the sea anemone Exaiptasia pallida (common name Aiptasia) and its dinoflagellate partners (family Symbiodiniaceae). To complement existing studies of the interactions between these organisms, we examined the impact of menthol, a reagent often used to render cnidarians aposymbiotic, on the dinoflagellate Breviolum minutum, both in culture and in hospite. In both environments, the growth and photosynthesis of this alga were compromised at either 100 or 300 µM menthol. We observed reduction in PSII and PSI functions, the abundances of reaction-center proteins, and, at 300 µM menthol, of total cellular proteins. Interestingly, for free-living algae exposed to 100 µM menthol, an initial decline in growth, photosynthetic activities, pigmentation, and protein abundances reversed after 5-15 d, eventually approaching control levels. This behavior was observed in cells maintained in continuous light, but not in cells experiencing a light-dark regimen, suggesting that B. minutum can detoxify menthol or acclimate and repair damaged photosynthetic complexes in a light- and/or energy-dependent manner. Extended exposures of cultured algae to 300 µM menthol ultimately resulted in algal death. Most symbiotic anemones were also unable to survive this menthol concentration for 30 d. Additionally, cells impaired for photosynthesis by pre-treatment with 300 µM menthol exhibited reduced efficiency in re-populating the anemone host.
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Affiliation(s)
- Sophie Clowez
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, California, 94305, USA
| | - Christian Renicke
- Department of Genetics, Stanford University, Stanford, California, 94305, USA
| | - John R Pringle
- Department of Genetics, Stanford University, Stanford, California, 94305, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, California, 94305, USA
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Umeki M, Yamashita H, Suzuki G, Sato T, Ohara S, Koike K. Fecal pellets of giant clams as a route for transporting Symbiodiniaceae to corals. PLoS One 2020; 15:e0243087. [PMID: 33326418 PMCID: PMC7743926 DOI: 10.1371/journal.pone.0243087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/13/2020] [Indexed: 11/19/2022] Open
Abstract
Because more than 80% of species of gamete-spawning corals, including most Acroporidae species, do not inherit Symbiodiniaceae from their parents, they must acquire symbiont cells from sources in their environment. To determine whether photosynthetically competent Symbiodiniaceae expelled as fecal pellets from giant clams are capable of colonizing corals, we conducted laboratory experiments in which planula larvae of Acropora tenuis were inoculated with the cells in fecal pellets obtained from Tridacna crocea. T. crocea fecal pellets were administered once a day, and three days later, cells of Symbiodiniaceae from the fecal pellets had been taken up by the coral larvae. T. crocea fecal pellets were not supplied from the 4th day until the 8th day, and the cell densities in the larvae increased until the 8th day, which indicated the successful colonization by Symbiodiniaceae. The control group exhibited the highest mean percentage of larvae (100%) that were successfully colonized by culture strains of Symbiodiniaceae, and larvae inoculated with fecal pellets reached a colonization percentage of 66.7 ~ 96.7% on the 8th day. The highest colonization rate was achieved with the fecal pellets containing cells with high photosynthetic competency (Fv/Fm). Interestingly, the genetic composition of Symbiodiniaceae in the larvae retrieved on the 8th day differed from that in the fecal pellets and showed exclusive domination of the genus Symbiodinium. A minor but significant population of the genus Cladocopium in the fecal pellets was not inherited by the larvae. These experiments provided the first demonstration that the Symbiodiniaceae from tridacnine clams provided via fecal pellets can colonize and even proliferate in coral larvae.
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Affiliation(s)
- Masami Umeki
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan
| | - Hiroshi Yamashita
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Okinawa, Japan
| | - Go Suzuki
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Okinawa, Japan
| | - Taiki Sato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan
| | - Shizuka Ohara
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan
- * E-mail:
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20
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Rosset SL, Oakley CA, Ferrier-Pagès C, Suggett DJ, Weis VM, Davy SK. The Molecular Language of the Cnidarian-Dinoflagellate Symbiosis. Trends Microbiol 2020; 29:320-333. [PMID: 33041180 DOI: 10.1016/j.tim.2020.08.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 12/18/2022]
Abstract
The cnidarian-dinoflagellate symbiosis is of huge importance as it underpins the success of coral reefs, yet we know very little about how the host cnidarian and its dinoflagellate endosymbionts communicate with each other to form a functionally integrated unit. Here, we review the current knowledge of interpartner molecular signaling in this symbiosis, with an emphasis on lipids, glycans, reactive species, biogenic volatiles, and noncoding RNA. We draw upon evidence of these compounds from recent omics-based studies of cnidarian-dinoflagellate symbiosis and discuss the signaling roles that they play in other, better-studied symbioses. We then consider how improved knowledge of interpartner signaling might be used to develop solutions to the coral reef crisis by, for example, engineering more thermally resistant corals.
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Affiliation(s)
- Sabrina L Rosset
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
| | - Clinton A Oakley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
| | | | - David J Suggett
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, PO Box 123, Broadway NSW 2007, Australia
| | - Virginia M Weis
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand.
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21
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Herrera M, Klein SG, Schmidt‐Roach S, Campana S, Cziesielski MJ, Chen JE, Duarte CM, Aranda M. Unfamiliar partnerships limit cnidarian holobiont acclimation to warming. GLOBAL CHANGE BIOLOGY 2020; 26:5539-5553. [PMID: 32627905 PMCID: PMC7539969 DOI: 10.1111/gcb.15263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/23/2020] [Indexed: 05/08/2023]
Abstract
Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.
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Affiliation(s)
- Marcela Herrera
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Shannon G. Klein
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Sebastian Schmidt‐Roach
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Sara Campana
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
- Present address:
Faculty of ScienceInstitute for Biodiversity and Ecosystem DynamicsUniversity of Amsterdam1090 GEAmsterdamThe Netherlands
| | - Maha J. Cziesielski
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Jit Ern Chen
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
- Present address:
School of Science and TechnologyDepartment of Biological SciencesSunway UniversitySubang JayaSelangorMalaysia
| | - Carlos M. Duarte
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Manuel Aranda
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
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22
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Temperature transcends partner specificity in the symbiosis establishment of a cnidarian. ISME JOURNAL 2020; 15:141-153. [PMID: 32934356 PMCID: PMC7852570 DOI: 10.1038/s41396-020-00768-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 08/13/2020] [Accepted: 09/02/2020] [Indexed: 12/21/2022]
Abstract
Coral reef research has predominantly focused on the effect of temperature on the breakdown of coral-dinoflagellate symbioses. However, less is known about how increasing temperature affects the establishment of new coral-dinoflagellate associations. Inter-partner specificity and environment-dependent colonization are two constraints proposed to limit the acquisition of more heat tolerant symbionts. Here, we investigated the symbiotic dynamics of various photosymbionts in different host genotypes under “optimal” and elevated temperature conditions. To do this, we inoculated symbiont-free polyps of the sea anemone Exaiptasia pallida originating from Hawaii (H2), North Carolina (CC7), and the Red Sea (RS) with the same mixture of native symbiont strains (Breviolum minutum, Symbiodinium linucheae, S. microadriaticum, and a Breviolum type from the Red Sea) at 25 and 32 °C, and assessed their ITS2 composition, colonization rates, and PSII photochemical efficiency (Fv/Fm). Symbiont communities across thermal conditions differed significantly for all hosts, suggesting that temperature rather than partner specificity had a stronger effect on symbiosis establishment. Overall, we detected higher abundances of more heat resistant Symbiodiniaceae types in the 32 °C treatments. Our data further showed that PSII photophysiology under elevated temperature improved with thermal pre-exposure (i.e., higher Fv/Fm), yet, this effect depended on host genotype and was influenced by active feeding as photochemical efficiency dropped in response to food deprivation. These findings highlight the role of temperature and partner fidelity in the establishment and performance of symbiosis and demonstrate the importance of heterotrophy for symbiotic cnidarians to endure and recover from stress.
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23
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Sproles AE, Oakley CA, Krueger T, Grossman AR, Weis VM, Meibom A, Davy SK. Sub-cellular imaging shows reduced photosynthetic carbon and increased nitrogen assimilation by the non-native endosymbiont Durusdinium trenchii in the model cnidarian Aiptasia. Environ Microbiol 2020; 22:3741-3753. [PMID: 32592285 DOI: 10.1111/1462-2920.15142] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/26/2020] [Accepted: 06/23/2020] [Indexed: 01/18/2023]
Abstract
Hosting different symbiont species can affect inter-partner nutritional fluxes within the cnidarian-dinoflagellate symbiosis. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we measured the spatial incorporation of photosynthetically fixed 13 C and heterotrophically derived 15 N into host and symbiont cells of the model symbiotic cnidarian Aiptasia (Exaiptasia pallida) when colonized with its native symbiont Breviolum minutum or the non-native Durusdinium trenchii. Breviolum minutum exhibited high photosynthetic carbon assimilation per cell and translocation to host tissue throughout symbiosis establishment, whereas D. trenchii assimilated significantly less carbon, but obtained more host nitrogen. These findings suggest that D. trenchii has less potential to provide photosynthetically fixed carbon to the host despite obtaining considerable amounts of heterotrophically derived nitrogen. These sub-cellular events help explain previous observations that demonstrate differential effects of D. trenchii compared to B. minutum on the host transcriptome, proteome, metabolome and host growth and asexual reproduction. Together, these differential effects suggest that the non-native host-symbiont pairing is sub-optimal with respect to the host's nutritional benefits under normal environmental conditions. This contributes to our understanding of the ways in which metabolic integration impacts the benefits of a symbiotic association, and the potential evolution of novel host-symbiont pairings.
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Affiliation(s)
- Ashley E Sproles
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand.,The California Center for Algae Biotechnology, Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Clinton A Oakley
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Thomas Krueger
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland.,Department of Biochemistry, University of Cambridge, Hopkins Building, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, California, 94305, USA
| | - Virginia M Weis
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97331, USA
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
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24
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Newkirk CR, Frazer TK, Martindale MQ, Schnitzler CE. Adaptation to Bleaching: Are Thermotolerant Symbiodiniaceae Strains More Successful Than Other Strains Under Elevated Temperatures in a Model Symbiotic Cnidarian? Front Microbiol 2020; 11:822. [PMID: 32431680 PMCID: PMC7214872 DOI: 10.3389/fmicb.2020.00822] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/06/2020] [Indexed: 01/01/2023] Open
Abstract
The ability of some symbiotic cnidarians to resist and better withstand stress factors that cause bleaching is a trait that is receiving increased attention. The adaptive bleaching hypothesis postulates that cnidarians that can form a stable symbiosis with thermotolerant Symbiodiniaceae strains may cope better with increasing seawater temperatures. We used polyps of the scyphozoan, Cassiopea xamachana, as a model system to test symbiosis success under heat stress. We sought to determine: (1) if aposymbiotic C. xamachana polyps could establish and maintain a symbiosis with both native and non-native strains of Symbiodiniaceae that all exhibit different tolerances to heat, (2) whether polyps with these newly acquired Symbiodiniaceae strains would strobilate (produce ephyra), and (3) if thermally tolerant Symbiodiniaceae strains that established and maintained a symbiosis exhibited greater success in response to heat stress (even if they are not naturally occurring in Cassiopea). Following recolonization of aposymbiotic C. xamachana polyps with different strains, we found that: (1) strains Smic, Stri, Slin, and Spil all established a stable symbiosis that promoted strobilation and (2) strains Bmin1 and Bmin2 did not establish a stable symbiosis and strobilation did not occur. Strains Smic, Stri, Slin, and Spil were used in a subsequent bleaching experiment; each of the strains was introduced to a subset of aposymbiotic polyps and once polyp tissues were saturated with symbionts they were subjected to elevated temperatures - 32°C and 34°C - for 2 weeks. Our findings indicate that, in general, pairings of polyps with Symbiodiniaceae strains that are native to Cassiopea (Stri and Smic) performed better than a non-native strain (Slin) even though this strain has a high thermotolerance. This suggests a degree of partner specificity that may limit the adaptive potential of certain cnidarians to increased ocean warming. We also observed that the free-living, non-native thermotolerant strain Spil was relatively successful in resisting bleaching during experimental trials. This suggests that free-living Symbiodiniaceae may provide a supply of potentially "new" thermotolerant strains to cnidarians following a bleaching event.
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Affiliation(s)
- Casandra R. Newkirk
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
- Fisheries and Aquatic Sciences Program, School of Forest Resources and Conservation, University of Florida, Gainesville, FL, United States
| | - Thomas K. Frazer
- Fisheries and Aquatic Sciences Program, School of Forest Resources and Conservation, University of Florida, Gainesville, FL, United States
- School of Natural Resources and Environment, University of Florida, Gainesville, FL, United States
| | - Mark Q. Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
| | - Christine E. Schnitzler
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
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25
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Host and Symbiont Cell Cycle Coordination Is Mediated by Symbiotic State, Nutrition, and Partner Identity in a Model Cnidarian-Dinoflagellate Symbiosis. mBio 2020; 11:mBio.02626-19. [PMID: 32156819 PMCID: PMC7064764 DOI: 10.1128/mbio.02626-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biomass regulation is critical to the overall health of cnidarian-dinoflagellate symbioses. Despite the central role of the cell cycle in the growth and proliferation of cnidarian host cells and dinoflagellate symbionts, there are few studies that have examined the potential for host-symbiont coregulation. This study provides evidence for the acceleration of host cell proliferation when in local proximity to clusters of symbionts within cnidarian tentacles. The findings suggest that symbionts augment the cell cycle of not only their enveloping host cells but also neighboring cells in the epidermis and gastrodermis. This provides a possible mechanism for rapid colonization of cnidarian tissues. In addition, the cell cycles of symbionts differed depending on nutritional regime, symbiotic state, and species identity. The responses of cell cycle profiles to these different factors implicate a role for species-specific regulation of symbiont cell cycles within host cnidarian tissues. The cell cycle is a critical component of cellular proliferation, differentiation, and response to stress, yet its role in the regulation of intracellular symbioses is not well understood. To explore host-symbiont cell cycle coordination in a marine symbiosis, we employed a model for coral-dinoflagellate associations: the tropical sea anemone Aiptasia (Exaiptasia pallida) and its native microalgal photosymbionts (Breviolum minutum and Breviolum psygmophilum). Using fluorescent labeling and spatial point-pattern image analyses to characterize cell population distributions in both partners, we developed protocols that are tailored to the three-dimensional cellular landscape of a symbiotic sea anemone tentacle. Introducing cultured symbiont cells to symbiont-free adult hosts increased overall host cell proliferation rates. The acceleration occurred predominantly in the symbiont-containing gastrodermis near clusters of symbionts but was also observed in symbiont-free epidermal tissue layers, indicating that the presence of symbionts contributes to elevated proliferation rates in the entire host during colonization. Symbiont cell cycle progression differed between cultured algae and those residing within hosts; the endosymbiotic state resulted in increased S-phase but decreased G2/M-phase symbiont populations. These phenotypes and the deceleration of cell cycle progression varied with symbiont identity and host nutritional status. These results demonstrate that host and symbiont cells have substantial and species-specific effects on the proliferation rates of their mutualistic partners. This is the first empirical evidence to support species-specific regulation of the symbiont cell cycle within a single cnidarian-dinoflagellate association; similar regulatory mechanisms likely govern interpartner coordination in other coral-algal symbioses and shape their ecophysiological responses to a changing climate.
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26
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Bongrand C, Ruby EG. The impact of Vibrio fischeri strain variation on host colonization. Curr Opin Microbiol 2019; 50:15-19. [PMID: 31593868 DOI: 10.1016/j.mib.2019.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/17/2019] [Accepted: 09/02/2019] [Indexed: 01/06/2023]
Abstract
Strain-level epidemiology is a key approach to understanding the mechanisms underlying establishment of any host-microbe association. The squid-vibrio light organ symbiosis has proven to be an informative and tractable experimental model in which to discover these mechanisms because it involves only one bacterial species, Vibrio fischeri. In this horizontally transmitted symbiosis, the squid presents nutrients to the bacteria located in a bilobed light-emitting organ, while the symbionts provide bioluminescence to their host. To initiate this association, V. fischeri cells go through several distinct stages: from free-living in the bacterioplankton, to forming a multicellular aggregation near pores on the light organ's surface, to migrating through the pores and into crypts deep in the light organ, where the symbiont population grows and luminesces. Because individual cells must successfully navigate these distinct regions, phenotypic differences between strains will have a strong impact on the composition of the population finally colonizing the squid. Here we review recent advances in our understanding of behavioral characteristics that differentially drive a strain's success, including its effectiveness of aggregation, the rapidity with which it reaches the deep crypts, and its deployment of type VI secretion.
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