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Lamb AM, Peplow LM, Dungan AM, Ferguson SN, Harrison PL, Humphrey CA, McCutchan GA, Nitschke MR, van Oppen MJH. Interspecific hybridisation provides a low-risk option for increasing genetic diversity of reef-building corals. Biol Open 2024; 13:bio060482. [PMID: 39207257 PMCID: PMC11381923 DOI: 10.1242/bio.060482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 07/08/2024] [Indexed: 09/04/2024] Open
Abstract
Interspecific hybridisation increases genetic diversity and has played a significant role in the evolution of corals in the genus Acropora. In vitro fertilisation can be used to increase the frequency of hybridisation among corals, potentially enhancing their ability to adapt to climate change. Here, we assessed the field performance of hybrids derived from the highly cross-fertile coral species Acropora sarmentosa and Acropora florida from the Great Barrier Reef. Following outplanting to an inshore reef environment, the 10-month survivorship of the hybrid offspring groups was intermediate between that of the purebred groups, although not all pairwise comparisons were statistically significant. The A. florida purebreds, which had the lowest survivorship, were significantly larger at 10 months post-deployment compared to the other three groups. The four offspring groups harboured the same intracellular photosymbiont communities (Symbiodiniaceae), indicating that observed performance differences were due to the coral host and not photosymbiont communities. The limited differences in the performance of the groups and the lack of outbreeding depression of the F1 hybrids in the field suggest that interspecific hybridisation may be a useful method to boost the genetic diversity, and as such increase the adaptive capacity, of coral stock for restoration of degraded and potentially genetically eroded populations.
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Affiliation(s)
- Annika M Lamb
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
- School of Biosciences, The University of Melbourne, Grattan Street, Parkville VIC 3010
- AIMS@JCU - James Cook University, Townsville, QLD 4811, Australia
| | - Lesa M Peplow
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
| | - Ashley M Dungan
- School of Biosciences, The University of Melbourne, Grattan Street, Parkville VIC 3010
| | - Sophie N Ferguson
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
| | - Peter L Harrison
- Marine Ecology Research Centre - Southern Cross University, Lismore, NSW 2480
| | - Craig A Humphrey
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
| | - Guy A McCutchan
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
| | - Matthew R Nitschke
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
| | - Madeleine J H van Oppen
- Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland 4810, Queensland, Australia
- School of Biosciences, The University of Melbourne, Grattan Street, Parkville VIC 3010
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2
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MacVittie S, Doroodian S, Alberto A, Sogin M. Microbiome depletion and recovery in the sea anemone, Exaiptasia diaphana, following antibiotic exposure. mSystems 2024; 9:e0134223. [PMID: 38757963 PMCID: PMC11237641 DOI: 10.1128/msystems.01342-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 04/19/2024] [Indexed: 05/18/2024] Open
Abstract
Microbial species that comprise host-associated microbiomes play an essential role in maintaining and mediating the health of plants and animals. While defining the role of individual or even complex communities is important toward quantifying the effect of the microbiome on host health, it is often challenging to develop causal studies that link microbial populations to changes in host fitness. Here, we investigated the impacts of reduced microbial load following antibiotic exposure on the fitness of the anemone, Exaiptasia diaphana and subsequent recovery of the host's microbiome. Anemones were exposed to two different types of antibiotic solutions for 3 weeks and subsequently held in sterilized seawater for a 3-week recovery period. Our results revealed that both antibiotic treatments reduced the overall microbial load during and up to 1 week post-treatment. The observed reduction in microbial load was coupled with reduced anemone biomass, halted asexual reproduction rates, and for one of the antibiotic treatments, the partial removal of the anemone's algal symbiont. Finally, our amplicon sequencing results of the 16S rRNA gene revealed that anemone bacterial composition only shifted in treated individuals during the recovery phase of the experiment, where we also observed a significant reduction in the overall diversity of the microbial community. Our work implies that the E. diaphana's microbiome contributes to host fitness and that the recovery of the host's microbiome following disturbance with antibiotics leads to a reduced, but stable microbial state.IMPORTANCEExaiptasia diaphana is an emerging model used to define the cellular and molecular mechanisms of coral-algal symbioses. E. diaphana also houses a diverse microbiome, consisting of hundreds of microbial partners with undefined function. Here, we applied antibiotics to quantify the impact of microbiome removal on host fitness as well as define trajectories in microbiome recovery following disturbance. We showed that reduction of the microbiome leads to negative impacts on host fitness, and that the microbiome does not recover to its original composition while held under aseptic conditions. Rather the microbiome becomes less diverse, but more consistent across individuals. Our work is important because it suggests that anemone microbiomes play a role in maintaining host fitness, that they are susceptible to disturbance events, and that it is possible to generate gnotobiotic individuals that can be leveraged in microbiome manipulation studies to investigate the role of individual species on host health.
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Affiliation(s)
- Sophie MacVittie
- Department of Molecular Cell Biology, University of California, Merced, California, USA
| | - Saam Doroodian
- Department of Molecular Cell Biology, University of California, Merced, California, USA
| | - Aaron Alberto
- Department of Molecular Cell Biology, University of California, Merced, California, USA
| | - Maggie Sogin
- Department of Molecular Cell Biology, University of California, Merced, California, USA
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Maire J, Collingro A, Tandon K, Jameson VJ, Judd LM, Horn M, Blackall LL, van Oppen MJH. Chlamydiae as symbionts of photosynthetic dinoflagellates. THE ISME JOURNAL 2024; 18:wrae139. [PMID: 39046276 PMCID: PMC11317633 DOI: 10.1093/ismejo/wrae139] [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: 03/29/2024] [Revised: 06/13/2024] [Accepted: 07/23/2024] [Indexed: 07/25/2024]
Abstract
Chlamydiae are ubiquitous intracellular bacteria and infect a wide diversity of eukaryotes, including mammals. However, chlamydiae have never been reported to infect photosynthetic organisms. Here, we describe a novel chlamydial genus and species, Candidatus Algichlamydia australiensis, capable of infecting the photosynthetic dinoflagellate Cladocopium sp. (originally isolated from a scleractinian coral). Algichlamydia australiensis was confirmed to be intracellular by fluorescence in situ hybridization and confocal laser scanning microscopy and temporally stable at the population level by monitoring its relative abundance across four weeks of host growth. Using a combination of short- and long-read sequencing, we recovered a high-quality (completeness 91.73% and contamination 0.27%) metagenome-assembled genome of A. australiensis. Phylogenetic analyses show that this chlamydial taxon represents a new genus and species within the Simkaniaceae family. Algichlamydia australiensis possesses all the hallmark genes for chlamydiae-host interactions, including a complete type III secretion system. In addition, a type IV secretion system is encoded on a plasmid and has previously been observed for only three other chlamydial species. Twenty orthologous groups of genes are unique to A. australiensis, one of which is structurally similar to a protein known from Cyanobacteria and Archaeplastida involved in thylakoid biogenesis and maintenance, hinting at potential chlamydiae interactions with the chloroplasts of Cladocopium cells. Our study shows that chlamydiae infect dinoflagellate symbionts of cnidarians, the first photosynthetic organism reported to harbor chlamydiae, thereby expanding the breadth of chlamydial hosts and providing a new contribution to the discussion around the role of chlamydiae in the establishment of the primary plastid.
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Affiliation(s)
- Justin Maire
- School of Biosciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Kshitij Tandon
- School of Biosciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Vanta J Jameson
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute of Infection and Immunity, Parkville, VIC 3010, Australia
- Melbourne Cytometry Platform, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Louise M Judd
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, VIC 3010, Australia
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Linda L Blackall
- School of Biosciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - 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
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Maire J, Philip GK, Livingston J, Judd LM, Blackall LL, van Oppen MJH. Functional potential and evolutionary response to long-term heat selection of bacterial associates of coral photosymbionts. mSystems 2023; 8:e0086023. [PMID: 37909753 PMCID: PMC10746172 DOI: 10.1128/msystems.00860-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Symbiotic microorganisms are crucial for the survival of corals and their resistance to coral bleaching in the face of climate change. However, the impact of microbe-microbe interactions on coral functioning is mostly unknown but could be essential factors for coral adaption to future climates. Here, we investigated interactions between cultured dinoflagellates of the Symbiodiniaceae family, essential photosymbionts of corals, and associated bacteria. By assessing the genomic potential of 49 bacteria, we found that they are likely beneficial for Symbiodiniaceae, through the production of B vitamins and antioxidants. Additionally, bacterial genes involved in host-symbiont interactions, such as secretion systems, accumulated mutations following long-term exposure to heat, suggesting symbiotic interactions may change under climate change. This highlights the importance of microbe-microbe interactions in coral functioning.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Gayle K. Philip
- Melbourne Bioinformatics, The University of Melbourne, Parkville, Victoria, Australia
| | - Jadzia Livingston
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Louise M. Judd
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia
| | - Linda L. Blackall
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Madeleine J. H. van Oppen
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
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5
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Maire J, Deore P, Jameson VJ, Sakkas M, Perez-Gonzalez A, Blackall LL, van Oppen MJH. Assessing the contribution of bacteria to the heat tolerance of experimentally evolved coral photosymbionts. Environ Microbiol 2023; 25:3298-3318. [PMID: 37849020 DOI: 10.1111/1462-2920.16521] [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: 03/07/2023] [Accepted: 09/28/2023] [Indexed: 10/19/2023]
Abstract
Coral reefs are extremely vulnerable to ocean warming, which triggers coral bleaching-the loss of endosymbiotic microalgae (Symbiodiniaceae) from coral tissues, often leading to death. To enhance coral climate resilience, the symbiont, Cladocopium proliferum was experimentally evolved for >10 years under elevated temperatures resulting in increased heat tolerance. Bacterial 16S rRNA gene metabarcoding showed the composition of intra- and extracellular bacterial communities of heat-evolved strains was significantly different from that of wild-type strains, suggesting bacteria responded to elevated temperatures, and may even play a role in C. proliferum thermal tolerance. To assess whether microbiome transplantation could enhance heat tolerance of the sensitive wild-type C. proliferum, we transplanted bacterial communities from heat-evolved to the wild-type strain and subjected it to acute heat stress. Microbiome transplantation resulted in the incorporation of only 30 low-abundance strains into the microbiome of wild-type cultures, while the relative abundance of 14 pre-existing strains doubled in inoculated versus uninoculated samples. Inoculation with either wild-type or heat-evolved bacterial communities boosted C. proliferum growth, although no difference in heat tolerance was observed between the two inoculation treatments. This study provides evidence that Symbiodiniaceae-associated bacterial communities respond to heat selection and may contribute to coral adaptation to climate change.
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Affiliation(s)
- Justin Maire
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Pranali Deore
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Vanta J Jameson
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute of Infection and Immunity, Parkville, Victoria, Australia
- Melbourne Cytometry Platform, The University of Melbourne, Parkville, Victoria, Australia
| | - Magdaline Sakkas
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute of Infection and Immunity, Parkville, Victoria, Australia
- Melbourne Cytometry Platform, The University of Melbourne, Parkville, Victoria, Australia
| | - Alexis Perez-Gonzalez
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute of Infection and Immunity, Parkville, Victoria, Australia
- Melbourne Cytometry Platform, The University of Melbourne, Parkville, Victoria, Australia
| | - Linda L Blackall
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Madeleine J H van Oppen
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
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Maire J, Tandon K, Collingro A, van de Meene A, Damjanovic K, Gotze CR, Stephenson S, Philip GK, Horn M, Cantin NE, Blackall LL, van Oppen MJH. Colocalization and potential interactions of Endozoicomonas and chlamydiae in microbial aggregates of the coral Pocillopora acuta. SCIENCE ADVANCES 2023; 9:eadg0773. [PMID: 37196086 DOI: 10.1126/sciadv.adg0773] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/13/2023] [Indexed: 05/19/2023]
Abstract
Corals are associated with a variety of bacteria, which occur in the surface mucus layer, gastrovascular cavity, skeleton, and tissues. Some tissue-associated bacteria form clusters, termed cell-associated microbial aggregates (CAMAs), which are poorly studied. Here, we provide a comprehensive characterization of CAMAs in the coral Pocillopora acuta. Combining imaging techniques, laser capture microdissection, and amplicon and metagenome sequencing, we show that (i) CAMAs are located in the tentacle tips and may be intracellular; (ii) CAMAs contain Endozoicomonas (Gammaproteobacteria) and Simkania (Chlamydiota) bacteria; (iii) Endozoicomonas may provide vitamins to its host and use secretion systems and/or pili for colonization and aggregation; (iv) Endozoicomonas and Simkania occur in distinct, but adjacent, CAMAs; and (v) Simkania may receive acetate and heme from neighboring Endozoicomonas. Our study provides detailed insight into coral endosymbionts, thereby improving our understanding of coral physiology and health and providing important knowledge for coral reef conservation in the climate change era.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Kshitij Tandon
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Allison van de Meene
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Katarina Damjanovic
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Cecilie Ravn Gotze
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Sophie Stephenson
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Gayle K Philip
- Melbourne Bioinformatics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Neal E Cantin
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Linda L Blackall
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
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7
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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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