1
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Hoang KL, Salguero-Gómez R, Pike VL, King KC. The impacts of host association and perturbation on symbiont fitness. Symbiosis 2024; 92:439-451. [PMID: 38666134 PMCID: PMC11039428 DOI: 10.1007/s13199-024-00984-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 03/04/2024] [Indexed: 04/28/2024]
Abstract
Symbiosis can benefit hosts in numerous ways, but less is known about whether interactions with hosts benefit symbionts-the smaller species in the relationship. To determine the fitness impact of host association on symbionts in likely mutualisms, we conducted a meta-analysis across 91 unique host-symbiont pairings under a range of spatial and temporal contexts. Specifically, we assess the consequences to symbiont fitness when in and out of symbiosis, as well as when the symbiosis is under suboptimal or varying environments and biological conditions (e.g., host age). We find that some intracellular symbionts associated with protists tend to have greater fitness when the symbiosis is under stressful conditions. Symbionts of plants and animals did not exhibit this trend, suggesting that symbionts of multicellular hosts are more robust to perturbations. Symbiont fitness also generally increased with host age. Lastly, we show that symbionts able to proliferate in- and outside host cells exhibit greater fitness than those found exclusively inside or outside cells. The ability to grow in multiple locations may thus help symbionts thrive. We discuss these fitness patterns in light of host-driven factors, whereby hosts exert influence over symbionts to suit their own needs. Supplementary Information The online version contains supplementary material available at 10.1007/s13199-024-00984-6.
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Affiliation(s)
- Kim L. Hoang
- Department of Biology, University of Oxford, Oxford, UK
- Emory University School of Medicine, Atlanta, GA USA
| | | | | | - Kayla C. King
- Department of Biology, University of Oxford, Oxford, UK
- Department of Zoology, University of British Columbia, Vancouver, Canada
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, Canada
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2
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Brockhurst MA, Cameron DD, Beckerman AP. Fitness trade-offs and the origins of endosymbiosis. PLoS Biol 2024; 22:e3002580. [PMID: 38607979 PMCID: PMC11014431 DOI: 10.1371/journal.pbio.3002580] [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] [Indexed: 04/14/2024] Open
Abstract
Endosymbiosis drives evolutionary innovation and underpins the function of diverse ecosystems. The mechanistic origins of symbioses, however, remain unclear, in part because early evolutionary events are obscured by subsequent evolution and genetic drift. This Essay highlights how experimental studies of facultative, host-switched, and synthetic symbioses are revealing the important role of fitness trade-offs between within-host and free-living niches during the early-stage evolution of new symbiotic associations. The mutational targets underpinning such trade-offs are commonly regulatory genes, such that single mutations have major phenotypic effects on multiple traits, thus enabling and reinforcing the transition to a symbiotic lifestyle.
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Affiliation(s)
- Michael A. Brockhurst
- Division of Evolution, Infection and Genomics, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Duncan D. Cameron
- Department of Environmental and Earth Sciences, School of Natural Sciences, University of Manchester, Manchester, United Kingdom
| | - Andrew P. Beckerman
- School of Biosciences, Ecology and Evolutionary Biology, University of Sheffield, Sheffield, United Kingdom
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3
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Souza LS, Solowiej-Wedderburn J, Bonforti A, Libby E. Modeling endosymbioses: Insights and hypotheses from theoretical approaches. PLoS Biol 2024; 22:e3002583. [PMID: 38598454 PMCID: PMC11006130 DOI: 10.1371/journal.pbio.3002583] [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] [Indexed: 04/12/2024] Open
Abstract
Endosymbiotic relationships are pervasive across diverse taxa of life, offering key avenues for eco-evolutionary dynamics. Although a variety of experimental and empirical frameworks have shed light on critical aspects of endosymbiosis, theoretical frameworks (mathematical models) are especially well-suited for certain tasks. Mathematical models can integrate multiple factors to determine the net outcome of endosymbiotic relationships, identify broad patterns that connect endosymbioses with other systems, simplify biological complexity, generate hypotheses for underlying mechanisms, evaluate different hypotheses, identify constraints that limit certain biological interactions, and open new lines of inquiry. This Essay highlights the utility of mathematical models in endosymbiosis research, particularly in generating relevant hypotheses. Despite their limitations, mathematical models can be used to address known unknowns and discover unknown unknowns.
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Affiliation(s)
- Lucas Santana Souza
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, Sweden
- Integrated Science Lab, Umeå University, Umeå, Sweden
| | - Josephine Solowiej-Wedderburn
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, Sweden
- Integrated Science Lab, Umeå University, Umeå, Sweden
| | - Adriano Bonforti
- Integrated Science Lab, Umeå University, Umeå, Sweden
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
- Umeå Marine Sciences Centre, Umeå University, Norrbyn, Sweden
| | - Eric Libby
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, Sweden
- Integrated Science Lab, Umeå University, Umeå, Sweden
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4
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Noh S, Larson ER, Covitz RM, Chen A, Mazumder PR, Peck RF, Hamilton MC, Dettmann RA. Facultative symbiont virulence determines horizontal transmission rate without host strain specificity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528903. [PMID: 36824889 PMCID: PMC9949114 DOI: 10.1101/2023.02.16.528903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
In facultative symbioses, only a fraction of hosts are associated with a symbiont. Understanding why specific host and symbiont strains are associated can inform us of the evolutionary forces affecting facultative symbioses. Possibilities include ongoing host-symbiont coevolution driven by reciprocal selection, or priority effects that are neutral in respect to the host-symbiont interaction. We hypothesized that ongoing host-symbiont coevolution would lead to higher fitness estimates for naturally co-occurring (native) host and symbiont combinations compared to nonnative combinations. We used the Dictyostelium discoideum - Paraburkholderia bonniea system to test this hypothesis. P. bonniea features a reduced genome size relative to another Paraburkholderia symbiont of D. discoideum, indicating a significant history of coevolution with its host. Facultative symbionts may experience continued genome reduction if coevolution is ongoing, or their genome size may have reached a stable state if the symbiosis has also stabilized. Our work demonstrates that ongoing coevolution is unlikely for D. discoideum and P. bonniea. The system instead represents a stable facultative symbiosis. Specifically associated host and symbiont strains in this system are the result of priority effects, and presently unassociated hosts are simply uncolonized. We find evidence for a virulence-transmission trade-off without host strain specificity, and identify candidate virulence factors in the genomes of P. bonniea strains that may contribute to variation in benevolence.
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Affiliation(s)
- Suegene Noh
- Biology Department, Colby College, Waterville, Maine, USA
| | | | - Rachel M. Covitz
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Anna Chen
- Biology Department, Colby College, Waterville, Maine, USA
| | | | - Ron F. Peck
- Biology Department, Colby College, Waterville, Maine, USA
| | - Marisa C. Hamilton
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina, USA
| | - Robert A. Dettmann
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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5
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Horas EL, Metzger SM, Platzer B, Kelly JB, Becks L. Context-dependent costs and benefits of endosymbiotic interactions in a ciliate-algae system. Environ Microbiol 2022; 24:5924-5935. [PMID: 35799468 DOI: 10.1111/1462-2920.16112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Endosymbiosis, an interaction between two species where one lives within the other, has evolved multiple times independently, but the underlying mechanisms remain unclear. Evolutionary theory suggests that for an endosymbiotic interaction to remain stable over time, births of both partners should be higher than their deaths in symbiosis and deaths of both partners should be higher than their births when living independently. However, experimentally measuring this can be difficult and conclusions tend to focus on the host. Using a ciliate-algal system (Paramecium bursaria host and Chlorella endosymbionts), we estimated the benefits and costs of endosymbiosis for both organisms using fitness measurements in different biotic environments to test under which environmental conditions the net effects of the interaction were positive for both partners. We found that the net effects of harbouring endosymbionts were positive for the ciliate hosts as it allowed them to survive in conditions of low-quality bacteria food. The algae benefitted by being endosymbiotic when predators such as the hosts were present, but the net effects were dependent on the total density of hosts, decreasing as hosts densities increased. Overall, we show that including context-dependency of endosymbiosis is essential in understanding how these interactions have evolved.
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Affiliation(s)
- Elena L Horas
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Sarah M Metzger
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Barbara Platzer
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Joseph B Kelly
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Lutz Becks
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
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6
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Drew GC, Stevens EJ, King KC. Microbial evolution and transitions along the parasite-mutualist continuum. Nat Rev Microbiol 2021; 19:623-638. [PMID: 33875863 PMCID: PMC8054256 DOI: 10.1038/s41579-021-00550-7] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2021] [Indexed: 12/28/2022]
Abstract
Virtually all plants and animals, including humans, are home to symbiotic microorganisms. Symbiotic interactions can be neutral, harmful or have beneficial effects on the host organism. However, growing evidence suggests that microbial symbionts can evolve rapidly, resulting in drastic transitions along the parasite-mutualist continuum. In this Review, we integrate theoretical and empirical findings to discuss the mechanisms underpinning these evolutionary shifts, as well as the ecological drivers and why some host-microorganism interactions may be stuck at the end of the continuum. In addition to having biomedical consequences, understanding the dynamic life of microorganisms reveals how symbioses can shape an organism's biology and the entire community, particularly in a changing world.
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Affiliation(s)
| | | | - Kayla C King
- Department of Zoology, University of Oxford, Oxford, UK.
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7
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Drew GC, Budge GE, Frost CL, Neumann P, Siozios S, Yañez O, Hurst GDD. Transitions in symbiosis: evidence for environmental acquisition and social transmission within a clade of heritable symbionts. THE ISME JOURNAL 2021; 15:2956-2968. [PMID: 33941888 PMCID: PMC8443716 DOI: 10.1038/s41396-021-00977-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/17/2021] [Accepted: 04/06/2021] [Indexed: 02/03/2023]
Abstract
A dynamic continuum exists from free-living environmental microbes to strict host-associated symbionts that are vertically inherited. However, knowledge of the forces that drive transitions in symbiotic lifestyle and transmission mode is lacking. Arsenophonus is a diverse clade of bacterial symbionts, comprising reproductive parasites to coevolving obligate mutualists, in which the predominant mode of transmission is vertical. We describe a symbiosis between a member of the genus Arsenophonus and the Western honey bee. The symbiont shares common genomic and predicted metabolic properties with the male-killing symbiont Arsenophonus nasoniae, however we present multiple lines of evidence that the bee Arsenophonus deviates from a heritable model of transmission. Field sampling uncovered spatial and seasonal dynamics in symbiont prevalence, and rapid infection loss events were observed in field colonies and laboratory individuals. Fluorescent in situ hybridisation showed Arsenophonus localised in the gut, and detection was rare in screens of early honey bee life stages. We directly show horizontal transmission of Arsenophonus between bees under varying social conditions. We conclude that honey bees acquire Arsenophonus through a combination of environmental exposure and social contacts. These findings uncover a key link in the Arsenophonus clades trajectory from free-living ancestral life to obligate mutualism, and provide a foundation for studying transitions in symbiotic lifestyle.
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Affiliation(s)
- Georgia C Drew
- Department of Zoology, University of Oxford, Oxford, UK.
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
| | - Giles E Budge
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Crystal L Frost
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Stefanos Siozios
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Gregory D D Hurst
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
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8
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Symbiogenesis is driven through hierarchical reorganization of an ecosystem under closed or semi-closed conditions. Biosystems 2021; 205:104427. [PMID: 33857536 DOI: 10.1016/j.biosystems.2021.104427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/05/2021] [Accepted: 04/05/2021] [Indexed: 11/21/2022]
Abstract
Ecosystems generate selective environments and function as sources of various metabolic systems for symbiogenesis. In this study, we have explored how symbiogenesis occurs in the living world, from a holistic perspective, by observing a long-term experimental culture of an ecosystem model (CET microcosm) and using related findings in laboratory and field studies of endosymbiosis between auto- (photo-) and heterotrophic organisms. The results obtained suggest that symbiogenesis can occur in the mature stages of semi-closed ecosystems and lead to a new ecosystem-oriented perspective of symbiogenesis. Symbiogenesis is an aspect of ecosystem evolution in which whole ecosystem dynamics generate selective conditions operating on the component species, favoring symbiotic associations among some of them. The development of symbiotic associations then modifies the organization and material/energy flow structure of the ecosystem, which, in turn, modifies their selective environments.
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9
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Weiler J, Zilio G, Zeballos N, Nørgaard L, Conce Alberto WD, Krenek S, Kaltz O, Bright L. Among-Strain Variation in Resistance of Paramecium caudatum to the Endonuclear Parasite Holospora undulata: Geographic and Lineage-Specific Patterns. Front Microbiol 2020; 11:603046. [PMID: 33381098 PMCID: PMC7767928 DOI: 10.3389/fmicb.2020.603046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/24/2020] [Indexed: 01/04/2023] Open
Abstract
Resistance is a key determinant in interactions between hosts and their parasites. Understanding the amount and distribution of variation in this trait between strains can provide insights into (co)evolutionary processes and their potential to shape patterns of diversity in natural populations. Using controlled inoculation in experimental mass cultures, we investigated the quantitative variation in resistance to the bacterial parasite Holospora undulata across a worldwide collection of strains of its ciliate host Paramecium caudatum. We combined the observed variation with available information on the phylogeny and biogeography of the strains. We found substantial variation in resistance among strains, with upper-bound values of broad-sense heritability >0.5 (intraclass correlation coefficients). Strain estimates of resistance were repeatable between laboratories and ranged from total resistance to near-complete susceptibility. Early (1 week post inoculation) measurements provided higher estimates of resistance heritability than did later measurements (2-3 weeks), possibly due to diverging epidemiological dynamics in replicate cultures of the same strains. Genetic distance (based on a neutral marker) was positively correlated with the difference in resistance phenotype between strains (r = 0.45), essentially reflecting differences between highly divergent clades (haplogroups) within the host species. Haplogroup A strains, mostly European, were less resistant to the parasite (49% infection prevalence) than non-European haplogroup B strains (28%). At a smaller geographical scale (within Europe), strains that are geographically closer to the parasite origin (Southern Germany) were more susceptible to infection than those from further away. These patterns are consistent with a picture of local parasite adaptation. Our study demonstrates ample natural variation in resistance on which selection can act and hints at symbiont adaptation producing signatures in geographic and lineage-specific patterns of resistance in this model system.
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Affiliation(s)
- Jared Weiler
- Department of Biology, State University of New York, College at New Paltz, New Paltz, NY, United States
| | - Giacomo Zilio
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Nathalie Zeballos
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Louise Nørgaard
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne, VIC, Australia
| | - Winiffer D. Conce Alberto
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Sascha Krenek
- Institute of Hydrobiology, Technische Universität Dresden, Dresden, Germany
| | - Oliver Kaltz
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Lydia Bright
- Department of Biology, State University of New York, College at New Paltz, New Paltz, NY, United States
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10
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Stoy KS, Gibson AK, Gerardo NM, Morran LT. A need to consider the evolutionary genetics of host-symbiont mutualisms. J Evol Biol 2020; 33:1656-1668. [PMID: 33047414 DOI: 10.1111/jeb.13715] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/20/2020] [Accepted: 09/27/2020] [Indexed: 12/28/2022]
Abstract
Despite the ubiquity and importance of mutualistic interactions, we know little about the evolutionary genetics underlying their long-term persistence. As in antagonistic interactions, mutualistic symbioses are characterized by substantial levels of phenotypic and genetic diversity. In contrast to antagonistic interactions, however, we, by and large, do not understand how this variation arises, how it is maintained, nor its implications for future evolutionary change. Currently, we rely on phenotypic models to address the persistence of mutualistic symbioses, but the success of an interaction almost certainly depends heavily on genetic interactions. In this review, we argue that evolutionary genetic models could provide a framework for understanding the causes and consequences of diversity and why selection may favour processes that maintain variation in mutualistic interactions.
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Affiliation(s)
- Kayla S Stoy
- Department of Biology, Emory University, Atlanta, GA, USA.,Population Biology, Ecology, and Evolution Program, Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA
| | - Amanda K Gibson
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | | | - Levi T Morran
- Department of Biology, Emory University, Atlanta, GA, USA
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11
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Zachar I, Boza G. Endosymbiosis before eukaryotes: mitochondrial establishment in protoeukaryotes. Cell Mol Life Sci 2020; 77:3503-3523. [PMID: 32008087 PMCID: PMC7452879 DOI: 10.1007/s00018-020-03462-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 12/25/2019] [Accepted: 01/14/2020] [Indexed: 02/07/2023]
Abstract
Endosymbiosis and organellogenesis are virtually unknown among prokaryotes. The single presumed example is the endosymbiogenetic origin of mitochondria, which is hidden behind the event horizon of the last eukaryotic common ancestor. While eukaryotes are monophyletic, it is unlikely that during billions of years, there were no other prokaryote-prokaryote endosymbioses as symbiosis is extremely common among prokaryotes, e.g., in biofilms. Therefore, it is even more precarious to draw conclusions about potentially existing (or once existing) prokaryotic endosymbioses based on a single example. It is yet unknown if the bacterial endosymbiont was captured by a prokaryote or by a (proto-)eukaryote, and if the process of internalization was parasitic infection, slow engulfment, or phagocytosis. In this review, we accordingly explore multiple mechanisms and processes that could drive the evolution of unicellular microbial symbioses with a special attention to prokaryote-prokaryote interactions and to the mitochondrion, possibly the single prokaryotic endosymbiosis that turned out to be a major evolutionary transition. We investigate the ecology and evolutionary stability of inter-species microbial interactions based on dependence, physical proximity, cost-benefit budget, and the types of benefits, investments, and controls. We identify challenges that had to be conquered for the mitochondrial host to establish a stable eukaryotic lineage. Any assumption about the initial interaction of the mitochondrial ancestor and its contemporary host based solely on their modern relationship is rather perilous. As a result, we warn against assuming an initial mutually beneficial interaction based on modern mitochondria-host cooperation. This assumption is twice fallacious: (i) endosymbioses are known to evolve from exploitative interactions and (ii) cooperativity does not necessarily lead to stable mutualism. We point out that the lack of evidence so far on the evolution of endosymbiosis from mutual syntrophy supports the idea that mitochondria emerged from an exploitative (parasitic or phagotrophic) interaction rather than from syntrophy.
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Affiliation(s)
- István Zachar
- Evolutionary Systems Research Group, Institute of Evolution, Centre for Ecological Research, Klebelsberg Kunó str. 3., Tihany, 8237, Hungary.
- MTA-ELTE Theoretical Biology and Evolutionary Ecology Research Group, Department of Plant Taxonomy and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/c, Budapest, 1117, Hungary.
- Center for the Conceptual Foundations of Science, Parmenides Foundation, Kirchplatz 1, 82049, Munich, Germany.
| | - Gergely Boza
- Evolutionary Systems Research Group, Institute of Evolution, Centre for Ecological Research, Klebelsberg Kunó str. 3., Tihany, 8237, Hungary
- Evolution and Ecology Program, International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, 2361, Laxenburg, Austria
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12
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Chomicki G, Werner GDA, West SA, Kiers ET. Compartmentalization drives the evolution of symbiotic cooperation. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190602. [PMID: 32772665 DOI: 10.1098/rstb.2019.0602] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Across the tree of life, hosts have evolved mechanisms to control and mediate interactions with symbiotic partners. We suggest that the evolution of physical structures that allow hosts to spatially separate symbionts, termed compartmentalization, is a common mechanism used by hosts. Such compartmentalization allows hosts to: (i) isolate symbionts and control their reproduction; (ii) reward cooperative symbionts and punish or stop interactions with non-cooperative symbionts; and (iii) reduce direct conflict among different symbionts strains in a single host. Compartmentalization has allowed hosts to increase the benefits that they obtain from symbiotic partners across a diversity of interactions, including legumes and rhizobia, plants and fungi, squid and Vibrio, insects and nutrient provisioning bacteria, plants and insects, and the human microbiome. In cases where compartmentalization has not evolved, we ask why not. We argue that when partners interact in a competitive hierarchy, or when hosts engage in partnerships which are less costly, compartmentalization is less likely to evolve. We conclude that compartmentalization is key to understanding the evolution of symbiotic cooperation. This article is part of the theme issue 'The role of the microbiome in host evolution'.
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Affiliation(s)
- Guillaume Chomicki
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Gijsbert D A Werner
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford OX1 3SZ, UK.,Netherlands Scientific Council for Government Policy, Buitenhof 34, 2513 AH Den Haag, The Netherlands
| | - Stuart A West
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - E Toby Kiers
- Department of Ecological Science, VU University, Amsterdam, The Netherlands
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13
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Nguyen PL, van Baalen M. On the difficult evolutionary transition from the free-living lifestyle to obligate symbiosis. PLoS One 2020; 15:e0235811. [PMID: 32730262 PMCID: PMC7392539 DOI: 10.1371/journal.pone.0235811] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 06/23/2020] [Indexed: 12/17/2022] Open
Abstract
Obligate symbiosis evolved from free-living individuals most likely via the intermediate stage of facultative symbiosis. However, why should facultative symbionts, who can live independently but also benefit from their partners if these are available, give up this best of both worlds? Using the adaptive dynamics approach, we analyse a simple model, focusing on one partner of the symbiosis, to gain more insight into the selective forces that make individuals forgo the ability to reproduce in the free-living state. Our results suggest that, similar to the parasitism-mutualism continuum, the free-living way of life and obligate symbiosis are two extremes of a continuum of the ability to reproduce independently of a partner. More importantly, facultative symbiosis should be the rule as for many parameter combinations completely giving up independent reproduction or adopting a pure free-living strategy is not so easy. We also show that if host encounter comes at a cost, individuals that put more effort into increasing the chances to meet with their partners are more likely to give up the ability to reproduce independently. Finally, our model does not specify the ecological interactions between hosts and symbionts but we discuss briefly how the ecological nature of an interaction can influence the transition from facultative to obligate symbiosis.
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Affiliation(s)
| | - Minus van Baalen
- Institut de Biologie de l’École Normale Supérieur, Paris, France
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14
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Sørensen MES, Lowe CD, Minter EJA, Wood AJ, Cameron DD, Brockhurst MA. The role of exploitation in the establishment of mutualistic microbial symbioses. FEMS Microbiol Lett 2020; 366:5528313. [PMID: 31271421 PMCID: PMC6638607 DOI: 10.1093/femsle/fnz148] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/01/2019] [Indexed: 12/12/2022] Open
Abstract
Evolutionary theory suggests that the conditions required for the establishment of mutualistic symbioses through mutualism alone are highly restrictive, often requiring the evolution of complex stabilising mechanisms. Exploitation, whereby initially the host benefits at the expense of its symbiotic partner and mutual benefits evolve subsequently through trade-offs, offers an arguably simpler route to the establishment of mutualistic symbiosis. In this review, we discuss the theoretical and experimental evidence supporting a role for host exploitation in the establishment and evolution of mutualistic microbial symbioses, including data from both extant and experimentally evolved symbioses. We conclude that exploitation rather than mutualism may often explain the origin of mutualistic microbial symbioses.
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Affiliation(s)
- Megan E S Sørensen
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Chris D Lowe
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Ewan J A Minter
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - A Jamie Wood
- Department of Biology, University of York, York YO10 5DD, UK.,Department of Mathematics, University of York, York YO10 5DD, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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15
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High diversity and low host-specificity of Termitomyces symbionts cultivated by Microtermes spp. indicate frequent symbiont exchange. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2020.100917] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Levin SR, Gandon S, West SA. The social coevolution hypothesis for the origin of enzymatic cooperation. Nat Ecol Evol 2019; 4:132-137. [PMID: 31844190 DOI: 10.1038/s41559-019-1039-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 10/15/2019] [Indexed: 11/09/2022]
Abstract
At the start of life, the origin of a primitive genome required individual replicators, or genes, to act like enzymes and cooperatively copy each other. The evolutionary stability of such enzymatic cooperation poses a problem, because it would have been susceptible to parasitic replicators that did not act like enzymes but could still benefit from the enzymatic behaviour of other replicators. Existing hypotheses to solve this problem require restrictive assumptions that may not be justified, such as the evolution of a cell membrane before the evolution of enzymatic cooperation. We show theoretically that, instead, selection itself can lead to replicators grouping themselves together in a way that favours cooperation. We show that the tendency to physically associate with others and cooperative enzymatic activity can coevolve, leading to the evolution of physically linked cooperative replicators. Our results shift the empirical problem from a search for special environmental conditions to questions about what types of phenotypes can be produced by simple replicators.
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Affiliation(s)
- Samuel R Levin
- Department of Zoology, University of Oxford, Oxford, UK.
| | - Sylvain Gandon
- CEFE UMR 5175, CNRS, Université de Montpellier, Montpellier, France
| | - Stuart A West
- Department of Zoology, University of Oxford, Oxford, UK
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17
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Fan Y, Xiao Y, Momeni B, Liu YY. Horizontal gene transfer can help maintain the equilibrium of microbial communities. J Theor Biol 2018; 454:53-59. [DOI: 10.1016/j.jtbi.2018.05.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 01/15/2023]
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Gerardo N, Hurst G. Q&A: Friends (but sometimes foes) within: the complex evolutionary ecology of symbioses between host and microbes. BMC Biol 2017; 15:126. [PMID: 29282064 PMCID: PMC5744397 DOI: 10.1186/s12915-017-0455-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Over the past decade, there has been a pronounced shift in the study of host-microbe associations, with recognition that many of these associations are beneficial, and often critical, for a diverse array of hosts. There may also be pronounced benefits for the microbes, though this is less well empirically understood. Significant progress has been made in understanding how ecology and evolution shape simple associations between hosts and one or a few microbial species, and this work can serve as a foundation to study the ecology and evolution of host associations with their often complex microbial communities (microbiomes).
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Affiliation(s)
- Nicole Gerardo
- Department of Biology, Emory University, 1510 Clifton RD, Atlanta, Georgia, 30322, USA.
| | - Gregory Hurst
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
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Dean AD, Minter EJA, Sørensen MES, Lowe CD, Cameron DD, Brockhurst MA, Jamie Wood A. Host control and nutrient trading in a photosynthetic symbiosis. J Theor Biol 2016; 405:82-93. [PMID: 26925812 DOI: 10.1016/j.jtbi.2016.02.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 11/25/2022]
Abstract
Photosymbiosis is one of the most important evolutionary trajectories, resulting in the chloroplast and the subsequent development of all complex photosynthetic organisms. The ciliate Paramecium bursaria and the alga Chlorella have a well established and well studied light dependent endosymbiotic relationship. Despite its prominence, there remain many unanswered questions regarding the exact mechanisms of the photosymbiosis. Of particular interest is how a host maintains and manages its symbiont load in response to the allocation of nutrients between itself and its symbionts. Here we construct a detailed mathematical model, parameterised from the literature, that explicitly incorporates nutrient trading within a deterministic model of both partners. The model demonstrates how the symbiotic relationship can manifest as parasitism of the host by the symbionts, mutualism, wherein both partners benefit, or exploitation of the symbionts by the hosts. We show that the precise nature of the photosymbiosis is determined by both environmental conditions (how much light is available for photosynthesis) and the level of control a host has over its symbiont load. Our model provides a framework within which it is possible to pose detailed questions regarding the evolutionary behaviour of this important example of an established light dependent endosymbiosis; we focus on one question in particular, namely the evolution of host control, and show using an adaptive dynamics approach that a moderate level of host control may evolve provided the associated costs are not prohibitive.
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Affiliation(s)
- Andrew D Dean
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; Department of Mathematics, University of York, York YO10 5DD, UK.
| | - Ewan J A Minter
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Megan E S Sørensen
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Christopher D Lowe
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Treliever Road, Penryn TR10 9FE, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK
| | | | - A Jamie Wood
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; Department of Mathematics, University of York, York YO10 5DD, UK
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Lowe C, Minter E, Cameron D, Brockhurst M. Shining a Light on Exploitative Host Control in a Photosynthetic Endosymbiosis. Curr Biol 2016; 26:207-211. [DOI: 10.1016/j.cub.2015.11.052] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/27/2015] [Accepted: 11/12/2015] [Indexed: 10/22/2022]
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21
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Antonovics J, Bergmann J, Hempel S, Verbruggen E, Veresoglou S, Rillig M. The evolution of mutualism from reciprocal parasitism: more ecological clothes for the Prisoner’s Dilemma. Evol Ecol 2015. [DOI: 10.1007/s10682-015-9775-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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23
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Fukui S. Evolution of symbiosis with resource allocation from fecundity to survival. Naturwissenschaften 2014; 101:437-46. [PMID: 24744057 PMCID: PMC4012156 DOI: 10.1007/s00114-014-1175-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 04/05/2014] [Accepted: 04/06/2014] [Indexed: 11/30/2022]
Abstract
Symbiosis is one of the most fundamental relationships between or among organisms and includes parasitism (which has negative effects on the fitness of the interacting partner), commensalism (no effect), and mutualism (positive effects). The effects of these interactions are usually assumed to influence a single component of a species’ fitness, either survival or fecundity, even though in reality the interaction can simultaneously affect both of these components. I used a dual lattice model to investigate the process of evolution of mutualistic symbiosis in the presence of interactive effects on both survival and fecundity. I demonstrate that a positive effect on survival and a negative effect on fecundity are key to the establishment of mutualism. Furthermore, both the parasitic and the mutualistic behaviour must carry large costs for mutualism to evolve. This helps develop a new understanding of symbiosis as a function of resource allocation, in which resources are shifted from fecundity to survival. The simultaneous establishment of mutualism from parasitism never occurs in two species, but can do so in one of the species as long as the partner still behaves parasitically. This suggests that one of the altruistic behaviours in a mutualistic unit consisting of two species must originate as a parasitic behaviour.
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Affiliation(s)
- Shin Fukui
- Center for Ecological Research, Kyoto University, 2-509-3 Hirano, Otsu, Shiga, 520-2113, Japan,
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24
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Zug R, Hammerstein P. Bad guys turned nice? A critical assessment of Wolbachia mutualisms in arthropod hosts. Biol Rev Camb Philos Soc 2014; 90:89-111. [PMID: 24618033 DOI: 10.1111/brv.12098] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 12/21/2022]
Abstract
Wolbachia are the most abundant bacterial endosymbionts among arthropods. Although maternally inherited, they do not conform to the widespread view that vertical transmission inevitably selects for beneficial symbionts. Instead, Wolbachia are notorious for their reproductive parasitism which, although lowering host fitness, ensures their spread. However, even for reproductive parasites it can pay to enhance host fitness. Indeed, there is a recent upsurge of reports on Wolbachia-associated fitness benefits. Therefore, the question arises how such instances of mutualism are related to the phenotypes of reproductive parasitism. Here, we review the evidence of Wolbachia mutualisms in arthropods, including both facultative and obligate relationships, and critically assess their biological relevance. Although many studies report anti-pathogenic effects of Wolbachia, few actually prove these effects to be relevant to field conditions. We further show that Wolbachia frequently have beneficial and detrimental effects at the same time, and that reproductive manipulations and obligate mutualisms may share common mechanisms. These findings undermine the idea of a clear-cut distinction between Wolbachia mutualism and parasitism. In general, both facultative and obligate mutualisms can have a strong, and sometimes unforeseen, impact on the ecology and evolution of Wolbachia and their arthropod hosts. Acknowledging this mutualistic potential might be the key to a better understanding of some unresolved issues in the study of Wolbachia-host interactions.
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Affiliation(s)
- Roman Zug
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115, Berlin, Germany
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25
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Nakajima T, Matsubara T, Ohta Y, Miyake D. Exploitation or cooperation? Evolution of a host (ciliate)-benefiting alga in a long-term experimental microcosm culture. Biosystems 2013; 113:127-39. [DOI: 10.1016/j.biosystems.2013.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 11/29/2022]
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26
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Ezoe H, Ikegawa Y. Coexistence of mutualists and non-mutualists in a dual-lattice model. J Theor Biol 2013; 332:1-8. [PMID: 23614874 DOI: 10.1016/j.jtbi.2013.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/12/2013] [Accepted: 04/13/2013] [Indexed: 11/26/2022]
Abstract
Evolution and maintenance of mutualism have been one of the major questions in evolutionary ecology, because it is often susceptible of invasion of non-mutualistic strategy. Some previous studies using dual-lattice model suggest that spatial structures of habitat can prevent non-mutualism from prevailing over mutualism, while the detail of the dynamics is not fully revealed. Here we explore population dynamics of the two strategies (mutualism and non-mutualism) in two species engaged in Prisoner's Dilemma game on a dual-lattice space, especially focusing on whether mutualists and non-mutualists can coexist in long-term dynamics. The habitat consists of two layers, each of which a population of species inhabits, and interspecific interaction is restricted between two corresponding sites of the layers. Each individual of the both species is either a mutualist or a non-mutualist and only the former pay cost c for benefit of the partner b. The payoff of the game affects the individuals' fecundity, while the mortality is constant. Reproduction is restricted to neighboring vacant sites of the focal individuals. Our computer simulations of the model show that even if b/c ratio remains constant, mutualists become dominant in both species over wider ranges of basic reproduction rate (reproduction rate without interspecific interaction) as b and c increase. If basic reproduction rates are asymmetric between the species or basic reproduction rates were sufficiently large, mutualists and non-mutualists can coexist in one or both species, while their population sizes often fluctuate. Transition of the final state between mutualism and non-mutualism happens rather discontinuously, then total population sizes change drastically at the transition. Moreover, we also find paradoxical cases of unilateral exploitation, i.e. one species consists of mutualists and other species non-mutualists. Additional simulations reveal that accidental extinction of the non-mutualists of one species can result in extinction of mutualist of the other species.
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Affiliation(s)
- Hideo Ezoe
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai 599-8531, Japan.
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27
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Mondo SJ, Toomer KH, Morton JB, Lekberg Y, Pawlowska TE. EVOLUTIONARY STABILITY IN A 400-MILLION-YEAR-OLD HERITABLE FACULTATIVE MUTUALISM. Evolution 2012; 66:2564-76. [DOI: 10.1111/j.1558-5646.2012.01611.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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28
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Abstract
Mutualistic microbial symbioses are one of the key innovations in the evolution of biological diversity, enabling the expansion of species' niches and the production of sophisticated structures such as the eukaryotic cell. For some of the best-studied cases, we are beginning to have network models of symbiotic metabolism, but this work is in its infancy and has not been developed with an evolutionary perspective. However, theoreticians have long been interested in how these symbioses arise and persist and have applied modelling approaches from economics, evolution, ecology, and sociobology to a number of fundamental questions. We provide an overview of these questions, followed by specific modelling examples. We cover economic game theory, including the Prisoner's Dilemma, the Snowdrift game, and biological markets. We also describe the eco-evolutionary framework of adaptive dynamics, inclusive fitness, and population genetic models. We aim to provide insight into the strengths and weaknesses of each approach and into how current evolutionary methods can benefit an understanding of the mechanistic basis of host-symbiont interactions elucidated by molecular network models.
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Affiliation(s)
- Maren L Friesen
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA.
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29
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Carval D, Ferriere R. A unified model for the coevolution of resistance, tolerance, and virulence. Evolution 2010; 64:2988-3009. [PMID: 20497218 DOI: 10.1111/j.1558-5646.2010.01035.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We present a general host-parasite model that unifies previous theory by investigating the coevolution of virulence, resistance, and tolerance, with respect to multiple physiological, epidemiological, and environmental parameters. Four sets of new predictions emerge. First, compared to virulence coevolving with resistance or tolerance, three-trait coevolution promotes more virulence and less tolerance, and broadens conditions under which pure defenses evolve. Second, the cost and efficiency of virulence and the epidemiological rates are the key factors of virulence coevolving with resistance and tolerance. Maximum virulence evolves for intermediate infection rate, at which coevolved levels of resistance and tolerance are both high. The influence of host and parasite background mortalities is strong on the evolution of defenses and weak on the coevolution of virulence. Third, evolutionary correlations between defenses can switch sign along single-parameter gradients. The evolutionary trade-off between resistance and tolerance may coevolve with virulence that either increases or decreases monotonically, depending on the underlying parameter gradient. Fourth, despite global attractiveness and stability of coevolutionary equilibria, not-so-rare and not-so-small mutations can beget large variation in virulence and defenses around equilibrium, in the form of transient "evolutionary spikes." Implications for evolutionary management of infections are discussed and directions for future research are outlined.
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Affiliation(s)
- Dominique Carval
- Laboratoire Ecologie & Evolution, CNRS UMR 7625, Université Paris 6, 7 quai Saint-Bernard, Paris Cedex 05, France.
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30
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Ezoe H. Dual lattice model of the evolution of facultative symbiosis with continuous Prisoner's Dilemma game. J Theor Biol 2009; 259:744-50. [PMID: 19409909 DOI: 10.1016/j.jtbi.2009.04.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 04/23/2009] [Accepted: 04/23/2009] [Indexed: 10/20/2022]
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31
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Abstract
We propose that microbes that have developed persistent relationships with human hosts have evolved cross-signalling mechanisms that permit homeostasis that conforms to Nash equilibria and, more specifically, to evolutionarily stable strategies. This implies that a group of highly diverse organisms has evolved within the changing contexts of variation in effective human population size and lifespan, shaping the equilibria achieved, and creating relationships resembling climax communities. We propose that such ecosystems contain nested communities in which equilibrium at one level contributes to homeostasis at another. The model can aid prediction of equilibrium states in the context of further change: widespread immunodeficiency, changing population densities, or extinctions.
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Clay K, Holah J, Rudgers JA. Herbivores cause a rapid increase in hereditary symbiosis and alter plant community composition. Proc Natl Acad Sci U S A 2005; 102:12465-70. [PMID: 16116093 PMCID: PMC1194913 DOI: 10.1073/pnas.0503059102] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Indexed: 11/18/2022] Open
Abstract
Microbial symbioses are ubiquitous in nature. Hereditary symbionts warrant particular attention because of their direct effects on the evolutionary potential of their hosts. In plants, hereditary fungal endophytes can increase the competitive ability, drought tolerance, and herbivore resistance of their host, although it is unclear whether or how these ecological benefits may alter the dynamics of the endophyte symbiosis over time. Here, we demonstrate that herbivores alter the dynamics of a hereditary symbiont under field conditions. Also, we show that changes in symbiont frequency were accompanied by shifts in the overall structure of the plant community. Replicated 25-m2 plots were enriched with seed of the introduced grass, Lolium arundinaceum at an initial frequency of 50% infection by the systemic, seed-transmitted endophyte Neotyphodium coenophialum. Over 54 months, there was a significantly greater increase in endophyte-infection frequency in the presence of herbivores (30% increase) than where mammalian and insect herbivory were experimentally reduced by fencing and insecticide application (12% increase). Under ambient mammalian herbivory, the above-ground biomass of nonhost plant species was reduced compared with the mammal-exclusion treatment, and plant composition shifted toward greater relative biomass of infected, tall fescue grass. These results demonstrate that herbivores can drive plant-microbe dynamics and, in doing so, modify plant community structure directly and indirectly.
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Affiliation(s)
- Keith Clay
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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de Vries EJ, Jacobs G, Sabelis MW, Menken SBJ, Breeuwer JAJ. Diet-dependent effects of gut bacteria on their insect host: the symbiosis of Erwinia sp. and western flower thrips. Proc Biol Sci 2004; 271:2171-8. [PMID: 15475338 PMCID: PMC1691834 DOI: 10.1098/rspb.2004.2817] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies on bacteria in the gut of insect species are numerous, but their focus is hardly ever on the impact on host performance. We showed earlier that Erwinia bacteria occur in the gut of western flower thrips, most probably acquired during feeding. Here, we investigate whether thrips gain a net benefit or pay a net cost because of these gut bacteria. On a diet of cucumber leaves, the time to maturity is shorter and the oviposition rate is higher in thrips with bacteria than in thrips without (aposymbionts). When fed on cucumber leaves and pollen, aposymbionts develop faster and lay more eggs. So Erwinia bacteria benefit or parasitize their thrips hosts depending on the diet, which is in accordance with theoretical predictions for fitness of organisms engaged in symbiotic interactions. Possibly, the transmission of gut bacteria has not become strictly vertical because of this diet-dependent fitness variability.
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Affiliation(s)
- Egbert J de Vries
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
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34
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Egger KN, Hibbett DS. The evolutionary implications of exploitation in mycorrhizas. ACTA ACUST UNITED AC 2004. [DOI: 10.1139/b04-056] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Some views of mutualism, where the fitness of two symbiotic partners is higher in association than when apart, assume that they necessarily evolve towards greater benefit for the partners. Most mutualisms, however, seem prone to conflicts of interest that destabilize the partnership. These conflicts arise in part because mutualistic outcomes are conditional, depending upon complex interactions between environmental, developmental, and genotypic factors. Mutualisms are also subject to exploitation or cheating. Although various compensating mechanisms have been proposed to explain how mutualism can be maintained in the presence of exploiters, none of these mechanisms can eliminate exploitation. In this paper we explore various compensating mechanisms in mycorrhizas, examine the evidence for exploitation in mycorrhizas, and conclude that mycorrhizal mutualisms exhibit characteristics that are more consistent with a concept of reciprocal parasitism. We propose that researchers should not assume mycorrhizas are mutualistic based upon structural characteristics or limited functional studies showing bilateral exchange and should view mycorrhizas as occupying a wider range on the symbiotic continuum, including commensalism and antagonism. We recommend that comparative studies of mycorrhizas incorporate other types of root associations that have traditionally been considered antagonistic.Key words: mycorrhizas, mutualism, exploiters, compensating mechanisms, symbiotic continuum.
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Vala F, Van Opijnen T, Breeuwer JAJ, Sabelis MW. Genetic conflicts over sex ratio: mite-endosymbiont interactions. Am Nat 2003; 161:254-66. [PMID: 12675371 DOI: 10.1086/345856] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nucleocytoplasmic genetic conflicts arise as a result of asymmetric transmission of cytoplasmic and nuclear genes. Spread of a cytoplasmic element promoting female-biased sex ratios creates selection on nuclear genes for mechanisms that decrease the bias. Here we investigate the conflict over sex ratio between the cytoplasmic bacterium Wolbachia and the two-spotted spider mite Tetranychus urticae Koch. We show that, first, infected females produce significantly more female-biased sex ratios than uninfected (cured) females. Second, this effect is not due to parthenogenesis, male killing, or feminization, phenotypes commonly associated with infection by Wolbachia. Third, sex ratio is a trait with a heritable component in this species; thus, it can evolve under selection. Fourth, the sex ratio produced by uninfected (cured) females changes over time, approaching the sex ratio produced by females from the infected culture. On the basis of these results, we suggest that after sex ratio manipulation by Wolbachia, a host compensatory mechanism evolved that allows infected females to produce the sex ratio favored by nuclear genes. We discuss the evolution of "mutualism" with respect to the evolution of host mechanisms that compensate for effects induced by vertically transmitted "parasites."
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Affiliation(s)
- Filipa Vala
- Institute for Biodiversity and Ecosystem Dynamics, Section of Population Biology, University of Amsterdam, P.O. Box 94084, Amsterdam 1090 GB, The Netherlands.
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Ferriere R, Bronstein JL, Rinaldi S, Law R, Gauduchon M. Cheating and the evolutionary stability of mutualisms. Proc Biol Sci 2002; 269:773-80. [PMID: 11958708 PMCID: PMC1690960 DOI: 10.1098/rspb.2001.1900] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Interspecific mutualisms have been playing a central role in the functioning of all ecosystems since the early history of life. Yet the theory of coevolution of mutualists is virtually nonexistent, by contrast with well-developed coevolutionary theories of competition, predator-prey and host-parasite interactions. This has prevented resolution of a basic puzzle posed by mutualisms: their persistence in spite of apparent evolutionary instability. The selective advantage of 'cheating', that is, reaping mutualistic benefits while providing fewer commodities to the partner species, is commonly believed to erode a mutualistic interaction, leading to its dissolution or reciprocal extinction. However, recent empirical findings indicate that stable associations of mutualists and cheaters have existed over long evolutionary periods. Here, we show that asymmetrical competition within species for the commodities offered by mutualistic partners provides a simple and testable ecological mechanism that can account for the long-term persistence of mutualisms. Cheating, in effect, establishes a background against which better mutualists can display any competitive superiority. This can lead to the coexistence and divergence of mutualist and cheater phenotypes, as well as to the coexistence of ecologically similar, but unrelated mutualists and cheaters.
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Affiliation(s)
- Régis Ferriere
- Unit of Mathematical Eco-Evolutionary Biology, Laboratoire d'Ecologie, Ecole Normale Supeérieure, 46 rue d'Ulm, 75230 Paris cedex 05, France.
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Meszéna G, Kisdi É, Dieckmann U, Geritz SAH, Metz JAJ. Evolutionary Optimisation Models and Matrix Games in the Unified Perspective of Adaptive Dynamics. ACTA ACUST UNITED AC 2002. [DOI: 10.1556/select.2.2001.1-2.14] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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38
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de Mazancourt C, Loreau M, Dieckmann U. Can the Evolution of Plant Defense Lead to Plant‐Herbivore Mutualism? Am Nat 2001; 158:109-23. [DOI: 10.1086/321306] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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39
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Hochberg, Gomulkiewicz, Holt, Thompson. Weak sinks could cradle mutualistic symbioses - strong sources should harbour parasitic symbioses. J Evol Biol 2000. [DOI: 10.1046/j.1420-9101.2000.00157.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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