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Kulkarni M, Naik NV, Borges RM. Who holds the reins? Context-dependent resource allocation in the mutualism between fig trees and their fig wasp pollinators. Oecologia 2024; 205:215-227. [PMID: 38801540 DOI: 10.1007/s00442-024-05566-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Mutualisms are consumer-resource interactions, in which goods and services are exchanged. Biological market theory states that exchanges should be regulated by both partners. However, most studies on mutualisms are one-sided, focusing on the control exercised by host organisms on their symbionts. In the brood-site pollination mutualism between fig trees and their symbiont wasp pollinators, galled flowers are development sites for pollinator larvae and are exchanged for pollination services. We determined if pollinator galls influenced resource allocation to fig inflorescences called syconia and considered feedbacks from the host tree. We experimentally produced syconia containing only seeds (S), only pollinator galls (G) or seeds and galls (SG) with varying number of introduced female pollinator wasps, i.e., foundress wasps. Biomass allocation to syconia was affected by foundress numbers and treatment groups; SG treatments received highest biomass allocation at low foundress numbers, and both G and SG treatments at high foundress numbers. Seeds are important determinants of allocation at low foundress numbers; galls are likely more influential at high foundress numbers. Most allocation in the G and SG treatment was to the syconium wall, likely as protection from parasitoids and temperature/humidity fluctuations. Dry mass of individual seeds and wasps (except at low foundress numbers) was unchanged between treatment groups, indicating seeds and wasps regulate resource flow into them, with lower flow into galls containing the smaller males compared to females commensurate with sexual dimorphism. We demonstrate the importance of considering the direct role of symbionts in accessing resources and controlling exchanges within mutualisms.
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Affiliation(s)
- Manasa Kulkarni
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, 560012, India
| | - Nehal Vijay Naik
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, 560012, India
- Department of Biology (Ecology and Evolutionary Biology), University of Toronto Mississauga, Mississauga, ON, Canada
| | - Renee M Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, 560012, India.
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2
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Martignoni MM, Tyson RC, Kolodny O, Garnier J. Mutualism at the leading edge: insights into the eco-evolutionary dynamics of host-symbiont communities during range expansion. J Math Biol 2024; 88:24. [PMID: 38308102 DOI: 10.1007/s00285-023-02037-w] [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: 04/09/2023] [Revised: 09/04/2023] [Accepted: 12/14/2023] [Indexed: 02/04/2024]
Abstract
The evolution of mutualism between host and symbiont communities plays an essential role in maintaining ecosystem function and should therefore have a profound effect on their range expansion dynamics. In particular, the presence of mutualistic symbionts at the leading edge of a host-symbiont community should enhance its propagation in space. We develop a theoretical framework that captures the eco-evolutionary dynamics of host-symbiont communities, to investigate how the evolution of resource exchange may shape community structure during range expansion. We consider a community with symbionts that are mutualistic or parasitic to various degrees, where parasitic symbionts receive the same amount of resource from the host as mutualistic symbionts, but at a lower cost. The selective advantage of parasitic symbionts over mutualistic ones is increased with resource availability (i.e. with host density), promoting mutualism at the range edges, where host density is low, and parasitism at the population core, where host density is higher. This spatial selection also influences the speed of spread. We find that the host growth rate (which depends on the average benefit provided by the symbionts) is maximal at the range edges, where symbionts are more mutualistic, and that host-symbiont communities with high symbiont density at their core (e.g. resulting from more mutualistic hosts) spread faster into new territories. These results indicate that the expansion of host-symbiont communities is pulled by the hosts but pushed by the symbionts, in a unique push-pull dynamic where both the host and symbionts are active and tightly-linked players.
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Affiliation(s)
- Maria M Martignoni
- Department of Ecology, Evolution and Behavior, A. Silberman Institute of Life Sciences, Faculty of Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Rebecca C Tyson
- CMPS Department (Mathematics), University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Oren Kolodny
- Department of Ecology, Evolution and Behavior, A. Silberman Institute of Life Sciences, Faculty of Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jimmy Garnier
- Laboratory of Mathematics, CNRS, Université Savoie-Mont Blanc, Université Grenoble Alpes, Chambery, France
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3
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Travers-Cook TJ, Jokela J, Buser CC. The evolutionary ecology of fungal killer phenotypes. Proc Biol Sci 2023; 290:20231108. [PMID: 37583325 PMCID: PMC10427833 DOI: 10.1098/rspb.2023.1108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/20/2023] [Indexed: 08/17/2023] Open
Abstract
Ecological interactions influence evolutionary dynamics by selecting upon fitness variation within species. Antagonistic interactions often promote genetic and species diversity, despite the inherently suppressive effect they can have on the species experiencing them. A central aim of evolutionary ecology is to understand how diversity is maintained in systems experiencing antagonism. In this review, we address how certain single-celled and dimorphic fungi have evolved allelopathic killer phenotypes that engage in antagonistic interactions. We discuss the evolutionary pathways to the production of lethal toxins, the functions of killer phenotypes and the consequences of competition for toxin producers, their competitors and toxin-encoding endosymbionts. Killer phenotypes are powerful models because many appear to have evolved independently, enabling across-phylogeny comparisons of the origins, functions and consequences of allelopathic antagonism. Killer phenotypes can eliminate host competitors and influence evolutionary dynamics, yet the evolutionary ecology of killer phenotypes remains largely unknown. We discuss what is known and what remains to be ascertained about killer phenotype ecology and evolution, while bringing their model system properties to the reader's attention.
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Affiliation(s)
- Thomas J. Travers-Cook
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Department of Aquatic Ecology, Eawag, Dübendorf, Switzerland
| | - Jukka Jokela
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Department of Aquatic Ecology, Eawag, Dübendorf, Switzerland
| | - Claudia C. Buser
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Department of Aquatic Ecology, Eawag, Dübendorf, Switzerland
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4
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Quides KW, Lee Y, Hur T, Atamian HS. Evaluation of qPCR to Detect Shifts in Population Composition of the Rhizobial Symbiont Mesorhizobium japonicum during Serial in Planta Transfers. BIOLOGY 2023; 12:biology12020277. [PMID: 36829553 PMCID: PMC9953586 DOI: 10.3390/biology12020277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/12/2023]
Abstract
Microbial symbionts range from mutualistic to commensal to antagonistic. While these roles are distinct in their outcome, they are also fluid in a changing environment. Here, we used the Lotus japonicus-Mesorhizobium japonicum symbiosis to investigate short-term and long-term shifts in population abundance using an effective, fast, and low-cost tracking methodology for M. japonicum. We use quantitative polymerase chain reaction (qPCR) to track previously generated signature-tagged M. japonicum mutants targeting the Tn5 transposon insertion and the flanking gene. We used a highly beneficial wild type and moderately beneficial and non-beneficial mutants of M. japonicum sp. nov. to demonstrate the specificity of these primers to estimate the relative abundance of each genotype within individual nodules and after serial transfers to new hosts. For the moderate and non-beneficial genotypes, qPCR allowed us to differentiate genotypes that are phenotypically indistinguishable and investigate host control with suboptimal symbionts. We consistently found the wild type increasing in the proportion of the population, but our data suggest a potential reproductive trade-off between the moderate and non-beneficial genotypes. The multi-generation framework we used, coupled with qPCR, can easily be scaled up to track dozens of M. japonicum mutants simultaneously. Moreover, these mutants can be used to explore M. japonicum genotype abundance in the presence of a complex soil community.
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Affiliation(s)
- Kenjiro W. Quides
- Biological Sciences Program, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Yoobeen Lee
- Biological Sciences Program, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
| | - Teresa Hur
- Biological Sciences Program, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
| | - Hagop S. Atamian
- Biological Sciences Program, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
- Correspondence:
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5
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Montoya AP, Wendlandt CE, Benedict AB, Roberts M, Piovia-Scott J, Griffitts JS, Porter SS. Hosts winnow symbionts with multiple layers of absolute and conditional discrimination mechanisms. Proc Biol Sci 2023; 290:20222153. [PMID: 36598018 PMCID: PMC9811631 DOI: 10.1098/rspb.2022.2153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In mutualism, hosts select symbionts via partner choice and preferentially direct more resources to symbionts that provide greater benefits via sanctions. At the initiation of symbiosis, prior to resource exchange, it is not known how the presence of multiple symbiont options (i.e. the symbiont social environment) impacts partner choice outcomes. Furthermore, little research addresses whether hosts primarily discriminate among symbionts via sanctions, partner choice or a combination. We inoculated the legume, Acmispon wrangelianus, with 28 pairs of fluorescently labelled Mesorhizobium strains that vary continuously in quality as nitrogen-fixing symbionts. We find that hosts exert robust partner choice, which enhances their fitness. This partner choice is conditional such that a strain's success in initiating nodules is impacted by other strains in the social environment. This social genetic effect is as important as a strain's own genotype in determining nodulation and has both transitive (consistent) and intransitive (idiosyncratic) effects on the probability that a symbiont will form a nodule. Furthermore, both absolute and conditional partner choice act in concert with sanctions, among and within nodules. Thus, multiple forms of host discrimination act as a series of sieves that optimize host benefits and select for costly symbiont cooperation in mixed symbiont populations.
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Affiliation(s)
- Angeliqua P. Montoya
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
| | - Camille E. Wendlandt
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
| | - Alex B. Benedict
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
| | - Miles Roberts
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
| | - Jonah Piovia-Scott
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
| | - Joel S. Griffitts
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
| | - Stephanie S. Porter
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
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6
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Liu F, Gao L, Wang Q, Fan L, Li J, Du B. Giant babax (Babax waddelli) helpers cheat at provisioning nestlings in poor conditions. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-022-03279-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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7
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Genome-Wide Association Studies across Environmental and Genetic Contexts Reveal Complex Genetic Architecture of Symbiotic Extended Phenotypes. mBio 2022; 13:e0182322. [PMID: 36286519 PMCID: PMC9765617 DOI: 10.1128/mbio.01823-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A goal of modern biology is to develop the genotype-phenotype (G→P) map, a predictive understanding of how genomic information generates trait variation that forms the basis of both natural and managed communities. As microbiome research advances, however, it has become clear that many of these traits are symbiotic extended phenotypes, being governed by genetic variation encoded not only by the host's own genome, but also by the genomes of myriad cryptic symbionts. Building a reliable G→P map therefore requires accounting for the multitude of interacting genes and even genomes involved in symbiosis. Here, we use naturally occurring genetic variation in 191 strains of the model microbial symbiont Sinorhizobium meliloti paired with two genotypes of the host Medicago truncatula in four genome-wide association studies (GWAS) to determine the genomic architecture of a key symbiotic extended phenotype-partner quality, or the fitness benefit conferred to a host by a particular symbiont genotype, within and across environmental contexts and host genotypes. We define three novel categories of loci in rhizobium genomes that must be accounted for if we want to build a reliable G→P map of partner quality; namely, (i) loci whose identities depend on the environment, (ii) those that depend on the host genotype with which rhizobia interact, and (iii) universal loci that are likely important in all or most environments. IMPORTANCE Given the rapid rise of research on how microbiomes can be harnessed to improve host health, understanding the contribution of microbial genetic variation to host phenotypic variation is pressing, and will better enable us to predict the evolution of (and select more precisely for) symbiotic extended phenotypes that impact host health. We uncover extensive context-dependency in both the identity and functions of symbiont loci that control host growth, which makes predicting the genes and pathways important for determining symbiotic outcomes under different conditions more challenging. Despite this context-dependency, we also resolve a core set of universal loci that are likely important in all or most environments, and thus, serve as excellent targets both for genetic engineering and future coevolutionary studies of symbiosis.
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8
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Chouhan B, Tak N, Bissa G, Adhikari D, Barik SK, Sprent JI, James EK, Jha S, Gehlot HS. Evolution of novel strains of Ensifer nodulating the invasive legume Leucaena leucocephala (Lam.) de Wit in different climatic regions of India through lateral gene transfer. FEMS Microbiol Ecol 2022; 98:6643559. [PMID: 35833268 DOI: 10.1093/femsec/fiac086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/24/2022] [Accepted: 07/12/2022] [Indexed: 11/12/2022] Open
Abstract
More than 200 root-nodule bacterial strains were isolated from Leucaena leucocephala growing at 42 sampling sites across 12 states and three union territories of India. Genetic diversity was observed among 114 strains from various climatic zones; based on recA these were identified as strains of Ensifer, Mesorhizobium, Rhizobium and Bradyrhizobium. In MLSA strains clustered into several novel clades and lineages. Ensifer were predominant nodulating genotype isolated from majority of alkaline soils, while Mesorhizobium and Rhizobium strains were isolated from a limited sampling in North-Eastern states with acidic soils. Positive nodulation assays of selected Ensifer representing different genetic combinations of housekeeping and sym genes suggested their broad host range within the closely related mimosoid genera Vachellia, Senegalia, Mimosa and Prosopis. Leucaena selected diverse strains of Ensifer and Mesorhizobium as symbionts depending on available soil pH, climatic and other edaphic conditions in India. Lateral gene transfer seems to play a major role in genetic diversification of Ensifer exhibited in terms of Old World vs. Neotropical genetic make-up and mixed populations at several sites. Although Neotropical Ensifer strains were most symbiotically effective on Leucaena the native Ensifer are promiscuous and particularly well-adapted to a wide range of sampling sites with varied climates and edaphic factors.
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Affiliation(s)
- Bhawana Chouhan
- BNF and Microbial Genomics Lab., Department of Botany, Center of Advanced Study, Jai Narain Vyas University, Jodhpur- 342001, Rajasthan, India
| | - Nisha Tak
- BNF and Microbial Genomics Lab., Department of Botany, Center of Advanced Study, Jai Narain Vyas University, Jodhpur- 342001, Rajasthan, India
| | - Garima Bissa
- BNF and Microbial Genomics Lab., Department of Botany, Center of Advanced Study, Jai Narain Vyas University, Jodhpur- 342001, Rajasthan, India
| | - Dibyendu Adhikari
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow- 226001, Uttar Pradesh, India
| | - Saroj K Barik
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow- 226001, Uttar Pradesh, India
| | - Janet I Sprent
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Euan K James
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Shweta Jha
- Plant Functional Genomics Lab, Biotechnology Unit, Department of Botany, UGC-Centre of Advanced Study, Jai Narain Vyas University, Jodhpur- 342001, Rajasthan, India
| | - Hukam S Gehlot
- BNF and Microbial Genomics Lab., Department of Botany, Center of Advanced Study, Jai Narain Vyas University, Jodhpur- 342001, Rajasthan, India
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9
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Batstone RT, Burghardt LT, Heath KD. Phenotypic and genomic signatures of interspecies cooperation and conflict in naturally occurring isolates of a model plant symbiont. Proc Biol Sci 2022; 289:20220477. [PMID: 35858063 PMCID: PMC9277234 DOI: 10.1098/rspb.2022.0477] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Given the need to predict the outcomes of (co)evolution in host-associated microbiomes, whether microbial and host fitnesses tend to trade-off, generating conflict, remains a pressing question. Examining the relationships between host and microbe fitness proxies at both the phenotypic and genomic levels can illuminate the mechanisms underlying interspecies cooperation and conflict. We examined naturally occurring genetic variation in 191 strains of the model microbial symbiont Sinorhizobium meliloti, paired with each of two host Medicago truncatula genotypes in single- or multi-strain experiments to determine how multiple proxies of microbial and host fitness were related to one another and test key predictions about mutualism evolution at the genomic scale, while also addressing the challenge of measuring microbial fitness. We found little evidence for interspecies fitness conflict; loci tended to have concordant effects on both microbe and host fitnesses, even in environments with multiple co-occurring strains. Our results emphasize the importance of quantifying microbial relative fitness for understanding microbiome evolution and thus harnessing microbiomes to improve host fitness. Additionally, we find that mutualistic coevolution between hosts and microbes acts to maintain, rather than erode, genetic diversity, potentially explaining why variation in mutualism traits persists in nature.
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Affiliation(s)
- Rebecca T. Batstone
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, USA
| | - Liana T. Burghardt
- Department of Plant Science, The Pennsylvania State University, 103 Tyson Building, University Park, PA, 16802 USA
| | - Katy D. Heath
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 286 Morrill Hall, 505 South Goodwin Avenue, Urbana, IL 61801, USA
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10
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Epstein B, Burghardt LT, Heath KD, Grillo MA, Kostanecki A, Hämälä T, Young ND, Tiffin P. Combining GWAS and population genomic analyses to characterize coevolution in a legume-rhizobia symbiosis. Mol Ecol 2022. [PMID: 35793264 DOI: 10.1111/mec.16602] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/03/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022]
Abstract
The mutualism between legumes and rhizobia is clearly the product of past coevolution. However, the nature of ongoing evolution between these partners is less clear. To characterize the nature of recent coevolution between legumes and rhizobia, we used population genomic analysis to characterize selection on functionally annotated symbiosis genes as well as on symbiosis gene candidates identified through a two-species association analysis. For the association analysis, we inoculated each of 202 accessions of the legume host Medicago truncatula with a community of 88 Sinorhizobia (Ensifer) meliloti strains. Multistrain inoculation, which better reflects the ecological reality of rhizobial selection in nature than single-strain inoculation, allows strains to compete for nodulation opportunities and host resources and for hosts to preferentially form nodules and provide resources to some strains. We found extensive host by symbiont, that is, genotype-by-genotype, effects on rhizobial fitness and some annotated rhizobial genes bear signatures of recent positive selection. However, neither genes responsible for this variation nor annotated host symbiosis genes are enriched for signatures of either positive or balancing selection. This result suggests that stabilizing selection dominates selection acting on symbiotic traits and that variation in these traits is under mutation-selection balance. Consistent with the lack of positive selection acting on host genes, we found that among-host variation in growth was similar whether plants were grown with rhizobia or N-fertilizer, suggesting that the symbiosis may not be a major driver of variation in plant growth in multistrain contexts.
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Affiliation(s)
- Brendan Epstein
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Liana T Burghardt
- Department of Plant Sciences, The University of Pennsylvania, University Park, Pennsylvania, USA
| | - Katy D Heath
- Department of Plant Biology, University of Illinois, Urbana, Illinois, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | - Michael A Grillo
- Department of Biology, Loyola University Chicago, Chicago, Illinois, USA
| | - Adam Kostanecki
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Tuomas Hämälä
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA.,School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Nevin D Young
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA.,Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
| | - Peter Tiffin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
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11
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Ezoe H. A general mathematical model for coevolutionary dynamics of mutualisms with partner discrimination. THEOR ECOL-NETH 2022. [DOI: 10.1007/s12080-022-00537-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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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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13
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Moran NP, Caspers BA, Chakarov N, Ernst UR, Fricke C, Kurtz J, Lilie ND, Lo LK, Müller C, R R, Takola E, Trimmer PC, van Benthem KJ, Winternitz J, Wittmann MJ. Shifts between cooperation and antagonism driven by individual variation: a systematic synthesis review. OIKOS 2021. [DOI: 10.1111/oik.08201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Nicholas P. Moran
- Centre for Ocean Life DTU‐Aqua, Technical Univ. of Denmark Lyngby Denmark
- Dept of Evolutionary Biology, Bielefeld Univ. Bielefeld Germany
| | | | | | - Ulrich R. Ernst
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
- Apicultural State Inst., Univ. of Hohenheim Stuttgart Germany
| | - Claudia Fricke
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Joachim Kurtz
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Navina D. Lilie
- Dept of Evolutionary Biology, Bielefeld Univ. Bielefeld Germany
- Dept of Animal Behaviour, Bielefeld Univ. Bielefeld Germany
| | - Lai Ka Lo
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | | | - Reshma R
- Inst. for Evolution and Biodiversity, Univ. of Münster Münster Germany
| | - Elina Takola
- Inst. of Ecology and Evolution, Friedrich Schiller Univ. Jena Jena Germany
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14
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Zeng Y, Wiens JJ. Do mutualistic interactions last longer than antagonistic interactions? Proc Biol Sci 2021; 288:20211457. [PMID: 34493078 PMCID: PMC8424312 DOI: 10.1098/rspb.2021.1457] [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: 06/29/2021] [Accepted: 08/13/2021] [Indexed: 11/12/2022] Open
Abstract
Species interactions are crucial and ubiquitous across organisms. However, it remains unclear how long these interactions last over macroevolutionary timescales, and whether the nature of these interactions (mutualistic versus antagonistic) helps predict how long they persist. Here, we estimated the ages of diverse species interactions, based on phylogenies from 60 studies spanning the Tree of Life. We then tested if mutualistic interactions persist longer than antagonistic interactions. We found that the oldest mutualisms were significantly older than the oldest antagonisms across all organisms, and within plants, fungi, bacteria and protists. Surprisingly, this pattern was reversed in animals, with the oldest mutualisms significantly younger than the oldest antagonisms. We also found that many mutualisms were maintained for hundreds of millions of years (some greater than 1 billion years), providing strong evidence for the long-term stability of mutualisms and for niche conservatism in species interactions.
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Affiliation(s)
- Yichao Zeng
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - John J. Wiens
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
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15
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Pollinator effectiveness is affected by intraindividual behavioral variation. Oecologia 2021; 197:189-200. [PMID: 34392412 DOI: 10.1007/s00442-021-05016-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
Variation in pollinator quality is fundamental to the evolution of plant-pollinator mutualisms and such variation frequently results from differences in foraging behavior. Surprisingly, despite substantial intraindividual variation in pollinator foraging behavior, the consequences for pollen removal and deposition on flowers are largely unknown. We asked how two pollen foraging behaviors of a generalist pollinator (Bombus impatiens) affect removal and deposition of heterospecific and conspecific pollen, key aspects of pollinator quality, for multiple plant species. In addition, we examined how bee body size and pollen placement among body parts shaped pollen movement. We manipulated foraging behavior types using artificial flowers, which donated pollen that captive bees then deposited on three recipient plant species. While body size primarily affected donor pollen removal, foraging behavior primarily affected donor pollen deposition. How behavior affected donor pollen deposition depended on the plant species and the quantity of donor pollen on the bee's abdomen. Plant species with smaller stigmas received significantly less pollen and fewer bees successfully transferred pollen to them. For a single plant species, heterospecific pollen interfered with conspecific pollen deposition, such that more heterospecific pollen on the bee's abdomen resulted in less conspecific pollen deposition on the flower. Thus, intraindividual variation in foraging behavior and its interaction with the amount and placement of acquired pollen and with floral morphology can affect pollinator quality and may shape plant fitness via both conspecific and heterospecific pollen transfer.
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16
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Abstract
Ocean warming is causing repeated mass coral bleaching, leading to catastrophic losses of coral reefs worldwide. Our ability to slow or revert this decline is hampered by an incomplete understanding of the processes underlying the breakdown of the coral–algal symbiosis. Here, we show that heat stress destabilizes the nutrient cycling between corals and their endosymbiotic algae long before bleaching becomes apparent. Notably, increased metabolic energy demands shift the coral–algal symbiosis from a nitrogen- to a carbon-limited state, reducing translocation and recycling of photosynthetic carbon. This effectively undermines the ecological advantage of harboring algal symbionts and directly contributes to the breakdown of the coral–algal symbiosis during heat stress. Recurrent mass bleaching events are pushing coral reefs worldwide to the brink of ecological collapse. While the symptoms and consequences of this breakdown of the coral–algal symbiosis have been extensively characterized, our understanding of the underlying causes remains incomplete. Here, we investigated the nutrient fluxes and the physiological as well as molecular responses of the widespread coral Stylophora pistillata to heat stress prior to the onset of bleaching to identify processes involved in the breakdown of the coral–algal symbiosis. We show that altered nutrient cycling during heat stress is a primary driver of the functional breakdown of the symbiosis. Heat stress increased the metabolic energy demand of the coral host, which was compensated by the catabolic degradation of amino acids. The resulting shift from net uptake to release of ammonium by the coral holobiont subsequently promoted the growth of algal symbionts and retention of photosynthates. Together, these processes form a feedback loop that will gradually lead to the decoupling of carbon translocation from the symbiont to the host. Energy limitation and altered symbiotic nutrient cycling are thus key factors in the early heat stress response, directly contributing to the breakdown of the coral–algal symbiosis. Interpreting the stability of the coral holobiont in light of its metabolic interactions provides a missing link in our understanding of the environmental drivers of bleaching and may ultimately help uncover fundamental processes underpinning the functioning of endosymbioses in general.
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17
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Afkhami ME, Friesen ML, Stinchcombe JR. Multiple Mutualism Effects generate synergistic selection and strengthen fitness alignment in the interaction between legumes, rhizobia and mycorrhizal fungi. Ecol Lett 2021; 24:1824-1834. [PMID: 34110064 DOI: 10.1111/ele.13814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 05/02/2021] [Indexed: 01/05/2023]
Abstract
Nearly all organisms participate in multiple mutualisms, and complementarity within these complex interactions can result in synergistic fitness effects. However, it remains largely untested how multiple mutualisms impact eco-evolutionary dynamics in interacting species. We tested how multiple microbial mutualists-N-fixing bacteria and mycorrrhizal fungi-affected selection and heritability of traits in their shared host plant (Medicago truncatula), as well as fitness alignment between partners. Our results demonstrate for the first time that multiple mutualisms synergistically affect the selection and heritability of host traits and enhance fitness alignment between mutualists. Specifically, we found interaction with multiple microbial symbionts doubled the strength of natural selection on a plant architectural trait, resulted in 2- to 3-fold higher heritability of plant reproductive success, and more than doubled fitness alignment between N-fixing bacteria and plants. These findings show synergism generated by multiple mutualisms extends to key components of microevolutionary change, emphasising the importance of multiple mutualism effects on evolutionary trajectories.
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Affiliation(s)
| | - Maren L Friesen
- Department of Plant Pathology, Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA
| | - John R Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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18
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Six DL, Klepzig KD. Context Dependency in Bark Beetle-Fungus Mutualisms Revisited: Assessing Potential Shifts in Interaction Outcomes Against Varied Genetic, Ecological, and Evolutionary Backgrounds. Front Microbiol 2021; 12:682187. [PMID: 34054789 PMCID: PMC8149605 DOI: 10.3389/fmicb.2021.682187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Context dependency occurs when biological interactions shift in sign or magnitude depending upon genetic, abiotic, and biotic context. Most models of mutualism address systems where interaction outcomes slide along a mutualism-antagonism continuum as environmental conditions vary altering cost-benefit relationships. However, these models do not apply to the many mutualisms that involve by-product benefits and others that do not have antagonistic alternate states. The ubiquity of such mutualisms indicates a need for different approaches and models to understand how environmental variability influences their strength, stability, and ecological roles. In this paper, we apply the concept of context dependency to mutualisms among bark beetles and fungi that span a variety of life strategies and exposures to environmental variability. Bark beetles and their mutualist fungi co-construct a niche based on by-product benefits that allows them to exist in a resource that is otherwise intractable or inaccessible. For the closest of these partnerships, this has resulted in some of the most influential agents of forest mortality in conifer forests worldwide. Understanding these symbioses is key to understanding their influence on forest structure and dynamics and responses to change. We found no evidence that bark beetle mutualisms change in sign as conditions vary, only in magnitude, and that the "closest" (and most environmentally influential) of these partnerships have evolved behaviors and mechanisms to reduce context-dependency and stabilize benefit delivery. The bark beetle-fungus symbioses most likely to slide along a mutualism-antagonism continuum are those involving loosely associated facultative symbionts that may provide benefits under some circumstances and that are horizontally transmitted by the beetle host. Additionally, some symbiotic fungi are never mutualists - these "third party" fungi are exploiters and may shift from commensalism to antagonism depending on environmental context. Our assessment indicates that a careful differentiation between bark beetle-fungus partnerships is crucial to understanding how they influence forests and respond to environmental variability.
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Affiliation(s)
- Diana L Six
- Department of Ecosystem and Conservation Science, The University of Montana, Missoula, MT, United States
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19
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Westhoek A, Clark LJ, Culbert M, Dalchau N, Griffiths M, Jorrin B, Karunakaran R, Ledermann R, Tkacz A, Webb I, James EK, Poole PS, Turnbull LA. Conditional sanctioning in a legume- Rhizobium mutualism. Proc Natl Acad Sci U S A 2021; 118:e2025760118. [PMID: 33941672 PMCID: PMC8126861 DOI: 10.1073/pnas.2025760118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Legumes are high in protein and form a valuable part of human diets due to their interaction with symbiotic nitrogen-fixing bacteria known as rhizobia. Plants house rhizobia in specialized root nodules and provide the rhizobia with carbon in return for nitrogen. However, plants usually house multiple rhizobial strains that vary in their fixation ability, so the plant faces an investment dilemma. Plants are known to sanction strains that do not fix nitrogen, but nonfixers are rare in field settings, while intermediate fixers are common. Here, we modeled how plants should respond to an intermediate fixer that was otherwise isogenic and tested model predictions using pea plants. Intermediate fixers were only tolerated when a better strain was not available. In agreement with model predictions, nodules containing the intermediate-fixing strain were large and healthy when the only alternative was a nonfixer, but nodules of the intermediate-fixing strain were small and white when the plant was coinoculated with a more effective strain. The reduction in nodule size was preceded by a lower carbon supply to the nodule even before differences in nodule size could be observed. Sanctioned nodules had reduced rates of nitrogen fixation, and in later developmental stages, sanctioned nodules contained fewer viable bacteria than nonsanctioned nodules. This indicates that legumes can make conditional decisions, most likely by comparing a local nodule-dependent cue of nitrogen output with a global cue, giving them remarkable control over their symbiotic partners.
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Affiliation(s)
- Annet Westhoek
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
- Systems Biology Doctoral Training Centre, Doctoral Training Centre, University of Oxford, OX1 3NP Oxford, United Kingdom
| | - Laura J Clark
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Michael Culbert
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Neil Dalchau
- Biological Computation, Microsoft Research Cambridge, CB1 2FB Cambridge, United Kingdom
| | - Megan Griffiths
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Beatriz Jorrin
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Ramakrishnan Karunakaran
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, NR4 7UH Norwich, United Kingdom
| | - Raphael Ledermann
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Andrzej Tkacz
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Isabel Webb
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom
| | - Euan K James
- Ecological Sciences, The James Hutton Institute, DD2 5DA Invergowrie, United Kingdom
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom;
| | - Lindsay A Turnbull
- Department of Plant Sciences, University of Oxford, OX1 3RB Oxford, United Kingdom;
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20
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Boyle JA, Simonsen AK, Frederickson ME, Stinchcombe JR. Priority effects alter interaction outcomes in a legume-rhizobium mutualism. Proc Biol Sci 2021; 288:20202753. [PMID: 33715440 PMCID: PMC7944086 DOI: 10.1098/rspb.2020.2753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Priority effects occur when the order of species arrival affects the final community structure. Mutualists often interact with multiple partners in different orders, but if or how priority effects alter interaction outcomes is an open question. In the field, we paired the legume Medicago lupulina with two nodulating strains of Ensifer bacteria that vary in nitrogen-fixing ability. We inoculated plants with strains in different orders and measured interaction outcomes. The first strain to arrive primarily determined plant performance and final relative abundances of rhizobia on roots. Plants that received effective microbes first and ineffective microbes second grew larger than plants inoculated with the same microbes in the opposite order. Our results show that mutualism outcomes can be influenced not just by partner identity, but by the interaction order. Furthermore, hosts receiving high-quality mutualists early can better tolerate low-quality symbionts later, indicating that priority effects may help explain the persistence of ineffective symbionts.
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Affiliation(s)
- Julia A Boyle
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2
| | - Anna K Simonsen
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia.,Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2
| | - John R Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2.,Koffler Scientific Reserve, University of Toronto, Toronto, Ontario, Canada M5S3B2
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21
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Quides KW, Salaheldine F, Jariwala R, Sachs JL. Dysregulation of host-control causes interspecific conflict over host investment into symbiotic organs. Evolution 2021; 75:1189-1200. [PMID: 33521949 DOI: 10.1111/evo.14173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 10/31/2020] [Accepted: 01/08/2021] [Indexed: 12/14/2022]
Abstract
Microbial mutualists provide substantial benefits to hosts that feed back to enhance the fitness of the associated microbes. In many systems, beneficial microbes colonize symbiotic organs, specialized host structures that house symbionts and mediate resources exchanged between parties. Mutualisms are characterized by net benefits exchanged among members of different species, however, inequalities in the magnitude of these exchanges could result in evolutionary conflict, destabilizing the mutualism. We investigated joint fitness effects of root nodule formation, the symbiotic organ of legumes that house nitrogen-fixing rhizobia in planta. We quantified host and symbiont fitness parameters dependent on the number of nodules formed using near-isogenic Lotus japonicus and Mesorhizobium loti mutants, respectively. Empirically estimated fitness functions suggest that legume and rhizobia fitness is aligned as the number of nodules formed increases from zero until the host optimum is reached, a point where aligned fitness interests shift to diverging fitness interests between host and symbiont. However, fitness conflict was only inferred when analyzing wild-type hosts along with their mutants dysregulated for control over nodule formation. These data demonstrate that to avoid conflict, hosts must tightly regulate investment into symbiotic organs maximizing their benefit to cost ratio of associating with microbes.
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Affiliation(s)
- Kenjiro W Quides
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, California, 92521, USA.,Current Institution: Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Fathi Salaheldine
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, California, 92521, USA
| | - Ruchi Jariwala
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, California, 92521, USA
| | - Joel L Sachs
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, California, 92521, USA.,Institute for Integrative Genome Biology, University of California, Riverside, California, USA
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22
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Goldberg Y, Friedman J. Positive interactions within and between populations decrease the likelihood of evolutionary rescue. PLoS Comput Biol 2021; 17:e1008732. [PMID: 33600401 PMCID: PMC7924792 DOI: 10.1371/journal.pcbi.1008732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/02/2021] [Accepted: 01/21/2021] [Indexed: 12/16/2022] Open
Abstract
Positive interactions, including intraspecies cooperation and interspecies mutualisms, play crucial roles in shaping the structure and function of many ecosystems, ranging from plant communities to the human microbiome. While the evolutionary forces that form and maintain positive interactions have been investigated extensively, the influence of positive interactions on the ability of species to adapt to new environments is still poorly understood. Here, we use numerical simulations and theoretical analyses to study how positive interactions impact the likelihood that populations survive after an environment deteriorates, such that survival in the new environment requires quick adaptation via the rise of new mutants-a scenario known as evolutionary rescue. We find that the probability of evolutionary rescue in populations engaged in positive interactions is reduced significantly. In cooperating populations, this reduction is largely due to the fact that survival may require at least a minimal number of individuals, meaning that adapted mutants must arise and spread before the population declines below this threshold. In mutualistic populations, the rescue probability is decreased further due to two additional effects-the need for both mutualistic partners to adapt to the new environment, and competition between the two species. Finally, we show that the presence of cheaters reduces the likelihood of evolutionary rescue even further, making it extremely unlikely. These results indicate that while positive interactions may be beneficial in stable environments, they can hinder adaptation to changing environments and thereby elevate the risk of population collapse. Furthermore, these results may hint at the selective pressures that drove co-dependent unicellular species to form more adaptable organisms able to differentiate into multiple phenotypes, including multicellular life.
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Affiliation(s)
- Yaron Goldberg
- Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Jonathan Friedman
- Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Rehovot, Israel
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23
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O'Brien AM, Jack CN, Friesen ML, Frederickson ME. Whose trait is it anyways? Coevolution of joint phenotypes and genetic architecture in mutualisms. Proc Biol Sci 2021; 288:20202483. [PMID: 33434463 DOI: 10.1098/rspb.2020.2483] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Evolutionary biologists typically envision a trait's genetic basis and fitness effects occurring within a single species. However, traits can be determined by and have fitness consequences for interacting species, thus evolving in multiple genomes. This is especially likely in mutualisms, where species exchange fitness benefits and can associate over long periods of time. Partners may experience evolutionary conflict over the value of a multi-genomic trait, but such conflicts may be ameliorated by mutualism's positive fitness feedbacks. Here, we develop a simulation model of a host-microbe mutualism to explore the evolution of a multi-genomic trait. Coevolutionary outcomes depend on whether hosts and microbes have similar or different optimal trait values, strengths of selection and fitness feedbacks. We show that genome-wide association studies can map joint traits to loci in multiple genomes and describe how fitness conflict and fitness feedback generate different multi-genomic architectures with distinct signals around segregating loci. Partner fitnesses can be positively correlated even when partners are in conflict over the value of a multi-genomic trait, and conflict can generate strong mutualistic dependency. While fitness alignment facilitates rapid adaptation to a new optimum, conflict maintains genetic variation and evolvability, with implications for applied microbiome science.
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Affiliation(s)
- Anna M O'Brien
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Chandra N Jack
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
| | - Maren L Friesen
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA.,Department of Crop and Soil Sciences, Washington State University, Pullman, Washington, USA
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
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24
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Bamba M, Aoki S, Kajita T, Setoguchi H, Watano Y, Sato S, Tsuchimatsu T. Massive rhizobial genomic variation associated with partner quality in Lotus-Mesorhizobium symbiosis. FEMS Microbiol Ecol 2020; 96:5917975. [PMID: 33016310 DOI: 10.1093/femsec/fiaa202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/29/2020] [Indexed: 11/14/2022] Open
Abstract
Variation in partner quality is commonly observed in diverse cooperative relationships, despite the theoretical prediction that selection favoring high-quality partners should eliminate such variation. Here, we investigated how genetic variation in partner quality could be maintained in the nitrogen-fixing mutualism between Lotus japonicus and Mesorhizobium bacteria. We reconstructed de novo assembled full-genome sequences from nine rhizobial symbionts, finding massive variation in the core genome and the similar symbiotic islands, indicating recent horizontal gene transfer (HGT) of the symbiosis islands into diverse Mesorhizobium lineages. A cross-inoculation experiment using 9 sequenced rhizobial symbionts and 15 L. japonicus accessions revealed extensive quality variation represented by plant growth phenotypes, including genotype-by-genotype interactions. Variation in quality was not associated with the presence/absence variation in known symbiosis-related genes in the symbiosis island; rather, it showed significant correlation with the core genome variation. Given the recurrent HGT of the symbiosis islands into diverse Mesorhizobium strains, local Mesorhizobium communities could serve as a major source of variation for core genomes, which might prevent variation in partner quality from fixing, even in the presence of selection favoring high-quality partners. These findings highlight the novel role of HGT of symbiosis islands in maintaining partner quality variation in the legume-rhizobia symbiosis.
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Affiliation(s)
- Masaru Bamba
- Department of Biology (Frontier Science Program), Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.,Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Seishiro Aoki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tadashi Kajita
- Iriomote Station, Tropical Biosphere Research Center, The University of the Ryukyus, 870 Uehara, Taketomi-cho, Yaeyama-gun, Okinawa 907-1541, Japan
| | - Hiroaki Setoguchi
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yasuyuki Watano
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
| | - Shusei Sato
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Takashi Tsuchimatsu
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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25
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Chomicki G, Kiers ET, Renner SS. The Evolution of Mutualistic Dependence. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-110218-024629] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
While the importance of mutualisms across the tree of life is recognized, it is not understood why some organisms evolve high levels of dependence on mutualistic partnerships, while other species remain autonomous or retain or regain minimal dependence on partners. We identify four main pathways leading to the evolution of mutualistic dependence. Then, we evaluate current evidence for three predictions: ( a) Mutualisms with different levels of dependence have distinct stabilizing mechanisms against exploitation and cheating, ( b) less dependent mutualists will return to autonomy more often than those that are highly dependent, and ( c) obligate mutualisms should be less context dependent than facultative ones. Although we find evidence supporting all three predictions, we stress that mutualistic partners follow diverse paths toward—and away from—dependence. We also highlight the need to better examine asymmetry in partner dependence. Recognizing how variation in dependence influences the stability, breakdown, and context dependence of mutualisms generates new hypotheses regarding how and why the benefits of mutualistic partnerships differ over time and space.
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Affiliation(s)
- Guillaume Chomicki
- Department of Bioscience, Durham University, Durham DH1 3LE, United Kingdom
| | - E. Toby Kiers
- Department of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
| | - Susanne S. Renner
- Systematic Botany and Mycology, Department of Biology, University of Munich (LMU), 80638 Munich, Germany
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26
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Symbiotic niche mapping reveals functional specialization by two ectomycorrhizal fungi that expands the host plant niche. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2020.100960] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Younginger BS, Friesen ML. Connecting signals and benefits through partner choice in plant-microbe interactions. FEMS Microbiol Lett 2020; 366:5626345. [PMID: 31730203 DOI: 10.1093/femsle/fnz217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 10/17/2019] [Indexed: 12/20/2022] Open
Abstract
Stabilizing mechanisms in plant-microbe symbioses are critical to maintaining beneficial functions, with two main classes: host sanctions and partner choice. Sanctions are currently presumed to be more effective and widespread, based on the idea that microbes rapidly evolve cheating while retaining signals matching cooperative strains. However, hosts that effectively discriminate among a pool of compatible symbionts would gain a significant fitness advantage. Using the well-characterized legume-rhizobium symbiosis as a model, we evaluate the evidence for partner choice in the context of the growing field of genomics. Empirical studies that rely upon bacteria varying only in nitrogen-fixation ability ignore host-symbiont signaling and frequently conclude that partner choice is not a robust stabilizing mechanism. Here, we argue that partner choice is an overlooked mechanism of mutualism stability and emphasize that plants need not use the microbial services provided a priori to discriminate among suitable partners. Additionally, we present a model that shows that partner choice signaling increases symbiont and host fitness in the absence of sanctions. Finally, we call for a renewed focus on elucidating the signaling mechanisms that are critical to partner choice while further aiming to understand their evolutionary dynamics in nature.
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Affiliation(s)
- Brett S Younginger
- Department of Plant Pathology, Washington State University, PO Box 646430, 345 Johnson Hall, Pullman, WA 99164, USA
| | - Maren L Friesen
- Department of Plant Pathology, Washington State University, PO Box 646430, 345 Johnson Hall, Pullman, WA 99164, USA.,Department of Crop and Soil Sciences, Washington State University, PO Box 646420, 115 Johnson Hall, Pullman, WA 99164, USA
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28
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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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29
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Perez-Lamarque B, Selosse MA, Öpik M, Morlon H, Martos F. Cheating in arbuscular mycorrhizal mutualism: a network and phylogenetic analysis of mycoheterotrophy. THE NEW PHYTOLOGIST 2020; 226:1822-1835. [PMID: 32022272 DOI: 10.1111/nph.16474] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/20/2020] [Indexed: 05/27/2023]
Abstract
Although mutualistic interactions are widespread and essential in ecosystem functioning, the emergence of uncooperative cheaters threatens their stability, unless there are some physiological or ecological mechanisms limiting interactions with cheaters. In this framework, we investigated the patterns of specialization and phylogenetic distribution of mycoheterotrophic cheaters vs noncheating autotrophic plants and their respective fungi, in a global arbuscular mycorrhizal network with> 25 000 interactions. We show that mycoheterotrophy evolved repeatedly among vascular plants, suggesting low phylogenetic constraints for plants. However, mycoheterotrophic plants are significantly more specialized than autotrophic plants, and they tend to be associated with specialized and closely related fungi. These results raise new hypotheses about the mechanisms (e.g. sanctions, or habitat filtering) that actually limit the interaction of mycoheterotrophic plants and their associated fungi with the rest of the autotrophic plants. Beyond mycorrhizal symbiosis, this unprecedented comparison of mycoheterotrophic vs autotrophic plants provides a network and phylogenetic framework to assess the presence of constraints upon cheating emergences in mutualisms.
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Affiliation(s)
- Benoît Perez-Lamarque
- Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d'histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP39, 57 rue Cuvier, 75 005, Paris, France
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, 75 005, Paris, France
| | - Marc-André Selosse
- Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d'histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP39, 57 rue Cuvier, 75 005, Paris, France
- Department of Plant Taxonomy and Nature Conservation, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland
| | - Maarja Öpik
- University of Tartu, 40 Lai Street, 51 005, Tartu, Estonia
| | - Hélène Morlon
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, 75 005, Paris, France
| | - Florent Martos
- Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d'histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP39, 57 rue Cuvier, 75 005, Paris, France
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30
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Abstract
Abstract
Fig tree–fig wasp mutualisms are diverse and underpin much biodiversity. The wasps (Agaonidae) are the sole pollinators of the trees (Ficus). Figs are enclosed inflorescences, each of which contains many small flowers. Female wasps (foundresses) enter receptive figs to spread pollen and to lay their eggs individually into fig flowers. As they oviposit, wasps also inject chemicals that transform individual flower ovaries into galls that will feed and house wasp offspring. For fig tree–fig wasp mutualisms to persist, the trees must set seed; therefore, the wasps have both to pollinate and to fail to gall all flower ovaries. However, wasps that avoid pollination costs and/or gall all flowers are predicted to outcompete more cooperative conspecifics, resulting in destabilisation of the mutualism. Here, I review the literature on why wasps pollinate by focusing on how trees reduce investment to unpollinated figs, resulting in ‘sanctions’ to wasps that fail to pollinate via reduced production of offspring. I also review the mechanisms that prevent wasps from galling all flowers, mainly those in monoecious Ficus, that also result in wasps predominantly galling longer flowers whilst leaving shorter flowers to become seeds. I make suggestions for future work and conclude by reaffirming why multiple processes promote stability in fig tree–fig wasp mutualisms.
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Affiliation(s)
- Derek W Dunn
- College of Life Sciences, Northwest University, Xian, China
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31
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Affiliation(s)
- Takefumi Nakazawa
- Dept of Life Sciences, National Cheng Kung Univ. No.1, University Road Tainan City 701 Taiwan
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32
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Batstone RT, Peters MAE, Simonsen AK, Stinchcombe JR, Frederickson ME. Environmental variation impacts trait expression and selection in the legume-rhizobium symbiosis. AMERICAN JOURNAL OF BOTANY 2020; 107:195-208. [PMID: 32064599 DOI: 10.1002/ajb2.1432] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 11/04/2019] [Indexed: 05/22/2023]
Abstract
PREMISE The ecological outcomes of mutualism are well known to shift across abiotic or biotic environments, but few studies have addressed how different environments impact evolutionary responses, including the intensity of selection on and the expression of genetic variance in key mutualism-related traits. METHODS We planted 30 maternal lines of the legume Medicago lupulina in four field common gardens and compared our measures of selection on and genetic variance in nodulation, a key trait reflecting legume investment in the symbiosis, with those from a previous greenhouse experiment using the same 30 M. lupulina lines. RESULTS We found that both the mean and genetic variance for nodulation were much greater in the greenhouse than in the field and that the form of selection on nodulation significantly differed across environments. We also found significant genotype-by-environment (G × E) effects for fitness-related traits that were generated by differences in the rank order of plant lines among environments. CONCLUSIONS Overall, our results suggest that the expression of genotypic variation and selection on nodulation differ across environments. In the field, significant rank-order changes for plant fitness potentially help maintain genetic variation in natural populations, even in the face of directional or stabilizing selection.
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Affiliation(s)
- Rebecca T Batstone
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Carl Woese Institute for Genomic Biology, University of Illinois at Champaign-Urbana, Urbana, IL, 61801, USA
| | - Madeline A E Peters
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Anna K Simonsen
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - John R Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Koffler Scientific Reserve, University of Toronto, King, ON, L7B 1K5, Canada
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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33
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Gano-Cohen KA, Wendlandt CE, Al Moussawi K, Stokes PJ, Quides KW, Weisberg AJ, Chang JH, Sachs JL. Recurrent mutualism breakdown events in a legume rhizobia metapopulation. Proc Biol Sci 2020; 287:20192549. [PMID: 31992172 DOI: 10.1098/rspb.2019.2549] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Bacterial mutualists generate major fitness benefits for eukaryotes, reshaping the host phenotype and its interactions with the environment. Yet, microbial mutualist populations are predicted to generate mutants that defect from providing costly services to hosts while maintaining the capacity to exploit host resources. Here, we examined the mutualist service of symbiotic nitrogen fixation in a metapopulation of root-nodulating Bradyrhizobium spp. that associate with the native legume Acmispon strigosus. We quantified mutualism traits of 85 Bradyrhizobium isolates gathered from a 700 km transect in California spanning 10 sampled A. strigosus populations. We clonally inoculated each Bradyrhizobium isolate onto A. strigosus hosts and quantified nodulation capacity and net effects of infection, including host growth and isotopic nitrogen concentration. Six Bradyrhizobium isolates from five populations were categorized as ineffective because they formed nodules but did not enhance host growth via nitrogen fixation. Six additional isolates from three populations failed to form root nodules. Phylogenetic reconstruction inferred two types of mutualism breakdown, including three to four independent losses of effectiveness and five losses of nodulation capacity on A. strigosus. The evolutionary and genomic drivers of these mutualism breakdown events remain poorly understood.
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Affiliation(s)
- Kelsey A Gano-Cohen
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
| | - Camille E Wendlandt
- Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Khadija Al Moussawi
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, CA, USA
| | - Peter J Stokes
- Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Kenjiro W Quides
- Department of Evolution Ecology and Organismal Biology, University of California, Riverside, CA, USA
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Joel L Sachs
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA.,Department of Botany and Plant Sciences, University of California, Riverside, CA, USA.,Department of Evolution Ecology and Organismal Biology, University of California, Riverside, CA, USA.,Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
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34
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Kaur KM, Malé PJG, Spence E, Gomez C, Frederickson ME. Using text-mined trait data to test for cooperate-and-radiate co-evolution between ants and plants. PLoS Comput Biol 2019; 15:e1007323. [PMID: 31581264 PMCID: PMC6776258 DOI: 10.1371/journal.pcbi.1007323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 08/05/2019] [Indexed: 01/14/2023] Open
Abstract
Mutualisms may be “key innovations” that spur lineage diversification by augmenting niche breadth, geographic range, or population size, thereby increasing speciation rates or decreasing extinction rates. Whether mutualism accelerates diversification in both interacting lineages is an open question. Research suggests that plants that attract ant mutualists have higher diversification rates than non-ant associated lineages. We ask whether the reciprocal is true: does the interaction between ants and plants also accelerate diversification in ants, i.e. do ants and plants cooperate-and-radiate? We used a novel text-mining approach to determine which ant species associate with plants in defensive or seed dispersal mutualisms. We investigated patterns of lineage diversification across a recent ant phylogeny using BiSSE, BAMM, and HiSSE models. Ants that associate mutualistically with plants had elevated diversification rates compared to non-mutualistic ants in the BiSSE model, with a similar trend in BAMM, suggesting ants and plants cooperate-and-radiate. However, the best-fitting model was a HiSSE model with a hidden state, meaning that diversification models that do not account for unmeasured traits are inappropriate to assess the relationship between mutualism and ant diversification. Against a backdrop of diversification rate heterogeneity, the best-fitting HiSSE model found that mutualism actually decreases diversification: mutualism evolved much more frequently in rapidly diversifying ant lineages, but then subsequently slowed diversification. Thus, it appears that ant lineages first radiated, then cooperated with plants. Many plants and animals depend on other species for nutrition, protection, or dispersal, a type of ecological interaction known as mutualism. Mutualisms often help organisms thrive in new or harsh environments, thereby increasing their ecological success. We studied whether mutualism also increases evolutionary success by affecting lineage diversification, or the net result of the formation and loss of species over evolutionary time (i.e., speciation minus extinction). We focused on the widespread mutualism between ants and plants, in which ants act as protective ‘bodyguards’ or seed dispersers for plants and gain food or shelter in return. Previous research has found that the evolution of ant-plant mutualisms increased plant diversification. Here, we asked whether the same is true for ant diversification. We used a novel, automated approach to gather trait data from the abstracts of over 89,000 scientific articles about ants, and identified 432 mutualistic ant species and 2,909 non-mutualistic ant species. We then used this trait information to model how mutualism has evolved and influenced diversification across a recent ant phylogeny. Our analysis suggests that instead of causally enhancing diversification, mutualism evolves more often in lineages that are already diversifying quickly and then slows ant diversification.
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Affiliation(s)
- Katrina M. Kaur
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
| | - Pierre-Jean G. Malé
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Erik Spence
- SciNet Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Crisanto Gomez
- Departament Ciències Ambientals, Universitat de Girona, Girona, Spain
| | - Megan E. Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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35
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Archetti M. Maintenance of variation in mutualism by screening. Evolution 2019; 73:2036-2043. [DOI: 10.1111/evo.13816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 06/24/2019] [Accepted: 07/02/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Marco Archetti
- Department of BiologyPennsylvania State University University Park Pennsylvania 18602
- Huck Institutes of the Life SciencesPennsylvania State University University Park Pennsylvania 18602
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36
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Clark TJ, Friel CA, Grman E, Friesen ML, Shachar-Hill Y. Unfair trade underground revealed by integrating data with Nash bargaining models. THE NEW PHYTOLOGIST 2019; 222:1325-1337. [PMID: 30671951 DOI: 10.1111/nph.15703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Mutually beneficial resource exchange is fundamental to global biogeochemical cycles and plant and animal nutrition. However, there is inherent potential conflict in mutualisms, as each organism benefits more when the exchange ratio ('price') minimizes its own costs and maximizes its benefits. Understanding the bargaining power that each partner has in these interactions is key to our ability to predict the exchange ratio and therefore the functionality of the cell, organism, community and ecosystem. We tested whether partners have symmetrical ('fair') or asymmetrical ('unfair') bargaining power in a legume-rhizobia nitrogen-fixing symbiosis using measurements of carbon and nitrogen dynamics in a mathematical modeling framework derived from economic theory. A model of symmetric bargaining power was not consistent with our data. Instead, our data indicate that the growth benefit to the plant (Medicago truncatula) has greater weight in determining trade dynamics than the benefit to the bacteria. Quantitative estimates of the relative power of the plant revealed that the plant's influence rises as soil nitrogen availability decreases and trade benefits to both partners increase. Our finding that M. truncatula legumes have more bargaining power than their rhizobial partner at lower nitrogen availabilities highlights the importance of context-dependence for the evolution of mutualism with increasing nutrient deposition.
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Affiliation(s)
- Teresa J Clark
- Department of Plant Biology, Michigan State University, 612 Wilson Rd., East Lansing, MI, 48824, USA
| | - Colleen A Friel
- Department of Plant Biology, Michigan State University, 612 Wilson Rd., East Lansing, MI, 48824, USA
| | - Emily Grman
- Department of Biology, Eastern Michigan University, 441 Mark Jefferson Science Complex, Ypsilanti, MI, 48197, USA
| | - Maren L Friesen
- Department of Plant Biology, Michigan State University, 612 Wilson Rd., East Lansing, MI, 48824, USA
- Department of Plant Pathology, Washington State University, Johnson Hall Rm 345, Pullman, WA, 99164, USA
- Department of Crop and Soil Sciences, Washington State University, Johnson Hall Rm 115, Pullman, WA, 99164, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, 612 Wilson Rd., East Lansing, MI, 48824, USA
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37
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Dunkley K, Ioannou CC, Whittey KE, Cable J, Perkins SE. Cleaner personality and client identity have joint consequences on cleaning interaction dynamics. Behav Ecol 2019; 30:703-712. [PMID: 31210720 PMCID: PMC6562305 DOI: 10.1093/beheco/arz007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/24/2018] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Abstract
Mutualistic interactions involve 2 species beneficially cooperating, but it is not clear how these interactions are maintained. In many mutualisms, one species interacts with multiple species, and since partners differ in terms of the commodities they trade, partner identity will directly influence the decisions and behaviors of interacting individuals. Here, we investigated the consequences of within and between-species diversity on a model cleaner-client interaction in a natural environment, by quantifying the behavior of both partners. We found that the predominant Caribbean cleaner fish, the sharknose goby (Elacatinus evelynae), shows personality variation as we documented repeatable individual differences in activity, boldness, and exploratory behaviors. Personality variation was associated with cleaner-client interactions: cleaner boldness and activity were significantly related to posing by clients and cleaning, respectively. Cleaner personality variation was also associated with the functional identity (sociality, mobility, body size, and trophic level) of clients posing and being cleaned. We thus demonstrate that partner identity can have consequences on mutualistic outcomes which will contribute to the context-dependency and highly heterogeneous patterns we observe at a population level. We also suggest that within- and between-species differences have consequences on partner choice, a feature that has been previously thought to be absent from these cleaner-client interactions.
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Affiliation(s)
- Katie Dunkley
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, UK
| | | | - Kathryn E Whittey
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, UK
| | - Jo Cable
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, UK
| | - Sarah E Perkins
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, UK
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38
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Gano‐Cohen KA, Wendlandt CE, Stokes PJ, Blanton MA, Quides KW, Zomorrodian A, Adinata ES, Sachs JL. Interspecific conflict and the evolution of ineffective rhizobia. Ecol Lett 2019; 22:914-924. [DOI: 10.1111/ele.13247] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/07/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Kelsey A. Gano‐Cohen
- Department of Microbiology and Plant Pathology University of California Riverside CA USA
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Camille E. Wendlandt
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
- Department of Botany and Plant Sciences University of California Riverside CA USA
| | - Peter J. Stokes
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Mia A. Blanton
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Kenjiro W. Quides
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Avissa Zomorrodian
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Eunice S. Adinata
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
| | - Joel L. Sachs
- Department of Microbiology and Plant Pathology University of California Riverside CA USA
- Department of Evolution Ecology & Organismal Biology University of California Riverside CA USA
- Department of Botany and Plant Sciences University of California Riverside CA USA
- Institute for Integrative Genome Biology University of California Riverside CA USA
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39
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Sun BF, Wang RW. Foundress numbers and the timing of selective events during interactions between figs and fig wasps. Sci Rep 2019; 9:3420. [PMID: 30833578 PMCID: PMC6399315 DOI: 10.1038/s41598-018-37498-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 12/07/2018] [Indexed: 11/09/2022] Open
Abstract
In intimate mutualisms between hosts and symbionts, selection can act repeatedly over the development times of the interacting individuals. Although much is now known about the overall ecological conditions that favor the evolution of mutualism, a current challenge is to understand how natural selection acts on the number and kinds of partners to shape the evolution and stability of these interactions. Using the obligate fig-fig wasp mutualism, our experiments showed that the proportion of figs developed to maturity increased quickly to 1.0 as the number of foundresses increased, regardless of whether the foundresses carried pollen. Selection against pollen-free wasps did not occur at this early stage in fig development. Within figs that developed, the proportion of galls producing adult wasps remained high as the number of pollen-carrying foundresses increases. In contrast, the proportion of galls producing adult wasps decreased as the number of pollen-free foundresses increased. Viable seed production increased as the number or proportion of pollen-carrying foundresses increased, but the average number of wasp offspring per pollen-carrying foundress was highest when she was the sole foundress. These results show that figs and their pollinator wasps differ in how fitness effects are distributed throughout the development of the interaction and depend on the number and proportion of pollen-carrying foundresses contributing to the interaction. These results suggest that temporal fluctuations in the local number and proportion of pollen-carrying wasps available to enter figs are likely to have strong but different effects on the figs and the wasps.
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Affiliation(s)
- Bao-Fa Sun
- Center for Ecological and Environmental Sciences, Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, China. .,CAS Key Laboratory of Genomics and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Rui-Wu Wang
- Center for Ecological and Environmental Sciences, Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, China.
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40
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Bogar L, Peay K, Kornfeld A, Huggins J, Hortal S, Anderson I, Kennedy P. Plant-mediated partner discrimination in ectomycorrhizal mutualisms. MYCORRHIZA 2019; 29:97-111. [PMID: 30617861 DOI: 10.1007/s00572-018-00879-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/26/2018] [Indexed: 05/22/2023]
Abstract
Although ectomycorrhizal fungi have well-recognized effects on ecological processes ranging from plant community dynamics to carbon cycling rates, it is unclear if plants are able to actively influence the structure of these fungal communities. To address this knowledge gap, we performed two complementary experiments to determine (1) whether ectomycorrhizal plants can discriminate among potential fungal partners, and (2) to what extent the plants might reward better mutualists. In experiment 1, split-root Larix occidentalis seedlings were inoculated with spores from three Suillus species (S. clintonianus, S. grisellus, and S. spectabilis). In experiment 2, we manipulated the symbiotic quality of Suillus brevipes isolates on split-root Pinus muricata seedlings by changing the nitrogen resources available, and used carbon-13 labeling to track host investment in fungi. In experiment 1, we found that hosts can discriminate in multi-species settings. The split-root seedlings inhibited colonization by S. spectabilis whenever another fungus was available, despite similar benefits from all three fungi. In experiment 2, we found that roots and fungi with greater nitrogen supplies received more plant carbon. Our results suggest that plants may be able to regulate this symbiosis at a relatively fine scale, and that this regulation can be integrated across spatially separated portions of a root system.
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Affiliation(s)
- Laura Bogar
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305, USA.
| | - Kabir Peay
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305, USA
| | - Ari Kornfeld
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Julia Huggins
- Department of Plant & Microbial Biology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Sara Hortal
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Ian Anderson
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Peter Kennedy
- Department of Plant & Microbial Biology, University of Minnesota, Saint Paul, MN, 55108, USA
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41
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Zhang X, Dunn DW, Wen X, Sun B, Wang R. Differential deployment of sanctioning mechanisms by male and female host trees in a gynodioecious fig–wasp mutualism. Ecology 2019; 100:e02597. [DOI: 10.1002/ecy.2597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 11/09/2018] [Accepted: 12/03/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Xiao‐Wei Zhang
- Centre for Ecological and Environmental Sciences Northwest Polytechnical University Xi'an 710072 China
| | - Derek W. Dunn
- College of Life Sciences Northwest University Xi'an Shaanxi 710069 China
| | - Xiao‐Lan Wen
- Kunming Institute of Zoology Chinese Academy of Sciences Kunming Yunnan 650223 China
| | - Bao‐Fa Sun
- CAS Key Laboratory of Genetics and Precision Medicine Beijing Institute of Genomics Chinese Academy of Sciences Beijing 100101 China
| | - Rui‐Wu Wang
- Centre for Ecological and Environmental Sciences Northwest Polytechnical University Xi'an 710072 China
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42
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O’Brien AM, Sawers RJH, Ross-Ibarra J, Strauss SY. Evolutionary Responses to Conditionality in Species Interactions across Environmental Gradients. Am Nat 2018; 192:715-730. [DOI: 10.1086/700118] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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43
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Porter SS, Faber-Hammond J, Montoya AP, Friesen ML, Sackos C. Dynamic genomic architecture of mutualistic cooperation in a wild population of Mesorhizobium. ISME JOURNAL 2018; 13:301-315. [PMID: 30218020 PMCID: PMC6331556 DOI: 10.1038/s41396-018-0266-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/01/2018] [Accepted: 08/04/2018] [Indexed: 12/14/2022]
Abstract
Research on mutualism seeks to explain how cooperation can be maintained when uncooperative mutants co-occur with cooperative kin. Gains and losses of the gene modules required for cooperation punctuate symbiont phylogenies and drive lifestyle transitions between cooperative symbionts and uncooperative free-living lineages over evolutionary time. Yet whether uncooperative symbionts commonly evolve from within cooperative symbiont populations or from within distantly related lineages with antagonistic or free-living lifestyles (i.e., third-party mutualism exploiters or parasites), remains controversial. We use genomic data to show that genotypes that differ in the presence or absence of large islands of symbiosis genes are common within a single wild recombining population of Mesorhizobium symbionts isolated from host tissues and are an important source of standing heritable variation in cooperation in this population. In a focal population of Mesorhizobium, uncooperative variants that lack a symbiosis island segregate at 16% frequency in nodules, and genome size and symbiosis gene number are positively correlated with cooperation. This finding contrasts with the genomic architecture of variation in cooperation in other symbiont populations isolated from host tissues in which the islands of genes underlying cooperation are ubiquitous and variation in cooperation is primarily driven by allelic substitution and individual gene gain and loss events. Our study demonstrates that uncooperative mutants within mutualist populations can comprise a significant component of genetic variation in nature, providing biological rationale for models and experiments that seek to explain the maintenance of mutualism in the face of non-cooperators.
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Affiliation(s)
- Stephanie S Porter
- School of Biological Sciences, Washington State University, Vancouver, WA, 98686, USA.
| | - Joshua Faber-Hammond
- School of Biological Sciences, Washington State University, Vancouver, WA, 98686, USA
| | - Angeliqua P Montoya
- School of Biological Sciences, Washington State University, Vancouver, WA, 98686, USA
| | - Maren L Friesen
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA.,Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Cynthia Sackos
- School of Biological Sciences, Washington State University, Vancouver, WA, 98686, USA
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Jandér KC, Dafoe A, Herre EA. Fitness reduction for uncooperative fig wasps through reduced offspring size: a third component of host sanctions. Ecology 2018; 97:2491-2500. [PMID: 27859079 DOI: 10.1002/ecy.1471] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/20/2016] [Accepted: 04/25/2016] [Indexed: 11/10/2022]
Abstract
Mutually beneficial interactions between two species-mutualisms-are ancient, diverse, and of fundamental ecological importance. Nonetheless, factors that prevent one partner from reaping the benefits of the interaction without paying the cost are still poorly understood. Fig trees and their unique pollinators, fig wasps, present a powerful model system for studying mutualism stability. Both partners depend completely on each other for reproduction, cooperation levels can be manipulated, and the resulting field-based fitness quantified. Previous work has shown that fig trees can impose two types of host sanctions that reduce the fitness of wasps that do not pollinate: (1) fig abortion, which kills all developing larvae, and (2) reduced number of wasp offspring in figs that are not aborted. Here we demonstrate a third component of host sanctions. Through manipulative field experiments, we show that for four of five studied species, offspring of pollen-free foundresses are only 50-90% the size of offspring of pollinating foundresses. We further show that in all four studied species, smaller wasps are less likely to reach and enter a flowering fig to become foundresses themselves. Therefore, the experimentally determined size reduction of offspring is estimated to cause an additional reduction of up to 80% in fitness for a pollen-free foundress. We determine that the size reduction of pollen-free offspring acts on the level of the entire fig fruit rather than on individual flowers. These results show that estimates of the fitness effect of host sanctions on uncooperative symbionts should consider not only offspring quantity but also offspring quality. We discuss implications beyond the fig tree-fig wasp mutualism.
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Affiliation(s)
- K C Jandér
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138, USA.,Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06520, USA.,Smithsonian Tropical Research Institute, Unit 9100, Box 0948, DPO AA 34002-9998, Miami, Florida, 34002-9998, USA
| | - A Dafoe
- Department of Political Science, Yale University, New Haven, Connecticut, 06520, USA
| | - E A Herre
- Smithsonian Tropical Research Institute, Unit 9100, Box 0948, DPO AA 34002-9998, Miami, Florida, 34002-9998, USA
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Abstract
Symbiosis is a process that can generate evolutionary novelties and can extend the phenotypic niche space of organisms. Symbionts can act together with their hosts to co-construct host organs, within which symbionts are housed. Once established within hosts, symbionts can also influence various aspects of host phenotype, such as resource acquisition, protection from predation by acquisition of toxicity, as well as behaviour. Once symbiosis is established, its fidelity between generations must be ensured. Hosts evolve various mechanisms to screen unwanted symbionts and to facilitate faithful transmission of mutualistic partners between generations. Microbes are the most important symbionts that have influenced plant and animal phenotypes; multicellular organisms engage in developmental symbioses with microbes at many stages in ontogeny. The co-construction of niches may result in composite organisms that are physically nested within each other. While it has been advocated that these composite organisms need new evolutionary theories and perspectives to describe their properties and evolutionary trajectories, it appears that standard evolutionary theories are adequate to explore selection pressures on their composite or individual traits. Recent advances in our understanding of composite organisms open up many important questions regarding the stability and transmission of these units.
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Affiliation(s)
- Renee M Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru 560 012, India.
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46
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Batstone RT, Carscadden KA, Afkhami ME, Frederickson ME. Using niche breadth theory to explain generalization in mutualisms. Ecology 2018; 99:1039-1050. [PMID: 29453827 DOI: 10.1002/ecy.2188] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/12/2017] [Accepted: 01/22/2018] [Indexed: 02/02/2023]
Abstract
For a mutualism to remain evolutionarily stable, theory predicts that mutualists should limit their associations to high-quality partners. However, most mutualists either simultaneously or sequentially associate with multiple partners that confer the same type of reward. By viewing mutualisms through the lens of niche breadth evolution, we outline how the environment shapes partner availability and relative quality, and ultimately a focal mutualist's partner breadth. We argue that mutualists that associate with multiple partners may have a selective advantage compared to specialists for many reasons, including sampling, complementarity, and portfolio effects, as well as the possibility that broad partner breadth increases breadth along other niche axes. Furthermore, selection for narrow partner breadth is unlikely to be strong when the environment erodes variation in partner quality, reduces the costs of interacting with low-quality partners, spatially structures partner communities, or decreases the strength of mutualism. Thus, we should not be surprised that most mutualists have broad partner breadth, even if it allows for ineffective partners to persist.
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Affiliation(s)
- Rebecca T Batstone
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - Kelly A Carscadden
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, 80309, USA
| | - Michelle E Afkhami
- Department of Biology, University of Miami, Coral Gables, Florida, 33146, USA
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
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47
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Ossler JN, Heath KD. Shared Genes but Not Shared Genetic Variation: Legume Colonization by Two Belowground Symbionts. Am Nat 2018. [DOI: 10.1086/695829] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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48
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Arcila Hernández LM, Sanders JG, Miller GA, Ravenscraft A, Frederickson ME. Ant-plant mutualism: a dietary by-product of a tropical ant's macronutrient requirements. Ecology 2017; 98:3141-3151. [DOI: 10.1002/ecy.2036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/08/2017] [Accepted: 09/14/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Lina M. Arcila Hernández
- Department of Ecology & Evolutionary Biology; University of Toronto; 25 Willcocks Street Toronto Ontario M5S 3B2 Canada
| | - Jon G. Sanders
- Department of Organismic & Evolutionary Biology; Harvard University; 26 Oxford Street Cambridge Massachusetts 02138 USA
| | - Gabriel A. Miller
- Department of Organismic & Evolutionary Biology; Harvard University; 26 Oxford Street Cambridge Massachusetts 02138 USA
| | - Alison Ravenscraft
- Department of Organismic & Evolutionary Biology; Harvard University; 26 Oxford Street Cambridge Massachusetts 02138 USA
| | - Megan E. Frederickson
- Department of Ecology & Evolutionary Biology; University of Toronto; 25 Willcocks Street Toronto Ontario M5S 3B2 Canada
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49
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Hillesland KL. Evolution on the bright side of life: microorganisms and the evolution of mutualism. Ann N Y Acad Sci 2017; 1422:88-103. [PMID: 29194650 DOI: 10.1111/nyas.13515] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 01/15/2023]
Abstract
Mutualistic interactions, where two interacting species have a net beneficial effect on each other's fitness, play a crucial role in the survival and evolution of many species. Despite substantial empirical and theoretical work in past decades, the impact of these interactions on natural selection is not fully understood. In addition, mutualisms between microorganisms have been largely ignored, even though they are ecologically important and can be used as tools to bridge the gap between theory and empirical work. Here, I describe two problems with our current understanding of natural selection in mutualism and highlight the properties of microbial mutualisms that could help solve them. One problem is that bias and methodological problems have limited our understanding of the variety of mechanisms by which species may adapt to mutualism. Another problem is that it is rare for experiments testing coevolution in mutualism to address whether each species has adapted to evolutionary changes in its partner. These problems can be addressed with genome resequencing and time-shift experiments, techniques that are easier to perform in microorganisms. In addition, microbial mutualisms may inspire novel insights and hypotheses about natural selection in mutualism.
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50
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Life and death in facultative chemosymbioses: control of bacterial population dynamics in the Thyasiridae. Symbiosis 2017. [DOI: 10.1007/s13199-017-0525-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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