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Laurich JR, Reid CG, Biel C, Wu T, Knox C, Frederickson ME. Genetic architecture of multiple mutualisms and mating system in Turnera ulmifolia. J Evol Biol 2023; 36:280-295. [PMID: 36196911 DOI: 10.1111/jeb.14098] [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: 12/19/2021] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 01/11/2023]
Abstract
Plants often associate with multiple arthropod mutualists. These partners provide important services to their hosts, but multiple interactions can constrain a plant's ability to respond to complex, multivariate selection. Here, we quantified patterns of genetic variance and covariance among rewards for pollination, biotic defence and seed dispersal mutualisms in multiple populations of Turnera ulmifolia to better understand how the genetic architecture of multiple mutualisms might influence their evolution. We phenotyped plants cultivated from 17 Jamaican populations for several mutualism and mating system-related traits. We then fit genetic variance-covariance (G) matrices for the island metapopulation and the five largest individual populations. At the metapopulation level, we observed significant positive genetic correlations among stigma-anther separation, floral nectar production and extrafloral nectar production. These correlations have the potential to significantly constrain or facilitate the evolution of multiple mutualisms in T. ulmifolia and suggest that pollination, seed dispersal and defence mutualisms do not evolve independently. In particular, we found that positive genetic correlations between floral and extrafloral nectar production may help explain their stable coexistence in the face of physiological trade-offs and negative interactions between pollinators and ant bodyguards. Locally, we found only small differences in G among our T. ulmifolia populations, suggesting that geographic variation in G may not shape the evolution of multiple mutualisms.
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Affiliation(s)
- Jason R Laurich
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher G Reid
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Caroline Biel
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Tianbi Wu
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Faculty of the Environment, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christopher Knox
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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2
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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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3
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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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Vaidya P, Stinchcombe JR. The Potential for Genotype-by-Environment Interactions to Maintain Genetic Variation in a Model Legume-Rhizobia Mutualism. PLANT COMMUNICATIONS 2020; 1:100114. [PMID: 33367267 PMCID: PMC7747969 DOI: 10.1016/j.xplc.2020.100114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/10/2020] [Accepted: 10/08/2020] [Indexed: 05/10/2023]
Abstract
The maintenance of genetic variation in mutualism-related traits is key for understanding mutualism evolution, yet the mechanisms maintaining variation remain unclear. We asked whether genotype-by-environment (G×E) interaction is a potential mechanism maintaining variation in the model legume-rhizobia system, Medicago truncatula-Ensifer meliloti. We planted 50 legume genotypes in a greenhouse under ambient light and shade to reflect reduced carbon availability for plants. We found an expected reduction under shaded conditions for plant performance traits, such as leaf number, aboveground and belowground biomass, and a mutualism-related trait, nodule number. We also found G×E for nodule number, with ∼83% of this interaction due to shifts in genotype fitness rank order across light environments, coupled with strong positive directional selection on nodule number regardless of light environment. Our results suggest that G×E can maintain genetic variation in a mutualism-related trait that is under consistent positive directional selection across light environments.
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Affiliation(s)
- Priya Vaidya
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada
- Corresponding author
| | - John R. Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada
- Koffler Scientific Reserve at Joker's Hill, University of Toronto, Toronto, ON M5S3B2, Canada
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Franklin JB, Hockey K, Maherali H. Population-level variation in host plant response to multiple microbial mutualists. AMERICAN JOURNAL OF BOTANY 2020; 107:1389-1400. [PMID: 33029783 DOI: 10.1002/ajb2.1543] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Multipartite mutualisms are widespread in nature, but population-level variation in these interactions is rarely quantified. In the model multipartite mutualism between legumes, arbuscular mycorrhizal (AM) fungi and rhizobia bacteria, host responses to microbial partners are expected to be synergistic because the nutrients provided by each microbe colimit plant growth, but tests of this prediction have not been done in multiple host populations. METHODS To test whether plant response to associations with AM fungi and rhizobia varies among host populations and whether synergistic responses to microbial mutualists are common, we grew 34 Medicago truncatula populations in a factorial experiment that manipulated the presence or absence of each mutualist. RESULTS Plant growth increased in response to each mutualist, but there were no synergistic effects. Instead, plant response to inoculation with AM fungi was an order of magnitude higher than with rhizobia. Plant response to AM fungi varied among populations, whereas responses to rhizobia were relatively uniform. There was a positive correlation between plant host response to each mutualist but no correlation between AM fungal colonization and rhizobia nodulation of plant roots. CONCLUSIONS The greater population divergence in host response to AM fungi relative to rhizobia, weak correlation in host response to each microbial mutualist, and the absence of a correlation between measures of AM fungal and rhizobia performance suggests that each plant-microbe mutualism evolved independently among M. truncatula populations.
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Affiliation(s)
- James B Franklin
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Kendra Hockey
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Hafiz Maherali
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Afkhami ME, Almeida BK, Hernandez DJ, Kiesewetter KN, Revillini DP. Tripartite mutualisms as models for understanding plant-microbial interactions. CURRENT OPINION IN PLANT BIOLOGY 2020; 56:28-36. [PMID: 32247158 DOI: 10.1016/j.pbi.2020.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/01/2020] [Accepted: 02/11/2020] [Indexed: 06/11/2023]
Abstract
All plants host diverse microbial assemblages that shape plant health, productivity, and function. While some microbial effects are attributable to particular symbionts, interactions among plant-associated microbes can nonadditively affect plant fitness and traits in ways that cannot be predicted from pairwise interactions. Recent research into tripartite plant-microbe mutualisms has provided crucial insight into this nonadditivity and the mechanisms underlying plant interactions with multiple microbes. Here, we discuss how interactions among microbial mutualists affect plant performance, highlight consequences of biotic and abiotic context-dependency for nonadditive outcomes, and summarize burgeoning efforts to determine the molecular bases of how plants regulate establishment, resource exchange, and maintenance of tripartite interactions. We conclude with four goals for future tripartite studies that will advance our overall understanding of complex plant-microbial interactions.
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Affiliation(s)
- Michelle E Afkhami
- University of Miami, Department of Biology, Coral Gables, FL 33146, USA.
| | - Brianna K Almeida
- University of Miami, Department of Biology, Coral Gables, FL 33146, USA
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7
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Heath KD, Podowski JC, Heniff S, Klinger CR, Burke PV, Weese DJ, Yang WH, Lau JA. Light availability and rhizobium variation interactively mediate the outcomes of legume-rhizobium symbiosis. AMERICAN JOURNAL OF BOTANY 2020; 107:229-238. [PMID: 32072629 DOI: 10.1002/ajb2.1435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/08/2019] [Indexed: 05/22/2023]
Abstract
PREMISE Nutrients, light, water, and temperature are key factors limiting the growth of individual plants in nature. Mutualistic interactions between plants and microbes often mediate resource limitation for both partners. In the mutualism between legumes and rhizobia, plants provide rhizobia with carbon in exchange for fixed nitrogen. Because partner quality in mutualisms is genotype-dependent, within-species genetic variation is expected to alter the responses of mutualists to changes in the resource environment. Here we ask whether partner quality variation in rhizobia mediates the response of host plants to changing light availability, and conversely, whether light alters the expression of partner quality variation. METHODS We inoculated clover hosts with 11 strains of Rhizobium leguminosarum that differed in partner quality, grew plants under either ambient or low light conditions in the greenhouse, and measured plant growth, nodule traits, and foliar nutrient composition. RESULTS Light availability and rhizobium inoculum interactively determined plant growth, and variation in rhizobium partner quality was more apparent in ambient light. CONCLUSIONS Our results suggest that variation in the costs and benefits of rhizobium symbionts mediate host responses to light availability and that rhizobium strain variation might more important in higher-light environments. Our work adds to a growing appreciation for the role of microbial intraspecific and interspecific diversity in mediating extended phenotypes in their hosts and suggests an important role for light availability in the ecology and evolution of legume-rhizobium symbiosis.
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Affiliation(s)
- Katy D Heath
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Justin C Podowski
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Stephanie Heniff
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Christie R Klinger
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Patricia V Burke
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Dylan J Weese
- Department of Biology, St. Ambrose University, Davenport, IA, 52803, USA
| | - Wendy H Yang
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Jennifer A Lau
- W. K. Kellogg Biological Station and Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
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8
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Shaw RG. From the Past to the Future: Considering the Value and Limits of Evolutionary Prediction. Am Nat 2019; 193:1-10. [DOI: 10.1086/700565] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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9
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terHorst CP, Zee PC, Heath KD, Miller TE, Pastore AI, Patel S, Schreiber SJ, Wade MJ, Walsh MR. Evolution in a Community Context: Trait Responses to Multiple Species Interactions. Am Nat 2018. [DOI: 10.1086/695835] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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