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McDaniel SF. Local adaptation, recombination, and the fate of neopolyploids. THE NEW PHYTOLOGIST 2024; 244:32-38. [PMID: 39045612 DOI: 10.1111/nph.20011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 07/09/2024] [Indexed: 07/25/2024]
Abstract
Polyploidy is widely recognized as an important speciation mechanism because it isolates tetraploids from their diploid progenitors. Polyploidy also provides new genetic material that may facilitate adaptive evolution. However, new mutations are more likely to arise after a neopolyploid has already successfully invaded a population. Thus, the role of adaptive forces in establishing a polyploid remains unclear. One solution to this apparent paradox may lie in the capacity of polyploids to suppress recombination among preexisting locally adapted alleles. The local adaptation mechanism requires that spatially heterogeneous selection acts on multiple loci and that gene flow introduces maladapted alleles to the population where the polyploid forms. The mechanism requires neither strong genetic drift nor any intrinsic benefit of genome doubling and can accommodate any mode of gene action. A unique prediction of the mechanism is that adaptive alleles should predate polyploidization, a pattern consistent with observations from a few well-studied polyploids. The mechanism is also consistent with the coexistence of both diploid and tetraploid cytotypes, fitness heterogeneity among independently derived polyploids, and the prevalence of outcrossing among older polyploids. The local adaptation mechanism also makes novel predictions about circumstances favoring polyploid invasions that can be tested using molecular genetic or comparative approaches.
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Affiliation(s)
- Stuart F McDaniel
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
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2
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Marks RA, Delgado P, Makonya GM, Cooper K, VanBuren R, Farrant JM. Higher order polyploids exhibit enhanced desiccation tolerance in the grass Microchloa caffra. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3612-3623. [PMID: 38511472 PMCID: PMC11156804 DOI: 10.1093/jxb/erae126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 03/15/2024] [Indexed: 03/22/2024]
Abstract
Desiccation tolerance evolved recurrently across diverse plant lineages to enable survival in water-limited conditions. Many resurrection plants are polyploid, and several groups have hypothesized that polyploidy contributed to the evolution of desiccation tolerance. However, due to the vast phylogenetic distance between resurrection plant lineages, the rarity of desiccation tolerance, and the prevalence of polyploidy in plants, this hypothesis has been difficult to test. Here, we surveyed natural variation in morphological, reproductive, and desiccation tolerance traits across several cytotypes of a single species to test for links between polyploidy and increased resilience. We sampled multiple natural populations of the resurrection grass Microchloa caffra across an environmental gradient ranging from mesic to xeric in South Africa. We describe two distinct ecotypes of M. caffra that occupy different extremes of the environmental gradient and exhibit consistent differences in ploidy, morphological, reproductive, and desiccation tolerance traits in both field and common growth conditions. Interestingly, plants with more polyploid genomes exhibited consistently higher recovery from desiccation, were less reproductive, and were larger than plants with smaller genomes and lower ploidy. These data indicate that selective pressures in increasingly xeric sites may play a role in maintaining and increasing desiccation tolerance and are mediated by changes in ploidy.
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Affiliation(s)
- Rose A Marks
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Paula Delgado
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Givemore Munashe Makonya
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
- Washington State University, Irrigated Agriculture Research and Extension Centre, Prosser, WA 99350, USA
| | - Keren Cooper
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Robert VanBuren
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
| | - Jill M Farrant
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
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Blischak PD, Sajan M, Barker MS, Gutenkunst RN. Demographic history inference and the polyploid continuum. Genetics 2023; 224:iyad107. [PMID: 37279657 PMCID: PMC10411560 DOI: 10.1093/genetics/iyad107] [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: 04/17/2023] [Revised: 04/17/2023] [Accepted: 05/18/2023] [Indexed: 06/08/2023] Open
Abstract
Polyploidy is an important generator of evolutionary novelty across diverse groups in the Tree of Life, including many crops. However, the impact of whole-genome duplication depends on the mode of formation: doubling within a single lineage (autopolyploidy) versus doubling after hybridization between two different lineages (allopolyploidy). Researchers have historically treated these two scenarios as completely separate cases based on patterns of chromosome pairing, but these cases represent ideals on a continuum of chromosomal interactions among duplicated genomes. Understanding the history of polyploid species thus demands quantitative inferences of demographic history and rates of exchange between subgenomes. To meet this need, we developed diffusion models for genetic variation in polyploids with subgenomes that cannot be bioinformatically separated and with potentially variable inheritance patterns, implementing them in the dadi software. We validated our models using forward SLiM simulations and found that our inference approach is able to accurately infer evolutionary parameters (timing, bottleneck size) involved with the formation of auto- and allotetraploids, as well as exchange rates in segmental allotetraploids. We then applied our models to empirical data for allotetraploid shepherd's purse (Capsella bursa-pastoris), finding evidence for allelic exchange between the subgenomes. Taken together, our model provides a foundation for demographic modeling in polyploids using diffusion equations, which will help increase our understanding of the impact of demography and selection in polyploid lineages.
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Affiliation(s)
- Paul D Blischak
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
- Bayer Crop Science, Chesterfield, MO 63017, USA
| | - Mathews Sajan
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Michael S Barker
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Ryan N Gutenkunst
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
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Mata JK, Martin SL, Smith TW. Global biodiversity data suggest allopolyploid plants do not occupy larger ranges or harsher conditions compared with their progenitors. Ecol Evol 2023; 13:e10231. [PMID: 37600489 PMCID: PMC10433117 DOI: 10.1002/ece3.10231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 08/22/2023] Open
Abstract
Understanding the factors determining species' geographical and environmental range is a central question in evolution and ecology, and key for developing conservation and management practices. Shortly after the discovery of polyploidy, just over 100 years ago, it was suggested that polyploids generally have greater range sizes and occur in more extreme conditions than their diploid congeners. This suggestion is now widely accepted in the literature and is attributed to polyploids having an increased capacity for genetic diversity that increases their potential for adaptation and invasiveness. However, the data supporting this idea are mixed. Here, we compare the niche of allopolyploid plants to their progenitor species to determine whether allopolyploidization is associated with increased geographic range or extreme environmental tolerance. Our analysis includes 123 allopolyploid species that exist as only one known ploidy level, with at least one known progenitor species, and at least 50 records in the Global Biodiversity Information Facility (GBIF) database. We used GBIF occurrence data and range modeling tools to quantify the geographic and environmental distribution of these allopolyploids relative to their progenitors. We find no indication that allopolyploid plants occupy more extreme conditions or larger geographic ranges than their progenitors. Data evaluated here generally indicate no significant difference in range between allopolyploids and progenitors, and where significant differences do occur, the progenitors are more likely to exist in extreme conditions. We concluded that the evidence from these data indicate allopolyploidization does not result in larger or more extreme ranges. Thus, allopolyploidization does not have a consistent effect on species distribution, and we conclude it is more likely the content of an allopolyploid's genome rather than polyploidy per se that determines the potential for invasiveness.
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Clo J, Padilla-García N, Kolář F. Polyploidization as an opportunistic mutation: The role of unreduced gametes formation and genetic drift in polyploid establishment. J Evol Biol 2022; 35:1099-1109. [PMID: 35770884 DOI: 10.1111/jeb.14055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/07/2022] [Indexed: 01/17/2023]
Abstract
It is broadly assumed that polyploidy success reflects an increase in fitness associated with whole-genome duplication (WGD), due to higher tolerance to stressful conditions. Nevertheless, WGD also arises with several costs in neo-polyploid lineages, like genomic instability, or cellular mis-management. In addition to these costs, neo-polyploid individuals also face frequency dependent selection because of frequent low-fitness triploids formed by cross-ploidy pollinations when tetraploids are primarily rare in the population. Interestingly, the idea that polyploidy can be fixed by genetic drift as a neutral or deleterious mutation is currently underexplored in the literature. To test how and when polyploidy can fix in a population by chance, we built a theoretical model in which autopolyploidization occurs through the production of unreduced gametes, a trait modelled as a quantitative trait that is allowed to vary through time. We found that when tetraploid individuals are less or as fit as their diploid progenitors, fixation of polyploidy is only possible when genetic drift is stronger than natural selection. The necessity of drift for tetraploid fixation holds even when polyploidy confers a selective advantage, except for scenarios where tetraploids are much fitter than diploids. Finally, we found that self-fertilization is less beneficial for tetraploid establishment than previously thought, notably when polyploids harbour an initial decrease in fitness. Our results bring a novel, non-exclusive explanation for the unequal temporal and spatial distribution of polyploid species.
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Affiliation(s)
- Josselin Clo
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nélida Padilla-García
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Prague, Czech Republic
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Więcław H, Szenejko M, Kull T, Sotek Z, Rębacz-Maron E, Koopman J. Morphological variability and genetic diversity in Carex buxbaumii and Carex hartmaniorum (Cyperaceae) populations. PeerJ 2021; 9:e11372. [PMID: 34026355 PMCID: PMC8121068 DOI: 10.7717/peerj.11372] [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: 09/10/2020] [Accepted: 04/07/2021] [Indexed: 11/20/2022] Open
Abstract
Background Carex buxbaumii and C. hartmaniorum are sister species of the clade Papilliferae within the monophyletic section Racemosae. An unambiguous identification of these species is relatively difficult due to the interspecific continuum of some morphological characters as well as the intraspecific variability. The study was aimed at determining the range of variability, both morphological and genetic, within and between these two closely related and similar species. Methods The sedges were collected during botanical expeditions to Armenia, Estonia, the Netherlands, and Poland. The morphological separation of the two species and their populations was tested using the Discriminant Function Analysis (DFA). The genetic variability of the 19 Carex populations was assessed in the presence of eight Inter Simple Sequence Repeat (ISSR) primers. Results Results of the study indicate a considerable genetic affinity between the two sedge species (mean Si = 0.619). However, the populations of C. hartmaniorum are, morphologically and genetically, more homogenous than the populations of C. buxbaumii. Compared to C. hartmaniorum, C. buxbaumii usually has wider leaf blades, a shorter inflorescence, a lower number of spikes which are shorter, but wider, and longer bracts and utricles. The AMOVA showed a larger variation between the populations of C. buxbaumii, representing 25.65% of the total variation in the taxon. Two populations of C. buxbaumii (from Poland and Estonia) are separated from the remaining populations, both genetically and morphologically; their individuals show shorter utricles and glumes, compared to the typical specimens of C. buxbaumii, and correspond with the morphology of putative infraspecific taxa described by Cajander (var. brevisquamosa and var. confusa). Conclusions The taxonomic status of the putative infraspecific taxa within C. buxbaumii requires further studies throughout the distribution range of C. buxbaumii, addressing habitats, morphology and genetics (including a chromosome count or a combination of different genetic methods), particularly as the variability in C. buxbaumii may be associated with the species’ polyploid origin.
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Affiliation(s)
- Helena Więcław
- Institute of Marine and Environmental Sciences, University of Szczecin, Szczecin, Poland
| | - Magdalena Szenejko
- Institute of Marine and Environmental Sciences, University of Szczecin, Szczecin, Poland.,Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, Poland
| | - Thea Kull
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Zofia Sotek
- Institute of Marine and Environmental Sciences, University of Szczecin, Szczecin, Poland
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Laport RG, Minckley RL, Pilson D. Pollinator assemblage and pollen load differences on sympatric diploid and tetraploid cytotypes of the desert-dominant Larrea tridentata. AMERICAN JOURNAL OF BOTANY 2021; 108:297-308. [PMID: 33580499 PMCID: PMC7986067 DOI: 10.1002/ajb2.1605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 09/21/2020] [Indexed: 06/12/2023]
Abstract
PREMISE Whole-genome duplication (polyploidy) is an important force shaping flowering-plant evolution. Ploidy-specific plant-pollinator interactions represent important community-level biotic interactions that can lead to nonrandom mating and the persistence of mixed-ploidy populations. METHODS At a naturally occurring diploid-tetraploid contact zone of the autopolyploid desert shrub Larrea tridentata, we combined flower phenology analyses, collections of bees on plants of known cytotype, and flow cytometry analyses of bee-collected pollen loads to investigate whether (1) diploid and tetraploid plants have unique bee pollinator assemblages, (2) bee taxa exhibit ploidy-specific visitation and pollen collection biases, and (3) specialist and generalist bee taxa have ploidy-specific visitation and pollen collection biases. RESULTS Although bee assemblages overlapped, we found significant differences in bee visitation to co-occurring diploids and tetraploids, with the introduced honeybee (Apis mellifera) and one native species (Andrena species 12) more frequently visiting tetraploids. Consistent with bee assemblage differences, we found that diploid pollen was overrepresented among pollen loads on native bees, while pollen loads on A. mellifera did not deviate from the random expectation. However, mismatches between the ploidy of pollen loads and plants were common, consistent with ongoing intercytotype gene flow. CONCLUSIONS Our data are consistent with cytotype-specific bee visitation and suggest that pollinator behavior contributes to reduced diploid-tetraploid mating. Differences in bee visitation and pollen movement potentially contribute to an easing of minority cytotype exclusion and the facilitation of cytotype co-occurrence.
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Affiliation(s)
| | | | - Diana Pilson
- School of Biological SciencesUniversity of Nebraska‐LincolnLincolnNE68588USA
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Levin DA. Propagule pressure and the establishment of emergent polyploid populations. ANNALS OF BOTANY 2021; 127:1-5. [PMID: 33106838 PMCID: PMC7750715 DOI: 10.1093/aob/mcaa187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 05/16/2023]
Abstract
BACKGROUND Whereas the incidence or rate of polyploid speciation in flowering plants is modest, the production of polyploid individuals within local populations is widespread. Explanations for this disparity primarily have focused on properties or interactions of polyploids that limit their persistence. HYPOTHESIS The emergence of local polyploid populations within diploid populations is similar to the arrival of invasive species at new, suitable sites, with the exception that polyploids suffer interference from their progenitor(s). The most consistent predictor of successful colonization by invasive plants is propagule pressure, i.e. the number of seeds introduced. Therefore, insufficient propagule pressure, i.e. the formation of polyploid seeds within diploid populations, ostensibly is a prime factor limiting the establishment of newly emergent polyploids within local populations. Increasing propagule number reduces the effects of genetic, environmental and demographic stochasticity, which thwart population survival. As with invasive species, insufficient seed production within polyploid populations limits seed export, and thus reduces the chance of polyploid expansion. CONCLUSION The extent to which propagule pressure limits the establishment of local polyploid populations remains to be determined, because we know so little. The numbers of auto- or allopolyploid seed in diploid populations rarely have been ascertained, as have the numbers of newly emergent polyploid plants within diploid populations. Moreover, seed production by these polyploids has yet to be assessed.
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Affiliation(s)
- Donald A Levin
- Department of Integrative Biology, University of Texas, Austin, TX, USA
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9
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Forrester NJ, Rebolleda-Gómez M, Sachs JL, Ashman TL. Polyploid plants obtain greater fitness benefits from a nutrient acquisition mutualism. THE NEW PHYTOLOGIST 2020; 227:944-954. [PMID: 32248526 DOI: 10.1111/nph.16574] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
Polyploidy is a key driver of ecological and evolutionary processes in plants, yet little is known about its effects on biotic interactions. This gap in knowledge is especially profound for nutrient acquisition mutualisms, despite the fact that they regulate global nutrient cycles and structure ecosystems. Generalism in mutualistic interactions depends on the range of potential partners (niche breadth), the benefits obtained and ability to maintain benefits across a variety of partners (fitness plasticity). Here, we determine how each of these is influenced by polyploidy in the legume-rhizobium mutualism. We inoculated a broad geographic sample of natural diploid and autotetraploid alfalfa (Medicago sativa) lineages with a diverse panel of Sinorhizobium bacterial symbionts. To analyze the extent and mechanism of generalism, we measured host growth benefits and functional traits. Autotetraploid plants obtained greater fitness enhancement from mutualistic interactions and were better able to maintain this across diverse rhizobial partners (i.e. low plasticity in fitness) relative to diploids. These benefits were not attributed to increases in niche breadth, but instead reflect increased rewards from investment in the mutualism. Polyploid plants displayed greater generalization in bacterial mutualisms relative to diploids, illustrating another axis of advantage for polyploids over diploids.
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Affiliation(s)
- Nicole J Forrester
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Ave., Pittsburgh, PA, 15260, USA
| | - Maria Rebolleda-Gómez
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Ave., Pittsburgh, PA, 15260, USA
| | - Joel L Sachs
- Department of Evolution, Ecology, and Organismal Biology, University of California, 3401 Watkins Drive, Riverside, CA, 92521, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Ave., Pittsburgh, PA, 15260, USA
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Sheth SN, Morueta-Holme N, Angert AL. Determinants of geographic range size in plants. THE NEW PHYTOLOGIST 2020; 226:650-665. [PMID: 31901139 DOI: 10.1111/nph.16406] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Geographic range size has long fascinated ecologists and evolutionary biologists, yet our understanding of the factors that cause variation in range size among species and across space remains limited. Not only does geographic range size inform decisions about the conservation and management of rare and nonindigenous species due to its relationship with extinction risk, rarity, and invasiveness, but it also provides insights into fundamental processes such as dispersal and adaptation. There are several features unique to plants (e.g. polyploidy, mating system, sessile habit) that may lead to distinct mechanisms explaining variation in range size. Here, we highlight key studies testing intrinsic and extrinsic hypotheses about geographic range size under contrasting scenarios where species' ranges are static or change over time. We then present results from a meta-analysis of the relative importance of commonly hypothesized determinants of range size in plants. We show that our ability to infer the relative importance of these determinants is limited, particularly for dispersal ability, mating system, ploidy, and environmental heterogeneity. We highlight avenues for future research that merge approaches from macroecology and evolutionary ecology to better understand how adaptation and dispersal interact to facilitate niche evolution and range expansion.
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Affiliation(s)
- Seema Nayan Sheth
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Naia Morueta-Holme
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Amy L Angert
- Departments of Botany and Zoology and Biodiversity Research Centre, University of British Columbia, 3520-6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
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Decanter L, Colling G, Elvinger N, Heiðmarsson S, Matthies D. Ecological niche differences between two polyploid cytotypes of Saxifraga rosacea. AMERICAN JOURNAL OF BOTANY 2020; 107:423-435. [PMID: 32067225 PMCID: PMC7216898 DOI: 10.1002/ajb2.1431] [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: 07/18/2019] [Accepted: 12/04/2019] [Indexed: 05/30/2023]
Abstract
PREMISE Different cytotypes of a species may differ in their morphology, phenology, physiology, and their tolerance of extreme environments. We studied the ecological niches of two subspecies of Saxifraga rosacea with different ploidy levels: the hexaploid Central European endemic subspecies sponhemica and the more widely distributed octoploid subspecies rosacea. METHODS For both cytotypes, we recorded local environmental conditions and mean plant trait values in populations across their areas of distribution, analyzed their distributions by niche modeling, studied their performance at two transplant sites with contrasting conditions, and experimentally tested their cold resistance. RESULTS Mean annual temperature was higher in hexaploid than in octoploid populations and experiments indicated that frost tolerance of the hexaploid is lower than that of the octoploid. Reproduction of octoploids from Central Europe was higher than that of hexaploids at a transplant site in subarctic Iceland, whereas the opposite was true in temperate Luxembourg, indicating adaptation of the octoploids to colder conditions. Temperature variables were also most important in niche models predicting the distribution of the two cytotypes. Genetic differences in survival among populations were larger for the octoploids than for the hexaploids in both field gardens, suggesting that greater genetic variability may contribute to the octoploid's larger distributional range. CONCLUSIONS Our results support the hypotheses that different cytotypes may have different niches leading to spatial segregation, and that higher ploidy levels can result in a broader ecological niche and greater tolerance of more extreme conditions.
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Affiliation(s)
- Lucile Decanter
- Fondation Faune‐Flore c/o Musée national d'histoire naturelle25 rue MünsterL‐2160LuxembourgLuxembourg
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
- Unit of Plant EcologyDepartment of BiologyUniversity of MarburgKarl‐von‐Frisch‐Straße 8D‐35043MarburgGermany
| | - Guy Colling
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
| | - Nora Elvinger
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
| | - Starri Heiðmarsson
- The Icelandic Institute of Natural HistoryBorgir vid Nordurslod600AkureyriIceland
| | - Diethart Matthies
- Unit of Plant EcologyDepartment of BiologyUniversity of MarburgKarl‐von‐Frisch‐Straße 8D‐35043MarburgGermany
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12
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Pangua E, Pajarón S, Quintanilla LG. Fitness of an allopolyploid rupicolous fern compared with its diploid progenitors: from sporogenesis to sporophyte formation. AMERICAN JOURNAL OF BOTANY 2019; 106:984-995. [PMID: 31188481 DOI: 10.1002/ajb2.1314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
PREMISE When two populations of related cytotypes grow in sympatry, the rarer cytotype tends to be excluded due to a frequency-dependent mating disadvantage. Evolutionary models predict that polyploids, which are typically the rarer cytotype upon first formation, should have higher relative fitness and/or higher selfing rates to establish and then coexist with diploid parents. METHODS Performance during early recruitment was compared among three co-occurring rupicolous fern species: the allotetraploid Cheilanthes tinaei and its diploid ancestors, C. hispanica and C. maderensis. In culture experiments, fresh spores and samples of soil spore banks were tested for variation among cytotypes in germination, survival, fecundity, and mating system of gametophytes. RESULTS Compared with its diploid parents, C. tinaei fresh spores had higher abortion percentages, lower dispersal ability as a result of its larger spores, and similar vigor at germination. For gametophytes from soil spore banks, C. tinaei had high survival similar to C. maderensis, but its sex expression resembled that of C. hispanica, with a high proportion of males. Patterns of sporophyte formation by females and bisexuals indicate that the polyploid does not have an increased gametophytic selfing rate. Gametophytes were larger in C. tinaei, but its reproductive success (sporophyte formation) was intermediate relative to diploids. CONCLUSIONS Our results show no evidence of higher selfing or fitness advantage of the allopolyploid over both diploid parents at any stage of early recruitment. These two unexpected findings suggest that further factors, such as niche differentiation, play a more important role in cytotype coexistence.
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Affiliation(s)
- Emilia Pangua
- Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense, Madrid, E-28040, Spain
| | - Santiago Pajarón
- Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense, Madrid, E-28040, Spain
| | - Luis G Quintanilla
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, Móstoles, E-28933, Spain
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López-Jurado J, Mateos-Naranjo E, Balao F. Niche divergence and limits to expansion in the high polyploid Dianthus broteri complex. THE NEW PHYTOLOGIST 2019; 222:1076-1087. [PMID: 30585629 DOI: 10.1111/nph.15663] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/14/2018] [Indexed: 05/25/2023]
Abstract
Niche evolution in plant polyploids remains controversial and evidence for alternative patterns has been reported. Using the autopolyploid Dianthus broteri complex (2×, 4×, 6× and 12×) as a model, we aimed to integrate three scenarios - competitive exclusion, recurrent origins of cytotypes and niche filling - into a single framework of polyploid niche evolution. We hypothesized that high polyploids would tend to evolve towards extreme niches when low ploidy cytotypes have nearly filled the niche space. We used several ecoinformatics and phylogenetic comparative analyses to quantify differences in the ecological niche of each cytotype and to evaluate alternative models of niche evolution. Each cytotype in this complex occupied a distinct ecological niche. The distributions were mainly constrained by soil characteristics, temperature and drought stress imposed by the Mediterranean climate. Tetraploids had the highest niche breadth and overlap due to their multiple origins, whereas the higher ploidy cytotypes were found in different, restricted, nonoverlapping niches. Niche evolution analyses suggested a scenario with one niche optimum for each ploidy, including the two independent tetraploid lineages. Our results suggest that the fate of nascent polyploids could not be predicted without accounting for phylogenetic relatedness, recurrent origins or the niche occupied by ancestors.
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Affiliation(s)
- Javier López-Jurado
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, E-41080, Seville, Spain
| | - Enrique Mateos-Naranjo
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, E-41080, Seville, Spain
| | - Francisco Balao
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, E-41080, Seville, Spain
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Wei N, Cronn R, Liston A, Ashman T. Functional trait divergence and trait plasticity confer polyploid advantage in heterogeneous environments. THE NEW PHYTOLOGIST 2019; 221:2286-2297. [PMID: 30281801 PMCID: PMC6587808 DOI: 10.1111/nph.15508] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/24/2018] [Indexed: 05/09/2023]
Abstract
Polyploidy, or whole-genome duplication often with hybridization, is common in eukaryotes and is thought to drive ecological and evolutionary success, especially in plants. The mechanisms of polyploid success in ecologically relevant contexts, however, remain largely unknown. We conducted an extensive test of functional trait divergence and plasticity in conferring polyploid fitness advantage in heterogeneous environments, by growing clonal replicates of a worldwide genotype collection of six allopolyploid and five diploid wild strawberry (Fragaria) taxa in three climatically different common gardens. Among leaf functional traits, we detected divergence in trait means but not plasticities between polyploids and diploids, suggesting that increased genomic redundancy in polyploids does not necessarily translate into greater trait plasticity in response to environmental change. Across the heterogeneous garden environments, however, polyploids exhibited fitness advantage, which was conferred by both trait means and adaptive trait plasticities, supporting a 'jack-and-master' hypothesis for polyploids. Our findings elucidate essential ecological mechanisms underlying polyploid adaptation to heterogeneous environments, and provide an important insight into the prevalence and persistence of polyploid plants.
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Affiliation(s)
- Na Wei
- Department of Biological SciencesUniversity of PittsburghPittsburghPA15260USA
| | - Richard Cronn
- Pacific Northwest Research StationUnited States Department of Agriculture Forest ServiceCorvallisOR97331USA
| | - Aaron Liston
- Department of Botany and Plant PathologyOregon State UniversityCorvallisOR97331USA
| | - Tia‐Lynn Ashman
- Department of Biological SciencesUniversity of PittsburghPittsburghPA15260USA
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15
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Carta A, Bedini G, Peruzzi L. Unscrambling phylogenetic effects and ecological determinants of chromosome number in major angiosperm clades. Sci Rep 2018; 8:14258. [PMID: 30250220 PMCID: PMC6155329 DOI: 10.1038/s41598-018-32515-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 09/10/2018] [Indexed: 11/09/2022] Open
Abstract
As variations in the chromosome number are recognized to be of evolutionary interest but are also widely debated in the literature, we aimed to quantitatively test for possible relationships among the chromosome number, plant traits, and environmental factors. In particular, the chromosome number and drivers of its variation were examined in 801 Italian endemic vascular plants, for a total of 1364 accessions. We estimated phylogenetic inertia and adaptation in chromosome number - based on an Ornstein-Uhlenbeck process - and related chromosome numbers with other plant traits and environmental variables. Phylogenetic effects in chromosome number varied among the examined clades but were generally high. Chromosome numbers were poorly related to large scale climatic conditions, while a stronger relationship with categorical variables was found. Specifically, open, disturbed, drought-prone habitats selected for low chromosome numbers, while perennial herbs, living in shaded, stable environments were associated with high chromosome numbers. Altogether, our findings support an evolutionary role of chromosome number variation, and we argue that environmental stability favours higher recombination rates in comparison to unstable environments. In addition, by comparing the results of models testing for the evolvability of 2n and of x, we provide insight into the presumptive ecological significance of polyploidy.
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Affiliation(s)
- Angelino Carta
- Department of Biology, Unit of Botany, University of Pisa, via Derna 1, 56126, Pisa, Italy.
| | - Gianni Bedini
- Department of Biology, Unit of Botany, University of Pisa, via Derna 1, 56126, Pisa, Italy
| | - Lorenzo Peruzzi
- Department of Biology, Unit of Botany, University of Pisa, via Derna 1, 56126, Pisa, Italy
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16
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Gaynor ML, Ng J, Laport RG. Phylogenetic Structure of Plant Communities: Are Polyploids Distantly Related to Co-occurring Diploids? Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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Novikova PY, Hohmann N, Van de Peer Y. Polyploid Arabidopsis species originated around recent glaciation maxima. CURRENT OPINION IN PLANT BIOLOGY 2018; 42:8-15. [PMID: 29448159 DOI: 10.1016/j.pbi.2018.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/17/2018] [Indexed: 05/20/2023]
Abstract
Polyploidy may provide adaptive advantages and is considered to be important for evolution and speciation. Polyploidy events are found throughout the evolutionary history of plants, however they do not seem to be uniformly distributed along the time axis. For example, many of the detected ancient whole-genome duplications (WGDs) seem to cluster around the K/Pg boundary (∼66Mya), which corresponds to a drastic climate change event and a mass extinction. Here, we discuss more recent polyploidy events using Arabidopsis as the most developed plant model at the level of the entire genus. We review the history of the origin of allotetraploid species A. suecica and A. kamchatica, and tetraploid lineages of A. lyrata, A. arenosa and A. thaliana, and discuss potential adaptive advantages. Also, we highlight an association between recent glacial maxima and estimated times of origins of polyploidy in Arabidopsis. Such association might further support a link between polyploidy and environmental challenge, which has been observed now for different time-scales and for both ancient and recent polyploids.
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Affiliation(s)
- Polina Yu Novikova
- VIB-UGent Center for Plant Systems Biology, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Nora Hohmann
- University of Basel, Department of Environmental Sciences, Basel, Switzerland
| | - Yves Van de Peer
- VIB-UGent Center for Plant Systems Biology, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; Bioinformatics Institute Ghent, Ghent University, Ghent, Belgium; Department of Genetics, University of Pretoria, Pretoria, South Africa.
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