1
|
Assour HR, Ashman TL, Turcotte MM. Neopolyploidy-induced changes in giant duckweed (Spirodela polyrhiza) alter herbivore preference and performance and plant population performance. AMERICAN JOURNAL OF BOTANY 2024; 111:e16301. [PMID: 38468124 DOI: 10.1002/ajb2.16301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 03/13/2024]
Abstract
PREMISE Polyploidy is a widespread mutational process in angiosperms that may alter population performance of not only plants but also their interacting species. Yet, knowledge of whether polyploidy affects plant-herbivore dynamics is scarce. Here, we tested whether aphid herbivores exhibit preference for diploid or neopolyploid plants, whether polyploidy impacts plant and herbivore performance, and whether these interactions depend on the plant genetic background. METHODS Using independently synthesized neotetraploid strains paired with their diploid progenitors of greater duckweed (Spirodela polyrhiza), we evaluated the effect of neopolyploidy on duckweed's interaction with the water-lily aphid (Rhopalosiphum nymphaeae). Using paired-choice experiments, we evaluated feeding preference of the herbivore. We then evaluated the consequences of polyploidy on aphid and plant performance by measuring population growth over multiple generations. RESULTS Aphids preferred neopolyploids when plants were provided at equal abundances but not at equal surface areas, suggesting the role of plant population surface area in driving this preference. Additionally, neopolyploidy increased aphid population performance, but this result was dependent on the plant's genetic lineage. Lastly, the impact of herbivory on neopolyploid vs. diploid duckweed varied greatly with genetic lineage, where neopolyploids appeared to be variably tolerant compared to diploids, sometimes mirroring the effect on herbivore performance. CONCLUSIONS By experimentally testing the impacts of polyploidy on trophic species interactions, we showed that polyploidization can impact the preference and performance of herbivores on their plant hosts. These results have significant implications for the establishment and persistence of plants and herbivores in the face of plant polyploidy.
Collapse
Affiliation(s)
- Hannah R Assour
- Department of Biological Sciences, University of Pittsburgh, Dietrich School of Arts and Sciences, Pittsburgh, 15260, PA, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Dietrich School of Arts and Sciences, Pittsburgh, 15260, PA, USA
| | - Martin M Turcotte
- Department of Biological Sciences, University of Pittsburgh, Dietrich School of Arts and Sciences, Pittsburgh, 15260, PA, USA
| |
Collapse
|
2
|
van Mazijk R, West AG, Verboom GA, Elliott TL, Bureš P, Muasya AM. Genome size variation in Cape schoenoid sedges (Schoeneae) and its ecophysiological consequences. AMERICAN JOURNAL OF BOTANY 2024; 111:e16315. [PMID: 38695147 DOI: 10.1002/ajb2.16315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 08/24/2024]
Abstract
PREMISE Increases in genome size in plants-often associated with larger, low-density stomata and greater water-use efficiency (WUE)-could affect plant ecophysiological and hydraulic function. Variation in plant genome size is often due to polyploidy, having occurred repeatedly in the austral sedge genus Schoenus in the Cape Floristic Region (CFR), while species in the other major schoenoid genus in the region, Tetraria, have smaller genomes. Comparing these genera is useful as they co-occur at the landscape level, under broadly similar bioclimatic conditions. We hypothesized that CFR Schoenus have greater WUE, with lower maximum stomatal conductance (gwmax) imposed by larger, less-dense stomata. METHODS We investigated relationships between genome size and stomatal parameters in a phylogenetic context, reconstructing a phylogeny of CFR-occurring Schoeneae (Cyperaceae). Species' stomatal and functional traits were measured from field-collected and herbarium specimens. Carbon stable isotopes were used as an index of WUE. Genome size was derived from flow-cytometric measurements of leafy shoots. RESULTS Evolutionary regressions demonstrated that stomatal size and density covary with genome size, positively and negatively, respectively, with genome size explaining 72-75% of the variation in stomatal size. Larger-genomed species had lower gwmax and C:N ratios, particularly in culms. CONCLUSIONS We interpret differences in vegetative physiology between the genera as evidence of more-conservative strategies in CFR Schoenus compared to the more-acquisitive Tetraria. Because Schoenus have smaller, reduced leaves, they likely rely more on culm photosynthesis than Tetraria. Across the CFR Schoeneae, ecophysiology correlates with genome size, but confounding sources of trait variation limit inferences about causal relationships between traits.
Collapse
Affiliation(s)
- Ruan van Mazijk
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- C4 EcoSolutions, Tokai, Cape Town, 7945, South Africa
| | - Adam G West
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
| | - G Anthony Verboom
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
| | - Tammy L Elliott
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, 611 37, Czech Republic
| | - Petr Bureš
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, 611 37, Czech Republic
| | - A Muthama Muasya
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
| |
Collapse
|
3
|
Christenhusz MJM, Leitch AR, Leitch IJ, Fay MF. The genome sequence of rosebay willowherb Chamaenerion angustifolium (L.) Scop., 1771 (syn. Epilobium angustifolium L., 1753) (Onagraceae). Wellcome Open Res 2024; 9:163. [PMID: 38903872 PMCID: PMC11187524 DOI: 10.12688/wellcomeopenres.21163.1] [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] [Accepted: 03/06/2024] [Indexed: 06/22/2024] Open
Abstract
We present a genome assembly from an individual Chamaenerion angustifolium (fireweed; Tracheophyta; Magnoliopsida; Myrtales; Onagraceae). The genome sequence is 655.9 megabases in span. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 495.18 kilobases and 160.41 kilobases in length, respectively.
Collapse
Affiliation(s)
| | | | | | | | | | - Plant Genome Sizing collective
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Queen Mary University of London, London, England, UK
| | | | - Wellcome Sanger Institute Tree of Life Management, Samples and Laboratory team
- Royal Botanic Gardens Kew, Richmond, England, UK
- Curtin University, Perth, Western Australia, Australia
- Queen Mary University of London, London, England, UK
| | | | | | | | | |
Collapse
|
4
|
Walczyk AM, Hersch-Green EI. Genome-material costs and functional trade-offs in the autopolyploid Solidago gigantea (giant goldenrod) series. AMERICAN JOURNAL OF BOTANY 2023; 110:e16218. [PMID: 37551707 DOI: 10.1002/ajb2.16218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/21/2023] [Accepted: 06/21/2023] [Indexed: 08/09/2023]
Abstract
PREMISE Increased genome-material costs of N and P atoms inherent to organisms with larger genomes have been proposed to limit growth under nutrient scarcities and to promote growth under nutrient enrichments. Such responsiveness may reflect a nutrient-dependent diploid versus polyploid advantage that could have vast ecological and evolutionary implications, but direct evidence that material costs increase with ploidy level and/or influence cytotype-dependent growth, metabolic, and/or resource-use trade-offs is limited. METHODS We grew diploid, autotetraploid, and autohexaploid Solidago gigantea plants with one of four ambient or enriched N:P ratios and measured traits related to material costs, primary and secondary metabolism, and resource-use. RESULTS Relative to diploids, polyploids invested more N and P into cells, and tetraploids grew more with N enrichments, suggesting that material costs increase with ploidy level. Polyploids also generally exhibited strategies that could minimize material-cost constraints over both long (reduced monoploid genome size) and short (more extreme transcriptome downsizing, reduced photosynthesis rates and terpene concentrations, enhanced N-use efficiencies) evolutionary time periods. Furthermore, polyploids had lower transpiration rates but higher water-use efficiencies than diploids, both of which were more pronounced under nutrient-limiting conditions. CONCLUSIONS N and P material costs increase with ploidy level, but material-cost constraints might be lessened by resource allocation/investment mechanisms that can also alter ecological dynamics and selection. Our results enhance mechanistic understanding of how global increases in nutrients might provide a release from material-cost constraints in polyploids that could impact ploidy (or genome-size)-specific performances, cytogeographic patterning, and multispecies community structuring.
Collapse
Affiliation(s)
- Angela M Walczyk
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA
- Biology Department, Gustavus Adolphus College, 800 West College Avenue, St. Peter, MN, 56082, USA
| | - Erika I Hersch-Green
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA
| |
Collapse
|
5
|
Anneberg TJ, O'Neill EM, Ashman TL, Turcotte MM. Polyploidy impacts population growth and competition with diploids: multigenerational experiments reveal key life-history trade-offs. THE NEW PHYTOLOGIST 2023; 238:1294-1304. [PMID: 36740596 DOI: 10.1111/nph.18794] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Ecological theory predicts that early generation polyploids ('neopolyploids') should quickly go extinct owing to the disadvantages of rarity and competition with their diploid progenitors. However, polyploids persist in natural habitats globally. This paradox has been addressed theoretically by recognizing that reproductive assurance of neopolyploids and niche differentiation can promote establishment. Despite this, the direct effects of polyploidy at the population level remain largely untested despite establishment being an intrinsically population-level process. We conducted population-level experiments where life-history investment in current and future growth was tracked in four lineage pairs of diploids and synthetic autotetraploids of the aquatic plant Spirodela polyrhiza. Population growth was evaluated with and without competition between diploids and neopolyploids across a range of nutrient treatments. Although neopolyploid populations produce more biomass, they reach lower population sizes and have reduced carrying capacities when growing alone or in competition across all nutrient treatments. Thus, contrary to individual-level studies, our population-level data suggest that neopolyploids are competitively inferior to diploids. Conversely, neopolyploid populations have greater investment in dormant propagule production than diploids. Our results show that neopolyploid populations should not persist based on current growth dynamics, but high potential future growth may allow polyploids to establish in subsequent seasons.
Collapse
Affiliation(s)
- Thomas J Anneberg
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Elizabeth M O'Neill
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Martin M Turcotte
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| |
Collapse
|
6
|
Elliott TL, Muasya AM, Bureš P. Complex patterns of ploidy in a holocentric plant clade (Schoenus, Cyperaceae) in the Cape biodiversity hotspot. ANNALS OF BOTANY 2023; 131:143-156. [PMID: 35226733 PMCID: PMC9904348 DOI: 10.1093/aob/mcac027] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/27/2022] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS It is unclear how widespread polyploidy is throughout the largest holocentric plant family - the Cyperaceae. Because of the prevalence of chromosomal fusions and fissions, which affect chromosome number but not genome size, it can be impossible to distinguish if individual plants are polyploids in holocentric lineages based on chromosome count data alone. Furthermore, it is unclear how differences in genome size and ploidy levels relate to environmental correlates within holocentric lineages, such as the Cyperaceae. METHODS We focus our analyses on tribe Schoeneae, and more specifically the southern African clade of Schoenus. We examine broad-scale patterns of genome size evolution in tribe Schoeneae and focus more intensely on determining the prevalence of polyploidy across the southern African Schoenus by inferring ploidy level with the program ChromEvol, as well as interpreting chromosome number and genome size data. We further investigate whether there are relationships between genome size/ploidy level and environmental variables across the nutrient-poor and summer-arid Cape biodiversity hotspot. KEY RESULTS Our results show a large increase in genome size, but not chromosome number, within Schoenus compared to other species in tribe Schoeneae. Across Schoenus, there is a positive relationship between chromosome number and genome size, and our results suggest that polyploidy is a relatively common process throughout the southern African Schoenus. At the regional scale of the Cape, we show that polyploids are more often associated with drier locations that have more variation in precipitation between dry and wet months, but these results are sensitive to the classification of ploidy level. CONCLUSIONS Polyploidy is relatively common in the southern African Schoenus, where a positive relationship is observed between chromosome number and genome size. Thus, there may be a high incidence of polyploidy in holocentric plants, whose cell division properties differ from monocentrics.
Collapse
Affiliation(s)
| | - A Muthama Muasya
- Bolus Herbarium, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town 7701, South Africa
| | - Petr Bureš
- Masaryk University, Faculty of Science, Department of Botany and Zoology, Kotlarska 2, Brno, Czech Republic
| |
Collapse
|
7
|
Walczyk AM, Hersch-Green EI. Do water and soil nutrient scarcities differentially impact the performance of diploid and tetraploid Solidago gigantea (Giant Goldenrod, Asteraceae)? PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1031-1042. [PMID: 35727918 DOI: 10.1111/plb.13448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Plants require water and nutrients for survival, although the effects of their availabilities on plant fitness differ amongst species. Genome size variation, within and across species, is suspected to influence plant water and nutrient requirements, but little is known about how variations in these resources concurrently affect plant fitness based on genome size. We examined how genome size variation between autopolyploid cytotypes influences plant morphological and physiological traits, and whether cytotype-specific trait responses differ based on water and/or nutrient availability. Diploid and autotetraploid Solidago gigantea (Giant Goldenrod) were grown in a greenhouse under four soil water:N+P treatments (L:L, L:H, H:L, H:H), and stomata characteristics (size, density), growth (above- and belowground biomass, R/S), and physiological (Anet , E, WUE) responses were measured. Resource availabilities and cytotype identity influenced some plant responses but their effects were independent of each other. Plants grown in high-water and nutrient treatments were larger, plants grown in low-water or high-nutrient treatments had higher WUE but lower E, and Anet and E rates decreased as plants aged. Autotetraploids also had larger and fewer stomata, higher biomass and larger Anet than diploids. Nutrient and water availability could influence intra- and interspecific competitive outcomes. Although S. gigantea cytotypes were not differentially affected by resource treatments, genome size may influence cytogeographic range patterning and population establishment likelihood. For instance, the larger size of autotetraploid S. gigantea might render them more competitive for resources and niche space than diploids.
Collapse
Affiliation(s)
- A M Walczyk
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - E I Hersch-Green
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| |
Collapse
|
8
|
Leitch AR, Leitch IJ. Genome evolution: On the nature of trade-offs with polyploidy and endopolyploidy. Curr Biol 2022; 32:R952-R954. [PMID: 36167043 DOI: 10.1016/j.cub.2022.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A new study uncovers a novel trade-off in polyploid plants. While the larger cells of polyploids benefit from increased cell storage and water retention, this comes at the cost of reduced structural stability, potentially impacting survival.
Collapse
Affiliation(s)
- Andrew R Leitch
- Queen Mary University of London, London, UK. a.r.leitch,@,qmul.ac.uk
| | | |
Collapse
|
9
|
Van Drunen WE, Friedman J. Autopolyploid establishment depends on life-history strategy and the mating outcomes of clonal architecture. Evolution 2022; 76:1953-1970. [PMID: 35861365 DOI: 10.1111/evo.14582] [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: 12/10/2021] [Revised: 06/21/2022] [Accepted: 07/11/2022] [Indexed: 01/22/2023]
Abstract
Polyploidy is a significant component in the evolution of many taxa, particularly plant groups. However, new polyploids face substantial fitness disadvantages due to a lack of same-cytotype mates, and the factors promoting or preventing polyploid establishment in natural populations are often unclear. We develop spatially explicit agent-based simulation models to test the hypothesis that a perennial life history and clonal propagation facilitate the early stages of polyploid establishment and persistence. Our models show that polyploids are more likely to establish when they have longer life spans than diploids, especially when self-fertilization rates are high. Polyploids that combine sexual and clonal reproduction can establish across a wide range of life histories, but their success is moderated by clonal strategy. By tracking individuals and mating events, we reveal that clonal architecture has a substantial impact on the spatial structure of the mixed diploid-polyploid population during polyploid establishment: altering patterns of mating within or between cytotypes via geitonogamous self-fertilization, the mechanisms through which polyploid establishment proceeds, and the final composition of the polyploid population. Overall, our findings provide novel insight into the role of clonal structure in modulating the complex relationship between polyploidy, perenniality, and clonality and offer testable predictions for future empirical work.
Collapse
Affiliation(s)
- Wendy E Van Drunen
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.,Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Jannice Friedman
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| |
Collapse
|
10
|
Faizullah L, Morton JA, Hersch-Green EI, Walczyk AM, Leitch AR, Leitch IJ. Exploring environmental selection on genome size in angiosperms. TRENDS IN PLANT SCIENCE 2021; 26:1039-1049. [PMID: 34219022 DOI: 10.1016/j.tplants.2021.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 05/22/2023]
Abstract
Angiosperms show a remarkable range in genome size (GS), yet most species have small genomes, despite the frequency of polyploidy and repeat amplification in the ancestries of most lineages. It has been suggested that larger genomes incur costs that have driven selection for GS reduction, although the nature of these costs and how they might impact selection remain unclear. We explore potential costs of increased GS encompassing impacts on minimum cell size with consequences for photosynthesis and water-use efficiency and effects of greater nitrogen and phosphorus demands of the nucleus leading to more severe trade-offs with photosynthesis. We suggest that nutrient-, water-, and/or CO2-stressed conditions might favour species with smaller genomes, with implications for species' ecological and evolutionary dynamics.
Collapse
Affiliation(s)
- Lubna Faizullah
- Character Evolution Team, Royal Botanic Gardens, Kew, Richmond, Surrey, UK; School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, UK
| | - Joseph A Morton
- Character Evolution Team, Royal Botanic Gardens, Kew, Richmond, Surrey, UK; School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, UK
| | - Erika I Hersch-Green
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Angela M Walczyk
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, UK.
| | - Ilia J Leitch
- Character Evolution Team, Royal Botanic Gardens, Kew, Richmond, Surrey, UK.
| |
Collapse
|
11
|
Wang X, Morton JA, Pellicer J, Leitch IJ, Leitch AR. Genome downsizing after polyploidy: mechanisms, rates and selection pressures. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1003-1015. [PMID: 34077584 DOI: 10.1111/tpj.15363] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 05/20/2023]
Abstract
An analysis of over 10 000 plant genome sizes (GSs) indicates that most species have smaller genomes than expected given the incidence of polyploidy in their ancestries, suggesting selection for genome downsizing. However, comparing ancestral GS with the incidence of ancestral polyploidy suggests that the rate of DNA loss following polyploidy is likely to have been very low (4-70 Mb/million years, 4-482 bp/generation). This poses a problem. How might such small DNA losses be visible to selection, overcome the power of genetic drift and drive genome downsizing? Here we explore that problem, focussing on the role that double-strand break (DSB) repair pathways (non-homologous end joining and homologous recombination) may have played. We also explore two hypotheses that could explain how selection might favour genome downsizing following polyploidy: to reduce (i) nitrogen (N) and phosphate (P) costs associated with nucleic acid synthesis in the nucleus and the transcriptome and (ii) the impact of scaling effects of GS on cell size, which influences CO2 uptake and water loss. We explore the hypothesis that losses of DNA must be fastest in early polyploid generations. Alternatively, if DNA loss is a more continuous process over evolutionary time, then we propose it is a byproduct of selection elsewhere, such as limiting the damaging activity of repetitive DNA. If so, then the impact of GS on photosynthesis, water use efficiency and/or nutrient costs at the nucleus level may be emergent properties, which have advantages, but not ones that could have been selected for over generational timescales.
Collapse
Affiliation(s)
- Xiaotong Wang
- Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Joseph A Morton
- Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Jaume Pellicer
- Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Passeig del Migdia sn, Barcelona, 08038, Spain
| | | | - Andrew R Leitch
- Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| |
Collapse
|
12
|
Han TS, Zheng QJ, Onstein RE, Rojas-Andrés BM, Hauenschild F, Muellner-Riehl AN, Xing YW. Polyploidy promotes species diversification of Allium through ecological shifts. THE NEW PHYTOLOGIST 2020; 225:571-583. [PMID: 31394010 DOI: 10.1111/nph.16098] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/01/2019] [Indexed: 05/14/2023]
Abstract
Despite the role of polyploidy in multiple evolutionary processes, its impact on plant diversification remains controversial. An increased polyploid frequency may facilitate speciation through shifts in ecology, morphology or both. Here we used Allium to evaluate: (1) the relationship between intraspecific polyploid frequency and species diversification rate; and (2) whether this process is associated with habitat and/or trait shifts. Using eight plastid and nuclear ribosomal markers, we built a phylogeny of 448 Allium species, representing 46% of the total. We quantified intraspecific ploidy diversity, heterogeneity in diversification rates and their relationship along the phylogeny using trait-dependent diversification models. Finally, we evaluated the association between polyploidisation and habitat or trait shifts. We detected high ploidy diversity in Allium and a polyploidy-related diversification rate shift with a probability of 95% in East Asia. Allium lineages with high polyploid frequencies had higher species diversification rates than those of diploids or lineages with lower polyploid frequencies. Shifts in speciation rates were strongly correlated with habitat shifts linked to particular soil conditions; 81.7% of edaphic variation could be explained by polyploidisation. Our study emphasises the role of intraspecific polyploid frequency combined with ecological drivers on Allium diversification, which may explain plant radiations more generally.
Collapse
Affiliation(s)
- Ting-Shen Han
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA
| | - Quan-Jing Zheng
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Renske E Onstein
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, D-04103, Germany
| | - Blanca M Rojas-Andrés
- Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Leipzig University, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Frank Hauenschild
- Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Leipzig University, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Alexandra N Muellner-Riehl
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, D-04103, Germany
- Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Leipzig University, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Yao-Wu Xing
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| |
Collapse
|