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Jhajhariya M, Mangla Y, Chandra A, Goel S, Tandon R. Variable resource allocation pattern, biased sex-ratio, and extent of sexual dimorphism in subdioecious Hippophae rhamnoides. PLoS One 2024; 19:e0302211. [PMID: 38635726 PMCID: PMC11025892 DOI: 10.1371/journal.pone.0302211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/30/2024] [Indexed: 04/20/2024] Open
Abstract
Evolutionary maintenance of dioecy is a complex phenomenon and varies by species and underlying pathways. Also, different sexes may exhibit variable resource allocation (RA) patterns among the vegetative and reproductive functions. Such differences are reflected in the extent of sexual dimorphism. Though rarely pursued, investigation on plant species harbouring intermediate sexual phenotypes may reveal useful information on the strategy pertaining to sex-ratios and evolutionary pathways. We studied H. rhamnoides ssp. turkestanica, a subdioecious species with polygamomonoecious (PGM) plants, in western Himalaya. The species naturally inhabits a wide range of habitats ranging from river deltas to hill slopes. These attributes of the species are conducive to test the influence of abiotic factors on sexual dimorphism, and RA strategy among different sexes. The study demonstrates sexual dimorphism in vegetative and reproductive traits. The sexual dimorphism index, aligned the traits like height, number of branches, flower production, and dry-weight of flowers with males while others including fresh-weight of leaves, number of thorns, fruit production were significantly associated with females. The difference in RA pattern is more pronounced in reproductive traits of the male and female plants, while in the PGM plants the traits overlap. In general, habitat conditions did not influence either the extent of sexual dimorphism or RA pattern. However, it seems to influence secondary sex-ratio as females show their significant association with soil moisture. Our findings on sexual dimorphism and RA pattern supports attributes of wind-pollination in the species. The observed extent of sexual dimorphism in the species reiterates limited genomic differences among the sexes and the ongoing evolution of dioecy via monoecy in the species. The dynamics of RA in the species appears to be independent of resource availability in the habitats as the species grows in a resource-limited and extreme environment.
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Affiliation(s)
| | - Yash Mangla
- Department of Botany, Kirori Mal College, University of Delhi, New Delhi, Delhi, India
| | - Atika Chandra
- Department of Botany, Maitreyi College, University of Delhi, New Delhi, Delhi, India
| | | | - Rajesh Tandon
- Department of Botany, University of Delhi, New Delhi, India
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Kreiner JM, Hnatovska S, Stinchcombe JR, Wright SI. Quantifying the role of genome size and repeat content in adaptive variation and the architecture of flowering time in Amaranthus tuberculatus. PLoS Genet 2023; 19:e1010865. [PMID: 38150485 PMCID: PMC10775983 DOI: 10.1371/journal.pgen.1010865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/09/2024] [Accepted: 12/11/2023] [Indexed: 12/29/2023] Open
Abstract
Genome size variation, largely driven by repeat content, is poorly understood within and among populations, limiting our understanding of its significance for adaptation. Here we characterize intraspecific variation in genome size and repeat content across 186 individuals of Amaranthus tuberculatus, a ubiquitous native weed that shows flowering time adaptation to climate across its range and in response to agriculture. Sequence-based genome size estimates vary by up to 20% across individuals, consistent with the considerable variability in the abundance of transposable elements, unknown repeats, and rDNAs across individuals. The additive effect of this variation has important phenotypic consequences-individuals with more repeats, and thus larger genomes, show slower flowering times and growth rates. However, compared to newly-characterized gene copy number and polygenic nucleotide changes underlying variation in flowering time, we show that genome size is a marginal contributor. Differences in flowering time are reflected by genome size variation across sexes and marginally, habitats, while polygenic variation and a gene copy number variant within the ATP synthesis pathway show consistently stronger environmental clines than genome size. Repeat content nonetheless shows non-neutral distributions across the genome, and across latitudinal and environmental gradients, demonstrating the numerous governing processes that in turn influence quantitative genetic variation for phenotypes key to plant adaptation.
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Affiliation(s)
- Julia M. Kreiner
- Department of Botany, Biodiversity Research Centre, University of British Columbia
- Department of Ecology & Evolutionary Biology, University of Toronto
| | - Solomiya Hnatovska
- Department of Ecology & Evolutionary Biology, University of Toronto
- Department of Molecular Genetics, University of Toronto
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3
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Tonnabel J, David P, Pannell JR. Rapid divergence in vegetative morphology of a wind-pollinated plant between populations at contrasting densities. Evolution 2022; 76:1737-1748. [PMID: 35713285 PMCID: PMC9544426 DOI: 10.1111/evo.14539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/20/2021] [Accepted: 01/05/2022] [Indexed: 01/22/2023]
Abstract
Plant sexual dimorphism is thought to evolve in response to sex-specific selection associated with competition for access to mates or resources, both of which may be density dependent. In wind-pollinated plants in particular, vegetative traits such as plant size and architecture may influence resource acquisition and both pollen dispersal and receipt, with potential conflict between these two components of fitness. We evaluated the role of plant density in shaping plant traits by measuring evolutionary responses in experimental populations of the sexually dimorphic wind-pollinated plant Mercurialis annua. After three generations of evolution, we observed divergence between high- and low-density populations in several vegetative traits, whereas there was no divergence for reproductive traits. A reversal in the direction of sexually dimorphic traits expressed in young plants evolved in both low- and high-density populations compared to the original population (stored as seeds). Compared to the source population, males at high density evolved to be taller when young, whereas at low density young females tended to become smaller. These results demonstrate that a simple change in plant density can induce age-dependent and sex-specific evolution in the ontogeny of vegetative organs, and illustrates the power of experimental evolution for investigating plant trait evolution.
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Affiliation(s)
- Jeanne Tonnabel
- Department of Ecology and EvolutionUniversity of LausanneLausanneCH‐1015Switzerland,CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, FranceCNRSMontpellier34293France
| | - Patrice David
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, FranceCNRSMontpellier34293France
| | - John R. Pannell
- Department of Ecology and EvolutionUniversity of LausanneLausanneCH‐1015Switzerland
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Beaudry FEG, Rifkin JL, Peake AL, Kim D, Jarvis-Cross M, Barrett SCH, Wright SI. Effects of the neo-X chromosome on genomic signatures of hybridization in Rumex hastatulus. Mol Ecol 2022; 31:3708-3721. [PMID: 35569016 DOI: 10.1111/mec.16496] [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: 02/14/2022] [Revised: 04/23/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022]
Abstract
Natural hybrid zones provide opportunities for studies of the evolution of reproductive isolation in wild populations. Although recent investigations have found that the formation of neo-sex chromosomes is associated with reproductive isolation, the mechanisms remain unclear in most cases. Here, we assess the contemporary structure of gene flow in the contact zone between largely allopatric cytotypes of the dioecious plant Rumex hastatulus, a species with evidence of sex chromosome turn-over. Males to the west of the Mississippi river, USA, have an X and a single Y chromosome, whereas populations to the east of the river have undergone a chromosomal rearrangement giving rise to a larger X and two Y chromosomes. Using reduced-representation sequencing, we provide evidence that hybrids form readily and survive multiple backcross generations in the field, demonstrating the potential for ongoing gene flow between the cytotypes. Cline analysis of each chromosome separately captured no signals of difference in cline shape between chromosomes. However, principal component regression revealed a significant increase in the contribution of individual SNPs to inter-cytotype differentiation on the neo-X chromosome, but no correlation with recombination rate. Cline analysis revealed that the only SNPs with significantly steeper clines than the genome average were located on the neo-X. Our data are consistent with a role for neo-sex chromosomes in reproductive isolation between R. hastatulus cytotypes. Our investigation highlights the importance of studying plant hybrid zones for understanding the evolution of sex chromosomes.
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Affiliation(s)
- Felix E G Beaudry
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Joanna L Rifkin
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Amanda L Peake
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Deanna Kim
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Madeline Jarvis-Cross
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Spencer C H Barrett
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
| | - Stephen I Wright
- The University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, ON, Canada
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Bürli S, Pannell JR, Tonnabel J. Environmental variation in sex ratios and sexual dimorphism in three wind‐pollinated dioecious plant species. OIKOS 2022. [DOI: 10.1111/oik.08651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sarah Bürli
- Dept of Ecology and Evolution, Le Biophore, UNIL‐SORGE, Univ. of Lausanne Lausanne Switzerland
- Botanical Garden&Inst. of Plant Sciences of the Univ. of Bern Bern Switzerland
| | - John R. Pannell
- Dept of Ecology and Evolution, Le Biophore, UNIL‐SORGE, Univ. of Lausanne Lausanne Switzerland
| | - Jeanne Tonnabel
- Dept of Ecology and Evolution, Le Biophore, UNIL‐SORGE, Univ. of Lausanne Lausanne Switzerland
- CEFE, Univ. Montpellier, CNRS, Univ. Paul Valéry Montpellier 3, EPHE, IRD Montpellier France
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Powers JM, Sakai AK, Weller SG, Campbell DR. Variation in floral volatiles across time, sexes, and populations of wind-pollinated Schiedea globosa. AMERICAN JOURNAL OF BOTANY 2022; 109:345-360. [PMID: 35192727 DOI: 10.1002/ajb2.1820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
PREMISE Floral scent is a key aspect of plant reproduction, but its intraspecific variation at multiple scales is poorly understood. Sexual dimorphism and temporal regulation of scent can be shaped by evolution, and interpopulation variation may be a bridge to species differences. We tested whether intraspecific chemical diversity in a wind-pollinated species where selection from biotic pollination is absent is associated with genetic divergence across the Hawaiian archipelago. METHODS Floral volatiles from females, males, and hermaphrodites of subdioecious Schiedea globosa grown in a common environment from 12 populations were sampled day and night and analyzed by gas chromatography-mass spectrometry. Variation among groups was analyzed by constrained ordination. We also examined the relationships of scent dissimilarity to geographic and genetic distance between populations. RESULTS Flowers increased total emissions at night through higher emissions of several ketones, oximes, and phenylacetaldehyde. Females emitted less total scent per flower at night but more of some aliphatic compounds than males, and males emitted more ketones and aldoximes. Scent differed among populations during day and night. Divergence in scent produced at night increased with geographic distance within 70-100 km and increased with genetic distance for males during the day and night, but not for females. CONCLUSIONS Schiedea globosa exhibits diel and sex-based variation in floral scent despite wind pollination and presumed loss of biotic pollination. In males, interpopulation scent differences are correlated with genetic differences, suggesting that scent evolved with dispersal within and across islands.
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Affiliation(s)
- John M Powers
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA
| | - Ann K Sakai
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA
| | - Stephen G Weller
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA
| | - Diane R Campbell
- Department of Ecology and Evolutionary Biology, University of California, Irvine, 321 Steinhaus Hall, Irvine, California, 92697, USA
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Lang AS, Gehrmann T, Cronberg N. Genetic Diversity and Population Structure in Bryophyte With Facultative Nannandry. FRONTIERS IN PLANT SCIENCE 2021; 12:517547. [PMID: 33897717 PMCID: PMC8059434 DOI: 10.3389/fpls.2021.517547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Among plants, gender dimorphism occurs in about 10% of all angiosperms and more than 50% of all moss taxa, with dwarf males (DM) found exclusively in some unisexual mosses. In this study, we explore the role of male dwarfism as a reproductive strategy in the widespread acrocarpous moss Dicranum scoparium, which has facultative male dwarfism, having both dwarf males (DMs) and normal-sized males (NMs). We retrieved 119 SNP markers from transcriptomes which were used to genotype 403 samples from 11 sites at seven localities in southern Sweden. Our aims were to compare the genetic variability and genetic structure of sexually reproducing populations at different geographic levels (cushion, site, and locality) and compare in particular the relative contribution of females, dwarf males and normal-sized males to the observed genetic diversity. The numbers of DMs differed strongly between sites, but when present, they usually outnumbered both females and NMs. Low genetic differentiation was found at locality level. Genetic differentiation was strongest between cushions for females and NMs and within cushions for DMs indicating small scale structuring and sometimes inbreeding. NMs were more clonal than either DMs or females. Genetic diversity was similar between females and DMs, but lower for NMs. Two haplotypes were shared between females and DMs and one haplotype was shared between a DM and a NM. In conclusion, our results show that DMs and NMs play different roles in reproduction, inbreeding may occur at cushion level, but gene flow is high enough to prevent substantial genetic drift.
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Affiliation(s)
| | - Thies Gehrmann
- Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Nils Cronberg
- Department of Biology, Lund University, Lund, Sweden
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Tonnabel J, Klein EK, Ronce O, Oddou-Muratorio S, Rousset F, Olivieri I, Courtiol A, Mignot A. Sex-specific spatial variation in fitness in the highly dimorphic Leucadendron rubrum. Mol Ecol 2021; 30:1721-1735. [PMID: 33559274 DOI: 10.1111/mec.15833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/16/2022]
Abstract
Sexual dimorphism in plants may emerge as a result of sex-specific selection on traits enhancing access to nutritive resources and/or to sexual partners. Here we investigated sex-specific differences in selection of sexually dimorphic traits and in the spatial distribution of effective fecundity (our fitness proxy) in a highly dimorphic dioecious wind-pollinated shrub, Leucadendron rubrum. In particular, we tested for the effect of density on male and female effective fecundity. We used spatial and genotypic data of parent and offspring cohorts to jointly estimate individual male and female effective fecundity on the one hand and pollen and seed dispersal kernels on the other hand. This methodology was adapted to the case of dioecious species. Explicitly modelling dispersal avoids the confounding effects of heterogeneous spatial distribution of mates and sampled seedlings on the estimation of effective fecundity. We also estimated selection gradients on plant traits while modelling sex-specific spatial autocorrelation in fecundity. Males exhibited spatial autocorrelation in effective fecundity at a smaller scale than females. A higher local density of plants was associated with lower effective fecundity in males but was not related to female effective fecundity. These results suggest sex-specific sensitivities to environmental heterogeneity in L. rubrum. Despite these sexual differences, we found directional selection for wider canopies and smaller leaves in both sexes, and no sexually antagonistic selection on strongly dimorphic traits in L. rubrum. Many empirical studies in animals similarly failed to detect sexually antagonistic selection in species expressing strong sexual dimorphism, and we discuss reasons explaining this common pattern.
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Affiliation(s)
- Jeanne Tonnabel
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Department of Ecology and Evolution, Le Biophore, UNIL-SORGE, University of Lausanne, Lausanne, Switzerland
| | | | - Ophélie Ronce
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.,CNRS, Biodiversity Research Center, University of British Columbia, Vancouver, Canada
| | | | - François Rousset
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Isabelle Olivieri
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Alexandre Courtiol
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Agnès Mignot
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
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Beaudry FEG, Barrett SCH, Wright SI. Ancestral and neo-sex chromosomes contribute to population divergence in a dioecious plant. Evolution 2019; 74:256-269. [PMID: 31808547 DOI: 10.1111/evo.13892] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 10/16/2019] [Accepted: 11/11/2019] [Indexed: 12/18/2022]
Abstract
Empirical evidence from several animal groups suggests sex chromosomes disproportionately contribute to reproductive isolation. This effect may be enhanced when sex chromosomes are associated with turnover of sex determination systems resulting from structural rearrangements to the chromosomes. We investigated these predictions in the dioecious plant Rumex hastatulus, which is composed of populations of two different sex chromosome cytotypes caused by an X-autosome fusion. Using population genomic analyses, we investigated the demographic history of R. hastatulus and explored the contributions of ancestral and neo-sex chromosomes to population genetic divergence. Our study revealed that the cytotypes represent genetically divergent populations with evidence for historical but not contemporary gene flow between them. In agreement with classical predictions, we found that the ancestral X chromosome was disproportionately divergent compared with the rest of the genome. Excess differentiation was also observed on the Y chromosome, even when we used measures of differentiation that control for differences in effective population size. Our estimates of the timing of the origin of neo-sex chromosomes in R. hastatulus are coincident with cessation of gene flow, suggesting that the chromosomal fusion event that gave rise to the origin of the XYY cytotype may have also contributed to reproductive isolation.
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Affiliation(s)
- Felix E G Beaudry
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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Schoen DJ, Johnson MTJ, Wright SI. The ecology, evolution, and genetics of plant reproductive systems. THE NEW PHYTOLOGIST 2019; 224:999-1004. [PMID: 31631365 DOI: 10.1111/nph.16222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Daniel J Schoen
- Department of Biology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - Marc T J Johnson
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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