1
|
Zhou Y, Pang Z, Yuan Z, Fallah N, Jia H, Ming R. Sex-based metabolic and microbiota differences in roots and rhizosphere soils of dioecious papaya ( Carica papaya L.). FRONTIERS IN PLANT SCIENCE 2022; 13:991114. [PMID: 36311075 PMCID: PMC9612958 DOI: 10.3389/fpls.2022.991114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Dioecious plant species have a high genetic variation that is important for coping with or adapting to environmental stress through natural selection. Intensive studies have reported dimorphism morphism in morphology, physiology, as well as biotic and abiotic stress responses in dioecious plants. Here, we demonstrated the dimorphism of metabolic profile and the preference of some microorganisms in the roots and rhizosphere soils of male and female papaya. The metabolic composition of roots were significantly different between the males and females. Some sex hormones occurred in the differential metabolites in roots and rhizosphere soils. For example, testosterone was up-regulated in male papaya roots and rhizosphere soils, whereas norgestrel was up-regulated in the female papaya roots, indicating a possible balance in papaya roots to control the sexual differentiation. Plant hormones such as BRs, JAs, SA and GAs were also detected among the differential metabolites in the roots and rhizosphere soils of dioecious papaya. In addition, some metabolites that have medicinal values, such as ecliptasaponin A, crocin, berberine and sapindoside A were also expressed differentially between the two sexes. Numerous differential metabolites from the papaya roots were secreted in the soil, resulting in the differences in microbial community structure in the roots and rhizosphere soils. Some nitrogen-fixing bacteria such as Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Brevundimonas and Microvirga were enriched in the male papaya roots or rhizosphere soils. While Candidatus Solibacter and Tumebacillus, which utilize organic matters, were enriched in the roots or rhizosphere soils of the female papaya. Some differences in the fungi abundance were also observed in both male and female papaya roots. These findings uncovered the effect of sex types on the metabolic and microbiota differences in roots and rhizosphere soils in papaya and will lead to investigations of underlining genomic and molecular mechanisms.
Collapse
Affiliation(s)
- Yongmei Zhou
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ziqin Pang
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhaonian Yuan
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Nyumah Fallah
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Haifeng Jia
- FAFU and UIUC Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ray Ming
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| |
Collapse
|
2
|
Kazama Y, Kitoh M, Kobayashi T, Ishii K, Krasovec M, Yasui Y, Abe T, Kawano S, Filatov DA. A CLAVATA3-like Gene Acts as a Gynoecium Suppression Function in White Campion. Mol Biol Evol 2022; 39:msac195. [PMID: 36166820 PMCID: PMC9550985 DOI: 10.1093/molbev/msac195] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
How do separate sexes originate and evolve? Plants provide many opportunities to address this question as they have diverse mating systems and separate sexes (dioecy) that evolved many times independently. The classic "two-factor" model for evolution of separate sexes proposes that males and females can evolve from hermaphrodites via the spread of male and female sterility mutations that turn hermaphrodites into females and males, respectively. This widely accepted model was inspired by early genetic work in dioecious white campion (Silene latifolia) that revealed the presence of two sex-determining factors on the Y-chromosome, though the actual genes remained unknown. Here, we report identification and functional analysis of the putative sex-determining gene in S. latifolia, corresponding to the gynoecium suppression factor (GSF). We demonstrate that GSF likely corresponds to a Y-linked CLV3-like gene that is specifically expressed in early male flower buds and encodes the protein that suppresses gynoecium development in S. latifolia. Interestingly, GSFY has a dysfunctional X-linked homolog (GSFX) and their synonymous divergence (dS = 17.9%) is consistent with the age of sex chromosomes in this species. We propose that female development in S. latifolia is controlled via the WUSCHEL-CLAVATA feedback loop, with the X-linked WUSCHEL-like and Y-linked CLV3-like genes, respectively. Evolution of dioecy in the S. latifolia ancestor likely involved inclusion of ancestral GSFY into the nonrecombining region on the nascent Y-chromosome and GSFX loss of function, which resulted in disbalance of the WUSCHEL-CLAVATA feedback loop between the sexes and ensured gynoecium suppression in males.
Collapse
Affiliation(s)
- Yusuke Kazama
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Moe Kitoh
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
| | - Taiki Kobayashi
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
| | - Kotaro Ishii
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Marc Krasovec
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
- Sorbonne Université, CNRS, UMR 7232 Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France
| | - Yasuo Yasui
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tomoko Abe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shigeyuki Kawano
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, FSB-601, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
- Future Center Initiative, The University of Tokyo, 178-4-4 Wakashiba, Kashiwa, Chiba 277-0871, Japan
| | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| |
Collapse
|
3
|
Yakimowski SB, Southcott L, Barrett SCH. Contrasting patterns of genetic diversity and differentiation across the continental disjunct range of a sexually polymorphic aquatic plant. ANNALS OF BOTANY 2022; 130:27-40. [PMID: 35511701 PMCID: PMC9295920 DOI: 10.1093/aob/mcac056] [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: 12/08/2021] [Accepted: 04/28/2022] [Indexed: 05/05/2023]
Abstract
BACKGROUND AND AIMS Reproductive systems enabling opportunities for self-fertilization influence population genetic structure and play a key role in colonization and genetic differentiation during range expansion. Because of their well-developed powers of dispersal, aquatic plants often have widespread disjunct geographical distributions, providing opportunities to investigate the role of reproductive systems in structuring genetic variation between parts of the range that differ in migration history and ecology. METHODS We compared reproductive systems and spatial genetic structure of the freshwater aquatic macrophyte Sagittaria latifolia between disjunct western and eastern ranges of North America (NA). Populations of this species are most commonly either monoecious or dioecious. We examined chloroplast DNA haplotype variation to test the hypothesis that the western range of this species represents a secondary colonization from the east, and evaluated the roles of reproductive system differences and geography in structuring contemporary patterns of genetic variation at 11 polymorphic SSR (simple sequence repeat) loci. KEY RESULTS Chloroplast haplotyping revealed a single haplotype in western NA compared to numerous haplotypes in eastern NA, consistent with a genetic bottleneck during westward migration. Estimates of genetic diversity in eastern NA populations differed significantly between reproductive systems, but this pattern was not evident in the western range. Eastern populations could be reliably assigned to genetic clusters based on their reproductive systems, whereas western populations clustered primarily by geographical location. CONCLUSIONS The sparser distribution of aquatic habitats in the drier western range of S. latifolia, combined with secondary colonization of this region, probably cause the lower genetic diversity and increased differentiation among populations, possibly overriding the effects of reproductive system evident in the eastern portion of the range. Our findings demonstrate that the complex interplay between migratory history, reproductive systems and habitat availability plays an important role in structuring spatial patterns of genetic variation in disjunct plant populations.
Collapse
Affiliation(s)
| | - Laura Southcott
- Department of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, ON, Canada
- Committee on Evolutionary Biology, Chicago, IL, USA
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
4
|
Gong W, Filatov DA. Evolution of the sex-determining region in Ginkgo biloba. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210229. [PMID: 35306884 PMCID: PMC8935300 DOI: 10.1098/rstb.2021.0229] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sex chromosomes or sex-determining regions (SDR) have been discovered in many dioecious plant species, including the iconic ‘living fossil' Ginkgo biloba, though the location and size of the SDR in G. biloba remain contradictory. Here we resolve these controversies and analyse the evolution of the SDR in this species. Based on transcriptome sequencing data from four genetic crosses we reconstruct male- and female-specific genetic maps and locate the SDR to the middle of chromosome 2. Integration of the genetic maps with the genome sequence reveals that recombination in and around the SDR is suppressed in a region of about 50 Mb in both males and females. However, occasional recombination does occur except a small, less than 5 Mb long region that does not recombine in males. Based on synonymous divergence between homologous X- and Y-linked genes in this region, we infer that the Ginkgo SDR is fairly old—at least of Cretaceous origin. The analysis of substitution rates and gene expression reveals only slight Y-degeneration. These results are consistent with findings in other dioecious plants with homomorphic sex chromosomes, where the SDR is typically small and evolves in a region with pre-existing reduced recombination, surrounded by long actively recombining pseudoautosomal regions. This article is part of the theme issue ‘Sex determination and sex chromosome evolution in land plants’.
Collapse
Affiliation(s)
- Wei Gong
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, People's Republic of China.,Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK
| | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK
| |
Collapse
|
5
|
Abstract
In flowering plants, transitions from bisexuality to unisexuality occur often, and have been considered irreversible. A new experimental evolution study demonstrates that this is unlikely to be true - 'leaky' sex expression can promote reversions to hermaphroditism when mates are scarce.
Collapse
Affiliation(s)
- Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willocks Street, Toronto, ON, Canada.
| |
Collapse
|
6
|
Li C, Wang X, Xiao Y, Sun X, Wang J, Yang X, Sun Y, Sha Y, Lv R, Yu Y, Ding B, Zhang Z, Li N, Wang T, Wendel JF, Liu B, Gong L. Coevolution in Hybrid Genomes: Nuclear-Encoded Rubisco Small Subunits and Their Plastid-Targeting Translocons Accompanying Sequential Allopolyploidy Events in Triticum. Mol Biol Evol 2020; 37:3409-3422. [PMID: 32602899 PMCID: PMC7743682 DOI: 10.1093/molbev/msaa158] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Triticum/Aegilops complex includes hybrid species resulting from homoploid hybrid speciation and allopolyploid speciation. Sequential allotetra- and allohexaploidy events presumably result in two challenges for the hybrids, which involve 1) cytonuclear stoichiometric disruptions caused by combining two diverged nuclear genomes with the maternal inheritance of the cytoplasmic organellar donor; and 2) incompatibility of chimeric protein complexes with diverged subunits from nuclear and cytoplasmic genomes. Here, we describe coevolution of nuclear rbcS genes encoding the small subunits of Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase) and nuclear genes encoding plastid translocons, which mediate recognition and translocation of nuclear-encoded proteins into plastids, in allopolyploid wheat species. We demonstrate that intergenomic paternal-to-maternal gene conversion specifically occurred in the genic region of the homoeologous rbcS3 gene from the D-genome progenitor of wheat (abbreviated as rbcS3D) such that it encodes a maternal-like or B-subgenome-like SSU3D transit peptide in allohexaploid wheat but not in allotetraploid wheat. Divergent and limited interaction between SSU3D and the D-subgenomic TOC90D translocon subunit is implicated to underpin SSU3D targeting into the chloroplast of hexaploid wheat. This implicates early selection favoring individuals harboring optimal maternal-like organellar SSU3D targeting in hexaploid wheat. These data represent a novel dimension of cytonuclear evolution mediated by organellar targeting and transportation of nuclear proteins.
Collapse
Affiliation(s)
- Changping Li
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Xiaofei Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Yaxian Xiao
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Xuhan Sun
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Jinbin Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Xuan Yang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Yuchen Sun
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Yan Sha
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Ruili Lv
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Yanan Yu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Baoxu Ding
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Zhibin Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Ning Li
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Tianya Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Jonathan F Wendel
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Lei Gong
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| |
Collapse
|
7
|
Pickup M, Brandvain Y, Fraïsse C, Yakimowski S, Barton NH, Dixit T, Lexer C, Cereghetti E, Field DL. Mating system variation in hybrid zones: facilitation, barriers and asymmetries to gene flow. THE NEW PHYTOLOGIST 2019; 224:1035-1047. [PMID: 31505037 PMCID: PMC6856794 DOI: 10.1111/nph.16180] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/19/2019] [Indexed: 05/11/2023]
Abstract
Plant mating systems play a key role in structuring genetic variation both within and between species. In hybrid zones, the outcomes and dynamics of hybridization are usually interpreted as the balance between gene flow and selection against hybrids. Yet, mating systems can introduce selective forces that alter these expectations; with diverse outcomes for the level and direction of gene flow depending on variation in outcrossing and whether the mating systems of the species pair are the same or divergent. We present a survey of hybridization in 133 species pairs from 41 plant families and examine how patterns of hybridization vary with mating system. We examine if hybrid zone mode, level of gene flow, asymmetries in gene flow and the frequency of reproductive isolating barriers vary in relation to mating system/s of the species pair. We combine these results with a simulation model and examples from the literature to address two general themes: (1) the two-way interaction between introgression and the evolution of reproductive systems, and (2) how mating system can facilitate or restrict interspecific gene flow. We conclude that examining mating system with hybridization provides unique opportunities to understand divergence and the processes underlying reproductive isolation.
Collapse
Affiliation(s)
- Melinda Pickup
- Institute of Science and Technology AustriaAm Campus 1Klosterneuburg3400Austria
| | - Yaniv Brandvain
- Department of Plant and Microbial BiologyUniversity of Minnesota1500 Gortner AveSt Paul, MinneapolisMN55108USA
| | - Christelle Fraïsse
- Institute of Science and Technology AustriaAm Campus 1Klosterneuburg3400Austria
| | - Sarah Yakimowski
- Department of BiologyQueen's University116 Barrie StKingstonONK7L 3N6Canada
| | - Nicholas H. Barton
- Institute of Science and Technology AustriaAm Campus 1Klosterneuburg3400Austria
| | - Tanmay Dixit
- Department of ZoologyUniversity of CambridgeDowning StreetCambridgeCB2 3EJUK
| | - Christian Lexer
- Department of Botany and Biodiversity ResearchFaculty of Life SciencesUniversity of ViennaA‐1030ViennaAustria
| | - Eva Cereghetti
- Institute of Science and Technology AustriaAm Campus 1Klosterneuburg3400Austria
| | - David L. Field
- Department of Botany and Biodiversity ResearchFaculty of Life SciencesUniversity of ViennaA‐1030ViennaAustria
- School of ScienceEdith Cowan University270 Joondalup DriveJoondalupWestern Australia6027Australia
| |
Collapse
|
8
|
Wang LL, Zhang ZQ, Yang YP, Duan YW. The coexistence of hermaphroditic and dioecious plants is associated with polyploidy and gender dimorphism in Dasiphora fruticosa. PLANT DIVERSITY 2019; 41:323-329. [PMID: 31934677 PMCID: PMC6951273 DOI: 10.1016/j.pld.2019.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Dasiphora fruticosa comprises male, female and hermaphrodite plants, which are distributed sympatrically in some populations on the Qinghai-Tibet Plateau. To explore what governs the coexistence of these three sexual phenotypes, we investigated the DNA contents, pollen and ovule production, pollen deposition, and performed hand-pollination in both hermaphroditic and dioecious individuals of D. fruticosa. Flow cytometry confirmed that the DNA content of males and females were almost twice as much as that of the hermaphrodites. Male and female flowers produced more pollen grains and ovules than hermaphroditic flowers. Hand-pollinated treatments showed that unisexual flowers were sterile in one sexual function and bisexual flowers were fertile for both functions, but no sterile seeds were produced between unisexual and bisexual flowers. Our findings imply that polyploidy is related to gender dimorphism, and both are likely to play a strong role in the coexistence of two cryptic biological species of D. fruticosa (low ploidy hermaphroditic species and high ploidy dioecious species) in the Qinghai-Tibet Plateau.
Collapse
Affiliation(s)
- Lin-Lin Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhi-Qiang Zhang
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, Yunnan, 650091, China
| | - Yong-Ping Yang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
| | - Yuan-Wen Duan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Germplasm Bank of Wild Species, Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
| |
Collapse
|
9
|
Rivkin LR, Barrett SCH, Johnson MTJ. The effects of plant sexual system and latitude on resistance to herbivores. AMERICAN JOURNAL OF BOTANY 2018; 105:977-985. [PMID: 29917233 DOI: 10.1002/ajb2.1098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY The strength of plant-herbivore interactions varies in space and time, but the factors that explain this variation are poorly understood. Several lines of research suggest that variation in plant reproductive systems and latitude may explain resistance against herbivores, but how these factors jointly affect plant-herbivore interactions has not been investigated in detail. We examined the effects of latitude, sexual system, and plant gender on herbivory in Sagittaria latifolia, an aquatic plant in which populations are typically monoecious (separate female and male flowers) or dioecious (separate female and male plants). METHODS We surveyed 43 populations of S. latifolia between 42 and 48° N in Ontario, Canada. In each population, we recorded the sexual system and obtained estimates of herbivore damage to ramets of known gender (i.e. female, male, or hermaphrodite) by the weevil Listronotus appendiculatus, the principal herbivore of S. latifolia. Herbivore damage was quantified as the percent leaf area removed by adult L. appendiculatus weevils, and the abundance of larvae feeding within flowering stalks, which was correlated with the amount of damage by herbivores to the inflorescence. KEY RESULTS Leaf herbivory significantly decreased with increasing latitude but did not vary with sexual system or plant gender. By contrast, larvae were more abundant in dioecious populations and on female plants, corresponding to increased stem damage, providing evidence for sex-biased larval abundance in S. latifolia. These effects of sexual system and gender on larval abundance were strongest at lower latitudes. CONCLUSIONS Our study found latitudinal variation in leaf herbivory and sex-biased resistance to weevil larvae that feed on the reproductive tissues of S. latifolia, which is predicted to be a necessary condition for herbivory to influence the evolution of dioecy.
Collapse
Affiliation(s)
- L R Rivkin
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Biology, University of Toronto Mississauga, Ontario, L5L 1C6, Canada
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - Marc T J Johnson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Biology, University of Toronto Mississauga, Ontario, L5L 1C6, Canada
| |
Collapse
|
10
|
Käfer J, Marais GAB, Pannell JR. On the rarity of dioecy in flowering plants. Mol Ecol 2017; 26:1225-1241. [PMID: 28101895 DOI: 10.1111/mec.14020] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 12/27/2016] [Accepted: 12/28/2016] [Indexed: 01/21/2023]
Abstract
Dioecy, the coexistence of separate male and female individuals in a population, is a rare but phylogenetically widespread sexual system in flowering plants. While research has concentrated on why and how dioecy evolves from hermaphroditism, the question of why dioecy is rare, despite repeated transitions to it, has received much less attention. Previous phylogenetic and theoretical studies have suggested that dioecy might be an evolutionary dead end. However, recent research indicates that the phylogenetic support for this hypothesis is attributable to a methodological bias and that there is no evidence for reduced diversification in dioecious angiosperms. The relative rarity of dioecy thus remains a puzzle. Here, we review evidence for the hypothesis that dioecy might be rare not because it is an evolutionary dead end, but rather because it easily reverts to hermaphroditism. We review what is known about transitions between hermaphroditism and dioecy, and conclude that there is an important need to consider more widely the possibility of transitions away from dioecy, both from an empirical and a theoretical point of view, and by combining tools from molecular evolution and insights from ecology.
Collapse
Affiliation(s)
- Jos Käfer
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, Bât. Grégor Mendel 43, bd du 11 novembre 1918, 69622, Villeurbanne cedex, France
| | - Gabriel A B Marais
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, Bât. Grégor Mendel 43, bd du 11 novembre 1918, 69622, Villeurbanne cedex, France
| | - John R Pannell
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
| |
Collapse
|