1
|
Henshaw JM, Bittlingmaier M, Schärer L. Hermaphroditic origins of anisogamy. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220283. [PMID: 36934747 PMCID: PMC10024982 DOI: 10.1098/rstb.2022.0283] [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: 09/01/2022] [Accepted: 11/23/2022] [Indexed: 03/21/2023] Open
Abstract
Anisogamy-the size dimorphism of gametes-is the defining difference between the male and female sexual strategies. Game-theoretic thinking led to the first convincing explanation for the evolutionary origins of anisogamy in the 1970s. Since then, formal game-theoretic models have continued to refine our understanding of when and why anisogamy should evolve. Such models typically presume that the earliest anisogamous organisms had separate sexes. However, in most taxa, there is no empirical evidence to support this assumption. Here, we present a model of the coevolution of gamete size and sex allocation, which allows for anisogamy to emerge alongside either hermaphroditism or separate sexes. We show that hermaphroditic anisogamy can evolve directly from isogamous ancestors when the average size of spawning groups is small and fertilization is relatively efficient. Sex allocation under hermaphroditism becomes increasingly female-biased as group size decreases and the degree of anisogamy increases. When spawning groups are very small, our model also predicts the existence of complex isogamous organisms in which individuals allocate resources equally to two large gamete types. We discuss common, but potentially unwarranted, assumptions in the literature that could be relaxed in future models. This article is part of the theme issue 'Half a century of evolutionary games: a synthesis of theory, application and future directions'.
Collapse
Affiliation(s)
- Jonathan M. Henshaw
- Institute of Biology I, University of Freiburg, Hauptstraße 1, D-79104 Freiburg, Germany
| | - Markus Bittlingmaier
- Institute of Biology I, University of Freiburg, Hauptstraße 1, D-79104 Freiburg, Germany
- Theoretical and Experimental Ecology Station, CNRS, 2 route du CNRS, 09200 Moulis, France
| | - Lukas Schärer
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel CH-4051, Switzerland
| |
Collapse
|
2
|
Fujiwara T, Liu H, Meza-Torres EI, Morero RE, Vega AJ, Liang Z, Ebihara A, Leitch IJ, Schneider H. Evolution of genome space occupation in ferns: linking genome diversity and species richness. ANNALS OF BOTANY 2023; 131:59-70. [PMID: 34259813 PMCID: PMC9904345 DOI: 10.1093/aob/mcab094] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/10/2021] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS The dynamics of genome evolution caused by whole genome duplications and other processes are hypothesized to shape the diversification of plants and thus contribute to the astonishing variation in species richness among the main lineages of land plants. Ferns, the second most species-rich lineage of land plants, are highly suitable to test this hypothesis because of several unique features that distinguish fern genomes from those of seed plants. In this study, we tested the hypothesis that genome diversity and disparity shape fern species diversity by recording several parameters related to genome size and chromosome number. METHODS We conducted de novo measurement of DNA C-values across the fern phylogeny to reconstruct the phylogenetic history of the genome space occupation in ferns by integrating genomic parameters such as genome size, chromosome number and average DNA amount per chromosome into a time-scaled phylogenetic framework. Using phylogenetic generalized least square methods, we determined correlations between chromosome number and genome size, species diversity and evolutionary rates of their transformation. KEY RESULTS The measurements of DNA C-values for 233 species more than doubled the taxon coverage from ~2.2 % in previous studies to 5.3 % of extant diversity. The dataset not only documented substantial differences in the accumulation of genomic diversity and disparity among the major lineages of ferns but also supported the predicted correlation between species diversity and the dynamics of genome evolution. CONCLUSIONS Our results demonstrated substantial genome disparity among different groups of ferns and supported the prediction that alterations of reproductive modes alter trends of genome evolution. Finally, we recovered evidence for a close link between the dynamics of genome evolution and species diversity in ferns for the first time.
Collapse
Affiliation(s)
- Tao Fujiwara
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan, China
- Makino Herbarium, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, Japan
| | - Hongmei Liu
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan, China
| | - Esteban I Meza-Torres
- Instituto de Botánica del Nordeste, Universidad Nacional del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas, Corrientes, Argentina
| | - Rita E Morero
- Instituto Multidiscipinario de Biologia Vegetal, Universidad Nacional de Cordoba, Consejo Nacional de Investigaciones Científicas y Tecnicas, Cordoba, Argentina
| | - Alvaro J Vega
- Instituto de Botánica del Nordeste, Universidad Nacional del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas, Corrientes, Argentina
| | - Zhenlong Liang
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan, China
| | - Atsushi Ebihara
- Department of Botany, National Museum of Nature and Sciences, Tsukuba, Japan
| | | | | |
Collapse
|
3
|
Bonacorsi NK, Gensel PG, Hueber FM, Wellman CH, Leslie AB. A novel reproductive strategy in an Early Devonian plant. Curr Biol 2021; 30:R388-R389. [PMID: 32369746 DOI: 10.1016/j.cub.2020.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Bonacorsi et al. describe a new fossil from the Early Devonian that provides the earliest clear evidence for more advanced reproductive biology in land plants. The plant produced multiple spore size classes, which is an essential innovation necessary for all advanced plant reproductive strategies, including seeds and flowers.
Collapse
Affiliation(s)
- Nikole K Bonacorsi
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Patricia G Gensel
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | - Charles H Wellman
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew B Leslie
- Geological Sciences Department, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
4
|
Abstract
The gametophyte represents the sexual phase in the alternation of generations in plants; the other, nonsexual phase is the sporophyte. Here, we review the evolutionary origins of the male gametophyte among land plants and, in particular, its ontogenesis in flowering plants. The highly reduced male gametophyte of angiosperm plants is a two- or three-celled pollen grain. Its task is the production of two male gametes and their transport to the female gametophyte, the embryo sac, where double fertilization takes place. We describe two phases of pollen ontogenesis-a developmental phase leading to the differentiation of the male germline and the formation of a mature pollen grain and a functional phase representing the pollen tube growth, beginning with the landing of the pollen grain on the stigma and ending with double fertilization. We highlight recent advances in the complex regulatory mechanisms involved, including posttranscriptional regulation and transcript storage, intracellular metabolic signaling, pollen cell wall structure and synthesis, protein secretion, and phased cell-cell communication within the reproductive tissues.
Collapse
Affiliation(s)
- Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
| |
Collapse
|
5
|
Hornych O, Testo WL, Sessa EB, Watkins JE, Campany CE, Pittermann J, Ekrt L. Insights into the evolutionary history and widespread occurrence of antheridiogen systems in ferns. THE NEW PHYTOLOGIST 2021; 229:607-619. [PMID: 32740926 PMCID: PMC7754499 DOI: 10.1111/nph.16836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/21/2020] [Indexed: 05/23/2023]
Abstract
Sex expression of homosporous ferns is controlled by multiple factors, one being the antheridiogen system. Antheridiogens are pheromones released by sexually mature female fern gametophytes, turning nearby asexual gametophytes precociously male. Nevertheless, not all species respond. It is still unknown how many fern species use antheridiogens, how the antheridiogen system evolved, and whether it is affected by polyploidy and/or apomixis. We tested the response of 68 fern species to antheridiogens in cultivation. These results were combined with a comprehensive review of literature to form the largest dataset of antheridiogen interactions to date. Analyzed species also were coded as apomictic or sexual and diploid or polyploid. Our final dataset contains a total of 498 interactions involving 208 species (c. 2% of all ferns). About 65% of studied species respond to antheridiogen. Multiple antheridiogen types were delimited and their evolution is discussed. Antheridiogen responsiveness was not significantly affected by apomixis or polyploidy. Antheridiogens are widely used by ferns to direct sex expression. The antheridiogen system likely evolved multiple times and provides homosporous ferns with the benefits often associated with heterospory, such as increased rates of outcrossing. Despite expectations, antheridiogens may be beneficial to polyploids and apomicts.
Collapse
Affiliation(s)
- Ondřej Hornych
- Department of BotanyFaculty of ScienceUniversity of South BohemiaBranišovská 1760České BudějoviceCZ37005Czech Republic
| | - Weston L. Testo
- Department of BiologyUniversity of FloridaBox 118525GainesvilleFL32611USA
| | - Emily B. Sessa
- Department of BiologyUniversity of FloridaBox 118525GainesvilleFL32611USA
| | - James E. Watkins
- Department of BiologyColgate University13 Oak Drive HamiltonHamiltonNY13346USA
| | | | - Jarmila Pittermann
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCA95060USA
| | - Libor Ekrt
- Department of BotanyFaculty of ScienceUniversity of South BohemiaBranišovská 1760České BudějoviceCZ37005Czech Republic
| |
Collapse
|
6
|
Lehtonen J, Dardare L. Mathematical Models of Fertilization—An Eco-Evolutionary Perspective. THE QUARTERLY REVIEW OF BIOLOGY 2019. [DOI: 10.1086/703633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
7
|
Abstract
With the origin of pollination in ancient seed plants, the male gametophyte ("pollen") began to evolve a new and unique life history stage, the progamic phase, a post-pollination period in which pollen sexual maturation occurs in interaction with sporophyte-derived tissues. Pollen performance traits mediate the timing of the fertilization process, often in competition with other pollen, via the speed of pollen germination, sperm development, and pollen tube growth. Studies of pollen development rarely address the issue of performance or its evolution, which involves linking variation in developmental rates to relative fitness within populations or to adaptations on a macroevolutionary scale. Modifications to the pollen tube pathway and changes in the intensity of pollen competition affect the direction and strength of selection on pollen performance. Hence, pollen developmental evolution is always contextual-it involves both the population biology of pollen reaching stigmas and the co-evolution of sporophytic traits, such as the pollen tube pathway and mating system. For most species, performance evolution generally reflects a wandering history of periods of directional selection and relaxed selection, channeled by developmental limitations, a pattern that favors the accumulation of diversity and redundancy in developmental mechanisms and the genetic machinery. Developmental biologists are focused on finding universal mechanisms that underlie pollen function, and these are largely mechanisms that have evolved through their effects on performance. Here, we suggest ways in which studies of pollen performance or function could progress by cross-fertilization between the "evo" and "devo" fields.
Collapse
Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
| | - John B Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States
| |
Collapse
|
8
|
Abstract
The reproductive adaptations of land plants have played a key role in their terrestrial colonization and radiation. This encompasses mechanisms used for the production, dispersal and union of gametes to support sexual reproduction. The production of small motile male gametes and larger immotile female gametes (oogamy) in specialized multicellular gametangia evolved in the charophyte algae, the closest extant relatives of land plants. Reliance on water and motile male gametes for sexual reproduction was retained by bryophytes and basal vascular plants, but was overcome in seed plants by the dispersal of pollen and the guided delivery of non-motile sperm to the female gametes. Here we discuss the evolutionary history of male gametogenesis in streptophytes (green plants) and the underlying developmental biology, including recent advances in bryophyte and angiosperm models. We conclude with a perspective on research trends that promise to deliver a deeper understanding of the evolutionary and developmental mechanisms of male gametogenesis in plants.
Collapse
Affiliation(s)
- Dieter Hackenberg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
| |
Collapse
|
9
|
Petersen KB, Burd M. The adaptive value of heterospory: Evidence from Selaginella. Evolution 2018; 72:1080-1091. [PMID: 29645092 DOI: 10.1111/evo.13484] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 03/19/2018] [Indexed: 12/26/2022]
Abstract
Heterospory was a pivotal evolutionary innovation for land plants, but it has never been clear why it evolved. We used the geographic distributions of 114 species of the heterosporous lycophyte Selaginella to explore the functional ecology of microspore and megaspore size, traits that would be correlated with many aspects of a species' regeneration niche. We characterized habitats at a global scale using leaf area index (LAI), a measure of foliage density and thus shading, and net primary productivity (NPP), a measure of growth potential. Microspore size tends to decrease as habitat LAI and NPP increase, a trend that could be related to desiccation resistance or to filtration of wind-borne particles by leaf surfaces. Megaspore size tends to increase among species that inhabit regions of high LAI, but there is an important interaction with NPP. This geographical pattern suggests that larger megaspores provide an establishment advantage in shaded habitats, although in open habitats, where light is less limiting, higher productivity of the environment seems to give an advantage to species with smaller megaspores. These results support previous theoretical arguments that heterospory was originally an adaptation to the increasing height and density of Devonian vegetative canopies that accompanied the diversification of vascular plants with leaves.
Collapse
Affiliation(s)
- Kurt B Petersen
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| |
Collapse
|
10
|
Petersen KB, Burd M. The enigma of sex allocation in Selaginella. ANNALS OF BOTANY 2018; 121:377-383. [PMID: 29300810 PMCID: PMC5808784 DOI: 10.1093/aob/mcx163] [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: 08/09/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND AIMS The division of resource investment between male and female functions is poorly known for land plants other than angiosperms. The ancient lycophyte genus Selaginella is similar in some ways to angiosperms (in heterospory and in having sex allocation occur in the sporophyte generation, for example) but lacks the post-fertilization maternal investments that angiosperms make via fruit and seed tissues. One would therefore expect Selaginella to have sex allocation values less female-biased than in flowering plants and closer to the theoretical prediction of equal investment in male and female functions. Nothing is currently known of sex allocation in the genus, so even the simplest predictions have not been tested. METHODS Volumetric measurements of microsporangial and megasporangial investment were made in 14 species of Selaginella from four continents. In five of these species the length of the main above-ground axis of each plant was measured to determine whether sex allocation is related to plant size. KEY RESULTS Of the 14 species, 13 showed male-biased allocations, often extreme, in population means and among the great majority of individual plants. There was some indication from the five species with axis length measurements that relative male allocation might be related to the release height of spores, but this evidence is preliminary. CONCLUSIONS Sex allocation in Selaginella provides a phylogenetic touchstone showing how the innovations of fruit and seed investment in the angiosperm life cycle lead to typically female-biased allocations in that lineage. Moreover, the male bias we found in Selaginella requires an evolutionary explanation. The bias was often greater than what would occur from the mere absence of seed and fruit investments, and thus poses a challenge to sex allocation theory. It is possible that differences between microspores and megaspores in their dispersal ecology create selective effects that favour male-biased sexual allocation. This hypothesis remains tentative.
Collapse
Affiliation(s)
- Kurt B Petersen
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| |
Collapse
|