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Kumar M, Sirohi U, Yadav MK, Chaudhary V. In Vitro Culture Technology and Advanced Biotechnology Tools Toward Improvement in Gladiolus (Gladiolus species): Present Scenario and Future Prospects. Mol Biotechnol 2024; 66:1806-1835. [PMID: 37528332 DOI: 10.1007/s12033-023-00818-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 07/07/2023] [Indexed: 08/03/2023]
Abstract
In the world's flower trade, gladiolus (Gladiolus spp.) is ranked first among bulbous flowers and eighth among cut flowers, with more than 30,000 different cultivars being grown. Mass multiplication and commercialization are restricted by the traditional propagation methods. However, the large-scale proliferation and improvement of the gladiolus have been accomplished with the aid of plant tissue culture and other biotechnological techniques. The current review includes a thorough examination of the growth and development parameters required for successful in vitro gladiolus development as well as cormel formation. Moreover, focus is being given to various techniques and methods such as in vitro cytogenetic stability and modification of chromosome number, in vitro mutagenesis and selection of pest resistance, in vitro identification and selection to develop virus-free germplasm, cryopreservation, synthetic seed technology, identifying virus diseases by RT-PCR, somaclonal variation, and protoplast and somatic hybridization. Molecular markers and their applications for genetic diversity analysis, relationships between different genotypes, and clonal stability analysis in Gladiolus species have been conducted by several research groups worldwide and are also being discussed. The article also covers efforts to enhance the functionality of plant phenotypes through genetic transformation. Future prospects for further improvement of ornamental gladiolus are also explored. Overall, the current review provides insight into the applications of basic and advanced biotechnological tools for gladiolus improvement.
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Affiliation(s)
- Mukesh Kumar
- College of Horticulture, SVPUAT, Meerut, UP, 250110, India.
| | - Ujjwal Sirohi
- NIPGR, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Manoj Kumar Yadav
- Department of Agriculture Biotechnology, College of Agriculture, SVPUAT, Meerut, UP, 250110, India
| | - Veena Chaudhary
- Department of Chemistry, Meerut College, Meerut, 250002, India
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2
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Hou M, Opedal ØH, Zhao ZG. Sexually concordant selection on floral traits despite greater opportunity for selection through male fitness. THE NEW PHYTOLOGIST 2024; 241:926-936. [PMID: 37899633 DOI: 10.1111/nph.19370] [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: 09/11/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Pollinators are important drivers of floral trait evolution, yet plant populations are not always perfectly adapted to their pollinators. Such apparent maladaptation may result from conflicting selection through male and female sexual functions in hermaphrodites. We studied sex-specific mating patterns and phenotypic selection on floral traits in Aconitum gymnandrum. After genotyping 1786 offspring, we partitioned individual fitness into sex-specific selfed and outcrossed components and estimated phenotypic selection acting through each. Relative fitness increased with increasing mate number, and more so for male function. This led to greater opportunity for selection through outcrossed male fitness, though patterns of phenotypic selection on floral traits tended to be similar, and with better support for selection through female rather than male fitness components. We detected directional selection through one or more fitness component for larger flower number, larger flowers, and more negative nectar gradients within inflorescences. Our results are consistent with Bateman's principles for sex-specific mating patterns and illustrate that, despite the expected difference in opportunity for selection, patterns of variation in selection across traits can be rather similar for the male and female sexual functions. These results shed new light on the effect of sexual selection on the evolution of floral traits.
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Affiliation(s)
- Meng Hou
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
- Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102, Changchun, China
| | | | - Zhi-Gang Zhao
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
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3
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Rodríguez-Otero C, Hedrén M, Friberg M, Opedal ØH. Analysis of trait-performance-fitness relationships reveals pollinator-mediated selection on orchid pollination traits. AMERICAN JOURNAL OF BOTANY 2023:e16128. [PMID: 36655508 DOI: 10.1002/ajb2.16128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 07/24/2022] [Accepted: 08/01/2022] [Indexed: 06/17/2023]
Abstract
PREMISE The role of pollinators in evolutionary floral divergence has spurred substantial effort into measuring pollinator-mediated phenotypic selection and its variation in space and time. For such estimates, the fitness consequences of pollination processes must be separated from other factors affecting fitness. METHODS We built a fitness function linking phenotypic traits of food-deceptive orchids to female reproductive success by including pollinator visitation and pollen deposition as intermediate performance components and used the fitness function to estimate the strength of pollinator-mediated selection through female reproductive success. We also quantified male performance as pollinarium removal and assessed similarity in trait effects on male and female performance. RESULTS The proportion of plants visited at least once by an effective pollinator was moderate to high, ranging from 53.7% to 85.1%. Tall, many-flowered plants were often more likely to be visited and pollinated. Given effective pollination, pollen deposition onto stigmas tended to be more likely for taller plants. Pollen deposition further depended on traits affecting the physical fit of pollinators to flowers (flower size, spur length), though the exact relationships varied in time and space. Using the fitness function to assess pollinator-mediated selection through female reproductive success acting on multiple traits, we found that selection varied detectably among taxa after accounting for sampling uncertainty. Across taxa, selection on most traits was stronger on average and more variable when pollination was less reliable. CONCLUSIONS These results support pollination-related trait-performance-fitness relationships and thus pollinator-mediated selection on traits functionally involved in the pollination process.
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Affiliation(s)
| | - Mikael Hedrén
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
| | - Magne Friberg
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
| | - Øystein H Opedal
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
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4
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Koski MH. Pollinators exert selection on floral traits in a pollen-limited, narrowly endemic spring ephemeral. AMERICAN JOURNAL OF BOTANY 2023; 110:e16101. [PMID: 36371765 PMCID: PMC10108127 DOI: 10.1002/ajb2.16101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen-limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen-limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor. METHODS I measured pollen limitation in T. discolor across two years and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits. RESULTS Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits. CONCLUSIONS Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits.
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Affiliation(s)
- Matthew H. Koski
- Department of Biological SciencesClemson UniversityClemsonSouth Carolina29634USA
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5
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Simón‐Porcar VI, Muñoz‐Pajares AJ, de Castro A, Arroyo J. Direct evidence supporting Darwin's hypothesis of cross-pollination promoted by sex organ reciprocity. THE NEW PHYTOLOGIST 2022; 235:2099-2110. [PMID: 35596603 PMCID: PMC9546006 DOI: 10.1111/nph.18266] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/09/2022] [Indexed: 05/28/2023]
Abstract
The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar-polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity). We used paternity analyses in experimental populations of a stylar-dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions. The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection. We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.
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Affiliation(s)
| | - A. Jesús Muñoz‐Pajares
- Department of GeneticsUniversity of GranadaE‐18071GranadaSpain
- Research Centre in Biodiversity and Genetic Resources (CIBIO)Campus Agrário de Vairão4485‐661VairãoPortugal
| | - Alejandra de Castro
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
| | - Juan Arroyo
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
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Cozzolino S, Scopece G, Lussu M, Cortis P, Schiestl FP. Do floral and ecogeographic isolation allow the co-occurrence of two ecotypes of Anacamptis papilionacea (Orchidaceae)? Ecol Evol 2021; 11:9917-9931. [PMID: 34367549 PMCID: PMC8328454 DOI: 10.1002/ece3.7432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 11/08/2022] Open
Abstract
Ecotypes are relatively frequent in flowering plants and considered central in ecological speciation as local adaptation can promote the insurgence of reproductive isolation. Without geographic isolation, gene flow usually homogenizes the allopatrically generated phenotypic and ecological divergences, unless other forms of reproductive isolation keep them separated. Here, we investigated two orchid ecotypes with marked phenotypic floral divergence that coexist in contact zones. We found that the two ecotypes show different ecological habitat preferences with one being more climatically restricted than the other. The ecotypes remain clearly morphologically differentiated both in allopatry and in sympatry and differed in diverse floral traits. Despite only slightly different flowering times, the two ecotypes achieved floral isolation thanks to different pollination strategies. We found that both ecotypes attract a wide range of insects, but the ratio of male/female attracted by the two ecotypes was significantly different, with one ecotype mainly attracts male pollinators, while the other mainly attracts female pollinators. As a potential consequence, the two ecotypes show different pollen transfer efficiency. Experimental plots with pollen staining showed a higher proportion of intra- than interecotype movements confirming floral isolation between ecotypes in sympatry while crossing experiments excluded evident postmating barriers. Even if not completely halting the interecotypes pollen flow in sympatry, such incipient switch in pollination strategy between ecotypes may represent a first step on the path toward evolution of sexual mimicry in Orchidinae.
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Affiliation(s)
| | - Giovanni Scopece
- Department of BiologyUniversity Federico II of NaplesNapoliItaly
| | - Michele Lussu
- Department of Life and Environmental SciencesUniversity of CagliariCagliariItaly
- Istituto Regionale per la Floricoltura (IRF)SanremoItaly
| | - Pierluigi Cortis
- Department of Life and Environmental SciencesUniversity of CagliariCagliariItaly
| | - Florian P. Schiestl
- Department of Systematic and Evolutionary Botany and Botanical GardensUniversity of ZurichZurichSwitzerland
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7
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Orsucci M, Sicard A. Flower evolution in the presence of heterospecific gene flow and its contribution to lineage divergence. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:971-989. [PMID: 33537708 DOI: 10.1093/jxb/eraa549] [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: 08/10/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
The success of species depends on their ability to exploit ecological resources in order to optimize their reproduction. However, species are not usually found within single-species ecosystems but in complex communities. Because of their genetic relatedness, closely related lineages tend to cluster within the same ecosystem, rely on the same resources, and be phenotypically similar. In sympatry, they will therefore compete for the same resources and, in the case of flowering plants, exchange their genes through heterospecific pollen transfer. These interactions, nevertheless, pose significant challenges to species co-existence because they can lead to resource limitation and reproductive interference. In such cases, divergent selective pressures on floral traits will favour genotypes that isolate or desynchronize the reproduction of sympatric lineages. The resulting displacement of reproductive characters will, in turn, lead to pre-mating isolation and promote intraspecific divergence, thus initiating or reinforcing the speciation process. In this review, we discuss the current theoretical and empirical knowledge on the influence of heterospecific pollen transfer on flower evolution, highlighting its potential to uncover the ecological and genomic constraints shaping the speciation process.
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Affiliation(s)
- Marion Orsucci
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Adrien Sicard
- Department of Plant Biology, Swedish University of Agricultural, Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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8
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Chapurlat E, Le Roncé I, Ågren J, Sletvold N. Divergent selection on flowering phenology but not on floral morphology between two closely related orchids. Ecol Evol 2020; 10:5737-5747. [PMID: 32607187 PMCID: PMC7319237 DOI: 10.1002/ece3.6312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 11/08/2022] Open
Abstract
Closely related species often differ in traits that influence reproductive success, suggesting that divergent selection on such traits contribute to the maintenance of species boundaries. Gymnadenia conopsea ss. and Gymnadenia densiflora are two closely related, perennial orchid species that differ in (a) floral traits important for pollination, including flowering phenology, floral display, and spur length, and (b) dominant pollinators. If plant-pollinator interactions contribute to the maintenance of trait differences between these two taxa, we expect current divergent selection on flowering phenology and floral morphology between the two species. We quantified phenotypic selection via female fitness in one year on flowering start, three floral display traits (plant height, number of flowers, and corolla size) and spur length, in six populations of G. conopsea s.s. and in four populations of G. densiflora. There was indication of divergent selection on flowering start in the expected direction, with selection for earlier flowering in two populations of the early-flowering G. conopsea s.s. and for later flowering in one population of the late-flowering G. densiflora. No divergent selection on floral morphology was detected, and there was no significant stabilizing selection on any trait in the two species. The results suggest ongoing adaptive differentiation of flowering phenology, strengthening this premating reproductive barrier between the two species. Synthesis: This study is among the first to test whether divergent selection on floral traits contribute to the maintenance of species differences between closely related plants. Phenological isolation confers a substantial potential for reproductive isolation, and divergent selection on flowering time can thus greatly influence reproductive isolation and adaptive differentiation.
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Affiliation(s)
- Elodie Chapurlat
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Iris Le Roncé
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
- Master BioSciencesÉcole Normale Supérieure de LyonUniversité Claude Bernard Lyon 1Université de LyonLyonFrance
| | - Jon Ågren
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Nina Sletvold
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
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9
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Minnaar C, de Jager ML, Anderson B. Intraspecific divergence in floral-tube length promotes asymmetric pollen movement and reproductive isolation. THE NEW PHYTOLOGIST 2019; 224:1160-1170. [PMID: 31148172 DOI: 10.1111/nph.15971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
The causative link between phenotypic divergence and reproductive isolation is an important but poorly understood part of ecological speciation. We studied the effects of floral-tube length variation on pollen placement/receipt positions and reproductive isolation. In a population of Lapeirousia anceps (Iridaceae) with bimodal floral-tube lengths, we labelled pollen of short- and long-tubed flowers with different colour fluorescent nanoparticles (quantum dots). This enabled us to map pollen placement by long- and short-tubed flowers on the only floral visitor, a long-proboscid fly. Furthermore, it allowed us to quantify pollen movement within and between short- and long-tubed flowers. Short- and long-tubed flowers placed pollen on different parts of the pollinator, and long-tubed flowers placed more pollen per visit than short-tubed flowers. This resulted in assortative pollen receipt (most pollen received comes from the same phenotype) and strong but asymmetric reproductive isolation, where short-tubed plants are more reproductively isolated than long-tubed plants. These results suggest that floral-tube length divergence can promote mechanical isolation in plants through divergence in pollen placement sites on pollinators. Consequently, in concert with other reproductive isolation mechanisms, selection for differences in floral-tube length can play an important role in ecological speciation of plants.
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Affiliation(s)
- Corneile Minnaar
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Marinus L de Jager
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Bruce Anderson
- Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
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10
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Kahnt B, Hattingh WN, Theodorou P, Wieseke N, Kuhlmann M, Glennon KL, Niet T, Paxton R, Cron GV. Should I stay or should I go? Pollinator shifts rather than cospeciation dominate the evolutionary history of South African
Rediviva
bees and their
Diascia
host plants. Mol Ecol 2019; 28:4118-4133. [DOI: 10.1111/mec.15154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/19/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Belinda Kahnt
- General Zoology Institute of Biology Martin‐Luther‐University Halle‐Wittenberg Halle (Saale) Germany
| | - Wesley N. Hattingh
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Braamfontein South Africa
| | - Panagiotis Theodorou
- General Zoology Institute of Biology Martin‐Luther‐University Halle‐Wittenberg Halle (Saale) Germany
| | - Nicolas Wieseke
- Institute for Informatics University of Leipzig Leipzig Germany
| | - Michael Kuhlmann
- Zoological Museum Kiel University Kiel Germany
- Department of Life Sciences Natural History Museum London UK
| | - Kelsey L. Glennon
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Braamfontein South Africa
| | - Timotheüs Niet
- School of Life Sciences Centre for Functional Biodiversity University of Kwazulu‐Natal Pietermaritzburg South Africa
| | - Robert Paxton
- General Zoology Institute of Biology Martin‐Luther‐University Halle‐Wittenberg Halle (Saale) Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
| | - Glynis V. Cron
- School of Animal, Plant and Environmental Sciences University of the Witwatersrand Braamfontein South Africa
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11
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Olito C, Abbott JK, Jordan CY. The interaction between sex-specific selection and local adaptation in species without separate sexes. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170426. [PMID: 30150224 PMCID: PMC6125720 DOI: 10.1098/rstb.2017.0426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 11/12/2022] Open
Abstract
Local adaptation in hermaphrodite species can be based on a variety of fitness components, including survival, as well as both female and male sex-functions within individuals. When selection via female and male fitness components varies spatially (e.g. due to environmental heterogeneity), local adaptation will depend, in part, on variation in selection through each fitness component, and the extent to which genetic trade-offs between sex-functions maintain genetic variation necessary for adaptation. Local adaptation will also depend on the hermaphrodite mating system because self-fertilization alters several key factors influencing selection and the maintenance of genetic variance underlying trade-offs between the sex-functions (sexually antagonistic polymorphism). As a first step to guide intuition regarding sex-specific adaptation in hermaphrodites, we develop a simple theoretical model incorporating the essential features of hermaphrodite mating and adaptation in a spatially heterogeneous environment, and explore the interaction between sex-specific selection, self-fertilization and local adaptation. Our results suggest that opportunities for sex-specific local adaptation in hermaphrodites depend strongly on the extent of self-fertilization and inbreeding depression. Using our model as a conceptual framework, we provide a broad overview of the literature on sex-specific selection and local adaptation in hermaphroditic plants and animals, emphasizing promising future directions in light of our theoretical predictions.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Colin Olito
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Victoria 3800, Australia
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Jessica K Abbott
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Crispin Y Jordan
- School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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12
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Lebel M, Obolski U, Hadany L, Sapir Y. Pollinator-mediated selection on floral size and tube color in Linum pubescens: Can differential behavior and preference in different times of the day maintain dimorphism? Ecol Evol 2018; 8:1096-1106. [PMID: 29375782 PMCID: PMC5773291 DOI: 10.1002/ece3.3683] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 10/01/2017] [Accepted: 11/08/2017] [Indexed: 12/16/2022] Open
Abstract
Diversity of flower traits is often proposed as the outcome of selection exerted by pollinators. Positive directional pollinator-mediated selection on floral size has been widely shown to reduce phenotypic variance. However, the underlying mechanism of maintaining within-population floral color polymorphism is poorly understood. Divergent selection, mediated by different pollinators or by both mutualists and antagonists, may create and maintain such polymorphism, but it has rarely been shown to result from differential behavior of one pollinator. We tested whether different behaviors of the same pollinators in morning and evening are associated with dimorphic floral trait in Linum pubescens, a Mediterranean annual plant that exhibits variable within-population frequencies of dark- and light-colored flower tubes. Usia bicolor bee-flies, the major pollinators of L. pubescens, are mostly feeding in the flower in the morning, while in the evening they are mostly visiting the flowers for mating. In 2 years of studying L. pubescens in a single large population in the Carmel, Israel, we found in one year that dark-centered flowers received significantly higher fraction of visits in the morning. Fitness was positively affected by number of visits, but no fitness differences were found between tube-color morphs, suggesting that both morphs have similar pollination success. Using mediation analysis, we found that flower size was under positive directional pollinator-mediated selection in both years, but pollinator behavior did not explain entirely this selection, which was possibly mediated also by other agents, such as florivores or a-biotic stresses. While most pollinator-mediated selection studies show that flower size signals food reward, in L. pubescens, it may also signal for mating place, which may drive positive selection. While flower size found to be under pollinator-mediated selection in L. pubescens, differential behavior of the pollinators in morning and evening did not seem to explain flower color polymorphism.
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Affiliation(s)
- Merav Lebel
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- School of Plant Sciences and Food SecurityTel Aviv UniversityTel AvivIsrael
- Present address:
Science DivisionNature‐Parks AuthorityJerusalemIsrael
| | - Uri Obolski
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- Present address:
Department of ZoologyUniversity of OxfordOxfordUK
| | - Lilach Hadany
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
| | - Yuval Sapir
- The Botanical GardenTel Aviv UniversityTel AvivIsrael
- School of Plant Sciences and Food SecurityTel Aviv UniversityTel AvivIsrael
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13
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Anderson B, Pauw A, Cole WW, Barrett SCH. Pollination, mating and reproductive fitness in a plant population with bimodal floral-tube length. J Evol Biol 2016; 29:1631-42. [PMID: 27206242 DOI: 10.1111/jeb.12899] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 05/15/2016] [Accepted: 05/16/2016] [Indexed: 01/19/2023]
Abstract
Mating patterns and natural selection play important roles in determining whether genetic polymorphisms are maintained or lost. Here, we document an atypical population of Lapeirousia anceps (Iridaceae) with a bimodal distribution of floral-tube length and investigate the reproductive mechanisms associated with this pattern of variation. Flowers were visited exclusively by the long-proboscid fly Moegistorhynchus longirostris (Nemestrinidae), which exhibited a unimodal distribution of proboscis length and displayed a preference for long-tubed phenotypes. Despite being visited by a single pollinator species, allozyme markers revealed significant genetic differentiation between open-pollinated progeny of long- and short-tubed phenotypes suggesting mating barriers between them. We obtained direct evidence for mating barriers between the floral-tube phenotypes through observations of pollinator foraging, controlled hand pollinations and measurements of pollen competition and seed set. Intermediate tube-length phenotypes produced fewer seeds in the field than either long- or short-tubed phenotypes. Although floral-tube length bimodality may not be a stable state over long timescales, reproductive barriers to mating and low 'hybrid' fitness have the potential to contribute to the maintenance of this state in the short term.
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Affiliation(s)
- B Anderson
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - A Pauw
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - W W Cole
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - S C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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Sinn BT, Kelly LM, Freudenstein JV. Putative floral brood-site mimicry, loss of autonomous selfing, and reduced vegetative growth are significantly correlated with increased diversification in Asarum (Aristolochiaceae). Mol Phylogenet Evol 2015; 89:194-204. [DOI: 10.1016/j.ympev.2015.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 11/26/2022]
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15
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Sun M, Schlüter PM, Gross K, Schiestl FP. Floral isolation is the major reproductive barrier between a pair of rewarding orchid sister species. J Evol Biol 2015; 28:117-29. [PMID: 25382492 DOI: 10.1111/jeb.12544] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 11/04/2014] [Indexed: 11/30/2022]
Abstract
The crucial role of reproductive isolation in speciation has long been recognized; however, a limited number of studies quantify different isolation barriers and embed reproductive isolation in a phylogenetic context. In this study, we investigate reproductive isolation between the often sympatrically occurring orchid species, Gymnadenia conopsea and G. odoratissima. We examine the phylogenetic relationship between the two species and analyse floral isolation, fruit set and seed viability from interspecies crosses, as well as the ploidy level. Additionally, we quantify interspecies differences in floral signals and morphology. The results suggest that the two species have a sister-species relationship. In terms of reproductive isolation, we found complete floral isolation between the two species, but little to no post-pollination isolation; the species also mostly had the same ploidy level in the studied populations. We also show clear distinctions in floral signals, as well as in floral size and spur length. We propose that respective adaptation to short- vs. long-tongued pollinators was the driver of speciation in the here studied Gymnadenia species. Our study supports the key role of floral isolation in orchid speciation and shows that floral isolation is not restricted to highly specialized pollination systems, but can also occur between species with less specialized pollination.
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Affiliation(s)
- M Sun
- Institute of Systematic Botany, University of Zürich, Zürich, Switzerland
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16
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Jordan CY, Connallon T. Sexually antagonistic polymorphism in simultaneous hermaphrodites. Evolution 2014; 68:3555-69. [PMID: 25311368 DOI: 10.1111/evo.12536] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/09/2014] [Indexed: 12/22/2022]
Abstract
In hermaphrodites, pleiotropic genetic trade-offs between female and male reproductive functions can lead to sexually antagonistic (SA) selection, where individual alleles have conflicting fitness effects on each sex function. Although an extensive theory of SA selection exists for dioecious species, these results have not been generalized to hermaphrodites. We develop population genetic models of SA selection in simultaneous hermaphrodites, and evaluate effects of dominance, selection on each sex function, self-fertilization, and population size on the maintenance of polymorphism. Under obligate outcrossing, hermaphrodite model predictions converge exactly with those of dioecious populations. Self-fertilization in hermaphrodites generates three points of divergence with dioecious theory. First, opportunities for stable polymorphism decline sharply and become less sensitive to dominance with increased selfing. Second, selfing introduces an asymmetry in the relative importance of selection through male versus female reproductive functions, expands the parameter space favorable for the evolutionary invasion of female-beneficial alleles, and restricts invasion criteria for male-beneficial alleles. Finally, contrary to models of unconditionally beneficial alleles, selfing decreases genetic hitchhiking effects of invading SA alleles, and should therefore decrease these population genetic signals of SA polymorphisms. We discuss implications of SA selection in hermaphrodites, including its potential role in the evolution of "selfing syndromes."
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Affiliation(s)
- Crispin Y Jordan
- Ashworth Laboratories, Institute of Evolutionary Biology, The University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom.
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Raimundo RLG, Gibert JP, Hembry DH, Guimarães PR. Conflicting selection in the course of adaptive diversification: the interplay between mutualism and intraspecific competition. Am Nat 2014; 183:363-75. [PMID: 24561599 DOI: 10.1086/674965] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Adaptive speciation can occur when a population undergoes assortative mating and disruptive selection caused by frequency-dependent intraspecific competition. However, other interactions, such as mutualisms based on trait matching, may generate conflicting selective pressures that constrain species diversification. We used individual-based simulations to explore how different types of mutualism affect adaptive diversification. A magic trait was assumed to simultaneously mediate mate choice, intraspecific competition, and mutualisms. In scenarios of intimate, specialized mutualisms, individuals interact with one or few individual mutualistic partners, and diversification is constrained only if the mutualism is obligate. In other scenarios, increasing numbers of different partners per individual limit diversification by generating stabilizing selection. Stabilizing selection emerges from the greater likelihood of trait mismatches for rare, extreme phenotypes than for common intermediate phenotypes. Constraints on diversification imposed by increased numbers of partners decrease if the trait matching degree has smaller positive effects on fitness. These results hold after the relaxation of various assumptions. When trait matching matters, mutualism-generated stabilizing selection would thus often constrain diversification in obligate mutualisms, such as ant-myrmecophyte associations, and in low-intimacy mutualisms, including plant-seed disperser systems. Hence, different processes, such as trait convergence favoring the incorporation of nonrelated species, are needed to explain the higher richness of low-intimacy assemblages--shown here to be up to 1 order of magnitude richer than high-intimacy systems.
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Affiliation(s)
- Rafael L G Raimundo
- Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Travessa 14, no. 321, 05508-900 Sao Paulo SP, Brazil
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18
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Van der Niet T, Peakall R, Johnson SD. Pollinator-driven ecological speciation in plants: new evidence and future perspectives. ANNALS OF BOTANY 2014; 113:199-211. [PMID: 24418954 PMCID: PMC3890394 DOI: 10.1093/aob/mct290] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 11/17/2013] [Indexed: 05/07/2023]
Abstract
BACKGROUND The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. SCOPE This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of 'pollination ecotypes', (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation.
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Affiliation(s)
- Timotheüs Van der Niet
- Naturalis Biodiversity Center, P.O. Box 9514, 2300 RA, Leiden, The Netherlands
- Leiden University, Section Botany, P.O. Box 9514, 2300 RA, Leiden, The Netherlands
- School of Life Sciences, University of KwaZulu Natal, P/Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
| | - Rod Peakall
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Steven D. Johnson
- School of Life Sciences, University of KwaZulu Natal, P/Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
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19
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Dai C, Galloway LF. Sexual selection in a hermaphroditic plant through female reproductive success. J Evol Biol 2013; 26:2622-32. [DOI: 10.1111/jeb.12254] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/22/2013] [Accepted: 08/26/2013] [Indexed: 11/29/2022]
Affiliation(s)
- C. Dai
- Department of Biology; University of Virginia; Charlottesville VA USA
- School of Resources and Environmental Science; Hubei University; Wuhan China
| | - L. F. Galloway
- Department of Biology; University of Virginia; Charlottesville VA USA
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20
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Zhang F, Hui C, Pauw A. Adaptive divergence in Darwin's race: how coevolution can generate trait diversity in a pollination system. Evolution 2012; 67:548-60. [PMID: 23356625 DOI: 10.1111/j.1558-5646.2012.01796.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding how reciprocal selection shapes interacting species in Darwin's coevolutionary race is a captivating pursuit in evolutionary ecology. Coevolving traits can potentially display following three patterns: (1) geographical variation in matched traits, (2) bias in trait matching, and (3) bimodal distribution of a trait in certain populations. Based on the framework of adaptive dynamics, we present an evolutionary model for a coevolving pollination system involving the long-proboscid fly (Moegistorhynchus longirostris) and the long-tubed iris (Lapeirousia anceps). The model successfully demonstrates that Darwin's hypothesis can lead to all three patterns if costs are involved. Geographical variation in matched traits could be driven by geographical variation in environmental factors that affect the cost rate of trait escalation. Unequal benefits derived from the interaction by the fly and the flower could potentially cause the bias in trait matching of the system. Different cost rates to trait elongation incurred by the two species and weak assortative interactions in the coevolutionary race can drive divergent selection (i.e., an evolutionary branching) that leads to the bimodal distribution of traits. Overall, the model highlights the importance of assortative interactions and the balance of costs incurred by coevolving species as factors determining the eventual phenotypic outcome of coevolutionary interactions.
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Affiliation(s)
- Feng Zhang
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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Valente LM, Manning JC, Goldblatt P, Vargas P. Did Pollination Shifts Drive Diversification in Southern African Gladiolus? Evaluating the Model of Pollinator-Driven Speciation. Am Nat 2012; 180:83-98. [DOI: 10.1086/666003] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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ROS PETRA, ELLIS ALLANG, ANDERSON BRUCE. Maintenance of sympatric floral tube-length variation in a Cape irid. Biol J Linn Soc Lond 2011. [DOI: 10.1111/j.1095-8312.2011.01705.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sapir Y, Armbruster WS. Pollinator-mediated selection and floral evolution: from pollination ecology to macroevolution. THE NEW PHYTOLOGIST 2010; 188:303-306. [PMID: 20941844 DOI: 10.1111/j.1469-8137.2010.03467.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Yuval Sapir
- The Botanical Garden, Department of Plant Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel.
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