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Yue J, Yan Z, Liu W, Liu J, Yang D. A visual pollination mechanism of a new specialized pollinating weevil-plant reciprocity system. FRONTIERS IN PLANT SCIENCE 2024; 15:1432263. [PMID: 39220015 PMCID: PMC11362035 DOI: 10.3389/fpls.2024.1432263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024]
Abstract
Introduction Pollinating flower-consuming mutualisms are considered exemplary models for studying coevolution due to their rarity. Visual cues are considered to have a major role in facilitating the evolution of floral patterns in these systems. We present a new specialized pollinating flower-consuming mutualism from the plant Wurfbainia villosa, which is a traditional Chinese herbal medicine, by a pollinating weevil, Xenysmoderes sp. Methods In this study, We utilized monochrome plates for binary-choice tests to determine weevil color preferences, conducted behavioral choice experiments, using trackballs, photographed flowers and weevils, and employed blue sticky boards to attract weevils in the field. Results Tests were conducted using colorpreferring weevils in both indoor and outdoor field systems, and validation experiments were performed. Behavioral tests were conducted to investigate the role of the visual cues in the pollinator attraction of W. villosa, which is a selfcompatible insect-pollinated plant that relies primarily on the Xenysmoderes sp. weevil for pollination due to its specialized gynandrium-like structure. Behavioral tests demonstrated that a blue color wavelength of 480 nm and the blue color system, as along with the UV-style pattern of the flowers, particularly the parts with specialized gynandrium-like structures in the labellum, were significantly attractive to both male and female weevils. These results were further confirmed through the field blue sticky board trap method. Discussion These findings indicated that the interaction between W. villosa and Xenysmoderes sp. weevil was a novel symbiotic relationship involving pollinator flower consumption. Additionally, Wurfbainia villosa flowers developed specific visual cues of UV patterns and specialized structures that played a crucial role in attracting pollinators.
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Affiliation(s)
- Jianjun Yue
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
- School of Traditional Dai-Thai Medicine, West Yunnan University of Applied Sciences, Jinghong, China
| | - Zhen Yan
- Yunnan Key Laboratory of Southern Medicine Utilization, Institute of Medicinal Plant Development Yunnan Branch, Chinese Academy of Medical Sciences and Peking Union Medical College, Jinghong, China
| | - Wei Liu
- School of Traditional Dai-Thai Medicine, West Yunnan University of Applied Sciences, Jinghong, China
| | - Ju Liu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Depo Yang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
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2
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Heywood JS, Michalski JS, McCann BK, Andres KJ, Hall AR, Hartman AD, Middleton TC, Chiles A, Dewey SE, Miller CA. The potential for floral evolution in response to competing selection pressures following the loss of hawkmoth pollination in Ruellia humilis. AMERICAN JOURNAL OF BOTANY 2022; 109:1875-1892. [PMID: 36063430 DOI: 10.1002/ajb2.16063] [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: 01/05/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
PREMISE In the absence of hawkmoth pollinators, chasmogamous (CH) flowers of Ruellia humilis self-pollinate by two secondary mechanisms. Other floral visitors might exert selection on CH floral traits to restore outcrossing, but at the same time preferential predation of CH seeds generates selection to increase the allocation of resources to cleistogamous (CL) flowers. METHODS To assess the potential for an evolutionary response to these competing selection pressures, we estimated additive genetic variances ( σ A 2 ${\sigma }_{{\rm{A}}}^{2}$ ) and covariances for 14 reproductive traits and three fitness components in a Missouri population lacking hawkmoth pollinators. RESULTS We found significant σ A 2 ${\sigma }_{{\rm{A}}}^{2}$ for all 11 floral traits and two measures of resource allocation to CL flowers, indicating the potential for a short-term response to selection on most reproductive traits. Selection generated by seed predators is predicted to increase the percentage of CL flowers by 0.24% per generation, and mean stigma-anther separation is predicted to decrease as a correlated response, increasing the fraction of plants that engage in prior selfing. However, the initial response to this selection is opposed by strong directional dominance. CONCLUSIONS The predicted evolutionary decrease in the number of CH flowers available for potential outcrossing, combined with the apparent preclusion of potential diurnal pollinators by the pollen-harvesting activities of sweat bees, suggest that 100% cleistogamy is the likely outcome of evolution in the absence of hawkmoths. However, rare mutations with large effects, such as delaying budbreak until after sunrise, could provide pathways for the restoration of outcrossing that are not reachable by gradual quantitative-genetic evolution.
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Affiliation(s)
- John S Heywood
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Joseph S Michalski
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Braden K McCann
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Kara J Andres
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
- Department of Ecology and Evolutionary Biology, Cornell University, 215 Tower Rd., Ithaca, NY, 14853, USA
| | - Allison R Hall
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Amber D Hartman
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Tessa C Middleton
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Amelia Chiles
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Sarah E Dewey
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
| | - Cay A Miller
- Biology Department, Missouri State University, 901 S National Ave., Springfield, MO, 65897, USA
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Lin Y, Laosatit K, Liu J, Chen J, Yuan X, Somta P, Chen X. The mungbean VrP locus encoding MYB90, an R2R3-type MYB protein, regulates anthocyanin biosynthesis. FRONTIERS IN PLANT SCIENCE 2022; 13:895634. [PMID: 35937322 PMCID: PMC9355716 DOI: 10.3389/fpls.2022.895634] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/27/2022] [Indexed: 05/30/2023]
Abstract
Anthocyanins are water-soluble pigments present in several tissues/parts of plants. The pigments provide color and are wildly known for health benefits for human, insect attraction for plant pollination, and stress resistance in plants. Anthocyanin content variations in mungbean [Vigna radiata (L.) Wilczek] were first noticed a long time ago, but the genetic mechanism controlling the anthocyanins in mungbean remains unknown. An F2 population derived from the cross between purple-hypocotyl (V2709) and green-hypocotyl (Sulv1) mungbeans was used to map the VrP locus controlling purple hypocotyl. The VrP locus was mapped to a 78.9-kb region on chromosome 4. Sequence comparison and gene expression analysis identified an R2R3-MYB gene VrMYB90 as the candidate gene for the VrP locus. Haplotype analysis using 124 mungbean accessions suggested that 10 single nucleotide polymorphisms (SNPs) in exon 3 may lead to an abolished expression of VrMYB90 and an absence of anthocyanin accumulation in the hypocotyl of Sulv1 and KPS2. The overexpression of VrMYB90 in mungbean hairy root, tobacco leaf, and Arabidopsis resulted in anthocyanin accumulation (purple color). Gene expression analysis demonstrated that VrMYB90 regulated anthocyanin accumulation in the hypocotyl, stem, petiole, and flowers, and the expression was sensitive to light. VrMYB90 protein may upregulate VrDFR encoding dihydroflavonol 4-reductase at the late biosynthesis step of anthocyanins in mungbeans. These results suggest that VrMYB90 is the dominator in the spatiotemporal regulation of anthocyanin biosynthesis. Our results provide insight into the biosynthesis mechanism of anthocyanin and a theoretical basis for breeding mungbeans.
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Affiliation(s)
- Yun Lin
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Kularb Laosatit
- Department of Agronomy, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Kamphaeng Saen, Thailand
| | - Jinyang Liu
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jingbing Chen
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xingxing Yuan
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Prakit Somta
- Department of Agronomy, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Kamphaeng Saen, Thailand
| | - Xin Chen
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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Coetzee A, Seymour CL, Spottiswoode CN. Facilitation and competition shape a geographical mosaic of flower colour polymorphisms. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13851] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Anina Coetzee
- FitzPatrick Institute of African Ornithology Department of Science and Innovation‐National Research Foundation Centre of Excellence University of Cape Town Rondebosch South Africa
| | - Colleen L. Seymour
- FitzPatrick Institute of African Ornithology Department of Science and Innovation‐National Research Foundation Centre of Excellence University of Cape Town Rondebosch South Africa
- South African National Biodiversity InstituteKirstenbosch Research Centre Claremont South Africa
| | - Claire N. Spottiswoode
- FitzPatrick Institute of African Ornithology Department of Science and Innovation‐National Research Foundation Centre of Excellence University of Cape Town Rondebosch South Africa
- Department of Zoology University of Cambridge Cambridge UK
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5
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Johnson IM, Edwards TJ, Johnson SD. Geographical Variation in Flower Color in the Grassland Daisy Gerbera aurantiaca: Testing for Associations With Pollinators and Abiotic Factors. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.676520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Geographical variation in flower color of a plant species may reflect the outcome of selection by pollinators or may reflect abiotic factors such as soil chemistry or neutral processes such as genetic drift. Here we document striking geographical structure in the color of capitula of the endemic South African grassland daisy Gerbera aurantiaca and ask which of these competing explanations best explains this pattern. The color of capitula ranges from predominantly red in the southwest to yellow in the center, with some northern populations showing within-population polymorphism. Hopliine scarab beetles were the most abundant flower visitors in all populations, apart from a yellow-flowered one where honeybees were frequent. In a mixed color population, yellow, orange and red morphs were equally attractive to hopliine beetles and did not differ significantly in terms of fruit set. Beetles were attracted to both red and yellow pan traps, but preferred the latter even at sites dominated by the red morph. We found no strong associations between morph color and abiotic factors, including soil chemistry. Plants in a common garden retained the capitulum color of the source population, even when grown from seed, suggesting that flower color variation is not a result of phenotypic plasticity. These results show that flower color in G. aurantiaca is geographically structured, but the ultimate evolutionary basis of this color variation remains elusive.
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Essenberg CJ. Intraspecific relationships between floral signals and rewards with implications for plant fitness. AOB PLANTS 2021; 13:plab006. [PMID: 33708371 PMCID: PMC7937183 DOI: 10.1093/aobpla/plab006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Within-species variation in traits such as petal size or colour often provides reliable information to pollinators about the rewards offered to them by flowers. In spite of potential disadvantages of allowing pollinators to discriminate against less-rewarding flowers, examples of informative floral signals are diverse in form and widely distributed across plant taxa, apparently having evolved repeatedly in different lineages. Although hypotheses about the adaptive value of providing reward information have been proposed and tested in a few cases, a unified effort to understand the evolutionary mechanisms favouring informative floral signals has yet to emerge. This review describes the diversity of ways in which floral signals can be linked with floral rewards within plant species and discusses the constraints and selective pressures on floral signal-reward relationships. It focuses particularly on how information about floral rewards can influence pollinator behaviour and how those behavioural changes may, in turn, affect plant fitness, selecting either for providing or withholding reward information. Most of the hypotheses about the evolution of floral signal-reward relationships are, as yet, untested, and the review identifies promising research directions for addressing these considerable gaps in knowledge. The advantages and disadvantages of sharing floral reward information with pollinators likely play an important role in floral trait evolution, and opportunities abound to further our understanding of this neglected aspect of floral signalling.
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Nolting KM, Prunier R, Midgley GF, Holsinger KE. Intraspecific trait variation influences physiological performance and fitness in the South Africa shrub genus Protea (Proteaceae). ANNALS OF BOTANY 2021; 127:519-531. [PMID: 32249291 PMCID: PMC7988518 DOI: 10.1093/aob/mcaa060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/03/2020] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Global plant trait datasets commonly identify trait relationships that are interpreted to reflect fundamental trade-offs associated with plant strategies, but often these trait relationships are not identified when evaluating them at smaller taxonomic and spatial scales. In this study we evaluate trait relationships measured on individual plants for five widespread Protea species in South Africa to determine whether broad-scale patterns of structural trait (e.g. leaf area) and physiological trait (e.g. photosynthetic rates) relationships can be detected within natural populations, and if these traits are themselves related to plant fitness. METHODS We evaluated the variance structure (i.e. the proportional intraspecific trait variation relative to among-species variation) for nine structural traits and six physiological traits measured in wild populations. We used a multivariate path model to evaluate the relationships between structural traits and physiological traits, and the relationship between these traits and plant size and reproductive effort. KEY RESULTS While intraspecific trait variation is relatively low for structural traits, it accounts for between 50 and 100 % of the variation in physiological traits. Furthermore, we identified few trait associations between any one structural trait and physiological trait, but multivariate regressions revealed clear associations between combinations of structural traits and physiological performance (R2 = 0.37-0.64), and almost all traits had detectable associations with plant fitness. CONCLUSIONS Intraspecific variation in structural traits leads to predictable differences in individual-level physiological performance in a multivariate framework, even though the relationship of any particular structural trait to physiological performance may be weak or undetectable. Furthermore, intraspecific variation in both structural and physiological traits leads to differences in plant size and fitness. These results demonstrate the importance of considering measurements of multivariate phenotypes on individual plants when evaluating trait relationships and how trait variation influences predictions of ecological and evolutionary outcomes.
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Affiliation(s)
- Kristen M Nolting
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Rachel Prunier
- Department of Biological and Environmental Sciences, Western Connecticut State University, Danbury, CT, USAand
| | - Guy F Midgley
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - Kent E Holsinger
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
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8
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Buide ML, Del Valle JC, Prado-Comesaña A, Narbona E. The effects of pollination, herbivory and autonomous selfing on the maintenance of flower colour variation in Silenelittorea. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:275-284. [PMID: 33179369 DOI: 10.1111/plb.13209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/30/2020] [Indexed: 05/23/2023]
Abstract
Intraspecific flower colour variation has been generally proposed to evolve as a result of selection driven by biotic or abiotic agents. In a polymorphic population of Silene littorea with pink- and white-flowered plants, we studied pollinators, analysed flower colour perception and tested for differences in pollinator visitation. We also experimentally analysed pollinator limitation in fruit and seed set, and the degree of autonomous selfing. The incidence of florivory and leaf herbivory was compared over 3-4 years. Silene littorea is mainly pollinated by bees and butterflies. Pollinators preferred pink flowers, which did not show pollinator limitation. On the contrary, white flowers showed pollinator limitation in fruit set. White-flowered plants had less floral display and higher levels of florivory than pink plants. Flower colour morphs of S. littorea can reproduce in the absence of pollinators by autonomous selfing, setting 20% and 12% of fruit and seeds in the pink morph and 27% and 20% in the white morph, respectively. Fruit set of white flowers produced by autonomous selfing did not differ from open-pollinated flowers. In conclusion, S. littorea is pollinated by insects of different orders that more frequently visit pink flowers, which is reflected in pollinator limitation of fruit set in white flowers. Moreover, this species has a mixed mating system in which both colour morphs can reproduce in the absence of pollinators by autonomous selfing, although white flowers mainly produce fruits by autogamy. We suggest that reproductive assurance by autonomous selfing helps to maintain flower colour polymorphism in this population.
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Affiliation(s)
- M L Buide
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - J C Del Valle
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
| | - A Prado-Comesaña
- Department of Analytical and Food Chemistry, University of Vigo, Vigo, Spain
| | - E Narbona
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain
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Sapir Y, Gallagher MK, Senden E. What Maintains Flower Colour Variation within Populations? Trends Ecol Evol 2021; 36:507-519. [PMID: 33663870 DOI: 10.1016/j.tree.2021.01.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 01/24/2021] [Accepted: 01/26/2021] [Indexed: 02/06/2023]
Abstract
Natural selection acts on phenotypic trait variation. Understanding the mechanisms that create and maintain trait variation is fundamental to understanding the breadth of diversity seen on Earth. Flower colour is among the most conspicuous and highly diverse traits in nature. Most flowering plant populations have uniform floral colours, but a minority exhibit within-population colour variation, either discrete (polymorphic) or continuous. Colour variation is commonly maintained by balancing selection through multiple pollinators, opposing selection regimes, or fluctuating selection. Variation can also be maintained by heterozygote advantage or frequency-dependent selection. Neutral processes, or a lack of selection, may maintain variation, although this remains largely untested. We suggest several prospective research directions that may provide insight into the evolutionary drivers of trait variation.
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Affiliation(s)
- Yuval Sapir
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
| | - M Kate Gallagher
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Esther Senden
- The Botanical Garden, School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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10
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Rodríguez-Castañeda NL, Ortiz PL, Arista M, Narbona E, Buide ML. Indirect Selection on Flower Color in Silene littorea. FRONTIERS IN PLANT SCIENCE 2020; 11:588383. [PMID: 33424884 PMCID: PMC7785944 DOI: 10.3389/fpls.2020.588383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/25/2020] [Indexed: 05/07/2023]
Abstract
Flower color, as other floral traits, may suffer conflicting selective pressures mediated by both mutualists and antagonists. The maintenance of intraspecific flower color variability has been usually explained as a result of direct selection by biotic agents. However, flower color might also be under indirect selection through correlated traits, since correlations among flower traits are frequent. In this study, we aimed to find out how flower color variability is maintained in two nearby populations of Silene littorea that consistently differ in the proportions of white-flowered plants. To do that, we assessed natural selection on floral color and correlated traits by means of phenotypic selection analysis and path analysis. Strong directional selection on floral display and flower production was found in both populations through either male or female fitness. Flower color had a negative indirect effect on the total male and female fitness in Melide population, as plants with lighter corollas produced more flowers. In contrast, in Barra population, plants with darker corollas produced more flowers and have darker calices, which in turn were selected. Our results suggest that the prevalence of white-flowered plants in Melide and pink-flowered plants in Barra is a result of indirect selection through correlated flower traits and not a result of direct selection of either pollinators or herbivores on color.
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Affiliation(s)
| | - Pedro L. Ortiz
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Montserrat Arista
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Eduardo Narbona
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
| | - Mª Luisa Buide
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
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11
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Johnson SD, von Witt CG, Anderson B. Floral Color Variation in Drosera cistiflora Is Associated With Switches in Beetle Pollinator Assemblages. FRONTIERS IN PLANT SCIENCE 2020; 11:606259. [PMID: 33312188 PMCID: PMC7704453 DOI: 10.3389/fpls.2020.606259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
Floral color shifts are thought to be one of the most common evolutionary transitions in plants, and pollinators are often proposed as important selective agents driving these transitions. However, shifts in flower color can also be related to neutral genetic processes or pleiotropy linked with selection via other biotic agents or abiotic factors. Here we ask whether abiotic factors or pollinators provide the best explanation for divergence in flower color among populations of the sundew Drosera cistiflora s.l. (Droseraceae). This species complex in the Greater Cape Floristic Region contains at least five distinctive floral color forms. Abiotic factors do not appear to play a significant role in color determination, as the forms are not specific to a single soil or vegetation type, sometimes co-occur in the same habitat, and maintain their color traits in common-garden and soil switching experiments. Instead, we found strong associations between flower color and the composition of pollinator assemblages which are dominated by hopliine scarab beetles. Pollinator assemblages show geographical structuring, both within and among color forms. This makes it difficult to dissect the roles of geography versus floral traits in explaining pollinator assemblages, but strong pollinator partitioning among color forms at sites where they are sympatric indicates that pollinators may select strongly on color. These results suggest that beetle pollinators are a significant factor in the evolution of D. cistiflora s.l. flower color.
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Affiliation(s)
- Steven D. Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Caitlin G. von Witt
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Bruce Anderson
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
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12
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Geerts S, Coetzee A, Rebelo AG, Pauw A. Pollination structures plant and nectar‐feeding bird communities in Cape fynbos, South Africa: Implications for the conservation of plant–bird mutualisms. Ecol Res 2020. [DOI: 10.1111/1440-1703.12148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sjirk Geerts
- Department Conservation and Marine Sciences Cape Peninsula University of Technology Cape Town South Africa
| | - Anina Coetzee
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology University of Cape Town Cape Town South Africa
| | - Anthony G. Rebelo
- South African National Biodiversity Institute, Kirstenbosch Research Centre Claremont South Africa
| | - Anton Pauw
- Department of Botany and Zoology Stellenbosch University Matieland South Africa
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Le Maitre NC, Pirie MD, Bellstedt DU. Floral Color, Anthocyanin Synthesis Gene Expression and Control in Cape Erica Species. FRONTIERS IN PLANT SCIENCE 2019; 10:1565. [PMID: 31850039 PMCID: PMC6892755 DOI: 10.3389/fpls.2019.01565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/07/2019] [Indexed: 05/31/2023]
Abstract
Introduction: The Cape Floristic Region (CFR) is a biodiversity hotspot, recognized globally for its unusually high levels of endemism. The origins of this biodiversity are a long-standing topic of research. The largest "Cape clade," Erica, radiated dramatically in the CFR, its ca. 690 species arising within 10-15 Ma. Notable between- and within-species flower color variation in Erica may have contributed to the origins of species diversity through its impact on pollinator efficiency and specificity. Methods: We investigate the expression and function of the genes of the anthocyanin biosynthesis pathway that controls floral color in 12 Erica species groups using RT-qPCR and UPLC-MS/MS. Results: Shifts from ancestral pink- or red- to white- and/or yellow flowers were associated with independent losses of single pathway gene expression, abrogation of the entire pathway due to loss of the expression of a transcription factor or loss of function mutations in pathway genes. Discussion: Striking floral color shifts are prevalent amongst the numerous species of Cape Erica. These results show independent origins of a palette of mutations leading to such shifts, revealing the diverse genetic basis for potentially rapid evolution of a speciation-relevant trait.
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Affiliation(s)
- N C Le Maitre
- Bellstedt Laboratory, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Michael David Pirie
- Johannes Gutenberg-Universität, Mainz, Mainz, Germany
- University Museum, University of Bergen, Bergen, Norway
| | - Dirk U. Bellstedt
- Bellstedt Laboratory, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
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14
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Del Valle JC, Alcalde-Eon C, Escribano-Bailón MT, Buide ML, Whittall JB, Narbona E. Stability of petal color polymorphism: the significance of anthocyanin accumulation in photosynthetic tissues. BMC PLANT BIOLOGY 2019; 19:496. [PMID: 31726989 PMCID: PMC6854811 DOI: 10.1186/s12870-019-2082-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/17/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Anthocyanins are the primary source of colour in flowers and also accumulate in vegetative tissues, where they have multiple protective roles traditionally attributed to early compounds of the metabolic pathway (flavonols, flavones, etc.). Petal-specific loss of anthocyanins in petals allows plants to escape from the negative pleiotropic effects of flavonoid and anthocyanins loss in vegetative organs, where they perform a plethora of essential functions. Herein, we investigate the degree of pleiotropy at the biochemical scale in a pink-white flower colour polymorphism in the shore campion, Silene littorea. We report the frequencies of pink and white individuals across 21 populations and underlying biochemical profiles of three flower colour variants: anthocyanins present in all tissues (pink petals), petal-specific loss of anthocyanins (white petals), and loss of anthocyanins in all tissues (white petals). RESULTS Individuals lacking anthocyanins only in petals represent a stable polymorphism in two populations at the northern edge of the species range (mean frequency 8-21%). Whereas, individuals lacking anthocyanins in the whole plant were found across the species range, yet always at very low frequencies (< 1%). Biochemically, the flavonoids detected were anthocyanins and flavones; in pigmented individuals, concentrations of flavones were 14-56× higher than anthocyanins across tissues with differences of > 100× detected in leaves. Loss of anthocyanin pigmentation, either in petals or in the whole plant, does not influence the ability of these phenotypes to synthesize flavones, and this pattern was congruent among all sampled populations. CONCLUSIONS We found that all colour variants showed similar flavone profiles, either in petals or in the whole plant, and only the flower colour variant with anthocyanins in photosynthetic tissues persists as a stable flower colour polymorphism. These findings suggest that anthocyanins in photosynthetic tissues, not flavonoid intermediates, are the targets of non-pollinator mediated selection.
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Affiliation(s)
- José Carlos Del Valle
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, 41013, Seville, Spain.
| | - Cristina Alcalde-Eon
- Grupo de Investigación en Polifenoles (GIP), University of Salamanca, 37007, Salamanca, Spain
| | | | - Mª Luisa Buide
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, 41013, Seville, Spain
| | - Justen B Whittall
- Department of Biology, Santa Clara University, Santa Clara, CA, 95053, USA
| | - Eduardo Narbona
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, 41013, Seville, Spain
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15
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Le Maitre NC, Pirie MD, Bellstedt DU. An approach to determining anthocyanin synthesis enzyme gene expression in an evolutionary context: an example from Erica plukenetii. ANNALS OF BOTANY 2019; 124:121-130. [PMID: 31008513 PMCID: PMC6676384 DOI: 10.1093/aob/mcz046] [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: 05/14/2018] [Accepted: 03/24/2019] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Floral colour in angiosperms can be controlled by variations in the expression of the genes of the anthocyanin pathway. Floral colour shifts influence pollinator specificity. Multiple shifts in floral colour occurred in the diversification of the genus Erica (Ericaceae), from plesiomorphic pink to, for example, red or white flowers. Variation in anthocyanin gene expression and its effects on floral colour in the red-, pink- and white-flowered Erica plukenetii species complex was investigated. METHODS Next generation sequencing, reverse transcriptase PCR and real-time reverse transcriptase quantitative PCR were used to quantify anthocyanin gene expression. KEY RESULTS Non-homologous mutations causing loss of expression of single genes were found, indicating that the cause was likely to be mutations in transcription factor binding sites upstream of the 5'-untranslated region of the genes, and this was confirmed by sequencing. CONCLUSIONS Independent evolution and subsequent loss of expression of anthocyanin genes may have influenced diversification in the E. plukenetii species complex. The approach developed here should find more general application in studies on the role of floral colour shifts in diversification.
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Affiliation(s)
- N C Le Maitre
- Biochemistry Department, Stellenbosch University, Private Bag X1, Matieland, South Africa
- University of the Free State, Bloemfontein, South Africa
| | - M D Pirie
- Johannes Gutenberg-Universität, Mainz, Mainz, Germany
- University Museum, University of Bergen, Postboks, Bergen, Norway
| | - D U Bellstedt
- Biochemistry Department, Stellenbosch University, Private Bag X1, Matieland, South Africa
- For correspondence. E-mail
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Ojeda F, Midgley J, Pauw A, Lavola A, Casimiro-Soriguer R, Hattas D, Segarra-Moragues JG, Julkunen-Tiitto R. Flower colour divergence is associated with post-fire regeneration dimorphism in the fynbos heath Erica coccinea subsp. coccinea (Ericaceae). Evol Ecol 2019. [DOI: 10.1007/s10682-019-09985-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Vaidya P, McDurmon A, Mattoon E, Keefe M, Carley L, Lee CR, Bingham R, Anderson JT. Ecological causes and consequences of flower color polymorphism in a self-pollinating plant (Boechera stricta). THE NEW PHYTOLOGIST 2018; 218:380-392. [PMID: 29369384 DOI: 10.1111/nph.14998] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/12/2017] [Indexed: 05/21/2023]
Abstract
Intraspecific variation in flower color is often attributed to pollinator-mediated selection, yet this mechanism cannot explain flower color polymorphisms in self-pollinating species. Indirect selection mediated via biotic and abiotic stresses could maintain flower color variation in these systems. The selfing forb, Boechera stricta, typically displays white flowers, but some individuals produce purple flowers. We quantified environmental correlates of flower color in natural populations. To disentangle plasticity from genotypic variation, we performed a multiyear field experiment in five gardens. In controlled conditions, we evaluated herbivore preferences and the effects of drought stress and soil pH on flower color expression. In natural populations, purple-flowered individuals experienced lower foliar herbivory than did their white-flowered counterparts. This pattern also held in the common gardens. Additionally, low-elevation environments induced pigmented flowers (plasticity), and the likelihood of floral pigmentation decreased with source elevation of maternal families (genetic cline). Viability selection favored families with pigmented flowers. In the laboratory, herbivores exerted greater damage on tissue derived from white- vs purple-flowered individuals. Furthermore, drought induced pigmentation in white-flowered lineages, and white-flowered plants had a fecundity advantage in the well-watered control. Flower color variation in selfing species is probably maintained by herbivory, drought stress, and other abiotic factors that vary spatially.
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Affiliation(s)
- Priya Vaidya
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Ansley McDurmon
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
| | - Emily Mattoon
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Michaela Keefe
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
- Department of Natural and Environmental Sciences, Western State Colorado University, Gunnison, CO, 81231, USA
| | - Lauren Carley
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
- Department of Biology, Duke University, Durham, NC, 27708, USA
- University Program in Ecology, Duke University, Durham, NC, 27708, USA
| | - Cheng-Ruei Lee
- Institute of Ecology and Evolutionary Biology & Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Robin Bingham
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
- Department of Natural and Environmental Sciences, Western State Colorado University, Gunnison, CO, 81231, USA
| | - Jill T Anderson
- The Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
- Department of Genetics and Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
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Varga S, Soulsbury CD. Sexually-trimorphic interactions with colour polymorphism determine nectar quality in a herbaceous perennial. Sci Rep 2017; 7:45838. [PMID: 28374829 PMCID: PMC5379179 DOI: 10.1038/srep45838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 03/06/2017] [Indexed: 11/09/2022] Open
Abstract
Amongst gynodioecious plant breeding systems, there can exist intermediate morphs with a reduction in their male function (i.e. reduced number of functional anthers). Along with this sexual trimorphism, plants can also show floral colour polymorphism. Such intricate mixtures of phenotypes within a species may have complex effects on floral rewards. Floral rewards are known to vary between sexually dimorphic species and to a lesser extent between colour morphs. However, the interactive effect of sexual trimorphism and colour polymorphism is unexplored. We measured nectar's sugar content in the sexually trimorphic Geranium sylvaticum, a gynodioecious plant with a light/dark floral polymorphism. We found that nectar reward differed across genders and colour morphs. Results were not however consistent within the three genders; dark female and hermaphrodite flowers had higher sugar content than light morphs, whereas intermediate flowers did not. As expected, females and hermaphrodites had different nectar reward, with intermediate morphs being midway between the other genders. In intermediates, the sugar content was not related to the number of functional stamens. We show for the first time the existence of sex-specific differences between flower gender and colour morphs in nectar rewards. Our results demonstrate the importance of considering multiple and conflicting selection pressures to explain rewards.
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Affiliation(s)
- Sandra Varga
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Lincoln LN6 7TS, UK
| | - Carl D. Soulsbury
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Lincoln LN6 7TS, UK
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Sun SG, Armbruster WS, Huang SQ. Geographic consistency and variation in conflicting selection generated by pollinators and seed predators. ANNALS OF BOTANY 2016; 118:227-37. [PMID: 27325896 PMCID: PMC4970362 DOI: 10.1093/aob/mcw097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/05/2016] [Indexed: 05/13/2023]
Abstract
BACKGROUNDS AND AIMS Floral traits that attract pollinators may also attract seed predators, which, in turn, may generate conflicting natural selection on such traits. Although such selection trade-offs are expected to vary geographically, few studies have investigated selection mediated by pollinators and seed predators across a geographic mosaic of environments and floral variation. METHODS Floral traits were investigated in 14 populations of the bumble-bee-pollinated herb, Pedicularis rex, in which tubular flowers are subtended by cupular bracts holding rain water. To study potentially conflicting selection on floral traits generated by pollinators and florivores, stigmatic pollen loads, initial seed set, pre-dispersal seed predation and final viable seed production were measured in 12-14 populations in the field. KEY RESULTS Generalized Linear Model (GLM) analyses indicated that the pollen load on stigmas was positively related to the exsertion of the corolla beyond the cupular bracts and size of the lower corolla lip, but so too was the rate of seed predation, creating conflicting selection on both floral traits. A geographic mosaic of selection mediated by seed predators, but not pollinators, was indicated by significant variation in levels of seed predation and the inclusion of two-, three- and four-way interaction terms between population and seed predation in the best model [lowest corrected Akaike Information Criterion (AICc)] explaining final seed production. CONCLUSIONS These results indicate opposing selection in operation: pollinators generated selection for greater floral exsertion beyond the bracts, but seed predators generated selection for reduced exsertion above the protective pools of water, although the strength of the latter varied across populations.
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Affiliation(s)
- Shi-Guo Sun
- School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK Institute of Arctic Biology, University of Alaska, Fairbanks AK 99775-7000, USA
| | - Shuang-Quan Huang
- School of Life Sciences, Central China Normal University, Wuhan 430079, China
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Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations. PLoS One 2015; 10:e0132522. [PMID: 26172378 PMCID: PMC4501686 DOI: 10.1371/journal.pone.0132522] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 06/15/2015] [Indexed: 11/19/2022] Open
Abstract
Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.
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22
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Carlson JE, Holsinger KE. Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea. Proc Biol Sci 2015; 282:20150583. [PMID: 25876847 PMCID: PMC4426637 DOI: 10.1098/rspb.2015.0583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 03/20/2015] [Indexed: 11/12/2022] Open
Abstract
Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea-within which more than 40% of species have co-occurring pink and white floral colour morphs-to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales.
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Affiliation(s)
- Jane E Carlson
- Department of Ecology and Evolutionary Biology, University of Connecticut, U-3043, Storrs, CT 06269, USA
| | - Kent E Holsinger
- Department of Ecology and Evolutionary Biology, University of Connecticut, U-3043, Storrs, CT 06269, USA
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23
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Heystek A, Geerts S, Barnard P, Pauw A. Pink flower preference in sunbirds does not translate into plant fitness differences in a polymorphic Erica species. Evol Ecol 2014. [DOI: 10.1007/s10682-014-9693-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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