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Romero-Bravo A, Castellanos MC. Nectar and floral morphology differ in evolutionary potential in novel pollination environments. THE NEW PHYTOLOGIST 2024; 243:753-764. [PMID: 38714871 DOI: 10.1111/nph.19780] [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: 02/13/2024] [Accepted: 03/25/2024] [Indexed: 06/21/2024]
Abstract
Plants can evolve rapidly after pollinator changes, but the response of different floral traits to novel selection can vary. Floral morphology is often expected to show high integration to maintain pollination accuracy, while nectar traits can be more environmentally sensitive. The relative role of genetic correlations and phenotypic plasticity (PP) in floral evolution remains unclear, particularly for nectar traits, and can be studied in the context of recent pollinator changes. Digitalis purpurea shows rapid recent evolution of corolla morphology but not nectar traits following a range expansion with hummingbirds added as pollinators. We use this species to compare PP, heritability, evolvability and integration of floral morphology and nectar in a common garden. Morphological traits showed higher heritability than nectar traits, and the proximal section of the corolla, which regulates access to nectar and underwent rapid change in introduced populations, presented lower integration than the rest of the floral phenotype. Nectar was more plastic than morphology, driven by highly plastic sugar concentration. Nectar production rate showed high potential to respond to selection. These results explain the differential rapid evolution of floral traits previously observed in this species and show how intrafloral modularity determines variable evolutionary potential in morphological and nectar traits.
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Affiliation(s)
- Andrés Romero-Bravo
- Department of Ecology & Evolution, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Maria Clara Castellanos
- Department of Ecology & Evolution, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
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2
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Wessinger CA. How the switch to hummingbird pollination has greatly contributed to our understanding of evolutionary processes. THE NEW PHYTOLOGIST 2024; 241:59-64. [PMID: 37853523 PMCID: PMC10843001 DOI: 10.1111/nph.19335] [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: 08/04/2023] [Accepted: 09/30/2023] [Indexed: 10/20/2023]
Abstract
The evolutionary switch to hummingbird pollination exemplifies complex adaptation, requiring evolutionary change in multiple component traits. Despite this complexity, diverse lineages have converged on hummingbird-adapted flowers on a relatively short evolutionary timescale. Here, I review how features of the genetic basis of adaptation contribute to this remarkable evolutionary lability. Large-effect substitutions, large mutational targets for adaptation, adaptive introgression, and concentrated architecture all contribute to the origin and maintenance of hummingbird-adapted flowers. The genetic features of adaptation are likely shaped by the ecological and geographic context of the switch to hummingbird pollination, with implications for future evolutionary trajectories.
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Affiliation(s)
- Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA
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Poulin V, Amesefe D, Gonzalez E, Alexandre H, Joly S. Testing candidate genes linked to corolla shape variation of a pollinator shift in Rhytidophyllum (Gesneriaceae). PLoS One 2022; 17:e0267540. [PMID: 35853078 PMCID: PMC9295946 DOI: 10.1371/journal.pone.0267540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/12/2022] [Indexed: 11/18/2022] Open
Abstract
Floral adaptations to specific pollinators like corolla shape variation often result in reproductive isolation and thus speciation. But despite their ecological importance, the genetic bases of corolla shape transitions are still poorly understood, especially outside model species. Hence, our goal was to identify candidate genes potentially involved in corolla shape variation between two closely related species of the Rhytidophyllum genus (Gesneriaceae family) from the Antilles with contrasting pollination strategies. Rhytidophyllum rupincola has a tubular corolla and is strictly pollinated by hummingbirds, whereas R. auriculatum has more open flowers and is pollinated by hummingbirds, bats, and insects. We surveyed the literature and used a comparative transcriptome sequence analysis of synonymous and non-synonymous nucleotide substitutions to obtain a list of genes that could explain floral variation between R. auriculatum and R. rupincola. We then tested their association with corolla shape variation using QTL mapping in a F2 hybrid population. Out of 28 genes tested, three were found to be good candidates because of a strong association with corolla shape: RADIALIS, GLOBOSA, and JAGGED. Although the role of these genes in Rhytidophyllum corolla shape variation remains to be confirmed, these findings are a first step towards identifying the genes that have been under selection by pollinators and thus involved in reproductive isolation and speciation in this genus.
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Affiliation(s)
- Valérie Poulin
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Canada
| | - Delase Amesefe
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Canada
| | - Emmanuel Gonzalez
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Canada
- Department of Human Genetics, Canadian Centre for Computational Genomics (C3G), McGill University, Montréal, QC, Canada
- Microbiome Research Platform, McGill Interdisciplinary Initiative in Infection and Immunity (MI4), Genome Centre, McGill University, Montréal, QC, Canada
| | - Hermine Alexandre
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Canada
| | - Simon Joly
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Canada
- Montreal Botanical Garden, Montréal, Canada
- * E-mail:
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Myers BM, Rankin DT, Burns KJ, Brelsford A, Clark CJ. k-mer analysis shows hybrid hummingbirds perform variable, transgressive courtship sequences. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Boehm MMA, Jankowski JE, Cronk QCB. Plant-Pollinator Specialization: Origin and Measurement of Curvature. Am Nat 2021; 199:206-222. [DOI: 10.1086/717677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Mannfred M. A. Boehm
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jill E. Jankowski
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, 4200-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
| | - Quentin C. B. Cronk
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
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Kay KM, Surget-Groba Y. The genetic basis of floral mechanical isolation between two hummingbird-pollinated Neotropical understorey herbs. Mol Ecol 2021; 31:4351-4363. [PMID: 34487383 DOI: 10.1111/mec.16165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/29/2021] [Accepted: 08/31/2021] [Indexed: 12/29/2022]
Abstract
Floral divergence can contribute to reproductive isolation among plant lineages, and thus provides an opportunity to study the genetics of speciation, including the number, effect size, mode of action and interactions of quantitative trait loci (QTL). Moreover, flowers represent suites of functionally interrelated traits, but it is unclear to what extent the phenotypic integration of the flower is underlain by a shared genetic architecture, which could facilitate or constrain correlated evolution of floral traits. Here, we examine the genetic architecture of floral morphological traits involved in an evolutionary switch from bill to forehead pollen placement between two species of hummingbird-pollinated Neotropical understorey herbs that are reproductively isolated by these floral differences. For the majority of traits, we find multiple QTL of relatively small effect spread throughout the genome. We also find substantial colocalization and alignment of effects of QTL underlying different floral traits that function together to promote outcrossing and reduce heterospecific pollen transfer. Our results are consistent with adaptive pleiotropy or linkage of many co-adapted genes, either of which could have facilitated a response to correlated selection and helped to stabilize divergent phenotypes in the face of low levels of hybridization. Moreover, our results indicate that floral mechanical isolation can be consistent with an infinitesimal model of adaptation.
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Affiliation(s)
- Kathleen M Kay
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Yann Surget-Groba
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA.,Département de Biologie, Université du Québec en Outaouais, Ripon, QC, Canada
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7
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Kriebel R, Drew B, González-Gallegos JG, Celep F, Heeg L, Mahdjoub MM, Sytsma KJ. Pollinator shifts, contingent evolution, and evolutionary constraint drive floral disparity in Salvia (Lamiaceae): Evidence from morphometrics and phylogenetic comparative methods. Evolution 2020; 74:1335-1355. [PMID: 32484910 DOI: 10.1111/evo.14030] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/21/2020] [Indexed: 12/23/2022]
Abstract
Switches in pollinators have been argued to be key drivers of floral evolution in angiosperms. However, few studies have tested the relationship between floral shape evolution and switches in pollination in large clades. In concert with a dated phylogeny, we present a morphometric analysis of corolla, anther connective, and style shape across 44% of nearly 1000 species of Salvia (Lamiaceae) and test four hypotheses of floral evolution. We demonstrate that floral morphospace of New World (NW) Salvia is largely distinct from that of Old World (OW) Salvia and that these differences are pollinator driven; shifts in floral morphology sometimes mirror shifts in pollinators; anther connectives (key constituents of the Salvia staminal lever) and styles co-evolved from curved to linear shapes following shifts from bee to bird pollination; and morphological differences between NW and OW bee flowers are partly the legacy of constraints imposed by an earlier shift to bird pollination in the NW. The distinctive staminal lever in Salvia is a morphologically diverse structure that has evolved in concert with both the corolla and style, under different pollinator pressures, and in contingent fashion.
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Affiliation(s)
- Ricardo Kriebel
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Bryan Drew
- Department of Biology, University of Nebraska at Kearney, Kearney, Nebraska, 68849
| | | | - Ferhat Celep
- Department of Biology, Faculty of Arts and Sciences, Kırıkkale University, Yahşiyan, 71450, Turkey
| | - Luciann Heeg
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Mohamed M Mahdjoub
- Department of Biology, Faculty of Natural and Life Sciences and Earth Sciences, University of Bouira, Bouira, 10000, Algeria
| | - Kenneth J Sytsma
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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Roberts WR, Roalson EH. Co-expression clustering across flower development identifies modules for diverse floral forms in Achimenes (Gesneriaceae). PeerJ 2020; 8:e8778. [PMID: 32201652 PMCID: PMC7071821 DOI: 10.7717/peerj.8778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/21/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Genetic pathways involved with flower color and shape are thought to play an important role in the development of flowers associated with different pollination syndromes, such as those associated with bee, butterfly, or hummingbird pollination. Because pollination syndromes are complex traits that are orchestrated by multiple genes and pathways, the gene regulatory networks have not been explored. Gene co-expression networks provide a systems level approach to identify important contributors to floral diversification. METHODS RNA-sequencing was used to assay gene expression across two stages of flower development (an early bud and an intermediate stage) in 10 species of Achimenes (Gesneriaceae). Two stage-specific co-expression networks were created from 9,503 orthologs and analyzed to identify module hubs and the network periphery. Module association with bee, butterfly, and hummingbird pollination syndromes was tested using phylogenetic mixed models. The relationship between network connectivity and evolutionary rates (d N/d S) was tested using linear models. RESULTS Networks contained 65 and 62 modules that were largely preserved between developmental stages and contained few stage-specific modules. Over a third of the modules in both networks were associated with flower color, shape, and pollination syndrome. Within these modules, several hub nodes were identified that related to the production of anthocyanin and carotenoid pigments and the development of flower shape. Evolutionary rates were decreased in highly connected genes and elevated in peripheral genes. DISCUSSION This study aids in the understanding of the genetic architecture and network properties underlying the development of floral form and provides valuable candidate modules and genes for future studies.
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Affiliation(s)
- Wade R. Roberts
- School of Biological Sciences, Washington State University, Pullman, WA, USA
- Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Eric H. Roalson
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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Joly S, Lambert F, Alexandre H, Clavel J, Léveillé‐Bourret É, Clark JL. Greater pollination generalization is not associated with reduced constraints on corolla shape in Antillean plants. Evolution 2018; 72:244-260. [DOI: 10.1111/evo.13410] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 11/29/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Simon Joly
- Montreal Botanical Garden 4101 Sherbrooke East Montréal QC, H1X 2B2 Canada
- Institut de recherche en biologie végétale, Département de sciences biologiquesUniversité de MontréalMontréal Canada
| | - François Lambert
- Institut de recherche en biologie végétale, Département de sciences biologiquesUniversité de MontréalMontréal Canada
| | - Hermine Alexandre
- Institut de recherche en biologie végétale, Département de sciences biologiquesUniversité de MontréalMontréal Canada
| | - Julien Clavel
- École Normale Supérieure, Paris Sciences et Lettres (PSL) Research University, Institut de Biologie de l'École Normale Supérieure (IBENS), CNRS UMR 8197, INSERM U1024, 46 rue d'Ulm F‐75005 Paris France
| | - Étienne Léveillé‐Bourret
- Institut de recherche en biologie végétale, Département de sciences biologiquesUniversité de MontréalMontréal Canada
- Current Address: Department of BiologyUniversity of OttawaOttawa Canada
| | - John L. Clark
- Department of Biological SciencesThe University of AlabamaTuscaloosa, Alabama 35487
- Science DepartmentThe Lawrenceville SchoolLawrenceville, New Jersey U.S.A
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10
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Lagomarsino LP, Forrestel EJ, Muchhala N, Davis CC. Repeated evolution of vertebrate pollination syndromes in a recently diverged Andean plant clade. Evolution 2017. [DOI: 10.1111/evo.13297] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Laura P. Lagomarsino
- Department of Organismic and Evolutionary Biology Harvard University Herbaria 22 Divinity Avenue Cambridge Massachusetts 02138
- Current Address: Department of Biology University of Missouri–St. Louis, and Missouri Botanical Garden 4500 Shaw Boulevard St. Louis Missouri 63110
| | | | - Nathan Muchhala
- Department of Biology, University of Missouri–St. Louis, Research Building One University Boulevard St. Louis Missouri 63121
| | - Charles C. Davis
- Department of Organismic and Evolutionary Biology Harvard University Herbaria 22 Divinity Avenue Cambridge Massachusetts 02138
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11
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Hsu HC, Wang CN, Liang CH, Wang CC, Kuo YF. Association between Petal Form Variation and CYC2-like Genotype in a Hybrid Line of Sinningia speciosa. FRONTIERS IN PLANT SCIENCE 2017; 8:558. [PMID: 28458679 PMCID: PMC5394160 DOI: 10.3389/fpls.2017.00558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/28/2017] [Indexed: 05/20/2023]
Abstract
This study used three-dimensional (3D) micro-computed tomography (μCT) imaging to examine petal form variation in a hybrid cross of Sinningia speciosa between a cultivar with actinomorphic flowers and a variety with zygomorphic flowers. The major objectives were to determine the genotype-phenotype associations between the petal form variation and CYCLOIDEA2-like alleles in S. speciosa (SsCYC) and to morphologically investigate the differences in petal types between actinomorphic and zygomorphic flowers. In this study, μCT was used to accurately acquire 3D floral images. Landmark-based geometric morphometrics (GM) was applied to evaluate the major form variations of the petals. Nine morphological traits of the petals were defined according to the form variations quantified through the GM analysis. The results indicated that the outward curvature of dorsal petals, the midrib asymmetry of lateral petals, and the dilation of ventral region of the tube were closely associated with the SsCYC genotype. Multiple analyses of form similarity between the petals suggested that the dorsal and ventral petals of actinomorphic plants resembled the ventral petals of zygomorphic plants. This observation indicated that the transition from zygomorphic to actinomorphic flowers in S. speciosa might be caused by the ventralization of the dorsal petals. We demonstrated that the 3D-GM approach can be used to determine genotype-phenotype associations and to provide morphological evidence for the transition of petal types between actinomorphic and zygomorphic flowers in S. speciosa.
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Affiliation(s)
- Hao-Chun Hsu
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan UniversityTaipei, Taiwan
| | - Chun-Neng Wang
- Institute of Ecology and Evolutionary Biology, National Taiwan UniversityTaipei, Taiwan
- Department of Life Science, National Taiwan UniversityTaipei, Taiwan
| | - Chia-Hao Liang
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan UniversityTaipei, Taiwan
| | - Cheng-Chun Wang
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan UniversityTaipei, Taiwan
| | - Yan-Fu Kuo
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan UniversityTaipei, Taiwan
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12
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Roberts WR, Roalson EH. Comparative transcriptome analyses of flower development in four species of Achimenes (Gesneriaceae). BMC Genomics 2017; 18:240. [PMID: 28320315 PMCID: PMC5359931 DOI: 10.1186/s12864-017-3623-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 03/11/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Flowers have an amazingly diverse display of colors and shapes, and these characteristics often vary significantly among closely related species. The evolution of diverse floral form can be thought of as an adaptive response to pollination and reproduction, but it can also be seen through the lens of morphological and developmental constraints. To explore these interactions, we use RNA-seq across species and development to investigate gene expression and sequence evolution as they relate to the evolution of the diverse flowers in a group of Neotropical plants native to Mexico-magic flowers (Achimenes, Gesneriaceae). RESULTS The assembled transcriptomes contain between 29,000 and 42,000 genes expressed during development. We combine sequence orthology and coexpression clustering with analyses of protein evolution to identify candidate genes for roles in floral form evolution. Over 25% of transcripts captured were distinctive to Achimenes and overrepresented by genes involved in transcription factor activity. Using a model-based clustering approach we find dynamic, temporal patterns of gene expression among species. Selection tests provide evidence of positive selection in several genes with roles in pigment production, flowering time, and morphology. Combining these approaches to explore genes related to flower color and flower shape, we find distinct patterns that correspond to transitions of floral form among Achimenes species. CONCLUSIONS The floral transcriptomes developed from four species of Achimenes provide insight into the mechanisms involved in the evolution of diverse floral form among closely related species with different pollinators. We identified several candidate genes that will serve as an important and useful resource for future research. High conservation of sequence structure, patterns of gene coexpression, and detection of positive selection acting on few genes suggests that large phenotypic differences in floral form may be caused by genetic differences in a small set of genes. Our characterized floral transcriptomes provided here should facilitate further analyses into the genomics of flower development and the mechanisms underlying the evolution of diverse flowers in Achimenes and other Neotropical Gesneriaceae.
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Affiliation(s)
- Wade R. Roberts
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, WA 99164-1030 USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236 USA
| | - Eric H. Roalson
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, WA 99164-1030 USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236 USA
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