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Dixit NM, Guicking D. Exploring the evolutionary dynamics of myrmecophytism: Perspectives from the Southeast Asian Macaranga ant-plant symbiosis. Mol Phylogenet Evol 2024; 194:108028. [PMID: 38342161 DOI: 10.1016/j.ympev.2024.108028] [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: 11/08/2023] [Revised: 01/31/2024] [Accepted: 02/04/2024] [Indexed: 02/13/2024]
Abstract
Myrmecophytic plants utilise defensive services offered by obligate ant partners nesting in their domatia in a novel means of survival in tropical habitats. Although much is known about the ecology of myrmecophytism, there aren't enough empirical examples to demonstrate whether it substantially influences evolutionary patterns in host plant lineages. In this study, we make use of the species-rich Macaranga (Euphorbiaceae) ant-plant symbiosis distributed in the Southeast Asian Sundaland to delve into the evolutionary dynamics of myrmecophytism in host plants. We generated the most comprehensive dated phylogeny of myrmecophytic Macaranga till date using genotyping-by-sequencing (GBS). With this in hand, we traced the evolutionary history of myrmecophytism in Macaranga using parametric biogeography and ancestral state reconstruction. Diversification rate analysis methods were employed to determine if myrmecophytism enhanced diversification rates in the genus. Our results demonstrate that myrmecophytism is labile and easily lost. Ancestral state reconstruction supported a single origin of myrmecophytism in Macaranga ∼18 mya on Borneo followed by multiple losses. Diversification rate analysis methods did not yield sufficient evidence to support the hypothesis that myrmecophytism enhanced diversification rates in Macaranga; we found that topographical features on Borneo may have played a more direct role in the divergence of clades instead. Our study provides evidence that while the acquisition of domatia clearly functions as a key innovation that has enabled host plants to exploit the environment in novel ways, it may not necessarily enhance diversification rates. In fact, we hypothesise that overly specialised cases of myrmecophytism may even be an evolutionary dead end.
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Affiliation(s)
- Nadi M Dixit
- Department of Botany, Institute of Biology, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany.
| | - Daniela Guicking
- Department of Botany, Institute of Biology, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany.
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2
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Becker A, Bachelier JB, Carrive L, Conde E Silva N, Damerval C, Del Rio C, Deveaux Y, Di Stilio VS, Gong Y, Jabbour F, Kramer EM, Nadot S, Pabón-Mora N, Wang W. A cornucopia of diversity-Ranunculales as a model lineage. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1800-1822. [PMID: 38109712 DOI: 10.1093/jxb/erad492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023]
Abstract
The Ranunculales are a hyperdiverse lineage in many aspects of their phenotype, including growth habit, floral and leaf morphology, reproductive mode, and specialized metabolism. Many Ranunculales species, such as opium poppy and goldenseal, have a high medicinal value. In addition, the order includes a large number of commercially important ornamental plants, such as columbines and larkspurs. The phylogenetic position of the order with respect to monocots and core eudicots and the diversity within this lineage make the Ranunculales an excellent group for studying evolutionary processes by comparative studies. Lately, the phylogeny of Ranunculales was revised, and genetic and genomic resources were developed for many species, allowing comparative analyses at the molecular scale. Here, we review the literature on the resources for genetic manipulation and genome sequencing, the recent phylogeny reconstruction of this order, and its fossil record. Further, we explain their habitat range and delve into the diversity in their floral morphology, focusing on perianth organ identity, floral symmetry, occurrences of spurs and nectaries, sexual and pollination systems, and fruit and dehiscence types. The Ranunculales order offers a wealth of opportunities for scientific exploration across various disciplines and scales, to gain novel insights into plant biology for researchers and plant enthusiasts alike.
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Affiliation(s)
- Annette Becker
- Plant Development Group, Institute of Botany, Justus-Liebig-University, Giessen, Germany
| | - Julien B Bachelier
- Institute of Biology/Dahlem Centre of Plant Sciences, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Laetitia Carrive
- Université de Rennes, UMR CNRS 6553, Ecosystèmes-Biodiversité-Evolution, Campus de Beaulieu, 35042 Rennes cedex, France
| | - Natalia Conde E Silva
- Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Génétique Quantitative et Evolution-Le Moulon, 91190 Gif-sur-Yvette, France
| | - Catherine Damerval
- Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Génétique Quantitative et Evolution-Le Moulon, 91190 Gif-sur-Yvette, France
| | - Cédric Del Rio
- CR2P - Centre de Recherche en Paléontologie - Paris, MNHN - Sorbonne Université - CNRS, 43 Rue Buffon, 75005 Paris, France
| | - Yves Deveaux
- Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Génétique Quantitative et Evolution-Le Moulon, 91190 Gif-sur-Yvette, France
| | | | - Yan Gong
- Department of Organismic and Evolutionary Biology, Harvard University, MA, 02138, USA
| | - Florian Jabbour
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, 57 rue Cuvier, CP39, Paris, 75005, France
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, MA, 02138, USA
| | - Sophie Nadot
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie, Systématique et Evolution, Gif-sur-Yvette, France
| | - Natalia Pabón-Mora
- Instituto de Biología, Universidad de Antioquia, Medellín, 050010, Colombia
| | - Wei Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China and University of Chinese Academy of Sciences, Beijing, 100049China
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3
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Ronse De Craene LP. The interaction between heterochrony and mechanical forces as main driver of floral evolution. JOURNAL OF PLANT RESEARCH 2024:10.1007/s10265-024-01526-3. [PMID: 38407783 DOI: 10.1007/s10265-024-01526-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/21/2024] [Indexed: 02/27/2024]
Abstract
Heterochrony acts as a fundamental process affecting the early development of organisms in creating a subtle shift in the timing of initiation or the duration of a developmental process. In flowers this process is linked with mechanical forces that cause changes in the interaction of neighbouring floral organs by altering the timing and rate of initiation of organs. Heterochrony leads to a delay or acceleration of the development of neighbouring primordia, inducing a change in the morphospace of the flowers. As changes in the timing of development may affect organs differently at different stages of development, these shifts eventually lead to major morphological changes such as altered organ positions, fusions, or organ reductions with profound consequences for floral evolution and the diversification of flowers. By concentrating on early developmental stages in flowers it is possible to understand how heterochrony is responsible for shifts in organ position and the establishment of a novel floral Bauplan. However, it remains difficult to separate heterochrony as a process from pattern, as both are intimately linked. Therefore it is essential to connect different patterns in flowers through the process of developmental change.Examples illustrating the importance of heterochronic shifts affecting different organs of the flower are presented and discussed. These cover the transition from inflorescence to flower through the interaction of bracts and bracteoles, the pressure exercised by the perianth on the androecium and gynoecium, the inversed influence of stamens on petals, and the centrifugal influence of carpels on the androecium. Different processes are explored, including the occurrence of obdiplostemony, the onset of common primordia, variable carpel positions, and organ reduction and loss.
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4
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Strelin MM, Diggle PK, Aizen MA. Flower heterochrony and crop yield. TRENDS IN PLANT SCIENCE 2023; 28:1360-1369. [PMID: 37612211 DOI: 10.1016/j.tplants.2023.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 06/17/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023]
Abstract
Crop improvement has focused on enhancing yield, nutrient content, harvestability, and stress resistance using a trait-centered reductionist approach. This has downplayed the fact that plants are developmentally integrated and respond coordinately and predictably to genetic and environmental variation, with potential consequences for food production. Crop yield, including both fruit/seed production and the possibility of generating hybrid crop varieties, is highly dependent on flower morphology and sex, which, in turn, can be profoundly affected by slight shifts in the timing and rate of flower organ development (i.e., flower heterochrony). We argue that understanding the genetic and environmental bases of flower heterochrony and their effect on flower morphology and sex in cultivated plants and in their wild relatives can facilitate crop improvement.
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Affiliation(s)
- Marina M Strelin
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina.
| | - Pamela K Diggle
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Marcelo A Aizen
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina
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5
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Petrone-Mendoza E, Vergara-Silva F, Olson ME. Plant morpho evo-devo. TRENDS IN PLANT SCIENCE 2023; 28:1257-1276. [PMID: 37423784 DOI: 10.1016/j.tplants.2023.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023]
Abstract
Evo-devo is often thought of as being the study of which genes underlie which phenotypes. However, evo-devo is much more than this, especially in plant science. In leaf scars along stems, cell changes across wood growth rings, or flowers along inflorescences, plants trace a record of their own development. Plant morpho evo-devo provides data that genes could never furnish on themes such as heterochrony, the evolution of temporal phenotypes, modularity, and phenotype-first evolution. As plant science surges into increasingly -omic realms, it is essential to keep plant morpho evo-devo in full view as an honored member of the evo-devo canon, ensuring that plant scientists can, wherever they are, generate fundamental insights at the appropriate level of biological organization.
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Affiliation(s)
- Emilio Petrone-Mendoza
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México 04510, México; Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, C.P. 04510, CDMX, México
| | - Francisco Vergara-Silva
- Laboratorio de Teoría Evolutiva e Historia de la Ciencia, Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México 04510, México.
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6
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Cullen E, Wang Q, Glover BJ. How do you build a nectar spur? A transcriptomic comparison of nectar spur development in Linaria vulgaris and gibba development in Antirrhinum majus. FRONTIERS IN PLANT SCIENCE 2023; 14:1190373. [PMID: 37426957 PMCID: PMC10328749 DOI: 10.3389/fpls.2023.1190373] [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: 03/20/2023] [Accepted: 05/23/2023] [Indexed: 07/11/2023]
Abstract
Nectar spurs (tubular outgrowths of floral organs) have long fascinated biologists. However, given that no model species possess nectar spurs, there is still much to learn about their development. In this study we combined morphological analysis with comparative transcriptomics to gain a global insight into the morphological and molecular basis of spur outgrowth in Linaria. Whole transcriptome sequencing was performed on two related species at three key developmental stages (identified by our morphological analysis), one with a spur (Linaria vulgaris), and one without a spur (Antirrhinum majus). A list of spur-specific genes was selected, on which we performed a gene enrichment analysis. Results from our RNA-seq analysis agreed with our morphological observations. We describe gene activity during spur development and provide a catalogue of spur-specific genes. Our list of spur-specific genes was enriched for genes connected to the plant hormones cytokinin, auxin and gibberellin. We present a global view of the genes involved in spur development in L. vulgaris, and define a suite of genes which are specific to spur development. This work provides candidate genes for spur outgrowth and development in L. vulgaris which can be investigated in future studies.
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Affiliation(s)
- Erin Cullen
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Qi Wang
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Beverley J. Glover
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
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7
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Li Y, Wei CM, Li XY, Meng DC, Gu ZJ, Qu SP, Huang MJ, Huang HQ. De novo transcriptome sequencing of Impatiens uliginosa and the analysis of candidate genes related to spur development. BMC PLANT BIOLOGY 2022; 22:553. [PMID: 36456926 PMCID: PMC9713998 DOI: 10.1186/s12870-022-03894-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/20/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Spur, a structure capable of producing and storing nectar, not only plays a vital role in the pollination process but also promotes the rapid diversification of some plant lineages, which is considered a key innovation in plants. Spur is the focus of many studies, such as evolution and ecological hypothesis, but the current understanding of spur development is limited. High-throughput sequencing of Impatiens uliginosa was carried out to study the molecular mechanism of its spur development, which is believed to provide some insights into the spur development of Impatiens. RESULTS Transcriptomic sequencing and analysis were performed on spurs and limbs of I. uliginosa at three developmental stages. A total of 47.83 Gb of clean data were obtained, and 49,716 unigene genes were assembled. After comparison with NR, Swiss-Prot, Pfam, COG, GO and KEGG databases, a total of 27,686 genes were annotated successfully. Through comparative analysis, 19,356 differentially expressed genes were found and enriched into 208 GO terms and 146 KEGG pathways, among which plant hormone signal transduction was the most significantly enriched pathway. One thousand thirty-two transcription factors were identified, which belonged to 33 TF families such as MYB, bHLH and TCP. Twenty candidate genes that may be involved in spur development were screened and verified by qPCR, such as SBP, IAA and ABP. CONCLUSIONS Transcriptome data of different developmental stages of spurs were obtained, and a series of candidate genes related to spur development were identified. The importance of genes related to cell cycle, cell division, cell elongation and hormones in spur development was clarified. This study provided valuable information and resources for understanding the molecular mechanism of spur development in Impatiens.
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Affiliation(s)
- Yang Li
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
| | - Chun-Mei Wei
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
| | - Xin-Yi Li
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
| | - Dan-Chen Meng
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
| | - Zhi-Jia Gu
- Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201 Yunnan China
| | - Su-Ping Qu
- Flower Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205 Yunnan China
| | - Mei-Juan Huang
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
| | - Hai-Quan Huang
- College of Landscape Architecture and Horticulture Sciences, Southwest Research Center for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Yunnan Engineering Research Center for Functional Flower Resources and Industrialization, Research and Development Center of Landscape Plants and Horticulture Flowers, Southwest Forestry University, Kunming, 650224 Yunnan China
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8
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Huang Z, Zhang X. Floral nectaries and pseudonectaries in Eranthis (Ranunculaceae): petal development, micromorphology, structure and ultrastructure. PROTOPLASMA 2022; 259:1283-1300. [PMID: 35066725 DOI: 10.1007/s00709-022-01738-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Flowers are an innovative characteristic of angiosperms, and elaborate petals usually have highly specialized structures to adapt to different living environments and pollinators. Petals of Eranthis have complex bilabiate structures with nectaries and pseudonectaries; however, the diversity of the petal micromorphology and structure is unknown. Petal development, micromorphology, structure and ultrastructure in four Eranthis species were investigated under SEM, TEM and LM. The results show that petals undergo 5 developmental stages, and accessory structure formation (stage 4) mainly determines the diversity of final mature petal morphology and pseudonectaries; the central depression formed in stage 2 will develop into nectary tissues. Petals are bilabiate and have hidden nectaries in nectary grooves; they consist of one layer of rounded and raised secretory epidermal cells and 3-14 layers of secretory cells with abundant plasmodesmata between cells. A large number of sieve tubes are distributed between the cells and extend to the epidermis; in addition, the vessel elements are located below the secretory area. Nectar is stored in the intercellular space between secretory parenchyma cells and escapes through microchannels or cell rupture. Pseudonectaries in all species of Eranthis except for E. hyemalis consist of smooth, ornamented epidermal cells and 9-12 layers of parenchyma cells with sparse cytoplasm, which may have the function of attracting pollinators.
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Affiliation(s)
- Zixuan Huang
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, People's Republic of China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Science, Shaanxi Normal University, Xi'an, 710062, People's Republic of China
| | - Xiaohui Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, People's Republic of China.
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Science, Shaanxi Normal University, Xi'an, 710062, People's Republic of China.
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9
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Edwards MB, Ballerini ES, Kramer EM. Complex developmental and transcriptional dynamics underlie pollinator-driven evolutionary transitions in nectar spur morphology in Aquilegia (columbine). AMERICAN JOURNAL OF BOTANY 2022; 109:1360-1381. [PMID: 35971626 DOI: 10.1002/ajb2.16046] [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: 03/24/2022] [Revised: 07/17/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
PREMISE Determining the developmental programs underlying morphological variation is key to elucidating the evolutionary processes that generated the stunning biodiversity of the angiosperms. Here, we characterized the developmental and transcriptional dynamics of the elaborate petal nectar spur of Aquilegia (columbine) in species with contrasting pollination syndromes and spur morphologies. METHODS We collected petal epidermal cell number and length data across four Aquilegia species, two with short, curved nectar spurs of the bee-pollination syndrome and two with long, straight spurs of the hummingbird-pollination syndrome. We also performed RNA-seq on A. brevistyla (bee) and A. canadensis (hummingbird) distal and proximal spur compartments at multiple developmental stages. Finally, we intersected these data sets with a previous QTL mapping study on spur length and shape to identify new candidate loci. RESULTS The differential growth between the proximal and distal surfaces of curved spurs is primarily driven by differential cell division. However, independent transitions to straight spurs in the hummingbird syndrome have evolved by increasing differential cell elongation between spur surfaces. The RNA-seq data reveal these tissues to be transcriptionally distinct and point to auxin signaling as being involved with the differential cell elongation responsible for the evolution of straight spurs. We identify several promising candidate genes for future study. CONCLUSIONS Our study, taken together with previous work in Aquilegia, reveals the complexity of the developmental mechanisms underlying trait variation in this system. The framework we established here will lead to exciting future work examining candidate genes and processes involved in the rapid radiation of the genus.
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Affiliation(s)
- Molly B Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA, 02138, USA
| | - Evangeline S Ballerini
- Department of Biological Sciences, California State University Sacramento, 6000 J St., Sacramento, CA, 95819, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA, 02138, USA
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10
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Guo K, Huang C, Miao Y, Cosgrove DJ, Hsia KJ. Leaf morphogenesis: The multifaceted roles of mechanics. MOLECULAR PLANT 2022; 15:1098-1119. [PMID: 35662674 DOI: 10.1016/j.molp.2022.05.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/18/2022] [Accepted: 05/26/2022] [Indexed: 05/12/2023]
Abstract
Plants produce a rich diversity of biological forms, and the diversity of leaves is especially notable. Mechanisms of leaf morphogenesis have been studied in the past two decades, with a growing focus on the interactive roles of mechanics in recent years. Growth of plant organs involves feedback by mechanical stress: growth induces stress, and stress affects growth and morphogenesis. Although much attention has been given to potential stress-sensing mechanisms and cellular responses, the mechanical principles guiding morphogenesis have not been well understood. Here we synthesize the overarching roles of mechanics and mechanical stress in multilevel and multiple stages of leaf morphogenesis, encompassing leaf primordium initiation, phyllotaxis and venation patterning, and the establishment of complex mature leaf shapes. Moreover, the roles of mechanics at multiscale levels, from subcellular cytoskeletal molecules to single cells to tissues at the organ scale, are articulated. By highlighting the role of mechanical buckling in the formation of three-dimensional leaf shapes, this review integrates the perspectives of mechanics and biology to provide broader insights into the mechanobiology of leaf morphogenesis.
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Affiliation(s)
- Kexin Guo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Changjin Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Daniel J Cosgrove
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| | - K Jimmy Hsia
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
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11
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Fu X, Shan H, Yao X, Cheng J, Jiang Y, Yin X, Kong H. Petal development and elaboration. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3308-3318. [PMID: 35275176 DOI: 10.1093/jxb/erac092] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/07/2022] [Indexed: 05/12/2023]
Abstract
Petals can be simple or elaborate, depending on whether they have complex basic structures and/or highly specialized epidermal modifications. It has been proposed that the independent origin and diversification of elaborate petals have promoted plant-animal interactions and, therefore, the evolutionary radiation of corresponding plant groups. Recent advances in floral development and evolution have greatly improved our understanding of the processes, patterns, and mechanisms underlying petal elaboration. In this review, we compare the developmental processes of simple and elaborate petals, concluding that elaborate petals can be achieved through four main paths of modifications (i.e. marginal elaboration, ventral elaboration, dorsal elaboration, and surface elaboration). Although different types of elaborate petals were formed through different types of modifications, they are all results of changes in the expression patterns of genes involved in organ polarity establishment and/or the proliferation, expansion, and differentiation of cells. The deployment of existing genetic materials to perform a new function was also shown to be a key to making elaborate petals during evolution.
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Affiliation(s)
- Xuehao Fu
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xu Yao
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jie Cheng
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongchao Jiang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaofeng Yin
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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12
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Yang S, Wang N, Kimani S, Li Y, Bao T, Ning G, Li L, Liu B, Wang L, Gao X. Characterization of Terpene synthase variation in flowers of wild aquilegia species from Northeastern Asia. HORTICULTURE RESEARCH 2022; 9:uhab020. [PMID: 35039842 PMCID: PMC8771452 DOI: 10.1093/hr/uhab020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 08/25/2021] [Accepted: 10/02/2021] [Indexed: 05/13/2023]
Abstract
There are several causes for the great diversity in floral terpenes. The terpene products are determined by the catalytic fidelity, efficiency and plasticity of the active sites of terpene synthases (TPSs). However, the molecular mechanism of TPS in catalyzing terpene biosynthesis and its evolutionary fate in wild plant species remain largely unknown. In this study, the functionality of terpene synthases and their natural variants were assessed in two Northeastern Asia endemic columbine species and their natural hybrid. Synoptically, TPS7, TPS8, and TPS9 were highly expressed in these Aquilegia species from the Zuojia population. The in vitro and in vivo enzymatic assays revealed that TPS7 and TPS8 mainly produced (+)-limonene and β-sesquiphellandrene, respectively, whereas TPS9 produced pinene, similar to the major components released from Aquilegia flowers. Multiple sequence alignment of Aquilegia TPS7 and TPS8 in the Zuojia population revealed amino acid polymorphisms. Domain swapping and amino acid substitution assays demonstrated that 413A, 503I and 529D had impacts on TPS7 catalytic activity, whereas 420G, 538F and 545 L affected the ratio of β-sesquiphellandrene to β-bisabolene in TPS8. Moreover, these key polymorphic amino acid residues were found in Aquilegia species from the Changbai Mountain population. Interestingly, amino acid polymorphisms in TPSs were present in individuals with low expression levels, and nonsynonymous mutations could impact the catalytic activity or product specificity of these genes. The results of this study will shed new light on the function and evolution of TPS genes in wild plant species and are beneficial to the modification of plant fragrances.
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Affiliation(s)
- Song Yang
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Ning Wang
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Shadrack Kimani
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
- School of Pure and Applied Sciences, Karatina University, Karatina, Kenya
| | - Yueqing Li
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Tingting Bao
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Guogui Ning
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Linfeng Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Li Wang
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
| | - Xiang Gao
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China
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13
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Strelin MM, Zattara EE, Ullrich K, Schallenberg-Rüdinger M, Rensing S. Delayed differentiation of epidermal cells walls can underlie pedomorphosis in plants: the case of pedomorphic petals in the hummingbird-pollinated Caiophora hibiscifolia (Loasaceae, subfam. Loasoideae) species. EvoDevo 2022; 13:1. [PMID: 34980236 PMCID: PMC8725396 DOI: 10.1186/s13227-021-00186-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/12/2021] [Indexed: 01/11/2023] Open
Abstract
Background Understanding the relationship between macroevolutionary diversity and variation in organism development is an important goal of evolutionary biology. Variation in the morphology of several plant and animal lineages is attributed to pedomorphosis, a case of heterochrony, where an ancestral juvenile shape is retained in an adult descendant. Pedomorphosis facilitated morphological adaptation in different plant lineages, but its cellular and molecular basis needs further exploration. Plant development differs from animal development in that cells are enclosed by cell walls and do not migrate. Moreover, in many plant lineages, the differentiated epidermis of leaves, and leaf-derived structures, such as petals, limits organ growth. We, therefore, proposed that pedomorphosis in leaves, and in leaf-derived structures, results from delayed differentiation of epidermal cells with respect to reproductive maturity. This idea was explored for petal evolution, given the importance of corolla morphology for angiosperm reproductive success. Results By comparing cell morphology and transcriptional profiles between 5 mm flower buds and mature flowers of an entomophile and an ornitophile Loasoideae species (a lineage that experienced transitions from bee- to hummingbird-pollination), we show that evolution of pedomorphic petals of the ornithophile species likely involved delayed differentiation of epidermal cells with respect to flower maturity. We also found that developmental mechanisms other than pedomorphosis might have contributed to evolution of corolla morphology. Conclusions Our results highlight a need for considering alternatives to the flower-centric perspective when studying the origin of variation in flower morphology, as this can be generated by developmental processes that are also shared with leaves. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13227-021-00186-x.
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Affiliation(s)
- Marina M Strelin
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina.
| | - Eduardo E Zattara
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina
| | - Kristian Ullrich
- Department of Evolutionary Biology, August Thienemann Str. 2, 24306, Plön, Germany
| | - Mareike Schallenberg-Rüdinger
- IZMB - Institut für Zelluläre und Molekulare Botanik, Abt. Molekulare Evolution, University of Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Stefan Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, Germany
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14
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Delpeuch P, Jabbour F, Damerval C, Schönenberger J, Pamperl S, Rome M, Nadot S. A flat petal as ancestral state for Ranunculaceae. FRONTIERS IN PLANT SCIENCE 2022; 13:961906. [PMID: 36212342 PMCID: PMC9532948 DOI: 10.3389/fpls.2022.961906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/23/2022] [Indexed: 05/19/2023]
Abstract
Ranunculaceae comprise ca. 2,500 species (ca. 55 genera) that display a broad range of floral diversity, particularly at the level of the perianth. Petals, when present, are often referred to as "elaborate" because they have a complex morphology. In addition, the petals usually produce and store nectar, which gives them a crucial functional role in the interaction with pollinators. Its morphological diversity and species richness make this family a particularly suitable model group for studying the evolution of complex morphologies. Our aims are (1) to reconstruct the ancestral form of the petal and evolutionary stages at the scale of Ranunculaceae, (2) to test the hypothesis that there are morphogenetic regions on the petal that are common to all species and that interspecific morphological diversity may be due to differences in the relative proportions of these regions during development. We scored and analyzed traits (descriptors) that characterize in detail the complexity of mature petal morphology in 32 genera. Furthermore, we described petal development using high resolution X-Ray computed tomography (HRX-CT) in six species with contrasting petal forms (Ficaria verna, Helleborus orientalis, Staphisagria picta, Aconitum napellus, Nigella damascena, Aquilegia vulgaris). Ancestral state reconstruction was performed using a robust and dated phylogeny of the family, allowing us to produce new hypotheses for petal evolution in Ranunculaceae. Our results suggest a flat ancestral petal with a short claw for the entire family and for the ancestors of all tribes except Adonideae. The elaborate petals that are present in different lineages have evolved independently, and similar morphologies are the result of convergent evolution.
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Affiliation(s)
- Pauline Delpeuch
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique et Evolution, Orsay, France
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
- *Correspondence: Pauline Delpeuch,
| | - Florian Jabbour
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - Catherine Damerval
- Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Génétique Quantitative et Evolution-Le Moulon, Gif-sur-Yvette, France
| | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Susanne Pamperl
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Maxime Rome
- Jardin du Lautaret, CNRS, Université Grenoble Alpes, Grenoble, France
| | - Sophie Nadot
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique et Evolution, Orsay, France
- Sophie Nadot,
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15
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Liao IT, Hileman LC, Roy R. On the horizon for nectar-related research. AMERICAN JOURNAL OF BOTANY 2021; 108:2326-2330. [PMID: 34642946 DOI: 10.1002/ajb2.1767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Irene T Liao
- Department of Molecular, Cell, and Developmental Biology, University of California-Los Angeles, 610 Charles E Young Dr East, Los Angeles, CA, 90095, USA
| | - Lena C Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS, 66045, USA
| | - Rahul Roy
- Department of Biology, St. Catherine University, 2004 Randolph Avenue, St. Paul, MN, 55105, USA
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16
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Galipot P, Gerber S, Le Guilloux M, Jabbour F, Damerval C. Micro- and Macroscale Patterns of Petal Morphogenesis in Nigella damascena (Ranunculaceae) Revealed by Geometric Morphometrics and Cellular Analyses. FRONTIERS IN PLANT SCIENCE 2021; 12:769246. [PMID: 34868166 PMCID: PMC8640125 DOI: 10.3389/fpls.2021.769246] [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: 09/01/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Petals, the inner organs in a differentiated perianth, generally play an important role in pollinator attraction. As such they exhibit an extraordinary diversity of shapes, sizes, and colors. Being involved in pollinator attraction and reward, they are privileged targets of evolution. The corolla of the Ranunculaceae species Nigella damascena consists of elaborate nectariferous petals, made of a stalk, upper, and lower lips forming a nectar pouch, shiny pseudonectaries, and pilose ears. While the main events of petal development are properly described, a few is known about the pattern of organ size and shape covariation and the cellular dynamics during development. In this study, we investigated the relationships between morphogenesis and growth of N. damascena petals using geometric morphometrics coupled with the study of cell characteristics. First, we found that petal shape and size dynamics are allometric during development and that their covariation suggests that petal shape change dynamics are exponentially slower than growth. We then found that cell proliferation is the major driver of shape patterning during development, while petal size dynamics are mostly driven by cell expansion. Our analyses provide a quantitative basis to characterize the relationships between shape, size, and cell characteristics during the development of an elaborate floral structure. Such studies lay the ground for future evo-devo investigations of the large morphological diversity observed in nectariferous structures, in Ranunculaceae and beyond.
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Affiliation(s)
- Pierre Galipot
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
- Génétique Quantitative et Evolution-Le Moulon, Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Gif-sur-Yvette, France
| | - Sylvain Gerber
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - Martine Le Guilloux
- Génétique Quantitative et Evolution-Le Moulon, Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Gif-sur-Yvette, France
| | - Florian Jabbour
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - Catherine Damerval
- Génétique Quantitative et Evolution-Le Moulon, Université Paris-Saclay, INRAE, CNRS, AgroParisTech, Gif-sur-Yvette, France
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17
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Conway SJ, Walcher-Chevillet CL, Salome Barbour K, Kramer EM. Brassinosteroids regulate petal spur length in Aquilegia by controlling cell elongation. ANNALS OF BOTANY 2021; 128:931-942. [PMID: 34508638 PMCID: PMC8577200 DOI: 10.1093/aob/mcab116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/10/2021] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS Aquilegia produce elongated, three-dimensional petal spurs that fill with nectar to attract pollinators. Previous studies have shown that the diversity of spur length across the Aquilegia genus is a key innovation that is tightly linked with its recent and rapid diversification into new ranges, and that evolution of increased spur lengths is achieved via anisotropic cell elongation. Previous work identified a brassinosteroid response transcription factor as being enriched in the early developing spur cup. Brassinosteroids are known to be important for cell elongation, suggesting that brassinosteroid-mediated response may be an important regulator of spur elongation and potentially a driver of spur length diversity in Aquilegia. In this study, we investigated the role of brassinosteroids in the development of the Aquilegia coerulea petal spur. METHODS We exogenously applied the biologically active brassinosteroid brassinolide to developing petal spurs to investigate spur growth under high hormone conditions. We used virus-induced gene silencing and gene expression experiments to understand the function of brassinosteroid-related transcription factors in A. coerulea petal spurs. KEY RESULTS We identified a total of three Aquilegia homologues of the BES1/BZR1 protein family and found that these genes are ubiquitously expressed in all floral tissues during development, yet, consistent with the previous RNAseq study, we found that two of these paralogues are enriched in early developing petals. Exogenously applied brassinosteroid increased petal spur length due to increased anisotropic cell elongation as well as cell division. We found that targeting of the AqBEH genes with virus-induced gene silencing resulted in shortened petals, a phenotype caused in part by a loss of cell anisotropy. CONCLUSIONS Collectively, our results support a role for brassinosteroids in anisotropic cell expansion in Aquilegia petal spurs and highlight the brassinosteroid pathway as a potential player in the diversification of petal spur length in Aquilegia.
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Affiliation(s)
- Stephanie J Conway
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Cristina L Walcher-Chevillet
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
- 10x Genomics Inc., 6230 Stoneridge Mall Road, Pleasanton, CA 94588, USA
| | - Kate Salome Barbour
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
- Abramson Cancer Center, University of Pennsylvania, 3400 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
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18
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Strelin MM, Cosacov A, Chalcoff VR, Maubecin CC, Sérsic AN, Benitez-Vieyra SM. The role of ontogenetic allometry and nonallometric flower shape variation in species-level adaptive diversification - Calceolaria polyrhiza (Calceolariaceae) as a case study. Evol Dev 2021; 23:231-243. [PMID: 33372721 DOI: 10.1111/ede.12363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/08/2020] [Accepted: 11/14/2020] [Indexed: 12/14/2022]
Abstract
Organism shape changes predictably during ontogeny, resulting in specific patterns of ontogenetic allometry. In several plant and animal lineages, among-species variation in the shape of mature organisms mirrors variation along their growth trajectories. Hence, ontogenetic allometry is an important bias in evolution. This bias should be stronger at reduced evolutionary time scales, in which among-trait correlations had less time to evolve. Nevertheless, it was shown that adaptation of organism shape frequently involved departures from the ancestral ontogenetic allometry. Moreover, only a moderate fraction of shape variation is correlated with size during ontogeny. Hence, nonallometric variation in shape (NAVSh) is likely to contribute to adaptation, even at reduced evolutionary time scales. We explored the contributions of allometric variation in shape (AVSh), NAVSh, and size variation to adaptive evolution in the angiosperm species Calceolaria polyrhiza. This strongly relies on oil-collecting bees for pollination and experienced transitions in the size of pollinators during the last 2 Ma. Using geometric morphometrics, we described corolla morphology in several populations across its distribution range. Variation in corolla shape was decomposed into an allometric and a nonallometric component, and corolla size was estimated. We then looked for the correlation between these aspects of morphology and the pollinator. Our results suggest that adaptation to pollinators with different sizes relied on NAVSh, which resulted from shifts in the allometric slope and from shape changes that occurred early in flower development. We conclude that NAVSh can contribute to adaptation in flowering plants, even at the species-level.
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Affiliation(s)
- Marina M Strelin
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina
| | - Andrea Cosacov
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV (CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina
| | - Vanina R Chalcoff
- Grupo de Investigación en Ecología de la Polinización, Laboratorio Ecotono, INIBIOMA (CONICET - Universidad Nacional del Comahue), San Carlos de Bariloche, Río Negro, Argentina
| | - Constanza C Maubecin
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV (CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina
| | - Alicia N Sérsic
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV (CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina
| | - Santiago M Benitez-Vieyra
- Laboratorio de Ecología Evolutiva y Biología Floral, IMBIV (CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina
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19
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Gurung V, Yuan YW, Diggle PK. Comparative analysis of corolla tube development across three closely related Mimulus species with different pollination syndromes. Evol Dev 2021; 23:244-255. [PMID: 33410592 DOI: 10.1111/ede.12368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/14/2020] [Accepted: 12/18/2020] [Indexed: 01/24/2023]
Abstract
Fusion of petals to form a corolla tube is considered a key innovation contributing to the diversification of many flowering plant lineages. Corolla tube length often varies dramatically among species and is a major determinant of pollinator preference. However, our understanding of the developmental dynamics underlying corolla tube length variation is very limited. Here we examined corolla tube growth in the Mimulus lewisii species complex, an emerging model system for studying the developmental genetics and evo-devo of pollinator-associated floral traits. We compared developmental and cellular processes associated with corolla tube length variation among the bee-pollinated M. lewisii, the hummingbird-pollinated Mimulus verbenaceus, and the self-pollinated Mimulus parishii. We found that in all three species, cell size is non-uniformly distributed along the mature tube, with the longest cells just distal to the stamen insertion site. Differences in corolla tube length among the three species are not associated with processes of organogenesis or early development but are associated with variation in multiple processes occurring later in development, including the location and duration of cell division and cell elongation. The tube growth curves of the small-flowered M. parishii and large-flowered M. lewisii are essentially indistinguishable, except that M. parishii tubes stop growing earlier at a smaller size, suggesting a critical role of heterochrony in the shift from outcrossing to selfing. These results not only highlight the developmental process associated with corolla tube variation among species but also provide a baseline reference for future developmental genetic analyses of mutants or transgenic plants with altered corolla tube morphology in this emerging model system.
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Affiliation(s)
- Vandana Gurung
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Yao-Wu Yuan
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Pamela K Diggle
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
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20
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Kramer EM. My favourite flowering image: an Aquilegia flower. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:e1-e3. [PMID: 33382893 PMCID: PMC8611718 DOI: 10.1093/jxb/erz035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard
University, Cambridge, USA
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21
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Duffy D, Biggins JS. Defective nematogenesis: Gauss curvature in programmable shape-responsive sheets with topological defects. SOFT MATTER 2020; 16:10935-10945. [PMID: 33140798 DOI: 10.1039/d0sm01192d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Flat sheets encoded with patterns of contraction/elongation morph into curved surfaces. If the surfaces bear Gauss curvature, the resulting actuation can be strong and powerful. We deploy the Gauss-Bonnet theorem to deduce the Gauss curvature encoded in a pattern of uniform-magnitude contraction/elongation with spatially varying direction, as is commonly implemented in patterned liquid crystal elastomers. This approach reveals two fundamentally distinct contributions: a structural curvature which depends on the precise form of the pattern, and a topological curvature generated by defects in the contractile direction. These curvatures grow as different functions of the contraction/elongation magnitude, explaining the apparent contradiction between previous calculations for simple +1 defects, and smooth defect-free patterns. We verify these structural and topological contributions by conducting numerical shell calculations on sheets encoded with simple higher-order contractile defects to reveal their activated morphology. Finally we calculate the Gauss curvature generated by patterns with spatially varying magnitude and direction, which leads to additional magnitude gradient contributions to the structural term. We anticipate this form will be useful whenever magnitude and direction are natural variables, including in describing the contraction of a muscle along its patterned fiber direction, or a tissue growing by elongating its cells.
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Affiliation(s)
- Daniel Duffy
- Engineering Dept., University of Cambridge, Trumpington St., Cambridge, CB2 1PZ, UK.
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22
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Wessinger CA, Hileman LC. Parallelism in Flower Evolution and Development. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-011720-124511] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flower evolution is characterized by widespread repetition, with adaptations to pollinator environment evolving in parallel. Recent studies have expanded our understanding of the developmental basis of adaptive floral novelties—petal fusion, bilateral symmetry, heterostyly, and floral dimensions. In this article, we describe patterns of trait evolution and review developmental genetic mechanisms underlying floral novelties. We discuss the diversity of mechanisms for parallel adaptation, the evidence for constraints on these mechanisms, and how constraints help explain observed macroevolutionary patterns. We describe parallel evolution resulting from similarities at multiple hierarchical levels—genetic, developmental, morphological, functional—which indicate general principles in floral evolution, including the central role of hormone signaling. An emerging pattern is mutational bias that may contribute to rapid patterns of parallel evolution, especially if the derived trait can result from simple degenerative mutations. We argue that such mutational bias may be less likely to govern the evolution of novelties patterned by complex developmental pathways.
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Affiliation(s)
- Carolyn A. Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA
| | - Lena C. Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045, USA
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23
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Ballerini ES, Min Y, Edwards MB, Kramer EM, Hodges SA. POPOVICH, encoding a C2H2 zinc-finger transcription factor, plays a central role in the development of a key innovation, floral nectar spurs, in Aquilegia. Proc Natl Acad Sci U S A 2020; 117:22552-22560. [PMID: 32848061 PMCID: PMC7486772 DOI: 10.1073/pnas.2006912117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The evolution of novel features, such as eyes or wings, that allow organisms to exploit their environment in new ways can lead to increased diversification rates. Therefore, understanding the genetic and developmental mechanisms involved in the origin of these key innovations has long been of interest to evolutionary biologists. In flowering plants, floral nectar spurs are a prime example of a key innovation, with the independent evolution of spurs associated with increased diversification rates in multiple angiosperm lineages due to their ability to promote reproductive isolation via pollinator specialization. As none of the traditional plant model taxa have nectar spurs, little is known about the genetic and developmental basis of this trait. Nectar spurs are a defining feature of the columbine genus Aquilegia (Ranunculaceae), a lineage that has experienced a relatively recent and rapid radiation. We use a combination of genetic mapping, gene expression analyses, and functional assays to identify a gene crucial for nectar spur development, POPOVICH (POP), which encodes a C2H2 zinc-finger transcription factor. POP plays a central role in regulating cell proliferation in the Aquilegia petal during the early phase (phase I) of spur development and also appears to be necessary for the subsequent development of nectaries. The identification of POP opens up numerous avenues for continued scientific exploration, including further elucidating of the genetic pathway of which it is a part, determining its role in the initial evolution of the Aquilegia nectar spur, and examining its potential role in the subsequent evolution of diverse spur morphologies across the genus.
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Affiliation(s)
- Evangeline S Ballerini
- Ecology, Evolution and Marine Biology Department, University of California, Santa Barbara, CA 93106;
| | - Ya Min
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02318
| | - Molly B Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02318
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02318
| | - Scott A Hodges
- Ecology, Evolution and Marine Biology Department, University of California, Santa Barbara, CA 93106;
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Zhang R, Min Y, Holappa LD, Walcher-Chevillet CL, Duan X, Donaldson E, Kong H, Kramer EM. A role for the Auxin Response Factors ARF6 and ARF8 homologs in petal spur elongation and nectary maturation in Aquilegia. THE NEW PHYTOLOGIST 2020; 227:1392-1405. [PMID: 32356309 DOI: 10.1111/nph.16633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
The petal spur of the basal eudicot Aquilegia is a key innovation associated with the adaptive radiation of the genus. Previous studies have shown that diversification of Aquilegia spur length can be predominantly attributed to variation in cell elongation. However, the genetic pathways that control the development of petal spurs are still being investigated. Here, we focus on a pair of closely related homologs of the AUXIN RESPONSE FACTOR family, AqARF6 and AqARF8, to explore their roles in Aquileiga coerulea petal spur development. Expression analyses of the two genes show that they are broadly expressed in vegetative and floral organs, but have relatively higher expression in petal spurs, particularly at later stages. Knockdown of the two AqARF6 and AqARF8 transcripts using virus-induced gene silencing resulted in largely petal-specific defects, including a significant reduction in spur length due to a decrease in cell elongation. These spurs also exhibited an absence of nectar production, which was correlated with downregulation of STYLISH homologs that have previously been shown to control nectary development. This study provides the first evidence of ARF6/8 homolog-mediated petal development outside the core eudicots. The genes appear to be specifically required for cell elongation and nectary maturation in the Aquilegia petal spur.
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Affiliation(s)
- Rui Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Ya Min
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA, 02138, USA
| | - Lynn D Holappa
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA, 02138, USA
| | - Cristina L Walcher-Chevillet
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA, 02138, USA
- 10x Genomics, 6230 Stoneridge Mall Road, Pleasanton, CA, 94588-3260, USA
| | - Xiaoshan Duan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- Harvard University Herbaria, Harvard University, 22 Divinity Ave, Cambridge, MA, 02138, USA
| | - Emily Donaldson
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA, 02138, USA
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA, 02138, USA
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Jiang Y, Wang M, Zhang R, Xie J, Duan X, Shan H, Xu G, Kong H. Identification of the target genes of AqAPETALA3-3 (AqAP3-3) in Aquilegia coerulea (Ranunculaceae) helps understand the molecular bases of the conserved and nonconserved features of petals. THE NEW PHYTOLOGIST 2020; 227:1235-1248. [PMID: 32285943 DOI: 10.1111/nph.16601] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
Identification and comparison of the conserved and variable downstream genes of floral organ identity regulators are critical to understanding the mechanisms underlying the commonalities and peculiarities of floral organs. Yet, because of the lack of studies in nonmodel species, a general picture of the regulatory evolution between floral organ identity genes and their targets is still lacking. Here, by conducting extensive chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), electrophoretic mobility shift assay and bioinformatic analyses, we identify and predict the target genes of a petal identity gene, AqAPETALA3-3 (AqAP3-3), in Aquilegia coerulea (Ranunculaceae) and compare them with those of its counterpart in Arabidopsis thaliana, AP3. In total, 7049 direct target genes are identified for AqAP3-3, of which 2394 are highly confident and 1085 are shared with AP3. Gene Ontology enrichment analyses further indicate that conserved targets are largely involved in the formation of identity-related features, whereas nonconserved targets are mostly required for the formation of species-specific features. These results not only help understand the molecular bases of the conserved and nonconserved features of petals, but also pave the way to studying the regulatory evolution between floral organ identity genes and their targets.
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Affiliation(s)
- Yongchao Jiang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Meimei Wang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rui Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jinghe Xie
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoshan Duan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Guixia Xu
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Meaders C, Min Y, Freedberg KJ, Kramer E. Developmental and molecular characterization of novel staminodes in Aquilegia. ANNALS OF BOTANY 2020; 126:231-243. [PMID: 32068783 PMCID: PMC7380458 DOI: 10.1093/aob/mcaa029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/17/2020] [Indexed: 05/29/2023]
Abstract
BACKGROUND AND AIMS The ranunculid model system Aquilegia is notable for the presence of a fifth type of floral organ, the staminode, which appears to be the result of sterilization and modification of the two innermost whorls of stamens. Previous studies have found that the genetic basis for the identity of this new organ is the result of sub- and neofunctionalization of floral organ identity gene paralogues; however, we do not know the extent of developmental and molecular divergence between stamens and staminodes. METHODS We used histological techniques to describe the development of the Aquilegia coerulea 'Origami' staminode relative to the stamen filament. These results have been compared with four other Aquilegia species and the closely related genera Urophysa and Semiaquilegia. As a complement, RNA sequencing has been conducted at two developmental stages to investigate the molecular divergence of the stamen filaments and staminodes in A. coerulea 'Origami'. KEY RESULTS Our developmental study has revealed novel features of staminode development, most notably a physical interaction along the lateral margin of adjacent organs that appears to mediate their adhesion. In addition, patterns of abaxial/adaxial differentiation are observed in staminodes but not stamen filaments, including asymmetric lignification of the adaxial epidermis in the staminodes. The comparative transcriptomics are consistent with the observed lignification of staminodes and indicate that stamen filaments are radialized due to overexpression of adaxial identity, while the staminodes are expanded due to the balanced presence of abaxial identity. CONCLUSIONS These findings suggest a model in which the novel staminode identity programme interacts with the abaxial/adaxial identity pathways to produce two whorls of laterally expanded organs that are highly differentiated along their abaxial/adaxial axis. While the ecological function of Aquilegia staminodes remains to be determined, these data are consistent with a role in protecting the early carpels from herbivory and/or pathogens.
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Affiliation(s)
- Clara Meaders
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Ya Min
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Katherine J Freedberg
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Tufts University School of Medicine, Boston, MA, USA
| | - Elena Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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Xie J, Zhao H, Li K, Zhang R, Jiang Y, Wang M, Guo X, Yu B, Kong H, Jiao Y, Xu G. A chromosome-scale reference genome of Aquilegia oxysepala var. kansuensis. HORTICULTURE RESEARCH 2020; 7:113. [PMID: 32637141 PMCID: PMC7326910 DOI: 10.1038/s41438-020-0328-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 05/21/2023]
Abstract
The genus Aquilegia (Ranunculaceae) has been cultivated as ornamental and medicinal plants for centuries. With petal spurs of strikingly diverse size and shape, Aquilegia has also been recognized as an excellent system for evolutionary studies. Pollinator-mediated selection for longer spurs is believed to have shaped the evolution of this genus, especially the North American taxa. Recently, however, an opposite evolutionary trend was reported in an Asian lineage, where multiple origins of mini- or even nonspurred morphs have occurred. Interesting as it is, the lack of genomic resources has limited our ability to decipher the molecular and evolutionary mechanisms underlying spur reduction in this special lineage. Using long-read sequencing (PacBio Sequel), in combination with optical maps (BioNano DLS) and Hi-C, we assembled a high-quality reference genome of A. oxysepala var. kansuensis, a sister species to the nonspurred taxon. The final assembly is approximately 293.2 Mb, 94.6% (277.4 Mb) of which has been anchored to 7 pseudochromosomes. A total of 25,571 protein-coding genes were predicted, with 97.2% being functionally annotated. When comparing this genome with that of A. coerulea, we detected a large rearrangement between Chr1 and Chr4, which might have caused the Chr4 of A. oxysepala var. kansuensis to partly deviate from the "decaying" path that was taken before the split of Aquilegia and Semiaquilegia. This high-quality reference genome is fundamental to further investigations on the development and evolution of petal spurs and provides a strong foundation for the breeding of new horticultural Aquilegia cultivars.
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Affiliation(s)
- Jinghe Xie
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Haifeng Zhao
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Kunpeng Li
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Rui Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
| | - Yongchao Jiang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
| | - Meimei Wang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xuelian Guo
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
| | - Ben Yu
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yuannian Jiao
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Guixia Xu
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
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Singh S, Bhatt V, Kumar V, Kumawat S, Khatri P, Singla P, Shivaraj S, Nadaf A, Deshmukh R, Sharma TR, Sonah H. Evolutionary Understanding of Aquaporin Transport System in the Basal Eudicot Model Species Aquilegia coerulea. PLANTS 2020; 9:plants9060799. [PMID: 32604788 PMCID: PMC7355465 DOI: 10.3390/plants9060799] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/07/2020] [Accepted: 06/22/2020] [Indexed: 01/02/2023]
Abstract
Aquaporins (AQPs) play a pivotal role in the cellular transport of water and many other small solutes, influencing many physiological and developmental processes in plants. In the present study, extensive bioinformatics analysis of AQPs was performed in Aquilegia coerulea L., a model species belonging to basal eudicots, with a particular focus on understanding the AQPs role in the developing petal nectar spur. A total of 29 AQPs were identified in Aquilegia, and their phylogenetic analysis performed with previously reported AQPs from rice, poplar and Arabidopsis depicted five distinct subfamilies of AQPs. Interestingly, comparative analysis revealed the loss of an uncharacterized intrinsic protein II (XIP-II) group in Aquilegia. The absence of the entire XIP subfamily has been reported in several previous studies, however, the loss of a single clade within the XIP family has not been characterized. Furthermore, protein structure analysis of AQPs was performed to understand pore diversity, which is helpful for the prediction of solute specificity. Similarly, an AQP AqcNIP2-1 was identified in Aquilegia, predicted as a silicon influx transporter based on the presence of features such as the G-S-G-R aromatic arginine selectivity filter, the spacing between asparagine-proline-alanine (NPA) motifs and pore morphology. RNA-seq analysis showed a high expression of tonoplast intrinsic proteins (TIPs) and plasma membrane intrinsic proteins (PIPs) in the developing petal spur. The results presented here will be helpful in understanding the AQP evolution in Aquilegia and their expression regulation, particularly during floral development.
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Affiliation(s)
- Shweta Singh
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - Vacha Bhatt
- Department of Botany, Savitribai Phule Pune University, Pune, Maharashtra 411007, India; (V.B.); (A.N.)
| | - Virender Kumar
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - Surbhi Kumawat
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Praveen Khatri
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - Pankaj Singla
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - S.M. Shivaraj
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - Altaf Nadaf
- Department of Botany, Savitribai Phule Pune University, Pune, Maharashtra 411007, India; (V.B.); (A.N.)
| | - Rupesh Deshmukh
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
| | - Tilak Raj Sharma
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
- Division of Crop Science, Indian Council of Agricultural Research, Krishi Bhavan, New Delhi 110001, India
- Correspondence: (T.R.S.); (H.S.); Tel.: +91-172-522-1181 (H.S.)
| | - Humira Sonah
- National Agri-Food Biotechnology Institute (NABI), Mohali Punjab 140306, India; (S.S.); (V.K.); (S.K.); (P.K.); (P.S.); (S.M.S.); (R.D.)
- Correspondence: (T.R.S.); (H.S.); Tel.: +91-172-522-1181 (H.S.)
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Zhou ZL, Duan YW, Luo Y, Yang YP, Zhang ZQ. Cell number explains the intraspecific spur-length variation in an Aquilegia species. PLANT DIVERSITY 2019; 41:307-314. [PMID: 31934675 PMCID: PMC6951270 DOI: 10.1016/j.pld.2019.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Variations of nectar spur length allow pollinators to utilize resources in novel ways, leading to the different selective pressures on spurs and allowing taxa to diversify. However, the mechanisms underlying spur length variation remain unclear. Interspecific comparisons of spur length suggest that both cell division and anisotropic expansion could explain the changes of spur length, and that hormone-related genes contribute to the process of spur formation. In contrast, little is known about intraspecific spur length variation. In Aquilegia rockii, spur length varies strikingly, ranging from 1 mm to 18 mm. To examine the potential mechanisms underlying spur length variation in A. rockii, we observed cell morphology and analyzed RNA-seq of short- and long-spurred flowers. Scanning electron microscopy revealed that at two positions on spurs there were no differences in either cell density or cell anisotropy between short- and long-spurred flowers, suggesting that in A. rockii changes in cell number may explain variations in spur length. In addition, we screened transcriptomes of short- and long-spurred flowers for differentially expressed genes; this screen identified several genes linked to cell division (e.g., F-box, CDKB2-2, and LST8), a finding which is consistent with our analysis of the cellular morphology of spurs. However, we did not find any highly expressed genes involved in the hormone pathway in long-spurred flowers. In contrast to previous hypotheses that anisotropic cell expansion leads to interspecific spur variation in Aquilegia, our results suggest that cell number changes and related genes are mainly responsible for spur length variations of A. rockii. Furthermore, the underlying mechanisms of similar floral traits in morphology may be quite different, enriching our understanding of the mechanisms of flower diversity in angiosperms.
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Affiliation(s)
- Zhi-Li Zhou
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan-Wen Duan
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yan Luo
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China
| | - Yong-Ping Yang
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Zhi-Qiang Zhang
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, 650091, China
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Shan H, Cheng J, Zhang R, Yao X, Kong H. Developmental mechanisms involved in the diversification of flowers. NATURE PLANTS 2019; 5:917-923. [PMID: 31477891 DOI: 10.1038/s41477-019-0498-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 07/18/2019] [Indexed: 05/08/2023]
Abstract
We all appreciate the fantastic diversity of flowers. How flowers diversified, however, remains largely enigmatic. The mechanisms underlying the diversification of flowers are complex because the overall appearance of a flower is determined by many factors, such as the shape and size of its receptacle, and the arrangement, number, type, shape and colour of floral organs. Modifications of the developmental trajectories of a flower and its components, therefore, can lead to the generation of new floral types. In this Review, by summarizing the recent progress in studying the initiation, identity determination, morphogenesis and maturation of floral organs, we present our current understanding of the mechanisms underlying the diversification of flowers.
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Affiliation(s)
- Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jie Cheng
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Rui Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xu Yao
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
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Ballerini ES, Kramer EM, Hodges SA. Comparative transcriptomics of early petal development across four diverse species of Aquilegia reveal few genes consistently associated with nectar spur development. BMC Genomics 2019; 20:668. [PMID: 31438840 PMCID: PMC6704642 DOI: 10.1186/s12864-019-6002-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/26/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Petal nectar spurs, which facilitate pollination through animal attraction and pollen placement, represent a key innovation promoting diversification in the genus Aquilegia (Ranunculaceae). Identifying the genetic components that contribute to the development of these three-dimensional structures will inform our understanding of the number and types of genetic changes that are involved in the evolution of novel traits. In a prior study, gene expression between two regions of developing petals, the laminar blade and the spur cup, was compared at two developmental stages in the horticultural variety A. coerulea 'Origami'. Several hundred genes were differentially expressed (DE) between the blade and spur at both developmental stages. In order to narrow in on a set of genes crucial to early spur formation, the current study uses RNA sequencing (RNAseq) to conduct comparative expression analyses of petals from five developmental stages between four Aquilegia species, three with morphologically variable nectar spurs, A. sibirica, A. formosa, and A. chrysantha, and one that lacks nectar spurs, A. ecalcarata. RESULTS Petal morphology differed increasingly between taxa across the developmental stages assessed, with petals from all four taxa being indistinguishable pre-spur formation at developmental stage 1 (DS1) and highly differentiated by developmental stage 5 (DS5). In all four taxa, genes involved in mitosis were down-regulated over the course of the assessed developmental stages, however, many genes involved in mitotic processes remained expressed at higher levels later in development in the spurred taxa. A total of 690 genes were identified that were consistently DE between the spurred taxa and A. ecalcarata at all five developmental stages. By comparing these genes with those identified as DE between spur and blade tissue in A. coerulea 'Origami', a set of only 35 genes was identified that shows consistent DE between petal samples containing spur tissue versus those without spur tissue. CONCLUSIONS The results of this study suggest that expression differences in very few loci are associated with the presence and absence of spurs. In general, it appears that the spurless petals of A. ecalcarata cease cell divisions and enter the cell differentiation phase at an earlier developmental time point than those that produce spurs. This much more tractable list of 35 candidates genes will greatly facilitate targeted functional studies to assess the genetic control and evolution of petal spurs in Aquilegia.
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Affiliation(s)
- Evangeline S. Ballerini
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA USA
- Current Address: Department of Biological Sciences, Sacramento State University, Sacramento, CA USA
| | - Elena M. Kramer
- Organismic and Evolutionary Biology Department, Harvard University, Cambridge, MA USA
| | - Scott A. Hodges
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA USA
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32
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Yao X, Zhang W, Duan X, Yuan Y, Zhang R, Shan H, Kong H. The making of elaborate petals in Nigella through developmental repatterning. THE NEW PHYTOLOGIST 2019; 223:385-396. [PMID: 30889278 DOI: 10.1111/nph.15799] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 03/08/2019] [Indexed: 05/20/2023]
Abstract
Elaborate petals are present in many flowering plants lineages and have greatly promoted the success and evolutionary radiation of these groups. How elaborate petals are made, however, remains largely unclear. Petals of Nigella (Ranunculaceae) have long been recognized as elaborate and can thus be an excellent model for the study of petal elaboration. Here, by conducting detailed morphological, micromorphological, anatomical, developmental and evolutionary studies on the petals of Nigella species, we explored the processes, general patterns and underlying mechanisms of petal elaboration. We found that petals of Nigella are highly complex, and the complexity can be reflected at various levels. We also found that evolutionary elaboration of the Nigella petals is a gradual process, involving not only modifications of pre-existing structures but also de novo origination of new characters. Further investigations indicated that the elaboration and diversification of Nigella petals were accomplished by modifying the ancestral trajectory of petal development, a process known as developmental repatterning. Our results not only provide new insights into the development and evolution of elaborate petals, but also highlight the necessity of conducting multiple-level investigations for understanding the processes, patterns and underlying mechanisms of plant evolution.
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Affiliation(s)
- Xu Yao
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wengen Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaoshan Duan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yi Yuan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rui Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Fernández-Mazuecos M, Blanco-Pastor JL, Juan A, Carnicero P, Forrest A, Alarcón M, Vargas P, Glover BJ. Macroevolutionary dynamics of nectar spurs, a key evolutionary innovation. THE NEW PHYTOLOGIST 2019; 222:1123-1138. [PMID: 30570752 DOI: 10.1111/nph.15654] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/11/2018] [Indexed: 05/27/2023]
Abstract
Floral nectar spurs are widely considered a key innovation promoting diversification in angiosperms by means of pollinator shifts. We investigated the macroevolutionary dynamics of nectar spurs in the tribe Antirrhineae (Plantaginaceae), which contains 29 genera and 300-400 species (70-80% spurred). The effect of nectar spurs on diversification was tested, with special focus on Linaria, the genus with the highest number of species. We generated the most comprehensive phylogeny of Antirrhineae to date and reconstructed the evolution of nectar spurs. Diversification rate heterogeneity was investigated using trait-dependent and trait-independent methods, and accounting for taxonomic uncertainty. The association between changes in spur length and speciation was examined within Linaria using model testing and ancestral state reconstructions. We inferred four independent acquisitions of nectar spurs. Diversification analyses revealed that nectar spurs are loosely associated with increased diversification rates. Detected rate shifts were delayed by 5-15 Myr with respect to the acquisition of the trait. Active evolution of spur length, fitting a speciational model, was inferred in Linaria, which is consistent with a scenario of pollinator shifts driving diversification. Nectar spurs played a role in diversification of the Antirrhineae, but diversification dynamics can only be fully explained by the complex interaction of multiple biotic and abiotic factors.
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Affiliation(s)
- Mario Fernández-Mazuecos
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014, Madrid, Spain
| | - José Luis Blanco-Pastor
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014, Madrid, Spain
- INRA, Centre Nouvelle-Aquitaine-Poitiers, UR4 (URP3F), 86600, Lusignan, France
| | - Ana Juan
- Departamento de Ciencias Ambientales y Recursos Naturales (dCARN) & Instituto de la Biodiversidad (CIBIO), Universidad de Alicante, PO Box 99, 03080, Alicante, Spain
| | - Pau Carnicero
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Alan Forrest
- Centre for Middle Eastern Plants, Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh, EH3 5LR, UK
| | - Marisa Alarcón
- Institut Botànic de Barcelona (IBB-CSIC-ICUB), Passeig del Migdia s/n, Parc de Montjuïc, 08038, Barcelona, Spain
| | - Pablo Vargas
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014, Madrid, Spain
| | - Beverley J Glover
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
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Yu F, Zhao YC, Huang H. The complete chloroplast genome of aquilegia rockii, an endemic herb plant in Western China. Mitochondrial DNA B Resour 2019. [DOI: 10.1080/23802359.2019.1607580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Fei Yu
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, College of Biological and Food Engineering, Huaihua University, Huaihua, China
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Yu-Chen Zhao
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, College of Biological and Food Engineering, Huaihua University, Huaihua, China
| | - Hui Huang
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, College of Biological and Food Engineering, Huaihua University, Huaihua, China
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Plus ça change, plus c'est la même chose: The developmental evolution of flowers. Curr Top Dev Biol 2019; 131:211-238. [DOI: 10.1016/bs.ctdb.2018.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Cullen E, Fernández-Mazuecos M, Glover BJ. Evolution of nectar spur length in a clade of Linaria reflects changes in cell division rather than in cell expansion. ANNALS OF BOTANY 2018; 122:801-809. [PMID: 29370374 PMCID: PMC6215036 DOI: 10.1093/aob/mcx213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/08/2018] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Nectar spurs (tubular outgrowths of a floral organ which contain, or give the appearance of containing, nectar) are hypothesized to be a 'key innovation' which can lead to rapid speciation within a lineage, because they are involved in pollinator specificity. Despite the ecological importance of nectar spurs, relatively little is known about their development. We used a comparative approach to investigate variation in nectar spur length in a clade of eight Iberian toadflaxes. METHODS Spur growth was measured at the macroscopic level over time in all eight species, and growth rate and growth duration compared. Evolution of growth rate was reconstructed across the phylogeny. Within the clade we then focused on Linaria becerrae and Linaria clementei, a pair of sister species which have extremely long and short spurs, respectively. Characterization at a micromorphological level was performed across a range of key developmental stages to determine whether the difference in spur length is due to differential cell expansion or cell division. KEY RESULTS We detected a significant difference in the evolved growth rates, while developmental timing of both the initiation and the end of spur growth remained similar. Cell number is three times higher in the long spurred L. becerrae compared with L. clementei, whereas cell length is only 1.3 times greater. In addition, overall anisotropy of mature cells is not significantly different between the two species. CONCLUSIONS We found that changes in cell number and therefore in cell division largely explain evolution of spur length. This contrasts with previous studies in Aquilegia which have found that variation in nectar spur length is due to directed cell expansion (anisotropy) over variable time frames. Our study adds to knowledge about nectar spur development in a comparative context and indicates that different systems may have evolved nectar spurs using disparate mechanisms.
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Affiliation(s)
- E Cullen
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - M Fernández-Mazuecos
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- Real Jardín Botánico (RJB-CSIC), Madrid, Spain
| | - B J Glover
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
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Płachno BJ, Stpiczyńska M, Adamec L, Miranda VFO, Świątek P. Nectar trichome structure of aquatic bladderworts from the section Utricularia (Lentibulariaceae) with observation of flower visitors and pollinators. PROTOPLASMA 2018; 255:1053-1064. [PMID: 29404696 PMCID: PMC5994208 DOI: 10.1007/s00709-018-1216-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/26/2018] [Indexed: 05/09/2023]
Abstract
In Utricularia, the flower spur is a nectary and in this organ, nectar is produced and stored. This study aimed to examine the structure of the nectary trichomes in four Utricularia species (Utricularia vulgaris L., U. australis R.Br., U. bremii Heer and U. foliosa L.) from the generic section Utricularia. We have investigated whether species with different spur morphology had similar spur anatomy and nectary trichome structure. In Utricularia flowers, nectar is produced by spur capitate trichomes (sessile or stalked). Our results showed that regardless of the various spur morphology, trichomes have similar architecture and ultrastructure. Head cells of these trichomes are transfer cells with an eccrine nectar secretion. Examined species differed in the micromorphology of papillae in spurs. The fly Eristalis tenax was found to be a pollinator of U. vulgaris. Small Halictidae bees seem to be pollinators of U. foliosa.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, 9 Gronostajowa St, 30-387, Cracow, Poland.
| | - Małgorzata Stpiczyńska
- Botanic Garden, Faculty of Biology, University of Warsaw, Al. Ujazdowskie 4, 00-478, Warsaw, Poland
| | - Lubomír Adamec
- Section of Plant Ecology, Institute of Botany of the Czech Academy of Sciences, Dukelská 135, -37982, Třeboň, CZ, Czech Republic
| | - Vitor Fernandes Oliveira Miranda
- Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, Departamento de Biologia Aplicada à Agropecuária, Universidade Estadual Paulista (Unesp), São Paulo, Brazil
| | - Piotr Świątek
- Department of Animal Histology and Embryology, University of Silesia in Katowice, 9 Bankowa St, 40-007, Katowice, Poland
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Woźniak NJ, Sicard A. Evolvability of flower geometry: Convergence in pollinator-driven morphological evolution of flowers. Semin Cell Dev Biol 2018; 79:3-15. [DOI: 10.1016/j.semcdb.2017.09.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 01/01/2023]
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Tsai T, Diggle PK, Frye HA, Jones CS. Contrasting lengths of Pelargonium floral nectar tubes result from late differences in rate and duration of growth. ANNALS OF BOTANY 2018; 121:549-560. [PMID: 29293992 PMCID: PMC5838813 DOI: 10.1093/aob/mcx171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND AIMS Much of morphological evolution in flowers has arisen from pollinator-mediated selection, often manifest as a match between the length of the pollinator's proboscis and the depth of tubular corollas or spurs. We investigate development, growth and homology of the unique nectar tube of Pelargonium, frequently described as 'a spur adnate to the pedicel'. METHODS We focused on two species. The nectar tube of P. ionidiflorum is three times longer than that of P. odoratissimum. Light and scanning electron microscopy were carried out, and daily growth measurements were used to compare nectar tube development and vascular patterns. KEY RESULTS Nectar tubes in both species are initiated centripetally to the dorsal sepal in a space created by lateral displacement of two antepetalous stamens. The cavity deepens through subsequent intercalary growth of the receptacle that proceeds at the same rate in both species until tubes reach approx. 10 mm in length. Differences in final nectar tube lengths arise via an increase in the rate and duration of growth of the receptacle that begins just before anthesis (floral opening) and continues for several days past anthesis in P. ionidiflorum but does not occur in P. odoratissimum. Epidermal cells of the dorsal surface of the nectar tube in P. ionidiflorum are approx. 1.6 times longer than those in P. odoratissimum. Histological sections show no evidence that the nectar tube is a spur that became evolutionarily fused to the pedicel. CONCLUSIONS Nectar tubes in Pelargonium are localized cavities that form in the receptacle via intercalary growth. Differences in the rate and duration of growth just prior to and following anthesis underlie differences in final tube lengths. Because differences in cell lengths do not fully account for differences in nectar tube lengths, evolutionary diversification must involve changes in both cell cycle and cell expansion.
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Affiliation(s)
- Timothy Tsai
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Pamela K Diggle
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Henry A Frye
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Cynthia S Jones
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
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40
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Damerval C, Becker A. Genetics of flower development in Ranunculales - a new, basal eudicot model order for studying flower evolution. THE NEW PHYTOLOGIST 2017; 216:361-366. [PMID: 28052360 DOI: 10.1111/nph.14401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/20/2016] [Indexed: 05/20/2023]
Abstract
Contents 361 I. 361 II. 362 III. 363 IV. 364 V. 364 Acknowledgements 365 References 365 SUMMARY: Ranunculales, the sister group to all other eudicots, encompasses species with a remarkable floral diversity, which are currently emerging as new model organisms to address questions relating to the genetic architecture of flower morphology and its evolution. These questions concern either traits only found in members of the Ranunculales or traits that have convergently evolved in other large clades of flowering plants. We present recent results obtained on floral organ identity and number, symmetry evolution and spur formation in Ranunculales species. We discuss benefits and future prospects of evo-devo studies in Ranunculales, which can provide the opportunity to decipher the genetic architecture of novel floral traits and also to appraise the degree of conservation of genetic mechanisms involved in homoplasious traits.
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Affiliation(s)
- Catherine Damerval
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, 91190, France
| | - Annette Becker
- Justus-Liebig-Universität Gießen, Institut für Botanik, Heinrich-Buff-Ring 38, Gießen, 35392, Germany
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41
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Min Y, Kramer EM. The Aquilegia JAGGED homolog promotes proliferation of adaxial cell types in both leaves and stems. THE NEW PHYTOLOGIST 2017; 216:536-548. [PMID: 27864962 DOI: 10.1111/nph.14282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/14/2016] [Indexed: 06/06/2023]
Abstract
In order to explore the functional conservation of JAGGED, a key gene involved in the sculpting of lateral organs in several model species, we identified its ortholog AqJAG in the lower eudicot species Aquilegia coerulea. We analyzed the expression patterns of AqJAG in various tissues and developmental stages, and used RNAi-based methods to generate knockdown phenotypes of AqJAG. AqJAG was strongly expressed in shoot apices, floral meristems, lateral root primordia and all lateral organ primordia. Silencing of AqJAG revealed a wide range of defects in the developing stems, leaves and flowers; strongest phenotypes include severe reduction of leaflet laminae due to a decrease in cell size and number, change of adaxial cell identity, outgrowth of laminar-like tissue on the inflorescence stem, and early arrest of floral meristems and floral organ primordia. Our results indicate that AqJAG plays a critical role in controlling primordia initiation and distal growth of floral organs, and laminar development of leaflets. Most strikingly, we demonstrated that AqJAG disproportionally controls the behavior of cells with adaxial identity in vegetative tissues, providing evidence of how cell proliferation is controlled in an identity-specific manner.
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Affiliation(s)
- Ya Min
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA, 02138, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA, 02138, USA
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42
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Fernández-Mazuecos M, Glover BJ. The evo-devo of plant speciation. Nat Ecol Evol 2017; 1:110. [DOI: 10.1038/s41559-017-0110] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/07/2017] [Indexed: 11/09/2022]
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Ding B, Mou F, Sun W, Chen S, Peng F, Bradshaw HD, Yuan YW. A dominant-negative actin mutation alters corolla tube width and pollinator visitation in Mimulus lewisii. THE NEW PHYTOLOGIST 2017; 213:1936-1944. [PMID: 28164332 PMCID: PMC5300067 DOI: 10.1111/nph.14281] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/16/2016] [Indexed: 05/05/2023]
Abstract
A third of all angiosperm species produce flowers with petals fused into a corolla tube. The various elaborations of corolla tube attributes, such as length, width and curvature, have enabled plants to exploit many specialized pollinator groups. These elaborations often differ dramatically among closely related species, contributing to pollinator shift and pollinator-mediated reproductive isolation and speciation. However, very little is known about the genetic and developmental control of these corolla tube attributes. Here we report the characterization of a semi-dominant mutant in the monkeyflower species Mimulus lewisii, with a substantial decrease in corolla tube width but no change in tube length. This morphological alteration leads to a ˜ 70% decrease in bumblebee visitation rate for the homozygous mutant compared to the wild-type. Through bulk segregant analysis and transgenic experiment, we show that the mutant phenotype is caused by a dominant-negative mutation in an actin gene. This mutation decreases epidermal cell width but not length, and probably also reduces the number of lateral cell divisions. These results suggest a surprising potential role for a 'housekeeping' gene in fine-tuning the development of an ecologically important floral trait.
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Affiliation(s)
- Baoqing Ding
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs 06269, USA
| | - Fengjuan Mou
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs 06269, USA
- Faculty of Forestry, Southwest Forestry University, Kunming 650224, China
| | - Wei Sun
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Shilin Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Foen Peng
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | | | - Yao-Wu Yuan
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs 06269, USA
- Institute for Systems Genomics, University of Connecticut, Storrs 06269, USA
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Monniaux M, Hay A. Cells, walls, and endless forms. CURRENT OPINION IN PLANT BIOLOGY 2016; 34:114-121. [PMID: 27825067 DOI: 10.1016/j.pbi.2016.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 05/26/2023]
Abstract
A key question in biology is how the endless diversity of forms found in nature evolved. Understanding the cellular basis of this diversity has been aided by advances in non-model experimental systems, quantitative image analysis tools, and modeling approaches. Recent work in plants highlights the importance of cell wall and cuticle modifications for the emergence of diverse forms and functions. For example, explosive seed dispersal in Cardamine hirsuta depends on the asymmetric localization of lignified cell wall thickenings in the fruit valve. Similarly, the iridescence of Hibiscus trionum petals relies on regular striations formed by cuticular folds. Moreover, NAC transcription factors regulate the differentiation of lignified xylem vessels but also the water-conducting cells of moss that lack a lignified secondary cell wall, pointing to the origin of vascular systems. Other novel forms are associated with modified cell growth patterns, including oriented cell expansion or division, found in the long petal spurs of Aquilegia flowers, and the Sarracenia purpurea pitcher leaf, respectively. Another good example is the regulation of dissected leaf shape in C. hirsuta via local growth repression, controlled by the REDUCED COMPLEXITY HD-ZIP class I transcription factor. These studies in non-model species often reveal as much about fundamental processes of development as they do about the evolution of form.
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Affiliation(s)
- Marie Monniaux
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Köln, Germany
| | - Angela Hay
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
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45
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Wainwright PC, Price SA. The Impact of Organismal Innovation on Functional and Ecological Diversification. Integr Comp Biol 2016; 56:479-88. [DOI: 10.1093/icb/icw081] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Walcher-Chevillet CL, Kramer EM. Breaking the mold: understanding the evolution and development of lateral organs in diverse plant models. Curr Opin Genet Dev 2016; 39:79-84. [PMID: 27348252 DOI: 10.1016/j.gde.2016.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/24/2016] [Accepted: 06/07/2016] [Indexed: 12/25/2022]
Abstract
The formation of complex three-dimensional shape differs significantly between plants and animals due to the presence of the cell wall in the former, which prevents all cell migration. Instead, in lateral plant organs such as leaves or petals, shape is controlled by a series of developmental phases in which the organ acquires polarity, cells undergo proliferation, and, lastly, cells expand to their final shape and size. Although these processes were first described based on mutagenesis approaches in major model systems like Arabidopsis thaliana, further insight into their complexity is best provided by studies of natural variation in organ shape in alternative model systems that sample a broader range of plant form. Weaving together work from both forward and evolutionary genetics, this review focuses on how modification in polarity establishment, cell proliferation and cell expansion drives modifications in the fundamental lateral organ developmental program to create diversity in shape.
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Affiliation(s)
- Cristina L Walcher-Chevillet
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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Landis JB, Ventura KL, Soltis DE, Soltis PS, Oppenheimer DG. Optical sectioning and 3D reconstructions as an alternative to scanning electron microscopy for analysis of cell shape. APPLICATIONS IN PLANT SCIENCES 2015; 3:apps1400112. [PMID: 25909040 PMCID: PMC4406833 DOI: 10.3732/apps.1400112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/21/2015] [Indexed: 05/08/2023]
Abstract
PREMISE OF THE STUDY Visualizing flower epidermal cells is often desirable for investigating the interaction between flowers and their pollinators, in addition to the broader range of ecological interactions in which flowers are involved. We developed a protocol for visualizing petal epidermal cells without the limitations of the commonly used method of scanning electron microscopy (SEM). METHODS Flower material was collected and fixed in glutaraldehyde, followed by dehydration in an ethanol series. Flowers were dissected to collect petals, and subjected to a Histo-Clear series to remove the cuticle. Material was then stained with aniline blue, mounted on microscope slides, and imaged using a compound fluorescence microscope to obtain optical sections that were reconstructed into a 3D image. RESULTS This optical sectioning method yielded high-quality images of the petal epidermal cells with virtually no damage to cells. Flowers were processed in larger batches than are possible using common SEM methods. Also, flower size was not a limiting factor as often observed in SEM studies. Flowers up to 5 cm in length were processed and mounted for visualization. CONCLUSIONS This method requires no special equipment for sample preparation prior to imaging and should be seen as an alternative method to SEM.
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Affiliation(s)
- Jacob B. Landis
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, Florida 32611 USA
- Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida 32611 USA
- Author for correspondence:
| | - Kayla L. Ventura
- Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida 32611 USA
| | - Douglas E. Soltis
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, Florida 32611 USA
- Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida 32611 USA
| | - Pamela S. Soltis
- Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida 32611 USA
| | - David G. Oppenheimer
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, Florida 32611 USA
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48
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Yant L, Collani S, Puzey J, Levy C, Kramer EM. Molecular basis for three-dimensional elaboration of the Aquilegia petal spur. Proc Biol Sci 2015; 282:20142778. [PMID: 25673682 PMCID: PMC4345449 DOI: 10.1098/rspb.2014.2778] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/13/2015] [Indexed: 01/12/2023] Open
Abstract
By enforcing specific pollinator interactions, Aquilegia petal nectar spurs maintain reproductive isolation between species. Spur development is the result of three-dimensional elaboration from a comparatively two-dimensional primordium. Initiated by localized, oriented cell divisions surrounding the incipient nectary, this process creates a pouch that is extended by anisotropic cell elongation. We hypothesized that the development of this evolutionary novelty could be promoted by non-mutually exclusive factors, including (i) prolonged, KNOX-dependent cell fate indeterminacy, (ii) localized organ sculpting and/or (iii) redeployment of hormone-signalling modules. Using cell division markers to guide transcriptome analysis of microdissected spur tissue, we present candidate mechanisms underlying spur outgrowth. We see dynamic expression of factors controlling cell proliferation and hormone signalling, but no evidence of contribution from indeterminacy factors. Transcriptome dynamics point to a novel recruitment event in which auxin-related factors that normally function at the organ margin were co-opted to this central structure. Functional perturbation of the transition between cell division and expansion reveals an unexpected asymmetric component of spur development. These findings indicate that the production of this three-dimensional form is an example of organ sculpting via localized cell division with novel contributions from hormone signalling, rather than a product of prolonged indeterminacy.
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Affiliation(s)
- Levi Yant
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Silvio Collani
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Joshua Puzey
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Clara Levy
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
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Mack JLK, Davis AR. The relationship between cell division and elongation during development of the nectar-yielding petal spur in Centranthus ruber (Valerianaceae). ANNALS OF BOTANY 2015; 115:641-9. [PMID: 25725007 PMCID: PMC4343294 DOI: 10.1093/aob/mcu261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND AIMS Floral spurs are hollow, tubular outgrowths that typically conceal nectar. By their involvement in specialized pollinator interactions, spurs have ecological and evolutionary significance, often leading to speciation. Despite their importance and diversity in shape and size among angiosperm taxa, detailed investigations of the mechanism of spur development have been conducted only recently. METHODS Initiation and growth of the nectar-yielding petal spur of Centranthus ruber 'Snowcloud' was investigated throughout seven stages, based on bud size and developmental events. The determination of the frequency of cell division, quantified for the first time in spurs, was conducted by confocal microscopy following 4',6-diamidino-2-phenylindole (DAPI) staining of mitotic figures. Moreover, using scanning electron microscospy of the outer petal spur surface unobstructed by trichomes, morphometry of epidermal cells was determined throughout development in order to understand the ontogeny of this elongate, hollow tube. KEY RESULTS Spur growth from the corolla base initially included diffuse cell divisions identified among epidermal cells as the spur progressed through its early stages. However, cell divisions clearly diminished before a petal spur attained 30 % of its final length of 4·5 mm. Thereafter until anthesis, elongation of individual cells was primarily responsible for the spur's own extension. Consequently, a prolonged period of anisotropy, wherein epidermal cells elongated almost uniformly in all regions along the petal spur's longitudinal axis, contributed principally to the spur's mature length. CONCLUSIONS This research demonstrates that anisotropic growth of epidermal cells - in the same orientation as spur elongation - chiefly explains petal spur extension in C. ruber. Representing the inaugural investigation of the cellular basis for spur ontogeny within the Euasterids II clade, this study complements the patterns in Aquilegia species (order Ranunculales, Eudicots) and Linaria vulgaris (order Lamiales, Euasterids I), thereby suggesting the existence of a common underlying mechanism for petal spur ontogeny in disparate dicot lineages.
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Affiliation(s)
- Jaimie-Lee K Mack
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Arthur R Davis
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
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Landis JB, O'Toole RD, Ventura KL, Gitzendanner MA, Oppenheimer DG, Soltis DE, Soltis PS. The Phenotypic and Genetic Underpinnings of Flower Size in Polemoniaceae. FRONTIERS IN PLANT SCIENCE 2015; 6:1144. [PMID: 26779209 PMCID: PMC4700140 DOI: 10.3389/fpls.2015.01144] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/02/2015] [Indexed: 05/08/2023]
Abstract
Corolla length is a labile flower feature and has strong implications for pollinator success. However, the phenotypic and genetic bases of corolla elongation are not well known, largely due to a lack of good candidate genes for potential genetic exploration and functional work. We investigate both the cellular phenotypic differences in corolla length, as well as the genetic control of this trait, in Saltugilia (Polemoniaceae). Taxa in this clade exhibit a large range of flower sizes and differ dramatically in pollinator guilds. Flowers of each species were collected from multiple individuals during four stages of flower development to ascertain if cell number or cell size is more important in determining flower size. In Saltugilia, increased flower size during development appears to be driven more by cell size than cell number. Differences in flower size between species are governed by both cell size and cell number, with the large-flowered S. splendens subsp. grantii having nearly twice as many cells as the small-flowered species. Fully mature flowers of all taxa contain jigsaw cells similar to cells seen in sepals and leaves; however, these cells are not typically found in the developing flowers of most species. The proportion of this cell type in mature flowers appears to have substantial implications, comprising 17-68% of the overall flower size. To identify candidate genes responsible for differences in cell area and cell type, transcriptomes were generated for two individuals of the species with the smallest (S. australis) and largest (S. splendens subsp. grantii) flowers across the same four developmental stages visualized with confocal microscopy. Analyses identified genes associated with cell wall formation that are up-regulated in the mature flower stage compared to mid-stage flowers (75% of mature size). This developmental change is associated with the origin of jigsaw cells in the corolla tube of mature flowers. Further comparisons between mature flowers in the two species revealed 354 transcripts that are up-regulated in the large-flowered S. splendens subsp. grantii compared to the small-flowered S. australis. These results are likely broadly applicable to Polemoniaceae, a clade of nearly 400 species, with extensive variation in floral form and shape.
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Affiliation(s)
- Jacob B. Landis
- Department of Biology, University of FloridaGainesville, FL, USA
- Florida Museum of Natural History, University of FloridaGainesville, FL, USA
- *Correspondence: Jacob B. Landis
| | - Rebecca D. O'Toole
- Florida Museum of Natural History, University of FloridaGainesville, FL, USA
| | - Kayla L. Ventura
- Florida Museum of Natural History, University of FloridaGainesville, FL, USA
| | | | - David G. Oppenheimer
- Department of Biology, University of FloridaGainesville, FL, USA
- Genetics Institute, University of FloridaGainesville, FL, USA
- Plant Molecular and Cellular Biology Graduate Program, University of FloridaGainesville, FL, USA
| | - Douglas E. Soltis
- Department of Biology, University of FloridaGainesville, FL, USA
- Florida Museum of Natural History, University of FloridaGainesville, FL, USA
- Genetics Institute, University of FloridaGainesville, FL, USA
- Plant Molecular and Cellular Biology Graduate Program, University of FloridaGainesville, FL, USA
| | - Pamela S. Soltis
- Florida Museum of Natural History, University of FloridaGainesville, FL, USA
- Genetics Institute, University of FloridaGainesville, FL, USA
- Plant Molecular and Cellular Biology Graduate Program, University of FloridaGainesville, FL, USA
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