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Gurung V, Muñoz-Gómez S, Jones DS. Putting heads together: Developmental genetics of the Asteraceae capitulum. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102589. [PMID: 38955094 DOI: 10.1016/j.pbi.2024.102589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/17/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Inflorescence architecture is highly variable across plant lineages yet is critical for facilitating reproductive success. The capitulum-type inflorescence of the Asteraceae is marked as a key morphological innovation that preceded the family's diversification and expansion. Despite its evolutionary significance, our understanding of capitulum development and evolution is limited. This review highlights our current perspective on capitulum evolution through the lens of both its molecular and developmental underpinnings. We attempt to summarize our understanding of the capitulum by focusing on two key characteristics: patterning (arrangement of florets on a capitulum) and floret identity specification. Note that these two features are interconnected such that the identity of florets depends on their position along the inflorescence axis. Phytohormones such as auxin seemingly determine both pattern progression and floret identity specification through unknown mechanisms. Floret morphology in a head is controlled by differential expression of floral symmetry genes regulating floret identity specification. We briefly summarize the applicability of the ABCE quartet model of flower development in regulating the floret organ identity of a capitulum in Asteraceae. Overall, there have been promising advancements in our understanding of capitula; however, comprehensive functional genetic analyses are necessary to fully dissect the molecular pathways and mechanisms involved in capitulum development.
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Affiliation(s)
- Vandana Gurung
- Department of Biological Sciences, Auburn University, 36849, Auburn, AL, USA
| | - Sarita Muñoz-Gómez
- Department of Biological Sciences, Auburn University, 36849, Auburn, AL, USA
| | - Daniel S Jones
- Department of Biological Sciences, Auburn University, 36849, Auburn, AL, USA.
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2
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Owens A, Zhang T, Gu P, Hart J, Stobbs J, Cieslak M, Elomaa P, Prusinkiewicz P. The hidden diversity of vascular patterns in flower heads. THE NEW PHYTOLOGIST 2024; 243:423-439. [PMID: 38361330 DOI: 10.1111/nph.19571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024]
Abstract
Vascular systems are intimately related to the shape and spatial arrangement of the plant organs they support. We investigate the largely unexplored association between spiral phyllotaxis and the vascular system in Asteraceae flower heads. We imaged heads of eight species using synchrotron-based X-ray micro-computed tomography and applied original virtual reality and haptic software to explore head vasculature in three dimensions. We then constructed a computational model to infer a plausible patterning mechanism. The vascular system in the head of the model plant Gerbera hybrida is qualitatively different from those of Bellis perennis and Helianthus annuus, characterized previously. Cirsium vulgare, Craspedia globosa, Echinacea purpurea, Echinops bannaticus, and Tanacetum vulgare represent variants of the Bellis and Helianthus systems. In each species, the layout of the main strands is stereotypical, but details vary. The observed vascular patterns can be generated by a common computational model with different parameter values. In spite of the observed differences of vascular systems in heads, they may be produced by a conserved mechanism. The diversity and irregularities of vasculature stand in contrast with the relative uniformity and regularity of phyllotactic patterns, confirming that phyllotaxis in heads is not driven by the vasculature.
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Affiliation(s)
- Andrew Owens
- Department of Computer Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Teng Zhang
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, Helsinki, 00014, Finland
| | - Philmo Gu
- Department of Computer Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Jeremy Hart
- Department of Computer Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Jarvis Stobbs
- Canadian Light Source Inc., 44 Innovation Blvd, Saskatoon, SK, S7N 2V3, Canada
| | - Mikolaj Cieslak
- Department of Computer Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Paula Elomaa
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, Helsinki, 00014, Finland
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Zhang G, Yang J, Zhang C, Jiao B, Panero JL, Cai J, Zhang ZR, Gao LM, Gao T, Ma H. Nuclear phylogenomics of Asteraceae with increased sampling provides new insights into convergent morphological and molecular evolution. PLANT COMMUNICATIONS 2024; 5:100851. [PMID: 38409784 PMCID: PMC11211554 DOI: 10.1016/j.xplc.2024.100851] [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: 07/29/2023] [Revised: 01/22/2024] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
Convergent morphological evolution is widespread in flowering plants, and understanding this phenomenon relies on well-resolved phylogenies. Nuclear phylogenetic reconstruction using transcriptome datasets has been successful in various angiosperm groups, but it is limited to taxa with available fresh materials. Asteraceae, which are one of the two largest angiosperm families and are important for both ecosystems and human livelihood, show multiple examples of convergent evolution. Nuclear Asteraceae phylogenies have resolved relationships among most subfamilies and many tribes, but many phylogenetic and evolutionary questions regarding subtribes and genera remain, owing to limited sampling. Here, we increased the sampling for Asteraceae phylogenetic reconstruction using transcriptomes and genome-skimming datasets and produced nuclear phylogenetic trees with 706 species representing two-thirds of recognized subtribes. Ancestral character reconstruction supports multiple convergent evolutionary events in Asteraceae, with gains and losses of bilateral floral symmetry correlated with diversification of some subfamilies and smaller groups, respectively. Presence of the calyx-related pappus may have been especially important for the success of some subtribes and genera. Molecular evolutionary analyses support the likely contribution of duplications of MADS-box and TCP floral regulatory genes to innovations in floral morphology, including capitulum inflorescences and bilaterally symmetric flowers, potentially promoting the diversification of Asteraceae. Subsequent divergences and reductions in CYC2 gene expression are related to the gain and loss of zygomorphic flowers. This phylogenomic work with greater taxon sampling through inclusion of genome-skimming datasets reveals the feasibility of expanded evolutionary analyses using DNA samples for understanding convergent evolution.
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Affiliation(s)
- Guojin Zhang
- College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; Department of Biology, the Huck Institute of the Life Sciences, the Pennsylvania State University, State College, PA 16801, USA; State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Junbo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Caifei Zhang
- Wuhan Botanical Garden and Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
| | - Bohan Jiao
- State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - José L Panero
- Department of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - Jie Cai
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Zhi-Rong Zhang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Lian-Ming Gao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; Lijiang National Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Lijiang, Yunnan 674100, China.
| | - Tiangang Gao
- State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
| | - Hong Ma
- Department of Biology, the Huck Institute of the Life Sciences, the Pennsylvania State University, State College, PA 16801, USA.
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4
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Zhang T, Elomaa P. Development and evolution of the Asteraceae capitulum. THE NEW PHYTOLOGIST 2024; 242:33-48. [PMID: 38361269 DOI: 10.1111/nph.19590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/28/2024] [Indexed: 02/17/2024]
Abstract
Asteraceae represent one of the largest and most diverse families of plants. The evolutionary success of this family has largely been contributed to their unique inflorescences, capitula that mimic solitary flowers but are typically aggregates of multiple florets. Here, we summarize the recent molecular and genetic level studies that have promoted our understanding of the development and evolution of capitula. We focus on new results on patterning of the enlarged meristem resulting in the iconic phyllotactic arrangement of florets in Fibonacci numbers of spirals. We also summarize the current understanding of the genetic networks regulating the characteristic reproductive traits in the family such as floral dimorphism and differentiation of highly specialized floral organs. So far, developmental studies in Asteraceae are still limited to a very narrow selection of model species. Along with the recent advancements in genomics and phylogenomics, Asteraceae and its relatives provide an outstanding model clade for extended evo-devo studies to exploit the morphological diversity and the underlying molecular networks and to translate this knowledge to the breeding of the key crops in the family.
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Affiliation(s)
- Teng Zhang
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, 00014, Helsinki, Finland
| | - Paula Elomaa
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, 00014, Helsinki, Finland
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Baczyński J, Claßen-Bockhoff R. Pseudanthia in angiosperms: a review. ANNALS OF BOTANY 2023; 132:179-202. [PMID: 37478306 PMCID: PMC10583202 DOI: 10.1093/aob/mcad103] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/19/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND Pseudanthia or 'false flowers' are multiflowered units that resemble solitary flowers in form and function. Over the last century the term 'pseudanthium' has been applied to a wide array of morphologically divergent blossoms, ranging from those with easily noticeable florets to derived, reduced units in which individual flowers become almost indistinguishable. Although initially admired mostly by botanists, the diversity and widespread distribution of pseudanthia across angiosperms has already made them a fascinating topic for evolutionary and developmental comparative studies. SCOPE This review synthesizes historical and current concepts on the biology of pseudanthia. Our first aim is to establish a clear, operational definition of pseudanthium and disentangle common terminological misconceptions surrounding that term. Our second aim is to summarize knowledge of the morphological and developmental diversity of pseudanthia and embed it within a modern phylogenetic framework. Lastly, we want to provide a comprehensive overview on the evolution and ecological importance of pseudanthia and outline perspectives for future studies. CONCLUSIONS The understanding of pseudanthia has changed multiple times and reflects three different interpretations of their 'flower-like' qualities: developmental (similarity in structure), figural (similarity in form and function) and phylogenetic (homology between angiosperm flowers and monoecious reproductive shoots in gymnosperms). Here, we propose to narrow the term pseudanthium to multiflowered blossoms resembling zoophilous flowers in form, i.e. in being structurally subdivided in a showy periphery and a reproductive centre. According to this definition, pseudanthia sensu stricto evolved independently in at least 41 angiosperm families. The recurrent acquisition of pseudanthia sensu stricto in all major lineages of flowering plants indicates repeated interactions between developmental constraints (smallness of flowers, meristematic conditions) and selective pressures, such as demands of pollinators and/or environmental conditions.
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Affiliation(s)
- Jakub Baczyński
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
- Department of Plant Biology, Miller Plant Sciences, University of Georgia, Athens, Georgia, USA
| | - Regine Claßen-Bockhoff
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University, Mainz, Germany
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Flower-like meristem conditions and spatial constraints shape architecture of floral pseudanthia in Apioideae. EvoDevo 2022; 13:19. [PMID: 36536450 PMCID: PMC9764545 DOI: 10.1186/s13227-022-00204-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 11/27/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Pseudanthia are multiflowered units that resemble single flowers, frequently by association with pseudocorollas formed by enlarged peripheral florets (ray flowers). Such resemblance is not only superficial, because numerous pseudanthia originate from peculiar reproductive meristems with flower-like characteristics, i.e. floral unit meristems (FUMs). Complex FUM-derived pseudanthia with ray flowers are especially common in Apiaceae, but our knowledge about their patterning is limited. In this paper, we aimed to investigate both the genetic and morphological basis of their development. RESULTS We analysed umbel morphogenesis with SEM in six species representing four clades of Apiaceae subfamily Apioideae with independently acquired floral pseudanthia. Additionally, using in situ hybridization, we investigated expression patterns of LEAFY (LFY), UNUSUAL FLORAL ORGANS (UFO), and CYCLOIDEA (CYC) during umbel development in carrot (Daucus carota subsp. carota). Here, we show that initial differences in size and shape of umbel meristems influence the position of ray flower formation, whereas an interplay between peripheral promotion and spatial constraints in umbellet meristems take part in the establishment of specific patterns of zygomorphy in ray flowers of Apiaceae. This space-dependent patterning results from flower-like morphogenetic traits of the umbel which are also visible at the molecular level. Transcripts of DcLFY are uniformly distributed in the incipient umbel, umbellet and flower meristems, while DcCYC shows divergent expression in central and peripheral florets. CONCLUSIONS Our results indicate that umbels develop from determinate reproductive meristems with flower-like characteristics, which supports their recognition as floral units. The great architectural diversity and complexity of pseudanthia in Apiaceae can be explained by the unique conditions of FUMs-an interplay between expression of regulatory genes, specific spatio-temporal ontogenetic constraints and morphogenetic gradients arising during expansion and repetitive fractionation. Alongside Asteraceae, umbellifers constitute an interesting model for investigation of patterning in complex pseudanthia.
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Shen CZ, Zhang CJ, Chen J, Guo YP. Clarifying Recent Adaptive Diversification of the Chrysanthemum-Group on the Basis of an Updated Multilocus Phylogeny of Subtribe Artemisiinae (Asteraceae: Anthemideae). FRONTIERS IN PLANT SCIENCE 2021; 12:648026. [PMID: 34122473 PMCID: PMC8187803 DOI: 10.3389/fpls.2021.648026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/20/2021] [Indexed: 05/12/2023]
Abstract
Understanding the roles played by geography and ecology in driving species diversification and in the maintenance of species cohesion is the central objective of evolutionary and ecological studies. The multi-phased orogenesis of Qinghai-Tibetan Plateau (QTP) and global climate changes over late-Miocene has profoundly influenced the environments and evolution of organisms in this region and the vast areas of Asia. In this study, we investigate the lineage diversification of Chrysanthemum-group in subtribe Artemisiinae (tribe Anthemideae, Asteraceae) likely under the effects of climate changes during this period. Using DNA sequences of seven low-copy nuclear loci and nrITS and the coalescent analytical methods, a time-calibrated phylogeny of subtribe Artemisiinae was reconstructed with emphasis on Chrysanthemum-group. The monophyletic Chrysanthemum-group was well resolved into two major clades corresponding to Chrysanthemum and Ajania, two genera which can be well identified by capitulum morphology but have been intermingled in previous plastid and ITS trees. Within Chrysanthemum, a later divergence between Ch. indicum-complex and Ch. zawadskii-complex can be recognized. The time frames of these sequential divergences coincide with the late Cenozoic uplift of the Northern QTP and the concomitant climatic heterogeneity between eastern and inland Asia. Reconstruction of historical biogeography suggested the origin of Chrysanthemum-group in Central Asia, followed by eastward migration of Chrysanthemum and in situ diversification of Ajania. Within Chrysanthemum, Ch. indicum-complex and Ch. zawadskii-complex exhibited contemporary distributional division, the former in more southern and the latter in more northern regions. The geographic structure of the three lineages in Chrysanthemum-group have been associated with the niche differentiation, and environmental heterogenization in Asia interior.
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Affiliation(s)
- Chu-Ze Shen
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Chu-Jie Zhang
- School of Life Sciences, Peking University, Beijing, China
| | - Jie Chen
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing, China
| | - Yan-Ping Guo
- School of Life Sciences, Peking University, Beijing, China
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8
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Shen CZ, Chen J, Zhang CJ, Rao GY, Guo YP. Dysfunction of CYC2g is responsible for the evolutionary shift from radiate to disciform flowerheads in the Chrysanthemum group (Asteraceae: Anthemideae). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1024-1038. [PMID: 33638198 DOI: 10.1111/tpj.15216] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/11/2021] [Indexed: 05/26/2023]
Abstract
Evolutionary shifts among radiate, disciform and discoid flowerheads have occurred repeatedly in a number of major lineages across the Asteraceae phylogeny; such transitions may also appear within evolutionarily young groups. Although several studies have demonstrated that CYC2 genes partake in regulating floral morphogenesis in Asteraceae, the evolution of capitulum forms within a recently diverging lineage has remained poorly understood. Here, we study the molecular regulation of the shift from a radiate to a disciform capitulum within the Chrysanthemum group. This is a recently radiating group mainly comprising two genera, Chrysanthemum and Ajania, that are phylogenetically intermingled but distinct in flowerhead morphology: Chrysanthemum spp. with radiate capitula and Ajania spp. with disciform capitula. We found that the morphogenesis of zygomorphy in the marginal floret in Ajania was disrupted soon after floral primordium emergence; CYC2g, one of the CYC2 copies that was expressed prominently in the ray floret of Chrysanthemum was not expressed in flowerheads of Ajania. Weakening the expression of ClCYC2g in Chrysanthemum lavandulifolium led to the gradual transition of a ray flower toward the disc-like form. Molecular evolutionary analyses indicated that the disciform capitulum might have evolved only once, approximately 8 Mya, arising from dysfunction of the CYC2g orthologs. A 20-nt deletion, including a putative TATA-box of the Ajania-type CYC2g promoter, appeared to inhibit the expression of the gene. Considering the divergent habitats of Chrysanthemum and Ajania, we propose that the shift from radiate to disciform capitulum must have been related to changes in pollination strategies under selective pressure.
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Affiliation(s)
- Chu-Ze Shen
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, and College of Life Sciences, Beijing Normal University, Beijing, 100875, China
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Jie Chen
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing, 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing, 401331, China
| | - Chu-Jie Zhang
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Guang-Yuan Rao
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yan-Ping Guo
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, and College of Life Sciences, Beijing Normal University, Beijing, 100875, China
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Zhang T, Elomaa P. Don't be fooled: false flowers in Asteraceae. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101972. [PMID: 33383347 DOI: 10.1016/j.pbi.2020.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/02/2020] [Accepted: 09/27/2020] [Indexed: 06/12/2023]
Abstract
The sunflower or daisy family, Asteraceae, comprises of approximately 10% of all angiosperm species. Their inflorescences form dense flower-like structures, pseudanthia or false flowers that may combine hundreds of individual flowers into a single structure. Recent data suggest that pseudanthia are analogs of single flowers not only morphologically but also at developmental and genetic level, and cannot merely be considered as condensed inflorescences. The large meristem size provides an advantage to study basic principles of patterning as well as inflorescence diversity in this evolutionary successful family. This knowledge has also practical importance in the commercially important crops of the family.
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Affiliation(s)
- Teng Zhang
- Department of Agricultural Sciences, Viikki Plant Science Centre, 00014 University of Helsinki, Finland
| | - Paula Elomaa
- Department of Agricultural Sciences, Viikki Plant Science Centre, 00014 University of Helsinki, Finland.
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10
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Elomaa P. My favourite flowering image: a capitulum of Asteraceae. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:e6496-e6498. [PMID: 28338732 PMCID: PMC6859721 DOI: 10.1093/jxb/erw489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Affiliation(s)
- Paula Elomaa
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Finland
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11
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Li F, Lan W, Zhou Q, Liu B, Chen F, Zhang S, Bao M, Liu G. Reduced Expression of CbUFO Is Associated with the Phenotype of a Flower-Defective Cosmos bipinnatus. Int J Mol Sci 2019; 20:E2503. [PMID: 31117210 PMCID: PMC6566773 DOI: 10.3390/ijms20102503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 12/03/2022] Open
Abstract
LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO) homologous genes have been reported to play key roles in promoting the initiation of floral meristems in raceme- and cyme-type plants. Asteraceae, a large family of plants with more than 23,000 species, has a unique head-like inflorescence termed capitulum. Here, we report a floral defective plant of the garden cosmos named green head (gh), which shows homogeneous inflorescence, indistinguishable inflorescence periphery and center, and the replacement of flower meristems by indeterminate inflorescence meristems, coupled with iterative production of bract-like organs and higher order of inflorescences. A comparison of the LFY- and UFO-like genes (CbFLY and CbUFO) isolated from both the wild-type and gh cosmos revealed that CbUFO may play an important role in inflorescence differentiation into different structures and promotion of flower initiation, and the reduced expression of CbUFO in the gh cosmos could be associated with the phenotypes of the flower-defective plants. Further expression analysis indicated that CbUFO may promote the conversion of inflorescence meristem into floral meristem in early ray flower formation, but does not play a role in its later growth period.
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Affiliation(s)
- Fei Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Wu Lan
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Qin Zhou
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Baojun Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Feng Chen
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Sisi Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
- Landscape plants research department, Wuhan Institute of Landscape Gardening, Wuhan 430081, China.
| | - Manzhu Bao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guofeng Liu
- Guangzhou Institute of Forestry and Landscape Architecture, Guangzhou 510405, China.
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12
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Using integrative taxonomy and multispecies coalescent models for phylogeny reconstruction and species delimitation within the “Nastanthus–Gamocarpha” clade (Calyceraceae). Mol Phylogenet Evol 2019; 130:211-226. [DOI: 10.1016/j.ympev.2018.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 09/28/2018] [Accepted: 10/11/2018] [Indexed: 11/20/2022]
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13
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Spencer V, Kim M. Re“CYC”ling molecular regulators in the evolution and development of flower symmetry. Semin Cell Dev Biol 2018; 79:16-26. [DOI: 10.1016/j.semcdb.2017.08.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/28/2017] [Indexed: 11/27/2022]
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14
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Claßen-Bockhoff R, Arndt M. Flower-like heads from flower-like meristems: pseudanthium development in Davidia involucrata (Nyssaceae). JOURNAL OF PLANT RESEARCH 2018; 131:443-458. [PMID: 29569169 DOI: 10.1007/s10265-018-1029-6] [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: 10/19/2017] [Accepted: 02/23/2018] [Indexed: 06/08/2023]
Abstract
Flower-like inflorescences (pseudanthia) have fascinated botanists for a long time. They are explained as condensed inflorescences implying that the pseudanthium develops from an inflorescence meristem (IM). However, recent developmental studies identified a new form of reproductive meristem, the floral unit meristem (FUM). It differs from IMs by lacking acropetal growth and shares fractionation, expansion and autonomous space filling with flower meristems (FM). The similarity among FUMs and FMs raises the question how far flower-like heads originate from flower-like meristems. In the present paper, pseudanthium development in Davidia involucrata is investigated using scanning electron microscopy. D. involucrata has pincushion-shaped heads composed of densely aggregated, perianthless flowers and associated with two large showy bracts. Early developmental stages show a huge naked FUM. The FMs appear almost simultaneously and lack subtending bracts. With ongoing FUM expansion new space is generated which is immediately used by further FM fractionation. The heads have only staminate flowers or are andromonoecious with staminate and a single perfect flower in oblique position. All FMs lack perianth structures and fractionate a variable number of stamen primordia. The perfect FM is much larger than the staminate FMs and forms a syncarpous gynoecium with inferior ovary. Pseudanthium development in D. involucrata confirms the morphogenetic similarity to FMs as to acropetal growth limitation, meristem expansion and fractionation. It thus should not be interpreted as a condensed inflorescence, but as a flower equivalent. Furthermore as the FUM develops inside a bud, its development is considered to be influenced by mechanical pressure. The oblique position of the perfect flower, the developmental delay of the proximal flowers, and the variable number of stamens which were observed in the pseudanthium development, can be caused by mechanical pressure. Next to the Asteraceae, D. involucrata offers a further example of a pseudanthium originating from a FUM. More knowledge on FUMs is still needed to understand diversification and evolution of flower-like inflorescences.
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Affiliation(s)
- Regine Claßen-Bockhoff
- Institute of Organismic and Molecular Evolution (iomE), Johannes Gutenberg-University Mainz, Anselm Franz von Bentzel-Weg 2, 55099, Mainz, Germany.
| | - Melanie Arndt
- Institute of Organismic and Molecular Evolution (iomE), Johannes Gutenberg-University Mainz, Anselm Franz von Bentzel-Weg 2, 55099, Mainz, Germany
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Elomaa P, Zhao Y, Zhang T. Flower heads in Asteraceae-recruitment of conserved developmental regulators to control the flower-like inflorescence architecture. HORTICULTURE RESEARCH 2018; 5:36. [PMID: 29977572 PMCID: PMC6026493 DOI: 10.1038/s41438-018-0056-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/31/2018] [Accepted: 05/31/2018] [Indexed: 05/03/2023]
Abstract
Inflorescences in the Asteraceae plant family, flower heads, or capitula, mimic single flowers but are highly compressed structures composed of multiple flowers. This transference of a flower-like appearance into an inflorescence level is considered as the key innovation for the rapid tribal radiation of Asteraceae. Recent molecular data indicate that Asteraceae flower heads resemble single flowers not only morphologically but also at molecular level. We summarize this data giving examples of how rewiring of conserved floral regulators have led to evolution of morphological innovations in Asteraceae. Functional diversification of the highly conserved flower meristem identity regulator LEAFY has shown a major role in the evolution of the capitulum architecture. Furthermore, gene duplication and subsequent sub- and neofunctionalization of SEPALLATA- and CYCLOIDEA-like genes in Asteraceae have been shown to contribute to meristem determinacy, as well as flower type differentiation-key traits that specify this large family. Future challenge is to integrate genomic, as well as evolutionary developmental studies in a wider selection of Asteraceae species to understand the detailed gene regulatory networks behind the elaborate inflorescence architecture, and to promote our understanding of how changes in regulatory mechanisms shape development.
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Affiliation(s)
- Paula Elomaa
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014 Helsinki, Finland
| | - Yafei Zhao
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014 Helsinki, Finland
| | - Teng Zhang
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014 Helsinki, Finland
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Bello MA, Cubas P, Álvarez I, Sanjuanbenito G, Fuertes-Aguilar J. Evolution and Expression Patterns of CYC/TB1 Genes in Anacyclus: Phylogenetic Insights for Floral Symmetry Genes in Asteraceae. FRONTIERS IN PLANT SCIENCE 2017; 8:589. [PMID: 28487706 PMCID: PMC5403951 DOI: 10.3389/fpls.2017.00589] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/31/2017] [Indexed: 05/20/2023]
Abstract
Homologs of the CYC/TB1 gene family have been independently recruited many times across the eudicots to control aspects of floral symmetry The family Asteraceae exhibits the largest known diversification in this gene paralog family accompanied by a parallel morphological floral richness in its specialized head-like inflorescence. In Asteraceae, whether or not CYC/TB1 gene floral symmetry function is preserved along organismic and gene lineages is unknown. In this study, we used phylogenetic, structural and expression analyses focused on the highly derived genus Anacyclus (tribe Anthemidae) to address this question. Phylogenetic reconstruction recovered eight main gene lineages present in Asteraceae: two from CYC1, four from CYC2 and two from CYC3-like genes. The species phylogeny was recovered in most of the gene lineages, allowing the delimitation of orthologous sets of CYC/TB1 genes in Asteraceae. Quantitative real-time PCR analysis indicated that in Anacyclus three of the four isolated CYC2 genes are more highly expressed in ray flowers. The expression of the four AcCYC2 genes overlaps in several organs including the ligule of ray flowers, as well as in anthers and ovules throughout development.
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Affiliation(s)
- María A. Bello
- Plant Evolutionary Biology Group, Real Jardín Botánico (CSIC)Madrid, Spain
| | - Pilar Cubas
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, CSIC-Universidad Autónoma de MadridMadrid, Spain
| | - Inés Álvarez
- Plant Evolutionary Biology Group, Real Jardín Botánico (CSIC)Madrid, Spain
| | | | - Javier Fuertes-Aguilar
- Plant Evolutionary Biology Group, Real Jardín Botánico (CSIC)Madrid, Spain
- *Correspondence: Javier Fuertes-Aguilar
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Marcellini S, González F, Sarrazin AF, Pabón-Mora N, Benítez M, Piñeyro-Nelson A, Rezende GL, Maldonado E, Schneider PN, Grizante MB, Da Fonseca RN, Vergara-Silva F, Suaza-Gaviria V, Zumajo-Cardona C, Zattara EE, Casasa S, Suárez-Baron H, Brown FD. Evolutionary Developmental Biology (Evo-Devo) Research in Latin America. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:5-40. [PMID: 27491339 DOI: 10.1002/jez.b.22687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/16/2016] [Accepted: 06/20/2016] [Indexed: 12/29/2022]
Abstract
Famous for its blind cavefish and Darwin's finches, Latin America is home to some of the richest biodiversity hotspots of our planet. The Latin American fauna and flora inspired and captivated naturalists from the nineteenth and twentieth centuries, including such notable pioneers such as Fritz Müller, Florentino Ameghino, and Léon Croizat who made a significant contribution to the study of embryology and evolutionary thinking. But, what are the historical and present contributions of the Latin American scientific community to Evo-Devo? Here, we provide the first comprehensive overview of the Evo-Devo laboratories based in Latin America and describe current lines of research based on endemic species, focusing on body plans and patterning, systematics, physiology, computational modeling approaches, ecology, and domestication. Literature searches reveal that Evo-Devo in Latin America is still in its early days; while showing encouraging indicators of productivity, it has not stabilized yet, because it relies on few and sparsely distributed laboratories. Coping with the rapid changes in national scientific policies and contributing to solve social and health issues specific to each region are among the main challenges faced by Latin American researchers. The 2015 inaugural meeting of the Pan-American Society for Evolutionary Developmental Biology played a pivotal role in bringing together Latin American researchers eager to initiate and consolidate regional and worldwide collaborative networks. Such networks will undoubtedly advance research on the extremely high genetic and phenotypic biodiversity of Latin America, bound to be an almost infinite source of amazement and fascinating findings for the Evo-Devo community.
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Affiliation(s)
- Sylvain Marcellini
- Laboratorio de Desarrollo y Evolución, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Favio González
- Facultad de Ciencias, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Andres F Sarrazin
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | | | - Mariana Benítez
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Alma Piñeyro-Nelson
- Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana, Xochimilco, Ciudad de México, México
| | - Gustavo L Rezende
- Universidade Estadual do Norte Fluminense, CBB, LQFPP, Campos dos Goytacazes, RJ, Brazil
| | - Ernesto Maldonado
- EvoDevo Lab, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | | | | | - Rodrigo Nunes Da Fonseca
- Núcleo em Ecologia e Desenvolvimento SócioAmbiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro, Macae, RJ, Brazil
| | | | | | | | | | - Sofia Casasa
- Department of Biology, Indiana University, Bloomington, IN, USA
| | | | - Federico D Brown
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil
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Panero JL, Crozier BS. Macroevolutionary dynamics in the early diversification of Asteraceae. Mol Phylogenet Evol 2016; 99:116-132. [DOI: 10.1016/j.ympev.2016.03.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 02/25/2016] [Accepted: 03/07/2016] [Indexed: 12/29/2022]
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Katinas L, Hernández MP, Arambarri AM, Funk VA. The origin of the bifurcating style in Asteraceae (Compositae). ANNALS OF BOTANY 2016; 117:1009-21. [PMID: 27098086 PMCID: PMC4866318 DOI: 10.1093/aob/mcw033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 12/22/2015] [Accepted: 01/08/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND AND AIMS The plant family Asteraceae (Compositae) exhibits remarkable morphological variation in the styles of its members. Lack of studies on the styles of the sister families to Asteraceae, Goodeniaceae and Calyceraceae, obscures our understanding of the origin and evolution of this reproductive feature in these groups. The aim of this work was to perform a comparative study of style morphology and to discuss the relevance of important features in the evolution of Asteraceae and its sister families. METHODS The histochemistry, venation and general morphology of the styles of members of Goodeniaceae, Calyceraceae and early branching lineages of Asteraceae were analysed and put in a phylogenetic framework to discuss the relevance of style features in the evolution of these families. KEY RESULTS The location of lipophilic substances allowed differentiation of receptive from non-receptive style papillae, and the style venation in Goodeniaceae and Calyceraceae proved to be distinctive. There were several stages of style evolution from Goodeniaceae to Asteraceae involving connation and elongation of veins, development of bilobation from an initially cup-shaped style, and a redistribution of the receptive and non-receptive papillae. CONCLUSIONS These developments resulted in bifurcation in the styles of Asteraceae, with each branch face having a different function, and it is suggested here as a mechanism that promoted outcrossing, which in turn led to the great diversification in the family.
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Affiliation(s)
- Liliana Katinas
- División Plantas Vasculares, Museo de La Plata, La Plata, Argentina Laboratorio de Morfología Comparada de Espermatófitas (LAMCE), Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, La Plata, Argentina
| | - Marcelo P Hernández
- Laboratorio de Morfología Comparada de Espermatófitas (LAMCE), Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, La Plata, Argentina
| | - Ana M Arambarri
- Laboratorio de Morfología Comparada de Espermatófitas (LAMCE), Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, La Plata, Argentina
| | - Vicki A Funk
- Department of Botany, NMNH, Smithsonian Institution, Washington D.C., USA
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Antonio CNS, Elnatan BDS, Marcos FABGR, Maria RJRA, Paulo NB, H eacute lcio SDSRP, Selene MDM, Raquel ODSF, Carolina SDPC. Cytotoxicity, antifungal and antioxidant activities of the essential oil from Eupatorium ballotifolium Kunth (Asteraceae). ACTA ACUST UNITED AC 2016. [DOI: 10.5897/ajpp2016.4537] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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21
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Antonio CNS, Elnatan BDS, Raquel ODSF. A review on antimicrobial potential of species of the genus Vernonia (Asteraceae). ACTA ACUST UNITED AC 2015. [DOI: 10.5897/jmpr2015.5868] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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22
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Resolution of deep nodes yields an improved backbone phylogeny and a new basal lineage to study early evolution of Asteraceae. Mol Phylogenet Evol 2014; 80:43-53. [DOI: 10.1016/j.ympev.2014.07.012] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/16/2014] [Accepted: 07/18/2014] [Indexed: 12/30/2022]
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Claßen-Bockhoff R, Bull-Hereñu K. Towards an ontogenetic understanding of inflorescence diversity. ANNALS OF BOTANY 2013; 112:1523-42. [PMID: 23445936 PMCID: PMC3828942 DOI: 10.1093/aob/mct009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 12/12/2012] [Indexed: 05/20/2023]
Abstract
BACKGROUNDS AND AIMS Conceptual and terminological conflicts in inflorescence morphology indicate a lack of understanding of the phenotypic diversity of inflorescences. In this study, an ontogeny-based inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms. METHODS Species from 105 genera in 52 angiosperm families are investigated to identify their specific reproductive meristems and developmental pathways. Based on these studies, long-term experience with inflorescences and literature research, a conceptual framework for the understanding of inflorescences is presented. KEY RESULTS Ontogeny reveals that reproductive systems traditionally called inflorescences fall into three groups, i.e. 'flowering shoot systems' (FSS), 'inflorescences' sensu stricto and 'floral units' (FUs). Our concept is, first, based on the identification of reproductive meristem position and developmental potential. The FSS, defined as a seasonal growth unit, is used as a reference framework. As the FSS is a leafy shoot system bearing reproductive units, foliage and flowering sequence play an important role. Second, the identification of two different flower-producing meristems is essential. While 'inflorescence meristems' (IMs) share acropetal primordia production with vegetative meristems, 'floral unit meristems' (FUMs) resemble flower meristems in being indeterminate. IMs produce the basic inflorescence types, i.e. compound and simple racemes, panicles and botryoids. FUMs give rise to dense, often flower-like units (e.g. heads). They occur solitarily at the FSS or occupy flower positions in inflorescences, rendering the latter thyrses in the case of cymose branching. CONCLUSIONS The ontogenetic concept differs from all existing inflorescence concepts in being based on meristems and developmental processes. It includes clear terms and allows homology statements. Transitional forms are an explicit part of the concept, illustrating the ontogenetic potential for character transformation in evolution.
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Affiliation(s)
- Regine Claßen-Bockhoff
- Institut für Spezielle Botanik und Botanischer Garten, Johannes-Gutenberg Universität Mainz, Germany
- For correspondence. E-mail
| | - Kester Bull-Hereñu
- Escuela de Pedagogica en Biología y Ciencias, Universidad Central de Chile, Santiago de Chile, Chile
- Departamento de Ecologia Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
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Bello MA, Álvarez I, Torices R, Fuertes-Aguilar J. Floral development and evolution of capitulum structure in Anacyclus (Anthemideae, Asteraceae). ANNALS OF BOTANY 2013; 112:1597-612. [PMID: 23287557 PMCID: PMC3828941 DOI: 10.1093/aob/mcs301] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Most of the diversity in the pseudanthia of Asteraceae is based on the differential symmetry and sexuality of its flowers. In Anacyclus, where there are (1) homogamous capitula, with bisexual, mainly actinomorphic and pentamerous flowers; and (2) heterogamous capitula, with peripheral zygomorphic, trimerous and long-/short-rayed female flowers, the floral ontogeny was investigated to infer their origin. METHODS Floral morphology and ontogeny were studied using scanning electron microscope and light microscope techniques. KEY RESULTS Disc flowers, subtended by paleae, initiate acropetally. Perianth and androecium initiation is unidirectional/simultaneous. Late zygomorphy occurs by enlargement of the adaxial perianth lobes. In contrast, ray flowers, subtended by involucral bracts, initiate after the proximal disc buds, breaking the inflorescence acropetal pattern. Early zygomorphy is manifested through the fusion of the lateral and abaxial perianth lobes and the arrest of the adaxials. We report atypical phenotypes with peripheral 'trumpet' flowers from natural populations. The peripheral 'trumpet' buds initiate after disc flowers, but maintain an actinomorphic perianth. All phenotypes are compared and interpreted in the context of alternative scenarios for the origin of the capitulum and the perianth identity. CONCLUSIONS Homogamous inflorescences display a uniform floral morphology and development, whereas the peripheral buds in heterogamous capitula display remarkable plasticity. Disc and ray flowers follow different floral developmental pathways. Peripheral zygomorphic flowers initiate after the proximal actinomorphic disc flowers, behaving as lateral independent units of the pseudanthial disc from inception. The perianth and the androecium are the most variable whorls across the different types of flowers, but their changes are not correlated. Lack of homology between hypanthial appendages and a calyx, and the perianth double-sided structure are discussed for Anacyclus together with potential causes of its ray flower plasticity.
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Affiliation(s)
- M. Angélica Bello
- Real Jardín Botánico, RJB-CSIC, Plaza de Murillo 2, 28014 Madrid, Spain
- For correspondence. E-mail
| | - Inés Álvarez
- Real Jardín Botánico, RJB-CSIC, Plaza de Murillo 2, 28014 Madrid, Spain
| | - Rubén Torices
- Centro de Ecologia Funcional, Universidade de Coimbra, 3001-455 Coimbra, Portugal
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Kirchoff BK, Claßen-Bockhoff R. Inflorescences: concepts, function, development and evolution. ANNALS OF BOTANY 2013; 112:1471-6. [PMID: 24383103 PMCID: PMC3828949 DOI: 10.1093/aob/mct267] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/08/2013] [Indexed: 05/25/2023]
Abstract
BACKGROUND Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruits prior to dispersal, and facilitate effective fruit and seed dispersal. From a structural point of view, inflorescences have played important roles in systematic and phylogenetic studies. As functional units they facilitate reproduction, and are largely shaped by natural selection. SCOPE The papers in this Special Issue bridge the gap between structural and functional approaches to inflorescence evolution. They include a literature review of inflorescence function, an experimental study of inflorescences as essential contributors to the display of flowers, and two papers that present new methods and concepts for understanding inflorescence diversity and for dealing with terminological problems. The transient model of inflorescence development is evaluated in an ontogenetic study, and partially supported. Four papers present morphological and ontogenetic studies of inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister's Rule and inhibitory fields to predict inflorescence structure. In the final two papers, Bayesian and Monte-Carlo methods are used to elucidate inflorescence evolution in the Panicoid grasses, and a candidate gene approach is used in an attempt to understand the evolutionary genetics of inflorescence evolution in the genus Cornus (Cornaceae). Taken as a whole, the papers in this issue provide a glimpse of contemporary approaches to the study of the structure, development, and evolution of inflorescences, and suggest fruitful new directions for research.
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Affiliation(s)
- Bruce K. Kirchoff
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
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Harder LD, Prusinkiewicz P. The interplay between inflorescence development and function as the crucible of architectural diversity. ANNALS OF BOTANY 2013; 112:1477-93. [PMID: 23243190 PMCID: PMC3828939 DOI: 10.1093/aob/mcs252] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
BACKGROUND Most angiosperms present flowers in inflorescences, which play roles in reproduction, primarily related to pollination, beyond those served by individual flowers alone. An inflorescence's overall reproductive contribution depends primarily on the three-dimensional arrangement of the floral canopy and its dynamics during its flowering period. These features depend in turn on characteristics of the underlying branching structure (scaffold) that supports and supplies water and nutrients to the floral canopy. This scaffold is produced by developmental algorithms that are genetically specified and hormonally mediated. Thus, the extensive inflorescence diversity evident among angiosperms evolves through changes in the developmental programmes that specify scaffold characteristics, which in turn modify canopy features that promote reproductive performance in a particular pollination and mating environment. Nevertheless, developmental and ecological aspects of inflorescences have typically been studied independently, limiting comprehensive understanding of the relations between inflorescence form, reproductive function, and evolution. SCOPE This review fosters an integrated perspective on inflorescences by summarizing aspects of their development and pollination function that enable and guide inflorescence evolution and diversification. CONCLUSIONS The architecture of flowering inflorescences comprises three related components: topology (branching patterns, flower number), geometry (phyllotaxis, internode and pedicel lengths, three-dimensional flower arrangement) and phenology (flower opening rate and longevity, dichogamy). Genetic and developmental evidence reveals that these components are largely subject to quantitative control. Consequently, inflorescence evolution proceeds along a multidimensional continuum. Nevertheless, some combinations of topology, geometry and phenology are represented more commonly than others, because they serve reproductive function particularly effectively. For wind-pollinated species, these combinations often represent compromise solutions to the conflicting physical influences on pollen removal, transport and deposition. For animal-pollinated species, dominant selective influences include the conflicting benefits of large displays for attracting pollinators and of small displays for limiting among-flower self-pollination. The variety of architectural components that comprise inflorescences enable diverse resolutions of these conflicts.
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Affiliation(s)
- Lawrence D. Harder
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- For correspondence. Email
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Scholz A, Rabaey D, Stein A, Cochard H, Smets E, Jansen S. The evolution and function of vessel and pit characters with respect to cavitation resistance across 10 Prunus species. TREE PHYSIOLOGY 2013; 33:684-694. [PMID: 23933827 DOI: 10.1093/treephys/tpt050] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Various structure-function relationships regarding drought-induced cavitation resistance of secondary xylem have been postulated. These hypotheses were tested on wood of 10 Prunus species showing a range in P50 (i.e., the pressure corresponding to 50% loss of hydraulic conductivity) from -3.54 to -6.27 MPa. Hydraulically relevant wood characters were quantified using light and electron microscopy. A phylogenetic tree was constructed to investigate evolutionary correlations using a phylogenetically independent contrast (PIC) analysis. Vessel-grouping characters were found to be most informative in explaining interspecific variation in P50, with cavitation-resistant species showing more solitary vessels than less resistant species. Co-evolution between vessel-grouping indices and P50 was reported. P50 was weakly correlated with the shape of the intervessel pit aperture, but not with the total intervessel pit membrane area per vessel. A negative correlation was found between P50 and intervessel pit membrane thickness, but this relationship was not supported by the PIC analysis. Cavitation resistance has co-evolved with vessel grouping within Prunus and was mainly influenced by the spatial distribution of the vessel network.
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Affiliation(s)
- Alexander Scholz
- Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
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Naghiloo S, Dadpour MR, Gohari G, Endress PK. Comparative study of inflorescence development in Oleaceae. AMERICAN JOURNAL OF BOTANY 2013; 100:647-663. [PMID: 23482481 DOI: 10.3732/ajb.1200171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY Investigations of inflorescence architecture offer insight into the evolution of an astounding array of reproductive shoot systems in the angiosperms, as well as the potential to genetically manipulate these branching patterns to improve crop yield and enhance the aesthetics of horticultural species. The diversity of inflorescences in the economically important family Oleaceae was studied from a comparative developmental point of view for the first time, based on species of seven genera (Chionanthus, Fontanesia, Fraxinus, Jasminum, Ligustrum, Olea, Syringa). METHODS Series of developmental stages of chemically fixed inflorescences were studied with epi-illumination light microscopy. KEY RESULTS All taxa studied have inflorescences with terminal flowers. The inflorescences are mostly panicles, but in some cases thyrsoids or compound botryoids. Phyllotaxis of the flower-subtending bracts is mostly decussate, rarely tricussate (Fraxinus) or spiral (Jasminum). Accessory flowers or accessory inflorescences, almost unknown in Oleaceae as yet, were found in two genera. In Syringa, common bract-flower primordia are formed by a delay in early bract development compared to flower development. Such a delay is also expressed by the loss of bracts in the distal part of inflorescence branches in Syringa and Chionanthus. CONCLUSIONS Significant variation in branching pattern and phyllotaxy was observed among the studied species of Oleaceae. The suppression of bracts and formation of accessory flowers were found as special features of inflorescence ontogeny. The occurrence of accessory flowers and accessory partial inflorescences is interesting from the point of view of dense and flower-rich inflorescences in ornamental species.
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Affiliation(s)
- Somayeh Naghiloo
- Department of Plant Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
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