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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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2
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Kellenberger RT, Glover BJ. The evolution of flower colour. Curr Biol 2023; 33:R484-R488. [PMID: 37279680 DOI: 10.1016/j.cub.2023.01.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Flowers are the most commonly seen colourful elements of the natural world, and in this primer we explain the evolution of their spectacular range of colours. To understand flower colour, we first explain what colour is and how a flower can have different colours in the eyes of different observers. We briefly introduce the molecular and biochemical basis of flower colour, which is primarily based on well-characterised pigment synthesis pathways. We then consider the evolution of flower colour over four timescales - its origin and deep evolution, its macroevolution, its microevolution and finally, the recent effects of human behaviour on flower colour and its evolution. Because flower colour is so evolutionarily labile, and at the same time so striking to the human eye, it is an exciting subject for current and future research efforts.
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Affiliation(s)
- Roman T Kellenberger
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, UK.
| | - Beverley J Glover
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, UK.
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Rosas-Reinhold I, Piñeyro-Nelson A, Rosas U, Arias S. Blurring the Boundaries between a Branch and a Flower: Potential Developmental Venues in CACTACEAE. PLANTS (BASEL, SWITZERLAND) 2021; 10:1134. [PMID: 34204904 PMCID: PMC8228900 DOI: 10.3390/plants10061134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 11/16/2022]
Abstract
Flowers are defined as short shoots that carry reproductive organs. In Cactaceae, this term acquires another meaning, since the flower is interpreted as a branch with a perianth at the tip, with all reproductive organs embedded within the branch, thus giving way to a structure that has been called a "flower shoot". These organs have long attracted the attention of botanists and cactologists; however, the understanding of the morphogenetic processes during the development of these structures is far from clear. In this review, we present and discuss some classic flower concepts used to define floral structures in Cactaceae in the context of current advances in flower developmental genetics and evolution. Finally, we propose several hypotheses to explain the origin of these floral shoot structures in cacti, and we suggest future research approaches and methods that could be used to fill the gaps in our knowledge regarding the ontogenetic origin of the "flower" in the cactus family.
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Affiliation(s)
- Isaura Rosas-Reinhold
- Instituto de Biología, Jardín Botánico, Universidad Nacional Autónoma de México, Ciudad de México C.P.04510, Mexico; (I.R.-R.); (U.R.)
- Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, A. P. 70-153, Ciudad de México C.P.04510, Mexico
| | - Alma Piñeyro-Nelson
- Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana-Xochimilco, Ciudad de México C.P.04510, Mexico;
- Centro de Ciencias de la Complejidad (C3), Universidad Nacional Autónoma de México, Ciudad de México C.P.04960, Mexico
| | - Ulises Rosas
- Instituto de Biología, Jardín Botánico, Universidad Nacional Autónoma de México, Ciudad de México C.P.04510, Mexico; (I.R.-R.); (U.R.)
| | - Salvador Arias
- Instituto de Biología, Jardín Botánico, Universidad Nacional Autónoma de México, Ciudad de México C.P.04510, Mexico; (I.R.-R.); (U.R.)
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Rudall PJ. Colourful cones: how did flower colour first evolve? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:759-767. [PMID: 31714579 DOI: 10.1093/jxb/erz479] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/14/2019] [Indexed: 05/09/2023]
Abstract
Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.
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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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Sokoloff DD, Remizowa MV, Bateman RM, Rudall PJ. Was the ancestral angiosperm flower whorled throughout? AMERICAN JOURNAL OF BOTANY 2018. [PMID: 29532932 DOI: 10.1002/ajb2.1003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Affiliation(s)
- Dmitry D Sokoloff
- Biological Faculty, M.V. Lomonosov Moscow State University, 119234, Moscow, Russia
| | - Margarita V Remizowa
- Biological Faculty, M.V. Lomonosov Moscow State University, 119234, Moscow, Russia
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Moyroud E, Monniaux M, Thévenon E, Dumas R, Scutt CP, Frohlich MW, Parcy F. A link between LEAFY and B-gene homologues in Welwitschia mirabilis sheds light on ancestral mechanisms prefiguring floral development. THE NEW PHYTOLOGIST 2017; 216:469-481. [PMID: 28233912 DOI: 10.1111/nph.14483] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 01/05/2017] [Indexed: 05/26/2023]
Abstract
Flowering plants evolved from an unidentified gymnosperm ancestor. Comparison of the mechanisms controlling development in angiosperm flowers and gymnosperm cones may help to elucidate the mysterious origin of the flower. We combined gene expression studies with protein behaviour characterization in Welwitschia mirabilis to test whether the known regulatory links between LEAFY and its MADS-box gene targets, central to flower development, might also contribute to gymnosperm reproductive development. We found that WelLFY, one of two LEAFY-like genes in Welwitschia, could be an upstream regulator of the MADS-box genes APETALA3/PISTILLATA-like (B-genes). We demonstrated that, even though their DNA-binding domains are extremely similar, WelLFY and its paralogue WelNDLY exhibit distinct DNA-binding specificities, and that, unlike WelNDLY, WelLFY shares with its angiosperm orthologue the capacity to bind promoters of Welwitschia B-genes. Finally, we identified several cis-elements mediating these interactions in Welwitschia and obtained evidence that the link between LFY homologues and B-genes is also conserved in two other gymnosperms, Pinus and Picea. Although functional approaches to investigate cone development in gymnosperms are limited, our state-of-the-art biophysical techniques, coupled with expression studies, provide evidence that crucial links, central to the control of floral development, may already have existed before the appearance of flowers.
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Affiliation(s)
- Edwige Moyroud
- LPCV, CEA, CNRS, INRA, Université Grenoble-Alpes, BIG, 38000, Grenoble, France
| | - Marie Monniaux
- LPCV, CEA, CNRS, INRA, Université Grenoble-Alpes, BIG, 38000, Grenoble, France
| | - Emmanuel Thévenon
- LPCV, CEA, CNRS, INRA, Université Grenoble-Alpes, BIG, 38000, Grenoble, France
| | - Renaud Dumas
- LPCV, CEA, CNRS, INRA, Université Grenoble-Alpes, BIG, 38000, Grenoble, France
| | - Charles P Scutt
- Laboratoire de Reproduction et Développement des Plantes, UMR5667, CNRS, INRA, Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon Cedex 07, France
| | - Michael W Frohlich
- Laboratoire de Reproduction et Développement des Plantes, UMR5667, CNRS, INRA, Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon Cedex 07, France
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK
| | - François Parcy
- LPCV, CEA, CNRS, INRA, Université Grenoble-Alpes, BIG, 38000, Grenoble, France
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8
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Herendeen PS, Friis EM, Pedersen KR, Crane PR. Palaeobotanical redux: revisiting the age of the angiosperms. NATURE PLANTS 2017; 3:17015. [PMID: 28260783 DOI: 10.1038/nplants.2017.15] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/24/2017] [Indexed: 06/06/2023]
Abstract
Angiosperms (flowering plants) are the most diverse of all major lineages of land plants and the dominant autotrophs in most terrestrial ecosystems. Their evolutionary and ecological appearance is therefore of considerable interest and has significant implications for understanding patterns of diversification in other lineages, including insects and other animals. More than half a century ago, influential reviews showed that while angiosperms are richly represented in sediments of Late Cretaceous and younger ages, there are no reliable records of angiosperms from pre-Cretaceous rocks. The extensive new macrofossil, mesofossil, and microfossil data that have accumulated since have confirmed and reinforced this pattern. Recently, however, molecular dating methods have raised the possibility that angiosperms may have existed much earlier, and there have been scattered reports of putative angiosperms from Triassic and Jurassic rocks. Critical assessment of these reports shows that, so far, none provide unequivocal evidence of pre-Cretaceous angiosperms. Angiosperms may ultimately be recognized from Jurassic or earlier rocks, but credible palaeobotanical evidence will require unambiguous documentation of the diagnostic structural features that separate angiosperms from other groups of extant and extinct seed plants.
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Affiliation(s)
| | - Else Marie Friis
- Department of Palaeobiology, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden
| | | | - Peter R Crane
- Oak Spring Garden Foundation, 1776 Loughborough Lane, Upperville, Virginia 20184, USA
- Yale School of Forestry and Environmental Studies, 195 Prospect Street, New Haven, Connecticut 06511, USA
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Breuil-Broyer S, Trehin C, Morel P, Boltz V, Sun B, Chambrier P, Ito T, Negrutiu I. Analysis of the Arabidopsis superman allelic series and the interactions with other genes demonstrate developmental robustness and joint specification of male-female boundary, flower meristem termination and carpel compartmentalization. ANNALS OF BOTANY 2016; 117:905-23. [PMID: 27098089 PMCID: PMC4845806 DOI: 10.1093/aob/mcw023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/14/2015] [Accepted: 01/26/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS SUPERMAN is a cadastral gene controlling the sexual boundary in the flower. The gene's functions and role in flower development and evolution have remained elusive. The analysis of a contrasting SUP allelic series (for which the names superman, superwoman and supersex have been coined) makes it possible to distinguish early vs. late regulatory processes at the flower meristem centre to which SUP is an important contributor. Their understanding is essential in further addressing evolutionary questions linking bisexuality and flower meristem homeostasis. METHODS Inter-allelic comparisons were carried out and SUP interactions with other boundary factors and flower meristem patterning and homeostasis regulators (such as CLV, WUS, PAN, CUC, KNU, AG, AP3/PI, CRC and SPT) have been evaluated at genetic, molecular, morphological and histological levels. KEY RESULTS Early SUP functions include mechanisms of male-female (sexual) boundary specification, flower mersitem termination and control of stamen number. A SUP-dependent flower meristem termination pathway is identified and analysed. Late SUP functions play a role in organ morphogenesis by controlling intra-whorl organ separation and carpel medial region formation. By integrating early and late SUP functions, and by analyzing in one single experiment a series of SUP genetic interactions, the concept of meristematic 'transference' (cascade) - a regulatory bridging process redundantly and sequentially co-ordinating the triggering and completion of flower meristem termination, and carpel margin meristem and placenta patterning - is proposed. CONCLUSIONS Taken together, the results strongly support the view that SUP(-type) function(s) have been instrumental in resolving male/female gradients into sharp male and female identities (whorls, organs) and in enforcing flower homeostasis during evolution. This has probably been achieved by incorporating the meristem patterning system of the floral axis into the female/carpel programme.
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Key Words
- Arabidopsis
- SUPERMAN gene: superman, clark-kent/superwoman, supersex, AG, CLV, CRC, CUC2, KNU, PAN, SPT, WUS
- allelic series
- carpel
- evo-devo
- flower homeostasis
- flower meristem determinacy
- flower pattern
- meristematic ‘cascade’/transference
- pistillody/carpelloidy
- placenta
- stamen
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Affiliation(s)
| | - Christophe Trehin
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Patrice Morel
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Véronique Boltz
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Bo Sun
- School of Life Sciences, Nanjing University, Nanjing City, Jiangsu Province, China 210093 Temasek Life Sciences Laboratory 1 Research Link National University of Singapore Singapore 117604
| | - Pierre Chambrier
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Toshiro Ito
- Temasek Life Sciences Laboratory 1 Research Link National University of Singapore Singapore 117604 Nara Institute of Science and Technology 8916-5 Takayama, Ikoma, Japan
| | - Ioan Negrutiu
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
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Rudall PJ, Alves M, Sajo MDG. Inside-out flowers of Lacandonia brasiliana (Triuridaceae) provide new insights into fundamental aspects of floral patterning. PeerJ 2016; 4:e1653. [PMID: 26870611 PMCID: PMC4748704 DOI: 10.7717/peerj.1653] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/12/2016] [Indexed: 11/30/2022] Open
Abstract
Background and Aims. A recently described Brazilian species, Lacandonia brasiliana, shares with its longer established putative sister species from Mexico, L. schismatica, inverted floral patterning (carpels surrounding stamens) that is almost unique among angiosperms. We present a detailed ontogenetic study of L. brasiliana for comparison with other members of the tribe Triurideae (Triuridaceae) to explore the possible evolutionary origins of “inside-out” flowers. Methods. Wild-source populations of L. brasiliana were compared morphologically and ontogenetically with related species of Triurideae, using light and scanning electron microscopy. Key Results. Relatively few morphological differences separate flowers of L. brasiliana and L. schismatica. Both species have tepals with late-developing subapical appendages. In both species, the three central (almost sessile) anthers develop precociously with respect to the carpels; the anthers remain closed, and fertilization is achieved via pollen-tube growth from germinating pollen grains of the same cleistogamous flower. Carpels are initiated on fascicles. Conclusions. The close similarity between the two Lacandonia species makes it unlikely that they arose independently from two separate homeotic transformation events; they could either represent sister species or two populations of a single disjunct species. Our study underlines the problematic generic and species boundaries within Triurideae. We present an evolutionary scenario of character evolution in Triuridaceae. The inside-out Lacandonia flower could have resulted from a stabilized homeotic transformation; this hypothesis is not in conflict with constrasting theories of the origin of the Triuridaceae flower, which coincided with a shift to unisexuality. The unisexual yet highly plastic flowers that are typical of Triuridaceae could have pre-adapted the origin of the extraordinary Lacandonia morphology.
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Affiliation(s)
- Paula J Rudall
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew , United Kingdom
| | - Marccus Alves
- Dept. Botânica, Universidade Federal de Pernambuco , Recife, Pernambuco , Brazil
| | - Maria das Graças Sajo
- Instituto de Biociências, Universidade Estadual Paulista , Rio Claro, São Paulo , Brazil
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Xi Z, Rest JS, Davis CC. Phylogenomics and coalescent analyses resolve extant seed plant relationships. PLoS One 2013; 8:e80870. [PMID: 24278335 PMCID: PMC3836751 DOI: 10.1371/journal.pone.0080870] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 10/15/2013] [Indexed: 12/29/2022] Open
Abstract
The extant seed plants include more than 260,000 species that belong to five main lineages: angiosperms, conifers, cycads, Ginkgo, and gnetophytes. Despite tremendous effort using molecular data, phylogenetic relationships among these five lineages remain uncertain. Here, we provide the first broad coalescent-based species tree estimation of seed plants using genome-scale nuclear and plastid data By incorporating 305 nuclear genes and 47 plastid genes from 14 species, we identify that i) extant gymnosperms (i.e., conifers, cycads, Ginkgo, and gnetophytes) are monophyletic, ii) gnetophytes exhibit discordant placements within conifers between their nuclear and plastid genomes, and iii) cycads plus Ginkgo form a clade that is sister to all remaining extant gymnosperms. We additionally observe that the placement of Ginkgo inferred from coalescent analyses is congruent across different nucleotide rate partitions. In contrast, the standard concatenation method produces strongly supported, but incongruent placements of Ginkgo between slow- and fast-evolving sites. Specifically, fast-evolving sites yield relationships in conflict with coalescent analyses. We hypothesize that this incongruence may be related to the way in which concatenation methods treat sites with elevated nucleotide substitution rates. More empirical and simulation investigations are needed to understand this potential weakness of concatenation methods.
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Affiliation(s)
- Zhenxiang Xi
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Joshua S. Rest
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, United States of America
| | - Charles C. Davis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail:
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Ruelens P, de Maagd RA, Proost S, Theißen G, Geuten K, Kaufmann K. FLOWERING LOCUS C in monocots and the tandem origin of angiosperm-specific MADS-box genes. Nat Commun 2013; 4:2280. [DOI: 10.1038/ncomms3280] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 07/10/2013] [Indexed: 12/11/2022] Open
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Pellicer J, Kelly L, Magdalena C, Leitch I. Insights into the dynamics of genome size and chromosome evolution in the early diverging angiosperm lineage Nymphaeales (water lilies). Genome 2013; 56:437-49. [DOI: 10.1139/gen-2013-0039] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Nymphaeales are the most species-rich lineage of the earliest diverging angiosperms known as the ANA grade (Amborellales, Nymphaeales, Austrobaileyales), and they have received considerable attention from morphological, physiological, and ecological perspectives. Although phylogenetic relationships between these three lineages of angiosperms are mainly well resolved, insights at the whole genome level are still limited because of a dearth of information. To address this, genome sizes and chromosome numbers in 34 taxa, comprising 28 species were estimated and analysed together with previously published data to provide an overview of genome size and chromosome diversity in Nymphaeales. Overall, genome sizes were shown to vary 10-fold and chromosome numbers and ploidy levels ranged from 2n = 2x = 18 to 2n = 16x = ∼224. Distinct patterns of genome diversity were apparent, reflecting the differential incidence of polyploidy, changes in repetitive DNA content, and chromosome rearrangements within and between genera. Using model-based approaches, ancestral genome size and basic chromosome numbers were reconstructed to provide insights into the dynamics of genome size and chromosome number evolution. Finally, by combining additional data from Amborellales and Austrobaileyales, a comprehensive overview of genome sizes and chromosome numbers in these early diverging angiosperms is presented.
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Affiliation(s)
- J. Pellicer
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - L.J. Kelly
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
- Queen Mary University of London, School of Biological and Chemical Science, London E1 4NS, UK
| | - C. Magdalena
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - I.J. Leitch
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
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Wu CS, Chaw SM, Huang YY. Chloroplast phylogenomics indicates that Ginkgo biloba is sister to cycads. Genome Biol Evol 2013; 5:243-54. [PMID: 23315384 PMCID: PMC3595029 DOI: 10.1093/gbe/evt001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2013] [Indexed: 12/23/2022] Open
Abstract
Molecular phylogenetic studies have not yet reached a consensus on the placement of Ginkgoales, which is represented by the only living species, Ginkgo biloba (common name: ginkgo). At least six discrepant placements of ginkgo have been proposed. This study aimed to use the chloroplast phylogenomic approach to examine possible factors that lead to such disagreeing placements. We found the sequence types used in the analyses as the most critical factor in the conflicting placements of ginkgo. In addition, the placement of ginkgo varied in the trees inferred from nucleotide (NU) sequences, which notably depended on breadth of taxon sampling, tree-building methods, codon positions, positions of Gnetopsida (common name: gnetophytes), and including or excluding gnetophytes in data sets. In contrast, the trees inferred from amino acid (AA) sequences congruently supported the monophyly of a ginkgo and Cycadales (common name: cycads) clade, regardless of which factors were examined. Our site-stripping analysis further revealed that the high substitution saturation of NU sequences mainly derived from the third codon positions and contributed to the variable placements of ginkgo. In summary, the factors we surveyed did not affect results inferred from analyses of AA sequences. Congruent topologies in our AA trees give more confidence in supporting the ginkgo-cycad sister-group hypothesis.
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Affiliation(s)
- Chung-Shien Wu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Shu-Miaw Chaw
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Ya-Yi Huang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
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Williams JH. Pollen Tube Growth Rates and the Diversification of Flowering Plant Reproductive Cycles. INTERNATIONAL JOURNAL OF PLANT SCIENCES 2012. [PMID: 0 DOI: 10.1086/665822] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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16
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Iles WJD, Rudall PJ, Sokoloff DD, Remizowa MV, Macfarlane TD, Logacheva MD, Graham SW. Molecular phylogenetics of Hydatellaceae (Nymphaeales): sexual-system homoplasy and a new sectional classification. AMERICAN JOURNAL OF BOTANY 2012; 99:663-676. [PMID: 22473977 DOI: 10.3732/ajb.1100524] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Species relationships are unknown in Hydatellaceae, a small family of dwarf aquatics related to water lilies that arose near the base of angiosperm phylogeny. Here we use molecular evidence to infer a species tree for the family and apply this to reconstructing major transitions in morphology and sexual system in this early branch of angiosperms. METHODS We assembled plastid (atpB, matK, ndhF, rbcL) and nuclear (ribosomal ITS) data for 50 samples (including outgroups) and estimated a species tree for Hydatellaceae using a Bayesian multispecies coalescent approach. We reconstructed the evolution of several morphological characters, then tested for associations between sexual system and reproductive morphology using phylogenetic ANOVA. KEY RESULTS Dioecious species of Hydatellaceae have significantly greater stamen number and anther length than do cosexual species, suggesting changes in male function. The perennial habit that defines one subclade likely represents a reversion from annuality. Species relationships do not fall along traditional morphological divisions, but new sections proposed here are supported by fruit and seed synapomorphies. The earliest split in the family is reflected in geography and climate (i.e., tropical vs. subtropical/temperate clades). We found limited evidence of incongruence between plastid and nuclear trees, with one exception involving gene-tree nonmonophyly for two close relatives (Trithuria submersa, T. bibracteata). CONCLUSIONS While the direction of sexual-system evolution is ambiguous, transitions are significantly associated with changes in involucral phyllome length and proxies of pollen production. We propose a new sectional circumscription based on fruit, seed, and DNA evidence.
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Affiliation(s)
- William J D Iles
- UBC Botanical Garden & Centre for Plant Research, and Department of Botany, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada.
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Taylor ML, Williams JH. Pollen tube development in two species of Trithuria (Hydatellaceae) with contrasting breeding systems. ACTA ACUST UNITED AC 2012; 25:83-96. [DOI: 10.1007/s00497-012-0183-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/08/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Mackenzie L Taylor
- Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
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18
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Vialette-Guiraud ACM, Alaux M, Legeai F, Finet C, Chambrier P, Brown SC, Chauvet A, Magdalena C, Rudall PJ, Scutt CP. Cabomba as a model for studies of early angiosperm evolution. ANNALS OF BOTANY 2011; 108:589-98. [PMID: 21486926 PMCID: PMC3170152 DOI: 10.1093/aob/mcr088] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Accepted: 03/02/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND The angiosperms, or flowering plants, diversified in the Cretaceous to dominate almost all terrestrial environments. Molecular phylogenetic studies indicate that the orders Amborellales, Nymphaeales and Austrobaileyales, collectively termed the ANA grade, diverged as separate lineages from a remaining angiosperm clade at a very early stage in flowering plant evolution. By comparing these early diverging lineages, it is possible to infer the possible morphology and ecology of the last common ancestor of the extant angiosperms, and this analysis can now be extended to try to deduce the developmental mechanisms that were present in early flowering plants. However, not all species in the ANA grade form convenient molecular-genetic models. SCOPE The present study reviews the genus Cabomba (Nymphaeales), which shows a range of features that make it potentially useful as a genetic model. We focus on characters that have probably been conserved since the last common ancestor of the extant flowering plants. To facilitate the use of Cabomba as a molecular model, we describe methods for its cultivation to flowering in the laboratory, a novel Cabomba flower expressed sequence tag database, a well-adapted in situ hybridization protocol and a measurement of the nuclear genome size of C. caroliniana. We discuss the features required for species to become tractable models, and discuss the relative merits of Cabomba and other ANA-grade angiosperms in molecular-genetic studies aimed at understanding the origin of the flowering plants.
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Affiliation(s)
- Aurelie C. M. Vialette-Guiraud
- Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - Michael Alaux
- INRA-URGI Centre de Versailles, Bâtiment 18, Route de Saint-Cyr, 78026 Versailles Cedex, France
| | - Fabrice Legeai
- UMR Bio3P, Campus de Beaulieu, 35042 Rennes Cedex, France
| | - Cedric Finet
- Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - Pierre Chambrier
- Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - Spencer C. Brown
- Institut des Sciences du Végétal CNRS UPR2355, Bâtiment 23, Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
| | - Aurelie Chauvet
- Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | | | | | - Charles P. Scutt
- Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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Prenner G, Cacho NI, Baum D, Rudall PJ. Is LEAFY a useful marker gene for the flower-inflorescence boundary in the Euphorbia cyathium? JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:345-50. [PMID: 20965944 PMCID: PMC2993917 DOI: 10.1093/jxb/erq275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The flower-like reproductive structure of Euphorbia s.l. (Euphorbiaceae) is widely believed to have evolved from an inflorescence, and is therefore interpreted as a special type of pseudanthium, termed a cyathium. However, fuzzy morphological boundaries between the inflorescence, individual flowers, and organs have fuelled the suggestion that the cyathium does not merely superficially resemble a flower but could actually share developmental genetic pathways with a conventional flower. To test this hypothesis, immunolocalizations of FLORICAULA/LEAFY (LFY), a protein associated with floral identity in many angiosperm species, were performed in developing cyathia of different species of Euphorbia. Expression of the LFY protein was found not only in individual floral primordia (as predicted from results in the model organisms Arabidopsis and Anthirrhinum), but also in the cyathium primordium and in the primordia of partial male inflorescences. These results provide further evidence that the evolution of floral traits in pseudanthial inflorescences often involves expression of floral development genes in the inflorescence apex. This finding blurs the conventional rigid distinction between flowers and inflorescences.
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Affiliation(s)
- Gerhard Prenner
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK.
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Conservation and canalization of gene expression during angiosperm diversification accompany the origin and evolution of the flower. Proc Natl Acad Sci U S A 2010; 107:22570-5. [PMID: 21149731 DOI: 10.1073/pnas.1013395108] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origin and rapid diversification of the angiosperms (Darwin's "Abominable Mystery") has engaged generations of researchers. Here, we examine the floral genetic programs of phylogenetically pivotal angiosperms (water lily, avocado, California poppy, and Arabidopsis) and a nonflowering seed plant (a cycad) to obtain insight into the origin and subsequent evolution of the flower. Transcriptional cascades with broadly overlapping spatial domains, resembling the hypothesized ancestral gymnosperm program, are deployed across morphologically intergrading organs in water lily and avocado flowers. In contrast, spatially discrete transcriptional programs in distinct floral organs characterize the more recently derived angiosperm lineages represented by California poppy and Arabidopsis. Deep evolutionary conservation in the genetic programs of putatively homologous floral organs traces to those operating in gymnosperm reproductive cones. Female gymnosperm cones and angiosperm carpels share conserved genetic features, which may be associated with the ovule developmental program common to both organs. However, male gymnosperm cones share genetic features with both perianth (sterile attractive and protective) organs and stamens, supporting the evolutionary origin of the floral perianth from the male genetic program of seed plants.
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21
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Crane PR, Friis EM, Chaloner WG. Darwin and the evolution of flowers. Philos Trans R Soc Lond B Biol Sci 2010; 365:347-50. [DOI: 10.1098/rstb.2009.0277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Peter R. Crane
- School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT 06511, USA
| | - Else Marie Friis
- Department of Palaeobotany, Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden
| | - William G. Chaloner
- Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK
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