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Scutt CP. Model Species to Investigate the Origin of Flowers. Methods Mol Biol 2023; 2686:83-109. [PMID: 37540355 DOI: 10.1007/978-1-0716-3299-4_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
The angiosperms, or flowering plants, arose at least 135 million years ago (Ma) and rapidly diversified to form over 300,000 species alive today. This group appears, however, to have separated from its closest living relatives, the extant gymnosperms, much earlier: over 300 Ma. Representatives of basally-diverging angiosperm lineages are of key importance to studies aimed at reconstructing the most recent common ancestor of living angiosperms, including its morphological, anatomical, eco-physiological and molecular aspects. Furthermore, evo-devo comparisons of angiosperms with living gymnosperms may help to determine how the many novel aspects of angiosperms, including those of the flower, first came about. This chapter reviews literature on the origin of angiosperms and focusses on basally-diverging angiosperms and gymnosperms that show advantages as potential experimental models, reviewing information and protocols for the use of these species in an evo-devo context. The final section suggests a means by which data from living and fossil groups could be integrated to better elucidate evolutionary events that took place on the long stem-lineage that apparently preceded the radiation of living angiosperms.
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Affiliation(s)
- Charles P Scutt
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon-1, CNRS, INRA, Lyon, France.
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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Trithuria brevistyla (Hydatellaceae), a new combination for the New Zealand endemic species from the South Island. UKRAINIAN BOTANICAL JOURNAL 2019. [DOI: 10.15407/ukrbotj76.02.095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Anger N, Fogliani B, Scutt CP, Gâteblé G. Dioecy in Amborella trichopoda: evidence for genetically based sex determination and its consequences for inferences of the breeding system in early angiosperms. ANNALS OF BOTANY 2017; 119:591-597. [PMID: 28110266 PMCID: PMC5604545 DOI: 10.1093/aob/mcw278] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/09/2016] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS This work aimed to gain insight into the breeding system at the base of living angiosperms through both character state reconstructions and the study of sex ratios and phenotypes in the likely sister to all other living angiosperms, Amborella trichopoda . METHODS Sex phenotypes were mapped onto a phylogeny of basally diverging angiosperms using maximum parsimony. In parallel, sex ratios and phenotypes were studied over two consecutive flowering seasons in an ex situ population of A. trichopoda , while the sex ratio of an in situ population was also assessed. KEY RESULTS Parsimony analyses failed to resolve the breeding system present at the base of living angiosperms, but indicated the importance of A. trichopoda for the future elucidation of this question. The ex situ A. trichopoda population studied showed a primary sex ratio close to 1:1, though sex ratio bias was found in the in situ population studied. Instances of sexual instability were quantified in both populations. CONCLUSIONS Sex ratio data support the presence of genetic sex determination in A. trichopoda , whose further elucidation may guide inferences on the breeding system at the base of living angiosperms. Sexual instability in A. trichopoda suggests the operation of epigenetic mechanisms, and the evolution of dioecy via a gynodioecious intermediate.
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Affiliation(s)
- Nicolas Anger
- Institut Agronomique néo-Calédonien (IAC), BP 73 Port Laguerre, 98890 Païta, New Caledonia
| | - Bruno Fogliani
- Institut Agronomique néo-Calédonien (IAC), BP 73 Port Laguerre, 98890 Païta, New Caledonia
- Université de la Nouvelle-Calédonie (UNC), Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), 98851 Nouméa, New Caledonia
| | - Charles P. Scutt
- Laboratoire de Reproduction et Développement des Plantes (UMR 5667: CNRS-INRA-Université de Lyon), Ecole Normale Supérieure de Lyon (ENS-Lyon), 46 allée d’Italie, 69364 Lyon Cedex 07, France
| | - Gildas Gâteblé
- Institut Agronomique néo-Calédonien (IAC), BP 73 Port Laguerre, 98890 Païta, New Caledonia
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Chen F, Liu X, Yu C, Chen Y, Tang H, Zhang L. Water lilies as emerging models for Darwin's abominable mystery. HORTICULTURE RESEARCH 2017; 4:17051. [PMID: 28979789 PMCID: PMC5626932 DOI: 10.1038/hortres.2017.51] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 06/30/2017] [Accepted: 07/26/2017] [Indexed: 05/02/2023]
Abstract
Water lilies are not only highly favored aquatic ornamental plants with cultural and economic importance but they also occupy a critical evolutionary space that is crucial for understanding the origin and early evolutionary trajectory of flowering plants. The birth and rapid radiation of flowering plants has interested many scientists and was considered 'an abominable mystery' by Charles Darwin. In searching for the angiosperm evolutionary origin and its underlying mechanisms, the genome of Amborella has shed some light on the molecular features of one of the basal angiosperm lineages; however, little is known regarding the genetics and genomics of another basal angiosperm lineage, namely, the water lily. In this study, we reviewed current molecular research and note that water lily research has entered the genomic era. We propose that the genome of the water lily is critical for studying the contentious relationship of basal angiosperms and Darwin's 'abominable mystery'. Four pantropical water lilies, especially the recently sequenced Nymphaea colorata, have characteristics such as small size, rapid growth rate and numerous seeds and can act as the best model for understanding the origin of angiosperms. The water lily genome is also valuable for revealing the genetics of ornamental traits and will largely accelerate the molecular breeding of water lilies.
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Affiliation(s)
- Fei Chen
- Center for Genomics and Biotechnology; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology; Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xing Liu
- Center for Genomics and Biotechnology; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology; Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Cuiwei Yu
- Zhejiang Humanities Landscape Co., LTD, Hangzhou 310030, China
| | - Yuchu Chen
- Zhejiang Humanities Landscape Co., LTD, Hangzhou 310030, China
| | - Haibao Tang
- Center for Genomics and Biotechnology; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology; Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liangsheng Zhang
- Center for Genomics and Biotechnology; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology; Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Marques I, Montgomery SA, Barker MS, Macfarlane TD, Conran JG, Catalán P, Rieseberg LH, Rudall PJ, Graham SW. Transcriptome-derived evidence supports recent polyploidization and a major phylogeographic division in Trithuria submersa (Hydatellaceae, Nymphaeales). THE NEW PHYTOLOGIST 2016; 210:310-323. [PMID: 26612464 DOI: 10.1111/nph.13755] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
Relatively little is known about species-level genetic diversity in flowering plants outside the eudicots and monocots, and it is often unclear how to interpret genetic patterns in lineages with whole-genome duplications. We addressed these issues in a polyploid representative of Hydatellaceae, part of the water-lily order Nymphaeales. We examined a transcriptome of Trithuria submersa for evidence of recent whole-genome duplication, and applied transcriptome-derived microsatellite (expressed-sequence tag simple-sequence repeat (EST-SSR)) primers to survey genetic variation in populations across its range in mainland Australia. A transcriptome-based Ks plot revealed at least one recent polyploidization event, consistent with fixed heterozygous genotypes representing underlying sets of homeologous loci. A strong genetic division coincides with a trans-Nullarbor biogeographic boundary. Patterns of 'allelic' variation (no more than two variants per EST-SSR genotype) and recently published chromosomal evidence are consistent with the predicted polyploidization event and substantial homozygosity underlying fixed heterozygote SSR genotypes, which in turn reflect a selfing mating system. The Nullarbor Plain is a barrier to gene flow between two deep lineages of T. submersa that may represent cryptic species. The markers developed here should also be useful for further disentangling species relationships, and provide a first step towards future genomic studies in Trithuria.
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Affiliation(s)
- Isabel Marques
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
- UBC Botanical Garden & Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, BC, V6T 1Z4, Canada
- Department of Agricultural and Environmental Sciences, High Polytechnic School of Huesca, University of Zaragoza, C/Carretera de Cuarte Km 1, Huesca, E22071, Spain
| | - Sean A Montgomery
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
- UBC Botanical Garden & Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, BC, V6T 1Z4, Canada
| | - Michael S Barker
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Terry D Macfarlane
- Western Australian Herbarium, Science and Conservation Division, Department of Parks and Wildlife, Locked Bag 104, Bentley Delivery Centre, Bentley, WA, 6983, Australia
| | - John G Conran
- School of Biological Sciences, Australian Centre for Evolutionary Biology and Biodiversity & Sprigg Geobiology Centre, The University of Adelaide, Benham Bldg DX 650 312, Adelaide, SA, 5005, Australia
| | - Pilar Catalán
- Department of Agricultural and Environmental Sciences, High Polytechnic School of Huesca, University of Zaragoza, C/Carretera de Cuarte Km 1, Huesca, E22071, Spain
- Department of Botany, Institute of Biology, Tomsk State University, Lenin Av. 36, Tomsk, 634050, Russia
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
| | - Paula J Rudall
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK
| | - Sean W Graham
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
- UBC Botanical Garden & Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, BC, V6T 1Z4, Canada
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Correlations of life form, pollination mode and sexual system in aquatic angiosperms. PLoS One 2014; 9:e115653. [PMID: 25525810 PMCID: PMC4272260 DOI: 10.1371/journal.pone.0115653] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 11/26/2014] [Indexed: 11/19/2022] Open
Abstract
Aquatic plants are phylogenetically well dispersed across the angiosperms. Reproductive and other life-history traits of aquatic angiosperms are closely associated with specific growth forms. Hydrophilous pollination exhibits notable examples of convergent evolution in angiosperm reproductive structures, and hydrophiles exhibit great diversity in sexual system. In this study, we reconstructed ancestral characters of aquatic lineages based on the phylogeny of aquatic angiosperms. Our aim is to find the correlations of life form, pollination mode and sexual system in aquatic angiosperms. Hydrophily is the adaptive evolution of completely submersed angiosperms to aquatic habitats. Hydroautogamy and maleflower-ephydrophily are the transitional stages from anemophily and entomophily to hydrophily. True hydrophily occurs in 18 submersed angiosperm genera, which is associated with an unusually high incidence of unisexual flowers. All marine angiosperms are submersed, hydrophilous species. This study would help us understand the evolution of hydrophilous pollination and its correlations with life form and sexual system.
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Rix MG, Edwards DL, Byrne M, Harvey MS, Joseph L, Roberts JD. Biogeography and speciation of terrestrial fauna in the south-western Australian biodiversity hotspot. Biol Rev Camb Philos Soc 2014; 90:762-93. [PMID: 25125282 DOI: 10.1111/brv.12132] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 06/28/2014] [Accepted: 07/02/2014] [Indexed: 01/21/2023]
Abstract
The south-western land division of Western Australia (SWWA), bordering the temperate Southern and Indian Oceans, is the only global biodiversity hotspot recognised in Australia. Renowned for its extraordinary diversity of endemic plants, and for some of the largest and most botanically significant temperate heathlands and woodlands on Earth, SWWA has long fascinated biogeographers. Its flat, highly weathered topography and the apparent absence of major geographic factors usually implicated in biotic diversification have challenged attempts to explain patterns of biogeography and mechanisms of speciation in the region. Botanical studies have always been central to understanding the biodiversity values of SWWA, although surprisingly few quantitative botanical analyses have allowed for an understanding of historical biogeographic processes in both space and time. Faunistic studies, by contrast, have played little or no role in defining hotspot concepts, despite several decades of accumulating quantitative research on the phylogeny and phylogeography of multiple lineages. In this review we critically analyse datasets with explicit supporting phylogenetic data and estimates of the time since divergence for all available elements of the terrestrial fauna, and compare these datasets to those available for plants. In situ speciation has played more of a role in shaping the south-western Australian fauna than has long been supposed, and has occurred in numerous endemic lineages of freshwater fish, frogs, reptiles, snails and less-vagile arthropods. By contrast, relatively low levels of endemism are found in birds, mammals and highly dispersive insects, and in situ speciation has played a negligible role in generating local endemism in birds and mammals. Quantitative studies provide evidence for at least four mechanisms driving patterns of endemism in south-western Australian animals, including: (i) relictualism of ancient Gondwanan or Pangaean taxa in the High Rainfall Province; (ii) vicariant isolation of lineages west of the Nullarbor divide; (iii) in situ speciation; and (iv) recent population subdivision. From dated quantitative studies we derive four testable models of historical biogeography for animal taxa in SWWA, each explicit in providing a spatial, temporal and topological perspective on patterns of speciation or divergence. For each model we also propose candidate lineages that may be worthy of further study, given what we know of their taxonomy, distributions or relationships. These models formalise four of the strongest patterns seen in many animal taxa from SWWA, although other models are clearly required to explain particular, idiosyncratic patterns. Generating numerous new datasets for suites of co-occurring lineages in SWWA will help refine our understanding of the historical biogeography of the region, highlight gaps in our knowledge, and allow us to derive general postulates from quantitative (rather than qualitative) results. For animals, this process has now begun in earnest, as has the process of taxonomically documenting many of the more diverse invertebrate lineages. The latter remains central to any attempt to appreciate holistically biogeographic patterns and processes in SWWA, and molecular phylogenetic studies should - where possible - also lead to tangible taxonomic outcomes.
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Affiliation(s)
- Michael G Rix
- Australian Centre for Evolutionary Biology and Biodiversity, School of Earth and Environmental Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia
| | - Danielle L Edwards
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06520, U.S.A
| | - Margaret Byrne
- Science Division, Department of Parks and Wildlife, Locked Bag 104, Bentley DC, Western Australia 6983, Australia
| | - Mark S Harvey
- Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia.,School of Animal Biology, Centre for Evolutionary Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Leo Joseph
- Australian National Wildlife Collection, CSIRO National Facilities and Collections, GPO Box 1700, Canberra, Australian Capital Territory 2601, Australia
| | - J Dale Roberts
- Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia.,School of Animal Biology, Centre for Evolutionary Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.,Centre of Excellence in Natural Resource Management, University of Western Australia, PO Box 5771, Albany, Western Australia 6332, Australia
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Reconstructing the age and historical biogeography of the ancient flowering-plant family Hydatellaceae (Nymphaeales). BMC Evol Biol 2014; 14:102. [PMID: 24884487 PMCID: PMC4030046 DOI: 10.1186/1471-2148-14-102] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/01/2014] [Indexed: 12/26/2022] Open
Abstract
Background The aquatic flowering-plant family Hydatellaceae has a classic Gondwanan distribution, as it is found in Australia, India and New Zealand. To shed light on the biogeographic history of this apparently ancient branch of angiosperm phylogeny, we dated the family in the context of other seed-plant divergences, and evaluated its biogeography using parsimony and likelihood methods. We also explicitly tested the effect of different extinction rates on biogeographic inferences. Results We infer that the stem lineage of Hydatellaceae originated in the Lower Cretaceous; in contrast, its crown originated much more recently, in the early Miocene, with the bulk of its diversification after the onset of the Pliocene. Biogeographic reconstructions predict a mix of dispersal and vicariance events, but considerations of geological history preclude most vicariance events, besides a split at the root of the family between southern and northern clades. High extinction rates are plausible in the family, and when these are taken into account there is greater uncertainty in biogeographic inferences. Conclusions A stem origin for Hydatellaceae in the Lower Cretaceous is consistent with the initial appearance of fossils attributed to its sister clade, the water lilies. In contrast, the crown clade is young, indicating that vicariant explanations for species outside Australia are improbable. Although long-distance dispersal is likely the primary driver of biogeographic distribution in Hydatellaceae, we infer that the recent drying out of central Australia divided the family into tropical vs. subtropical/temperate clades around the beginning of the Miocene.
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Costa M, Pereira AM, Rudall PJ, Coimbra S. Immunolocalization of arabinogalactan proteins (AGPs) in reproductive structures of an early-divergent angiosperm, Trithuria (Hydatellaceae). ANNALS OF BOTANY 2013; 111. [PMID: 23186834 PMCID: PMC3555524 DOI: 10.1093/aob/mcs256] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS Trithuria is the sole genus of Hydatellaceae, a family of the early-divergent angiosperm lineage Nymphaeales (water-lilies). In this study different arabinogalactan protein (AGP) epitopes in T. submersa were evaluated in order to understand the diversity of these proteins and their functions in flowering plants. METHODS Immunolabelling of different AGPs and pectin epitopes in reproductive structures of T. submersa at the stage of early seed development was achieved by immunofluorescence of specific antibodies. KEY RESULTS AGPs in Trithuria pistil tissues could be important as structural proteins and also as possible signalling molecules. Intense labelling was obtained with anti-AGP antibodies both in the anthers and in the intine wall, the latter associated with pollen tube emergence. CONCLUSIONS AGPs could play a significant role in Trithuria reproduction, due to their specific presence in the pollen tube pathway. The results agree with labellings obtained for Arabidopsis and confirms the importance of AGPs in angiosperm reproductive structures as essential structural components and probably important signalling molecules.
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Affiliation(s)
- Mário Costa
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
| | - Ana Marta Pereira
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AAB, UK
| | - Sílvia Coimbra
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre 4169-007 Porto, Portugal
- BioFIG, Center for Biodiversity, Functional and Integrative Genomics, Portugal
- For correspondence. E-mail
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Friedman WE, Bachelier JB, Hormaza JI. Embryology in Trithuria submersa (Hydatellaceae) and relationships between embryo, endosperm, and perisperm in early-diverging flowering plants. AMERICAN JOURNAL OF BOTANY 2012; 99:1083-95. [PMID: 22688427 DOI: 10.3732/ajb.1200066] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
PREMISE OF THE STUDY Despite their highly reduced morphology, Hydatellaceae bear the unmistakable embryological signature of Nymphaeales, including a starch-rich maternal perisperm and a minute biparental endosperm and embryo. The co-occurrence of perisperm and endosperm in Nymphaeales and other lineages of flowering plants, and their respective functions during the course of seed development and embryo germination, remain enigmatic. METHODS Development of the embryo, endosperm, and perisperm was examined histologically from fertilization through germination in flowers and fruits of Trithuria submersa. KEY RESULTS The embryo of T. submersa initiates two cotyledons prior to seed maturity/dormancy, and their tips remain in contact with the endosperm throughout germination. The endosperm persists as a single layer of cells and serves as the interface between the embryo and the perisperm. The perisperm contains carbohydrates and proteins, and functions as the main storage tissue. The endosperm accumulates proteins and aleurone grains and functions as a transfer cell layer. CONCLUSIONS In Nymphaeales, the multiple roles of a more typical endosperm have been separated into two different tissues and genetic entities: a maternal perisperm (nutrient acquisition, storage, mobilization) and a minute biparental endosperm (nutrient transfer to the embryo). The presence of perisperms among several other ancient lineages of angiosperms suggests a modest degree of developmental and functional lability for the nutrient storage tissue (perisperm or endosperm) within seeds during the early evolution of flowering plants. Finally, we examine the evolutionary developmental hypothesis that, contrary to longstanding assumptions, an embryo-nourishing perisperm along with a minute endosperm may represent the plesiomorphic condition for flowering plants.
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Affiliation(s)
- William E Friedman
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138 USA.
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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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