1
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Hetherington AJ. The role of fossils for reconstructing the evolution of plant development. Development 2024; 151:dev204322. [PMID: 39417682 DOI: 10.1242/dev.204322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Many of the developmental innovations that underpin the diversity of plant form alive today, such as those facilitating apical growth, branching, leaves, roots, wood and seeds, all evolved over 360 million years ago. Fossils, as our only direct record of plant form in the past, are thus essential for interpreting the origin and evolution of these innovations. The focus of this Spotlight is to showcase the rich plant fossil record open for developmental interpretation and to cement the role that fossils play at a time when increases in genome sequencing and new model species make tackling major questions in the area of plant evolution and development tractable for the first time.
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Affiliation(s)
- Alexander J Hetherington
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
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2
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Li M, Wu S. Root evolution: Evidence for convergent evolution of root meristem. Curr Biol 2023; 33:R1009-R1010. [PMID: 37816319 DOI: 10.1016/j.cub.2023.08.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
The root system is thought to have evolved independently during the process of plant terrestrialization. It is unclear how the molecular regulation of the root meristem has been modified during these independent root evolutions. Two new reports provide important evidence in support of the putative convergent evolution of lycophyte roots.
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Affiliation(s)
- Meng Li
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shuang Wu
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China.
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3
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Mitchell RL, Kenrick P, Pressel S, Duckett J, Strullu-Derrien C, Davies N, McMahon WJ, Summerfield R. Terrestrial surface stabilisation by modern analogues of the earliest land plants: A multi-dimensional imaging study. GEOBIOLOGY 2023; 21:454-473. [PMID: 36779552 DOI: 10.1111/gbi.12546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/23/2022] [Accepted: 01/05/2023] [Indexed: 06/13/2023]
Abstract
The evolution of the first plant-based terrestrial ecosystems in the early Palaeozoic had a profound effect on the development of soils, the architecture of sedimentary systems, and shifts in global biogeochemical cycles. In part, this was due to the evolution of complex below-ground (root-like) anchorage systems in plants, which expanded and promoted plant-mineral interactions, weathering, and resulting surface sediment stabilisation. However, little is understood about how these micro-scale processes occurred, because of a lack of in situ plant fossils in sedimentary rocks/palaeosols that exhibit these interactions. Some modern plants (e.g., liverworts, mosses, lycophytes) share key features with the earliest land plants; these include uni- or multicellular rhizoid-like anchorage systems or simple roots, and the ability to develop below-ground networks through prostrate axes, and intimate associations with fungi, making them suitable analogues. Here, we investigated cryptogamic ground covers in Iceland and New Zealand to better understand these interactions, and how they initiate the sediment stabilisation process. We employed multi-dimensional and multi-scale imaging, including scanning electron microscopy (SEM) and X-ray Computed Tomography (μCT) of non-vascular liverworts (Haplomitriopsida and complex thalloids) and mosses, with additional imaging of vascular lycopods. We find that plants interact with their substrate in multiple ways, including: (1) through the development of extensive surface coverings as mats; (2) entrapment of sediment grains within and between networks of rhizoids; (3) grain entwining and adherence by rhizoids, through mucilage secretions, biofilm-like envelopment of thalli on surface grains; and (4) through grain entrapment within upright 'leafy' structures. Significantly, μCT imaging allows us to ascertain that rhizoids are the main method for entrapment and stabilisation of soil grains in the thalloid liverworts. This information provides us with details of how the earliest land plants may have significantly influenced early Palaeozoic sedimentary system architectures, promoted in situ weathering and proto-soil development, and how these interactions diversified over time with the evolution of new plant organ systems. Further, this study highlights the importance of cryptogamic organisms in the early stages of sediment stabilisation and soil formation today.
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Affiliation(s)
- Ria L Mitchell
- Science Group, The Natural History Museum, London, UK
- Sheffield Tomography Centre (STC), Kroto Research Institute, The University of Sheffield, Sheffield, UK
| | - Paul Kenrick
- Science Group, The Natural History Museum, London, UK
| | | | - Jeff Duckett
- Science Group, The Natural History Museum, London, UK
| | - Christine Strullu-Derrien
- Science Group, The Natural History Museum, London, UK
- Institut de Systématique, Evolution, Biodiversité (ISYEB), UMR7205, Muséum National d'Histoire naturelle, Sorbonne Université, CNRS, Paris, France
| | - Neil Davies
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - William J McMahon
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
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4
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Motte H, Fang T, Parizot B, Smet W, Yang X, Poelmans W, Walker L, Njo M, Bassel GW, Beeckman T. Cellular and gene expression patterns associated with root bifurcation in Selaginella. PLANT PHYSIOLOGY 2022; 190:2398-2416. [PMID: 36029252 PMCID: PMC9706437 DOI: 10.1093/plphys/kiac402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
The roots of lycophytes branch through dichotomy or bifurcation, during which the root apex splits into two daughter roots. This is morphologically distinct from lateral root (LR) branching in the extant euphyllophytes, with LRs developing along the root axis at different distances from the apex. Although the process of root bifurcation is poorly understood, such knowledge can be important, because it may represent an evolutionarily ancient strategy that roots recruited to form new stem cells or meristems. In this study, we examined root bifurcation in the lycophyte Selaginella moellendorffii. We characterized an in vitro developmental time frame based on repetitive apex bifurcations, allowing us to sample different stages of dichotomous root branching and analyze the root meristem and root branching in S. moellendorffii at the microscopic and transcriptomic level. Our results showed that, in contrast to previous assumptions, initial cells (ICs) in the root meristem are mostly not tetrahedral but rather show an irregular shape. Tracking down the early stages of root branching argues for the occurrence of a symmetric division of the single IC, resulting in two apical stem cells that initiate root meristem bifurcation. Moreover, we generated a S. moellendorffii root branching transcriptome that resulted in the delineation of a subset of core meristem genes. The occurrence of multiple putative orthologs of meristem genes in this dataset suggests the presence of conserved pathways in the control of meristem and root stem cell establishment or maintenance.
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Affiliation(s)
- Hans Motte
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Tao Fang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Boris Parizot
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Wouter Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Xilan Yang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Ward Poelmans
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Liam Walker
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Maria Njo
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - George W Bassel
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
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5
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Ito Y, Fujinami R, Imaichi R, Yamada T. Shared body plans of lycophytes inferred from root formation of Lycopodium clavatum. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.930167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Late Silurian to early Devonian lycophytes had prostrate aerial axes, while subordinate organs or subterranean axes were formed around the dichotomies of the axes. The subterranean axes are hypothesized to have evolved into root-bearing axes (rhizophores) and roots in extant Selaginellaceae and Lycopodiaceae, respectively. Consistent with this hypothesis, rhizophores are formed on the dichotomies of shoots in Selaginellaceae. However, it has remained unclear whether roots are borne in the same position in Lycopodiaceae. In addition, roots form endogenously in the stem, but no data are available regarding the tissues in stem from which they arise. In this study, we tracked the root development in the clubmoss, Lycopodium clavatum, based on anatomical sections and 3D reconstructed images. The vascular tissue of the stem is encircled by ground meristem, which supplies cortical cells outwardly by periclinal divisions. A linear parenchymatous tissue is present on the ventral side of vascular cylinder, which we call “ventral tissue” in this study. We found that root primordia are formed endogenously on the ventral side of stem, possibly from the ventral tissue. In addition, roots always initiate at positions close to dichotomies of stem. The root-initiating position supports the suggestion that Lycopodium roots share a body plan with the subterranean organs of the hypothesized ancestry.
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6
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Gurung K, Field KJ, Batterman SA, Goddéris Y, Donnadieu Y, Porada P, Taylor LL, Mills BJW. Climate windows of opportunity for plant expansion during the Phanerozoic. Nat Commun 2022; 13:4530. [PMID: 35927259 PMCID: PMC9352767 DOI: 10.1038/s41467-022-32077-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 07/15/2022] [Indexed: 11/08/2022] Open
Abstract
Earth's long-term climate may have profoundly influenced plant evolution. Local climatic factors, including water availability, light, and temperature, play a key role in plant physiology and growth, and have fluctuated substantially over geological time. However, the impact of these key climate variables on global plant biomass across the Phanerozoic has not yet been established. Linking climate and dynamic vegetation modelling, we identify two key 'windows of opportunity' during the Ordovician and Jurassic-Paleogene capable of supporting dramatic expansions of potential plant biomass. These conditions are driven by continental dispersion, paleolatitude of continental area and a lack of glaciation, allowing for an intense hydrological cycle and greater water availability. These windows coincide with the initial expansion of land plants and the later angiosperm radiation. Our findings suggest that the timing and expansion of habitable space for plants played an important role in plant evolution and diversification.
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Affiliation(s)
- Khushboo Gurung
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds, LS2 9JT, UK.
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK.
| | - Katie J Field
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Sarah A Batterman
- Cary Institute of Ecosystem Studies, Millbrook, NY, 12545, USA
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
- Smithsonian Tropical Research Institute, Ancon, Panama
| | - Yves Goddéris
- Géosciences Environnement Toulouse, CNRS-Université de Toulouse III, Toulouse, France
| | - Yannick Donnadieu
- CEREGE, Aix Marseille Univ, CNRS, IRD, INRA, Coll France, Aix-en-Provence, France
| | - Philipp Porada
- Institute of Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Lyla L Taylor
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Benjamin J W Mills
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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7
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Wu X, Yuan F, Wang X, Zhu S, Pei ZM. Evolution of osmosensing OSCA1 Ca 2+ channel family coincident with plant transition from water to land. THE PLANT GENOME 2022; 15:e20198. [PMID: 35502648 DOI: 10.1002/tpg2.20198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Water is crucial to plant growth, development, and environmental adaptation. Water stress triggers cytosolic Ca2+ ([Ca2+ ]i ) increases, and the osmosensor OSCA1 (REDUCED-HYPEROSMOLALITY-INDUCED-[Ca2+ ]i -INCREASE 1), a member of the OSCA family, perceives the initial water stress and governs its downstream responses. OSCA homologs exist in eukaryotes and largely radiate in higher plants. However, it is enigmatic whether the OSCA family is crucial for plant evolution from aqueous to terrestrial environments and for the subsequent adaptation on land. Here, we carried out the first phylogenetic and molecular evolutionary analyses of the OSCA family. The family originated and diversified during the early evolution of protists, and three more lineages were established (a) in plants, (b) in fungi, and (c) in a complex clade of several major eukaryotic lineages. The chlorophyte algal cluster is directly basal to streptophyte-specific Clades 1-3, consistent with plant transition from water to land. The Clades 1-3 present different gene expansion pattern and together with previous functional analysis of OSCAs reveal that they probably have evolved diverse functions in respond to various mechanical stresses during the independent evolution of land plant clades. Moreover, variable selection pressures on different land plant lineages were explored. OSCAs in early land plants (mosses and lycophytes) were under decelerated evolution, whereas OSCAs in seed plants showed accelerated evolution. Together, we hypothesize OSCAs have evolved to sense water stress in the ancestor of euphyllophytes, which occupies typical leaves, typical roots, and phloem tissues, all of which require osmosensors to maintain water balance and food conduction through plant bodies.
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Affiliation(s)
- Xiaomei Wu
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
- Dep. of Biology, Duke Univ., Durham, NC, 27708, USA
| | - Fang Yuan
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
- Dep. of Biology, Duke Univ., Durham, NC, 27708, USA
| | - Xuewen Wang
- Center for Human Identification, Univ. of North Texas Health Science Center, Fort Worth, TX, 76107, USA
| | - Shan Zhu
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
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8
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Buatois LA, Davies NS, Gibling MR, Krapovickas V, Labandeira CC, MacNaughton RB, Mángano MG, Minter NJ, Shillito AP. The Invasion of the Land in Deep Time: Integrating Paleozoic Records of Paleobiology, Ichnology, Sedimentology, and Geomorphology. Integr Comp Biol 2022; 62:297-331. [PMID: 35640908 DOI: 10.1093/icb/icac059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/19/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The invasion of the land was a complex, protracted process, punctuated by mass extinctions, that involved multiple routes from marine environments. We integrate paleobiology, ichnology, sedimentology, and geomorphology to reconstruct Paleozoic terrestrialization. Cambrian landscapes were dominated by laterally mobile rivers with unstable banks in the absence of significant vegetation. Temporary incursions by arthropods and worm-like organisms into coastal environments apparently did not result in establishment of continental communities. Contemporaneous lacustrine faunas may have been inhibited by limited nutrient delivery and high sediment loads. The Ordovician appearance of early land plants triggered a shift in the primary locus of the global clay mineral factory, increasing the amount of mudrock on the continents. The Silurian-Devonian rise of vascular land plants, including the first forests and extensive root systems, was instrumental in further retaining fine sediment on alluvial plains. These innovations led to increased architectural complexity of braided and meandering rivers. Landscape changes were synchronous with establishment of freshwater and terrestrial arthropod faunas in overbank areas, abandoned fluvial channels, lake margins, ephemeral lakes, and inland deserts. Silurian-Devonian lakes experienced improved nutrient availability, due to increased phosphate weathering and terrestrial humic matter. All these changes favoured frequent invasions to permament establishment of jawless and jawed fishes in freshwater habitats and the subsequent tetrapod colonization of the land. The Carboniferous saw rapid diversification of tetrapods, mostly linked to aquatic reproduction, and land plants, including gymnosperms. Deeper root systems promoted further riverbank stabilization, contributing to the rise of anabranching rivers and braided systems with vegetated islands. New lineages of aquatic insects developed and expanded novel feeding modes, including herbivory. Late Paleozoic soils commonly contain pervasive root and millipede traces. Lacustrine animal communities diversified, accompanied by increased food-web complexity and improved food delivery which may have favored permanent colonization of offshore and deep-water lake environments. These trends continued in the Permian, but progressive aridification favored formation of hypersaline lakes, which were stressful for colonization. The Capitanian and end-Permian extinctions affected lacustrine and fluvial biotas, particularly the invertebrate infauna, although burrowing may have allowed some tetrapods to survive associated global warming and increased aridification.
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Affiliation(s)
- Luis A Buatois
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Neil S Davies
- Department of Earth Sciences, University of Cambridge, Cambridge, Cambridgeshire CB2 3EQ, UK
| | - Martin R Gibling
- Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Verónica Krapovickas
- Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Argentina
| | - Conrad C Labandeira
- Department of Paleobiology, Smithsonian Institution, Washington DC 20013-7012, USA.,Department of Entomology and BEES Program, University of Maryland, College Park, Maryland 21740, USA.,College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Robert B MacNaughton
- Geological Survey of Canada (Calgary), Natural Resources Canada, Calgary, Alberta T2L 2A7, Canada
| | - M Gabriela Mángano
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Nicholas J Minter
- School of the Environment, Geography, and Geosciences, University of Portsmouth, Portsmouth, Hampshire PO1 3QL, UK
| | - Anthony P Shillito
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, UK
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9
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Fang T, Motte H, Parizot B, Beeckman T. Early "Rootprints" of Plant Terrestrialization: Selaginella Root Development Sheds Light on Root Evolution in Vascular Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:735514. [PMID: 34671375 PMCID: PMC8521068 DOI: 10.3389/fpls.2021.735514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
Roots provide multiple key functions for plants, including anchorage and capturing of water and nutrients. Evolutionarily, roots represent a crucial innovation that enabled plants to migrate from aquatic to terrestrial environment and to grow in height. Based on fossil evidence, roots evolved at least twice independently, once in the lycophyte clade and once in the euphyllophyte (ferns and seed plants) clade. In lycophytes, roots originated in a stepwise manner. Despite their pivotal position in root evolution, it remains unclear how root development is controlled in lycophytes. Getting more insight into lycophyte root development might shed light on how genetic players controlling the root meristem and root developmental processes have evolved. Unfortunately, genetic studies in lycophytes are lagging behind, lacking advanced biotechnological tools, partially caused by the limited economic value of this clade. The technology of RNA sequencing (RNA-seq) at least enabled transcriptome studies, which could enhance the understanding or discovery of genes involved in the root development of this sister group of euphyllophytes. Here, we provide an overview of the current knowledge on root evolution followed by a survey of root developmental events and how these are genetically and hormonally controlled, starting from insights obtained in the model seed plant Arabidopsis and where possible making a comparison with lycophyte root development. Second, we suggest possible key genetic regulators in root development of lycophytes mainly based on their expression profiles in Selaginella moellendorffii and phylogenetics. Finally, we point out challenges and possible future directions for research on root evolution.
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Affiliation(s)
- Tao Fang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Hans Motte
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Boris Parizot
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
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10
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Hetherington AJ, Bridson SL, Lee Jones A, Hass H, Kerp H, Dolan L. An evidence-based 3D reconstruction of Asteroxylon mackiei, the most complex plant preserved from the Rhynie chert. eLife 2021; 10:e69447. [PMID: 34425940 PMCID: PMC8384418 DOI: 10.7554/elife.69447] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/05/2021] [Indexed: 01/16/2023] Open
Abstract
The Early Devonian Rhynie chert preserves the earliest terrestrial ecosystem and informs our understanding of early life on land. However, our knowledge of the 3D structure, and development of these plants is still rudimentary. Here we used digital 3D reconstruction techniques to produce the first well-evidenced reconstruction of the structure and development of the rooting system of the lycopsid Asteroxylon mackiei, the most complex plant in the Rhynie chert. The reconstruction reveals the organisation of the three distinct axis types - leafy shoot axes, root-bearing axes, and rooting axes - in the body plan. Combining this reconstruction with developmental data from fossilised meristems, we demonstrate that the A. mackiei rooting axis - a transitional lycophyte organ between the rootless ancestral state and true roots - developed from root-bearing axes by anisotomous dichotomy. Our discovery demonstrates how this unique organ developed and highlights the value of evidence-based reconstructions for understanding the development and evolution of the first complex vascular plants on Earth.
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Affiliation(s)
| | - Siobhán L Bridson
- Department of Plant Sciences, University of OxfordOxfordUnited Kingdom
| | - Anna Lee Jones
- Department of Plant Sciences, University of OxfordOxfordUnited Kingdom
- Department of Plant Sciences, University of CambridgeCambridgeUnited Kingdom
| | - Hagen Hass
- Research Group for Palaeobotany, Institute for Geology and Palaeontology, Westfälische Wilhelms-Universität MünsterMünsterGermany
| | - Hans Kerp
- Research Group for Palaeobotany, Institute for Geology and Palaeontology, Westfälische Wilhelms-Universität MünsterMünsterGermany
| | - Liam Dolan
- Department of Plant Sciences, University of OxfordOxfordUnited Kingdom
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11
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Fujinami R, Nakajima A, Imaichi R, Yamada T. Lycopodium root meristem dynamics supports homology between shoots and roots in lycophytes. THE NEW PHYTOLOGIST 2021; 229:460-468. [PMID: 32696978 DOI: 10.1111/nph.16814] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Roots have played a pivotal role in the conquest of land by vascular plants, yet their origin has remained enigmatic. Palaeobotanical evidence suggests that roots may have originated from subterranean shoots in some lycophyte species. If this hypothesis is correct, it would follow that the roots and shoots of extant lycophytes share fundamental developmental mechanisms. We tracked meristem dynamics in root and shoot apices of Lycopodium clavatum using a thymidine analogue and expression patterns of histone H4, respectively. Then we compared the meristem dynamics of roots and shoots to identify developmental similarities. Both apical meristems contained a quiescent tissue characterised by a low frequency of cell division. Actively dividing cells appeared in the quiescent tissue during dichotomous branching of both roots and shoots. As a result, the parental meristem divides into two daughter meristems, which give rise to new root or shoot apices. These striking similarities in meristem dynamics provide new neobotanical data that support the shoot-origin hypothesis of lycophyte roots. Although Lycopodium roots may have originated from subterranean shoots of Devonian lycophytes, these shoots may have changed into root-bearing axes in other extant lycophyte lineages.
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Affiliation(s)
- Rieko Fujinami
- Faculty of Education, Kyoto University of Education, 1 Fujinomori-cho, Fukakusa, Kyoto, 612-8522, Japan
| | - Atsuko Nakajima
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Ryoko Imaichi
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Toshihiro Yamada
- Botanical Gardens, Faculty of Science, Osaka City University, Kisaichi, Katano, Osaka, 576-0004, Japan
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12
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Fujinami R, Yamada T, Imaichi R. Root apical meristem diversity and the origin of roots: insights from extant lycophytes. JOURNAL OF PLANT RESEARCH 2020; 133:291-296. [PMID: 32002717 DOI: 10.1007/s10265-020-01167-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
The independent origin of roots in lycophytes and euphyllophytes has been proposed, mainly based on paleobotanical records. However, the question of how roots evolved within these lineages remains unresolved. Root apical meristem (RAM) organization in lycophytes would provide a clue toward understanding the early evolution of roots. Recently, we examined RAM organization in lycophytes (Lycopodiaceae, Isoetaceae, and Selaginellaceae) in terms of cell division activity and anatomy, comparing RAM among vascular plants. Lycophyte RAM exhibited four organization types (I, II, III, and apical); thus, RAM organization in extant lycophytes was more diverse than expected. Type I RAM contained a region with very low cell division frequency, reminiscent of the quiescent center (QC) in seed plant RAM. Although some euphyllophyte RAMs were structurally similar to types II and III and apical cell-type RAM, lycophyte RAM of types II and III had no QC-like area. These results support the paleobotanical predictions that roots evolved several times in lycophytes, as well as in euphyllophytes. In this review, we also introduce recent findings on RAM organization in extant lycophytes and discuss the origin of roots in vascular plants.
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Affiliation(s)
- Rieko Fujinami
- Faculty of Education, Kyoto University of Education, 1 Fujinomori-cho, Fukakusa, Kyoto, 612-8522, Japan.
| | - Toshihiro Yamada
- Botanical Gardens, Faculty of Science, Osaka City University, Kisaichi, Katano, Osaka, 576-0004, Japan
| | - Ryoko Imaichi
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
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Motte H, Vanneste S, Beeckman T. Molecular and Environmental Regulation of Root Development. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:465-488. [PMID: 30822115 DOI: 10.1146/annurev-arplant-050718-100423] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In order to optimally establish their root systems, plants are endowed with several mechanisms to use at distinct steps during their development. In this review, we zoom in on the major processes involved in root development and detail important new insights that have been generated in recent studies, mainly using the Arabidopsis root as a model. First, we discuss new insights in primary root development with the characterization of tissue-specific transcription factor complexes and the identification of non-cell-autonomous control mechanisms in the root apical meristem. Next, root branching is discussed by focusing on the earliest steps in the development of a new lateral root and control of its postemergence growth. Finally, we discuss the impact of phosphate, nitrogen, and water availability on root development and summarize current knowledge about the major molecular mechanisms involved.
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Affiliation(s)
- Hans Motte
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
| | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
- Lab of Plant Growth Analysis, Ghent University Global Campus, Incheon 21985, Republic of Korea
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
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Hetherington AJ, Dolan L. Rhynie chert fossils demonstrate the independent origin and gradual evolution of lycophyte roots. CURRENT OPINION IN PLANT BIOLOGY 2019; 47:119-126. [PMID: 30562673 DOI: 10.1016/j.pbi.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 12/03/2018] [Accepted: 12/04/2018] [Indexed: 05/13/2023]
Abstract
Mapping fossil traits onto the land plant phylogenetic framework indicates that there were at least two independent origins of roots among extant vascular plants - once in lycophytes and independently in euphyllophytes. At least two rooting structural types are found among extinct species preserved in the Rhynie chert. First, species that lacked roots and developed horizontal axes that developed rhizoids. Second, the rooting axes of Asteroxylon mackiei resembled the roots of extant lycopsids but lacked root hairs and root caps. These two rooting structures preceded the evolution of the roots of extant lycophytes comprising axes on which root hairs and root caps developed. These data demonstrate the defining root characters evolved gradually in the lycophyte lineage.
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Affiliation(s)
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
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15
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16
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Imaichi R, Moritoki N, Solvang HK. Evolution of root apical meristem structures in vascular plants: plasmodesmatal networks. AMERICAN JOURNAL OF BOTANY 2018; 105:1453-1468. [PMID: 30179250 DOI: 10.1002/ajb2.1153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY The apical meristem generates indeterminate apical growth of the stem and root of vascular plants. Our previous examination showed that shoot apical meristems (SAMs) can be classified into two types based on plasmodesmatal networks (PNs), which are important elements in symplasmic signaling pathways within the apical meristem. Here, we examined the PNs of root apical meristems (RAMs) in comparison with those of SAMs. METHODS Root apical meristems of 18 families and 22 species of lycophytes and euphyllophytes were analyzed. Plasmodesmata (PD) in cell walls in median longitudinal sections of RAMs were enumerated using transmission electron micrographs, and the PD density per 1 μm2 of each cell wall was calculated. KEY RESULTS Root apical meristems with prominent apical cells of monilophytes (euphyllophytes) and Selaginellaceae (lycophytes) had high PD densities, while RAMs with plural initial cells of gymnosperms and angiosperms (euphyllophytes), and of Lycopodiaceae and Isoetaceae (lycophytes) had low PD densities. This correlation between structures of apical meristems and PD densities is identical to that in SAMs already described. CONCLUSIONS Irrespective of their diversified structures, the RAMs of vascular plants can be classified into two types with respect to PNs: the fern (monilophyte) type, which has a lineage-specific PN with only primary PD, and the seed-plant type, which has an interspecific PN with secondary PD in addition to primary PD. PNs may have played a key role in the evolution of apical meristems in vascular plants.
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Affiliation(s)
- Ryoko Imaichi
- Department of Chemical and Biological Sciences, Japan Women's University, 8-1, Mejirodai 2-chome, Tokyo, 112-8681, Japan
| | - Nobuko Moritoki
- Laboratory of Electron Microscopy, Japan Women's University, 8-1, Mejirodai 2-chome, Tokyo, 112-8681, Japan
| | - Hiroko Kato Solvang
- Marine Mammals Research Group, Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817, Bergen, Norway
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17
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Abstract
Roots are one of the three fundamental organ systems of vascular plants1, and have roles in anchorage, symbiosis, and nutrient and water uptake2-4. However, the fragmentary nature of the fossil record obscures the origins of roots and makes it difficult to identify when the sole defining characteristic of extant roots-the presence of self-renewing structures called root meristems that are covered by a root cap at their apex1-9-evolved. Here we report the discovery of what are-to our knowledge-the oldest meristems of rooting axes, found in the earliest-preserved terrestrial ecosystem10 (the 407-million-year-old Rhynie chert). These meristems, which belonged to the lycopsid Asteroxylon mackiei11-14, lacked root caps and instead developed a continuous epidermis over the surface of the meristem. The rooting axes and meristems of A. mackiei are unique among vascular plants. These data support the hypothesis that roots, as defined in extant vascular plants by the presence of a root cap7, were a late innovation in the vascular lineage. Roots therefore acquired traits in a stepwise fashion. The relatively late origin in lycophytes of roots with caps is consistent with the hypothesis that roots evolved multiple times2 rather than having a single origin1, and the extensive similarities between lycophyte and euphyllophyte roots15-18 therefore represent examples of convergent evolution. The key phylogenetic position of A. mackiei-with its transitional rooting organ-between early diverging land plants that lacked roots and derived plants that developed roots demonstrates how roots were 'assembled' during the course of plant evolution.
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18
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McMahon WJ, Davies NS. Evolution of alluvial mudrock forced by early land plants. Science 2018; 359:1022-1024. [DOI: 10.1126/science.aan4660] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/26/2017] [Accepted: 01/16/2018] [Indexed: 11/02/2022]
Affiliation(s)
- William J. McMahon
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Neil S. Davies
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
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19
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Raven JA. Evolution and palaeophysiology of the vascular system and other means of long-distance transport. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160497. [PMID: 29254962 PMCID: PMC5745333 DOI: 10.1098/rstb.2016.0497] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2017] [Indexed: 12/13/2022] Open
Abstract
Photolithotrophic growth on land using atmospheric CO2 inevitably involves H2O vapour loss. Embryophytes greater than or equal to 100 mm tall are homoiohydric and endohydric with mass flow of aqueous solution through the xylem in tracheophytes. Structural details in Rhynie sporophytes enable modelling of the hydraulics of H2O supply to the transpiring surface, and the potential for gas exchange with the Devonian atmosphere. Xylem carrying H2O under tension involves programmed cell death, rigid cell walls and embolism repair; fossils provide little evidence on these functions other than the presence of lignin. The phenylalanine ammonia lyase essential for lignin synthesis came from horizontal gene transfer. Rhynie plants lack endodermes, limiting regulation of the supply of soil nutrients to shoots. The transfer of organic solutes from photosynthetic sites to growing and storage tissues involves mass flow through phloem in extant tracheophytes. Rhynie plants show little evidence of phloem; possible alternatives for transport of organic solutes are discussed. Extant examples of the arbuscular mycorrhizas found in Rhynie plants exchange soil-derived nutrients (especially P) for plant-derived organic matter, involving bidirectional mass flow along the hyphae. The aquatic cyanobacteria and the charalean Palaeonitella at Rhynie also have long-distance (relative to the size of the organism) transport.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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20
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Augstein F, Carlsbecker A. Getting to the Roots: A Developmental Genetic View of Root Anatomy and Function From Arabidopsis to Lycophytes. FRONTIERS IN PLANT SCIENCE 2018; 9:1410. [PMID: 30319672 PMCID: PMC6167918 DOI: 10.3389/fpls.2018.01410] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 09/05/2018] [Indexed: 05/11/2023]
Abstract
Roots attach plants to the ground and ensure efficient and selective uptake of water and nutrients. These functions are facilitated by the morphological and anatomical structures of the root, formed by the activity of the root apical meristem (RAM) and consecutive patterning and differentiation of specific tissues with distinct functions. Despite the importance of this plant organ, its evolutionary history is not clear, but fossils suggest that roots evolved at least twice, in the lycophyte (clubmosses and their allies) and in the euphyllophyte (ferns and seed plants) lineages. Both lycophyte and euphyllophyte roots grow indeterminately by the action of an apical meristem, which is protected by a root cap. They produce root hairs, and in most species the vascular stele is guarded by a specialized endodermal cell layer. Hence, most of these traits must have evolved independently in these lineages. This raises the question if the development of these apparently analogous tissues is regulated by distinct or homologous genes, independently recruited from a common ancestor of lycophytes and euphyllophytes. Currently, there are few studies of the genetic and molecular regulation of lycophyte and fern roots. Therefore, in this review, we focus on key regulatory networks that operate in root development in the model angiosperm Arabidopsis. We describe current knowledge of the mechanisms governing RAM maintenance as well as patterning and differentiation of tissues, such as the endodermis and the vasculature, and compare with other species. We discuss the importance of comparative analyses of anatomy and morphology of extant and extinct species, along with analyses of gene regulatory networks and, ultimately, gene function in plants holding key phylogenetic positions to test hypotheses of root evolution.
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21
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Matsunaga KKS, Cullen NP, Tomescu AMF. Vascularization of the Selaginella rhizophore: anatomical fingerprints of polar auxin transport with implications for the deep fossil record. THE NEW PHYTOLOGIST 2017; 216:419-428. [PMID: 28225170 DOI: 10.1111/nph.14478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/16/2017] [Indexed: 06/06/2023]
Abstract
The Selaginella rhizophore is a unique and enigmatic organ whose homology with roots, shoots, or neither of the two remains unresolved. Nevertheless, rhizophore-like organs have been documented in several fossil lycophytes. Here we test the homology of these organs through comparisons with the architecture of rhizophore vascularization in Selaginella. We document rhizophore vascularization in nine Selaginella species using cleared whole-mounts and histological sectioning combined with three-dimensional reconstruction. Three patterns of rhizophore vascularization are present in Selaginella and each is comparable to those observed in rhizophore-like organs of fossil lycophytes. More compellingly, we found that all Selaginella species sampled exhibit tracheids that arc backward from the stem and side branch into the rhizophore base. This tracheid curvature is consistent with acropetal auxin transport previously documented in the rhizophore and is indicative of the redirection of basipetal auxin from the shoot into the rhizophore during development. The tracheid curvature observed in Selaginella rhizophores provides an anatomical fingerprint for the patterns of auxin flow that underpin rhizophore development. Similar tracheid geometry may be present and should be searched for in fossils to address rhizophore homology and the conservation of auxin-related developmental mechanisms from early stages of lycophyte evolution.
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Affiliation(s)
- Kelly K S Matsunaga
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nevin P Cullen
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | - Alexandru M F Tomescu
- Department of Biological Sciences, Humboldt State University, Arcata, CA, 95521, USA
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22
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Wilson JP, Montañez IP, White JD, DiMichele WA, McElwain JC, Poulsen CJ, Hren MT. Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate. THE NEW PHYTOLOGIST 2017; 215:1333-1353. [PMID: 28742257 DOI: 10.1111/nph.14700] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/22/2017] [Indexed: 05/05/2023]
Abstract
Contents 1333 I. 1334 II. 1335 III. 1339 IV. 1344 V. 1347 VI. 1347 1348 1348 References 1348 SUMMARY: The Carboniferous, the time of Earth's penultimate icehouse and widespread coal formation, was dominated by extinct lineages of early-diverging vascular plants. Studies of nearest living relatives of key Carboniferous plants suggest that their physiologies and growth forms differed substantially from most types of modern vegetation, particularly forests. It remains a matter of debate precisely how differently and to what degree these long-extinct plants influenced the environment. Integrating biophysical analysis of stomatal and vascular conductivity with geochemical analysis of fossilized tissues and process-based ecosystem-scale modeling yields a dynamic and unique perspective on these paleoforests. This integrated approach indicates that key Carboniferous plants were capable of growth and transpiration rates that approach values found in extant crown-group angiosperms, differing greatly from comparatively modest rates found in their closest living relatives. Ecosystem modeling suggests that divergent stomatal conductance, leaf sizes and stem life span between dominant clades would have shifted the balance of soil-atmosphere water fluxes, and thus surface runoff flux, during repeated, climate-driven, vegetation turnovers. This synthesis highlights the importance of 'whole plant' physiological reconstruction of extinct plants and the potential of vascular plants to have influenced the Earth system hundreds of millions of years ago through vegetation-climate feedbacks.
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Affiliation(s)
| | - Isabel P Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - Joseph D White
- Department of Biology, Baylor University, Waco, TX, 76798, USA
| | - William A DiMichele
- Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC, 20560, USA
| | - Jennifer C McElwain
- Earth Institute, School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael T Hren
- Center for Integrative Geosciences, University of Connecticut, Storrs, CT, 06269, USA
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Alix K, Gérard PR, Schwarzacher T, Heslop-Harrison JS(P. Polyploidy and interspecific hybridization: partners for adaptation, speciation and evolution in plants. ANNALS OF BOTANY 2017; 120:183-194. [PMID: 28854567 PMCID: PMC5737848 DOI: 10.1093/aob/mcx079] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 05/31/2017] [Indexed: 05/15/2023]
Abstract
BACKGROUND Polyploidy or whole-genome duplication is now recognized as being present in almost all lineages of higher plants, with multiple rounds of polyploidy occurring in most extant species. The ancient evolutionary events have been identified through genome sequence analysis, while recent hybridization events are found in about half of the world's crops and wild species. Building from this new paradigm for understanding plant evolution, the papers in this Special Issue address questions about polyploidy in ecology, adaptation, reproduction and speciation of wild and cultivated plants from diverse ecosystems. Other papers, including this review, consider genomic aspects of polyploidy. APPROACHES Discovery of the evolutionary consequences of new, evolutionarily recent and ancient polyploidy requires a range of approaches. Large-scale studies of both single species and whole ecosystems, with hundreds to tens of thousands of individuals, sometimes involving 'garden' or transplant experiments, are important for studying adaptation. Molecular studies of genomes are needed to measure diversity in genotypes, showing ancestors, the nature and number of polyploidy and backcross events that have occurred, and allowing analysis of gene expression and transposable element activation. Speciation events and the impact of reticulate evolution require comprehensive phylogenetic analyses and can be assisted by resynthesis of hybrids. In this Special Issue, we include studies ranging in scope from experimental and genomic, through ecological to more theoretical. CONCLUSIONS The success of polyploidy, displacing the diploid ancestors of almost all plants, is well illustrated by the huge angiosperm diversity that is assumed to originate from recurrent polyploidization events. Strikingly, polyploidization often occurred prior to or simultaneously with major evolutionary transitions and adaptive radiation of species, supporting the concept that polyploidy plays a predominant role in bursts of adaptive speciation. Polyploidy results in immediate genetic redundancy and represents, with the emergence of new gene functions, an important source of novelty. Along with recombination, gene mutation, transposon activity and chromosomal rearrangement, polyploidy and whole-genome duplication act as drivers of evolution and divergence in plant behaviour and gene function, enabling diversification, speciation and hence plant evolution.
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Affiliation(s)
- Karine Alix
- GQE – Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
- For correspondence. E-mail
| | - Pierre R. Gérard
- GQE – Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Trude Schwarzacher
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
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Fujinami R, Yamada T, Nakajima A, Takagi S, Idogawa A, Kawakami E, Tsutsumi M, Imaichi R. Root apical meristem diversity in extant lycophytes and implications for root origins. THE NEW PHYTOLOGIST 2017; 215:1210-1220. [PMID: 28585243 DOI: 10.1111/nph.14630] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/25/2017] [Indexed: 05/25/2023]
Abstract
Root apical meristem (RAM) organization in lycophytes could be a key to understanding the early evolution of roots, but this topic has been insufficiently explored. We examined the RAM organization of lycophytes in terms of cell division activities and anatomies, and compared RAMs among vascular plants. RAMs of 13 species of lycophytes were semi-thin-sectioned and observed under a light microscope. Furthermore, the frequency of cell division in the RAM of species was analyzed using thymidine analogs. RAMs of lycophytes exhibited four organization types: type I (Lycopodium and Diphasiastrum), II (Huperzia and Lycopodiella), III (Isoetes) and RAM with apical cell (Selaginella). The type I RAM found in Lycopodium had a region with a very low cell division frequency, reminiscent of the quiescent center (QC) in angiosperm roots. This is the first clear indication that a QC-like region is present in nonseed plants. At least four types of RAM are present in extant lycophytes, suggesting that RAM organization is more diverse than expected. Our results support the paleobotanical hypothesis that roots evolved several times in lycophytes, as well as in euphyllophytes.
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Affiliation(s)
- Rieko Fujinami
- Faculty of Education, Kyoto University of Education, 1 Fujinomori-cho, Fukakusa, Kyoto, 612-8522, Japan
| | - Toshihiro Yamada
- Faculty of Natural System, Institute of Science and Engineering, Kanazawa University, Kakuma, Ishikawa, 920-1192, Japan
| | - Atsuko Nakajima
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Shoko Takagi
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Ai Idogawa
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Eri Kawakami
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Maiko Tsutsumi
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
| | - Ryoko Imaichi
- Department of Chemical and Biological Sciences, Japan Women's University, Mejirodai, Tokyo, 112-8681, Japan
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25
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Hetherington AJ, Dolan L. The evolution of lycopsid rooting structures: conservatism and disparity. THE NEW PHYTOLOGIST 2017; 215:538-544. [PMID: 27901273 DOI: 10.1111/nph.14324] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/16/2016] [Indexed: 05/25/2023]
Abstract
Contents 538 I. 538 II. 539 III. 541 IV. 542 543 References 543 SUMMARY: The evolution of rooting structures was a crucial event in Earth's history, increasing the ability of plants to extract water, mine for nutrients and anchor above-ground shoot systems. Fossil evidence indicates that roots evolved at least twice among vascular plants, in the euphyllophytes and independently in the lycophytes. Here, we review the anatomy and evolution of lycopsid rooting structures. Highlighting recent discoveries made with fossils we suggest that the evolution of lycopsid rooting structures displays two contrasting patterns - conservatism and disparity. The structures termed roots have remained structurally similar despite hundreds of millions of years of evolution - an example of remarkable conservatism. By contrast, and over the same time period, the organs that give rise to roots have diversified, resulting in the evolution of numerous novel and disparate organs.
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Affiliation(s)
- Alexander J Hetherington
- Department of Plant Sciences, University of Oxford, Oxford South Parks Road, Oxford, OX1 3RB, UK
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, Oxford South Parks Road, Oxford, OX1 3RB, UK
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26
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Matsunaga KKS, Tomescu AMF. An organismal concept for Sengelia radicans gen. et sp. nov. - morphology and natural history of an Early Devonian lycophyte. ANNALS OF BOTANY 2017; 119:1097-1113. [PMID: 28334100 PMCID: PMC5604611 DOI: 10.1093/aob/mcw277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS Fossil plants are found as fragmentary remains and understanding them as natural species requires assembly of whole-organism concepts that integrate different plant parts. Such concepts are essential for incorporating fossils in hypotheses of plant evolution and phylogeny. Plants of the Early Devonian are crucial to reconstructing the initial radiation of tracheophytes, yet few are understood as whole organisms. METHODS This study assembles a whole-plant concept for the Early Devonian lycophyte Sengelia radicans gen. et sp. nov., based on morphometric data and taphonomic observations from >1000 specimens collected in the Beartooth Butte Formation (Wyoming, USA). KEY RESULTS Sengelia radicans occupies a key position between stem-group and derived lycophyte lineages. Sengelia had a rooting system of downward-growing root-bearing stems, formed dense monotypic mats of prostrate shoots in areas that experienced periodic flooding, and was characterized by a life-history strategy adapted for survival after floods, dominated by clonality, and featuring infrequent sexual reproduction. CONCLUSIONS Sengelia radicans is the oldest among the very few early tracheophytes for which a detailed, rigorous whole-plant concept integrates morphology, growth habit, life history and growth environment. This plant adds to the diversity of body plans documented among lycophytes and may help elucidate patterns of morphological evolution in the clade.
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Affiliation(s)
- Kelly K. S. Matsunaga
- For correspondence. Present address: University of Michigan, Department of Earth and Environmental Sciences, Ann Arbor, MI, USA. E-mail
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27
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Xue J, Deng Z, Huang P, Huang K, Benton MJ, Cui Y, Wang D, Liu J, Shen B, Basinger JF, Hao S. Belowground rhizomes in paleosols: The hidden half of an Early Devonian vascular plant. Proc Natl Acad Sci U S A 2016; 113:9451-6. [PMID: 27503883 PMCID: PMC5003246 DOI: 10.1073/pnas.1605051113] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant-soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils within a seasonal wet-dry climate zone. Rhizome networks contributed to the accumulation and pedogenesis of floodplain sediments and increased the soil stabilizing effects of early plants. Predating the appearance of trees with deep roots in the Middle Devonian, plant rhizomes have long functioned in the belowground soil ecosystem. This study presents strong, direct evidence for plant-soil interactions at an early stage of vascular plant radiation. Soil stabilization by complex rhizome systems was apparently widespread, and contributed to landscape modification at an earlier time than had been appreciated.
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Affiliation(s)
- Jinzhuang Xue
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China; Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China;
| | - Zhenzhen Deng
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Pu Huang
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Kangjun Huang
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Michael J Benton
- School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, United Kingdom
| | - Ying Cui
- Department of Earth Sciences, Dartmouth College, Hanover, NH 03755
| | - Deming Wang
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Jianbo Liu
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Bing Shen
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
| | - James F Basinger
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - Shougang Hao
- The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China
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