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Clark JW, Hetherington AJ, Morris JL, Pressel S, Duckett JG, Puttick MN, Schneider H, Kenrick P, Wellman CH, Donoghue PCJ. Evolution of phenotypic disparity in the plant kingdom. Nat Plants 2023; 9:1618-1626. [PMID: 37666963 PMCID: PMC10581900 DOI: 10.1038/s41477-023-01513-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 08/07/2023] [Indexed: 09/06/2023]
Abstract
The plant kingdom exhibits diverse bodyplans, from single-celled algae to complex multicellular land plants, but it is unclear how this phenotypic disparity was achieved. Here we show that the living divisions comprise discrete clusters within morphospace, separated largely by reproductive innovations, the extinction of evolutionary intermediates and lineage-specific evolution. Phenotypic complexity correlates not with disparity but with ploidy history, reflecting the role of genome duplication in plant macroevolution. Overall, the plant kingdom exhibits a pattern of episodically increasing disparity throughout its evolutionary history that mirrors the evolutionary floras and reflects ecological expansion facilitated by reproductive innovations. This pattern also parallels that seen in the animal and fungal kingdoms, suggesting a general pattern for the evolution of multicellular bodyplans.
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Affiliation(s)
- James W Clark
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK.
- School of Biological Sciences, University of Bristol, Bristol, UK.
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, UK.
| | - Alexander J Hetherington
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK.
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Jennifer L Morris
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK
| | | | | | - Mark N Puttick
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, UK
| | - Harald Schneider
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK
- The Natural History Museum, London, UK
- Center of Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | | | | | - Philip C J Donoghue
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, UK.
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2
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Hoysted GA, Field KJ, Sinanaj B, Bell CA, Bidartondo MI, Pressel S. Direct nitrogen, phosphorus and carbon exchanges between Mucoromycotina 'fine root endophyte' fungi and a flowering plant in novel monoxenic cultures. New Phytol 2023; 238:70-79. [PMID: 36739554 PMCID: PMC10952891 DOI: 10.1111/nph.18630] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 11/15/2022] [Indexed: 06/18/2023]
Abstract
Most plants form mycorrhizal associations with mutualistic soil fungi. Through these partnerships, resources are exchanged including photosynthetically fixed carbon for fungal-acquired nutrients. Recently, it was shown that the diversity of associated fungi is greater than previously assumed, extending to Mucoromycotina fungi. These Mucoromycotina 'fine root endophytes' (MFRE) are widespread and generally co-colonise plant roots together with Glomeromycotina 'coarse' arbuscular mycorrhizal fungi (AMF). Until now, this co-occurrence has hindered the determination of the direct function of MFRE symbiosis. To overcome this major barrier, we developed new techniques for fungal isolation and culture and established the first monoxenic in vitro cultures of MFRE colonising a flowering plant, clover. Using radio- and stable-isotope tracers in these in vitro systems, we measured the transfer of 33 P, 15 N and 14 C between MFRE hyphae and the host plant. Our results provide the first unequivocal evidence that MFRE fungi are nutritional mutualists with a flowering plant by showing that clover gained both 15 N and 33 P tracers directly from fungus in exchange for plant-fixed C in the absence of other micro-organisms. Our findings and methods pave the way for a new era in mycorrhizal research, firmly establishing MFRE as both mycorrhizal and functionally important in terrestrial ecosystems.
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Affiliation(s)
- Grace A. Hoysted
- Plants, Photosynthesis and Soil, School of BioscienceUniversity of SheffieldSheffieldS10 2TNUK
| | - Katie J. Field
- Plants, Photosynthesis and Soil, School of BioscienceUniversity of SheffieldSheffieldS10 2TNUK
| | - Besiana Sinanaj
- Plants, Photosynthesis and Soil, School of BioscienceUniversity of SheffieldSheffieldS10 2TNUK
| | | | - Martin I. Bidartondo
- Department of Life SciencesImperial College LondonLondonSW7 2AZUK
- Department of Ecosystem StewardshipRoyal Botanic Gardens, KewRichmondTW9 3DSUK
| | - Silvia Pressel
- Department of Life SciencesNatural History MuseumLondonSW7 5BDUK
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4
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Howard N, Pressel S, Kaye RS, Daniell TJ, Field KJ. The potential role of Mucoromycotina 'fine root endophytes' in plant nitrogen nutrition. Physiol Plant 2022; 174:e13715. [PMID: 35560043 PMCID: PMC9328347 DOI: 10.1111/ppl.13715] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/19/2022] [Accepted: 05/10/2022] [Indexed: 05/29/2023]
Abstract
Mycorrhizal associations between fungi and plant roots have globally significant impacts on nutrient cycling. Mucoromycotina 'fine root endophytes' (MFRE) are a distinct and recently characterised group of mycorrhiza-forming fungi that associate with the roots of a range of host plant species. Given their previous misidentification and assignment as arbuscular mycorrhizal fungi (AMF) of the Glomeromycotina, it is now important to untangle the specific form and function of MFRE symbioses. In particular, relatively little is known about the nature of MFRE colonisation and its role in N uptake and transfer to host plants. Even less is known about the mechanisms by which MFRE access and assimilate N, and how this N is processed and subsequently exchanged with host plants for photosynthates. Here, we summarise and contrast the structures formed by MFRE and arbuscular mycorrhizal fungi in host plants as well as compare the N source preference of each mycorrhizal fungal group with what is currently known for MFRE N uptake. We compare the mechanisms of N assimilation and transfer to host plants utilised by the main groups of mycorrhizal fungi and hypothesise potential mechanisms for MFRE N assimilation and transfer, outlining directions for future research.
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Affiliation(s)
- Nathan Howard
- Plants, Photosynthesis and Soil, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Silvia Pressel
- Department of Life SciencesNatural History MuseumLondonUK
| | - Ryan S. Kaye
- Plants, Photosynthesis and Soil, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Tim J. Daniell
- Plants, Photosynthesis and Soil, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Katie J. Field
- Plants, Photosynthesis and Soil, School of BiosciencesUniversity of SheffieldSheffieldUK
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5
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Edwards D, Morris JL, Axe L, Taylor WA, Duckett JG, Kenrick P, Pressel S. Earliest record of transfer cells in Lower Devonian plants. New Phytol 2022; 233:1456-1465. [PMID: 34806776 DOI: 10.1111/nph.17704] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Key sources of information on the nature of early terrestrial ecosystems are the fossilized remains of plants and associated organic encrustations, which are interpreted as either biofilms, biological soil crusts or lichens. The hypothesis that some of these encrustations might be the remains of the thalloid gametophytes of embryophytes provided the stimulus for this investigation. Fossils preserved in charcoal were extracted from Devonian Period (Lochkovian Stage, c. 410-419 Myr old) sediments at a geological site in Shropshire (UK). Scanning electron micrographs (SEMs) of the fossils were compared with new and published SEMs of extant bryophytes and tracheophytes, respectively. One specimen was further prepared and imaged by transmission electron microscopy. Fossils of thalloid morphology were composed almost entirely of cells with labyrinthine ingrowths; these also were present in fossils of axial morphology where they were associated with putative food-conducting cells. Comparison with modern embryophytes demonstrates that these distinctive cells are transfer cells (TCs). Our fossils provide by far the earliest geological evidence of TCs. They also show that some organic encrustations are the remains of thalloid land plants and that these are possibly part of the life cycle of a newly recognized group of plants called the eophytes.
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Affiliation(s)
- Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Jennifer L Morris
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Lindsey Axe
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Wilson A Taylor
- Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI, 54701-4004, USA
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Paul Kenrick
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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6
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Edwards D, Morris JL, Axe L, Duckett JG, Pressel S, Kenrick P. Piecing together the eophytes - a new group of ancient plants containing cryptospores. New Phytol 2022; 233:1440-1455. [PMID: 34806774 DOI: 10.1111/nph.17703] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
The earliest evidence for land plants comes from dispersed cryptospores from the Ordovician, which dominated assemblages for 60 million years. Direct evidence of their parent plants comes from minute fossils in Welsh Borderland Upper Silurian to Lower Devonian rocks. We recognize a group that had forking, striated axes with rare stomata terminating in valvate sporangia containing permanent cryptospores, but their anatomy was unknown especially regarding conducting tissues. Charcoalified fossils extracted from the rock using HF were selected from macerates and observed using scanning electron microscopy. Promising examples were split for further examination and compared with electron micrographs of the anatomy of extant bryophytes. Fertile fossil axes possess central elongate cells with thick walls bearing globules, occasional strands and plasmodesmata-sized pores. The anatomy of these cells best matches desiccation-tolerant food-conducting cells (leptoids) of bryophytes. Together with thick-walled epidermal cells and extremely small size, these features suggest that these plants were poikilohydric. Our new data on conducting cells confirms a combination of characters that distinguish the permanent cryptospore-producers from bryophytes and tracheophytes. We therefore propose the erection of a new group, here named the Eophytidae (eophytes).
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Affiliation(s)
- Dianne Edwards
- School of Earth and Environmental Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Jennifer L Morris
- School of Earth and Environmental Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Lindsey Axe
- School of Earth and Environmental Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Paul Kenrick
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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7
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Sinanaj B, Hoysted GA, Pressel S, Bidartondo MI, Field KJ. Critical research challenges facing Mucoromycotina 'fine root endophytes'. New Phytol 2021; 232:1528-1534. [PMID: 34411307 DOI: 10.1111/nph.17684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Besiana Sinanaj
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Grace A Hoysted
- Botany and Plant Science, School of Natural Sciences, National University of Ireland, Galway, H91 TK33, Ireland
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Martin I Bidartondo
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Katie J Field
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
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8
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Kubásek J, Hájek T, Duckett J, Pressel S, Šantrůček J. Erratum. New Phytol 2021; 231:2399. [PMID: 34337752 DOI: 10.1111/nph.17473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 05/14/2021] [Indexed: 06/13/2023]
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9
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Hoysted GA, Kowal J, Pressel S, Duckett JG, Bidartondo MI, Field KJ. Carbon for nutrient exchange between Lycopodiella inundata and Mucoromycotina fine root endophytes is unresponsive to high atmospheric CO 2. Mycorrhiza 2021; 31:431-440. [PMID: 33884466 PMCID: PMC8266774 DOI: 10.1007/s00572-021-01033-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/14/2021] [Indexed: 05/26/2023]
Abstract
Non-vascular plants associating with arbuscular mycorrhizal (AMF) and Mucoromycotina 'fine root endophyte' (MFRE) fungi derive greater benefits from their fungal associates under higher atmospheric [CO2] (a[CO2]) than ambient; however, nothing is known about how changes in a[CO2] affect MFRE function in vascular plants. We measured movement of phosphorus (P), nitrogen (N) and carbon (C) between the lycophyte Lycopodiella inundata and Mucoromycotina fine root endophyte fungi using 33P-orthophosphate, 15 N-ammonium chloride and 14CO2 isotope tracers under ambient and elevated a[CO2] concentrations of 440 and 800 ppm, respectively. Transfers of 33P and 15 N from MFRE to plants were unaffected by changes in a[CO2]. There was a slight increase in C transfer from plants to MFRE under elevated a[CO2]. Our results demonstrate that the exchange of C-for-nutrients between a vascular plant and Mucoromycotina FRE is largely unaffected by changes in a[CO2]. Unravelling the role of MFRE in host plant nutrition and potential C-for-N trade changes between symbionts under different abiotic conditions is imperative to further our understanding of the past, present and future roles of plant-fungal symbioses in ecosystems.
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Affiliation(s)
- Grace A Hoysted
- Deparment of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK.
| | - Jill Kowal
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Martin I Bidartondo
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Katie J Field
- Deparment of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
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10
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Kubásek J, Hájek T, Duckett J, Pressel S, Šantrůček J. Moss stomata do not respond to light and CO 2 concentration but facilitate carbon uptake by sporophytes: a gas exchange, stomatal aperture, and 13 C-labelling study. New Phytol 2021; 230:1815-1828. [PMID: 33458818 DOI: 10.1111/nph.17208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 01/07/2021] [Indexed: 05/06/2023]
Abstract
Stomata exert control on fluxes of CO2 and water (H2 O) in the majority of vascular plants and thus are pivotal for planetary fluxes of carbon and H2 O. However, in mosses, the significance and possible function of the sporophytic stomata are not well understood, hindering understanding of the ancestral function and evolution of these key structures of land plants. Infrared gas analysis and 13 CO2 labelling, with supporting data from gravimetry and optical and scanning electron microscopy, were used to measure CO2 assimilation and water exchange on young, green, ± fully expanded capsules of 11 moss species with a range of stomatal numbers, distributions, and aperture sizes. Moss sporophytes are effectively homoiohydric. In line with their open fixed apertures, moss stomata, contrary to those in tracheophytes, do not respond to light and CO2 concentration. Whereas the sporophyte cuticle is highly impermeable to gases, stomata are the predominant sites of 13 CO2 entry and H2 O loss in moss sporophytes, and CO2 assimilation is closely linked to total stomatal surface areas. Higher photosynthetic autonomy of moss sporophytes, consequent on the presence of numerous stomata, may have been the key to our understanding of evolution of large, gametophyte-independent sporophytes at the onset of plant terrestrialization.
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Affiliation(s)
- Jiří Kubásek
- Department of Experimental Plant Biology, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, 1760/31, Czech Republic
| | - Tomáš Hájek
- Department of Experimental Plant Biology, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, 1760/31, Czech Republic
| | - Jeffrey Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Jiří Šantrůček
- Department of Experimental Plant Biology, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, 1760/31, Czech Republic
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11
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Mitchell RL, Strullu-Derrien C, Sykes D, Pressel S, Duckett JG, Kenrick P. Cryptogamic ground covers as analogues for early terrestrial biospheres: Initiation and evolution of biologically mediated proto-soils. Geobiology 2021; 19:292-306. [PMID: 33569915 DOI: 10.1111/gbi.12431] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 05/29/2023]
Abstract
Modern cryptogamic ground covers (CGCs), comprising assemblages of bryophytes (hornworts, liverworts, mosses), fungi, bacteria, lichens and algae, are thought to resemble early divergent terrestrial communities. However, limited in situ plant and other fossils in the rock record, and a lack of CGC-like soils reported in the pre-Silurian sedimentological record, have hindered understanding of the structure, composition and interactions within the earliest CGCs. A key question is how the earliest CGC-like organisms drove weathering on primordial terrestrial surfaces (regolith), leading to the early stages of soil development as proto-soils, and subsequently contributing to large-scale biogeochemical shifts in the Earth System. Here, we employed a novel qualitative, quantitative and multi-dimensional imaging approach through X-ray micro-computed tomography, scanning electron, and optical microscopy to investigate whether different combinations of modern CGC organisms from primordial-like settings in Iceland develop organism-specific soil forming features at the macro- and micro-scales. Additionally, we analysed CGCs growing on hard rocky substrates to investigate the initiation of weathering processes non-destructively in 3D. We show that thalloid CGC organisms (liverworts, hornworts) develop thin organic layers at the surface (<1 cm) with limited subsurface structural development, whereas leafy mosses and communities of mixed organisms form profiles that are thicker (up to ~ 7 cm), structurally more complex, and more organic-rich. We term these thin layers and profiles proto-soils. Component analyses from X-ray micro-computed tomography data show that thickness and structure of these proto-soils are determined by the type of colonising organism(s), suggesting that the evolution of more complex soils through the Palaeozoic may have been driven by a shift in body plan of CGC-like organisms from flattened and appressed to upright and leafy. Our results provide a framework for identifying CGC-like proto-soils in the rock record and a new proxy for understanding organism-soil interactions in ancient terrestrial biospheres and their contribution to the early stages of soil formation.
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Affiliation(s)
- Ria L Mitchell
- Earth Sciences Department, The Natural History Museum, London, UK
- Sheffield Tomography Centre (STC), Kroto Research Institute, The University of Sheffield, Sheffield, UK
| | - Christine Strullu-Derrien
- Earth Sciences Department, The Natural History Museum, London, UK
- Institut de Systématique, Evolution, Biodiversité (ISYEB), UMR7205, Muséum National d'Histoire naturelle, Sorbonne Université, CNRS, Paris, France
| | - Dan Sykes
- Imaging and Analysis Centre (IAC), The Natural History Museum, London, UK
- Henry Moseley X-ray Imaging Facility, School of Materials, The Royce Institute, The University of Manchester, Manchester, UK
| | - Silvia Pressel
- Life Sciences Department, The Natural History Museum, London, UK
| | | | - Paul Kenrick
- Earth Sciences Department, The Natural History Museum, London, UK
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12
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Hoysted GA, Bidartondo MI, Duckett JG, Pressel S, Field KJ. Phenology and function in lycopod-Mucoromycotina symbiosis. New Phytol 2021; 229:2389-2394. [PMID: 33064903 DOI: 10.1111/nph.17009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/09/2020] [Indexed: 05/27/2023]
Affiliation(s)
- Grace A Hoysted
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Martin I Bidartondo
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Katie J Field
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
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13
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McAdam SAM, Duckett JG, Sussmilch FC, Pressel S, Renzaglia KS, Hedrich R, Brodribb TJ, Merced A. Stomata: the holey grail of plant evolution. Am J Bot 2021; 108:366-371. [PMID: 33687736 PMCID: PMC8175006 DOI: 10.1002/ajb2.1619] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/10/2020] [Indexed: 05/11/2023]
Affiliation(s)
- Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Frances C Sussmilch
- School of Natural Sciences, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Karen S Renzaglia
- Department of Plant Biology, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, Würzburg, D-97082, Germany
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Amelia Merced
- USDA Forest Service, International Institute of Tropical Forestry, San Juan, PR, 00926, USA
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Affiliation(s)
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London, UK.
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15
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Rimington WR, Duckett JG, Field KJ, Bidartondo MI, Pressel S. The distribution and evolution of fungal symbioses in ancient lineages of land plants. Mycorrhiza 2020; 30:23-49. [PMID: 32130512 PMCID: PMC7062687 DOI: 10.1007/s00572-020-00938-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/05/2020] [Indexed: 05/26/2023]
Abstract
An accurate understanding of the diversity and distribution of fungal symbioses in land plants is essential for mycorrhizal research. Here we update the seminal work of Wang and Qiu (Mycorrhiza 16:299-363, 2006) with a long-overdue focus on early-diverging land plant lineages, which were considerably under-represented in their survey, by examining the published literature to compile data on the status of fungal symbioses in liverworts, hornworts and lycophytes. Our survey combines data from 84 publications, including recent, post-2006, reports of Mucoromycotina associations in these lineages, to produce a list of at least 591 species with known fungal symbiosis status, 180 of which were included in Wang and Qiu (Mycorrhiza 16:299-363, 2006). Using this up-to-date compilation, we estimate that fewer than 30% of liverwort species engage in symbiosis with fungi belonging to all three mycorrhizal phyla, Mucoromycota, Basidiomycota and Ascomycota, with the last being the most widespread (17%). Fungal symbioses in hornworts (78%) and lycophytes (up to 100%) appear to be more common but involve only members of the two Mucoromycota subphyla Mucoromycotina and Glomeromycotina, with Glomeromycotina prevailing in both plant groups. Our fungal symbiosis occurrence estimates are considerably more conservative than those published previously, but they too may represent overestimates due to currently unavoidable assumptions.
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Affiliation(s)
- William R Rimington
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK
| | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK
| | - Silvia Pressel
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK.
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Rimington WR, Pressel S, Duckett JG, Field KJ, Bidartondo MI. Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts. Mycorrhiza 2019; 29:551-565. [PMID: 31720838 PMCID: PMC6890582 DOI: 10.1007/s00572-019-00918-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/13/2019] [Indexed: 05/09/2023]
Abstract
Like the majority of land plants, liverworts regularly form intimate symbioses with arbuscular mycorrhizal fungi (Glomeromycotina). Recent phylogenetic and physiological studies report that they also form intimate symbioses with Mucoromycotina fungi and that some of these, like those involving Glomeromycotina, represent nutritional mutualisms. To compare these symbioses, we carried out a global analysis of Mucoromycotina fungi in liverworts and other plants using species delimitation, ancestral reconstruction, and network analyses. We found that Mucoromycotina are more common and diverse symbionts of liverworts than previously thought, globally distributed, ancestral, and often co-occur with Glomeromycotina within plants. However, our results also suggest that the associations formed by Mucoromycotina fungi are fundamentally different because, unlike Glomeromycotina, they may have evolved multiple times and their symbiotic networks are un-nested (i.e., not forming nested subsets of species). We infer that the global Mucoromycotina symbiosis is evolutionarily and ecologically distinctive.
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Affiliation(s)
- William R Rimington
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK.
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK.
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK.
| | - Silvia Pressel
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Algae, Fungi and Plants Division, Natural History Museum, London, London, SW7 5BD, UK
| | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK.
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, TW9 3DS, UK.
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17
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Hoysted GA, Jacob AS, Kowal J, Giesemann P, Bidartondo MI, Duckett JG, Gebauer G, Rimington WR, Schornack S, Pressel S, Field KJ. Mucoromycotina Fine Root Endophyte Fungi Form Nutritional Mutualisms with Vascular Plants. Plant Physiol 2019; 181:565-577. [PMID: 31358684 PMCID: PMC6776871 DOI: 10.1104/pp.19.00729] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/22/2019] [Indexed: 05/23/2023]
Abstract
Fungi and plants have engaged in intimate symbioses that are globally widespread and have driven terrestrial biogeochemical processes since plant terrestrialization >500 million years ago. Recently, hitherto unknown nutritional mutualisms involving ancient lineages of fungi and nonvascular plants have been discovered, although their extent and functional significance in vascular plants remain uncertain. Here, we provide evidence of carbon-for-nitrogen exchange between an early-diverging vascular plant (Lycopodiella inundata) and Mucoromycotina (Endogonales) fine root endophyte fungi. Furthermore, we demonstrate that the same fungal symbionts colonize neighboring nonvascular and flowering plants. These findings fundamentally change our understanding of the physiology, interrelationships, and ecology of underground plant-fungal symbioses in modern terrestrial ecosystems by revealing the nutritional role of Mucoromycotina fungal symbionts in vascular plants.
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Affiliation(s)
- Grace A Hoysted
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alison S Jacob
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, United Kingdom
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Jill Kowal
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Philipp Giesemann
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95440 Bayreuth, Germany
| | - Martin I Bidartondo
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, United Kingdom
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Gerhard Gebauer
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95440 Bayreuth, Germany
| | - William R Rimington
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, United Kingdom
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Sebastian Schornack
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, United Kingdom
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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18
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Yu Y, Yang J, Ma W, Pressel S, Liu H, Wu Y, Schneider H. Chloroplast phylogenomics of liverworts: a reappraisal of the backbone phylogeny of liverworts with emphasis on Ptilidiales. Cladistics 2019; 36:184-193. [DOI: 10.1111/cla.12396] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2019] [Indexed: 01/20/2023] Open
Affiliation(s)
- Ying Yu
- College of Life and Environmental Sciences Hangzhou Normal University Hangzhou 311121 China
| | - Jun‐Bo Yang
- CAS Plant Germplasm and Genomics Center Germplasm Bank of Wild Species Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 China
| | - Wen‐Zhang Ma
- CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 China
| | - Silvia Pressel
- Department of Life Sciences Natural History Museum London SW7 5BD UK
| | - Hong‐Mei Liu
- Key Laboratory of Tropical Plant Resources and Sustainable Use Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun Yunnan 666303 China
| | - Yu‐Huan Wu
- College of Life and Environmental Sciences Hangzhou Normal University Hangzhou 311121 China
| | - Harald Schneider
- Center of Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun Yunnan 666303 China
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19
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Field KJ, Bidartondo MI, Rimington WR, Hoysted GA, Beerling D, Cameron DD, Duckett JG, Leake JR, Pressel S. Functional complementarity of ancient plant-fungal mutualisms: contrasting nitrogen, phosphorus and carbon exchanges between Mucoromycotina and Glomeromycotina fungal symbionts of liverworts. New Phytol 2019; 223:908-921. [PMID: 30919981 DOI: 10.1111/nph.15819] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/16/2019] [Indexed: 05/24/2023]
Abstract
Liverworts, which are amongst the earliest divergent plant lineages and important ecosystem pioneers, often form nutritional mutualisms with arbuscular mycorrhiza-forming Glomeromycotina and fine-root endophytic Mucoromycotina fungi, both of which coevolved with early land plants. Some liverworts, in common with many later divergent plants, harbour both fungal groups, suggesting these fungi may complementarily improve plant access to different soil nutrients. We tested this hypothesis by growing liverworts in single and dual fungal partnerships under a modern atmosphere and under 1500 ppm [CO2 ], as experienced by early land plants. Access to soil nutrients via fungal partners was investigated with 15 N-labelled algal necromass and 33 P orthophosphate. Photosynthate allocation to fungi was traced using 14 CO2 . Only Mucoromycotina fungal partners provided liverworts with substantial access to algal 15 N, irrespective of atmospheric CO2 concentration. Both symbionts increased 33 P uptake, but Glomeromycotina were often more effective. Dual partnerships showed complementarity of nutrient pool use and greatest photosynthate allocation to symbiotic fungi. We show there are important functional differences between the plant-fungal symbioses tested, providing new insights into the functional biology of Glomeromycotina and Mucoromycotina fungal groups that form symbioses with plants. This may explain the persistence of the two fungal lineages in symbioses across the evolution of land plants.
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Affiliation(s)
- Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS, UK
| | - William R Rimington
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS, UK
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Grace A Hoysted
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - DavidJ Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Jonathan R Leake
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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20
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Field KJ, Pressel S. Unity in diversity: structural and functional insights into the ancient partnerships between plants and fungi. New Phytol 2018; 220:996-1011. [PMID: 29696662 DOI: 10.1111/nph.15158] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/06/2018] [Indexed: 05/16/2023]
Abstract
Contents Summary 996 I. Introduction 996 II. An ancient, and diverse, symbiosis 998 III. Structural diversity in ancient plant-fungal partnerships 1000 IV. Mycorrhizal unity in host plant nutrition 1002 V. Plant-to-fungus carbon transfer 1003 VI. From individuals to networks 1003 VII. Diverse responses of mycorrhizal functioning to dynamic environments 1006 VIII. Summary of future research direction 1007 Acknowledgements 1006 References 1006 SUMMARY: Mycorrhizal symbiosis is an ancient and widespread mutualism between plants and fungi that facilitated plant terrestrialisation > 500 million years ago, with key roles in ecosystem functioning at multiple scales. Central to the symbiosis is the bidirectional exchange of plant-fixed carbon for fungal-acquired nutrients. Within this unifying role of mycorrhizas, considerable diversity in structure and function reflects the diversity of the partners involved. Early diverging plants form mutualisms not only with arbuscular mycorrhizal Glomeromycotina fungi, but also with poorly characterised Mucoromycotina, which may also colonise the roots of 'higher' plants as fine root endophytes. Functional diversity in these symbioses depends on both fungal and plant life histories and is influenced by the environment. Recent studies have highlighted the roles of lipids/fatty acids in plant-to-fungus carbon transport and potential contributions of Glomeromycotina fungi to plant nitrogen nutrition. Together with emerging appreciation of mycorrhizal networks as multi-species resource-sharing systems, these insights are broadening our views on mycorrhizas and their roles in nutrient cycling. It is crucial that the diverse array of biotic and abiotic factors that together shape the dynamics of carbon-for-nutrient exchange between plants and fungi are integrated, in addition to embracing the unfolding and potentially key role of Mucoromycotina fungi in these processes.
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Affiliation(s)
- Katie J Field
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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21
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Rimington WR, Pressel S, Duckett JG, Field KJ, Read DJ, Bidartondo MI. Ancient plants with ancient fungi: liverworts associate with early-diverging arbuscular mycorrhizal fungi. Proc Biol Sci 2018; 285:20181600. [PMID: 30305437 PMCID: PMC6191707 DOI: 10.1098/rspb.2018.1600] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/21/2018] [Indexed: 01/12/2023] Open
Abstract
Arbuscular mycorrhizas are widespread in land plants including liverworts, some of the closest living relatives of the first plants to colonize land 500 million years ago (MYA). Previous investigations reported near-exclusive colonization of liverworts by the most recently evolved arbuscular mycorrhizal fungi, the Glomeraceae, indicating a recent acquisition from flowering plants at odds with the widely held notion that arbuscular mycorrhizal-like associations in liverworts represent the ancestral symbiotic condition in land plants. We performed an analysis of symbiotic fungi in 674 globally collected liverworts using molecular phylogenetics and electron microscopy. Here, we show every order of arbuscular mycorrhizal fungi colonizes early-diverging liverworts, with non-Glomeraceae being at least 10 times more common than in flowering plants. Arbuscular mycorrhizal fungi in liverworts and other ancient plant lineages (hornworts, lycopods, and ferns) were delimited into 58 taxa and 36 singletons, of which at least 43 are novel and specific to liverworts. The discovery that early plant lineages are colonized by early-diverging fungi supports the hypothesis that arbuscular mycorrhizas are an ancestral symbiosis for all land plants.
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Affiliation(s)
- William R Rimington
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- Life Sciences Department, Algae, Fungi and Plants Division, Natural History Museum, London SW7 5BD, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UK
| | - Silvia Pressel
- Life Sciences Department, Algae, Fungi and Plants Division, Natural History Museum, London SW7 5BD, UK
| | - Jeffrey G Duckett
- Life Sciences Department, Algae, Fungi and Plants Division, Natural History Museum, London SW7 5BD, UK
| | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David J Read
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UK
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22
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Hoysted GA, Kowal J, Jacob A, Rimington WR, Duckett JG, Pressel S, Orchard S, Ryan MH, Field KJ, Bidartondo MI. A mycorrhizal revolution. Curr Opin Plant Biol 2018; 44:1-6. [PMID: 29289791 DOI: 10.1016/j.pbi.2017.12.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 05/27/2023]
Abstract
It has long been postulated that symbiotic fungi facilitated plant migrations onto land through enhancing the scavenging of mineral nutrients and exchanging these for photosynthetically fixed organic carbon. Today, land plant-fungal symbioses are both widespread and diverse. Recent discoveries show that a variety of potential fungal associates were likely available to the earliest land plants, and that these early partnerships were probably affected by changing atmospheric CO2 concentrations. Here, we evaluate current hypotheses and knowledge gaps regarding early plant-fungal partnerships in the context of newly discovered fungal mutualists of early and more recently evolved land plants and the rapidly changing views on the roles of plant-fungal symbioses in the evolution and ecology of the terrestrial biosphere.
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Affiliation(s)
- Grace A Hoysted
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Jill Kowal
- Department of Life Sciences, National History Museum, London SW7 5BD, UK
| | - Alison Jacob
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UK
| | - William R Rimington
- Department of Life Sciences, National History Museum, London SW7 5BD, UK; Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UK; Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, National History Museum, London SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, National History Museum, London SW7 5BD, UK
| | - Suzanne Orchard
- UWA School of Agriculture and Environment, and Institute of Agriculture, The University of Western Australia, 35 Stirling Hwy, Crawley (Perth), WA 6009, Australia
| | - Megan H Ryan
- UWA School of Agriculture and Environment, and Institute of Agriculture, The University of Western Australia, 35 Stirling Hwy, Crawley (Perth), WA 6009, Australia
| | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Martin I Bidartondo
- Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, UK; Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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Pressel S, Renzaglia KS, Dicky Clymo RS, Duckett JG. Hornwort stomata do not respond actively to exogenous and environmental cues. Ann Bot 2018; 122:45-57. [PMID: 29897395 PMCID: PMC6025193 DOI: 10.1093/aob/mcy045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/14/2018] [Indexed: 05/22/2023]
Abstract
Backgrounds and Aims Because stomata in bryophytes occur on sporangia, they are subject to different developmental and evolutionary constraints from those on leaves of tracheophytes. No conclusive experimental evidence exists on the responses of hornwort stomata to exogenous stimulation. Methods Responses of hornwort stomata to abscisic acid (ABA), desiccation, darkness and plasmolysis were compared with those in tracheophyte leaves. Potassium ion concentrations in the guard cells and adjacent cells were analysed by X-ray microanalysis, and the ontogeny of the sporophytic intercellular spaces was compared with those of tracheophytes by cryo-scanning electron microscopy. Key Results The apertures in hornwort stomata open early in development and thereafter remain open. In hornworts, the experimental treatments, based on measurements of >9000 stomata, produced only a slight reduction in aperture dimensions after desiccation and plasmolysis, and no changes following ABA treatments and darkness. In tracheophytes, all these treatments resulted in complete stomatal closure. Potassium concentrations are similar in hornwort guard cells and epidermal cells under all treatments at all times. The small changes in hornwort stomatal dimensions in response to desiccation and plasmolysis are probably mechanical and/or stress responses of all the epidermal and spongy chlorophyllose cells, affecting the guard cells. In contrast to their nascent gas-filled counterparts across tracheophytes, sporophytic intercellular spaces in hornworts are initially liquid filled. Conclusions Our experiments demonstrate a lack of physiological regulation of opening and closing of stomata in hornworts compared with tracheophytes, and support accumulating developmental and structural evidence that stomata in hornworts are primarily involved in sporophyte desiccation and spore discharge rather than the regulation of photosynthesis-related gaseous exchange. Our results run counter to the notion of the early acquisition of active control of stomatal movements in bryophytes as proposed from previous experiments on mosses.
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Affiliation(s)
- Silvia Pressel
- Life Sciences Department, Natural History Museum, London, UK
| | - Karen S Renzaglia
- Plant Biology Department, Southern Illinois University, Carbondale, USA
| | - Richard S Dicky Clymo
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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24
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Morris JL, Puttick MN, Clark JW, Edwards D, Kenrick P, Pressel S, Wellman CH, Yang Z, Schneider H, Donoghue PCJ. The timescale of early land plant evolution. Proc Natl Acad Sci U S A 2018; 115:E2274-E2283. [PMID: 29463716 PMCID: PMC5877938 DOI: 10.1073/pnas.1719588115] [Citation(s) in RCA: 400] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth's System. The sparseness of early land plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for Viridiplantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within Viridiplantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin.
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Affiliation(s)
- Jennifer L Morris
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Mark N Puttick
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
- Department of Earth Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - James W Clark
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10, United Kingdom
| | - Paul Kenrick
- Department of Earth Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Charles H Wellman
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Ziheng Yang
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
- Radclie Institute for Advanced Studies, Harvard University, Cambridge, MA 02138
| | - Harald Schneider
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom;
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- Center of Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan 666303, China
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom;
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Puttick MN, Morris JL, Williams TA, Cox CJ, Edwards D, Kenrick P, Pressel S, Wellman CH, Schneider H, Pisani D, Donoghue PCJ. The Interrelationships of Land Plants and the Nature of the Ancestral Embryophyte. Curr Biol 2018; 28:733-745.e2. [PMID: 29456145 DOI: 10.1016/j.cub.2018.01.063] [Citation(s) in RCA: 240] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 11/28/2022]
Abstract
The evolutionary emergence of land plant body plans transformed the planet. However, our understanding of this formative episode is mired in the uncertainty associated with the phylogenetic relationships among bryophytes (hornworts, liverworts, and mosses) and tracheophytes (vascular plants). Here we attempt to clarify this problem by analyzing a large transcriptomic dataset with models that allow for compositional heterogeneity between sites. Zygnematophyceae is resolved as sister to land plants, but we obtain several distinct relationships between bryophytes and tracheophytes. Concatenated sequence analyses that can explicitly accommodate site-specific compositional heterogeneity give more support for a mosses-liverworts clade, "Setaphyta," as the sister to all other land plants, and weak support for hornworts as the sister to all other land plants. Bryophyte monophyly is supported by gene concatenation analyses using models explicitly accommodating lineage-specific compositional heterogeneity and analyses of gene trees. Both maximum-likelihood analyses that compare the fit of each gene tree to proposed species trees and Bayesian supertree estimation based on gene trees support bryophyte monophyly. Of the 15 distinct rooted relationships for embryophytes, we reject all but three hypotheses, which differ only in the position of hornworts. Our results imply that the ancestral embryophyte was more complex than has been envisaged based on topologies recognizing liverworts as the sister lineage to all other embryophytes. This requires many phenotypic character losses and transformations in the liverwort lineage, diminishes inconsistency between phylogeny and the fossil record, and prompts re-evaluation of the phylogenetic affinity of early land plant fossils, the majority of which are considered stem tracheophytes.
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Affiliation(s)
- Mark N Puttick
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK; School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Jennifer L Morris
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK; School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Cymon J Cox
- Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-319 Faro, Portugal
| | - Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Paul Kenrick
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Charles H Wellman
- Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK
| | - Harald Schneider
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Center of Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan, China.
| | - Davide Pisani
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK.
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Kowal J, Pressel S, Duckett JG, Bidartondo MI, Field KJ. From rhizoids to roots? Experimental evidence of mutualism between liverworts and ascomycete fungi. Ann Bot 2018; 121:221-227. [PMID: 29300826 PMCID: PMC5808786 DOI: 10.1093/aob/mcx126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/19/2017] [Indexed: 05/03/2023]
Abstract
Background and Aims The rhizoids of leafy liverworts (Jungermanniales, Marchantiophyta) are commonly colonized by the ascomycete fungus Pezoloma ericae. These associations are hypothesized to be functionally analogous to the ericoid mycorrhizas (ErMs) formed by P. ericae with the roots of Ericaceae plants in terms of bi-directional phosphorus for carbon exchange; however, this remains unproven. Here, we test whether associations between the leafy liverwort Cephalozia bicuspidata and P. ericae are mutualistic. Methods We measured movement of phosphorus and carbon between C. bicuspidata and P. ericae using [33P]orthophosphate and 14CO2 isotope tracers in monoxenic cultures. We also measured leafy liverwort growth, with and without P. ericae. Key Results We present the first demonstration of nutritionally mutualistic symbiosis between a non-vascular plant and an ErM-forming fungus, showing transfer of fungal-acquired P to the liverwort and of liverwort-fixed C to the fungus alongside increased growth in fungus-colonized liverworts. Conclusions Thus, this ascomycete-liverwort symbiosis can now be described as mycorrhiza-like, providing further insights into ericoid mycorrhizal evolution and adding Ascomycota fungi to mycorrhizal fungal groups engaging in mutualisms with plants across the land plant phylogeny. As P. ericae also colonizes the rhizoids of Schistochilaceae liverworts, which originated in the Triassic and are sister to all other jungermannialean liverworts associated with fungi, our findings point toward an early origin of ascomycete-liverwort symbioses, possibly pre-dating their evolution in the Ericales by some 150 million years.
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Affiliation(s)
- Jill Kowal
- Imperial College London, London, UK
- Royal Botanic Gardens, Kew, Richmond, UK
- Natural History Museum, London, UK
| | | | | | | | - Katie J Field
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Duckett JG, Pressel S. The evolution of the stomatal apparatus: intercellular spaces and sporophyte water relations in bryophytes-two ignored dimensions. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160498. [PMID: 29254963 PMCID: PMC5745334 DOI: 10.1098/rstb.2016.0498] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2017] [Indexed: 11/12/2022] Open
Abstract
Cryo-scanning electron microscopy shows that nascent intercellular spaces (ICSs) in bryophytes are liquid-filled, whereas these are gas-filled from the outset in tracheophytes except in the gametophytes of Lycopodiales. ICSs are absent in moss gametophytes and remain liquid-filled in hornwort gametophytes and in both generations in liverworts. Liquid is replaced by gas following stomatal opening in hornworts and is ubiquitous in moss sporophytes even in astomate taxa. New data on moss water relations and sporophyte weights indicate that the latter are homiohydric while X-ray microanalysis reveals an absence of potassium pumps in the stomatal apparatus. The distribution of ICSs in bryophytes is strongly indicative of very ancient multiple origins. Inherent in this scenario is either the dual or triple evolution of stomata. The absence, in mosses, of any relationship between increases in sporophyte biomass and stomata numbers and absences, suggests that CO2 entry through the stomata, possible only after fluid replacement by gas in the ICSs, makes but a minor contribution to sporophyte nutrition. Save for a single claim of active regulation of aperture dimensions in mosses, all other functional and structural data point to the sporophyte desiccation, leading to spore discharge, as the primeval role of the stomatal apparatus.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Affiliation(s)
- Jeffrey G Duckett
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Field KJ, Rimington WR, Bidartondo MI, Allinson KE, Beerling DJ, Cameron DD, Duckett JG, Leake JR, Pressel S. Functional analysis of liverworts in dual symbiosis with Glomeromycota and Mucoromycotina fungi under a simulated Palaeozoic CO2 decline. ISME J 2016; 10:1514-26. [PMID: 26613340 PMCID: PMC5029179 DOI: 10.1038/ismej.2015.204] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 01/09/2023]
Abstract
Most land plants form mutualistic associations with arbuscular mycorrhizal fungi of the Glomeromycota, but recent studies have found that ancient plant lineages form mutualisms with Mucoromycotina fungi. Simultaneous associations with both fungal lineages have now been found in some plants, necessitating studies to understand the functional and evolutionary significance of these tripartite associations for the first time. We investigate the physiology and cytology of dual fungal symbioses in the early-diverging liverworts Allisonia and Neohodgsonia at modern and Palaeozoic-like elevated atmospheric CO2 concentrations under which they are thought to have evolved. We found enhanced carbon cost to liverworts with simultaneous Mucoromycotina and Glomeromycota associations, greater nutrient gain compared with those symbiotic with only one fungal group in previous experiments and contrasting responses to atmospheric CO2 among liverwort-fungal symbioses. In liverwort-Mucoromycotina symbioses, there is increased P-for-C and N-for-C exchange efficiency at 440 p.p.m. compared with 1500 p.p.m. CO2. In liverwort-Glomeromycota symbioses, P-for-C exchange is lower at ambient CO2 compared with elevated CO2. No characteristic cytologies of dual symbiosis were identified. We provide evidence of a distinct physiological niche for plant symbioses with Mucoromycotina fungi, giving novel insight into why dual symbioses with Mucoromycotina and Glomeromycota fungi persist to the present day.
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Affiliation(s)
- Katie J Field
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - William R Rimington
- Department of Life Sciences, Imperial College London, London, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, UK
- Department of Life Sciences, Natural History Museum, London, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, UK
| | - Kate E Allinson
- Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK
| | - David J Beerling
- Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK
| | | | - Jonathan R Leake
- Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History Museum, London, UK
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Kowal J, Pressel S, Duckett JG, Bidartondo MI. Liverworts to the rescue: an investigation of their efficacy as mycorrhizal inoculum for vascular plants. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12580] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Jill Kowal
- Imperial College London South Kensington Campus London SW7 2AZ UK
- Royal Botanic Gardens, Kew Jodrell Laboratory Richmond Kew TW9 3AB UK
| | | | | | - Martin I. Bidartondo
- Imperial College London South Kensington Campus London SW7 2AZ UK
- Royal Botanic Gardens, Kew Jodrell Laboratory Richmond Kew TW9 3AB UK
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Field KJ, Duckett JG, Cameron DD, Pressel S. Stomatal density and aperture in non-vascular land plants are non-responsive to above-ambient atmospheric CO2 concentrations. Ann Bot 2015; 115:915-22. [PMID: 25858324 PMCID: PMC4407062 DOI: 10.1093/aob/mcv021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/07/2015] [Accepted: 01/26/2015] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS Following the consensus view for unitary origin and conserved function of stomata across over 400 million years of land plant evolution, stomatal abundance has been widely used to reconstruct palaeo-atmospheric environments. However, the responsiveness of stomata in mosses and hornworts, the most basal stomate lineages of extant land plants, has received relatively little attention. This study aimed to redress this imbalance and provide the first direct evidence of bryophyte stomatal responsiveness to atmospheric CO2. METHODS A selection of hornwort (Anthoceros punctatus, Phaeoceros laevis) and moss (Polytrichum juniperinum, Mnium hornum, Funaria hygrometrica) sporophytes with contrasting stomatal morphologies were grown under different atmospheric CO2 concentrations ([CO2]) representing both modern (440 p.p.m. CO2) and ancient (1500 p.p.m. CO2) atmospheres. Upon sporophyte maturation, stomata from each bryophyte species were imaged, measured and quantified. KEY RESULTS Densities and dimensions were unaffected by changes in [CO2], other than a slight increase in stomatal density in Funaria and abnormalities in Polytrichum stomata under elevated [CO2]. CONCLUSIONS The changes to stomata in Funaria and Polytrichum are attributed to differential growth of the sporophytes rather than stomata-specific responses. The absence of responses to changes in [CO2] in bryophytes is in line with findings previously reported in other early lineages of vascular plants. These findings strengthen the hypothesis of an incremental acquisition of stomatal regulatory processes through land plant evolution and urge considerable caution in using stomatal densities as proxies for paleo-atmospheric CO2 concentrations.
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Affiliation(s)
- Katie J Field
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Jeffrey G Duckett
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Silvia Pressel
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Affiliation(s)
- William R Rimington
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS, UK
- Department of Life Sciences, Plants Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Silvia Pressel
- Department of Life Sciences, Plants Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Plants Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS, UK
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Field KJ, Rimington WR, Bidartondo MI, Allinson KE, Beerling DJ, Cameron DD, Duckett JG, Leake JR, Pressel S. First evidence of mutualism between ancient plant lineages (Haplomitriopsida liverworts) and Mucoromycotina fungi and its response to simulated Palaeozoic changes in atmospheric CO2. New Phytol 2015; 205:743-56. [PMID: 25230098 PMCID: PMC4303992 DOI: 10.1111/nph.13024] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/06/2014] [Indexed: 05/20/2023]
Abstract
The discovery that Mucoromycotina, an ancient and partially saprotrophic fungal lineage, associates with the basal liverwort lineage Haplomitriopsida casts doubt on the widely held view that Glomeromycota formed the sole ancestral plant-fungus symbiosis. Whether this association is mutualistic, and how its functioning was affected by the fall in atmospheric CO2 concentration that followed plant terrestrialization in the Palaeozoic, remains unknown. We measured carbon-for-nutrient exchanges between Haplomitriopsida liverworts and Mucoromycotina fungi under simulated mid-Palaeozoic (1500 ppm) and near-contemporary (440 ppm) CO2 concentrations using isotope tracers, and analysed cytological differences in plant-fungal interactions. Concomitantly, we cultured both partners axenically, resynthesized the associations in vitro, and characterized their cytology. We demonstrate that liverwort-Mucoromycotina symbiosis is mutualistic and mycorrhiza-like, but differs from liverwort-Glomeromycota symbiosis in maintaining functional efficiency of carbon-for-nutrient exchange between partners across CO2 concentrations. Inoculation of axenic plants with Mucoromycotina caused major cytological changes affecting the anatomy of plant tissues, similar to that observed in wild-collected plants colonized by Mucoromycotina fungi. By demonstrating reciprocal exchange of carbon for nutrients between partners, our results provide support for Mucoromycotina establishing the earliest mutualistic symbiosis with land plants. As symbiotic functional efficiency was not compromised by reduced CO2 , we suggest that other factors led to the modern predominance of the Glomeromycota symbiosis.
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Affiliation(s)
- Katie J Field
- Department of Animal and Plant Sciences, Western Bank, University of SheffieldSheffield, S10 2TN, UK
| | - William R Rimington
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic GardensKew, TW9 3DS, UK
- Department of Life Sciences, Natural History MuseumCromwell Road, London, SW7 5BD, UK
| | - Martin I Bidartondo
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
- Jodrell Laboratory, Royal Botanic GardensKew, TW9 3DS, UK
| | - Kate E Allinson
- Department of Animal and Plant Sciences, Western Bank, University of SheffieldSheffield, S10 2TN, UK
| | - David J Beerling
- Department of Animal and Plant Sciences, Western Bank, University of SheffieldSheffield, S10 2TN, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, Western Bank, University of SheffieldSheffield, S10 2TN, UK
| | - Jeffrey G Duckett
- Department of Life Sciences, Natural History MuseumCromwell Road, London, SW7 5BD, UK
| | - Jonathan R Leake
- Department of Animal and Plant Sciences, Western Bank, University of SheffieldSheffield, S10 2TN, UK
| | - Silvia Pressel
- Department of Life Sciences, Natural History MuseumCromwell Road, London, SW7 5BD, UK
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Strullu-Derrien C, Kenrick P, Pressel S, Duckett JG, Rioult JP, Strullu DG. Fungal associations in Horneophyton ligneri from the Rhynie Chert (c. 407 million year old) closely resemble those in extant lower land plants: novel insights into ancestral plant-fungus symbioses. New Phytol 2014; 203:964-79. [PMID: 24750009 DOI: 10.1111/nph.12805] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/04/2014] [Indexed: 05/13/2023]
Abstract
Fungi (Eumycota) form close associations with plants, with which they have co-existed since the dawn of life on land, but their diversity in early terrestrial ecosystems is still poorly understood. We studied petrographic sections of exceptionally well-preserved petrified plants from the 407 million yr-old Rhynie Chert (Scotland, UK). For comparative purposes, we illustrate fungal associations in four extant lower land plants. We document two new endophytes in the plant Horneophyton lignieri: Palaeoglomus boullardii (sp. nov. Glomeromycota) colonizes parenchyma in a discontinuous zone of the outer cortex of the aerial axes, forming arbuscule-like structures, vesicles and spores; Palaeoendogone gwynne-vaughaniae (gen. nov., sp. nov. Mucoromycotina) colonizes parenchyma in the basal part of the plant, where it is present in intercellular spaces and as intracellular coils but absent from rhizoids. Critical comparisons between the newly discovered Horneophyton endophytes, fungi previously described from the Rhynie Chert and fungal colonization in extant lower land plants reveal several features characteristic of both Mucoromycotina and Glomeromycota. A reappraisal of fungal associations in early land plants indicates that they are more diverse than assumed hitherto, overturning the long-held paradigm that the early endophytes were exclusively Glomeromycota.
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Affiliation(s)
- Christine Strullu-Derrien
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK; Laboratoire Mycorhizes, Faculté des Sciences, Université d'Angers, 49045, Angers Cedex, France
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Barclay RS, McElwain JC, Duckett JG, van Es MH, Mostaert AS, Pressel S, Sageman BB. New methods reveal oldest known fossil epiphyllous moss: Bryiidites utahensis gen. et sp. nov. (Bryidae). Am J Bot 2013; 100:2450-2457. [PMID: 24302691 DOI: 10.3732/ajb.1300209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY Epiphyllous bryophytes are a highly characteristic feature of many humid tropical forest ecosystems. In contrast to the extensive fossil record for the leaves of their host plants, the record is virtually nonexistent for the epiphylls themselves, despite a fossil record for mosses that begins in the Middle Carboniferous Period, 330 million years ago. METHODS Epifluorescence optical microscopy, scanning electron microscopy, and atomic force microscopy were employed to investigate an intimate association between a newly discovered epiphyllous moss and a Lauraceae plant host from the middle Cretaceous. KEY RESULTS We describe the oldest fossil specimen of an epiphyllous moss, Bryiidites utahensis gen. et sp. nov., identified from an individual specimen only 450 µm long, situated on an approximately one millimeter square fossil leaf fragment. The moss epiphyll is exquisitely preserved as germinating spores and short-celled protonemata with transverse and oblique cross-walls closely matching those of extant epiphyllous mosses on the surface of the plant-leaf hosts. CONCLUSIONS The extension of the epiphyll record back to the middle Cretaceous provides fossil evidence for the appearance of epiphyllous mosses during the diversification of flowering plants, at least 95 million years ago. It also provides substantive evidence for a tropical maritime climate in central North America during the middle Cretaceous.
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Affiliation(s)
- Richard S Barclay
- Northwestern University, Department of Earth & Planetary Sciences, Technological Institute, 2145 Sheridan Road, Evanston, Illinois 60208-3130 USA
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Abstract
Hornworts are considered the sister group to vascular plants, but their fungal associations remain largely unexplored. The ancestral symbiotic condition for all plants is, nonetheless, widely assumed to be arbuscular mycorrhizal with Glomeromycota fungi. Owing to a recent report of other fungi in some non-vascular plants, here we investigate the fungi associated with diverse hornworts worldwide, using electron microscopy and molecular phylogenetics. We found that both Glomeromycota and Mucoromycotina fungi can form symbioses with most hornworts, often simultaneously. This discovery indicates that ancient terrestrial plants relied on a wider and more versatile symbiotic repertoire than previously thought, and it highlights the so far unappreciated ecological and evolutionary role of Mucoromycotina fungi.
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Affiliation(s)
- Alessandro Desirò
- Department of Life Sciences and Systems Biology, University of Turin, Viale P.A. Mattioli 25, 10125, Turin, Italy.
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Abstract
*Set out here is the first generic account of the cytological effects of dehydration and rehydration and exogenous abscisic acid on moss protonemata. *Protonemal cells were subjected to slow and fast drying regimes, with and without prior exposure to abscisic acid. The cytological changes associated with de- and rehydration were analysed by light, fluorescence and transmission electron microscopy, together with pharmacological studies. *Protonemata survive slow but not fast drying, unless pretreated with abscisic acid. Dehydration elicits profound cytological changes, namely vacuolar fragmentation, reorganization of the endomembrane domains, changes in the thickness of the cell wall and in the morphology of plastids and mitochondria, and the controlled dismantling of the cytoskeleton; these dynamic events are prevented by fast drying. In control cells, abscisic acid elicits changes that partially mimic those associated with slow drying, including controlled disassembly of cytoskeletal elements, thus enabling protonemal cells to survive normally lethal rates of water loss. *Our demonstration that moss protonemata are an ideal system for visualizing and manipulating the cytological events associated with vegetative desiccation tolerance in land plants now opens up the way for genomic dissection of the underlying mechanisms.
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Affiliation(s)
- Silvia Pressel
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK.
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Duckett JG, Pressel S, P'ng KMY, Renzaglia KS. Exploding a myth: the capsule dehiscence mechanism and the function of pseudostomata in Sphagnum. New Phytol 2009; 183:1053-1063. [PMID: 19552695 DOI: 10.1111/j.1469-8137.2009.02905.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The nineteenth century air-gun explanation for explosive spore discharge in Sphagnum has never been tested experimentally. Similarly, the function of the numerous stomata ubiquitous in the capsule walls has never been investigated. Both intact and pricked Sphagnum capsules, that were allowed to dry out, all dehisced over an 8-12 h period during which time the stomatal guard cells gradually collapsed and their potassium content, measured by X-ray microanalysis in a cryoscanning electron microscope, gradually increased. By contrast, guard cell potassium fell in water-stressed Arabidopsis. The pricking experiments demonstrate that the air-gun notion for explosive spore discharge in Sphagnum is inaccurate; differential shrinkage of the capsule walls causes popping off the rigid operculum. The absence of evidence for a potassium-regulating mechanism in the stomatal guard cells and their gradual collapse before spore discharge indicates that their sole role is facilitation of sporophyte desiccation that ultimately leads to capsule dehiscence. Our novel functional data on Sphagnum, when considered in relation to bryophyte phylogeny, suggest the possibility that stomata first appeared in land plants as structures that facilitated sporophyte drying out before spore discharge and only subsequently acquired their role in the regulation of gaseous exchange.
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Affiliation(s)
- Jeffrey G Duckett
- School of Biological and Chemical Sciences, Queen Mary University of London E1 4NS, UK
| | - Silvia Pressel
- School of Biological and Chemical Sciences, Queen Mary University of London E1 4NS, UK
| | - Ken M Y P'ng
- Department of Materials, Queen Mary University of London E1 4NS, UK
| | - Karen S Renzaglia
- Plant Biology Department, Southern Illinois University, Carbondale, IL 62901, USA
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Pressel S, Ligrone R, Duckett JG. Cellular differentiation in moss protonemata: a morphological and experimental study. Ann Bot 2008; 102:227-45. [PMID: 18508779 PMCID: PMC2712367 DOI: 10.1093/aob/mcn080] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 03/11/2008] [Accepted: 04/23/2008] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND AIMS Previous studies of protonemal morphogenesis in mosses have focused on the cytoskeletal basis of tip growth and the production of asexual propagules. This study provides the first comprehensive description of the differentiation of caulonemata and rhizoids, which share the same cytology, and the roles of the cytoskeleton in organelle shaping and spatial arrangement. METHODS Light and electron microscope observations were carried out on in vitro cultured and wild protonemata from over 200 moss species. Oryzalin and cytochalasin D were used to investigate the role of the cytoskeleton in the cytological organization of fully differentiated protonemal cells; time-lapse photography was employed to monitor organelle positions. KEY RESULTS The onset of differentiation in initially highly vacuolate subapical cells is marked by the appearance of tubular endoplasmic reticulum (ER) profiles with crystalline inclusions, closely followed by an increase in rough endoplasmic reticulum (RER). The tonoplast disintegrates and the original vacuole is replaced by a population of vesicles and small vacuoles originating de novo from RER. The cytoplasm then becomes distributed throughout the cell lumen, an event closely followed by the appearance of endoplasmic microtubules (MTs) in association with sheets of ER, stacks of vesicles that subsequently disperse, elongate mitochondria and chloroplasts and long tubular extensions at both poles of the nucleus. The production of large vesicles by previously inactive dictysomes coincides with the deposition of additional cell wall layers. At maturity, the numbers of endoplasmic microtubules decline, dictyosomes become inactive and the ER is predominantly smooth. Fully developed cells remain largely unaffected by cytochalasin; oryzalin elicits profound cytological changes. Both inhibitors elicit the formation of giant plastids. The plastids and other organelles in fully developed cells are largely stationary. CONCLUSIONS Differentiation of caulonemata and rhizoids involves a remarkable series of cytological changes, some of which closely recall major events in sieve element ontogeny in tracheophytes. The cytology of fully differentiated cells is remarkably similar to that of moss food-conducting cells and, in both, is dependent on an intact microtubule cytoskeleton. The disappearance of the major vacuolar apparatus is probably related to the function of caulonema and rhizoids in solute transport. Failure of fully differentiated caulonema and rhizoid cells to regenerate is attributed to a combination of endo-reduplication and irreversible tonoplast fragmentation. The formation of giant plastids, most likely by fusion, following both oryzalin and cytochalasin treatments, suggests key roles for both microtubules and microfilaments in the spatial arrangement and replication of plastids.
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Affiliation(s)
- Silvia Pressel
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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Pressel S, Ligrone R, Duckett JG, Davis EC. A novel ascomycetous endophytic association in the rhizoids of the leafy liverwort family, Schistochilaceae (Jungermanniidae, Hepaticopsida). Am J Bot 2008; 95:531-541. [PMID: 21632379 DOI: 10.3732/ajb.2007171] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Liverworts form diverse associations with endophytic fungi similar to mycorrhizas in vascular plants. Whereas the widespread occurrence of glomeromycotes in the basal liverwort lineages is well documented, knowledge of the distribution of ascomycetes and basidiomycetes in derived thalloid and leafy clades is more fragmented. Our discovery that the ramified and septate rhizoids of the Schistochilaceae, the sister group to all other ascomycete-containing liverworts, are packed with fungal hyphae prompted this study on the effects of the fungi on rhizoid morphology, host specificity, the cytology of the association, and a molecular analysis of the endophytes. Two species of Pachyschistochila and their fungi were grown axenically. Axenic rhizoids were unbranched and nonseptate. Reinfected with their own fungus and that from the other species, both Pachyschistochila species produced branched and septate rhizoids identical to those in nature. Woronin bodies and simple septa identified the fungus as an ascomycete referable, according to phylogenetic analyses of ITS sequences, to the Rhizoscyphus (Hymenoscyphus) ericae aggregate, also found in other liverwort-ascomycete associations and in mycorrhizas in the Ericales. Healthy hyphae and host cytoplasm suggest that the Schistochila-fungus association reflects a balanced mutualistic relationship. The recent dating of the divergence of the Jungermanniales from the fungus-free Porellales in the Permian and the origins of the Schistochilaceae in the Triassic indicate that these associations in liverworts predate the appearance of the Ericales.
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Affiliation(s)
- Silvia Pressel
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Pressel S, Ligrone R, Duckett JG. Chapter Six: The Ascomycete Rhizoscyphus ericae Elicits a Range of Host Responses in the Rhizoids of Leafy Liverworts: An Experimental and Cytological Analysis. ACTA ACUST UNITED AC 2008. [DOI: 10.3158/0015-0746-47.1.59] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Danesh J, Erqou S, Walker M, Thompson SG, Tipping R, Ford C, Pressel S, Walldius G, Jungner I, Folsom AR, Chambless LE, Knuiman M, Whincup PH, Wannamethee SG, Morris RW, Willeit J, Kiechl S, Santer P, Mayr A, Wald N, Ebrahim S, Lawlor DA, Yarnell JWG, Gallacher J, Casiglia E, Tikhonoff V, Nietert PJ, Sutherland SE, Bachman DL, Keil JE, Cushman M, Psaty BM, Tracy RP, Tybjaerg-Hansen A, Nordestgaard BG, Frikke-Schmidt R, Giampaoli S, Palmieri L, Panico S, Vanuzzo D, Pilotto L, Simons L, McCallum J, Friedlander Y, Fowkes FGR, Lee AJ, Smith FB, Taylor J, Guralnik J, Phillips C, Wallace R, Blazer D, Khaw KT, Jansson JH, Donfrancesco C, Salomaa V, Harald K, Jousilahti P, Vartiainen E, Woodward M, D'Agostino RB, Wolf PA, Vasan RS, Pencina MJ, Bladbjerg EM, Jorgensen T, Moller L, Jespersen J, Dankner R, Chetrit A, Lubin F, Rosengren A, Wilhelmsen L, Lappas G, Eriksson H, Bjorkelund C, Cremer P, Nagel D, Tilvis R, Strandberg T, Rodriguez B, Bouter LM, Heine RJ, Dekker JM, Nijpels G, Stehouwer CDA, Rimm E, Pai J, Sato S, Iso H, Kitamura A, Noda H, Goldbourt U, Salomaa V, Salonen JT, Nyyssönen K, Tuomainen TP, Deeg D, Poppelaars JL, Meade T, Cooper J, Hedblad B, Berglund G, Engstrom G, Döring A, Koenig W, Meisinger C, Mraz W, Kuller L, Selmer R, Tverdal A, Nystad W, Gillum R, Mussolino M, Hankinson S, Manson J, De Stavola B, Knottenbelt C, Cooper JA, Bauer KA, Rosenberg RD, Sato S, Naito Y, Holme I, Nakagawa H, Miura H, Ducimetiere P, Jouven X, Crespo C, Garcia-Palmieri M, Amouyel P, Arveiler D, Evans A, Ferrieres J, Schulte H, Assmann G, Shepherd J, Packard C, Sattar N, Cantin B, Lamarche B, Després JP, Dagenais GR, Barrett-Connor E, Wingard D, Bettencourt R, Gudnason V, Aspelund T, Sigurdsson G, Thorsson B, Trevisan M, Witteman J, Kardys I, Breteler M, Hofman A, Tunstall-Pedoe H, Tavendale R, Lowe GDO, Ben-Shlomo Y, Howard BV, Zhang Y, Best L, Umans J, Onat A, Meade TW, Njolstad I, Mathiesen E, Lochen ML, Wilsgaard T, Gaziano JM, Stampfer M, Ridker P, Ulmer H, Diem G, Concin H, Rodeghiero F, Tosetto A, Brunner E, Shipley M, Buring J, Cobbe SM, Ford I, Robertson M, He Y, Ibanez AM, Feskens EJM, Kromhout D, Collins R, Di Angelantonio E, Kaptoge S, Lewington S, Orfei L, Pennells L, Perry P, Ray K, Sarwar N, Scherman M, Thompson A, Watson S, Wensley F, White IR, Wood AM. The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases. Eur J Epidemiol 2007; 22:839-69. [PMID: 17876711 DOI: 10.1007/s10654-007-9165-7] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 07/02/2007] [Indexed: 01/22/2023]
Abstract
Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.
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Rowntree JK, Duckett JG, Mortimer CL, Ramsay MM, Pressel S. Formation of specialized propagules resistant to desiccation and cryopreservation in the threatened moss Ditrichum plumbicola (Ditrichales, Bryopsida). Ann Bot 2007; 100:483-96. [PMID: 17666410 PMCID: PMC2533608 DOI: 10.1093/aob/mcm141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 05/25/2007] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Successful cryopreservation of bryophytes is linked to intrinsic desiccation tolerance and survival can be enhanced by pre-treatment with abscisic acid (ABA) and sucrose. The pioneer moss Ditrichum plumbicola is naturally subjected to desiccation in the field but showed unexpectedly low survival of cryopreservation, as well as a poor response to pre-treatment. The effects of the cryopreservation protocol on protonemata of D. plumbicola were investigated in order to explore possible relationships between the production in vitro of cryopreservation-tolerant asexual propagules and the reproductive biology of D. plumbicola in nature. METHODS Protonemata were prepared for cryopreservation using a four-step protocol involving encapsulation in sodium alginate, pre-treatment for 2 weeks with ABA and sucrose, desiccation for 6 h and rapid freezing in liquid nitrogen. After each stage, protonemata were prepared for light and electron microscopy and growth on standard medium was monitored. Further samples were prepared for light and electron microscopy at intervals over a 24-h period following removal from liquid nitrogen and re-hydration. KEY RESULTS Pre-treatment with ABA and sucrose caused dramatic changes to the protonemata. Growth was arrested and propagules induced with pronounced morphological and cytological changes. Most cells died, but those that survived were characterized by thick, deeply pigmented walls, numerous small vacuoles and lipid droplets in their cytoplasm. Desiccation and cryopreservation elicited no dramatic cytological changes. Cells returned to their pre-dehydration and cryopreservation state within 2 h of re-hydration and/or removal from liquid nitrogen. Regeneration was normal once the ABA/sucrose stimulus was removed. CONCLUSIONS The ABA/sucrose pre-treatment induced the formation of highly desiccation- and cryopreservation-tolerant propagules from the protonemata of D. plumbicola. This parallels behaviour in the wild, where highly desiccation-tolerant rhizoids function as perennating organs allowing the moss to endure extreme environmental conditions. An involvement of endogenous ABA in the desiccation tolerance of D. plumbicola is suggested.
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Affiliation(s)
- J K Rowntree
- Micropropagation Unit, Royal Botanic Gardens Kew, Richmond, Surrey TW9 3AB, UK.
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Pressel S, Ligrone R, Duckett JG. Effects of de- and rehydration on food-conducting cells in the moss Polytrichum formosum: a cytological study. Ann Bot 2006; 98:67-76. [PMID: 16735407 PMCID: PMC2803544 DOI: 10.1093/aob/mcl092] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 12/16/2005] [Accepted: 03/21/2006] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS Moss food-conducting cells (leptoids and specialized parenchyma cells) have a highly distinctive cytology characterized by a polarized cytoplasmic organization and longitudinal alignment of plastids, mitochondria, endoplasmic reticulum and vesicles along endoplasmic microtubules. Previous studies on the desiccation biology of mosses have focused almost exclusively on photosynthetic tissues; the effects of desiccation on food-conducting cells are unknown. Reported here is a cytological study of the effects of de- and rehydration on food-conducting cells in the desiccation-tolerant moss Polytrichum formosum aimed at exploring whether the remarkable subcellular organization of these cells is related to the ability of mosses to survive desiccation. METHODS Shoots of Polytrichum formosum were dehydrated under natural conditions and prepared for transmission and scanning electron microscopy using both standard and anhydrous chemical fixation protocols. Replicate samples were then fixed at intervals over a 24-h period following rehydration in either water or in a 10 microM solution of the microtubule-disrupting drug oryzalin. KEY RESULTS Desiccation causes dramatic changes; the endoplasmic microtubules disappear; the nucleus, mitochondria and plastids become rounded and the longitudinal alignment of the organelles is lost, though cytoplasmic polarity is in part retained. Prominent stacks of endoplasmic reticulum, typical of the hydrated condition, are replaced with membranous tubules arranged at right angles to the main cellular axis. The internal cytoplasm becomes filled with small vacuoles and the plasmalemma forms labyrinthine tubular extensions outlining newly deposited ingrowths of cell wall material. Whereas plasmodesmata in meristematic cells at the shoot apex and in stem parenchyma cells appear to be unaffected by dehydration, those in leptoids become plugged with electron-opaque material. Starch deposits in parenchyma cells adjoining leptoids are depleted in desiccated plants. Rehydration sees complete reestablishment over a 12- to 24-h period of the cytology seen in the control plants. Oryzalin effectively prevents leptoid recovery. CONCLUSIONS The results point to a key role of the microtubular cytoskeleton in the rapid re-establishment of the elaborate cytoplasmic architecture of leptoids during rehydration. The reassembly of the endoplasmic microtubule system appears to dictate the time frame for the recovery process. The failure of leptoids to recover normal cytology in the presence of oryzalin further underlines the key role of the microtubules in the control of leptoid cytological organization.
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Affiliation(s)
- Silvia Pressel
- School of Biological Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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Pressel S, Duckett JG. The parasitic ascomycete Mniaecia jungermanniae induces the formation of giant perichaetia and apogamous sporophytes in leafy liverworts. ACTA ACUST UNITED AC 2006. [DOI: 10.1139/b06-004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the hypothesis that the apothecia of Mniaecia jungermanniae (Nees ex Fr.) Boud. growing on stems of the liverwort Cephalozia bicuspidata (L.) Dumort. might be the perfect stage of an ascomycete fungus forming a symbiotic association with swollen rhizoids in a liverwort, we grew both axenically and resynthesized the association. Contrary to our expectation, Mniaecia remained extracellular, but induced, on Cephalozia , the formation of giant perichaetia containing supernumerary archegonia followed by parthenogenetic and apogamous sporophytes. This is the first report of these latter two features in liverworts. By analogy with apogamy and apospory in mosses and pteridophytes that are induced by media supplemented with organic nutrients and growth regulators, we suggest that the abnormal structures in Cephalozia resulted from substances produced by Mniaecia. Giant perichaetia and abnormal perianths were also observed on wild colonies of Cephalozia, Diplophyllum , and Scapania heavily infected with Mniaecia. Apart from local depression of perianth formation in the wild, this parasitic fungus appears to cause no long-term damage to its hosts.
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Affiliation(s)
- Silvia Pressel
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Jeffrey G Duckett
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
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Wright JT, Cushman WC, Davis BR, Barzilay J, Colon P, Egan D, Lucente T, Nwachuku C, Pressel S, Leenen FH, Frolkis J, Letterer R, Walsh S, Tobin JN, Deger GE. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT): clinical center recruitment experience. Control Clin Trials 2001; 22:659-73. [PMID: 11738122 DOI: 10.1016/s0197-2456(01)00176-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a randomized clinical outcome trial of antihypertensive and lipid-lowering therapy in a diverse population (including substantial numbers of women and minorities) of 42,419 high-risk hypertensives aged > or = 55 years with a planned mean follow-up of 6 years. In this paper, we describe our experience in the identification, recruitment, and selection of clinical centers for this large simple trial capable of meeting the recruitment goals outlined for ALLHAT, and we highlight factors associated with clinical center performance. Over 135,000 recruitment brochures were mailed to physicians. Requests for information and application packets were received from 9351 (6.8%) interested investigators. A total of 1053 completed applications were received and 909 sites (86%) were eventually approved to join the trial. Of the approved sites, 278 either later declined participation or were never activated, and 8 were closed within a year for lack of enrollment. The final 623 randomizing centers exceeded the trial's recruitment goal to enroll at least 40,000 participants into the trial, although the recruitment period was extended 1.5 years longer than planned. Fewer than a quarter of the sites (22.6%) were recruited from academic medical centers or Department of Veterans Affairs Medical Centers. More than half of the sites (54.7%) were private solo or group practices, which contributed 53% of randomized participants. Community health centers comprised about 8% of the ALLHAT sites and 2.9% were part of health maintenance organizations. More than 22% of the principal investigators reported that they had no previous clinical research experience. In summary, ALLHAT was successful in recruiting a diverse group of clinical centers to achieve its patient recruitment goals.
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Affiliation(s)
- J T Wright
- Clinical Hypertension Program, Division of Hypertension, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4982, USA.
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Pressel S, Davis BR, Louis GT, Whelton P, Adrogue H, Egan D, Farber M, Payne G, Probstfield J, Ward H. Participant recruitment in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). Control Clin Trials 2001; 22:674-86. [PMID: 11738123 DOI: 10.1016/s0197-2456(01)00177-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a practice-based, randomized, multicenter clinical trial in 42,419 high-risk hypertensive patients aged 55 years and older; 10,356 of these patients are also in a lipid-lowering trial component. The purpose of the antihypertensive component is to determine whether the occurrence of fatal coronary heart disease and/or nonfatal myocardial infarction differs between patients randomized to diuretic (chlorthalidone) and those randomized to either calcium antagonist (amlodipine), angiotensin-converting enzyme inhibitor (lisinopril), or alpha-adrenergic blocker (doxazosin) therapy. (The doxazosin arm has been discontinued.) The purpose of the lipid-lowering component is to determine whether lowering low-density lipoprotein cholesterol with a 3-hydroxymethyl-glutaryl coenzyme A reductase inhibitor (pravastatin) in moderately hypercholesterolemic patients will reduce all-cause mortality compared to a control group receiving "usual care." ALLHAT recruited patients from a variety of practice settings from February 1994 through January 1998. Sites were paid for randomizations and are paid for completed follow-up visits and documented study events. Communication and monitoring were facilitated by nine regional coordinator teams. It was recognized from the outset that patient recruitment would be a very large task because of the number of participants (> 40,000) needed, the ambitious nature of the goal for recruitment of African-Americans (> 55%), and the knowledge that many investigators had limited experience recruiting participants for clinical trials. Multiple adjustments in the initial ALLHAT overall recruitment plan facilitated achievement of sample size goals for both components of the trial. The experience obtained from this large trial should be valuable for the planning and implementation of successful recruitment in future trials.
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Affiliation(s)
- S Pressel
- The University of Texas Health Science Center School of Public Health, 1200 Herman Pressler St., Suite E801, Houston, TX 77030, USA.
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Perry HM, Davis BR, Price TR, Applegate WB, Fields WS, Guralnik JM, Kuller L, Pressel S, Stamler J, Probstfield JL. Effect of treating isolated systolic hypertension on the risk of developing various types and subtypes of stroke: the Systolic Hypertension in the Elderly Program (SHEP). JAMA 2000; 284:465-71. [PMID: 10904510 DOI: 10.1001/jama.284.4.465] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT The Systolic Hypertension in the Elderly Program (SHEP) demonstrated that treating isolated systolic hypertension in older patients decreased incidence of total stroke, but whether all types of stroke were reduced was not evaluated. OBJECTIVE To investigate antihypertensive drug treatment effects on incidence of stroke by type and subtype, timing of strokes, case-fatality rates, stroke residual effects, and relationship of attained systolic blood pressure to stroke incidence. DESIGN The SHEP study, a randomized, double-blind, placebo-controlled trial began March 1, 1985, and had an average follow-up of 4.5 years. SETTING AND PARTICIPANTS A total of 4736 men and women aged 60 years or older with isolated systolic hypertension at 16 clinical centers in the United States. INTERVENTIONS Patients were randomly assigned to receive treatment with 12.5 mg/d of chlorthalidone (step 1); either 25 mg/d of atenolol or 0.05 mg/d of reserpine (step 2) could be added (n = 2365); or placebo (n = 2371). MAIN OUTCOME MEASURES Occurrence, type and subtype, and timing of first strokes and stroke fatalities; and change in stroke incidence for participants (whether in active treatment or placebo groups) reaching study-specific systolic blood pressure goal (decrease of at least 20 mm Hg from baseline to below 160 mm Hg) compared with participants not reaching goal. RESULTS A total of 85 and 132 participants in the active treatment and placebo groups, respectively, had ischemic strokes (adjusted relative risk [RR], 0.63; 95% confidence interval [CI], 0.48-0.82); 9 and 19 had hemorrhagic strokes (adjusted RR, 0.46; 95% CI, 0.21-1.02); and 9 and 8 had strokes of unknown type (adjusted RR, 1.05; 95% CI, 0.40-2. 73), respectively. Four subtypes of ischemic stroke were observed in active treatment and placebo group participants, respectively, as follows: for lacunar, n = 23 and n = 43 (adjusted RR, 0.53; 95% CI, 0.32-0.88); for embolic, n = 9 and n = 16 (adjusted RR, 0.56; 95% CI, 0.25-1.27); for atherosclerotic, n = 13 and n = 13 (adjusted RR, 0. 99; 95% CI, 0.46-2.15); and for unknown subtype, n = 40 and n = 60 (adjusted RR, 0.64; 95% CI, 0.43-0.96). Treatment effect was observed within 1 year for hemorrhagic strokes but was not seen until the second year for ischemic strokes. Stroke incidence significantly decreased in participants attaining study-specific systolic blood pressure goals. CONCLUSIONS In this study, antihypertensive drug treatment reduced the incidence of both hemorrhagic and ischemic (including lacunar) strokes. Reduction in stroke incidence occurred when specific systolic blood pressure goals were attained. JAMA. 2000;284:465-471
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Affiliation(s)
- H M Perry
- Washington University, Box 8048, 660 S Euclid Ave, St Louis, MO 63110, USA.
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Wassertheil-Smoller S, Fann C, Allman RM, Black HR, Camel GH, Davis B, Masaki K, Pressel S, Prineas RJ, Stamler J, Vogt TM. Relation of low body mass to death and stroke in the systolic hypertension in the elderly program. The SHEP Cooperative Research Group. Arch Intern Med 2000; 160:494-500. [PMID: 10695689 DOI: 10.1001/archinte.160.4.494] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND There are scant data on the effect of body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) on cardiovascular events and death in older patients with hypertension. OBJECTIVE To determine if low body mass in older patients with hypertension confers an increased risk of death or stroke. PATIENTS Participants were 3975 men and women (mean age, 71 years) enrolled in 17 US centers in the Systolic Hypertension in the Elderly Program trial, a randomized, double-blind, placebo-controlled clinical trial of lowdose antihypertensive therapy, with follow-up for 5 years. MAIN OUTCOME MEASURES Five-year adjusted mortality and stroke rates from Cox proportional hazards analyses. RESULTS There was no statistically significant relation of death or stroke with BMI in the placebo group (P = .47), and there was a U- or J-shaped relation in the treatment group. The J-shaped relation of death with BMI in the treated group (P = .03) showed that the lowest probability of death for men was associated with a BMI of 26.0 and for women with a BMI of 29.6; the curve was quite flat for women across a wide range of BMIs. For stroke, men and women did not differ, and the BMI nadir for both sexes combined was 29, with risk increasing steeply at BMIs below 24. Those in active treatment, however, had lower death and stroke rates compared with those taking placebo. CONCLUSIONS Among older patients with hypertension, a wide range of BMIs was associated with a similar risk of death and stroke; a low BMI was associated with increased risk. Lean, older patients with hypertension in treatment should be monitored carefully for additional risk factors.
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Affiliation(s)
- S Wassertheil-Smoller
- Department of Epidemiology and Social Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA.
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Schron EB, Wassertheil-Smoller S, Pressel S. Clinical trial participant satisfaction: survey of SHEP enrollees. SHEP Cooperative Research Group. Systolic Hypertension in the Elderly Program. J Am Geriatr Soc 1997; 45:934-8. [PMID: 9256844 DOI: 10.1111/j.1532-5415.1997.tb02962.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The purpose of this study was to determine older persons' reasons for joining a clinical trial, and to provide data that could be useful in planning and carrying out clinical trials in older and minority populations. DESIGN A survey. PARTICIPANTS The sample included 4281 men and women 60 years of age or older who were randomized to the Systolic Hypertension in the Elderly Program (SHEP). MEASUREMENTS A 10-item satisfaction/attitude questionnaire was designed to evaluate (1) what personal benefits people expect from participation in this trial, (2) motivation for joining, and (3) satisfaction with clinic staff and operations. Each question had a response category asking for a measure of agreement, satisfaction, or importance. RESULTS The most important reasons for joining the clinical trial were to contribute to science (96%), improve the health of others (96%), and improve their own health (93%). Free medical care and social aspects were less important reasons to join. There were no differences by treatment assignment, but differences in reasons for joining SHEP by age, race, gender, and education were observed. CONCLUSION Older adults were enthusiastic about clinical trial participation. Recruitment, participant management strategies, and allocation of resources should consider the needs of specific patient groups.
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Affiliation(s)
- E B Schron
- National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892-7936, USA
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