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Chugh M, Munjal A, Megason SG. Hydrostatic pressure as a driver of cell and tissue morphogenesis. Semin Cell Dev Biol 2022; 131:134-145. [PMID: 35534334 PMCID: PMC9529827 DOI: 10.1016/j.semcdb.2022.04.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/24/2022] [Accepted: 04/27/2022] [Indexed: 12/14/2022]
Abstract
Morphogenesis, the process by which tissues develop into functional shapes, requires coordinated mechanical forces. Most current literature ascribes contractile forces derived from actomyosin networks as the major driver of tissue morphogenesis. Recent works from diverse species have shown that pressure derived from fluids can generate deformations necessary for tissue morphogenesis. In this review, we discuss how hydrostatic pressure is generated at the cellular and tissue level and how the pressure can cause deformations. We highlight and review findings demonstrating the mechanical roles of pressures from fluid-filled lumens and viscous gel-like components of the extracellular matrix. We also emphasise the interactions and mechanochemical feedbacks between extracellular pressures and tissue behaviour in driving tissue remodelling. Lastly, we offer perspectives on the open questions in the field that will further our understanding to uncover new principles of tissue organisation during development.
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Affiliation(s)
- Mayank Chugh
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
| | - Akankshi Munjal
- Department of Cell Biology, Duke University School of Medicine, Nanaline Duke Building, 307 Research Drive, Durham, NC 27710, USA.
| | - Sean G Megason
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
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2
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Valenzuela FJ, Reineke D, Leventini D, Chen CCL, Barrett-Lennard EG, Colmer TD, Dodd IC, Shabala S, Brown P, Bazihizina N. Plant responses to heterogeneous salinity: agronomic relevance and research priorities. ANNALS OF BOTANY 2022; 129:499-518. [PMID: 35171228 PMCID: PMC9007098 DOI: 10.1093/aob/mcac022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/14/2022] [Indexed: 06/12/2023]
Abstract
BACKGROUND Soil salinity, in both natural and managed environments, is highly heterogeneous, and understanding how plants respond to this spatiotemporal heterogeneity is increasingly important for sustainable agriculture in the era of global climate change. While the vast majority of research on crop response to salinity utilizes homogeneous saline conditions, a much smaller, but important, effort has been made in the past decade to understand plant molecular and physiological responses to heterogeneous salinity mainly by using split-root studies. These studies have begun to unravel how plants compensate for water/nutrient deprivation and limit salt stress by optimizing root-foraging in the most favourable parts of the soil. SCOPE This paper provides an overview of the patterns of salinity heterogeneity in rain-fed and irrigated systems. We then discuss results from split-root studies and the recent progress in understanding the physiological and molecular mechanisms regulating plant responses to heterogeneous root-zone salinity and nutrient conditions. We focus on mechanisms by which plants (salt/nutrient sensing, root-shoot signalling and water uptake) could optimize the use of less-saline patches within the root-zone, thereby enhancing growth under heterogeneous soil salinity conditions. Finally, we place these findings in the context of defining future research priorities, possible irrigation management and crop breeding opportunities to improve productivity from salt-affected lands.
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Affiliation(s)
| | - Daniela Reineke
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Dante Leventini
- Department of Plant Sciences, University of California, Davis, CA, USA
| | | | - Edward G Barrett-Lennard
- Land Management Group, Agriculture Discipline, College of Science, Health, Engineering and Education, Murdoch University, WA, Australia
- Department of Primary Industries and Regional Development, South Perth, WA, Australia
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, The University of Western Australia, Crawley, WA, Australia
- Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - Ian C Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Sergey Shabala
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS 7001, Australia
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
| | - Patrick Brown
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Nadia Bazihizina
- Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
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3
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Tyerman SD, McGaughey SA, Qiu J, Yool AJ, Byrt CS. Adaptable and Multifunctional Ion-Conducting Aquaporins. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:703-736. [PMID: 33577345 DOI: 10.1146/annurev-arplant-081720-013608] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
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Affiliation(s)
- Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Samantha A McGaughey
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
| | - Jiaen Qiu
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Andrea J Yool
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia 5005, Australia;
| | - Caitlin S Byrt
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
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4
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Vitali V, Sutka M, Ojeda L, Aroca R, Amodeo G. Root hydraulics adjustment is governed by a dominant cell-to-cell pathway in Beta vulgaris seedlings exposed to salt stress. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 306:110873. [PMID: 33775369 DOI: 10.1016/j.plantsci.2021.110873] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
Soil salinity reduces root hydraulic conductivity (Lpr) of several plant species. However, how cellular signaling and root hydraulic properties are linked in plants that can cope with water restriction remains unclear. In this work, we exposed the halotolerant species red beet (Beta vulgaris) to increasing concentrations of NaCl to determine the components that might be critical to sustaining the capacity to adjust root hydraulics. Our strategy was to use both hydraulic and cellular approaches in hydroponically grown seedlings during the first osmotic phase of salt stress. Interestingly, Lpr presented a bimodal profile response apart from the magnitude of the imposed salt stress. As well as Lpr, the PIP2-aquaporin profile follows an unphosphorylated/phosphorylated pattern when increasing NaCl concentration while PIP1 aquaporins remain constant. Lpr also shows high sensitivity to cycloheximide. In low NaCl concentrations, Lpr was high and 70 % of its capacity could be attributed to the CHX-inhibited cell-to-cell pathway. More interestingly, roots can maintain a constant spontaneous exudated flow that is independent of the applied NaCl concentration. In conclusion, Beta vulgaris root hydraulic adjustment completely lies in a dominant cell-to-cell pathway that contributes to satisfying plant water demands.
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Affiliation(s)
- Victoria Vitali
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales & Instituto de Biodiversidad, Biología Experimental y Aplicada, Universidad de Buenos Aires and Consejo Nacional de Investigaciones Científicas y Técnicas, C1428EGA, Buenos Aires, Argentina
| | - Moira Sutka
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales & Instituto de Biodiversidad, Biología Experimental y Aplicada, Universidad de Buenos Aires and Consejo Nacional de Investigaciones Científicas y Técnicas, C1428EGA, Buenos Aires, Argentina
| | - Lucas Ojeda
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales & Instituto de Biodiversidad, Biología Experimental y Aplicada, Universidad de Buenos Aires and Consejo Nacional de Investigaciones Científicas y Técnicas, C1428EGA, Buenos Aires, Argentina
| | - Ricardo Aroca
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (EEZ-CSIC), Profesor Albareda 1, 18008, Granada, Spain
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales & Instituto de Biodiversidad, Biología Experimental y Aplicada, Universidad de Buenos Aires and Consejo Nacional de Investigaciones Científicas y Técnicas, C1428EGA, Buenos Aires, Argentina.
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5
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Knipfer T, Danjou M, Vionne C, Fricke W. Salt stress reduces root water uptake in barley (Hordeum vulgare L.) through modification of the transcellular transport path. PLANT, CELL & ENVIRONMENT 2021; 44:458-475. [PMID: 33140852 DOI: 10.1111/pce.13936] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/24/2020] [Indexed: 05/21/2023]
Abstract
The aim of the study was to understand the hydraulic response to salt stress of the root system of the comparatively salt-tolerant crop barley (Hordeum vulgare L.). We focused on the transcellular path of water movement across the root cylinder that involves the crossing of membranes. This path allows for selective water uptake, while excluding salt ions. Hydroponically grown plants were exposed to 100 mM NaCl for 5-7 days and analysed when 15-17 days old. A range of complementary and novel approaches was used to determine hydraulic conductivity (Lp). This included analyses at cell, root and plant level and modelling of water flow. Apoplastic barrier formation and gene expression level of aquaporins (AQPs) was analysed. Salt stress reduced the Lp of root system through reducing water flow along the transcellular path. This involved changes in the activity and gene expression level of AQPs. Modelling of root-Lp showed that the reduction in root-Lp did not require added hydraulic resistances through apoplastic barriers at the endodermis. The bulk of data points to a near-perfect semi-permeability of roots of control plants (solute reflection coefficient σ ~1.0). Roots of salt-stressed plants are almost as semi-permeable (σ > 0.8).
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Affiliation(s)
- Thorsten Knipfer
- School of Biology and Environmental Sciences, University College Dublin, Dublin, Ireland
- Department of Viticulture & Enology, University of California, Davis, California, USA
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Mathieu Danjou
- School of Biology and Environmental Sciences, University College Dublin, Dublin, Ireland
| | - Charles Vionne
- School of Biology and Environmental Sciences, University College Dublin, Dublin, Ireland
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin, Dublin, Ireland
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Volkov V, Schwenke H. A Quest for Mechanisms of Plant Root Exudation Brings New Results and Models, 300 Years after Hales. PLANTS 2020; 10:plants10010038. [PMID: 33375713 PMCID: PMC7823307 DOI: 10.3390/plants10010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/20/2020] [Accepted: 12/21/2020] [Indexed: 12/27/2022]
Abstract
The review summarizes some of our current knowledge on the phenomenon of exudation from the cut surface of detached roots with emphasis on results that were mostly established over the last fifty years. The phenomenon is quantitatively documented in the 18th century (by Hales in 1727). By the 19th century, theories mainly ascribed exudation to the secretion of living root cells. The 20th century favored the osmometer model of root exudation. Nevertheless, growing insights into the mechanisms of water transport and new or rediscovered observations stimulated the quest for a more adequate exudation model. The historical overview shows how understanding of exudation changed with time following experimental opportunities and novel ideas from different areas of knowledge. Later theories included cytoskeleton-dependent micro-pulsations of turgor in root cells to explain the observed water exudation. Recent progress in experimental biomedicine led to detailed study of channels and transporters for ion transport via cellular membranes and to the discovery of aquaporins. These universal molecular entities have been incorporated to the more complex models of water transport via plant roots. A new set of ideas and explanations was based on cellular osmoregulation by mechanosensitive ion channels. Thermodynamic calculations predicted the possibility of water transport against osmotic forces based on co-transport of water with ions via cation-chloride cotransporters. Recent observations of rhizodermis exudation, exudation of roots without an external aqueous medium, segments cut from roots, pulses of exudation, a phase shifting of water uptake and exudation, and of effects of physiologically active compounds (like ion channel blockers, metabolic agents, and cytoskeletal agents) will likely refine our understanding of the phenomenon. So far, it seems that more than one mechanism is responsible for root pressure and root exudation, processes which are important for refilling of embolized xylem vessels. However, recent advances in ion and water transport research at the molecular level suggest potential future directions to understanding of root exudation and new models awaiting experimental testing.
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Affiliation(s)
- Vadim Volkov
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California, Davis, CA 95616, USA
- K.A. Timiriazev Institute of Plant Physiology RAS, 35 Botanicheskaya St., Moscow 127276, Russia
- Correspondence: (V.V.); (H.S.)
| | - Heiner Schwenke
- Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany
- Correspondence: (V.V.); (H.S.)
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Foster KJ, Miklavcic SJ. A Comprehensive Biophysical Model of Ion and Water Transport in Plant Roots. III. Quantifying the Energy Costs of Ion Transport in Salt-Stressed Roots of Arabidopsis. FRONTIERS IN PLANT SCIENCE 2020; 11:865. [PMID: 32719693 PMCID: PMC7348042 DOI: 10.3389/fpls.2020.00865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 05/27/2020] [Indexed: 05/15/2023]
Abstract
Salt stress defense mechanisms in plant roots, such as active Na+ efflux and storage, require energy in the form of ATP. Understanding the energy required for these transport mechanisms is an important step toward achieving an understanding of salt tolerance. However, accurate measurements of the fluxes required to estimate these energy costs are difficult to achieve by experimental means. As a result, the magnitude of the energy costs of ion transport in salt-stressed roots relative to the available energy is unclear, as are the relative contributions of different defense mechanisms to the total cost. We used mathematical modeling to address three key questions about the energy costs of ion transport in salt-stressed Arabidopsis roots: are the energy requirements calculated on the basis of flux data feasible; which transport steps are the main contributors to the total energy costs; and which transport processes could be altered to minimize the total energy costs? Using our biophysical model of ion and water transport we calculated the energy expended in the trans-plasma membrane and trans-tonoplast transport of Na+, K+, Cl-, and H+ in different regions of a salt-stressed model Arabidopsis root. Our calculated energy costs exceeded experimental estimates of the energy supplied by root respiration for high external NaCl concentrations. We found that Na+ exclusion from, and Cl- uptake into, the outer root were the major contributors to the total energy expended. Reducing the leakage of Na+ and the active uptake of Cl- across outer root plasma membranes would lower energy costs while enhancing exclusion of these ions. The high energy cost of ion transport in roots demonstrates that the energetic consequences of altering ion transport processes should be considered when attempting to improve salt tolerance.
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Affiliation(s)
| | - Stanley J. Miklavcic
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, WA, Australia
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8
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Arsova B, Foster KJ, Shelden MC, Bramley H, Watt M. Dynamics in plant roots and shoots minimize stress, save energy and maintain water and nutrient uptake. THE NEW PHYTOLOGIST 2020; 225:1111-1119. [PMID: 31127613 DOI: 10.1111/nph.15955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/19/2019] [Indexed: 05/12/2023]
Abstract
Plants are inherently dynamic. Dynamics minimize stress while enabling plants to flexibly acquire resources. Three examples are presented for plants tolerating saline soil: transport of sodium chloride (NaCl), water and macronutrients is nonuniform along a branched root; water and NaCl redistribute between shoot and soil at night-time; and ATP for salt exclusion is much lower in thinner branch roots than main roots, quantified using a biophysical model and geometry from anatomy. Noninvasive phenotyping and precision agriculture technologies can be used together to harness plant dynamics, but analytical methods are needed. A plant advancing in time through a soil and atmosphere space is proposed as a framework for dynamic data and their relationship to crop improvement.
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Affiliation(s)
- Borjana Arsova
- Root Dynamics Group, Institute for Bio and Geosciences-2, Plant Sciences, Forschungszentrum Juelich GmbH, Juelich, 52428, Germany
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Megan C Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Helen Bramley
- School of Life and Environmental Sciences, Plant Breeding Institute and Sydney Institute of Agriculture, The University of Sydney, Narrabri, NSW, 2390, Australia
| | - Michelle Watt
- Root Dynamics Group, Institute for Bio and Geosciences-2, Plant Sciences, Forschungszentrum Juelich GmbH, Juelich, 52428, Germany
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9
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Munns R, Day DA, Fricke W, Watt M, Arsova B, Barkla BJ, Bose J, Byrt CS, Chen ZH, Foster KJ, Gilliham M, Henderson SW, Jenkins CLD, Kronzucker HJ, Miklavcic SJ, Plett D, Roy SJ, Shabala S, Shelden MC, Soole KL, Taylor NL, Tester M, Wege S, Wegner LH, Tyerman SD. Energy costs of salt tolerance in crop plants. THE NEW PHYTOLOGIST 2020; 225:1072-1090. [PMID: 31004496 DOI: 10.1111/nph.15864] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/25/2019] [Indexed: 05/21/2023]
Abstract
Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H+ -ATPase also is a critical component. One proposed leak, that of Na+ influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na+ and Cl- concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components.
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Affiliation(s)
- Rana Munns
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin (UCD), Dublin, 4, Ireland
| | - Michelle Watt
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Borjana Arsova
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2481, Australia
| | - Jayakumar Bose
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Caitlin S Byrt
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Zhong-Hua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Matthew Gilliham
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Sam W Henderson
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Urrbrae, SA, 5064, Australia
| | - Colin L D Jenkins
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Darren Plett
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stuart J Roy
- Australian Research Council (ARC) Industrial Transformation Research Hub for Wheat in a Hot and Dry Climate, School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Sergey Shabala
- Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, Tas., 7001, Australia
- International Centre for Environmental Membrane Biology, Foshan University, Foshan, 528000, China
| | - Megan C Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Kathleen L Soole
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Nicolas L Taylor
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Molecular Sciences and Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Mark Tester
- Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Stefanie Wege
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Lars H Wegner
- Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology (IHM), D-76344, Eggenstein-Leopoldshafen, Germany
| | - Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
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10
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Wegner LH, Shabala S. Biochemical pH clamp: the forgotten resource in membrane bioenergetics. THE NEW PHYTOLOGIST 2020; 225:37-47. [PMID: 31393010 DOI: 10.1111/nph.16094] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 08/01/2019] [Indexed: 05/08/2023]
Abstract
Solute uptake and release by plant cells are frequently energized by coupling to H+ influx supported by the proton motive force (pmf). The pmf results from a stable pH difference between the apoplast and the cytosol, with bulk values ranging from 4.9 to 5.8 and from 7.1 to 7.5, respectively, in combination with a negative electrical membrane potential. The P-type H+ ATPases pumping H+ from the cytosol into the apoplast at the expense of ATP hydrolysis are generally viewed as the only pmf source, exclusively linking membrane transport to energy metabolism. However, recent evidence suggests that pump activity may be insufficient to energize transport, particularly under stress conditions. Indeed, cytosolic H+ scavenging and apoplastic H+ generation by metabolism (denoted as 'active' buffering in contrast to the readily exhausted 'passive' matrix buffering) also stabilize the pH gradient. In the cytosol, H+ scavenging is mainly associated with malate decarboxylation catalyzed by malic enzyme, and via the GABA shunt of the tricarboxylic acid (TCA) cycle involving glutamate decarboxylation. In the apoplast, formation of bicarbonate from CO2 , the end-product of respiration, generates H+ at pH ≥ 6. Membrane potential is stabilized by K+ release and/or by anion uptake via ion channels. Finally, thermodynamic aspects of active buffering are discussed.
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Affiliation(s)
- Lars H Wegner
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
| | - Sergey Shabala
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
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11
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Foster KJ, Miklavcic SJ. A Comprehensive Biophysical Model of Ion and Water Transport in Plant Roots. II. Clarifying the Roles of SOS1 in the Salt-Stress Response in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2019; 10:1121. [PMID: 31620152 PMCID: PMC6759596 DOI: 10.3389/fpls.2019.01121] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/14/2019] [Indexed: 05/15/2023]
Abstract
SOS1 transporters play an essential role in plant salt tolerance. Although SOS1 is known to encode a plasma membrane Na+/H+ antiporter, the transport mechanisms by which these transporters contribute to salt tolerance at the level of the whole root are unclear. Gene expression and flux measurements have provided conflicting evidence for the location of SOS1 transporter activity, making it difficult to determine their function. Whether SOS1 transporters load or unload Na+ from the root xylem transpiration stream is also disputed. To address these areas of contention, we applied a mathematical model to answer the question: what is the function of SOS1 transporters in salt-stressed Arabidopsis roots? We used our biophysical model of ion and water transport in a salt-stressed root to simulate a wide range of SOS1 transporter locations in a model Arabidopsis root, providing a level of detail that cannot currently be achieved by experimentation. We compared our simulations with available experimental data to find reasonable parameters for the model and to determine likely locations of SOS1 transporter activity. We found that SOS1 transporters are likely to be operating in at least one tissue of the outer mature root, in the mature stele, and in the epidermis of the root apex. SOS1 transporter activity in the mature outer root cells is essential to maintain low cytosolic Na+ levels in the root and also restricts the uptake of Na+ to the shoot. SOS1 transporters in the stele actively load Na+ into the xylem transpiration stream, enhancing the transport of Na+ and water to the shoot. SOS1 transporters acting in the apex restrict cytosolic Na+ concentrations in the apex but are unable to maintain low cytosolic Na+ levels in the mature root. Our findings suggest that targeted, tissue-specific overexpression or knockout of SOS1 may lead to greater salt tolerance than has been achieved with constitutive gene changes. Tissue-specific changes to the expression of SOS1 could be used to identify the appropriate balance between limiting Na+ uptake to the shoot while maintaining water uptake, potentially leading to enhancements in salt tolerance.
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Tyerman SD, Munns R, Fricke W, Arsova B, Barkla BJ, Bose J, Bramley H, Byrt C, Chen Z, Colmer TD, Cuin T, Day DA, Foster KJ, Gilliham M, Henderson SW, Horie T, Jenkins CLD, Kaiser BN, Katsuhara M, Plett D, Miklavcic SJ, Roy SJ, Rubio F, Shabala S, Shelden M, Soole K, Taylor NL, Tester M, Watt M, Wege S, Wegner LH, Wen Z. Energy costs of salinity tolerance in crop plants. THE NEW PHYTOLOGIST 2019; 221:25-29. [PMID: 30488600 DOI: 10.1111/nph.15555] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Rana Munns
- ARC Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin (UCD), Dublin, 4, Ireland
| | - Borjana Arsova
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Jülich, Wilhelm-Johnen Strasse, 52425, Jülich, Germany
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Jayakumar Bose
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Helen Bramley
- Plant Breeding Institute, Sydney Institute of Agriculture & School of Life and Environmental Sciences, The University of Sydney, Narrabri, NSW, 2390, Australia
| | - Caitlin Byrt
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Zhonghua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Timothy D Colmer
- School of Agriculture and Environment, ARC Industrial Transformation Research Hub on Legumes for Sustainable Agriculture, Faculty of Science, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Tracey Cuin
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, 7001, Australia
| | - David A Day
- College of Science & Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Matthew Gilliham
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Sam W Henderson
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
- CSIRO Agriculture and Food, Urrbrae, SA, 5064, Australia
| | - Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567, Japan
| | - Colin L D Jenkins
- College of Sciences and Engineering, Flinders University of South Australia, Bedford Park, SA, 5042, Australia
| | - Brent N Kaiser
- School of Life and Environmental Science, University of Sydney, Camden, NSW, 2570, Australia
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 7100046, Japan
| | - Darren Plett
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
- School of Agriculture and Food, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Stuart J Roy
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Francisco Rubio
- Departamento de Nutrición Vegetal, CEBAS-CSIC-Campus de Espinardo, 30100, Murcia, Spain
| | - Sergey Shabala
- College of Science and Engineering, University of Tasmania, Private Bag 54, Hobart, TAS, 7001, Australia
| | - Megan Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Kathleen Soole
- College of Sciences and Engineering, Flinders University of South Australia, Bedford Park, SA, 5042, Australia
| | - Nicolas L Taylor
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences and Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Mark Tester
- Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Michelle Watt
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Stefanie Wege
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Lars H Wegner
- Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, D-76344, Eggenstein-Leopoldshafen, Germany
| | - Zhengyu Wen
- School of Life and Environmental Science, University of Sydney, Camden, NSW, 2570, Australia
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Henderson SW, Wege S, Gilliham M. Plant Cation-Chloride Cotransporters (CCC): Evolutionary Origins and Functional Insights. Int J Mol Sci 2018; 19:E492. [PMID: 29415511 PMCID: PMC5855714 DOI: 10.3390/ijms19020492] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 01/01/2023] Open
Abstract
Genomes of unicellular and multicellular green algae, mosses, grasses and dicots harbor genes encoding cation-chloride cotransporters (CCC). CCC proteins from the plant kingdom have been comparatively less well investigated than their animal counterparts, but proteins from both plants and animals have been shown to mediate ion fluxes, and are involved in regulation of osmotic processes. In this review, we show that CCC proteins from plants form two distinct phylogenetic clades (CCC1 and CCC2). Some lycophytes and bryophytes possess members from each clade, most land plants only have members of the CCC1 clade, and green algae possess only the CCC2 clade. It is currently unknown whether CCC1 and CCC2 proteins have similar or distinct functions, however they are both more closely related to animal KCC proteins compared to NKCCs. Existing heterologous expression systems that have been used to functionally characterize plant CCC proteins, namely yeast and Xenopus laevis oocytes, have limitations that are discussed. Studies from plants exposed to chemical inhibitors of animal CCC protein function are reviewed for their potential to discern CCC function in planta. Thus far, mutations in plant CCC genes have been evaluated only in two species of angiosperms, and such mutations cause a diverse array of phenotypes-seemingly more than could simply be explained by localized disruption of ion transport alone. We evaluate the putative roles of plant CCC proteins and suggest areas for future investigation.
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Affiliation(s)
- Sam W Henderson
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia.
| | - Stefanie Wege
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia.
| | - Matthew Gilliham
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia.
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