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Barbosa-Caro JC, Wudick MM. Revisiting plant electric signaling: Challenging an old phenomenon with novel discoveries. CURRENT OPINION IN PLANT BIOLOGY 2024; 79:102528. [PMID: 38552341 DOI: 10.1016/j.pbi.2024.102528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/26/2024] [Accepted: 03/08/2024] [Indexed: 05/27/2024]
Abstract
Higher plants efficiently orchestrate rapid systemic responses to diverse environmental stimuli through electric signaling. This review explores the mechanisms underlying two main types of electric signals in plants, action potentials (APs) and slow wave potentials (SWPs), and how new discoveries challenge conventional neurophysiological paradigms traditionally forming their theoretical foundations. Animal APs are biophysically well-defined, whereas plant APs are often classified based on their shape, lacking thorough characterization. SWPs are depolarizing electric signals deviating from this shape, leading to an oversimplified classification of plant electric signals. Indeed, investigating the generation and propagation of plant APs and SWPs showcases a complex interplay of mechanisms that sustain self-propagating signals and internally propagating stimuli, resulting in membrane depolarization, cytosolic calcium increase, and alterations in reactive oxygen species and pH. A holistic understanding of plant electric signaling will rely on unraveling the network of ion-conducting proteins, signaling molecules, and mechanisms for signal generation and propagation.
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Affiliation(s)
- Juan Camilo Barbosa-Caro
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Molecular Physiology, 40225 Düsseldorf, Germany
| | - Michael M Wudick
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Molecular Physiology, 40225 Düsseldorf, Germany; Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Cluster of Excellence on Plant Sciences, 40225 Düsseldorf, Germany.
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Li K, Grauschopf C, Hedrich R, Dreyer I, Konrad KR. K + and pH homeostasis in plant cells is controlled by a synchronized K + /H + antiport at the plasma and vacuolar membrane. THE NEW PHYTOLOGIST 2024; 241:1525-1542. [PMID: 38017688 DOI: 10.1111/nph.19436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/06/2023] [Indexed: 11/30/2023]
Abstract
Stomatal movement involves ion transport across the plasma membrane (PM) and vacuolar membrane (VM) of guard cells. However, the coupling mechanisms of ion transporters in both membranes and their interplay with Ca2+ and pH changes are largely unclear. Here, we investigated transporter networks in tobacco guard cells and mesophyll cells using multiparametric live-cell ion imaging and computational simulations. K+ and anion fluxes at both, PM and VM, affected H+ and Ca2+ , as changes in extracellular KCl or KNO3 concentrations were accompanied by cytosolic and vacuolar pH shifts and changes in [Ca2+ ]cyt and the membrane potential. At both membranes, the K+ transporter networks mediated an antiport of K+ and H+ . By contrast, net transport of anions was accompanied by parallel H+ transport, with differences in transport capacity for chloride and nitrate. Guard and mesophyll cells exhibited similarities in K+ /H+ transport but cell type-specific differences in [H+ ]cyt and pH-dependent [Ca2+ ]cyt signals. Computational cell biology models explained mechanistically the properties of transporter networks and the coupling of transport across the PM and VM. Our integrated approach indicates fundamental principles of coupled ion transport at membrane sandwiches to control H+ /K+ homeostasis and points to transceptor-like Ca2+ /H+ -based ion signaling in plant cells.
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Affiliation(s)
- Kunkun Li
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Christina Grauschopf
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Rainer Hedrich
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Ingo Dreyer
- Faculty of Engineering, Center of Bioinformatics, Simulation and Modeling (CBSM), University of Talca, 3460000, Talca, Chile
| | - Kai R Konrad
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
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De Rosa A, McGaughey S, Magrath I, Byrt C. Molecular membrane separation: plants inspire new technologies. THE NEW PHYTOLOGIST 2023; 238:33-54. [PMID: 36683439 DOI: 10.1111/nph.18762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Plants draw up their surrounding soil solution to gain water and nutrients required for growth, development and reproduction. Obtaining adequate water and nutrients involves taking up both desired and undesired elements from the soil solution and separating resources from waste. Desirable and undesirable elements in the soil solution can share similar chemical properties, such as size and charge. Plants use membrane separation mechanisms to distinguish between different molecules that have similar chemical properties. Membrane separation enables distribution or retention of resources and efflux or compartmentation of waste. Plants use specialised membrane separation mechanisms to adapt to challenging soil solution compositions and distinguish between resources and waste. Coordination and regulation of these mechanisms between different tissues, cell types and subcellular membranes supports plant nutrition, environmental stress tolerance and energy management. This review considers membrane separation mechanisms in plants that contribute to specialised separation processes and highlights mechanisms of interest for engineering plants with enhanced performance in challenging conditions and for inspiring the development of novel industrial membrane separation technologies. Knowledge gained from studying plant membrane separation mechanisms can be applied to developing precision separation technologies. Separation technologies are needed for harvesting resources from industrial wastes and transitioning to a circular green economy.
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Affiliation(s)
- Annamaria De Rosa
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Samantha McGaughey
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Isobel Magrath
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Caitlin Byrt
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
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Graus D, Li K, Rathje JM, Ding M, Krischke M, Müller MJ, Cuin TA, Al-Rasheid KAS, Scherzer S, Marten I, Konrad KR, Hedrich R. Tobacco leaf tissue rapidly detoxifies direct salt loads without activation of calcium and SOS signaling. THE NEW PHYTOLOGIST 2023; 237:217-231. [PMID: 36128659 DOI: 10.1111/nph.18501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
Salt stress is a major abiotic stress, responsible for declining agricultural productivity. Roots are regarded as hubs for salt detoxification, however, leaf salt concentrations may exceed those of roots. How mature leaves manage acute sodium chloride (NaCl) stress is mostly unknown. To analyze the mechanisms for NaCl redistribution in leaves, salt was infiltrated into intact tobacco leaves. It initiated pronounced osmotically-driven leaf movements. Leaf downward movement caused by hydro-passive turgor loss reached a maximum within 2 h. Salt-driven cellular water release was accompanied by a transient change in membrane depolarization but not an increase in cytosolic calcium ion (Ca2+ ) level. Nonetheless, only half an hour later, the leaves had completely regained turgor. This recovery phase was characterized by an increase in mesophyll cell plasma membrane hydrogen ion (H+ ) pumping, a salt uptake-dependent cytosolic alkalization, and a return of the apoplast osmolality to pre-stress levels. Although, transcript numbers of abscisic acid- and Salt Overly Sensitive pathway elements remained unchanged, salt adaptation depended on the vacuolar H+ /Na+ -exchanger NHX1. Altogether, tobacco leaves can detoxify sodium ions (Na+ ) rapidly even under massive salt loads, based on pre-established posttranslational settings and NHX1 cation/H+ antiport activity. Unlike roots, signaling and processing of salt stress in tobacco leaves does not depend on Ca2+ signaling.
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Affiliation(s)
- Dorothea Graus
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Kunkun Li
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Jan M Rathje
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Meiqi Ding
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Markus Krischke
- Institute for Pharmaceutical Biology, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Martin J Müller
- Institute for Pharmaceutical Biology, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Tracey Ann Cuin
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7005, Australia
| | - Khaled A S Al-Rasheid
- Zoology Department, College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Sönke Scherzer
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Irene Marten
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Kai R Konrad
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius von-Sachs Platz 2, D-97082, Würzburg, Germany
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