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Xu F, Yu F. Sensing and regulation of plant extracellular pH. TRENDS IN PLANT SCIENCE 2023; 28:1422-1437. [PMID: 37596188 DOI: 10.1016/j.tplants.2023.06.015] [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: 04/03/2023] [Revised: 06/03/2023] [Accepted: 06/19/2023] [Indexed: 08/20/2023]
Abstract
In plants, pH determines nutrient acquisition and sensing, and triggers responses to osmotic stress, whereas pH homeostasis protects the cellular machinery. Extracellular pH (pHe) controls the chemistry and rheology of the cell wall to adjust its elasticity and regulate cell expansion in space and time. Plasma membrane (PM)-localized proton pumps, cell-wall components, and cell wall-remodeling enzymes jointly maintain pHe homeostasis. To adapt to their environment and modulate growth and development, plant cells must sense subtle changes in pHe caused by the environment or neighboring cells. Accumulating evidence indicates that PM-localized cell-surface peptide-receptor pairs sense pHe. We highlight recent advances in understanding how plants perceive and maintain pHe, and discuss future perspectives.
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Affiliation(s)
- Fan Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, PR China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha 410082, PR China.
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Sena F, Kunze R. The K + transporter NPF7.3/NRT1.5 and the proton pump AHA2 contribute to K + transport in Arabidopsis thaliana under K + and NO 3- deficiency. FRONTIERS IN PLANT SCIENCE 2023; 14:1287843. [PMID: 38046603 PMCID: PMC10690419 DOI: 10.3389/fpls.2023.1287843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 10/12/2023] [Indexed: 12/05/2023]
Abstract
Nitrate (NO3 -) and potassium (K+) are distributed in plants via short and long-distance transport. These two pathways jointly regulate NO3 - and K+ levels in all higher plants. The Arabidopsis thaliana transporter NPF7.3/NRT1.5 is responsible for loading NO3 - and K+ from root pericycle cells into the xylem vessels, facilitating the long-distance transport of NO3 - and K+ to shoots. In this study, we demonstrate a protein-protein interaction of NPF7.3/NRT1.5 with the proton pump AHA2 in the plasma membrane by split ubiquitin and bimolecular complementation assays, and we show that a conserved glycine residue in a transmembrane domain of NPF7.3/NRT1.5 is crucial for the interaction. We demonstrate that AHA2 together with NRT1.5 affects the K+ level in shoots, modulates the root architecture, and alters extracellular pH and the plasma membrane potential. We hypothesize that NRT1.5 and AHA2 interaction plays a role in maintaining the pH gradient and membrane potential across the root pericycle cell plasma membrane during K+ and/or NO3 - transport.
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Affiliation(s)
- Florencia Sena
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany
- Laboratory of Apicomplexan Biology, Institut Pasteur Montevideo, Montevideo, Uruguay
- Laboratorio de Bioquímica, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Reinhard Kunze
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany
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Salt-Induced Changes in Cytosolic pH and Photosynthesis in Tobacco and Potato Leaves. Int J Mol Sci 2022; 24:ijms24010491. [PMID: 36613934 PMCID: PMC9820604 DOI: 10.3390/ijms24010491] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 12/29/2022] Open
Abstract
Salinity is one of the most common factors limiting the productivity of crops. The damaging effect of salt stress on many vital plant processes is mediated, on the one hand, by the osmotic stress caused by large concentrations of Na+ and Cl- outside the root and, on the other hand, by the toxic effect of these ions loaded in the cell. In our work, the influence of salinity on the changes in photosynthesis, transpiration, water content and cytosolic pH in the leaves of two important crops of the Solanaceae family-tobacco and potato-was investigated. Salinity caused a decrease in photosynthesis activity, which manifested as a decrease in the quantum yield of photosystem II and an increase in non-photochemical quenching. Along with photosynthesis limitation, there was a slight reduction in the relative water content in the leaves and a decrease in transpiration, determined by the crop water stress index. Furthermore, a decrease in cytosolic pH was detected in tobacco and potato plants transformed by the gene of pH-sensitive protein Pt-GFP. The potential mechanisms of the salinity influence on the activity of photosynthesis were analyzed with the comparison of the parameters' dynamics, as well as the salt content in the leaves.
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Shaebani Monazam A, Norouzian MA, Behgar M, Borzouei A, Karimzadeh H. Evaluating the role of gamma irradiation to ameliorate salt stress in corn. Int J Radiat Biol 2022; 99:523-533. [PMID: 35980744 DOI: 10.1080/09553002.2022.2110302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
PURPOSE Salt stress is a significant issue in corn cultivation leading to corn yield reduction, especially in the arid and semi-arid regions. Nuclear technologies, along with other standard methods, can be used as an efficient method for mitigating salt stress effects on plants. MATERIALS AND METHODS In this research, gamma irradiation (GI) was studied on seeds in the salt stress amelioration of corn in laboratory and field conditions. A total of five doses of gamma rays (25, 50, 100, 150 and 200 Gy) were applied to corn seeds (SC.703) at the laboratory under saline and control conditions. The best gamma-ray treatment (25 Gy) was selected for studying corn under salt stress in the field condition. RESULTS The length of the radicle, seminal roots and shoot, dry weight of radicle, and seminal roots were affected by salt stress (p <.001). However, GI affected only the radicle and seminal root length (p < .001). The radicle length was decreased as much as 3, 11, 17, 25, and 27% in 25, 50, 100, 150 and 200 Gy of GI, respectively. In addition, the seminal root length was decreased in all GI treatments except 25 Gy (p < .05). Plants derived from seeds exposed to GI (25 Gy) had a higher chlorophyll content of 1, 17, and 29% at V3 (third leaf stage), R1 (silk stage, p < .001), and R4 (dough stage, p < .001), respectively. In GI treatment, the soluble carbohydrate content was significantly higher (p < .001) at all three measurement stages and the soluble protein was significantly higher (p < .001) only at the R4 stage. Moreover, proline content was higher in GI (25 Gy) at V3 (58%, p < .05) and R1 (98%, p < .001) treatment stages. CONCLUSION Since plants from gamma-irradiated seeds had a greater plant weight and their economic traits (cob and grain weight) were higher compared to control plants under salt stress conditions, it can be concluded that a low dose of GI may ameliorate the effect of salt stress on the corn plants.
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Affiliation(s)
| | | | - Mehdi Behgar
- Agricultural Research School, Nuclear Science and Technology Research Institute, Karaj, Iran
| | - Azam Borzouei
- Agricultural Research School, Nuclear Science and Technology Research Institute, Karaj, Iran
| | - Hedayat Karimzadeh
- Agricultural Research School, Nuclear Science and Technology Research Institute, Karaj, Iran
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The Plant Defense Signal Salicylic Acid Activates the RpfB-Dependent Quorum Sensing Signal Turnover via Altering the Culture and Cytoplasmic pH in the Phytopathogen Xanthomonas campestris. mBio 2022; 13:e0364421. [PMID: 35254135 PMCID: PMC9040794 DOI: 10.1128/mbio.03644-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Plant colonization by phytopathogens is a very complex process in which numerous factors are involved. Upon infection by phytopathogens, plants produce salicylic acid (SA) that triggers gene expression within the plant to counter the invading pathogens. The present study demonstrated that SA signal also directly acts on the quorum-sensing (QS) system of the invading pathogen Xanthomonas campestris pv. campestris to affect its virulence by inducing turnover of the diffusible signaling factor (DSF) family QS signal. First, Xanthomonas campestris pv. campestris infection induces SA biosynthesis in the cabbage host plant. SA cannot be degraded by Xanthomonas campestris pv. campestris during culturing. Exogenous addition of SA or endogenous production of SA induces DSF signal turnover during late growth phase of Xanthomonas campestris pv. campestris in XYS medium that mimics plant vascular environments. Further, the DSF turnover gene rpfB is required for SA induction of DSF turnover. However, SA does not affect the expression of rpfB and DSF biosynthesis gene rpfF at the transcriptional level. SA induction of DSF turnover only occurs under acidic conditions in XYS medium. Furthermore, addition of SA to XYS medium significantly increased both culture and cytoplasmic pH. Increased cytoplasmic pH induced DSF turnover in a rpfB-dependent manner. In vitro RpfB-dependent DSF turnover activity increased when pH increased from 6 to 8. SA exposure did not affect the RpfB-dependent DSF turnover in vitro. Finally, SA-treated Xanthomonas campestris pv. campestris strain exhibited enhanced virulence when inoculated on cabbage. These results provide new insight into the roles of SA in host plants and the molecular interactions between Xanthomonas campestris pv. campestris and cruciferous plants.
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Pitann B, Bakhat HF, Fatima A, Hanstein S, Schubert S. Silicon-mediated growth promotion in maize (Zea mays L.) occurs via a mechanism that does not involve activation of the plasma membrane H +-ATPase. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 166:1121-1130. [PMID: 34328870 DOI: 10.1016/j.plaphy.2021.07.016] [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: 03/19/2021] [Revised: 07/09/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
Silicon (Si)-mediated growth promotion of various grasses is well documented. In the present study, Si-induced changes in maize shoot growth and its underlying mechanisms were studied. Maize plants were grown with various concentrations of Si (0-3 mM) in the nutrient solution. Silicon nutrition improved plant expansion growth. Silicon-supplied maize plants (0.8 and 1.2 mM) showed higher plant height and leaf area compared to no-Si amended plants. It was assumed that Si-induced expansion growth was due to positive Si effects on plasma membrane (PM) H+-ATPase. In this context, western blot analysis revealed an increase in PM H+-ATPase abundance by 77% under Si nutrition. However, in vitro measurements of enzyme activities showed no significant effect on apoplast pH, proton pumping, passive H+ efflux and enzyme kinetics such as Km, Vmax, and activation energy. Further, these results were confirmed by in vivo ratiometric analysis of apoplastic pH, which showed non-significant changes upon Si supply. In contrast, 1 mM Si altered the relative transcripts of specific PM H+-ATPase isoforms. Silicon application resulted in a significant decrease of MHA3, and this decrease in transcription seems to be compensated by an increased concentration of H+-ATPase protein. From these results, it can be concluded that changes in cell wall composition and PM H+-ATPase may be responsible for Si-mediated growth improvement in maize.
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Affiliation(s)
- Britta Pitann
- Institute of Plant Nutrition (iFZ) Justus Liebig University Giessen, Heinrich Buff-Ring 26-32, 35392, Giessen, Germany
| | - Hafiz Faiq Bakhat
- Institute of Plant Nutrition (iFZ) Justus Liebig University Giessen, Heinrich Buff-Ring 26-32, 35392, Giessen, Germany.
| | - Ammara Fatima
- Institute of Plant Nutrition (iFZ) Justus Liebig University Giessen, Heinrich Buff-Ring 26-32, 35392, Giessen, Germany
| | - Stefan Hanstein
- Institute of Plant Nutrition (iFZ) Justus Liebig University Giessen, Heinrich Buff-Ring 26-32, 35392, Giessen, Germany
| | - Sven Schubert
- Institute of Plant Nutrition (iFZ) Justus Liebig University Giessen, Heinrich Buff-Ring 26-32, 35392, Giessen, Germany
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Grunwald Y, Wigoda N, Sade N, Yaaran A, Torne T, Gosa SC, Moran N, Moshelion M. Arabidopsis leaf hydraulic conductance is regulated by xylem sap pH, controlled, in turn, by a P-type H + -ATPase of vascular bundle sheath cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:301-313. [PMID: 33735498 DOI: 10.1111/tpj.15235] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 05/28/2023]
Abstract
The leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem sap pH below 6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSC proton pump, AHA2, we now test the hypothesis that it regulates the xylem sap pH and leaf radial water fluxes. We monitored the xylem sap pH in the veins of detached leaves of wild-type Arabidopsis, AHA mutants and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor (vanadate) and stimulator (fusicoccin), and different pH buffers. We monitored their impact on the xylem sap pH and the leaf hydraulic conductance (Kleaf ), and the effect of pH on the water osmotic permeability (Pf ) of isolated BSCs protoplasts. We found that AHA2 is necessary for xylem sap acidification, and in turn, for elevating Kleaf . Conversely, AHA2 knockdown, which alkalinized the xylem sap, or, buffering its pH to 7.5, reduced Kleaf , and elevating external pH to 7.5 decreased the BSCs Pf . All these showed a causative link between AHA2 activity in BSCs and leaf radial hydraulic water conductance.
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Affiliation(s)
- Yael Grunwald
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Noa Wigoda
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Nir Sade
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences at Tel-Aviv University, Tel Aviv, 6997801, Israel
| | - Adi Yaaran
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Tanmayee Torne
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Sanbon Chaka Gosa
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Nava Moran
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Menachem Moshelion
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Siao W, Coskun D, Baluška F, Kronzucker HJ, Xu W. Root-Apex Proton Fluxes at the Centre of Soil-Stress Acclimation. TRENDS IN PLANT SCIENCE 2020; 25:794-804. [PMID: 32673580 DOI: 10.1016/j.tplants.2020.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/13/2020] [Accepted: 03/04/2020] [Indexed: 05/22/2023]
Abstract
Proton (H+) fluxes in plant roots play critical roles in maintaining root growth and facilitating plant responses to multiple soil stresses, including fluctuations in nutrient supply, salt infiltration, and water stress. Soil mining for nutrients and water, rates of nutrient uptake, and the modulation of cell expansion all depend on the regulation of root H+ fluxes, particularly at the root apex, mediated primarily by the activity of plasma membrane (PM) H+-ATPases. Here, we summarize recent findings on the regulatory mechanisms of H+ fluxes at the root apex under three abiotic stress conditions - phosphate deficiency, salinity stress, and water deficiency - and present an integrated physiomolecular view of the functions of H+ fluxes in maintaining root growth in the acclimation to soil stress.
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Affiliation(s)
- Wei Siao
- Center for Plant Water-Use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Jinshan Fuzhou 350002, China; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
| | - Devrim Coskun
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, QC G1V 0A6, Canada
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, 53115 Bonn, Germany
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010, Australia; Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Weifeng Xu
- Center for Plant Water-Use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Jinshan Fuzhou 350002, China.
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Geilfus CM. The pH of the Apoplast: Dynamic Factor with Functional Impact Under Stress. MOLECULAR PLANT 2017; 10:1371-1386. [PMID: 28987886 DOI: 10.1016/j.molp.2017.09.018] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/22/2017] [Accepted: 09/30/2017] [Indexed: 05/23/2023]
Abstract
The apoplast is an interconnected compartment with a thin water-film that alkalinizes under stress. This systemic pH increase may be a secondary effect without functional implications, arising from ion movements or proton-pump regulations. On the other hand, there are increasing indications that it is part of a mechanism to withstand stress. Regardless of this controversy, alkalinization of the apoplast has received little attention. The apoplastic pH (pHapo) increases not only during plant-pathogen interactions but also in response to salinity or drought. Not much is known about the mechanisms that cause the leaf apoplast to alkalinize, nor whether, and if so, how functional impact is conveyed. Controversial explanations have been given, and the unusual complexity of pHapo regulation is considered as the primary reason behind this lack of knowledge. A gathering of scattered information revealed that changes in pHapo convey functionality by regulating stomatal aperture via the effects exerted on abscisic acid. Moreover, apoplastic alkalinization may regulate growth under stress, whereas this needs to be verified. In this review, a comprehensive survey about several physiological mechanisms that alkalize the apoplast under stress is given, and the suitability of apoplastic alkalinization as transducing element for the transmission of sensory information is discussed.
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Affiliation(s)
- Christoph-Martin Geilfus
- Division of Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, 14195 Berlin, Germany.
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10
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Morgan SH, Lindberg S, Maity PJ, Geilfus CM, Plieth C, Mühling KH. Calcium improves apoplastic-cytosolic ion homeostasis in salt-stressed Vicia faba leaves. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:515-524. [PMID: 32480584 DOI: 10.1071/fp15381] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/17/2017] [Indexed: 06/11/2023]
Abstract
Salinity disturbs both apoplastic and cytosolic Ca2+ and pH ([Ca2+]apo, [Ca2+]cyt, pHapo and pHcyt) homeostasis, and decreases plant growth. Seedlings of Vicia faba L. cv. Fuego were cultivated in hydroponics for 7 days under control, salinity (S), extra Ca (Ca) or salinity with extra Ca (S+Ca) conditions. The [Ca2+]apo, and pHapo in the leaves were then recorded in parallel by a pseudoratiometric method, described here for the first time. Lower [Ca2+]apo and higher pHapo were obtained under salinity, whereas extra Ca supply increased the [Ca2+]apo and acidified the pHapo. Moreover, the ratiometric imaging recorded that [Ca2+]cyt and pHcyt were highest in S+Ca plants and lowest in control plants. After all pretreatments, direct addition of NaC6H11O7 to leaves induced a decrease in [Ca2+]apo in control and S+Ca plants, but not in S and Ca plants, and only slightly affected pHapo. Addition of NaCl increased [Ca2+]cyt in protoplasts from all plants but only transiently in protoplasts from S+Ca plants. Addition of NaCl decreased pHcyt in protoplasts from Ca-pretreated plants. We conclude that Ca supply improves both apoplastic and cytosolic ion homeostasis. In addition, NaC6H11O7 probably causes transport of Ca from the apoplast into the cytosol, thereby leading to a higher resting [Ca2+]cyt.
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Affiliation(s)
- Sherif H Morgan
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany
| | - Christoph Plieth
- Zentrum für Biochemie und Molekularbiologie, Universität Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Karl-Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany
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11
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Karuppanapandian T, Geilfus CM, Mühling KH, Novák O, Gloser V. Early changes of the pH of the apoplast are different in leaves, stem and roots of Vicia faba L. under declining water availability. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 255:51-58. [PMID: 28131341 DOI: 10.1016/j.plantsci.2016.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 05/10/2023]
Abstract
Changes in pH of the apoplast have recently been discussed as an important factor in adjusting transpiration and water relations under conditions of drought via modulatory effect on abscisic acid (ABA) concentration. Using Vicia faba L., we investigated whether changes in the root, shoot and leaf apoplastic pH correlated with (1) a drought-induced reduction in transpiration and with (2) changes in ABA concentration. Transpiration, leaf water potential and ABA in leaves were measured and correlated with root and shoot xylem pH, determined by a pH microelectrode, and pH of leaf apoplast quantified by microscopy-based in vivo ratiometric analysis. Results revealed that a reduction in transpiration rate in the early phase of soil drying could not be linked with changes in the apoplastic pH via effects on the stomata-regulating hormone ABA. Moreover, drought-induced increase in pH of xylem or leaf apoplast was not the remote effect of an acropetal transport of alkaline sap from root, because root xylem acidified during progressive soil drying, whereas the shoot apoplast alkalized. We reason that other, yet unknown signalling mechanism was responsible for reduction of transpiration rate in the early phase of soil drying.
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Affiliation(s)
| | - C-M Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany; Institute of Crop Science, Division of Crop Product Quality, University of Hohenheim, Emil-Wolff-Straße 25, 70599 Stuttgart, Germany
| | - K-H Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - O Novák
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany Academy of Sciences of the Czech Republic, Olomouc, Czechia
| | - V Gloser
- Department of Experimental Biology, Masaryk University, Brno, Czechia.
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Morgan SH, Maity PJ, Geilfus CM, Lindberg S, Mühling KH. Leaf ion homeostasis and plasma membrane H(+)-ATPase activity in Vicia faba change after extra calcium and potassium supply under salinity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 82:244-53. [PMID: 25010036 DOI: 10.1016/j.plaphy.2014.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 06/17/2014] [Indexed: 05/15/2023]
Abstract
Salt stress in plants impacts apoplastic ion activities and cytosolic ionic homeostasis. The ameliorating effects exerted by calcium or potassium on compartmentation of ions in leaves under salinity are not fully understood. To clarify how calcium or potassium supply could ameliorate ion homeostasis and ATPase activities under salinity, 5 mM CaSO4 or 10 mM K2SO4 were added with, or without, 100 mM NaCl for 7 d and 21 d to Vicia faba grown in hydroponics. The apoplastic pH was detected with Oregon Green dextran dye in intact second-uppermost leaves by microscopy-based ratio imaging. The cytosolic Ca(2+), Na(+), K(+) activities and pH were detected in protoplasts loaded with the acetoxy methyl-esters of Fura-2, SBFI, PBFI and BCECF, respectively, using epi-fluorescence microscopy. Furthermore, total Ca(2+), Na(+), K(+) concentrations and growth parameters were investigated. The ATPase hydrolyzing activity increased with time, but decreased after long salinity treatment. The activity largely increased in calcium-treated plants, but was depressed in potassium-treated plants after 7 d. The calcium supply increased Vmax, and the ATPase activity increased with salinity in a non-competitive way for 7 d and 21 d. The potassium supply instead decreased activity competitively with Na(+), after 21 d of salinity, with different effects on Km and Vmax. The confirmed higher ATPase activity was related with apoplast acidification, cytosol alkalinization and low cytosolic [Na(+)], and thus, might be an explanation why extra calcium improved shoot and leaf growth.
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Affiliation(s)
- Sherif H Morgan
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden; Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt.
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany.
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Karl Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany.
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Fariduddin Q, Mir BA, Ahmad A. Physiological and biochemical traits as tools to screen sensitive and resistant varieties of tomatoes exposed to salt stress. ACTA ACUST UNITED AC 2012. [DOI: 10.1590/s1677-04202012000400007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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EHLERT CHRISTINA, PLASSARD CLAUDE, COOKSON SARAHJANE, TARDIEU FRANÇOIS, SIMONNEAU THIERRY. Do pH changes in the leaf apoplast contribute to rapid inhibition of leaf elongation rate by water stress? Comparison of stress responses induced by polyethylene glycol and down-regulation of root hydraulic conductivity. PLANT, CELL & ENVIRONMENT 2011; 34:1258-66. [PMID: 21477119 DOI: 10.1111/j.1365-3040.2011.02326.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
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Geilfus CM, Mühling KH. Real-Time Imaging of Leaf Apoplastic pH Dynamics in Response to NaCl Stress. FRONTIERS IN PLANT SCIENCE 2011; 2:13. [PMID: 22639578 PMCID: PMC3355670 DOI: 10.3389/fpls.2011.00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 04/16/2011] [Indexed: 05/20/2023]
Abstract
Knowledge concerning apoplastic ion concentrations is important for the understanding of many processes in plant physiology. Ion-sensitive fluorescent probes in combination with quantitative imaging techniques offer opportunities to localize, visualize, and quantify apoplastic ion dynamics in situ. The application of this technique to the leaf apoplast is complicated because of problems associated with dye loading. We demonstrate a more sophisticated dye loading procedure that enables the mapping of spatial apoplastic ion gradients over a period of 3 h. The new technique has been used for the real-time monitoring of pH dynamics within the leaf apoplast in response to NaCl stress encountered by the roots.
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Affiliation(s)
| | - Karl H. Mühling
- Institute of Plant Nutrition and Soil Science, Christian Albrechts UniversityKiel, Germany
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Swanson SJ, Choi WG, Chanoca A, Gilroy S. In vivo imaging of Ca2+, pH, and reactive oxygen species using fluorescent probes in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2011; 62:273-97. [PMID: 21370977 DOI: 10.1146/annurev-arplant-042110-103832] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Changes in the levels of Ca(2+), pH, and reactive oxygen species (ROS) are recognized as key cellular regulators involved in diverse physiological and developmental processes in plants. Critical to understanding how they exert such widespread control is an appreciation of their spatial and temporal dynamics at levels from organ to organelle and from seconds to many hours. With appropriate controls, fluorescent sensors can provide a robust approach with which to quantify such changes in Ca(2+), pH, and ROS in real time, in vivo. The fluorescent cellular probes available for visualization split into two broad classes: (a) dyes and (b) an increasingly diverse set of genetically encoded sensors based around green fluorescent proteins (GFPs). The GFP probes in particular can be targeted to well-defined subcellular locales, offering the possibility of high-resolution mapping of these signals within the cell.
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Affiliation(s)
- Sarah J Swanson
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Geilfus CM, Zörb C, Mühling KH. Salt stress differentially affects growth-mediating β-expansins in resistant and sensitive maize (Zea mays L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2010; 48:993-8. [PMID: 20970350 DOI: 10.1016/j.plaphy.2010.09.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 09/20/2010] [Accepted: 09/22/2010] [Indexed: 05/18/2023]
Abstract
Salinity mainly reduces shoot growth by the inhibition of cell division and elongation. Expansins loosen plant cell walls. Moreover, the expression of some isoforms is clearly correlated with growth. Effects of salinity on β-expansin transcripts protein abundance were recently reported for different crop species. This study provides a broad analysis of the impact of an 8-day 100mM NaCl stress treatment on the mRNA expression of different maize (Zea mays L.) β-Expansin isoforms using real-time quantitative RT-PCR. The composite β-expansin protein expression was analyzed by western blotting using an anti-peptide antibody raised against a conserved 15-amino-acid region shared by vegetatively expressed β-expansin isoforms. For the first time, changes in β-expansin transcript and protein abundance have been analyzed together with the salinity-induced inhibition of shoot growth. A salt-resistant and a salt-sensitive cultivar were compared in order to elucidate physiological changes. Genotypic differences in the relative concentration of six β-expansin transcripts together with differences in the abundance β-expansin protein are shown in response NaCl stress. In salt-sensitive Lector, reduced β-expansin protein expression was found to correlate positively with reduced shoot growth under stress. A down-regulation of ZmExpB2, ZmExpB6, and ZmExpB8 transcripts possibly contribute to this decrease in protein abundance. In contrast, the maintenance of shoot growth in salt-resistant SR03 might be related to an unaffected abundance of growth-mediating β-expansin proteins in the shoot. Our data suggest that the up-regulation of ZmExpB2, ZmExpB6, and ZmExpB8 may sustain the stable expression of β-expansin protein under conditions of salt stress.
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Affiliation(s)
- Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
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Wakeel A, Hanstein S, Pitann B, Schubert S. Hydrolytic and pumping activity of H+-ATPase from leaves of sugar beet (Beta vulgaris L.) as affected by salt stress. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:725-31. [PMID: 20189265 DOI: 10.1016/j.jplph.2009.12.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 12/16/2009] [Accepted: 12/17/2009] [Indexed: 05/21/2023]
Abstract
Cell wall extensibility plays an important role in plant growth. According to the acid-growth theory, lower apoplastic pH allows extension growth by affecting cell wall extensibility. A lowered apoplastic pH is presumed to activate wall-loosening enzymes that control plant growth. Plasma membrane (PM) H(+)-ATPases play a major role in the apoplastic acidification by H(+) transport from cytosol to the apoplast. A salt-induced decrease in H(+)-pumping activity of plasma membrane H(+)-ATPases in salt-sensitive maize plants has previously been found. This led us to formulate the hypothesis that salt-resistant plant species such as sugar beet (Beta vulgaris L.) may have a mechanism to eliminate the effect of higher salt concentrations on plasma membrane H(+)-ATPase activity. In the present study, sugar beet plants were grown in 1mM NaCl (control) or 150 mM NaCl in hydroponics. H(+)-ATPase hydrolytic and pumping activities were measured in plasma membrane vesicles isolated from sugar beet shoots. We found that plasma membrane H(+)-ATPase hydrolytic and pumping activities were not affected by application of 150 mM NaCl. Moreover, apoplastic pH was also not affected under salt stress. However, a decrease in plant growth was observed. We assume that growth reduction was not due to a decrease in PM-H(+)-ATPase activity, but that other factors may be responsible for growth inhibition of sugar beet plants under salt stress.
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Affiliation(s)
- Abdul Wakeel
- Institute of Plant Nutrition, Interdisciplinary Research Center (IFZ), Justus Liebig University, Giessen, Germany.
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Wehr JB, Blamey FPC, Menzies NW. Comparison between methods using copper, lanthanum, and colorimetry for the determination of the cation exchange capacity of plant cell walls. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4554-4559. [PMID: 20345166 DOI: 10.1021/jf100097k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The determination of the cation exchange capacity (CEC) of plant cell walls is important for many physiological studies. We describe the determination of cell wall CEC by cation binding, using either copper (Cu) or lanthanum (La) ions, and by colorimetry. Both cations are strongly bound by cell walls, permitting fast and reproducible determinations of the CEC of small samples. However, the dye binding methods using two cationic dyes, Methylene Blue and Toluidine Blue, overestimated the CEC several-fold. Column and centrifugation methods are proposed for CEC determination by Cu or La binding; both provide similar results. The column method involves packing plant material (2-10 mg dry mass) in a chromatography column (10 mL) and percolating with 20 bed volumes of 1 mM La or Cu solution, followed by washing with deionized water. The centrifugation method uses a suspension of plant material (1-2 mL) that is centrifuged, and the pellet is mixed three times with 10 pellet volumes of 1 mM La or Cu solution followed by centrifugation and final washing with deionized water. In both methods the amount of La or Cu bound to the material was determined by spectroscopic methods.
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Affiliation(s)
- J Bernhard Wehr
- School of Land, Crop and Food Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
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