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Jain D, Schmidt W. Protein Phosphorylation Orchestrates Acclimations of Arabidopsis Plants to Environmental pH. Mol Cell Proteomics 2024; 23:100685. [PMID: 38000714 PMCID: PMC10837763 DOI: 10.1016/j.mcpro.2023.100685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 10/18/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
Environment pH (pHe) is a key parameter dictating a surfeit of conditions critical to plant survival and fitness. To elucidate the mechanisms that recalibrate cytoplasmic and apoplastic pH homeostasis, we conducted a comprehensive proteomic/phosphoproteomic inventory of plants subjected to transient exposure to acidic or alkaline pH, an approach that covered the majority of protein-coding genes of the reference plant Arabidopsis thaliana. Our survey revealed a large set-of so far undocumented pHe-dependent phospho-sites, indicative of extensive post-translational regulation of proteins involved in the acclimation to pHe. Changes in pHe altered both electrogenic H+ pumping via P-type ATPases and H+/anion co-transport processes, putatively leading to altered net trans-plasma membrane translocation of H+ ions. In pH 7.5 plants, the transport (but not the assimilation) of nitrogen via NRT2-type nitrate and AMT1-type ammonium transporters was induced, conceivably to increase the cytosolic H+ concentration. Exposure to both acidic and alkaline pH resulted in a marked repression of primary root elongation. No such cessation was observed in nrt2.1 mutants. Alkaline pH decreased the number of root hairs in the wild type but not in nrt2.1 plants, supporting a role of NRT2.1 in developmental signaling. Sequestration of iron into the vacuole via alterations in protein abundance of the vacuolar iron transporter VTL5 was inversely regulated in response to high and low pHe, presumptively in anticipation of associated changes in iron availability. A pH-dependent phospho-switch was also observed for the ABC transporter PDR7, suggesting changes in activity and, possibly, substrate specificity. Unexpectedly, the effect of pHe was not restricted to roots and provoked pronounced changes in the shoot proteome. In both roots and shoots, the plant-specific TPLATE complex components AtEH1 and AtEH2-essential for clathrin-mediated endocytosis-were differentially phosphorylated at multiple sites in response to pHe, indicating that the endocytic cargo protein trafficking is orchestrated by pHe.
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Affiliation(s)
- Dharmesh Jain
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan; Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wolfgang Schmidt
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Biotechnology Center, National Chung-Hsing University, Taichun, Taiwan; Genome and Systems Biology Degree Program, College of Life Science, National Taiwan University, Taipei, Taiwan.
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Yao XC, Meng LF, Zhao WL, Mao GL. Changes in the morphology traits, anatomical structure of the leaves and transcriptome in Lycium barbarum L. under salt stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1090366. [PMID: 36890891 PMCID: PMC9987590 DOI: 10.3389/fpls.2023.1090366] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Salt stress directly affects the growth of plants. The limitation of leaf grow is among the earliest visible effects of salt stress. However, the regulation mechanism of salt treatments on leaf shape has not been fully elucidated. We measured the morphological traits and anatomical structure. In combination with transcriptome analysis, we analyzed differentially expressed genes (DEGs) and verified the RNA-seq data by qRT-PCR. Finally, we analyzed correlation between leaf microstructure parameters and expansin genes. We show that the leaf thickness, the width, and the leaf length significantly increased at elevated salt concentrations after salt stress for 7 days. Low salt mainly promoted the increase in leaves length and width, but high salt concentration accelerated the leaf thickness. The anatomical structure results indicated that palisade mesophyll tissues contribute more to leaf thickness than spongy mesophyll tissues, which possibly contributed to the increase in leaf expansion and thickness. Moreover, a total of 3,572 DEGs were identified by RNA-seq. Notably, six of the DEGs among 92 identified genes concentrated on cell wall synthesis or modification were involved in cell wall loosening proteins. More importantly, we demonstrated that there was a strong positive correlation between the upregulated EXLA2 gene and the thickness of the palisade tissue in L. barbarum leaves. These results suggested that salt stress possibly induced the expression of EXLA2 gene, which in turn increased the thickness of L. barbarum leaves by promoting the longitudinal expansion of cells of the palisade tissue. This study lays a solid knowledge for revealing the underlying molecular mechanisms of leaf thickening in L. barbarum in response to salt stresses.
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Kaiser H, Sagervanshi A, Mühling KH. A method to experimentally clamp leaf water content to defined values to assess its effects on apoplastic pH. PLANT METHODS 2022; 18:72. [PMID: 35644610 PMCID: PMC9150304 DOI: 10.1186/s13007-022-00905-y] [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: 12/20/2021] [Accepted: 05/08/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Leaf hydration is controlled by feedback mechanisms, e.g. stomatal responses, adjustments of osmotic potential and hydraulic conductivity. Leaf water content thus is an input into related feedback-loops controlling the balance of water uptake and loss. Apoplastic alkalisation upon leaf dehydration is hypothesized to be involved together and in interaction with abscisic acid (ABA) in water stress related signaling on tissue level. However, important questions are still unresolved, e.g. the mechanisms leading to pH changes and the exact nature of its interaction with ABA. When studying these mechanisms and their intermediate signaling steps, an experimenter has only poor means to actually control the central experimental variable, leaf water content (LWC), because it is not only dependent on external variables (e.g. air humidity), which are under experimental control, but is also governed by the biological influences controlling transpiration and water uptake. Those are often unknown in their magnitude, unpredictable and fluctuating throughout an experiment and will prevent true repetitions of an experiment. The goal of the method presented here is to experimentally control and manipulate leaf water content (LWC) of attached intact leaves enclosed in a cuvette while simultaneously measuring physiological parameters like, in this case, apoplastic pH. RESULTS An experimental setup was developed where LWC is measured by a sensor based on IR-transmission and its signal processed to control a pump which circulates air from the cuvette through a cold trap. Hereby a feedback-loop is formed, which by adjusting vapour pressure deficit (VPD) and consequently leaf transpiration can precisely control LWC. This technique is demonstrated here in a combination with microscopic fluorescence imaging of apoplastic pH (pHapo) as indicated by the excitation ratio of the pH sensitive dye OregonGreen. Initial results indicate that pHapo of the adaxial epidermis of Vicia faba is linearly related to reductions in LWC. CONCLUSIONS Using this setup, constant LWC levels, step changes or ramps can be experimentally applied while simultaneously measuring physiological responses. The example experiments demonstrate that bringing LWC under experimental control in this way allows better controlled and more repeatable experiments to probe quantitative relationships between LWC and signaling and regulatory processes.
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Affiliation(s)
- Hartmut Kaiser
- Institut Für Pflanzenernährung and Bodenkunde, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Straße 2, 24098, Kiel, Germany.
- Botanisches Institut und Botanischer Garten der Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 7, 24098, Kiel, Germany.
| | - Amit Sagervanshi
- Institut Für Pflanzenernährung and Bodenkunde, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Straße 2, 24098, Kiel, Germany
| | - Karl H Mühling
- Institut Für Pflanzenernährung and Bodenkunde, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Straße 2, 24098, Kiel, Germany
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Sagervanshi A, Naeem A, Geilfus CM, Kaiser H, Mühling KH. One-time abscisic acid priming induces long-term salinity resistance in Vicia faba: Changes in key transcripts, metabolites, and ionic relations. PHYSIOLOGIA PLANTARUM 2021; 172:146-161. [PMID: 33314239 DOI: 10.1111/ppl.13315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/30/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Abscisic acid (ABA) priming is known to enhance plant growth and survival under salinity. However, the mechanisms mediating this long-term acclimatization to salt stress are still obscure. Specifically, the long-term transcriptional changes and their effects on ion relations were never investigated. This motivated us to study the long-term (8 days) effect of one-time 24 h root priming treatment with 10 μM ABA on transcription levels of relevant regulated key genes, osmotically relevant metabolites, and ionic concentrations in Vicia faba grown under 50 mM NaCl salinity. The novelty of this study is that we could demonstrate long-term effects of a one-time ABA application. ABA-priming was found to prevent the salt-induced decline in root and shoot dry matter, improved photosynthesis, and inhibited terminal wilting of plants. It substantially increased the mRNA level of AAPK and 14-3-3 ABA inducible kinases and ion transporters (PM H+ -ATPase, VFK1, KUP7, SOS1, and CLC1). These ABA-induced transcriptional changes went along with altered tissue ion patterns. Primed plants accumulated less Na+ and Cl- but more K+ , Ca2+ , Zn2+ , Fe2+ , Mn2+ , NO3 - , and SO4 2- . Priming changed the composition pattern of organic osmolytes under salinity, with glucose and fructose being dominant in unprimed, whereas sucrose was dominant in the primed plants. We conclude that one-time ABA priming mitigates salt stress in Vicia faba by persistently changing transcription patterns of key genes, stabilizing the ionic and osmotic balance, and improving photosynthesis and growth.
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Affiliation(s)
- Amit Sagervanshi
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - Asif Naeem
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
- Division of Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Berlin, Germany
| | - Hartmut Kaiser
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - Karl H Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
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Geilfus CM, Zhang X, Mithöfer A, Burgel L, Bárdos G, Zörb C. Leaf apoplastic alkalization promotes transcription of the ABA-synthesizing enzyme Vp14 and stomatal closure in Zea mays. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2686-2695. [PMID: 33345268 PMCID: PMC8006549 DOI: 10.1093/jxb/eraa589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
The chloride component of NaCl salinity causes the leaf apoplast to transiently alkalinize. This transition in pH reduces stomatal aperture. However, whether this apoplastic pH (pHapo) transient initiates stomatal closure by interacting with other chloride stress-induced responses or whether the pH transient alone initiates stomatal closure is unknown. To clarify the problem, the transient alkalinization of the leaf apoplast was mimicked in intact maize (Zea mays L.) by infiltrating near-neutral pH buffers into the leaf apoplast. Effects of the pHapo transient could thus be investigated independently from other chloride stress-derived effects. Microscopy-based ratiometric live pHapo imaging was used to monitor pHapoin planta. LC-MS/MS and real-time quantitative reverse transcription-PCR leaf analyses showed that the artificially induced pHapo transient led to an increase in the concentrations of the stomata-regulating plant hormone abscisic acid (ABA) and in transcripts of the key ABA-synthesizing gene ZmVp14 in the leaf. Since stomatal aperture and stomatal conductance decreased according to pHapo, we conclude that the pHapo transient alone initiates stomatal closure. Therefore, the functionality does not depend on interactions with other compounds induced by chloride stress. Overall, our data indicate that the pH of the leaf apoplast links chloride salinity with the control of stomatal aperture via effects exerted on the transcription of ABA.
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Affiliation(s)
- Christoph-Martin Geilfus
- Division of Controlled Environment Horticulture, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg, Berlin, Germany
| | - Xudong Zhang
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Axel Mithöfer
- Max Planck Institute for Chemical Ecology, Research Group Plant Defense Physiology, Hans-Knöll-Straße, Jena, Germany
| | - Lisa Burgel
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Gyöngyi Bárdos
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
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Meyer P, Förster N, Huyskens‐Keil S, Ulrichs C, Geilfus C. Phenolic compound abundance in Pak choi leaves is controlled by salinity and dependent on pH of the leaf apoplast. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2021; 2:36-44. [PMID: 37283845 PMCID: PMC10168030 DOI: 10.1002/pei3.10039] [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: 10/09/2020] [Revised: 01/09/2021] [Accepted: 01/17/2021] [Indexed: 06/08/2023]
Abstract
Onset of salinity induces the pH of the leaf apoplast of Pak choi transiently to increase over a period of 2 to 3 hr. This pH event causes protein abundances in leaves to increase. Among them are enzymes that are key for the phenylpropanoid pathway. To answer the questions whether this short-term salt stress also influences contents of the underlying phenylpropanoids and for clarifying as to whether the apoplastic pH transient plays a role for such a putative effect, Pak choi plants were treated with 37.5 mM CaCl2 against a non-stressed control. A third experimental group, where the leaf apoplast of plants treated with 37.5 mM CaCl2, was clamped in the acidic range by means of infiltration of 5 mM citric acid/sodium citrate (pH 3.6), enabled validation of pH-dependent effects. Microscopy-based live cell imaging was used to quantify leaf apoplastic pH in planta. Phenolics were quantified shortly after the formation of the leaf apoplastic pH transient by means of HPLC-DAD-ESI-MS. Results showed that different phenolic compounds were modulated at 150 and 200 min after the onset of chloride salinity. A pH-independent reduction in phenolic acid abundance as well as an accumulation of phenolic acid:malate conjugates was quantified after 200 min of salt stress. However, at 150 min after the onset of salt stress, flavonoids were significantly reduced by salinity in a pH-dependent manner. These results provided a strong indication that the pH of the apoplast is a relevant component for the short-term metabolic response to chloride salinity.
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Affiliation(s)
- Philipp Meyer
- Faculty of Life SciencesDivision of Controlled Environment HorticultureHumboldt‐Universität zu BerlinBerlinGermany
| | - Nadja Förster
- Faculty of Life SciencesDivision Urban Plant EcophysiologyHumboldt‐Universität zu BerlinBerlinGermany
| | - Susanne Huyskens‐Keil
- Faculty of Life SciencesDivision Urban Plant EcophysiologyHumboldt‐Universität zu BerlinBerlinGermany
| | - Christian Ulrichs
- Faculty of Life SciencesDivision Urban Plant EcophysiologyHumboldt‐Universität zu BerlinBerlinGermany
| | - Christoph‐Martin Geilfus
- Faculty of Life SciencesDivision of Controlled Environment HorticultureHumboldt‐Universität zu BerlinBerlinGermany
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Ismail A, El-Sharkawy I, Sherif S. Salt Stress Signals on Demand: Cellular Events in the Right Context. Int J Mol Sci 2020; 21:ijms21113918. [PMID: 32486204 PMCID: PMC7313037 DOI: 10.3390/ijms21113918] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 05/21/2020] [Accepted: 05/28/2020] [Indexed: 12/19/2022] Open
Abstract
Plant stress is a real dilemma; it puzzles plant biologists and is a global problem that negatively affects people’s daily lives. Of particular interest is salinity, because it represents one of the major water-related stress types. We aimed to determine the signals that guide the cellular-related events where various adaptation mechanisms cross-talk to cope with salinity-related water stress in plants. In an attempt to unravel these mechanisms and introduce cellular events in the right context, we expansively discussed how salt-related signals are sensed, with particular emphasis on aquaporins, nonselective cation channels (NSCCs), and glycosyl inositol phosphorylceramide (GIPC). We also elaborated on the critical role Ca2+, H+, and ROS in mediating signal transduction pathways associated with the response and tolerance to salt stress. In addition, the fragmentary results from the literature were compiled to develop a harmonized, informational, and contemplative model that is intended to improve our perception of these adaptative mechanisms and set a common platform for plant biologists to identify intriguing research questions in this area.
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Affiliation(s)
- Ahmed Ismail
- Department of Horticulture, Faculty of Agriculture, Damanhour University, P.O. Box 22516, Damanhour, Egypt;
| | - Islam El-Sharkawy
- Florida A&M University, Center for Viticulture and Small Fruit Research. 6361 Mahan Drive, Tallahassee, FL 32308, USA;
| | - Sherif Sherif
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Tech, Winchester, VA 22062, USA
- Correspondence: ; Tel.: +1-540-232-6035
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Dai L, Kobayashi K, Nouchi I, Masutomi Y, Feng Z. Quantifying determinants of ozone detoxification by apoplastic ascorbate in peach (Prunus persica) leaves using a model of ozone transport and reaction. GLOBAL CHANGE BIOLOGY 2020; 26:3147-3162. [PMID: 32090419 DOI: 10.1111/gcb.15049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/10/2020] [Indexed: 05/23/2023]
Abstract
Ascorbate in leaf apoplast (ASCapo ) reacts with ozone (O3 ) and thereby reduces O3 flux reaching plasmalemma (Fpl ). Some studies have shown significant protection of cells from O3 by ASCapo , while others have questioned its efficacy. Hypothesizing that the protection by ASCapo depends on other variables, we quantified determinants of O3 detoxification with a model of O3 transport and reaction in apoplast. The model determines ascorbic acid concentration in apoplast (AAapo ) using measured values of O3 concentration (co ), leaf tissue ascorbic acid concentration (AAleaf ), cell wall thickness (L3 ), apoplastic pH (pHapo ), and stomatal conductance (Gsw ). We compared the measured and model-estimated AAapo in leaves of peach (Prunus persica) grown in open-top chambers under non-filtered air (NF) and elevated (EO3 : NF + 80 ppb) O3 concentrations. The estimated AAapo in individual leaves agreed well with the measured values (R2 = .91). Analyses of the simulation results yielded the following findings: (a) The efficacy of O3 reduction with ASCapo as quantified by fractional reduction (ϕ3 ) of O3 flux at the surface of plasmalemma (Fpl ) was lowered from 70% in NF to 40% in EO3 due to the reduction of L3 . The EO3 reduced AAapo , but the lower Gsw and L3 in EO3 increased AAapo resulting in no significant change in AAapo due to EO3 . ϕ3 can be calculated with measured values of AAapo and L3 , and Fpl can be estimated with the measurement-based ϕ3 . (b) When c0 is increased, Fpl increased curvilinearly with the increase of Fst : nominal O3 flux via stomatal diffusion, exhibiting apparent threshold on Fst . The deviation of Fpl from Fst became greater when L3 , pHapo , and AAleaf were increased. The quantification of ϕ3 and Fpl using leaf traits shall facilitate the understanding of the mechanisms of differential plant sensitivity to O3 and improve quantification of the O3 impacts on plants.
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Affiliation(s)
- Lulu Dai
- Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, China
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Kazuhiko Kobayashi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- College of Agriculture, Ibaraki University, Ami, Japan
| | - Isamu Nouchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Masutomi
- College of Agriculture, Ibaraki University, Ami, Japan
| | - Zhaozhong Feng
- Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, China
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Franzisky BL, Geilfus CM, Kränzlein M, Zhang X, Zörb C. Shoot chloride translocation as a determinant for NaCl tolerance in Vicia faba L. JOURNAL OF PLANT PHYSIOLOGY 2019; 236:23-33. [PMID: 30851648 DOI: 10.1016/j.jplph.2019.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Faba bean (Vicia faba L.) is sensitive to salinity. While toxic effects of sodium (Na+) are well studied, toxicity aspects of chloride (Cl-) and the underlying tolerance mechanisms to Cl- are not well understood. For this reason, shoot Cl- translocation and its effect as potential determinant for tolerance was tested. Diverse V. faba varieties were grown hydroponically and stressed with 100 mM NaCl until necrotic leaf spots appeared. At this point, biomass formation, oxidative damage of membranes as well as Na+, Cl- and potassium concentrations were measured. The V. faba varieties contrasted in the length of the period they could withstand the NaCl stress treatment. More tolerant varieties survived longer without evolving necrosis and were less affected by inhibitory effects on photosynthesis. The concentration of Cl- at the time point of developing leaf necrosis was in the same range irrespective of the variety, while that of Na+ varied. This indicates that Cl- concentrations, and not Na+ concentrations are critical for the formation of salt necrosis in faba bean. Tolerant varieties profited from lower Cl- translocation to leaves. Therefore, photosynthesis was less affected in those varieties with lower Cl-. This mechanism is a new trait of interest for salt tolerance in V. faba.
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Affiliation(s)
- Bastian L Franzisky
- University of Hohenheim, Institute of Crop Science, 340e, Schloss Westflügel, 70593, Stuttgart, Germany
| | - Christoph-Martin Geilfus
- Humboldt-University of Berlin, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Controlled Environment Horticulture, Albrecht-Thaer-Weg 1, 14195, Berlin, Germany
| | - Markus Kränzlein
- University of Hohenheim, Institute of Crop Science, 340e, Schloss Westflügel, 70593, Stuttgart, Germany
| | - Xudong Zhang
- University of Hohenheim, Institute of Crop Science, 340e, Schloss Westflügel, 70593, Stuttgart, Germany
| | - Christian Zörb
- University of Hohenheim, Institute of Crop Science, 340e, Schloss Westflügel, 70593, Stuttgart, Germany.
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10
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Richter JA, Behr JH, Erban A, Kopka J, Zörb C. Ion-dependent metabolic responses of Vicia faba L. to salt stress. PLANT, CELL & ENVIRONMENT 2019; 42:295-309. [PMID: 29940081 DOI: 10.1111/pce.13386] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 06/08/2023]
Abstract
Salt-affected farmlands are increasingly burdened by chlorides, carbonates, and sulfates of sodium, calcium, and magnesium. Intriguingly, the underlying physiological processes are studied almost always under NaCl stress. Two faba bean cultivars were subjected to low- and high-salt treatments of NaCl, Na2 SO4 , and KCl. Assimilation rate and leaf water vapor conductance were reduced to approximately 25-30% without biomass reduction after 7 days salt stress, but this did not cause severe carbon shortage. The equimolar treatments of Na+ , K+ , and Cl- showed comparable accumulation patterns in leaves and roots, except for SO42- which did not accumulate. To gain a detailed understanding of the effects caused by the tested ion combinations, we performed nontargeted gas chromatography-mass spectrometry-based metabolite profiling. Metabolic responses to various salts were in part highly linearly correlated, but only a few metabolite responses were common to all salts and in both cultivars. At high salt concentrations, only myo-inositol, allantoin, and glycerophosphoglycerol were highly significantly increased in roots under all tested conditions. We discovered several metabolic responses that were preferentially associated with the presence of Na+ , K+ , or Cl- . For example, increases of leaf proline and decreases of leaf fumaric acid and malic acid were apparently associated with Cl- accumulation.
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Affiliation(s)
- Julia A Richter
- Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| | - Jan H Behr
- Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| | - Alexander Erban
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Joachim Kopka
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Christian Zörb
- Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
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11
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Geilfus CM. Review on the significance of chlorine for crop yield and quality. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 270:114-122. [PMID: 29576063 DOI: 10.1016/j.plantsci.2018.02.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/29/2017] [Accepted: 02/13/2018] [Indexed: 05/28/2023]
Abstract
The chloride concentration in the plant determines yield and quality formation for two reasons. First, chlorine is a mineral nutrient and deficiencies thereof induce metabolic problems that interfere with growth. However, due to low requirement of most crops, deficiency of chloride hardly appears in the field. Second, excess of chloride, an event that occurs under chloride-salinity, results in severe physiological dysfunctions impairing both quality and yield formation. The chloride ion can effect quality of plant-based products by conferring a salty taste that decreases market appeal of e.g. fruit juices and beverages. However, most of the quality impairments are based on physiological dysfunctions that arise under conditions of chloride-toxicity: Shelf life of persimmon is shortened due to an autocatalytic ethylene production in fruit tissues. High concentrations of chloride in the soil can increase phyto-availability of the heavy metal cadmium, accumulating in wheat grains above dietary intake thresholds. When crops are cultivated on soils that are moderately salinized by chloride, nitrate fertilization might be a strategy to suppress uptake of chloride by means of an antagonistic anion-anion uptake competition. Overall, knowledge about proteins that catalyse chloride-efflux out of the roots or that restrict xylem loading is needed to engineer more resistant crops.
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Affiliation(s)
- Christoph-Martin Geilfus
- 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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12
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Geilfus CM. Chloride: from Nutrient to Toxicant. PLANT & CELL PHYSIOLOGY 2018; 59:877-886. [PMID: 29660029 DOI: 10.1093/pcp/pcy071] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 03/05/2018] [Indexed: 05/25/2023]
Abstract
In salinized soils in which chloride (Cl-) is the dominant salt anion, growth of plants that tolerate only low concentrations of salt (glycophytes) is disturbed by Cl- toxicity. Chlorotic discolorations precede necrotic lesions, causing yield reductions. Little is known about the effects of Cl- toxicity on these dysfunctions. A lack of understanding exists regarding (i) the molecular and physiological mechanisms that lead to Cl--induced damage and (ii) the adaptive aspects of induced tolerance to Cl- salinity. Here, mechanistic explanations for the Cl--induced stress responses are proposed and novel ideas and strategies by which glycophytic plants avoid the excessive accumulation of Cl- are reviewed. New experiments are suggested to test the proposed hypotheses. Cl- salinity constrains global food security and thus we urgently need more research into the causes and consequences of Cl- salinity.
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Affiliation(s)
- Christoph-Martin Geilfus
- Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, D-14195 Berlin, Germany
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13
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Someya D, Arai S, Fujie T, Takeoka S. Extracellular pH imaging of a plant leaf with a polyelectrolyte multilayered nanosheet. RSC Adv 2018; 8:35651-35657. [PMID: 35547891 PMCID: PMC9087818 DOI: 10.1039/c8ra06308g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/07/2018] [Indexed: 01/15/2023] Open
Abstract
We have developed a sheet-like pH imaging sensor based on a flexible and physically adhesive polymer thin film (referred to as a “pH sensing nanosheet”). The pH sensing nanosheet was composed of two films: one is a pH-sensitive layer-by-layer (LbL) film constructed from fluorescein-conjugated poly(acrylic acid) and poly(allylamine hydrochloride) and the other is a pH-insensitive film made from Nile red-embedded poly(d,l-lactic acid). The pH sensing nanosheet enabled the ratiometric imaging of pH changes in a leaf (500 × 500 μm2), namely the apoplastic ion milieu responding to an external NaCl stress. It was successfully mapped out that the alkalization of the leaf apoplast spread from the leaf base to the tip at 20 min after the stimulation and the pH value increased up to approximately pH 6.3 from less than pH 4.5 within 60 min when a 100 mM NaCl aqueous solution was added. The pH sensing nanosheet should be useful for energy metabolic mapping in tissue biology. We have developed a sheet-like pH imaging sensor based on a flexible and physically adhesive polymer thin film (referred to as a “pH sensing nanosheet”).![]()
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Affiliation(s)
- Daichi Someya
- Department of Life Science and Medical Bioscience
- Waseda University
- Tokyo 162-8480
- Japan
| | - Satoshi Arai
- PRIME
- Japan Agency for Medical Research and Development (AMED)
- Tokyo 100-0004
- Japan
- Research Institute for Science and Engineering
| | - Toshinori Fujie
- Waseda Institute for Advanced Study
- Waseda University
- Tokyo 162-8480
- Japan
- Japan Science and Technology Agency
| | - Shinji Takeoka
- Department of Life Science and Medical Bioscience
- Waseda University
- Tokyo 162-8480
- Japan
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14
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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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15
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Geilfus CM, Tenhaken R, Carpentier SC. Transient alkalinization of the leaf apoplast stiffens the cell wall during onset of chloride salinity in corn leaves. J Biol Chem 2017; 292:18800-18813. [PMID: 28972176 DOI: 10.1074/jbc.m117.799866] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/11/2017] [Indexed: 12/13/2022] Open
Abstract
During chloride salinity, the pH of the leaf apoplast (pHapo) transiently alkalizes. There is an ongoing debate about the physiological relevance of these stress-induced pHapo changes. Using proteomic analyses of expanding leaves of corn (Zea mays L.), we show that this transition in pHapo conveys functionality by (i) adjusting protein abundances and (ii) affecting the rheological properties of the cell wall. pHapo was monitored in planta via microscopy-based ratio imaging, and the leaf-proteomic response to the transient leaf apoplastic alkalinization was analyzed via ultra-high performance liquid chromatography-MS. This analysis identified 1459 proteins, of which 44 exhibited increased abundance specifically through the chloride-induced transient rise in pHapo These elevated protein abundances did not directly arise from high tissue concentrations of Cl- or Na+ but were due to changes in the pHapo Most of these proteins functioned in growth-relevant processes and in the synthesis of cell wall-building components such as arabinose. Measurements with a linear-variable differential transducer revealed that the transient alkalinization rigidified (i.e. stiffened) the cell wall during the onset of chloride salinity. A decrease in t-coumaric and t-ferulic acids indicates that the wall stiffening arises from cross-linkage to cell wall polymers. We conclude that the pH of the apoplast represents a dynamic factor that is mechanistically coupled to cellular responses to chloride stress. By hardening the wall, the increased pH abrogates wall loosening required for cell expansion and growth. We conclude that the transient alkalinization of the leaf apoplast is related to salinity-induced growth reduction.
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Affiliation(s)
- Christoph-Martin Geilfus
- From SYBIOMA, Proteomics Core Facility, KU Leuven, O&N II Herestraat 49, bus 901, B-3000 Leuven, Belgium, .,the Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, 14195 Berlin, Germany
| | - Raimund Tenhaken
- the Department of Cell Biology, Division of Plant Physiology, University of Salzburg, Salzburg, Austria, and
| | - Sebastien Christian Carpentier
- From SYBIOMA, Proteomics Core Facility, KU Leuven, O&N II Herestraat 49, bus 901, B-3000 Leuven, Belgium.,the Department of Biosystems, Division of Crop Biotechnics, KU Leuven, Willem de Croylaan 42, Box 2455, B-3001 Leuven, Belgium
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16
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Farooq M, Gogoi N, Hussain M, Barthakur S, Paul S, Bharadwaj N, Migdadi HM, Alghamdi SS, Siddique KHM. Effects, tolerance mechanisms and management of salt stress in grain legumes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 118:199-217. [PMID: 28648997 DOI: 10.1016/j.plaphy.2017.06.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 06/14/2017] [Accepted: 06/15/2017] [Indexed: 05/23/2023]
Abstract
Salt stress is an ever-present threat to crop yields, especially in countries with irrigated agriculture. Efforts to improve salt tolerance in crop plants are vital for sustainable crop production on marginal lands to ensure future food supplies. Grain legumes are a fascinating group of plants due to their high grain protein contents and ability to fix biological nitrogen. However, the accumulation of excessive salts in soil and the use of saline groundwater are threatening legume production worldwide. Salt stress disturbs photosynthesis and hormonal regulation and causes nutritional imbalance, specific ion toxicity and osmotic effects in legumes to reduce grain yield and quality. Understanding the responses of grain legumes to salt stress and the associated tolerance mechanisms, as well as assessing management options, may help in the development of strategies to improve the performance of grain legumes under salt stress. In this manuscript, we discuss the effects, tolerance mechanisms and management of salt stress in grain legumes. The principal inferences of the review are: (i) salt stress reduces seed germination (by up to more than 50%) either by inhibiting water uptake and/or the toxic effect of ions in the embryo, (ii) salt stress reduces growth (by more than 70%), mineral uptake, and yield (by 12-100%) due to ion toxicity and reduced photosynthesis, (iii) apoplastic acidification is a good indicator of salt stress tolerance, (iv) tolerance to salt stress in grain legumes may develop through excretion and/or compartmentalization of toxic ions, increased antioxidant capacity, accumulation of compatible osmolytes, and/or hormonal regulation, (v) seed priming and nutrient management may improve salt tolerance in grain legumes, (vi) plant growth promoting rhizobacteria and arbuscular mycorrhizal fungi may help to improve salt tolerance due to better plant nutrient availability, and (vii) the integration of screening, innovative breeding, and the development of transgenics and crop management strategies may enhance salt tolerance and yield in grain legumes on salt-affected soils.
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Affiliation(s)
- Muhammad Farooq
- Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan; The UWA Institute of Agriculture and School of Agriculture & Environment, The University of Western Australia, Perth, WA 6001, Australia; College of Food and Agricultural Sciences, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Nirmali Gogoi
- Department of Environmental Science, Tezpur University, Tezpur 784028, Assam, India
| | - Mubshar Hussain
- Department of Agronomy, Bahauddin Zakariya University Multan, Pakistan
| | - Sharmistha Barthakur
- National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Sreyashi Paul
- Department of Environmental Science, Tezpur University, Tezpur 784028, Assam, India
| | - Nandita Bharadwaj
- Department of Environmental Science, Tezpur University, Tezpur 784028, Assam, India
| | - Hussein M Migdadi
- College of Food and Agricultural Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Salem S Alghamdi
- College of Food and Agricultural Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture and School of Agriculture & Environment, The University of Western Australia, Perth, WA 6001, Australia
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17
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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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18
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Raven JA. Chloride: essential micronutrient and multifunctional beneficial ion. JOURNAL OF EXPERIMENTAL BOTANY 2017; 38:359-367. [PMID: 28040799 DOI: 10.1093/jxb/erw421] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Cl− is an essential micronutrient for oxygenic photolithotrophs. About half of global primary productivity is carried out by oxygenic photolithotrophs exposed to saline waters with Cl− concentrations orders of magnitude higher than that needed to satisfy the micronutrient requirement. The other half of primary productivity involves terrestrial and freshwater glycophytes sometimes in environments containing significantly more Cl− than is needed for the micronutrient requirement, but less than the toxic Cl– concentration for glycophytes. Intracellular Cl− acts in regulation of cell turgor and volume, including that of stomatal and pulvinar nastic movements, is a major ion in streptophyte and ulvophycean action potentials, and is involved in ion currents flowing around apices of pollen tubes and Acetabularia cells. More work is needed on the essentiality of Cl− in these processes, as well as the recent finding that Cl− at 1–5 mol m−3 increases water use efficiency of growth and leaf area in Nicotiana tabacum.
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Affiliation(s)
- John A Raven
- Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, UK
- School of Plant Biology, University of Western Australia MO84, Stirling Highway. Crawley, WA, Australia
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19
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McLachlan DH, Lan J, Geilfus CM, Dodd AN, Larson T, Baker A, Hõrak H, Kollist H, He Z, Graham I, Mickelbart MV, Hetherington AM. The Breakdown of Stored Triacylglycerols Is Required during Light-Induced Stomatal Opening. Curr Biol 2016; 26:707-12. [PMID: 26898465 PMCID: PMC4791430 DOI: 10.1016/j.cub.2016.01.019] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/09/2015] [Accepted: 01/07/2016] [Indexed: 12/22/2022]
Abstract
Stomata regulate the uptake of CO2 and the loss of water vapor [1] and contribute to the control of water-use efficiency [2] in plants. Although the guard-cell-signaling pathway coupling blue light perception to ion channel activity is relatively well understood [3], we know less about the sources of ATP required to drive K+ uptake [3, 4, 5, 6]. Here, we show that triacylglycerols (TAGs), present in Arabidopsis guard cells as lipid droplets (LDs), are involved in light-induced stomatal opening. Illumination induces reductions in LD abundance, and this involves the PHOT1 and PHOT2 blue light receptors [3]. Light also induces decreases in specific TAG molecular species. We hypothesized that TAG-derived fatty acids are metabolized by peroxisomal β-oxidation to produce ATP required for stomatal opening. In silico analysis revealed that guard cells express all the genes required for β-oxidation, and we showed that light-induced stomatal opening is delayed in three TAG catabolism mutants (sdp1, pxa1, and cgi-58) and in stomata treated with a TAG breakdown inhibitor. We reasoned that, if ATP supply was delaying light-induced stomatal opening, then the activity of the plasma membrane H+-ATPase should be reduced at this time. Monitoring changes in apoplastic pH in the mutants showed that this was the case. Together, our results reveal a new role for TAGs in vegetative tissue and show that PHOT1 and PHOT2 are involved in reductions in LD abundance. Reductions in LD abundance in guard cells of the lycophyte Selaginella suggest that TAG breakdown may represent an evolutionarily conserved mechanism in light-induced stomatal opening. Guard cells break down triacylglycerols to supply ATP for use in stomatal opening Light-induced stomatal opening is delayed in triacylglycerol catabolism mutants PHOT blue light receptors are involved in reductions in lipid droplet (LD) abundance Light-induced reductions in LD abundance occur in Selaginella guard cells
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Affiliation(s)
- Deirdre H McLachlan
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Jue Lan
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Christoph-Martin Geilfus
- Institut fur Pflanzenernährung und Bodenkunde, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald- Straße 2, 24118 Kiel, Germany
| | - Antony N Dodd
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Tony Larson
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Alison Baker
- Centre for Plant Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Hanna Hõrak
- Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| | - Hannes Kollist
- Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| | - Zhesi He
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Ian Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Michael V Mickelbart
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK; Department of Botany and Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
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20
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Geilfus CM, Mithöfer A, Ludwig-Müller J, Zörb C, Muehling KH. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba. THE NEW PHYTOLOGIST 2015; 208:803-16. [PMID: 26096890 DOI: 10.1111/nph.13507] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/10/2015] [Indexed: 05/08/2023]
Abstract
Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity.
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Affiliation(s)
- Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University, Hermann-Rodewald-Str. 2, D-24118, Kiel, Germany
| | - Axel Mithöfer
- Department Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745, Jena, Germany
| | - Jutta Ludwig-Müller
- Institut für Botanik, Technische Universität Dresden, Zellescher Weg 20b, D-01062, Dresden, Germany
| | - Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof West, 118, D-70593, Stuttgart, Germany
| | - Karl H Muehling
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University, Hermann-Rodewald-Str. 2, D-24118, Kiel, Germany
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Geilfus CM, Niehaus K, Gödde V, Hasler M, Zörb C, Gorzolka K, Jezek M, Senbayram M, Ludwig-Müller J, Mühling KH. Fast responses of metabolites in Vicia faba L. to moderate NaCl stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 92:19-29. [PMID: 25900421 DOI: 10.1016/j.plaphy.2015.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/08/2015] [Accepted: 04/08/2015] [Indexed: 06/04/2023]
Abstract
Salt stress impairs global agricultural crop production by reducing vegetative growth and yield. Despite this importance, a number of gaps exist in our knowledge about very early metabolic responses that ensue minutes after plants experience salt stress. Surprisingly, this early phase remains almost as a black box. Therefore, systematic studies focussing on very early plant physiological responses to salt stress (in this case NaCl) may enhance our understanding on strategies to develop crop plants with a better performance under saline conditions. In the present study, hydroponically grown Vicia faba L. plants were exposed to 90 min of NaCl stress, whereby every 15 min samples were taken for analyzing short-term physiologic responses. Gas chromatography-mass spectrometry-based metabolite profiles were analysed by calculating a principal component analysis followed by multiple contrast tests. Follow-up experiments were run to analyze downstream effects of the metabolic changes on the physiological level. The novelty of this study is the demonstration of complex stress-induced metabolic changes at the very beginning of a moderate salt stress in V. faba, information that are very scant for this early stage. This study reports for the first that the proline analogue trans-4-hydroxy-L-proline, known to inhibit cell elongation, was increasingly synthesized after NaCl-stress initiation. Leaf metabolites associated with the generation or scavenging of reactive oxygen species (ROS) were affected in leaves that showed a synchronized increase in ROS formation. A reduced glutamine synthetase activity indicated that disturbances in the nitrogen assimilation occur earlier than it was previously thought under salt stress.
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Affiliation(s)
- Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University Kiel, Hermann-Rodewald Str. 2, D-24118 Kiel, Germany.
| | - Karsten Niehaus
- Department of Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Postfach 100131, D-33501 Bielefeld, Germany
| | - Victoria Gödde
- Department of Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Postfach 100131, D-33501 Bielefeld, Germany
| | - Mario Hasler
- Lehrfach Variationsstatistik, Christian Albrechts University Kiel, Hermann-Rodewald Str. 9, D-24118 Kiel, Germany
| | - Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof West, 118, D-70593 Stuttgart, Germany
| | - Karin Gorzolka
- Department of Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Postfach 100131, D-33501 Bielefeld, Germany
| | - Mareike Jezek
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University Kiel, Hermann-Rodewald Str. 2, D-24118 Kiel, Germany
| | - Mehmet Senbayram
- Institute of Applied Plant Nutrition, Plant Nutrition, Georg-August-University Göttingen, Carl-Sprengel-Weg 1, D-37075 Göttingen, Germany
| | - Jutta Ludwig-Müller
- Institute of Botany, Technische Universität Dresden, Zellescher Weg 20b, D-01062 Dresden, Germany
| | - Karl H Mühling
- Institute of Plant Nutrition and Soil Science, Christian Albrechts University Kiel, Hermann-Rodewald Str. 2, D-24118 Kiel, Germany
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22
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Zörb C, Mühling KH, Kutschera U, Geilfus CM. Salinity stiffens the epidermal cell walls of salt-stressed maize leaves: is the epidermis growth-restricting? PLoS One 2015; 10:e0118406. [PMID: 25760715 PMCID: PMC4356557 DOI: 10.1371/journal.pone.0118406] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/15/2015] [Indexed: 01/19/2023] Open
Abstract
As a result of salt (NaCl)-stress, sensitive varieties of maize (Zea mays L.) respond with a strong inhibition of organ growth. The reduction of leaf elongation investigated here has several causes, including a modification of the mechanical properties of the cell wall. Among the various tissues that form the leaf, the epidermis plays a special role in controlling organ growth, because it is thought to form a rigid outer leaf coat that can restrict elongation by interacting with the inner cell layers. This study was designed to determine whether growth-related changes in the leaf epidermis and its cell wall correspond to the overall reduction in cell expansion of maize leaves during an osmotic stress-phase induced by salt treatment. Two different maize varieties contrasting in their degree of salt resistance (i.e., the hybrids Lector vs. SR03) were compared in order to identify physiological features contributing to resistance towards salinity. Wall loosening-related parameters, such as the capacity of the epidermal cell wall to expand, β-expansin abundance and apoplastic pH values, were analysed. Our data demonstrate that, in the salt-tolerant maize hybrid which maintained leaf growth under salinity, the epidermal cell wall was more extensible under salt stress. This was associated with a shift of the epidermal apoplastic pH into a range more favourable for acid growth. The more sensitive hybrid that displayed a pronounced leaf growth-reduction was shown to have stiffer epidermal cell walls under stress. This may be attributable to the reduced abundance of cell wall-loosening β-expansin proteins following a high salinity-treatment in the nutrient solution (100 mM NaCl, 8 days). This study clearly documents that salt stress impairs epidermal wall-loosening in growth-reduced maize leaves.
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Affiliation(s)
- Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University of Hohenheim, Stuttgart, Germany
| | - Karl H. Mühling
- Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
| | | | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
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Geilfus CM, Ober D, Eichacker LA, Mühling KH, Zörb C. Down-regulation of ZmEXPB6 (Zea mays β-expansin 6) protein is correlated with salt-mediated growth reduction in the leaves of Z. mays L. J Biol Chem 2015; 290:11235-45. [PMID: 25750129 DOI: 10.1074/jbc.m114.619718] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Indexed: 11/06/2022] Open
Abstract
The salt-sensitive crop Zea mays L. shows a rapid leaf growth reduction upon NaCl stress. There is increasing evidence that salinity impairs the ability of the cell walls to expand, ultimately inhibiting growth. Wall-loosening is a prerequisite for cell wall expansion, a process that is under the control of cell wall-located expansin proteins. In this study the abundance of those proteins was analyzed against salt stress using gel-based two-dimensional proteomics and two-dimensional Western blotting. Results show that ZmEXPB6 (Z. mays β-expansin 6) protein is lacking in growth-inhibited leaves of salt-stressed maize. Of note, the exogenous application of heterologously expressed and metal-chelate-affinity chromatography-purified ZmEXPB6 on growth-reduced leaves that lack native ZmEXPB6 under NaCl stress partially restored leaf growth. In vitro assays on frozen-thawed leaf sections revealed that recombinant ZmEXPB6 acts on the capacity of the walls to extend. Our results identify expansins as a factor that partially restores leaf growth of maize in saline environments.
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Affiliation(s)
- Christoph-Martin Geilfus
- From the Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University, Hermann-Rodewald-Strasse 2, 24118 Kiel, Germany,
| | - Dietrich Ober
- Botanical Institute and Botanical Gardens, Biochemical Ecology and Molecular Evolution, Christian-Albrechts-University, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Lutz A Eichacker
- Universitetet i Stavanger, Center for Organelle Research (CORE), Richard Johnsensgt. 4, N-4021, Norway, and
| | - Karl Hermann Mühling
- From the Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University, Hermann-Rodewald-Strasse 2, 24118 Kiel, Germany
| | - Christian Zörb
- From the Institute of Plant Nutrition and Soil Science, Christian-Albrechts-University, Hermann-Rodewald-Strasse 2, 24118 Kiel, Germany, Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof West, 118, 70593 Stuttgart, Germany
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Geilfus CM, Mühling KH, Kaiser H, Plieth C. Bacterially produced Pt-GFP as ratiometric dual-excitation sensor for in planta mapping of leaf apoplastic pH in intact Avena sativa and Vicia faba. PLANT METHODS 2014; 10:31. [PMID: 25313311 PMCID: PMC4194361 DOI: 10.1186/1746-4811-10-31] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/20/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND Ratiometric analysis with H(+)-sensitive fluorescent sensors is a suitable approach for monitoring apoplastic pH dynamics. For the acidic range, the acidotropic dual-excitation dye Oregon Green 488 is an excellent pH sensor. Long lasting (hours) recordings of apoplastic pH in the near neutral range, however, are more problematic because suitable pH indicators that combine a good pH responsiveness at a near neutral pH with a high photostability are lacking. The fluorescent pH reporter protein from Ptilosarcus gurneyi (Pt-GFP) comprises both properties. But, as a genetically encoded indicator and expressed by the plant itself, it can be used almost exclusively in readily transformed plants. In this study we present a novel approach and use purified recombinant indicators for measuring ion concentrations in the apoplast of crop plants such as Vicia faba L. and Avena sativa L. RESULTS Pt-GFP was purified using a bacterial expression system and subsequently loaded through stomata into the leaf apoplast of intact plants. Imaging verified the apoplastic localization of Pt-GFP and excluded its presence in the symplast. The pH-dependent emission signal stood out clearly from the background. PtGFP is highly photostable, allowing ratiometric measurements over hours. By using this approach, a chloride-induced alkalinizations of the apoplast was demonstrated for the first in oat. CONCLUSIONS Pt-GFP appears to be an excellent sensor for the quantification of leaf apoplastic pH in the neutral range. The presented approach encourages to also use other genetically encoded biosensors for spatiotemporal mapping of apoplastic ion dynamics.
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Affiliation(s)
- Christoph-Martin Geilfus
- />Institute of Plant Nutrition and Soil Science, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany
| | - Karl H Mühling
- />Institute of Plant Nutrition and Soil Science, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany
| | - Hartmut Kaiser
- />Botanisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 3-9, 24118 Kiel, Germany
| | - Christoph Plieth
- />Zentrum für Biochemie und Molekularbiologie, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 3-9, 24118 Kiel, Germany
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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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Ismail A, Seo M, Takebayashi Y, Kamiya Y, Eiche E, Nick P. Salt adaptation requires efficient fine-tuning of jasmonate signalling. PROTOPLASMA 2014; 251:881-98. [PMID: 24297515 DOI: 10.1007/s00709-013-0591-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 11/20/2013] [Indexed: 05/21/2023]
Abstract
Understanding the mechanism by which plants sense, signal and respond to salinity stress is of great interest to plant biologists. In stress signalling, often the same molecules are involved in both damage-related and adaptive events. To dissect this complexity, we compared the salinity responses of two grapevine cell lines differing in their salinity tolerance. We followed rapid changes in the cellular content of sodium and calcium, apoplastic alkalinisation and slower responses in the levels of jasmonic acid, its active isoleucine conjugate and abscisic acid, as well as of stilbenes. Differences in timing and sensitivity to either the lanthanoid Gd or exogenous calcium provide evidence for an adaptive role of early sodium uptake through non-selective cation channels acting upstream of Ca(2+) and H(+) fluxes. We find a correlation of salt sensitivity with unconstrained jasmonate (JA) signalling, whereas salt adaptation correlates with tight control of jasmonic acid and its isoleucine conjugate, accompanied by accumulation of abscisic acid and suppression of stilbenes that trigger defence-related cell death. The data are discussed by a model where efficient fine-tuning of JA signalling determines whether cells will progress towards adaptation or programme cell death.
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Affiliation(s)
- Ahmed Ismail
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany,
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Ismail A, Takeda S, Nick P. Life and death under salt stress: same players, different timing? JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2963-79. [PMID: 24755280 DOI: 10.1093/jxb/eru159] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Salinity does not only stress plants but also challenges human life and the economy by posing severe constraints upon agriculture. To understand salt adaptation strategies of plants, it is central to extend agricultural production to salt-affected soils. Despite high impact and intensive research, it has been difficult to dissect the plant responses to salt stress and to define the decisive key factors for the outcome of salinity signalling. To connect the rapidly accumulating data from different systems, treatments, and organization levels (whole-plant, cellular, and molecular), and to identify the appropriate correlations among them, a clear conceptual framework is required. Similar to other stress responses, the molecular nature of the signals evoked after the onset of salt stress seems to be general, as with that observed in response to many other stimuli, and should not be considered to confer specificity per se. The focus of the current review is therefore on the temporal patterns of signals conveyed by molecules such as Ca(2+), H(+), reactive oxygen species, abscisic acid, and jasmonate. We propose that the outcome of the salinity response (adaptation versus cell death) depends on the timing with which these signals appear and disappear. In this context, the often-neglected non-selective cation channels are relevant. We also propose that constraining a given signal is as important as its induction, as it is the temporal competence of signalling (signal on demand) that confers specificity.
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Affiliation(s)
- Ahmed Ismail
- Department of Horticulture, Faculty of Agriculture, Damanhour University, Damanhour, Egypt
| | - Shin Takeda
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology (KIT), Germany
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Geilfus CM, Mühling KH. Microscopic and macroscopic monitoring of adaxial-abaxial pH gradients in the leaf apoplast of Vicia faba L. as primed by NaCl stress at the roots. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 223:109-115. [PMID: 24767120 DOI: 10.1016/j.plantsci.2014.03.012] [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: 01/07/2014] [Revised: 03/12/2014] [Accepted: 03/16/2014] [Indexed: 06/03/2023]
Abstract
The pH is a basic chemical requirement in cellular and apoplastic compartments that influences various physiological processes in plants. Apoplastic pH shifts can modulate the apoplastic and symplastic distribution of plant hormones or influence proton motive force-driven uptake processes over the plasma-membrane. Changing environments are known to effect on the apoplastic H(+)-concentration in leaves and roots. The onset of NaCl-stress at the roots for instance primes a chloride-specific systemic alkalinization of the leaf apoplast. By means of microscopy- and macroscopy-based in planta ratio-imaging we surprisingly found that large adaxial-abaxial pH gradients were established throughout the leaf apoplast during the formation of the NaCl-induced alkalinization. Moreover, the root system is necessary to ensure the transient nature of the leaf apoplastic alkalinization.
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Affiliation(s)
- Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
| | - Karl-Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
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