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Roy BC, Mukherjee A. Computational analysis of the glutamate receptor gene family of Arabidopsis thaliana. J Biomol Struct Dyn 2016; 35:2454-2474. [PMID: 27632363 DOI: 10.1080/07391102.2016.1222968] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Bidhan Chandra Roy
- Department of Botany, Dinabandhu Mahavidyalaya, North 24 Parganas, Bongaon, West Bengal 743235, India
| | - Ashutosh Mukherjee
- Department of Botany, Vivekananda College, 269, Diamond Harbour Road, Thakurpukur, Kolkata, West Bengal 700063, India
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52
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Jha SK, Sharma M, Pandey GK. Role of Cyclic Nucleotide Gated Channels in Stress Management in Plants. Curr Genomics 2016; 17:315-29. [PMID: 27499681 PMCID: PMC4955031 DOI: 10.2174/1389202917666160331202125] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022] Open
Abstract
Tolerance of plants to a number of biotic and abiotic stresses such as pathogen and herbivore attack, drought, salinity, cold and nutritional limitations is ensued by complex multimodule signaling pathways. The outcome of this complex signaling pathways results in adaptive responses by restoring the cellular homeostasis and thus promoting survival. Functions of many plant cation transporter and channel protein families such as glutamate receptor homologs (GLRs), cyclic nucleotide-gated ion channel (CNGC) have been implicated in providing biotic and abiotic stress tolerance. Ion homeostasis regulated by several transporters and channels is one of the crucial parameters for the optimal growth, development and survival of all living organisms. The CNGC family members are known to be involved in the uptake of cations such as Na(+), K(+) and Ca(2+) and regulate plant growth and development. Detail functional genomics approaches have given an emerging picture of CNGCs wherein these protein are believed to play crucial role in pathways related to cellular ion homeostasis, development and as a 'guard' in defense against biotic and abiotic challenges. Here, we discuss the current knowledge of role of CNGCs in mediating stress management and how they aid plants in survival under adverse conditions.
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Affiliation(s)
- Saroj K. Jha
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Manisha Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Girdhar K. Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
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53
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Chakraborty K, Bose J, Shabala L, Shabala S. Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4611-25. [PMID: 27340231 PMCID: PMC4973732 DOI: 10.1093/jxb/erw236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus, B. juncea, and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na(+) extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na(+)/H(+) exchangers; (ii) better root K(+) retention ability resulting from stress-inducible activation of H(+)-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K(+)-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1, HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species.
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Affiliation(s)
- Koushik Chakraborty
- Department of Plant Physiology, ICAR-Directorate of Groundnut Research, Junagadh, Gujarat-362 001, India School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Jayakumar Bose
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Lana Shabala
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Sergey Shabala
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
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Ben Hamed-Laouti I, Arbelet-Bonnin D, De Bont L, Biligui B, Gakière B, Abdelly C, Ben Hamed K, Bouteau F. Comparison of NaCl-induced programmed cell death in the obligate halophyte Cakile maritima and the glycophyte Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 247:49-59. [PMID: 27095399 DOI: 10.1016/j.plantsci.2016.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Salinity represents one of the most important constraints that adversely affect plants growth and productivity. In this study, we aimed at determining possible differences between salt tolerant and salt sensitive species in early salt stress response. To this purpose, we subjected suspension-cultured cells from the halophyte Cakile maritima and the glycophyte Arabidopsis thaliana, two Brassicaceae, to salt stress and compared their behavior. In both species we could observe a time and dose dependent programmed cell death requiring an active metabolism, a dysfunction of mitochondria and caspase-like activation although C. maritima cells appeared less sensitive than A. thaliana cells. This capacity to mitigate salt stress could be due to a higher ascorbate pool that could allow C. maritima reducing the oxidative stress generated in response to NaCl. It further appeared that a higher number of C. maritima cultured cells when compared to A. thaliana could efficiently manage the Na(+) accumulation into the cytoplasm through non selective cation channels allowing also reducing the ROS generation and the subsequent cell death.
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Affiliation(s)
- Ibtissem Ben Hamed-Laouti
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France; Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj Cedria, University of Carthage-Tunis, BP 901, 2050 Hammam Lif, Tunisia
| | - Delphine Arbelet-Bonnin
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France
| | - Linda De Bont
- Institute of Plant Sciences-Paris-Saclay (UMR 9213) Bât. 630, 91405 Orsay, France
| | - Bernadette Biligui
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France
| | - Bertrand Gakière
- Institute of Plant Sciences-Paris-Saclay (UMR 9213) Bât. 630, 91405 Orsay, France
| | - Chedly Abdelly
- Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj Cedria, University of Carthage-Tunis, BP 901, 2050 Hammam Lif, Tunisia
| | - Karim Ben Hamed
- Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj Cedria, University of Carthage-Tunis, BP 901, 2050 Hammam Lif, Tunisia
| | - François Bouteau
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France.
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55
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Voss LJ, Hedrich R, Roelfsema MRG. Current Injection Provokes Rapid Expansion of the Guard Cell Cytosolic Volume and Triggers Ca(2+) Signals. MOLECULAR PLANT 2016; 9:471-480. [PMID: 26902185 DOI: 10.1016/j.molp.2016.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 01/07/2016] [Accepted: 02/14/2016] [Indexed: 06/05/2023]
Abstract
High-resolution microscopy opens the door for detailed single-cell studies with fluorescent reporter dyes and proteins. We used a confocal spinning disc microscope to monitor fluorescent dyes and the fluorescent protein Venus in tobacco and Arabidopsis guard cells. Multi-barreled microelectrodes were used to inject dyes and apply voltage pulses, which provoke transient rises in the cytosolic Ca(2+) level. Voltage pulses also caused changes in the distribution of Lucifer Yellow and Venus, which pointed to a reversible increase of guard cell cytosolic volume. The dynamic cytosolic volume changes turned out to be provoked by current injection of ions. A reduction of the clamp current, by blocking K(+) uptake channels with Cs(+), strongly suppressed the cytosolic volume changes. Cs(+) not only inhibited the expansion of the cytosol, but also inhibited hyperpolarization-induced elevations of the cytosolic Ca(2+) concentration. A complete loss of voltage-induced Ca(2+) signals occurred when Ca(2+)-permeable plasma membrane channels were simultaneously blocked with La(3+). This shows that two mechanisms cause hyperpolarization-induced elevation of the cytosolic Ca(2+)-concentration: (i) activation of voltage-dependent Ca(2+)-permeable channels, (ii) osmotically induced expansion of the cytosol, which leads to a release of Ca(2+) from intracellular stores.
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Affiliation(s)
- Lena J Voss
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Rainer Hedrich
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - M Rob G Roelfsema
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany.
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56
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Gupta N, Ram H, Kumar B. Mechanism of Zinc absorption in plants: uptake, transport, translocation and accumulation. REVIEWS IN ENVIRONMENTAL SCIENCE AND BIO/TECHNOLOGY 2016. [PMID: 0 DOI: 10.1007/s11157-016-9390-1] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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57
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Sosan A, Svistunenko D, Straltsova D, Tsiurkina K, Smolich I, Lawson T, Subramaniam S, Golovko V, Anderson D, Sokolik A, Colbeck I, Demidchik V. Engineered silver nanoparticles are sensed at the plasma membrane and dramatically modify the physiology of Arabidopsis thaliana plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:245-57. [PMID: 26676841 DOI: 10.1111/tpj.13105] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 11/15/2015] [Accepted: 11/30/2015] [Indexed: 05/23/2023]
Abstract
Silver nanoparticles (Ag NPs) are the world's most important nanomaterial and nanotoxicant. The aim of this study was to determine the early stages of interactions between Ag NPs and plant cells, and to investigate their physiological roles. We have shown that the addition of Ag NPs to cultivation medium, at levels above 300 mg L(-1) , inhibited Arabidopsis thaliana root elongation and leaf expansion. This also resulted in decreased photosynthetic efficiency and the extreme accumulation of Ag in tissues. Acute application of Ag NPs induced a transient elevation of [Ca(2+) ]cyt and the accumulation of reactive oxygen species (ROS; partially generated by NADPH oxidase). Whole-cell patch-clamp measurements on root cell protoplasts demonstrated that Ag NPs slightly inhibited plasma membrane K(+) efflux and Ca(2+) influx currents, or caused membrane breakdown; however, in excised outside-out patches, Ag NPs activated Gd(3+) -sensitive Ca(2+) influx channels with unitary conductance of approximately 56 pS. Bulk particles did not modify the plasma membrane currents. Tests with electron paramagnetic resonance spectroscopy showed that Ag NPs were not able to catalyse hydroxyl radical generation, but that they directly oxidized the major plant antioxidant, l-ascorbic acid. Overall, the data presented shed light on mechanisms of the impact of nanosilver on plant cells, and show that these include the induction of classical stress signalling reactions (mediated by [Ca(2+) ]cyt and ROS) and a specific effect on the plasma membrane conductance and the reduced ascorbate.
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Affiliation(s)
- Arifa Sosan
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | - Dimitri Svistunenko
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | - Darya Straltsova
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus
| | - Katsiaryna Tsiurkina
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus
| | - Igor Smolich
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus
| | - Tracy Lawson
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | - Sunitha Subramaniam
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | - Vladimir Golovko
- Department of Chemistry, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, 8041, New Zealand
| | - David Anderson
- Department of Chemistry, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, 8041, New Zealand
| | - Anatoliy Sokolik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus
| | - Ian Colbeck
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | - Vadim Demidchik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus
- Russian Academy of Sciences, Komarov Botanical Institute, 2 Professora Popova Street, 197376, St.-Petersburg, Russia
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58
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Yi C, Yao K, Cai S, Li H, Zhou J, Xia X, Shi K, Yu J, Foyer CH, Zhou Y. High atmospheric carbon dioxide-dependent alleviation of salt stress is linked to RESPIRATORY BURST OXIDASE 1 (RBOH1)-dependent H2O2 production in tomato (Solanum lycopersicum). JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:7391-404. [PMID: 26417022 PMCID: PMC4765801 DOI: 10.1093/jxb/erv435] [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] [Indexed: 05/03/2023]
Abstract
Plants acclimate rapidly to stressful environmental conditions. Increasing atmospheric CO2 levels are predicted to influence tolerance to stresses such as soil salinity but the mechanisms are poorly understood. To resolve this issue, tomato (Solanum lycopersicum) plants were grown under ambient (380 μmol mol(-1)) or high (760 μmol mol(-1)) CO2 in the absence or presence of sodium chloride (100mM). The higher atmospheric CO2 level induced the expression of RESPIRATORY BURST OXIDASE 1 (SlRBOH1) and enhanced H2O2 accumulation in the vascular cells of roots, stems, leaf petioles, and the leaf apoplast. Plants grown with higher CO2 levels showed improved salt tolerance, together with decreased leaf transpiration rates and lower sodium concentrations in the xylem sap, vascular tissues, and leaves. Silencing SlRBOH1 abolished high CO2 -induced salt tolerance and increased leaf transpiration rates, as well as enhancing Na(+) accumulation in the plants. The higher atmospheric CO2 level increased the abundance of a subset of transcripts involved in Na(+) homeostasis in the controls but not in the SlRBOH1-silenced plants. It is concluded that high atmospheric CO2 concentrations increase salt stress tolerance in an apoplastic H2O2 dependent manner, by suppressing transpiration and hence Na(+) delivery from the roots to the shoots, leading to decreased leaf Na(+) accumulation.
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Affiliation(s)
- Changyu Yi
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Kaiqian Yao
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Shuyu Cai
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Huizi Li
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Jie Zhou
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Xiaojian Xia
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Kai Shi
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Jingquan Yu
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
| | - Christine Helen Foyer
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Yanhong Zhou
- Department of Horticulture, Zijingang Campus, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China
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59
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Volkov V. Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes. FRONTIERS IN PLANT SCIENCE 2015; 6:873. [PMID: 26579140 PMCID: PMC4621421 DOI: 10.3389/fpls.2015.00873] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/01/2015] [Indexed: 05/18/2023]
Abstract
Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowledge about mechanisms of ion transport and individual genes of ion transport proteins. Initially, the Review describes methods to measure ion fluxes, the independent set of techniques ensures robust and reliable basement for quantitative approach. The Review briefly summarizes current data concerning Na(+) and K(+) concentrations in cells, refers to primary thermodynamics of ion transport and gives special attention to individual ion channels and transporters. Simplified scheme of a plant cell with known transport systems at the plasma membrane and tonoplast helps to imagine the complexity of ion transport and allows choosing specific transporters for modulating ion transport. The complexity is enhanced by the influence of cell size and cell wall on ion transport. Special attention is given to ion transporters and to potassium and sodium transport by HKT, HAK, NHX, and SOS1 proteins. Comparison between non-selective cation channels and ion transporters reveals potential importance of ion transporters and the balance between the two pathways of ion transport. Further on the Review describes in detail several successful attempts to overexpress or knockout ion transporters for changing salinity tolerance. Future perspectives are questioned with more attention given to promising candidate ion channels and transporters for altered expression. Potential direction of increasing salinity tolerance by modifying ion channels and transporters using single point mutations is discussed and questioned. An alternative approach from synthetic biology is to create new regulation networks using novel transport proteins with desired properties for transforming agricultural crops. The approach had not been widely used earlier; it leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis. Summarizing, several potential ways are aimed at required increase in salinity tolerance of plants of interest.
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Affiliation(s)
- Vadim Volkov
- Faculty of Life Sciences and Computing, London Metropolitan UniversityLondon, UK
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60
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Kolupaev YE, Karpets YV, Dmitriev AP. Signal mediators in plants in response to abiotic stress: Calcium, reactive oxygen and nitrogen species. CYTOL GENET+ 2015. [DOI: 10.3103/s0095452715050047] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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61
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Keinath NF, Waadt R, Brugman R, Schroeder JI, Grossmann G, Schumacher K, Krebs M. Live Cell Imaging with R-GECO1 Sheds Light on flg22- and Chitin-Induced Transient [Ca(2+)]cyt Patterns in Arabidopsis. MOLECULAR PLANT 2015; 8:1188-200. [PMID: 26002145 PMCID: PMC5134422 DOI: 10.1016/j.molp.2015.05.006] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 05/03/2015] [Accepted: 05/05/2015] [Indexed: 05/17/2023]
Abstract
Intracellular Ca(2+) transients are an integral part of the signaling cascade during pathogen-associated molecular pattern (PAMP)-triggered immunity in plants. Yet, our knowledge about the spatial distribution of PAMP-induced Ca(2+) signals is limited. Investigation of cell- and tissue-specific properties of Ca(2+)-dependent signaling processes requires versatile Ca(2+) reporters that are able to extract spatial information from cellular and subcellular structures, as well as from whole tissues over time periods from seconds to hours. Fluorescence-based reporters cover both a broad spatial and temporal range, which makes them ideally suited to study Ca(2+) signaling in living cells. In this study, we compared two fluorescence-based Ca(2+) sensors: the Förster resonance energy transfer (FRET)-based reporter yellow cameleon NES-YC3.6 and the intensity-based sensor R-GECO1. We demonstrate that R-GECO1 exhibits a significantly increased signal change compared with ratiometric NES-YC3.6 in response to several stimuli. Due to its superior sensitivity, R-GECO1 is able to report flg22- and chitin-induced Ca(2+) signals on a cellular scale, which allowed identification of defined [Ca(2+)]cyt oscillations in epidermal and guard cells in response to the fungal elicitor chitin. Moreover, we discovered that flg22- and chitin-induced Ca(2+) signals in the root initiate from the elongation zone.
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Affiliation(s)
- Nana F Keinath
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Rainer Waadt
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany; Division of Biological Sciences, Cell and Developmental Biology Section, University of California San Diego, 92093 La Jolla, USA
| | - Rik Brugman
- Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Julian I Schroeder
- Division of Biological Sciences, Cell and Developmental Biology Section, University of California San Diego, 92093 La Jolla, USA
| | - Guido Grossmann
- Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Karin Schumacher
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Melanie Krebs
- Centre for Organismal Studies, Plant Developmental Biology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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62
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Bacha H, Ródenas R, López-Gómez E, García-Legaz MF, Nieves-Cordones M, Rivero RM, Martínez V, Botella MÁ, Rubio F. High Ca(2+) reverts the repression of high-affinity K(+) uptake produced by Na(+) in Solanum lycopersycum L. (var. microtom) plants. JOURNAL OF PLANT PHYSIOLOGY 2015; 180:72-79. [PMID: 25901651 DOI: 10.1016/j.jplph.2015.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 06/04/2023]
Abstract
Potassium (K(+)) is an essential nutrient for plants which is acquired by plant roots through the operation of specific transport systems. Abiotic stress conditions such as salinity impair K(+) nutrition because, in addition to other effects, high salt concentrations in the solution bathing the roots inhibit K(+) uptake systems. This detrimental effect of salinity is exacerbated when external K(+) is very low and the only system capable of mediating K(+) uptake is one with high-affinity for K(+), as that mediated by transporters of the HAK5 type. Increasing external Ca(2+) has been shown to improve K(+) nutrition under salinity and, although the specific mechanisms for this beneficial effect are largely unknown, they are beginning to be understood. The genes encoding the HAK5 transporters are induced by K(+) starvation and repressed by long-term exposure to high Na(+). This occurs in parallel with the hyperpolarization and depolarization of root cell membrane potential. In the present study it is shown in tomato plants that the presence of high Ca(2+) during the K(+) starvation period that leads to LeHAK5 induction, counteracts the repression exerted by high Na(+). High Ca(2+) reduces the Na(+)-induced plasma membrane depolarization of root cells, resorting one of the putative first steps in the low-K(+) signal cascade. This allows proper LeHAK5 expression and functional high-affinity K(+) uptake at the roots. Thus, the maintenance of HAK5-mediated K(+) nutrition under salinity by high Ca(2+) can be regarded as a specific beneficial effect of Ca(2+) contributing to salt tolerance in plants.
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Affiliation(s)
- Hayet Bacha
- Department of Plant Nutrition, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia Spain
| | - Reyes Ródenas
- Department of Plant Nutrition, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia Spain
| | - Elvira López-Gómez
- EPSO Universidad Miguel Hernández, Ctra de Beniel, Km 3.2., 03312 Orihuela, Alicante, Spain
| | | | - Manuel Nieves-Cordones
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier Cedex 2, France
| | - Rosa M Rivero
- Department of Plant Nutrition, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia Spain
| | - Vicente Martínez
- Department of Plant Nutrition, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia Spain
| | - M Ángeles Botella
- EPSO Universidad Miguel Hernández, Ctra de Beniel, Km 3.2., 03312 Orihuela, Alicante, Spain
| | - Francisco Rubio
- Department of Plant Nutrition, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia Spain.
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Straltsova D, Chykun P, Subramaniam S, Sosan A, Kolbanov D, Sokolik A, Demidchik V. Cation channels are involved in brassinosteroid signalling in higher plants. Steroids 2015; 97:98-106. [PMID: 25449770 DOI: 10.1016/j.steroids.2014.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/06/2014] [Accepted: 10/21/2014] [Indexed: 11/27/2022]
Abstract
Brassinosteroids (BRs) are an important class of plant hormones with a multitude of functions. They have been intensively investigated for their biosynthesis, distribution and physiological functions. The aim of this study was to examine possible effects of BRs on the plant plasma membrane cation conductances and Ca(2+) signalling. The wheat root protoplasts (tested by patch-clamping) and excised arabidopsis roots (analysed by Ca(2+)-aequorin chemiluminometry), were used. In the whole-cell plasma membrane patches, 24-epibrassinolide, 28-homobrassionolide or 24-epicastasterone (1 μM) were applied exogenously. 24-Epicastasterone increased the activity of the K(+) efflux conductance in 50% of tested protoplasts while 24-epibrassonolide and 28-homobrassionolide did not modify the plasma membrane currents. Addition of 24-epicastasterone at the cytosolic side (to the pipette solution) resulted in dramatic stimulation of a time-dependent K(+) efflux current (in 30% of protoplasts) and an activation of Ca(2+) influx currents (in 30% of protoplasts). Gadolinium ions, which are blockers of cation channels, inhibited the 24-epicastasterone-induced cation channel activities. In Arabidopsis thaliana plants constitutively expressing aequorin, exogenous 24-epibrassonolide, 28-homobrassionolide and 24-epicastasterone induced a transient elevation of the cytosolic free Ca(2+), which was inhibited by Gd(3+) and mediated by Ca(2+) influx from the bathing solution. In Ca(2+)-aequorin tests, 10 μM of exogenous BRs was the minimal concentration at which statistically significant changes of the cytosolic Ca(2+) were observed. In conclusion, the obtained results suggest that the plasma membrane of root cells contains the brassinosteroid-activated cation-permeable channels, which can probably be involved in rapid regulation of the K(+) homeostasis and Ca(2+) signalling.
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Affiliation(s)
- Darya Straltsova
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Palina Chykun
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Sunitha Subramaniam
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom.
| | - Arifa Sosan
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom.
| | - Dmitriy Kolbanov
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Anatoliy Sokolik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
| | - Vadim Demidchik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Ave., Minsk 220030, Belarus.
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Weiland M, Mancuso S, Baluska F. Signalling via glutamate and GLRs in Arabidopsis thaliana. FUNCTIONAL PLANT BIOLOGY : FPB 2015; 43:1-25. [PMID: 32480438 DOI: 10.1071/fp15109] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/14/2015] [Indexed: 05/14/2023]
Abstract
The genome of Arabidopsis thaliana (L. Heynh.) contains 20 coding sequences for homologues of animal ionotropic glutamate receptors. These glutamate receptor-like receptors act as sensors and mediators of a multitude of exogenous as well as endogenous signals and are found in all analysed plant species. Their molecular structure clearly indicates a function as integral membrane proteins with a ligand-gated ion channel activity. Altered gene expressions and the occurrence of mRNA splice variants confer a high flexibility on the gene as well as on the RNA level. An individual glutamate receptor of A. thaliana is able to bind two different ligands (most probable amino acids and their derivatives), whereas a functional receptor complex is likely to consist of four single proteins. These features enable an immense number of sensitivities against various local and temporal stimuli. This review encompasses the last 15 years of research concerning glutamate signalling and glutamate receptors in plants. It is aimed at summarising their major characteristics and involvements to obtain a broader and farer reaching perspective of these fundamental components of plant signal transduction.
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Affiliation(s)
- Matthias Weiland
- Department of Plant, Soil and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy
| | - Stefano Mancuso
- Department of Plant, Soil and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy
| | - Frantisek Baluska
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany (IZMB), University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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Percey WJ, Shabala L, Breadmore MC, Guijt RM, Bose J, Shabala S. Ion transport in broad bean leaf mesophyll under saline conditions. PLANTA 2014; 240:729-743. [PMID: 25048444 DOI: 10.1007/s00425-014-2117-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 06/20/2014] [Indexed: 06/03/2023]
Abstract
Salt stress reduces the ability of mesophyll tissue to respond to light. Potassium outward rectifying channels are responsible for 84 % of Na (+) induced potassium efflux from mesophyll cells. Modulation in ion transport of broad bean (Vicia faba L.) mesophyll to light under increased apoplastic salinity stress was investigated using vibrating ion-selective microelectrodes (the MIFE technique). Increased apoplastic Na(+) significantly affected mesophyll cells ability to respond to light by modulating ion transport across their membranes. Elevated apoplastic Na(+) also induced a significant K(+) efflux from mesophyll tissue. This efflux was mediated predominately by potassium outward rectifying channels (84 %) and the remainder of the efflux was through non-selective cation channels. NaCl treatment resulted in a reduction in photosystem II efficiency in a dose- and time-dependent manner. In particular, reductions in Fv'/Fm' were linked to K(+) homeostasis in the mesophyll tissue. Increased apoplastic Na(+) concentrations induced vanadate-sensitive net H(+) efflux, presumably mediated by the plasma membrane H(+)-ATPase. It is concluded that the observed pump's activation is essential for the maintenance of membrane potential and ion homeostasis in the cytoplasm of mesophyll under salt stress.
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Affiliation(s)
- William J Percey
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS, 7001, Australia
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Yuan F, Yang H, Xue Y, Kong D, Ye R, Li C, Zhang J, Theprungsirikul L, Shrift T, Krichilsky B, Johnson DM, Swift GB, He Y, Siedow JN, Pei ZM. OSCA1 mediates osmotic-stress-evoked Ca2+ increases vital for osmosensing in Arabidopsis. Nature 2014; 514:367-71. [DOI: 10.1038/nature13593] [Citation(s) in RCA: 417] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/18/2014] [Indexed: 01/05/2023]
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Abstract
Potassium is a macronutrient that is crucial for healthy plant growth. Potassium availability, however, is often limited in agricultural fields and thus crop yields and quality are reduced. Therefore, improving the efficiency of potassium uptake and transport, as well as its utilization, in plants is important for agricultural sustainability. This review summarizes the current knowledge on the molecular mechanisms involved in potassium uptake and transport in plants, and the molecular response of plants to different levels of potassium availability. Based on this information, four strategies for improving potassium use efficiency in plants are proposed; 1) increased root volume, 2) increasing efficiency of potassium uptake from the soil and translocation in planta, 3) increasing mobility of potassium in soil, and 4) molecular breeding new varieties with greater potassium efficiency through marker assisted selection which will require identification and utilization of potassium associated quantitative trait loci.
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Affiliation(s)
- Ryoung Shin
- RIKEN Center for Sustainable Resource Science, Yokohama 230-0045,
Japan
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Coskun D, Britto DT, Kronzucker HJ. The physiology of channel-mediated K+ acquisition in roots of higher plants. PHYSIOLOGIA PLANTARUM 2014; 151:305-12. [PMID: 24697609 DOI: 10.1111/ppl.12174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/17/2014] [Accepted: 01/25/2014] [Indexed: 05/08/2023]
Abstract
K(+) channels are among the best-characterized classes of membrane protein in plants. Nevertheless, in-planta demonstrations of traits emerging from molecular characterizations have often been insufficient or lacking altogether. Such linkages are, however, critical to our basic understanding of plant nutrition and to addressing 'real-world' issues that are faced in environmental and agricultural settings. Here, we cover some of the recent advances in K(+) acquisition with particular focus on voltage-gated K(+) channel functioning and regulation in roots, and highlight where linkages to in-planta behavior have been successfully made and, conversely, where such linkages are yet to be made.
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Affiliation(s)
- Devrim Coskun
- Department of Biological Sciences, University of Toronto, Toronto, ON, M1C 1A4, Canada
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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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Demidchik V. Mechanisms and physiological roles of K+ efflux from root cells. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:696-707. [PMID: 24685330 DOI: 10.1016/j.jplph.2014.01.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 01/05/2014] [Accepted: 01/06/2014] [Indexed: 05/18/2023]
Abstract
Potassium is the most abundant macronutrient, which is involved in a multitude of physiological processes. Potassium uptake in roots is crucial for plants; however, K(+) efflux can also occur and has important functions. Potassium efflux from roots is mainly induced by stresses, such as pathogens, salinity, freezing, oxidants and heavy metals. Reactive oxygen species (ROS) and exogenous purines also cause this reaction. The depolarisation and activation of cation channels are required for K(+) efflux from plant roots. Potassium channels and nonselective cation channels (NSCCs) are involved in this process. Some of them are 'constitutive', while the others require a chemical agent for activation. In Arabidopsis, there are 77 genes that can potentially encode K(+)-permeable channels. Potassium-selective channel genes include 9 Shaker and 6 Tandem-Pore K(+) channels. Genes of NSCCs are more abundant and present by 20 cyclic nucleotide gated channels, 20 ionotropic glutamate receptors, 1 two-pore channel, 10 mechanosensitive-like channels, 2 mechanosensitive 'Mid1-Complementing Activity' channels, 1 mechanosensitive Piezo channel, and 8 annexins. Two Shakers (SKOR and GORK) and several NSCCs are expressed in root cell plasma membranes. SKOR mediates K(+) efflux from xylem parenchyma cells to xylem vessels while GORK is expressed in the epidermis and functions in K(+) release. Both these channels are activated by ROS. The GORK channel activity is stimulated by hydroxyl radicals that are generated in a Ca(2+)-dependent manner in stress conditions, such as salinity or pathogen attack, resulting in dramatic K(+) efflux from root cells. Potassium loss simulates cytosolic proteases and endonucleases, leading to programmed cell death. Other physiological functions of K(+) efflux channels include repolarisation of the plasma membrane during action potentials and the 'hypothetical' function of a metabolic switch, which provides inhibition of energy-consuming biosyntheses and releasing energy for defence and reparation needs.
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Affiliation(s)
- Vadim Demidchik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, Independence Avenue 4, Minsk 220030, Belarus.
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Zörb C, Senbayram M, Peiter E. Potassium in agriculture--status and perspectives. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:656-69. [PMID: 24140002 DOI: 10.1016/j.jplph.2013.08.008] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 05/02/2023]
Abstract
In this review we summarize factors determining the plant availability of soil potassium (K), the role of K in crop yield formation and product quality, and the dependence of crop stress resistance on K nutrition. Average soil reserves of K are generally large, but most of it is not plant-available. Therefore, crops need to be supplied with soluble K fertilizers, the demand of which is expected to increase significantly, particularly in developing regions of the world. Recent investigations have shown that organic exudates of some bacteria and plant roots play a key role in releasing otherwise unavailable K from K-bearing minerals. Thus, breeding for genotypes that have improved mechanisms to gain access to this fixed K will contribute toward more sustainable agriculture, particularly in cropping systems that do not have access to fertilizer K. In K-deficient crops, the supply of sink organs with photosynthates is impaired, and sugars accumulate in source leaves. This not only affects yield formation, but also quality parameters, for example in wheat, potato and grape. As K has beneficial effects on human health, its concentration in the harvest product is a quality parameter in itself. Owing to its fundamental roles in turgor generation, primary metabolism, and long-distance transport, K plays a prominent role in crop resistance to drought, salinity, high light, or cold as well as resistance to pests and pathogens. Despite the abundance of vital roles of K in crop production, an improvement of K uptake and use efficiency has not been a major focus of conventional or transgenic breeding in the past. In addition, current soil analysis methods for K are insufficient for some common soils, posing the risk of imbalanced fertilization. A stronger prioritization of these areas of research is needed to counter declines in soil fertility and to improve food security.
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Affiliation(s)
- Christian Zörb
- Universität Leipzig, Institute of Biology, Botany, Johannisallee 23, 04103 Leipzig, Germany.
| | - Mehmet Senbayram
- Institute of Applied Plant Nutrition, University of Goettingen, Carl-Sprengel-Weg 1, D-37075 Göttingen, Germany
| | - Edgar Peiter
- Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences (IAEW), Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, 06099 Halle (Saale), Germany; Interdisciplinary Centre of Crop Research (IZN), Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, 06099 Halle (Saale), Germany
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Mao D, Chen J, Tian L, Liu Z, Yang L, Tang R, Li J, Lu C, Yang Y, Shi J, Chen L, Li D, Luan S. Arabidopsis Transporter MGT6 Mediates Magnesium Uptake and Is Required for Growth under Magnesium Limitation. THE PLANT CELL 2014; 26:2234-2248. [PMID: 24794135 PMCID: PMC4079380 DOI: 10.1105/tpc.114.124628] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Although magnesium (Mg2+) is the most abundant divalent cation in plant cells, little is known about the mechanism of Mg2+ uptake by plant roots. Here, we report a key function of Magnesium Transport6 (MGT6)/Mitochondrial RNA Splicing2-4 in Mg2+ uptake and low-Mg2+ tolerance in Arabidopsis thaliana. MGT6 is expressed mainly in plant aerial tissues when Mg2+ levels are high in the soil or growth medium. Its expression is highly induced in the roots during Mg2+ deficiency, suggesting a role for MGT6 in response to the low-Mg2+ status in roots. Silencing of MGT6 in transgenic plants by RNA interference (RNAi) resulted in growth retardation under the low-Mg2+ condition, and the phenotype was restored to normal growth after RNAi plants were transferred to Mg2+-sufficient medium. RNAi plants contained lower levels of Mg2+ compared with wild-type plants under low Mg2+ but not under Mg2+-sufficient conditions. Further analysis indicated that MGT6 was localized in the plasma membrane and played a key role in Mg2+ uptake by roots under Mg2+ limitation. We conclude that MGT6 mediates Mg2+ uptake in roots and is required for plant adaptation to a low-Mg2+ environment.
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Affiliation(s)
- Dandan Mao
- College of Life Sciences, Hunan Normal University, Changsha 410081, China Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Jian Chen
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Lianfu Tian
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Zhenhua Liu
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Lei Yang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Renjie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Jian Li
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Changqing Lu
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Yonghua Yang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Jisen Shi
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, MOF Key Laboratory of Forest Genetics and Biotechnology, Nanjing Forestry University, Nanjing 210037, China
| | - Liangbi Chen
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Dongping Li
- College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Sheng Luan
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
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Adams E, Shin R. Transport, signaling, and homeostasis of potassium and sodium in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2014; 56:231-49. [PMID: 24393374 DOI: 10.1111/jipb.12159] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/31/2013] [Indexed: 05/17/2023]
Abstract
Potassium (K⁺) is an essential macronutrient in plants and a lack of K⁺ significantly reduces the potential for plant growth and development. By contrast, sodium (Na⁺), while beneficial to some extent, at high concentrations it disturbs and inhibits various physiological processes and plant growth. Due to their chemical similarities, some functions of K⁺ can be undertaken by Na⁺ but K⁺ homeostasis is severely affected by salt stress, on the other hand. Recent advances have highlighted the fascinating regulatory mechanisms of K⁺ and Na⁺ transport and signaling in plants. This review summarizes three major topics: (i) the transport mechanisms of K⁺ and Na⁺ from the soil to the shoot and to the cellular compartments; (ii) the mechanisms through which plants sense and respond to K⁺ and Na⁺ availability; and (iii) the components involved in maintenance of K⁺/Na⁺ homeostasis in plants under salt stress.
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Affiliation(s)
- Eri Adams
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045, Japan
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Demidchik V, Straltsova D, Medvedev SS, Pozhvanov GA, Sokolik A, Yurin V. Stress-induced electrolyte leakage: the role of K+-permeable channels and involvement in programmed cell death and metabolic adjustment. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1259-70. [PMID: 24520019 DOI: 10.1093/jxb/eru004] [Citation(s) in RCA: 330] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Electrolyte leakage accompanies plant response to stresses, such as salinity, pathogen attack, drought, heavy metals, hyperthermia, and hypothermia; however, the mechanism and physiological role of this phenomenon have only recently been clarified. Accumulating evidence shows that electrolyte leakage is mainly related to K(+) efflux from plant cells, which is mediated by plasma membrane cation conductances. Recent studies have demonstrated that these conductances include components with different kinetics of activation and cation selectivity. Most probably they are encoded by GORK, SKOR, and annexin genes. Hypothetically, cyclic nucleotide-gated channels and ionotropic glutamate receptors can also be involved. The stress-induced electrolyte leakage is usually accompanied by accumulation of reactive oxygen species (ROS) and often results in programmed cell death (PCD). Recent data strongly suggest that these reactions are linked to each other. ROS have been shown to activate GORK, SKOR, and annexins. ROS-activated K(+) efflux through GORK channels results in dramatic K(+) loss from plant cells, which stimulates proteases and endonucleases, and promotes PCD. This mechanism is likely to trigger plant PCD under severe stress. However, in moderate stress conditions, K(+) efflux could play an essential role as a 'metabolic switch' in anabolic reactions, stimulating catabolic processes and saving 'metabolic' energy for adaptation and repair needs.
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Affiliation(s)
- Vadim Demidchik
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, Independence Avenue 4, 220030, Minsk, Belarus
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Monetti E, Kadono T, Tran D, Azzarello E, Arbelet-Bonnin D, Biligui B, Briand J, Kawano T, Mancuso S, Bouteau F. Deciphering early events involved in hyperosmotic stress-induced programmed cell death in tobacco BY-2 cells. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1361-75. [PMID: 24420571 PMCID: PMC3969528 DOI: 10.1093/jxb/ert460] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Hyperosmotic stresses represent one of the major constraints that adversely affect plants growth, development, and productivity. In this study, the focus was on early responses to hyperosmotic stress- (NaCl and sorbitol) induced reactive oxygen species (ROS) generation, cytosolic Ca(2+) concentration ([Ca(2+)]cyt) increase, ion fluxes, and mitochondrial potential variations, and on their links in pathways leading to programmed cell death (PCD). By using BY-2 tobacco cells, it was shown that both NaCl- and sorbitol-induced PCD seemed to be dependent on superoxide anion (O2·(-)) generation by NADPH-oxidase. In the case of NaCl, an early influx of sodium through non-selective cation channels participates in the development of PCD through mitochondrial dysfunction and NADPH-oxidase-dependent O2·(-) generation. This supports the hypothesis of different pathways in NaCl- and sorbitol-induced cell death. Surprisingly, other shared early responses, such as [Ca(2+)]cyt increase and singlet oxygen production, do not seem to be involved in PCD.
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Affiliation(s)
- Emanuela Monetti
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
- LINV-DiSPAA, Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (FI), Italy
| | - Takashi Kadono
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Graduate School of Environmental Engineering, University of Kitakyushu 1-1, Hibikino, Wakamatsu-ku, Kitakyushu 808-0135, Japan
- Laboratory of Crop Science, Department of Plant Resources, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812–8581, Japan
| | - Daniel Tran
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
| | - Elisa Azzarello
- LINV-DiSPAA, Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (FI), Italy
| | - Delphine Arbelet-Bonnin
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
| | - Bernadette Biligui
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
| | - Joël Briand
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
| | - Tomonori Kawano
- LINV-DiSPAA, Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (FI), Italy
- Graduate School of Environmental Engineering, University of Kitakyushu 1-1, Hibikino, Wakamatsu-ku, Kitakyushu 808-0135, Japan
- University of Florence LINV Kitakyushu Research Center (LINV@Kitakyushu), Kitakyushu, Japan
- Université Paris Diderot, Sorbonne Paris Cité, Paris Interdisciplinary Energy Research Institute (PIERI), Paris, France
| | - Stefano Mancuso
- LINV-DiSPAA, Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (FI), Italy
- University of Florence LINV Kitakyushu Research Center (LINV@Kitakyushu), Kitakyushu, Japan
- Université Paris Diderot, Sorbonne Paris Cité, Paris Interdisciplinary Energy Research Institute (PIERI), Paris, France
| | - François Bouteau
- Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain (UMR8236), Paris, France
- Institut de Biologie des Plantes, Bât 630, 91405 Orsay, France
- LINV-DiSPAA, Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (FI), Italy
- University of Florence LINV Kitakyushu Research Center (LINV@Kitakyushu), Kitakyushu, Japan
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Zhou L, Lan W, Jiang Y, Fang W, Luan S. A calcium-dependent protein kinase interacts with and activates a calcium channel to regulate pollen tube growth. MOLECULAR PLANT 2014; 7:369-76. [PMID: 24121288 DOI: 10.1093/mp/sst125] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Calcium, as a ubiquitous second messenger, plays essential roles in tip-growing cells, such as animal neurons, plant pollen tubes, and root hairs. However, little is known concerning the regulatory mechanisms that code and decode Ca(2+) signals in plants. The evidence presented here indicates that a calcium-dependent protein kinase, CPK32, controls polar growth of pollen tubes. Overexpression of CPK32 disrupted the polar growth along with excessive Ca(2+) accumulation in the tip. A search of downstream effector molecules for CPK32 led to identification of a cyclic nucleotide-gated channel, CNGC18, as an interacting partner for CPK32. Co-expression of CPK32 and CNGC18 resulted in activation of CNGC18 in Xenopus oocytes where expression of CNGC18 alone did not exhibit significant calcium channel activity. Overexpression of CNGC18 produced a growth arrest phenotype coupled with accumulation of calcium in the tip, similar to that induced by CPK32 overexpression. Co-expression of CPK32 and CNGC18 had a synergistic effect leading to more severe depolarization of pollen tube growth. These results provide a potential feed-forward mechanism in which calcium-activated CPK32 activates CNGC18, further promoting calcium entry during the elevation phase of Ca(2+) oscillations in the polar growth of pollen tubes.
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Affiliation(s)
- Liming Zhou
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
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78
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Reginato M, Sosa L, Llanes A, Hampp E, Vettorazzi N, Reinoso H, Luna V. Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16:97-106. [PMID: 23869994 DOI: 10.1111/plb.12001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/12/2012] [Indexed: 05/04/2023]
Abstract
Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na(+) accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K(+) supply by maintaining high K(+)/Na(+) discrimination, and maintenance of normal Ca(2+) levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO4(2-)-induced toxicity by Cl(-). Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments.
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Affiliation(s)
- M Reginato
- Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - L Sosa
- Laboratorio de Fisiología Vegetal, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
| | - A Llanes
- Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - E Hampp
- Laboratorio de Suelos, Facultad de Agronomía y Veterinaria, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - N Vettorazzi
- Laboratorio de Química Analítica, Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - H Reinoso
- Laboratorio de Morfología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - V Luna
- Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
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79
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Wu H, Shabala L, Barry K, Zhou M, Shabala S. Ability of leaf mesophyll to retain potassium correlates with salinity tolerance in wheat and barley. PHYSIOLOGIA PLANTARUM 2013; 149:515-27. [PMID: 23611560 DOI: 10.1111/ppl.12056] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/11/2013] [Accepted: 03/19/2013] [Indexed: 05/18/2023]
Abstract
This work investigated the importance of the ability of leaf mesophyll cells to control K(+) flux across the plasma membrane as a trait conferring tissue tolerance mechanism in plants grown under saline conditions. Four wheat (Triticum aestivum and Triticum turgidum) and four barley (Hordeum vulgare) genotypes contrasting in their salinity tolerance were grown under glasshouse conditions. Seven to 10-day-old leaves were excised, and net K(+) and H(+) fluxes were measured from either epidermal or mesophyll cells upon acute 100 mM treatment (mimicking plant failure to restrict Na(+) delivery to the shoot) using non-invasive microelectrode ion flux estimation (the MIFE) system. To enable net ion flux measurements from leaf epidermal cells, removal of epicuticular waxes was trialed with organic solvents. A series of methodological experiments was conducted to test the efficiency of different methods of wax removal, and the impact of experimental procedures on cell viability, in order to optimize the method. A strong positive correlation was found between plants' ability to retain K(+) in salt-treated leaves and their salinity tolerance, in both wheat and especially barley. The observed effects were related to the ionic but not osmotic component of salt stress. Pharmacological experiments have suggested that voltage-gated K(+) -permeable channels mediate K(+) retention in leaf mesophyll upon elevated NaCl levels in the apoplast. It is concluded that MIFE measurements of NaCl-induced K(+) fluxes from leaf mesophyll may be used as an efficient screening tool for breeding in cereals for salinity tissue tolerance.
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Affiliation(s)
- Honghong Wu
- School of Agricultural Science and Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Lana Shabala
- School of Agricultural Science and Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Karen Barry
- School of Agricultural Science and Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Meixue Zhou
- School of Agricultural Science and Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Sergey Shabala
- School of Agricultural Science and Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
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80
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Morgan SH, Lindberg S, Mühling KH. Calcium supply effects on wheat cultivars differing in salt resistance with special reference to leaf cytosol ion homeostasis. PHYSIOLOGIA PLANTARUM 2013; 149:321-328. [PMID: 23413983 DOI: 10.1111/ppl.12036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/18/2013] [Accepted: 01/25/2013] [Indexed: 06/01/2023]
Abstract
Salinity causes changes in cytosolic Ca(2+), [Ca(2+)]cyt, Na(+), [Na(+)]cyt and pH, pH cyt , which induce specific reactions and signals. Reactions causing a rebalancing of the physiological homeostasis of the cytosol could result in plant resistance and growth. Two wheat cultivars, Triticum aestivum, Seds1 and Vinjett, were grown in nutrient solution for 7 days under moderate salinity (0 and 50 mM NaCl) with and without extra addition of 5 mM CaSO4 to investigate the seedling-ion homeostasis under salinity. In the leaf protoplasts [Ca(2+) ]cyt, [Na(+)]cyt and pH cyt were detected using acetoxymethyl esters of the ion-specific dyes, Fura 2, SBFI and BCECF, respectively, and fluorescence microscopy. In addition, both cultivars were grown for 3 weeks at 0, 50 and 125 mM NaCl with, or without, extra addition of 5 mM CaSO4 to detect overall Na(+) and Ca(2+) concentrations in leaves and salinity effects on dry weights. In both cultivars, salinity decreased [Ca(2+)]cyt, while at extra Ca(2+) supplied, [Ca(2+)]cyt increased. The [Ca(2+) ]cyt increase was accompanied by increase in the overall Ca(2+) concentrations in leaves and decrease in the overall Na(+) concentration. Moreover, irrespective of Ca(2+) treatment under salinity, the cultivars reacted in different ways; [Na(+) ]cyt significantly increased only in cv. Vinjett, while pH cyt increased only in cv. Seds1. Even at rather high total Na(+) concentrations, the cytosolic concentrations were kept low in both cultivars. It is discussed whether the increase of [Ca(2+)]cyt and pH cyt can contribute to salt tolerance and if the cytosolic changes are due to changes in overall Ca(2+) and Na(+) concentrations.
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Affiliation(s)
- Sherif H Morgan
- Institute for Plant Nutrition and Soil Science, Christian Albrechts University, Hermann Rodewald Strasse 2, D-24118, Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt
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81
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Golani Y, Kaye Y, Gilhar O, Ercetin M, Gillaspy G, Levine A. Inositol polyphosphate phosphatidylinositol 5-phosphatase9 (At5ptase9) controls plant salt tolerance by regulating endocytosis. MOLECULAR PLANT 2013; 6:1781-1794. [PMID: 23658066 DOI: 10.1093/mp/sst072] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phosphatidylinositol 5-phosphatases (5PTases) that hydrolyze the 5' position of the inositol ring are key components of membrane trafficking system. Recently, we reported that mutation in At5PTase7 gene reduced production of reactive oxygen species (ROS) and decreased expression of stress-responsive genes, resulting in increased salt sensitivity. Here, we describe an even more salt-sensitive 5ptase mutant, At5ptase9, which also hydrolyzes the 5' phosphate groups specifically from membrane-bound phosphatidylinositides. Interestingly, the mutants were more tolerant to osmotic stress. We analyzed the main cellular processes that may be affected by the mutation, such as production of ROS, influx of calcium, and induction of salt-response genes. The At5ptase9 mutants showed reduced ROS production and Ca(2+) influx, as well as decreased fluid-phase endocytosis. Inhibition of endocytosis by phenylarsine oxide or Tyrphostin A23 in wild-type plants blocked these responses. Induction of salt-responsive genes in wild-type plants was also suppressed by the endocytosis inhibitors. Thus, inhibition of endocytosis in wild-type plants mimicked the salt stress responses, observed in the At5ptase9 mutants. In summary, our results show a key non-redundant role of At5PTase7 and 9 isozymes, and underscore the localization of membrane-bound PtdIns in regulating plant salt tolerance by coordinating the endocytosis, ROS production, Ca(2+) influx, and induction of stress-responsive genes.
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Affiliation(s)
- Yael Golani
- a Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Givat-Ram Campus, Jerusalem 91904, Israel
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82
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Jiang C, Belfield EJ, Cao Y, Smith JAC, Harberd NP. An Arabidopsis soil-salinity-tolerance mutation confers ethylene-mediated enhancement of sodium/potassium homeostasis. THE PLANT CELL 2013; 25:3535-52. [PMID: 24064768 PMCID: PMC3809548 DOI: 10.1105/tpc.113.115659] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 08/28/2013] [Accepted: 09/03/2013] [Indexed: 05/18/2023]
Abstract
High soil Na concentrations damage plants by increasing cellular Na accumulation and K loss. Excess soil Na stimulates ethylene-induced soil-salinity tolerance, the mechanism of which we here define via characterization of an Arabidopsis thaliana mutant displaying transpiration-dependent soil-salinity tolerance. This phenotype is conferred by a loss-of-function allele of ethylene overproducer1 (ETO1; mutant alleles of which cause increased production of ethylene). We show that lack of ETO1 function confers soil-salinity tolerance through improved shoot Na/K homeostasis, effected via the ethylene resistant1-constitutive triple response1 ethylene signaling pathway. Under transpiring conditions, lack of ETO1 function reduces root Na influx and both stelar and xylem sap Na concentrations, thereby restricting root-to-shoot delivery of Na. These effects are associated with increased accumulation of respiratory burst oxidase homolog F (RBOHF)-dependent reactive oxygen species in the root stele. Additionally, lack of ETO1 function leads to significant enhancement of tissue K status by an RBOHF-independent mechanism associated with elevated high-affinity K(+) TRANSPORTER5 transcript levels. We conclude that ethylene promotes soil-salinity tolerance via improved Na/K homeostasis mediated by RBOHF-dependent regulation of Na accumulation and RBOHF-independent regulation of K accumulation.
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Affiliation(s)
- Caifu Jiang
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Eric J. Belfield
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Yi Cao
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - J. Andrew C. Smith
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Nicholas P. Harberd
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
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83
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Saleh L, Plieth C. A9C sensitive Cl⁻-accumulation in A. thaliana root cells during salt stress is controlled by internal and external calcium. PLANT SIGNALING & BEHAVIOR 2013; 8:e24259. [PMID: 23603974 PMCID: PMC3925454 DOI: 10.4161/psb.24259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/11/2013] [Accepted: 03/11/2013] [Indexed: 05/11/2023]
Abstract
The involvement of chloride in salt stress symptoms and salt tolerance mechanisms in plants has been less investigated in the past. Therefore, we studied the salt-induced chloride influx in Arabidopsis expressing the GFP-based anion indicator Clomeleon. High salt concentrations induce two phases of chloride influx. The fast kinetic phase is likely caused by membrane depolarization, and is assumed to be mediated by channels. This is followed by a slower "saturation" phase, where chloride is accumulated in the cytoplasm. Both phases of chloride uptake are dependent on the presence of external calcium. In general: with high [Ca (2+)] less chloride is accumulated in the cytoplasm. Surprisingly, also the internal calcium availability has an impact on chloride transport. A complete block of the second phase of chloride influx is achieved by the anion channel blocker A9C and trivalent cations (La (3+), Gd (3+), and Al (3+)). Other channel blockers and diuretics were found to inhibit the process partially. The results suggest that several transporter species are involved here, including electroneutral cation-chloride-cotransporters, and a part of chloride possibly enters the cells through cation channels after salt application.
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Affiliation(s)
- Livia Saleh
- Zentrum fur Biochemie und Molekularbiologie; Christian-Albrechts-Universitat; Kiel, Germany
| | - Christoph Plieth
- Zentrum fur Biochemie und Molekularbiologie; Christian-Albrechts-Universitat; Kiel, Germany
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84
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Coskun D, Britto DT, Li M, Oh S, Kronzucker HJ. Capacity and plasticity of potassium channels and high-affinity transporters in roots of barley and Arabidopsis. PLANT PHYSIOLOGY 2013; 162:496-511. [PMID: 23553635 PMCID: PMC3641226 DOI: 10.1104/pp.113.215913] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 03/31/2013] [Indexed: 05/03/2023]
Abstract
The role of potassium (K(+)) transporters in high- and low-affinity K(+) uptake was examined in roots of intact barley (Hordeum vulgare) and Arabidopsis (Arabidopsis thaliana) plants by use of (42)K radiotracing, electrophysiology, pharmacology, and mutant analysis. Comparisons were made between results from barley and five genotypes of Arabidopsis, including single and double knockout mutants for the high-affinity transporter, AtHAK5, and the Shaker-type channel, AtAKT1. In Arabidopsis, steady-state K(+) influx at low external K(+) concentration ([K(+)]ext = 22.5 µm) was predominantly mediated by AtAKT1 when high-affinity transport was inhibited by ammonium, whereas in barley, by contrast, K(+) channels could not operate below 100 µm. Withdrawal of ammonium resulted in an immediate and dramatic stimulation of K(+) influx in barley, indicating a shift from active to passive K(+) uptake at low [K(+)]ext and yielding fluxes as high as 36 µmol g (root fresh weight)(-1) h(-1) at 5 mm [K(+)]ext, among the highest transporter-mediated K(+) fluxes hitherto reported. This ammonium-withdrawal effect was also established in all Arabidopsis lines (the wild types, atakt1, athak5, and athak5 atakt1) at low [K(+)]ext, revealing the concerted involvement of several transport systems. The ammonium-withdrawal effect coincided with a suppression of K(+) efflux and a significant hyperpolarization of the plasma membrane in all genotypes except athak5 atakt1, could be sustained over 24 h, and resulted in increased tissue K(+) accumulation. We discuss key differences and similarities in K(+) acquisition between two important model systems and reveal novel aspects of K(+) transport in planta.
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Affiliation(s)
- Devrim Coskun
- Department of Biological Sciences, University of Toronto, Toronto, Ontario, Canada M1C 1A4
| | - Dev T. Britto
- Department of Biological Sciences, University of Toronto, Toronto, Ontario, Canada M1C 1A4
| | - Mingyuan Li
- Department of Biological Sciences, University of Toronto, Toronto, Ontario, Canada M1C 1A4
| | - Saehong Oh
- Department of Biological Sciences, University of Toronto, Toronto, Ontario, Canada M1C 1A4
| | - Herbert J. Kronzucker
- Department of Biological Sciences, University of Toronto, Toronto, Ontario, Canada M1C 1A4
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85
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Vincill ED, Clarin AE, Molenda JN, Spalding EP. Interacting glutamate receptor-like proteins in Phloem regulate lateral root initiation in Arabidopsis. THE PLANT CELL 2013; 25:1304-13. [PMID: 23590882 PMCID: PMC3663269 DOI: 10.1105/tpc.113.110668] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 03/29/2013] [Accepted: 04/04/2013] [Indexed: 05/18/2023]
Abstract
Molecular, genetic, and electrophysiological evidence indicates that at least one of the plant Glu receptor-like molecules, GLR3.4, functions as an amino acid-gated Ca²⁺channel at the plasma membrane. The aspect of plant physiology, growth, or development to which GLR3.4 contributes is an open question. Protein localization studies performed here provide important information. In roots, GLR3.4 and the related GLR3.2 protein were present primarily in the phloem, especially in the vicinity of the sieve plates. GLR3.3 was expressed in most cells of the growing primary root but was not enriched in the phloem, including the sieve plate area. GLR3.2 and GLR3.4 physically interacted with each other better than with themselves as evidenced by a biophotonic assay performed in human embryonic kidney cells and Nicotiana benthamiana leaf cells. GLR3.3 interacted poorly with itself or the other two GLRs. Mutations in GLR3.2, GLR3.4, or GLR3.2 and GLR3.4 caused the same and equally severe phenotype, namely, a large overproduction and aberrant placement of lateral root primordia. Loss of GLR3.3 did not affect lateral root primordia. These results support the hypothesis that apoplastic amino acids acting through heteromeric GLR3.2/GLR3.4 channels affect lateral root development via Ca²⁺ signaling in the phloem.
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Affiliation(s)
- Eric D Vincill
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA
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86
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Abstract
As one of the most important mineral nutrient elements, potassium (K(+)) participates in many plant physiological processes and determines the yield and quality of crop production. In this review, we summarize K(+) signaling processes and K(+) transport regulation in higher plants, especially in plant responses to K(+)-deficiency stress. Plants perceive external K(+) fluctuations and generate the initial K(+) signal in root cells. This signal is transduced into the cytoplasm and encoded as Ca(2+) and reactive oxygen species signaling. K(+)-deficiency-induced signals are subsequently decoded by cytoplasmic sensors, which regulate the downstream transcriptional and posttranslational responses. Eventually, plants produce a series of adaptive events in both physiological and morphological alterations that help them survive K(+) deficiency.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Plant Physiology and Biochemistry, National Center of Plant Gene Research (Beijing), College of Biological Sciences, China Agricultural University, Beijing 100193, China
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87
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Horie T, Karahara I, Katsuhara M. Salinity tolerance mechanisms in glycophytes: An overview with the central focus on rice plants. RICE (NEW YORK, N.Y.) 2012; 5:11. [PMID: 27234237 PMCID: PMC5520831 DOI: 10.1186/1939-8433-5-11] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 06/22/2012] [Indexed: 05/04/2023]
Abstract
Elevated Na(+) levels in agricultural lands are increasingly becoming a serious threat to the world agriculture. Plants suffer osmotic and ionic stress under high salinity due to the salts accumulated at the outside of roots and those accumulated at the inside of the plant cells, respectively. Mechanisms of salinity tolerance in plants have been extensively studied and in the recent years these studies focus on the function of key enzymes and plant morphological traits. Here, we provide an updated overview of salt tolerant mechanisms in glycophytes with a particular interest in rice (Oryza sativa) plants. Protective mechanisms that prevent water loss due to the increased osmotic pressure, the development of Na(+) toxicity on essential cellular metabolisms, and the movement of ions via the apoplastic pathway (i.e. apoplastic barriers) are described here in detail.
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Affiliation(s)
- Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567 Japan
| | - Ichirou Karahara
- Department of Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555 Japan
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, 20-1, Chuo-2-chome, Kurashiki, Okayama, 710-0046 Japan
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88
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Caballero F, Botella MA, Rubio L, Fernández JA, Martínez V, Rubio F. A Ca(2+)-sensitive system mediates low-affinity K(+) uptake in the absence of AKT1 in Arabidopsis plants. PLANT & CELL PHYSIOLOGY 2012; 53:2047-59. [PMID: 23054389 DOI: 10.1093/pcp/pcs140] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
K(+) acquisition by Arabidopsis roots is mainly mediated by the high-affinity K(+) transporter AtHAK5 and the inward-rectifier K(+) channel AtAKT1. This model is probably universal to plants. Mutant plants lacking these two systems (athak5,atakt1) take up K(+) and grow when the external K(+) concentration is above a certain level, indicating that an additional transport system may compensate for the absence of AtHAK5 and AtAKT1. Here we describe that this alternative system is essential for providing sufficient K(+) to sustain growth of athak5,atakt1 plants. This system is especially sensitive to Ca(2+), Mg(2+), Ba(2+) and La(3+), it transports Cs(+) and its activity is reduced by cyclic nucleotides. These results suggest that a Ca(2+)-permeable voltage-independent non-selective cation channel, probably belonging to the cyclic nucleotide gated channel (CNGC) family, may provide the pathway for K(+) uptake in athak5,atakt1 plants. The genes encoding the two members of the CNGC family that have been described as mediating root K(+) uptake, AtCNGC3 and AtCNGC10, are not up-regulated in athak5,atakt1 plants, excluding overexpression of these genes as a compensatory mechanism. On the other hand, an increased driving force for K(+) in athak5,atakt1 plants due to a hyperpolarization of the membrane potential of its root cells is also discarded. The identification of this unknown system may provide tools to improve plant K(+) nutrition in conditions where AtAKT1 functionality is reduced, such as under salinity. In addition, this system may constitute an important pathway for accumulation of toxic cations such as Cs(+) or radiocesium ((137)Cs(+)), and could play a role in phytoremediation.
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Affiliation(s)
- Fernando Caballero
- Departamento de Nutrición, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia, Spain
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89
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ROS-mediated vascular homeostatic control of root-to-shoot soil Na delivery in Arabidopsis. EMBO J 2012; 31:4359-70. [PMID: 23064146 PMCID: PMC3501220 DOI: 10.1038/emboj.2012.273] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 09/12/2012] [Indexed: 01/12/2023] Open
Abstract
Sodium (Na) is ubiquitous in soils, and is transported to plant shoots via transpiration through xylem elements in the vascular tissue. However, excess Na is damaging. Accordingly, control of xylem-sap Na concentration is important for maintenance of shoot Na homeostasis, especially under Na stress conditions. Here we report that shoot Na homeostasis of Arabidopsis thaliana plants grown in saline soils is conferred by reactive oxygen species (ROS) regulation of xylem-sap Na concentrations. We show that lack of A. thaliana respiratory burst oxidase protein F (AtrbohF; an NADPH oxidase catalysing ROS production) causes hypersensitivity of shoots to soil salinity. Lack of AtrbohF-dependent salinity-induced vascular ROS accumulation leads to increased Na concentrations in root vasculature cells and in xylem sap, thus causing delivery of damaging amounts of Na to the shoot. We also show that the excess shoot Na delivery caused by lack of AtrbohF is dependent upon transpiration. We conclude that AtrbohF increases ROS levels in wild-type root vasculature in response to raised soil salinity, thereby limiting Na concentrations in xylem sap, and in turn protecting shoot cells from transpiration-dependent delivery of excess Na.
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90
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Sawidis T, Krystallidis P, Veros D, Chettri M. A study of air pollution with heavy metals in Athens city and Attica basin using evergreen trees as biological indicators. Biol Trace Elem Res 2012; 148:396-408. [PMID: 22410948 DOI: 10.1007/s12011-012-9378-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/26/2012] [Indexed: 10/28/2022]
Abstract
Concentrations of five metals (cadmium, chromium, copper, nickel and lead) were determined in tree leaves collected from 13 areas of the Attica basin and Athens city, Greece. Geographical distribution patterns were investigated, and factors affecting toxic element accumulation in trees were discussed. The mean heavy metal content in the tree leaves is described in the descending order of copper>lead>nickel>chromium>cadmium. Generally, the most damaged areas have been proved to be those near the city center and in the vicinity of the Attica highway. The geomorphological relief of the area plays an important role in the dispersion of airborne particles from pollution sources to the surrounding area. Areas on the NE region are also polluted mainly due to wind directions. In Citrus aurantium leaves, with relatively impermeable cuticle, high chromium, copper and nickel concentration would be possibly caused only by significant stomatal uptake. The conifer tree Pinus brutia providing a rough leaf surface also showed elevated concentrations, especially of cadmium and lead. The thick waxy cuticle of the sclerophyllous broad-leaved Olea europaea forms a smooth sheet increasing the barrier properties of the leaf epidermis and causing a reduction in leaf permeability. The dense trichomes of the abaxial epidermis of Olea europaea also act as a pollution screen keeping away the air particles from the epidermis stomata. The presence of a certain metal within the leaf cells could reduce the uptake or toxicity of some others.
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Affiliation(s)
- Thomas Sawidis
- Department of Botany, University of Thessaloniki, 54124 Thessaloniki, Greece.
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91
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Li J, Bao S, Zhang Y, Ma X, Mishra-Knyrim M, Sun J, Sa G, Shen X, Polle A, Chen S. Paxillus involutus strains MAJ and NAU mediate K(+)/Na(+) homeostasis in ectomycorrhizal Populus x canescens under sodium chloride stress. PLANT PHYSIOLOGY 2012; 159:1771-86. [PMID: 22652127 PMCID: PMC3425212 DOI: 10.1104/pp.112.195370] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/28/2012] [Indexed: 05/20/2023]
Abstract
Salt-induced fluxes of H(+), Na(+), K(+), and Ca(2+) were investigated in ectomycorrhizal (EM) associations formed by Paxillus involutus (strains MAJ and NAU) with the salt-sensitive poplar hybrid Populus × canescens. A scanning ion-selective electrode technique was used to measure flux profiles in non-EM roots and axenically grown EM cultures of the two P. involutus isolates to identify whether the major alterations detected in EM roots were promoted by the fungal partner. EM plants exhibited a more pronounced ability to maintain K(+)/Na(+) homeostasis under salt stress. The influx of Na(+) was reduced after short-term (50 mm NaCl, 24 h) and long-term (50 mm NaCl, 7 d) exposure to salt stress in mycorrhizal roots, especially in NAU associations. Flux data for P. involutus and susceptibility to Na(+)-transport inhibitors indicated that fungal colonization contributed to active Na(+) extrusion and H(+) uptake in the salinized roots of P. × canescens. Moreover, EM plants retained the ability to reduce the salt-induced K(+) efflux, especially under long-term salinity. Our study suggests that P. involutus assists in maintaining K(+) homeostasis by delivering this nutrient to host plants and slowing the loss of K(+) under salt stress. EM P. × canescens plants exhibited an enhanced Ca(2+) uptake ability, whereas short-term and long-term treatments caused a marked Ca(2+) efflux from mycorrhizal roots, especially from NAU-colonized roots. We suggest that the release of additional Ca(2+) mediated K(+)/Na(+) homeostasis in EM plants under salt stress.
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Affiliation(s)
| | | | | | - Xujun Ma
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
| | - Manika Mishra-Knyrim
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
| | - Jian Sun
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
| | - Gang Sa
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
| | - Xin Shen
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
| | - Andrea Polle
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, People’s Republic of China (J.L., S.B., Y.Z., X.M., J.S., G.S., X.S., S.C.)
- School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo 454000, People’s Republic of China (J.L.); and
- Büsgen-Institut, Forstbotanik und Baumphysiologie, Georg-August Universität Göttingen, Gottingen, Germany (M.M.-K., A.P.)
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92
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Vincill ED, Bieck AM, Spalding EP. Ca(2+) conduction by an amino acid-gated ion channel related to glutamate receptors. PLANT PHYSIOLOGY 2012; 159:40-6. [PMID: 22447719 PMCID: PMC3375973 DOI: 10.1104/pp.112.197509] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 03/23/2012] [Indexed: 05/17/2023]
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93
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Schulze LM, Britto DT, Li M, Kronzucker HJ. A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a 24Na+/42K+ study. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:2479-89. [PMID: 22268152 PMCID: PMC3346217 DOI: 10.1093/jxb/err419] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 05/19/2023]
Abstract
Soil sodium, while toxic to most plants at high concentrations, can be beneficial at low concentrations, particularly when potassium is limiting. However, little is known about Na(+) uptake in this 'high-affinity' range. New information is provided here with an insight into the transport characteristics, mechanism, and ecological significance of this phenomenon. High-affinity Na(+) and K(+) fluxes were investigated using the short-lived radiotracers (24)Na and (42)K, under an extensive range of measuring conditions (variations in external sodium, and in nutritional and pharmacological agents). This work was supported by electrophysiological, compartmental, and growth analyses. Na(+) uptake was extremely sensitive to all treatments, displaying properties of high-affinity K(+) transporters, K(+) channels, animal Na(+) channels, and non-selective cation channels. K(+), NH(4)(+), and Ca(2+) suppressed Na(+) transport biphasically, yielding IC(50) values of 30, 10, and <5 μM, respectively. Reciprocal experiments showed that K(+) influx is neither inhibited nor stimulated by Na(+). Sodium efflux constituted 65% of influx, indicating a futile cycle. The thermodynamic feasibility of passive channel mediation is supported by compartmentation and electrophysiological data. Our study complements recent advances in the molecular biology of high-affinity Na(+) transport by uncovering new physiological foundations for this transport phenomenon, while questioning its ecological relevance.
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Affiliation(s)
| | | | | | - Herbert J. Kronzucker
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Toronto, ON, Canada M1C 1A4
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94
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95
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Ma L, Zhang H, Sun L, Jiao Y, Zhang G, Miao C, Hao F. NADPH oxidase AtrbohD and AtrbohF function in ROS-dependent regulation of Na⁺/K⁺homeostasis in Arabidopsis under salt stress. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:305-17. [PMID: 21984648 DOI: 10.1093/jxb/err280] [Citation(s) in RCA: 259] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Maintaining cellular Na(+)/K(+) homeostasis is pivotal for plant survival in saline environments. However, knowledge about the molecular regulatory mechanisms of Na(+)/K(+) homeostasis in plants under salt stress is largely lacking. In this report, the Arabidopsis double mutants atrbohD1/F1 and atrbohD2/F2, in which the AtrbohD and AtrbohF genes are disrupted and generation of reactive oxygen species (ROS) is pronouncedly inhibited, were found to be much more sensitive to NaCl treatments than wild-type (WT) and the single null mutant atrbohD1 and atrbohF1 plants. Furthermore, the two double mutant seedlings had significantly higher Na(+) contents, lower K(+) contents, and resultant greater Na(+)/K(+) ratios than the WT, atrbohD1, and atrbohF1 under salt stress. Exogenous H(2)O(2) can partially reverse the increased effects of NaCl on Na(+)/K(+) ratios in the double mutant plants. Pre-treatments with diphenylene iodonium chloride, a widely used inhibitor of NADPH oxidase, clearly enhanced the Na(+)/K(+) ratios in WT seedlings under salt stress. Moreover, NaCl-inhibited inward K(+) currents were arrested, and NaCl-promoted increases in cytosolic Ca(2+) and plasma membrane Ca(2+) influx currents were markedly attenuated in atrbohD1/F1 plants. No significant differences in the sensitivity to osmotic or oxidative stress among the WT, atrbohD1, atrbohF1, atrbohD1/F1, and atrbohD2/F2 were observed. Taken together, these results strongly suggest that ROS produced by both AtrbohD and AtrbohF function as signal molecules to regulate Na(+)/K(+) homeostasis, thus improving the salt tolerance of Arabidopsis.
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Affiliation(s)
- Liya Ma
- State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, College of Life Science, Henan University, Kaifeng 475004, China
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96
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Li L, Liu X, Peijnenburg WJGM, Zhao J, Chen X, Yu J, Wu H. Pathways of cadmium fluxes in the root of the halophyte Suaeda salsa. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 75:1-7. [PMID: 21943551 DOI: 10.1016/j.ecoenv.2011.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/05/2011] [Accepted: 09/11/2011] [Indexed: 05/27/2023]
Abstract
Halophyte plants offer a greater potential for phytoremediation research for reducing the levels of toxic metals from saline soils than salt sensitive plants. Using the scanning ion-selective electrode technique, we analyzed the pattern and rate of Cd(2+) fluxes at different regions of the root apex of Suaeda salsa. The Cd(2+) influx in the rhizosphere was greatest near the root tip (within 150μm of the tip). The results indicated that Cd(2+) influx into roots was significantly suppressed by the pre-treatment or in the presence of two kinds of Ca(2+) channel blockers; LaCl(3) and verapamil. The Cd(2+) influx was also reduced by N-ethylmaleimide, a thiol blocker. Cd content determination and labeling of Cd using fluorescent dye support our conclusion. The results of this study provide a more stable theoretical basis for the phytoremediation of Cd contamination in saline soils of coastal zones.
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Affiliation(s)
- Lianzhen Li
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, People's Republic of China
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97
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Volotovski ID. Role of calcium ions in photosignaling processes in a plant cell. Biophysics (Nagoya-shi) 2011. [DOI: 10.1134/s0006350911050253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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98
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Zepeda-Jazo I, Velarde-Buendía AM, Enríquez-Figueroa R, Bose J, Shabala S, Muñiz-Murguía J, Pottosin II. Polyamines interact with hydroxyl radicals in activating Ca(2+) and K(+) transport across the root epidermal plasma membranes. PLANT PHYSIOLOGY 2011; 157:2167-80. [PMID: 21980172 PMCID: PMC3327209 DOI: 10.1104/pp.111.179671] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 10/03/2011] [Indexed: 05/18/2023]
Abstract
Reactive oxygen species (ROS) are integral components of the plant adaptive responses to environment. Importantly, ROS affect the intracellular Ca(2+) dynamics by activating a range of nonselective Ca(2+)-permeable channels in plasma membrane (PM). Using patch-clamp and noninvasive microelectrode ion flux measuring techniques, we have characterized ionic currents and net K(+) and Ca(2+) fluxes induced by hydroxyl radicals (OH(•)) in pea (Pisum sativum) roots. OH(•), but not hydrogen peroxide, activated a rapid Ca(2+) efflux and a more slowly developing net Ca(2+) influx concurrent with a net K(+) efflux. In isolated protoplasts, OH(•) evoked a nonselective current, with a time course and a steady-state magnitude similar to those for a K(+) efflux in intact roots. This current displayed a low ionic selectivity and was permeable to Ca(2+). Active OH(•)-induced Ca(2+) efflux in roots was suppressed by the PM Ca(2+) pump inhibitors eosine yellow and erythrosine B. The cation channel blockers gadolinium, nifedipine, and verapamil and the anionic channel blockers 5-nitro-2(3-phenylpropylamino)-benzoate and niflumate inhibited OH(•)-induced ionic currents in root protoplasts and K(+) efflux and Ca(2+) influx in roots. Contrary to expectations, polyamines (PAs) did not inhibit the OH(•)-induced cation fluxes. The net OH(•)-induced Ca(2+) efflux was largely prolonged in the presence of spermine, and all PAs tested (spermine, spermidine, and putrescine) accelerated and augmented the OH(•)-induced net K(+) efflux from roots. The latter effect was also observed in patch-clamp experiments on root protoplasts. We conclude that PAs interact with ROS to alter intracellular Ca(2+) homeostasis by modulating both Ca(2+) influx and efflux transport systems at the root cell PM.
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Affiliation(s)
| | | | | | | | | | | | - Igor I. Pottosin
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, 28045 Colima, Mexico (I.Z.-J., A.M.V.-B., R.E.-F., J.M.-M., I.I.P.); School of Agricultural Science, University of Tasmania, Hobart, Tasmania 7001, Australia (J.B., S.S.)
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99
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Trono D, Soccio M, Laus MN, Pastore D. Potassium channel-oxidative phosphorylation relationship in durum wheat mitochondria from control and hyperosmotic-stressed seedlings. PLANT, CELL & ENVIRONMENT 2011; 34:2093-108. [PMID: 21819416 DOI: 10.1111/j.1365-3040.2011.02407.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Durum wheat mitochondria (DWM) possess an ATP-inhibited K(+) channel, the plant mitoK(ATP) (PmitoK(ATP) ), which is activated under environmental stress to control mitochondrial ROS production. To do this, PmitoK(ATP) collapses membrane potential (ΔΨ), thus suggesting mitochondrial uncoupling. We tested this point by studying oxidative phosphorylation (OXPHOS) in DWM purified from control seedlings and from seedlings subjected both to severe mannitol and NaCl stress. In severely-stressed DWM, the ATP synthesis via OXPHOS, continuously monitored by a spectrophotometric assay, was about 90% inhibited when the PmitoK(ATP) was activated by KCl. Contrarily, in control DWM, although PmitoK(ATP) collapsed ΔΨ, ATP synthesis, as well as coupling [respiratory control (RC) ratio and ratio between phosphorylated ADP and reduced oxygen (ADP/O)] checked by oxygen uptake experiments, were unaffected. We suggest that PmitoK(ATP) may play an important defensive role at the onset of the environmental/oxidative stress by preserving energy in a crucial moment for cell and mitochondrial bioenergetics. Consistently, under moderate mannitol stress, miming an early stress condition, the channel may efficiently control reactive oxygen species (ROS) generation (about 35-fold from fully open to closed state) without impairing ATP synthesis. Anyway, if the stress significantly proceeds, the PmitoK(ATP) becomes fully activated by decrease of ATP concentration (25-40%) and increase of activators [free fatty acids (FFAs) and superoxide anion], thus impairing ATP synthesis.
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Affiliation(s)
- Daniela Trono
- CRA - Centro di Ricerca per la Cerealicoltura, S.S. 16 Km 675, Dipartimento di Scienze Agroambientali, Chimica e Difesa Vegetale, Università di Foggia, Via Napoli 25, Italy
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100
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Jamil A, Riaz S, Ashraf M, Foolad MR. Gene Expression Profiling of Plants under Salt Stress. CRITICAL REVIEWS IN PLANT SCIENCES 2011; 30:435-458. [PMID: 0 DOI: 10.1080/07352689.2011.605739] [Citation(s) in RCA: 228] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
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