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Pereira PN, Gaspar M, Smith JAC, Mercier H. Ammonium intensifies CAM photosynthesis and counteracts drought effects by increasing malate transport and antioxidant capacity in Guzmania monostachia. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1993-2003. [PMID: 29462338 PMCID: PMC6018993 DOI: 10.1093/jxb/ery054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 02/07/2018] [Indexed: 05/25/2023]
Abstract
Guzmania monostachia (Bromeliaceae) is a tropical epiphyte capable of up-regulating crassulacean acid metabolism (CAM) in its photosynthetic tissues in response to changing nutrient and water availability. Previous studies have shown that under drought there is a gradient of increasing CAM expression from the basal (youngest) to the apical (oldest) portion of the leaves, and additionally that nitrogen deficiency can further increase CAM intensity in the leaf apex of this bromeliad. The present study investigated the inter-relationships between nitrogen source (nitrate and/or ammonium) and water deficit in regulating CAM expression in G. monostachia leaves. The highest CAM activity was observed under ammonium nutrition in combination with water deficit. This was associated with enhanced activity of the key enzyme phosphoenolpyruvate carboxylase, elevated rates of ATP- and PPi-dependent proton transport at the vacuolar membrane in the presence of malate, and increased transcript levels of the vacuolar malate channel-encoding gene, ALMT. Water deficit was consistently associated with higher levels of total soluble sugars, which were maximal under ammonium nutrition, as were the activities of several antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase). Thus, ammonium nutrition, whilst associated with the highest degree of CAM induction in G. monostachia, also mitigates the effects of water deficit by osmotic adjustment and can limit oxidative damage in the leaves of this bromeliad under conditions that may be typical of its epiphytic habitat.
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Affiliation(s)
- Paula Natália Pereira
- Department of Botany, Institute of Biosciences, University of São Paulo, CEP, São Paulo, SP, Brazil
| | - Marília Gaspar
- Department of Plant Physiology and Biochemistry, Institute of Botany, CEP, São Paulo, SP, Brazil
| | - J Andrew C Smith
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Helenice Mercier
- Department of Botany, Institute of Biosciences, University of São Paulo, CEP, São Paulo, SP, Brazil
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Frei B, Eisenach C, Martinoia E, Hussein S, Chen XZ, Arrivault S, Neuhaus HE. Purification and functional characterization of the vacuolar malate transporter tDT from Arabidopsis. J Biol Chem 2018; 293:4180-4190. [PMID: 29367340 DOI: 10.1074/jbc.ra117.000851] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/08/2018] [Indexed: 11/06/2022] Open
Abstract
The exact transport characteristics of the vacuolar dicarboxylate transporter tDT from Arabidopsis are elusive. To overcome this limitation, we combined a range of experimental approaches comprising generation/analysis of tDT overexpressors, 13CO2 feeding and quantification of 13C enrichment, functional characterization of tDT in proteoliposomes, and electrophysiological studies on vacuoles. tdt knockout plants showed decreased malate and increased citrate concentrations in leaves during the diurnal light-dark rhythm and after onset of drought, when compared with wildtypes. Interestingly, under the latter two conditions, tDT overexpressors exhibited malate and citrate levels opposite to tdt knockout plants. Highly purified tDT protein transports malate and citrate in a 1:1 antiport mode. The apparent affinity for malate decreased with decreasing pH, whereas citrate affinity increased. This observation indicates that tDT exhibits a preference for dianion substrates, which is supported by electrophysiological analysis on intact vacuoles. tDT also accepts fumarate and succinate as substrates, but not α-ketoglutarate, gluconate, sulfate, or phosphate. Taking tDT as an example, we demonstrated that it is possible to reconstitute a vacuolar metabolite transporter functionally in proteoliposomes. The displayed, so far unknown counterexchange properties of tDT now explain the frequently observed reciprocal concentration changes of malate and citrate in leaves from various plant species. tDT from Arabidopsis is the first member of the well-known and widely present SLC13 group of carrier proteins, exhibiting an antiport mode of transport.
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Affiliation(s)
- Benedikt Frei
- From Pflanzenphysiologie, Universität Kaiserslautern, Erwin Schrödinger-Strasse, D-67653 Kaiserslautern, Germany
| | - Cornelia Eisenach
- the Institut für Pflanzenbiologie, Universität Zürich, CH-8008 Zürich, Switzerland
| | - Enrico Martinoia
- the Institut für Pflanzenbiologie, Universität Zürich, CH-8008 Zürich, Switzerland
| | - Shaimaa Hussein
- the Faculty of Medicine and Dentistry, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada, and
| | - Xing-Zhen Chen
- the Faculty of Medicine and Dentistry, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada, and
| | - Stéphanie Arrivault
- the Max Planck-Institute of Molecular Plant Physiology, Wissenschaftspark Potsdam-Golm, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - H Ekkehard Neuhaus
- From Pflanzenphysiologie, Universität Kaiserslautern, Erwin Schrödinger-Strasse, D-67653 Kaiserslautern, Germany,
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Pereira PN, Smith JAC, Mercier H. Nitrate enhancement of CAM activity in two Kalanchoë species is associated with increased vacuolar proton transport capacity. PHYSIOLOGIA PLANTARUM 2017; 160:361-372. [PMID: 28393374 DOI: 10.1111/ppl.12578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/24/2017] [Accepted: 03/05/2017] [Indexed: 06/07/2023]
Abstract
Among species that perform CAM photosynthesis, members of the genus Kalanchoë have been studied frequently to investigate the effect of environmental factors on the magnitude of CAM activity. In particular, different nitrogen sources have been shown to influence the rate of nocturnal CO2 fixation and organic-acid accumulation in several species of Kalanchoë. However, there has been little investigation of the interrelationship between nitrogen source (nitrate versus ammonium), concentration and the activity of the vacuolar proton pumps responsible for driving nocturnal organic-acid accumulation in these species. In the present study with Kalanchoë laxiflora and Kalanchoë delagoensis cultivated on different nitrogen sources, both species were found to show highest total nocturnal organic-acid accumulation and highest rates of ATP- and PPi-dependent vacuolar proton transport on 2.5 mM nitrate, whereas plants cultivated on 5.0 mM ammonium showed the lowest values. In both species malate was the principal organic-acid accumulated during the night, but the second-most accumulated organic-acid was fumarate for K. laxiflora and citrate for K. delagoensis. Higher ATP- and PPi-dependent vacuolar proton transport rates and greater nocturnal acid accumulation were observed in K. delagoensis compared with K. laxiflora. These results show that the effect of nitrogen source on CAM activity in Kalanchoë species is reflected in corresponding differences in activity of the tonoplast proton pumps responsible for driving sequestration of these acids in the vacuole of CAM-performing cells.
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Affiliation(s)
- Paula Natália Pereira
- Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
| | | | - Helenice Mercier
- Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
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Pereira PN, Smith JAC, Purgatto E, Mercier H. Proton and anion transport across the tonoplast vesicles in bromeliad species. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:646-653. [PMID: 32480595 DOI: 10.1071/fp16293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 03/10/2017] [Indexed: 06/11/2023]
Abstract
Crassulacean acid metabolism (CAM) is one of the key innovations in the Neotropical family Bromeliaceae that has enabled many of its species to occupy seasonally water-limited terrestrial environments or microclimatically arid epiphytic niches. However, the relationship between CAM activity and the transport processes responsible for vacuolar organic-acid accumulation at night has not been systematically explored in this family. In the present investigation, ATP- and PPi-dependent proton transport rates were studied in tonoplast membrane vesicles isolated from leaves of six CAM and one C3 species of bromeliads. A consistent feature of these species was the high activity of the tonoplast ATP-driven H+ pump, which, when averaged across the seven species tested, showed a higher specific activity than the tonoplast PPi-driven H+ pump. For all CAM species, the rate of ATP-dependent proton transport into the tonoplast vesicles was strongly influenced by the nature of the balancing organic-acid anion, which displayed the following order of effectiveness: fumarate>malate>citrate. Measurements of leaf organic-acid content in six CAM bromeliads at dusk and dawn showed that nocturnal accumulation of malate exceeded citrate by a factor of ~2.4-20.0-fold in five of six bromeliad species used in this study, demonstrating a close correlation between the CAM rhythm and the intrinsic properties of the vacuolar membrane across which these organic acids are transported.
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Affiliation(s)
- Paula Natália Pereira
- Department of Botany, Institute of Biosciences, Universidade de São Paulo, CEP 05508-090, São Paulo, SP, Brazil
| | | | - Eduardo Purgatto
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, Universidade de São Paulo,CEP 05422-970 São Paulo, SP, Brazil
| | - Helenice Mercier
- Department of Botany, Institute of Biosciences, Universidade de São Paulo, CEP 05508-090, São Paulo, SP, Brazil
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Sun X, Zhu A, Liu S, Sheng L, Ma Q, Zhang L, Nishawy EME, Zeng Y, Xu J, Ma Z, Cheng Y, Deng X. Integration of metabolomics and subcellular organelle expression microarray to increase understanding the organic acid changes in post-harvest citrus fruit. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:1038-1053. [PMID: 23758915 DOI: 10.1111/jipb.12083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
Citric acid plays an important role in fresh fruit flavor and its adaptability to post-harvest storage conditions. In order to explore organic acid regulatory mechanisms in post-harvest citrus fruit, systematic biological analyses were conducted on stored Hirado Buntan Pummelo (HBP; Citrus grandis) fruits. High-performance capillary electrophoresis, subcellular organelle expression microarray, real-time quantitative reverse transcription polymerase chain reaction, gas chromatography mass spectrometry (GC-MS), and conventional physiological and biochemical analyses were undertaken. The results showed that the concentration of organic acids in HBP underwent a regular fluctuation. GC-MS-based metabolic profiling indicated that succinic acid, γ-aminobutyric acid (GABA), and glutamine contents increased, but 2-oxoglutaric acid content declined, which further confirmed that the GABA shunt may have some regulatory roles in organic acid catabolism processes. In addition, the concentration of organic acids was significantly correlated with senescence-related physiological processes, such as hydrogen peroxide content as well as superoxide dismutase and peroxidase activities, which showed that organic acids could be regarded as important parameters for measuring citrus fruit post-harvest senescence processes.
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Affiliation(s)
- Xiaohua Sun
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Seidel T, Siek M, Marg B, Dietz KJ. Energization of vacuolar transport in plant cells and its significance under stress. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 304:57-131. [PMID: 23809435 DOI: 10.1016/b978-0-12-407696-9.00002-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plant vacuole is of prime importance in buffering environmental perturbations and in coping with abiotic stress caused by, for example, drought, salinity, cold, or UV. The large volume, the efficient integration in anterograde and retrograde vesicular trafficking, and the dynamic equipment with tonoplast transporters enable the vacuole to fulfill indispensible functions in cell biology, for example, transient and permanent storage, detoxification, recycling, pH and redox homeostasis, cell expansion, biotic defence, and cell death. This review first focuses on endomembrane dynamics and then summarizes the functions, assembly, and regulation of secretory and vacuolar proton pumps: (i) the vacuolar H(+)-ATPase (V-ATPase) which represents a multimeric complex of approximately 800 kDa, (ii) the vacuolar H(+)-pyrophosphatase, and (iii) the plasma membrane H(+)-ATPase. These primary proton pumps regulate the cytosolic pH and provide the driving force for secondary active transport. Carriers and ion channels modulate the proton motif force and catalyze uptake and vacuolar compartmentation of solutes and deposition of xenobiotics or secondary compounds such as flavonoids. ABC-type transporters directly energized by MgATP complement the transport portfolio that realizes the multiple functions in stress tolerance of plants.
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Affiliation(s)
- Thorsten Seidel
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany.
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Shimada T, Nakano R, Shulaev V, Sadka A, Blumwald E. Vacuolar citrate/H+ symporter of citrus juice cells. PLANTA 2006; 224:472-80. [PMID: 16440212 DOI: 10.1007/s00425-006-0223-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 12/29/2005] [Indexed: 05/06/2023]
Abstract
We have isolated a cDNA, designated Citrus sinensis citrate transporter 1 CsCit1 encoding a novel vacuolar citrate/symporter. Immunoblots using antibodies raised against CsCit1 showed that the protein is localized to the juice sac cell vacuoles. The highest expression of CsCit1 and the amount of protein in the juice sac cell vacuoles coincided with the developmental stage at which the vacuolar citrate content began declining with the concomitant increase in vacuolar pH. Vacuoles from Sacharomyces cereviseae expressing CsCit1 displayed a citrate-dependent H(+) efflux, and our results clearly demonstrate that CsCit1 is able to mediate the electroneutral co-transport of H(+) and citrate ions, since the citrate-dependent H(+) fluxes are not affected by changing the electrical potential difference across the tonoplast. The roles of CsCit1 in mediating citrate efflux from the vacuole and on citric acid homoestasis in Citrus juice sac cells are discussed.
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Affiliation(s)
- Takehiko Shimada
- Department of Plant Sciences, Mail Stop 5, University of California, One Shields Ave, Davis, 95616, USA
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Holtum JAM, Smith JAC, Neuhaus HE. Intracellular transport and pathways of carbon flow in plants with crassulacean acid metabolism. FUNCTIONAL PLANT BIOLOGY : FPB 2005; 32:429-449. [PMID: 32689145 DOI: 10.1071/fp04189] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2004] [Accepted: 02/22/2005] [Indexed: 06/11/2023]
Abstract
The massive daily reciprocal transfer of carbon between acids and carbohydrates that is unique to crassulacean acid metabolism (CAM) involves extensive and regulated transport of metabolites between chloroplasts, vacuoles, the cytosol and mitochondria. In this review of the CAM pathways of carbon flow and intracellular transport, we highlight what is known and what has been postulated. For three of the four CAM pathway variants currently known (malic enzyme- or PEP carboxykinase-type decarboxylase, and starch- or soluble sugar-type carbohydrate storage), the mechanisms of intracellular transport are still hypothetical and have yet to be demonstrated experimentally. Even in malic enzyme starch-storing species such as Kalanchoë daigremontiana Hamet et Perr. and Mesembryanthemum crystallinum L., the best-described variants of plants with the second-most common mode of photosynthetic carbon metabolism known, no tonoplast or mitochondrial transporter has been functionally described at a molecular level.
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Affiliation(s)
- Joseph A M Holtum
- School of Tropical Biology, James Cook University, Townsville, Qld 4811, Australia
| | - J Andrew C Smith
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - H Ekkehard Neuhaus
- Universität Kaiserslautern, Pflanzenphysiologie, Erwin Schrödinger-Strasse, D-67653 Kaiserslautern, Germany
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Hurth MA, Suh SJ, Kretzschmar T, Geis T, Bregante M, Gambale F, Martinoia E, Neuhaus HE. Impaired pH homeostasis in Arabidopsis lacking the vacuolar dicarboxylate transporter and analysis of carboxylic acid transport across the tonoplast. PLANT PHYSIOLOGY 2005; 137:901-10. [PMID: 15728336 PMCID: PMC1065391 DOI: 10.1104/pp.104.058453] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 01/14/2005] [Accepted: 01/17/2005] [Indexed: 05/17/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) mutants lacking the tonoplastic malate transporter AttDT (A. thaliana tonoplast dicarboxylate transporter) and wild-type plants showed no phenotypic differences when grown under standard conditions. To identify putative metabolic changes in AttDT knock-out plants, we provoked a metabolic scenario connected to an increased consumption of dicarboxylates. Acidification of leaf discs stimulated dicarboxylate consumption and led to extremely low levels of dicarboxylates in mutants. To investigate whether reduced dicarboxylate concentrations in mutant leaf cells and, hence, reduced capacity to produce OH(-) to overcome acidification might affect metabolism, we measured photosynthetic oxygen evolution under conditions where the cytosol is acidified. AttDT::tDNA protoplasts showed a much stronger inhibition of oxygen evolution at low pH values when compared to wild-type protoplasts. Apparently citrate, which is present in higher amounts in knock-out plants, is not able to replace dicarboxylates to overcome acidification. To raise more information on the cellular level, we performed localization studies of carboxylates. Although the total pool of carboxylates in mutant vacuoles was nearly unaltered, these organelles contained a lower proportion of malate and fumarate and a higher proportion of citrate when compared to wild-type vacuoles. These alterations concur with the observation that radioactively labeled malate and citrate are transported into Arabidopsis vacuoles by different carriers. In addition, wild-type vacuoles and corresponding organelles from AttDT::tDNA mutants exhibited similar malate channel activities. In conclusion, these results show that Arabidopsis vacuoles contain at least two transporters and a channel for dicarboxylates and citrate and that the activity of AttDT is critical for regulation of pH homeostasis.
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Affiliation(s)
- Marco Alois Hurth
- Technische Universität Kaiserslautern, Pflanzenphysiologie, D-67653 Kaiserslautern, Germany
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Chen LS, Nose A. Day-night changes of energy-rich compounds in crassulacean acid metabolism (CAM) species utilizing hexose and starch. ANNALS OF BOTANY 2004; 94:449-55. [PMID: 15277250 PMCID: PMC4242190 DOI: 10.1093/aob/mch165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND AIMS Plants with crassulacean acid metabolism (CAM) can be divided into two groups according to the major carbohydrates used for malic acid synthesis, either polysaccharide (starch) or monosaccharide (hexose). This is related to the mechanism and affects energy metabolism in the two groups. In Kalanchoë pinnata and K. daigremontiana, which utilize starch, ATP-dependent phosphofructokinase (tonoplast inorganic pyrophosphatase) activity is greater than inorganic pyrophosphate-dependent phosphofructokinase (tonoplast adenosine triphosphatase) activity, but the reverse is the case in pineapple (Ananas comosus) utilizing hexose. To test the hypothesis that the energy metabolism of the two groups differs, day-night changes in the contents of ATP, ADP, AMP, inorganic phosphate (Pi), phosphoenolpyruvate (PEP) and inorganic pyrophosphate (PPi) in K. pinnata and K. daigremontiana leaves and in pineapple chlorenchyma were analysed. METHODS The contents of energy-rich compounds were measured spectrophotometrically in extracts of tissue sampled in the light and dark, using potted plants, kept for 15 d before the experiments in a growth chamber. KEY RESULTS In the three species, ATP content and adenylate energy charge (AEC) increased in the dark and decreased in the light, in contrast to ADP and AMP. Changes in ATP and AEC were greater in Kalanchoë leaves than in pineapple chlorenchyma. PPi content in the three species increased in the dark, but on illumination it decreased rapidly and substantially, remaining little changed through the rest of the light period. Pi content of Kalanchoë leaves did not change between dark and light, whereas Pi in pineapple chlorenchyma increased in the dark and decreased in the light, and the changes were far greater than in Kalanchoë leaves. Light-dark changes in PEP content in the three species were similar. CONCLUSIONS These results corroborate our hypothesis that day-night changes in the contents of energy-rich compounds differ between CAM species and are related to the carbohydrate used for malic acid synthesis.
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Affiliation(s)
- Li-Song Chen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China.
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Hafke JB, Hafke Y, Smith JAC, Lüttge U, Thiel G. Vacuolar malate uptake is mediated by an anion-selective inward rectifier. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2003; 35:116-28. [PMID: 12834407 DOI: 10.1046/j.1365-313x.2003.01781.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Electrophysiological studies using the patch-clamp technique were performed on isolated vacuoles from leaf mesophyll cells of the crassulacean acid metabolism (CAM) plant Kalanchoë daigremontiana to characterize the malate transport system responsible for nocturnal malic acid accumulation. In the presence of malate on both sides of the membrane, the current-voltage relations of the tonoplast were dominated by a strongly inward-rectifying anion-selective channel that was active at cytoplasmic-side negative voltages. Rectification of the macroscopic conductance was reflected in the voltage-dependent gating of a 3-pS malate-selective ion channel, which showed a half-maximal open probability at -43 mV. Also, the time-averaged unitary currents following a step to a negative voltage corresponded to the time-dependent kinetics of the macroscopic currents, suggesting that the activity of this channel underlies the anion-selective inward rectifier. The inward rectifier showed saturation kinetics with respect to malate (apparent Km of 2.5 mm malate2- activity), a selectivity sequence of fumarate2- > malate2- > Cl- > maleate2- approximately citrate3-, and greater activity at higher pH values (with an apparent pK of 7.1 and maximum activity at around pH 8.0). All these properties were in close agreement with the characteristics of malate transport observed in isolated tonoplast vesicles. Further, 100 microM niflumate reversibly blocked the activity of the 3-pS channel and inhibited both macroscopic currents and malate transport into tonoplast vesicles to the same extent. The macroscopic current densities recorded at physiological voltages and the estimated channel density of 0.2 microm-2 are sufficient to account for the observed rates of nocturnal malic acid accumulation in this CAM plant, suggesting that the 3-pS, inward-rectifying, anion-selective channel represents the principal pathway for malate influx into the vacuole.
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Affiliation(s)
- Jens B Hafke
- Institut für Botanik, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287 Darmstadt, Germany
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Martinoia E, Massonneau A, Frangne N. Transport processes of solutes across the vacuolar membrane of higher plants. PLANT & CELL PHYSIOLOGY 2000; 41:1175-86. [PMID: 11092901 DOI: 10.1093/pcp/pcd059] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The central vacuole is the largest compartment of a mature plant cell and may occupy more than 80% of the total cell volume. However, recent results indicate that beside the large central vacuole, several small vacuoles may exist in a plant cell. These vacuoles often belong to different classes and can be distinguished either by their contents in soluble proteins or by different types of a major vacuolar membrane protein, the aquaporins. Two vacuolar proton pumps, an ATPase and a PPase energize vacuolar uptake of most solutes. The electrochemical gradient generated by these pumps can be utilized to accumulate cations by a proton antiport mechanism or anions due to the membrane potential difference. Uptake can be catalyzed by channels or by transporters. Growing evidence shows that for most ions more than one transporter/channel exist at the vacuolar membrane. Furthermore, plant secondary products may be accumulated by proton antiport mechanisms. The transport of some solutes such as sucrose is energized in some plants but occurs by facilitated diffusion in others. A new class of transporters has been discovered recently: the ABC type transporters are directly energized by MgATP and do not depend on the electrochemical force. Their substrates are organic anions formed by conjugation, e.g. to glutathione. In this review we discuss the different transport processes occurring at the vacuolar membrane and focus on some new results obtained in this field.
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Affiliation(s)
- E Martinoia
- Laboratoire de Physiologie Végétale, Institut de Botanique, Université de Neuchâtel, Rue Emile Argand 13, CH-2007 Neuchâtel, Switzerland.
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Lüttge U, Pfeifer T, Fischer-Schliebs E, Ratajczak R. The role of vacuolar malate-transport capacity in crassulacean acid metabolism and nitrate nutrition. Higher malate-transport capacity in ice plant after crassulacean acid metabolism-induction and in tobacco under nitrate nutrition. PLANT PHYSIOLOGY 2000; 124:1335-48. [PMID: 11080309 PMCID: PMC59231 DOI: 10.1104/pp.124.3.1335] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2000] [Accepted: 07/14/2000] [Indexed: 05/23/2023]
Abstract
Anion uptake by isolated tonoplast vesicles was recorded indirectly via increased H(+)-transport by H(+)-pumping of the V-ATPase due to dissipation of the electrical component of the electrochemical proton gradient, Deltamu(H+), across the membrane. ATP hydrolysis by the V-ATPase was measured simultaneously after the Palmgren test. Normalizing for ATP-hydrolysis and effects of chloride, which was added to the assays as a stimulating effector of the V-ATPase, a parameter, J(mal)(rel), of apparent ATP-dependent malate-stimulated H(+)-transport was worked out as an indirect measure of malate transport capacity. This allowed comparison of various species and physiological conditions. J(mal)(rel) was high in the obligate crassulacean acid metabolism (CAM) species Kalanchoë daigremontiana Hamet et Perrier, it increased substantially after CAM induction in ice plant (Mesembryanthemum crystallinum), and it was positively correlated with NO(3)(-) nutrition in tobacco (Nicotiana tabacum). For tobacco this was confirmed by measurements of malate transport energized via the V-PPase. In ice plant a new polypeptide of 32-kD apparent molecular mass appeared, and a 33-kD polypeptide showed higher levels after CAM induction under conditions of higher J(mal)(rel). It is concluded that tonoplast malate transport capacity plays an important role in physiological regulation in CAM and NO(3)(-) nutrition and that a putative malate transporter must be within the 32- to 33-kD polypeptide fraction of tonoplast proteins.
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Affiliation(s)
- U Lüttge
- Institute of Botany, Darmstadt University of Technology, Schnittspahnstrasse 3-5, D-64287 Darmstadt, Germany.
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Barkla BJ, Pantoja O. PHYSIOLOGY OF ION TRANSPORT ACROSS THE TONOPLAST OF HIGHER PLANTS. ACTA ACUST UNITED AC 1996; 47:159-184. [PMID: 15012286 DOI: 10.1146/annurev.arplant.47.1.159] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vacuole of plant cells plays an important role in the homeostasis of the cell. It is involved in the regulation of cytoplasmic pH, sequestration of toxic ions and xenobiotics, regulation of cell turgor, storage of amino acids, sugars and CO2 in the form of malate, and possibly as a source for elevating cytoplasmic calcium. All these activities are driven by two primary active transport mechanisms present in the vacuolar membrane (tonoplast). These two mechanisms employ high-energy metabolites to pump protons into the vacuole, establishing a proton electrochemical potential that mediates the transport of a diverse range of solutes. Within the past few years, great advances at the molecular and functional levels have been made on the characterization and identification of these mechanisms. The aim of this review is to summarize these studies in the context of the physiology of the plant cell.
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Affiliation(s)
- Bronwyn J. Barkla
- Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, UNAM, Cuernavaca, Morelos, Mexico, 62271
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Smith JAC, Ingram J, Tsiantis MS, Barkla BJ, Bartholomew DM, Bettey M, Pantoja O, Pennington AJ. Transport Across the Vacuolar Membrane in CAM Plants. CRASSULACEAN ACID METABOLISM 1996. [DOI: 10.1007/978-3-642-79060-7_5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Rentsch D, Görlach J, Vogt E, Amrhein N, Martinoia E. The tonoplast-associated citrate binding protein (CBP) of Hevea brasiliensis. Photoaffinity labeling, purification, and cloning of the corresponding gene. J Biol Chem 1995; 270:30525-31. [PMID: 8530484 DOI: 10.1074/jbc.270.51.30525] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A detailed comparison of citrate uptake into the vacuole-like lutoids of rubber tree (Hevea brasiliensis Muell. Arg.) and of malate and citrate transport into barley (Hordeum vulgare L.) vacuoles revealed very similar transport specificities. In order to identify proteins mediating the transport, two photoreactive analogues (N'-(2-hydroxy-5-azido)-diazo-N-3,5-benzenedicarboxylic acid and 5-azidoisophthalic acid) of malate/citrate were synthesized and found to efficiently inhibit citrate uptake into barley vacuoles (Ki = 18 microM) and Hevea lutoid vesicles (Ki = 27 microM). In vacuoles from both plant species, these photoaffinity probes specifically labeled a single protein with a molecular mass of 23.6 kDa. This citrate binding protein (CBP) was purified to homogeneity from Hevea lutoids, and amino acid sequences were determined for NH2-terminal and tryptic peptides. Using degenerate oligonucleotides of the NH2-terminal sequence, a cDNA coding for the CBP protein of Hevea was isolated. The cDNA codes for a precursor protein of 238 amino acids, containing an NH2-terminal 31-amino acid signal sequence for endoplasmic reticulum targeting, a prerequisite for vacuolar localization. The mature CBP does not show significant sequence similarities to any known primary protein structure and thus represents a member of a novel class of proteins.
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Affiliation(s)
- D Rentsch
- Institute of Plant Sciences, Swiss Federal Institute of Technology, Zürich, Switzerland
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18
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Bettey M, Smith JA. Dicarboxylate transport at the vacuolar membrane of the CAM plant Kalanchoë daigremontiana: sensitivity to protein-modifying and sulphydryl reagents. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1152:270-9. [PMID: 8218327 DOI: 10.1016/0005-2736(93)90258-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Malate is widespread as a charge-balancing anion in plant vacuoles and plays a central role in nocturnal CO2 assimilation in crassulacean acid metabolism (CAM). To characterize the malate transport system at the vacuolar membrane of CAM plants, tonoplast vesicles were prepared from leaf mesophyll cells of the crassulacean plant Kalanchoë daigremontiana. Dicarboxylate uptake, assayed by a membrane-filtration method using [14C]malate or [14C]succinate, displayed saturation kinetics with apparent Km values of 4.0 mM (malate) and 1.8 mM (succinate); competition experiments indicated that both anions were transported by the same system. Dicarboxylate uptake was stimulated severalfold by activation of the tonoplast H(+)-ATPase or H(+)-PPiase, an effect inhibitable by ionophore. Passive (non-energized) dicarboxylate uptake was sensitive to the sulphydryl reagents N-ethylmaleimide and p-chloromercuribenzene sulphonate, as well as to a range of protein modifiers. In particular, inhibition by pyridoxal phosphate was completely substrate-protectable, and that by phenylglyoxal partially so, thus implicating at least one lysine residue and perhaps also an arginine residue in the substrate-recognition site of the transport protein. The involvement of one or more critical lysine residue was supported by analysis of the initial phase of inhibition by pyridoxal phosphate: this showed pseudo-first-order kinetics with a reaction order of 1.03 +/- 0.13 and a Kd for substrate protection close to the apparent Km for dicarboxylate uptake.
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Affiliation(s)
- M Bettey
- Department of Plant Sciences, University of Oxford, UK
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19
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Dietz KJ, Canut H, Marigo G. Identification of an essential histidine residue at the active site of the tonoplast malate carrier in Catharanthus roseus cells. J Membr Biol 1992; 129:137-43. [PMID: 1433274 DOI: 10.1007/bf00219509] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The involvement of a histidyl residue in the binding or translocation step was investigated in the malate carrier at the tonoplast of Catharanthus roseus cells. The transport rate was strongly stimulated when the pH of the incubation medium was decreased from pH 7.0 to 5.0. The histidine-specific reagent diethylpyrocarbonate (DEPC) efficiently inhibited the activity of the malate carrier. Inhibition developed rapidly and was completed after 5 min at a concentration of 2 mM DEPC. The original substrate, malate, partially protected the carrier from inactivation by DEPC. Other organic acids (citrate, quinate) which are known to affect the malate transport of isolated vacuoles or tonoplast vesicles also showed protective properties. Inhibition of malate transport on tonoplast vesicles can also be achieved by photooxidation in the presence of the dye Rose Bengal. Malate also proved to protect against inactivation. The results strongly support the notion that a histidyl residue(s) is involved either in the binding or translocation of malate and that the protonation of the histidyl residue is essential to provide a high rate of malate transport.
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Affiliation(s)
- K J Dietz
- Signaux et Messages Cellulaires chez les Végétaux, URA CNRS n.1457, Université Paul Sabatier, Toulouse, France
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20
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Sze H, Ward JM, Lai S. Vacuolar H(+)-translocating ATPases from plants: structure, function, and isoforms. J Bioenerg Biomembr 1992; 24:371-81. [PMID: 1400282 DOI: 10.1007/bf00762530] [Citation(s) in RCA: 162] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The vacuolar H(+)-translocating ATPase (V-type ATPase) plays a central role in the growth and development of plant cells. In a mature cell, the vacuole is the largest intracellular compartment, occupying about 90% of the cell volume. The proton electrochemical gradient (acid inside) formed by the vacuolar ATPase provides the primary driving force for the transport of numerous ions and metabolites against their electrochemical gradients. The uptake and release of solutes across the vacuolar membrane is fundamental to many cellular processes, such as osmoregulation, signal transduction, and metabolic regulation. Vacuolar ATPases may also reside on endomembranes, such as Golgi and coated vesicles, and thus may participate in intracellular membrane traffic, sorting, and secretion. Plant vacuolar ATPases are large complexes (400-650 kDa) composed of 7-10 different subunits. The peripheral sector of 5-6 subunits includes the nucleotide-binding catalytic and regulatory subunits of approximately 70 and approximately 60 kDa, respectively. Six copies of the 16-kDa proteolipid together with 1-3 other subunits make up the integral sector that forms the H+ conducting pathway. Isoforms of plant vacuolar ATPases are suggested by the variations in subunit composition observed among and within plant species, and by the presence of a small multigene family encoding the 16-kDa and 70-kDa subunits. Multiple genes may encode isoforms with specific properties required to serve the diverse functions of vacuoles and endomembrane compartments.
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Affiliation(s)
- H Sze
- Department of Botany, University of Maryland, College Park 20742
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21
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Wilkins MB. Tansley Review No. 37 Circadian rhythms: their origin and control. THE NEW PHYTOLOGIST 1992; 121:347-375. [PMID: 33874151 DOI: 10.1111/j.1469-8137.1992.tb02936.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This article reviews the circadian rhythm of carbon dioxide metabolism in leaves of the Crassulacean plant Bryophyllum (Kalanchoë) fedtsckenkoi which persists both in continuous darkness and a CO2 -free atmosphere, and in continuous light and normal air. Under both conditions the rhythm is due to the periodic activity of the enzyme phosphoenolpyruvate carboxylase (PEPc). The physiological characteristics of the rhythm are described in detail and, from these characteristics, hypotheses are advanced to account for both the generation of the rhythm and the regulation of its phase and period by environmental factors. The periodic activity of PEPc is ascribed to the periodic accumulation of an allosteric inhibitor, malate, in the cytoplasm and its subsequent removal either to the vacuole in continuous darkness, or by metabolism in continuous light. Also involved in the generation of the rhythm is a periodic change in the sensitivity of PEPc to malate inhibition due to the periodic phosphorylation and dephosphorylation of PEPc which changes its K1 by a factor of 10 from 30 to 0.3 mM and vice versa. This periodic phosphorylation of PEPc is apparently achieved by the periodic synthesis and breakdown of a PEPc kinase which phosphorylates the enzyme on a serine residue; dephosphorylation is achieved by a type 2A phosphatase which shows no rhythmic variation. The induction of phase shifts in the rhythm in continuous darkness and CO2 -free air has been explained in terms of light and high-temperature activated gates or channels in the tonoplast which, when open, allow malate to diffuse between the vacuole and cytoplasm. For the rhythm in continuous light and normal air phase, control by environmental signals can be attributed to changes in the malate levels in critical cell compartments, or in particular cell populations such as the stomatal guard cells, due to regulation of the malate synthesizing enzyme system involving PEPc, and malic enzyme which is responsible for malate metabolism. The role of the stomata in the generation of the rhythm is also discussed. The biochemical events which appear to give rise to the well-studied circadian rhythms in leaf movement in Samanea and Albizza, in luminescence in Gonyaulax polyedra and in the synthesis of the chlorophyll a/b binding protein are also reviewed in an attempt to identify similarities between these events and those involved in the Bryophyllum rhythm. Finally, the somewhat similar nature of the genes apparently responsible for circadian rhythmicity in Neurospora and Drosophila are discussed, and suggestions made for utilizing anti-sense nucleic acid technology in the further elucidation of the critical biochemical events involved in the basic, temperature-compensated circadian oscillator in living organisms. CONTENTS Summary 347 I. Introduction 348 II. Occurrence of circadian rhythms 348 III. Physiological characteristics of circadian rhythms 349 IV. Biochemical and molecular events involved in the circadian rhythm in Bryophyllum leaves 362 V. Biochemical and molecular events involved in the origin and control of circadian rhythmicity in other organisms 366 VI. Genetic studies 370 VII. Conclusion 371 References 372.
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Warren M, Smith JA, Apps DK. Rapid purification and reconstitution of a plant vacuolar ATPase using Triton X-114 fractionation: subunit composition and substrate kinetics of the H(+)-ATPase from the tonoplast of Kalanchoë daigremontiana. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1106:117-25. [PMID: 1533789 DOI: 10.1016/0005-2736(92)90229-f] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A rapid procedure for the purification and reconstitution into proteoliposomes of the H(+)-translocating ATPase of plant vacuolar membranes is reported. It involves fractionation of the tonoplast with Triton X-114, resolubilization of the ATPase with octyl glucoside in the presence of a mixture of phosphatidylcholine, phosphatidylserine and cholesterol (27:53:20, by weight), and removal of the detergent by gel-filtration. Starting with partially purified vacuolar membranes, the procedure can be accomplished in about 2 hours. It has been applied to the H(+)-ATPase from the crassulacean plant Kalanchoë daigremontiana, from which it yields vesicles with a specific ATPase activity of about 3 mumol/min per mg protein. The purified enzyme contains polypeptides of apparent molecular mass 72, 57, 48, 42, 39, 33 and 16 kDa; these polypeptides also co-sediment on centrifugation of the solubilized ATPase through glycerol gradients. The 16-kDa subunit is labelled with [14C]dicyclohexylcarbodiimide. There is no evidence for a larger ATPase subunit in this preparation. The reconstituted ATPase proteoliposomes undergo ATP-dependent acidification, which can be measured by quenching of the fluorescence of 9-aminoacridine. The initial rate of fluorescence quenching is a measure of the rate of H+ translocation, and is directly proportional to the vesicle protein concentration, so the preparation is suitable for studying the kinetics of the tonoplast H(+)-ATPase. The dependence of the rate of fluorescence quenching on the concentration of MgATP is well fitted by the Michaelis equation, with a Km value about 30 microM. ATP can be replaced by dATP, ITP, GTP, UTP or CTP, and Mg2+ by Mn2+ or Ca2+; kinetic parameters for these substrates are reported. In contrast, hydrolysis of MgATP shows complex kinetics, suggestive either of negative cooperativity between nucleotide-binding sites, or of two non-interacting catalytic sites. Both the hydrolytic and the H(+)-translocating activities of the proteoliposomes are inhibited by nitrate, though not in parallel, the latter activity being the more sensitive. Both activities are inhibited in parallel by bafilomycin A1, which does not produce complete inhibition; the bafilomycin-insensitive component has complex ATPase kinetics similar to those of the uninhibited enzyme.
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Affiliation(s)
- M Warren
- Department of Biochemistry, University of Edinburgh, UK
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Martinoia E, Vogt E, Rentsch D, Amrhein N. Functional reconstitution of the malate carrier of barley mesophyll vacuoles in liposomes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1062:271-8. [PMID: 2004114 DOI: 10.1016/0005-2736(91)90402-t] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The malate carrier of barley (Hordeum vulgare L.) mesophyll vacuoles was highly purified by chromatography on hydroxyapatite followed by affinity-chromatography using 5-amino-1,2,3-benzenetricarboxylic acid as ligand. The carrier, reconstituted in asolectin liposomes, had properties similar to those described previously for the carrier in intact vacuoles (Martinoia, E., Flügge, U.I., Kaiser, G., Heber, U. and Heldt, H.W. (1985) Biochim. Biophys. Acta 806, 311-319). The apparent Km for malate uptake was 2-3 mM, and the uptake was inhibited by other carboxylic acids (preferentially tricarboxylic). The sulfhydryl reagent, p-chloromercuribenzenesulfonate, as well as the anion transport inhibitor 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid, also inhibited malate uptake. The transport was dependent on the membrane potential with an optimum at about 35 mV.
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Affiliation(s)
- E Martinoia
- Swiss Federal Institute of Technology, Institute of Plant Sciences, ETH-Zentrum, Zürich
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