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A channel that allows inwardly directed fluxes of anions in protoplasts derived from wheat roots

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Abstract

An anion channel that only allows outward current flow (anion influx) has been identified in protoplasts derived from wheat (Triticum aestivum L., Triticum turgidum L.) roots. The anion outward rectifier (anion OR) measured by patch-clamp of whole cells activated very quickly, usually reaching a steady-state level in less than 100 ms and was easily distinguished from the cation outward rectifier (cation OR) which activated more slowly during membrane depolarisation. The anion OR is permeable to NO −3 and Cl−, moderately permeable to I−, and relatively impermeable to H2PO4/− and ClO4/−. An anomalous mole-fraction effect between ClO4/ − and Cl− was observed on the outward current, indicating that the channel is a multi-ion pore. The anion OR is gated by both voltage and external anion concentration such that it activates near to the equilibrium potential for the permeant anion. It activated at more negative membrane potentials when NO −3 was substituted for Cl− in the external medium, indicating that the channel may function to allow NO −3 influx under luxuriant external NO −3 concentrations. For most experiments, K+ and Cl− were the main cation and anion in solution, and under these conditions it appeared likely that the anion OR functioned in membrane-potential regulation by facilitating a Cl− influx at membrane potentials more positive than the chloride reversal potential (ECl). If ECl was more negative than the K+ reversal potential (EK) then the anion OR dominated but both the anion and cation ORs occurred together when the membrane potential difference (Vm) was positive of both ECl and EK. The cation OR was inhibited by increasing external Cl− concentrations, but the anion OR was not affected by external K+ or Na+ concentration. The anion-transport inhibitors, zinc and phenylglyoxal were ineffective in blocking the anion OR. 4,4′-Di-isothiocyanostilbene-2, 2′-disulfonic acid (DIDS) irreversibly blocked about 34% of the current when applied extracellularly at a concentration of 25 μM, and about 69% at a concentration of 200 μM. However, DIDS (200 μM) also occasionally acted as an irreversible blocker of the cation OR. Perchlorate blocked irreversibly 75% of the current at an external concentration of 10 mM and did not block the cation OR. Whole-cell currents also indicated that the anion OR was insensitive to external pH (pH=5–7) and calcium concentration ([Ca2+]=0.1–10 mM). Increasing intracellular calcium concentration significantly increased the occurrence of the fast outward current in whole cells (P < 0.005, X2 test). With approximately 10 nM calcium inside the cell the anion outward current was observed in 64% (n = 45) of cells and with 50 nM calcium inside the cell the anion current was observed in 88% (n = 69) of cells. Single-anion OR channels observed in outside-out patches had a conductance in 300 mM KCl (external) of about 4 pS. When voltage pulses were applied to outside-out patches the average currents were similar to those observed in whole cells. The significance of the anion OR as a likely route for Cl uptake in high salinities is discussed.

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Abbreviations

Bath:

solution bathing the extracellular face of the membrane

DIDS:

(4,4′-diisothiocyanostilbene-2,2′-disulfonic acid)

Ex :

reversal potential for ion x

OR:

outward rectifier

Pip :

solution inside the pipette

TEACl:

(tetraethyl-ammonium chloride)

Vm :

membrane potential difference

References

  • Binzel, M.L., Hess, D., Bressan, R.A., Hasegawa, P.M. (1988) Intracellular compartmentation of ions in salt adapted tobacco cells. Plant Physiol. 86, 607–614

    Google Scholar 

  • Blatt, M.R. (1988) Potassium-dependent, bipolar gating of K+ channels in guard cells. J. Membr. Biol. 102, 235–246

    Google Scholar 

  • Blatt, M.R. (1992) K+ channels of stomatal guard cells. J. Gen. Physiol. 99, 615–644

    Google Scholar 

  • Bretag, A.H. (1987) Muscle chloride channels. Physiol. Rev. 67, 618–724

    Google Scholar 

  • Cakirlar, H., Bowling, D.J.F. (1981) The effect of salinity of the membrane potential of sunflower roots. J. Exp. Bot. 32, 479–485

    Google Scholar 

  • Cerana, R., Colombo, R. (1992) K+ and Cl− conductance of Arabidopsis thaliana plasma membrane at depolarised voltages. Bot. Acta 105, 273–277

    Google Scholar 

  • Cheeseman, J.M., Hanson, J.B. (1979) Mathematical analysis of the dependence of cell potential on external potassium in corn roots. Plant Physiol. 63, 1–4

    Google Scholar 

  • Corey, D.P., Stevens, C.F. (1983) Science and technology of patchrecording electrodes. In: Single-channel recording, pp. 53–68, Sakmann, B., Neher, E., eds. Plenum Press, New York London

    Google Scholar 

  • Cosgrove, D.J., Hedrich, R. (1991) Stretch-activated chloride, potassium, and calcium channels coexisting in plasma membranes of guard cells of Vicia faba L. Planta 186, 143–153

    Google Scholar 

  • Coyaud, L., Kurkdjian, A., Kado, R., Hedrich, R. (1987) Ion channels and ATP-driven transport across the tonoplast of sugarbeet vacuoles. Biochim. Biophys. Acta. 902, 263–268

    Google Scholar 

  • Cram, W.J. (1973) Chloride fluxes in cells of the isolated root cortex of Zea mays. Aust. J. Biol. Sci. 26, 757–79

    Google Scholar 

  • Dhugga, K.S., Waines, J.G., Leonard, R.T. (1988) Nitrate absorption by corn roots. Plant Physiol. 86, 759–763

    Google Scholar 

  • Fairley, K., Laver, D., Walker, N.A. (1991) Whole-cell and single channel currents across the plasmalemma of corn shoot suspension cells. J. Membr. Biol. 121, 11–22

    Google Scholar 

  • Falke, L.C., Edwards, K.L., Pickard, B.G., Misler, S. (1988) A stretch-activated anion channel in tobacco protoplasts. FEBS Lett. 237, 141–144

    Google Scholar 

  • Findlay, G.P., Coleman, H.A. (1983) Potassium channels in the membrane of Hydrodictyon africanum. J. Membr. Biol. 75, 241–251

    Google Scholar 

  • Gradmann, D., Mayer, W.-E. (1977) Membrane potentials and ion permeabilities in flexor cells of the laminar pulvini of Phaseolus coccineus L. Planta 137, 19–24

    Google Scholar 

  • Hagiwara, S., Takahashi, K. (1974) Mechanism of anion permeation through the muscle fibre membrane of an elasmobranch fish, Taeniura lymma. J. Physiol. London 238, 109–127

    Google Scholar 

  • Hamill, O.P., Marty, A., Neher, E., Sakmann, B., Sigworth, F.J. (1981) Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pfluegers Arch. 391, 85–100

    Google Scholar 

  • Harris, E.J. (1958) Anion interaction in frog muscle. J. Physiol London 141, 351–365

    Google Scholar 

  • Hedrich, R., Kurkdjian, A. (1988) Characterisation of an anion-permeable channel from sugar beet vacuoles: effect of inhibitors. EMBO J. 7, 3661–3666

    Google Scholar 

  • Hedrich, R., Neher, E. (1987) Cytoplasmic calcium regulates voltage-dependent ion channels in plant vacuoles. Nature 329, 833–836

    Google Scholar 

  • Hedrich, R. Schroeder, J. (1989) The physiology of ion channels and electrogenic pumps in higher plants. Annu. Rev. Plant Physiol. 40, 539–69

    Google Scholar 

  • Hedrich, R., Busch, H., Raschke, K. (1990) Ca2+ and nucleotide dependent regulation of voltage dependent anion channels in the plasma membrane of guard cells. EMBO J. 9, 3889–3892

    Google Scholar 

  • Hille, B., Schwarz, W. (1978) Potassium channels as multi-ion singlefile pores. J. Gen Physiol. 72, 409–442

    Google Scholar 

  • Iijima, T., Hagiwara, S. (1987) Voltage-dependent K channels in protoplasts of trap-lobe cells of Dionaea muscipula. J. Membr. Biol. 100, 73–81

    Google Scholar 

  • Keifer, D.W., Franceschi, V.R., Lucas, W.J. (1982) Plasmalemma chloride transport in Chara corallina. Inhibition by 4,4′-diisothiocyano-2–2′disulfonic acid stilbene. Plant Physiol. 70, 1327–1334

    Google Scholar 

  • Keller, B.U., Hedrich, R., Raschke (1989) Voltage-dependent anion channels in the plasma membrane of guard cells. Nature 341, 450–453

    Google Scholar 

  • Ketchum, K.A., Poole, R.J. (1991) Cytosolic calcium regulates a potassium current in corn (Zea mays) protoplasts. J. Membr. Biol. 119, 277–288

    Google Scholar 

  • Kingsbury, R.W, Epstein, E. (1986) Salt sensitivity in wheat. Plant Physiol. 80, 651–654

    Google Scholar 

  • Kochian, L.V., Xin-Zhi, J., Lucas, W.J. (1985) Potassium transport in corn roots: IV. Characterisation of the linear component. Plant Physiol. 79, 771–776

    Google Scholar 

  • Kourie, J.I., Findlay, G.P. (1990) Ionic currents across the plasmalella of Chara inflata cells. J. Exp. Bot. 41, 151–163

    Google Scholar 

  • Lew, R.R. (1991) Substrate regulation of single potassium and chloride channels in Arabidopsis plasma membrane. Plant Physiol. 95, 642–647

    Google Scholar 

  • Lin, W. (1980) Corn root protoplasts: isolation and general characterisation of ion transport. Plant Physiol. 66, 550–554

    Google Scholar 

  • Lynch, J., Polito, V.S., Lauchli, A. (1989) Salinity stress increases cytoplasmic Ca activity in maize root protoplasts. Plant Physiol. 90, 1271–1274

    Google Scholar 

  • Marten, L, Busch, H., Raschke, K., Hedrich, R. (1993) Modulation and block of the plasma membrane anion channel of guard cells by stilbene derivatives. Eur. Biophys. J. 21, 403–408

    Google Scholar 

  • Marten, I., Zeiilinger, C., Redhead, C., Landry, D.W., Al-Awqati, Q., Hedrich, R. (1992) Identification and modulation of a voltagedependent anion channel in the plasma membrane of guard cells by high-affinity ligands. EMBO Journal 11, 3569–3575

    Google Scholar 

  • Pantoja, O., Dainty, J., Blumwald, E. (1992) Cytoplasmic chloride regulates cation channels in the vacuolar membrane of plant cells. J. Membr. Biol. 125, 219–229

    Google Scholar 

  • Schachtman, D.P., Tyerman, S.D., Terry, B.R. (1991) The K+/Na+ selectivity of a cation channel in the plasma membrane of root cells does not differ in salt-tolerant and salt-sensitive wheat species. Plant Physiol. 97, 598–605

    Google Scholar 

  • Schauf, C.L., Wilson, K.J. (1987) Properties of single K+ and Cl− channels in Asclepias tuberosa protoplasts. Plant Physiol. 85, 413–418

    Google Scholar 

  • Schroeder, J.I. (1989) Quantitative analysis of outward rectifying K+ channel currents in guard cell protoplasts from Vicia faba. J. Membr. Biol. 107, 229–235

    Google Scholar 

  • Schroeder, J.I., Hagiwara, S. (1989) Cytosolic calcium regulates ion channels in the plasma membrane of Vicia faba guard cells. Nature 338, 427–430

    Google Scholar 

  • Schroeder, J.I., Keller, B.U. (1992) Two types of anion channel currents in guard cells with distinct voltage regulation. Proc. Natl. Acad. Sci. 89, 5025–5029

    Google Scholar 

  • Schroeder, J.I., Raschke, K., Neher, E. (1987) Voltage dependence of K+ channels in guard cell protoplasts. Proc. Natl. Acad. Sci. 84, 4108–4112

    Google Scholar 

  • Siddiqi, M.Y., Glass, A.D.M., Ruth, T.J., Rufty, T.W. Jr. (1990) Studies of uptake of nitrate in barley I. Kinetics of 13NO −3 Influx. Plant Physiol. 93, 1426–1432

    Google Scholar 

  • Terry, B.R., Tyerman, S.D., Findlay, G.P. (1991) Ion channels in the plasma membrane of Amaranthus protoplasts: one cation and one anion channel dominate the conductance. J. Membr. Biol. 121, 223–236

    Google Scholar 

  • Terry, B.R., Findlay, G.P., Tyerman, S.D. (1992a) Direct effects of Ca2+-channel blockers on plasma membrane cation channels of Amaranthus tricolor protoplasts. J. Exp. Bot. 43, 1457–1473

    Google Scholar 

  • Terry, B.R., Tyerman, S.D., Findlay, G.P. (1992b) Ion channels in the plasma membrane of plant cells. In: Swelling mechanics: From clays to whole organisms (NATO ASI Ser.), pp. 225–236, T.K. Karalis, ed. Elsevier, Amsterdam

    Google Scholar 

  • Tester, M. (1988) Potassium channels in the plasmalemma of Chara corallina are multi-ion pores: voltage-dependent blockade by Cs+ and anomalous permeabilities. J. Membr. Biol. 105, 87–94

    Google Scholar 

  • Tester, M. (1990) Plant ion channels: whole-cell and single channels studies. New Phytol. 114, 305–40

    Google Scholar 

  • Tyerman, S.D. (1992) Anion channels in plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 43, 351–373

    Google Scholar 

  • Tyerman, S.D., Findlay, G.P., Patterson, G.J. (1986) Inward membrane current in Chara inflata: I. A voltage- and time-dependent Cl− component. J. Membr. Biol. 89, 139–152

    Google Scholar 

  • Tyerman, S.D., Schachtman, D.P. (1992) The role of ion channels in plant nutrition and prospects for their genetic manipulation. Plant Soil 146, 137–144

    Google Scholar 

  • Tyerman, S.D., Oats, P., Gibbs, J., Dracup, M., Greenway, H. (1989) Turgor-volume regulation and cellular water relations in Nicotiana tabacum roots grown in high salinities. Aust. J. Plant Physiol. 16, 517–31

    Google Scholar 

  • Walker, N.A. (1981) The transport systems of charophyte and chlorophyte giant algae and their integration into modes of behaviour. In: Plant membrane transport: current conceptual issues, pp. 287–300, R.M. Spanswick, W.J. Lucas, J. Dainty eds. Elsevier, Amsterdam

    Google Scholar 

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Authors and Affiliations

  1. School of Biological Sciences, The Flinders University of South Australia, GPO Box 2100, 5001, Adelaide, SA, Australia

    M. Skerrett & S. D. Tyerman

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  1. M. Skerrett
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  2. S. D. Tyerman
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Additional information

We thank the Australian Research Council for financial support, G.P. Findlay and A. Garrill for helpful discussions, and K. Morris and D. Mackenzie for expert technical assistance. M.S. was supported by an Australian Postgraduate Research Award.

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Skerrett, M., Tyerman, S.D. A channel that allows inwardly directed fluxes of anions in protoplasts derived from wheat roots. Planta 192, 295–305 (1994). https://doi.org/10.1007/BF00198563

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