University Of Tasmania

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Polyamines cause plasma membrane depolarization, activate Ca2+-, and modulate H+-ATPase pump activity in pea roots

journal contribution
posted on 2023-05-18, 01:59 authored by Igor Pottosin, Velarde-Buendia, AM, Bose, J, Fuglsang, AT, Sergey ShabalaSergey Shabala
Polyamines regulate a variety of cation and K+ channels, but their potential effects on cation-transporting ATPases are underexplored. In this work, noninvasive microelectrode ion flux estimation and conventional microelectrode techniques were applied to study the effects of polyamines on Ca2+ and H+ transport and membrane potential in pea roots. Externally applied spermine or putrescine (1mM) equally activated eosin yellow (EY)-sensitive Ca2+ pumping across the root epidermis and caused net H+ influx or efflux. Proton influx induced by spermine was suppressed by EY, supporting the mechanism in which Ca2+ pump imports 2 H+ per each exported Ca2+. Suppression of the Ca2+ pump by EY diminished putrescine-induced net H+ efflux instead of increasing it. Thus, activities of Ca2+ and H+ pumps were coupled, likely due to the H+-pump inhibition by intracellular Ca2+. Additionally, spermine but not putrescine caused a direct inhibition of H+ pumping in isolated plasma membrane vesicles. Spermine, spermidine, and putrescine (1mM) induced membrane depolarization by 70, 50, and 35 mV, respectively. Spermine-induced depolarization was abolished by cation transport blocker Gd3+, was insensitive to anion channels’ blocker niflumate, and was dependent on external Ca2+. Further analysis showed that uptake of polyamines but not polyamine-induced cationic (K++Ca2++H+) fluxes were a main cause of membrane depolarization. Polyamine increase is a common component of plant stress responses. Activation of Ca2+ efflux by polyamines and contrasting effects of polyamines on net H+ fluxes and membrane potential can contribute to Ca2+ signalling and modulate a variety of transport processes across the plasma membrane under stress.


Publication title

Journal of Experimental Botany










Tasmanian Institute of Agriculture (TIA)


Oxford Univ Press

Place of publication

Great Clarendon St, Oxford, England, Ox2 6Dp

Rights statement

Copyright 2014 The Author

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the biological sciences