Polyamines interact with hydroxyl radicals in activating Ca2+ and k+ transport across the root epidermal plasma membranes

Isaac Zepeda-Jazo, Ana María Velarde-Buendía, René Enríquez-Figueroa, Jayakumar Bose, Sergey Shabala, Jesús Muñiz-Murguía, Igor I. Pottosin

Research output: Contribution to journalArticlepeer-review

133 Citations (Scopus)


Reactive oxygen species (ROS) are integral components of the plant adaptive responses to environment. Importantly, ROS affect the intracellular Ca2+ dynamics by activating a range of nonselective Ca2+-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 Ca2+ fluxes induced by hydroxyl radicals (OH) in pea (Pisum sativum) roots. OH, but not hydrogen peroxide, activated a rapid Ca2+ efflux and a more slowly developing net Ca2+ 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 Ca2+. Active OH-induced Ca2+ efflux in roots was suppressed by the PMCa2+ 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 Ca2+ influx in roots. Contrary to expectations, polyamines (PAs) did not inhibit the OH-induced cation fluxes. The net OH-induced Ca2+ 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 Ca2+ homeostasis by modulating both Ca2+ influx and efflux transport systems at the root cell PM.

Original languageEnglish
Pages (from-to)2167-2180
Number of pages14
JournalPlant Physiology
Issue number4
Publication statusPublished - Dec 2011
Externally publishedYes


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