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Arabidopsis root K<sup>+</sup>-efflux conductance activated by hydroxyl radicals: Single-channel properties, genetic basis and involvement in stress-induced cell death

Demidchik, V and Cuin, TA and Svistunenko, D and Smith, SJ and Miller, AJ and Shabala, S and Sokolik, A and Yurin, V (2010) 'Arabidopsis root K<sup>+</sup>-efflux conductance activated by hydroxyl radicals: Single-channel properties, genetic basis and involvement in stress-induced cell death.' Journal of Cell Science, 123 (9). 1468 - 1479. ISSN 0021-9533

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Abstract

Reactive oxygen species (ROS) are central to plant stress response, signalling, development and a multitude of other processes. In this study, the plasma-membrane hydroxyl radical (HR)-activated K + channel responsible for K+ efflux from root cells during stress accompanied by ROS generation is characterised. The channel showed 16-pS unitary conductance and was sensitive to Ca 2+ , tetraethylammonium, Ba 2+ , Cs + and free-radical scavengers. The channel was not found in the gork1-1 mutant, which lacks a major plasma-membrane outwardly rectifying K + channel. In intact Arabidopsis roots, both HRs and stress induced a dramatic K + efflux that was much smaller in gork1-1 plants. Tests with electron paramagnetic resonance spectroscopy showed that NaCl can stimulate HR generation in roots and this might lead to K + -channel activation. In animals, activation of K + -efflux channels by HRs can trigger programmed cell death (PCD). PCD symptoms in Arabidopsis roots developed much more slowly in gork1-1 and wild-type plants treated with K + -channel blockers or HR scavengers. Therefore, similar to animal counterparts, plant HR-activated K + channels are also involved in PCD. Overall, this study provides new insight into the regulation of plant cation transport by ROS and demonstrates possible physiological properties of plant HR-activated K + channels.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Depositing User: Jim Jamieson
Date Deposited: 23 Sep 2011 09:02
Last Modified: 20 Sep 2017 07:15
URI: http://repository.essex.ac.uk/id/eprint/984

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