TY - JOUR
T1 - Arabidopsis root K+-efflux conductance activated by hydroxyl radicals
T2 - Single-channel properties, genetic basis and involvement in stress-induced cell death
AU - Demidchik, Vadim
AU - Cuin, Tracey A.
AU - Svistunenko, Dimitri
AU - Smith, Susan J.
AU - Miller, Anthony J.
AU - Shabala, Sergey
AU - Sokolik, Anatoliy
AU - Yurin, Vladimir
PY - 2010/5/1
Y1 - 2010/5/1
N2 - 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 Ca2+, tetraethylammonium, Ba2+, 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.
AB - 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 Ca2+, tetraethylammonium, Ba2+, 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.
KW - Ion channels
KW - Plant
KW - Potassium
KW - Programmed cell death
KW - Reactive oxygen species
KW - Stress
UR - http://www.scopus.com/inward/record.url?scp=77951754328&partnerID=8YFLogxK
U2 - 10.1242/jcs.064352
DO - 10.1242/jcs.064352
M3 - Article
C2 - 20375061
AN - SCOPUS:77951754328
SN - 0021-9533
VL - 123
SP - 1468
EP - 1479
JO - Journal of Cell Science
JF - Journal of Cell Science
IS - 9
ER -