PYR/PYL/RCAR abscisic acid receptors regulate K+ and Cl- channels through reactive oxygen species-mediated activation of Ca2+ channels at the plasma membrane of intact Arabidopsis guard cells.

Wang, Y., Chen, Z., Zhang, B. , Hills, A. and Blatt, M. R. (2013) PYR/PYL/RCAR abscisic acid receptors regulate K+ and Cl- channels through reactive oxygen species-mediated activation of Ca2+ channels at the plasma membrane of intact Arabidopsis guard cells. Plant Physiology, 163(2), pp. 566-577. (doi:10.​1104/​pp.​113.​219758)

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Publisher's URL: http:/​/​dx.​doi.​org/​10.​1104/​pp.​113.​219758

Abstract

The discovery of the START family of abscisic acid (ABA) receptors places these proteins at the front of a protein kinase/phosphatase signal cascade that promotes stomatal closure. The connection of these receptors to Ca2+ signals evoked by ABA has proven more difficult to resolve, although it has been implicated by studies of the pyrbactin-insensitive pyr1/pyl1/pyl2/pyl4 quadruple mutant. One difficulty is that flux through plasma membrane Ca2+ channels and Ca2+ release from endomembrane stores coordinately elevate cytosolic free Ca2+ concentration ([Ca2+]i) in guard cells, and both processes are facilitated by ABA. Here, we describe a method for recording Ca2+ channels at the plasma membrane of intact guard cells of Arabidopsis (Arabidopsis thaliana). We have used this method to resolve the loss of ABA-evoked Ca2+ channel activity at the plasma membrane in the pyr1/pyl1/pyl2/pyl4 mutant and show the consequent suppression of [Ca2+]i increases in vivo. The basal activity of Ca2+ channels was not affected in the mutant; raising the concentration of Ca2+ outside was sufficient to promote Ca2+ entry, to inactivate current carried by inward-rectifying K+ channels and to activate current carried by the anion channels, both of which are sensitive to [Ca2+]i elevations. However, the ABA-dependent increase in reactive oxygen species (ROS) was impaired. Adding the ROS hydrogen peroxide was sufficient to activate the Ca2+ channels and trigger stomatal closure in the mutant. These results offer direct evidence of PYR/PYL/RCAR receptor coupling to the activation by ABA of plasma membrane Ca2+ channels through ROS, thus affecting [Ca2+]i and its regulation of stomatal closure.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hills, Mr Adrian and Blatt, Professor Michael and Zhang, Dr Ben and Chen, Dr Zhonghua and Wang, Dr Yizhou
Authors: Wang, Y., Chen, Z., Zhang, B., Hills, A., and Blatt, M. R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Plant Physiology
Publisher:American Society of Plant Biologists
ISSN:0032-0889
ISSN (Online):1532-2548
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in Plant Physiology 163(2):566-577
Publisher Policy:Reproduced under a Creative Commons License
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
616991Directed control of secretory vesicle fusionMichael BlattBiotechnology and Biological Sciences Research Council (BBSRC)BB/K015893/1RI MOLECULAR CELL & SYSTEMS BIOLOGY