Crosstalk between blue-light- and aba-signaling pathways in stomatal guard cells

Abstract

We recently established an immunohistochemical method for the detection of blue light (BL)-induced and phototropin-mediated phosphorylation of plasma-membrane H +-ATPase in stomatal guard cells of Arabidopsis thaliana. This technique makes it possible to detect the phosphorylation/activation status of guard-cell H +-ATPase in the epidermis of a single rosette leaf, without the need to prepare guard-cell protoplasts (GCPs) from a large number of plants. Moreover, it can detect guard-cell responses under more natural and stress-free conditions compared with using GCPs. Taking advantage of these properties, we examined the effect of abscisic acid (ABA) on BL-induced phosphorylation of guard-cell H +-ATPase by using ABA-insensitive mutants. This revealed inhibition of BL-induced phosphorylation of guard-cell H +-ATPase via the early ABA-signaling components PYR/PYL/RCAR-PP2Cs-SnRK2s, which are known to be early ABA-signaling components for a wide range of ABA responses in plants. © 2011 Landes Bioscience.