ABA, H2O2 and the BL signaling pathway of stomata

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Inhibition of blue light-dependent H+ pumping by abscisic acid through hydrogen peroxide-induced dephosphorylation of the plasma membrane H+-ATPase in guard cell protoplasts

by Zhang X., Wang H. B., Takemiya A., Song C .P., Kinoshita T., Shimazaki K. I. (2004)

Xiao ZhangHengbin WangAtsushi TakemiyaChun-peng SongToshinori KinoshitaKen-ichiro Shimazaki

in Plant Physiol, 136 (2004), pp. 4150–4158. – DOI: https://doi.org/10.1104/pp.104.046573

Abstract/FREE Full Text – CrossRefPubMedCAS |-



Blue light (BL)-dependent H+ pumping by guard cells, which drives stomatal opening, is inhibited by abscisic acid (ABA).

We investigated this response with respect to the activity of plasma membrane H+-ATPase using Vicia guard cell protoplasts. ATP hydrolysis by the plasma membrane H+-ATPase, phosphorylation of the H+-ATPase, and the binding of 14-3-3 protein to the H+-ATPase stimulated by BL were inhibited by ABA at 10 μm.

All of these responses were similarly inhibited by hydrogen peroxide (H2O2) at 1 mm. The ABA-induced inhibitions of BL-dependent H+ pumping and phosphorylation of the H+-ATPase were partially restored by ascorbate, an intracellular H2O2scavenger. A single-cell analysis of the cytosolic H2O2 using 2′,7′-dichlorofluorescin revealed that H2O2 was generated by ABA in guard cell protoplasts.

We also indicated that H+ pumping induced by fusicoccin and the binding of 14-3-3 protein to the H+-ATPase were inhibited slightly (approximately 20%) by both ABA and H2O2. By contrast, H2O2 at 1 mm did not affect H+ pumping by the H+-ATPase in microsomal membranes.

From these results, we concluded that inhibition of BL-dependent H+ pumping by ABA was due to a decrease in the phosphorylation levels of H+-ATPase and that H2O2 might be involved in this response. Moreover, there are at least two inhibition sites by ABA in the BL signaling pathway of guard cells.


Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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