Inhibition of Blue Light-Dependent H+ Pumping by Abscisic Acid through Hydrogen Peroxide-Induced Dephosphorylation of the Plasma Membrane H+-ATPase in Guard Cell Protoplasts1
AUTOR(ES)
Zhang, Xiao
FONTE
American Society of Plant Biologists
RESUMO
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 H2O2 scavenger. 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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=535845Documentos Relacionados
- Inhibition of Blue Light-Dependent H+ Pumping by Abscisic Acid in Vicia Guard-Cell Protoplasts.
- Plant Defense Response to Fungal Pathogens (Activation of Host-Plasma Membrane H+-ATPase by Elicitor-Induced Enzyme Dephosphorylation).
- H+-ATPase Activity from Storage Tissue of Beta vulgaris1: IV. N,N′-Dicyclohexylcarbodiimide Binding and Inhibition of the Plasma Membrane H+-ATPase
- Light-Dependent Reduction of Hydrogen Peroxide by Ruptured Pea Chloroplasts 1
- Plasma Membrane H+-ATPase in Maize Roots Induced for NO3- Uptake.