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
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
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DOI：
10.1104/pp.104.046573
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发表时间：
2004-03
期刊：
影响因子：
7.4
通讯作者：
Xiao Zhang;Hengbin Wang;A. Takemiya;Chunpeng Song;T. Kinoshita;K. Shimazaki
中科院分区：
文献类型：
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作者：
Xiao Zhang;Hengbin Wang;A. Takemiya;Chunpeng Song;T. Kinoshita;K. Shimazaki
脱落酸（阿坝）抑制保卫细胞依赖蓝光（BL）的H+泵送，从而驱动气孔开放。我们研究了这种反应与质膜H+-ATP酶的活性使用蚕豆保卫细胞原生质体。10 μm浓度的阿坝抑制BL刺激的质膜H ~+-ATPase的ATP水解、H ~+-ATPase的磷酸化以及14-3-3蛋白与H ~+-ATPase的结合。所有这些反应同样抑制过氧化氢（H2 O2）在1毫米。ABA诱导的抑制BL-依赖的H+泵和磷酸化的H+-ATP酶部分恢复抗坏血酸，细胞内H2 O2清除剂。用2′，7 ′-二氯荧光素对胞质H2 O2进行单细胞分析，结果表明保卫细胞原生质体中的H2 O2是由阿坝产生的。阿坝和H_2O_2对褐孢菌素诱导的H ~+泵和14-3-3蛋白与H ~+-ATPase的结合有轻微的抑制作用（约20%）。相比之下，H2 O2在1毫米没有影响H+泵的微粒体膜中的H+-ATP酶。从这些结果中，我们得出结论，由阿坝抑制BL依赖的H+泵是由于H+-ATP酶的磷酸化水平的降低，H2 O2可能参与了这一反应。此外，在保卫细胞BL信号通路中，阿坝至少存在两个抑制位点。
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.