Ozone-triggered rapid stomatal response involves the production of reactive oxygen species, and is controlled by SLAC1 and OST1.
Ozone-triggered rapid stomatal response involves the production of reactive oxygen species, and is controlled by SLAC1 and OST1.
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DOI：
10.1111/j.1365-313x.2010.04159.x
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
Triin Vahisalu;Irina Puzõrjova;M. Brosché;Ervin Valk;M. Lepiku;H. Moldau;P. Pechter;Yuh-Shuh Wang-
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文献类型：
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作者：
Triin Vahisalu;Irina Puzõrjova;M. Brosché;Ervin Valk;M. Lepiku;H. Moldau;P. Pechter;Yuh-Shuh Wang-
空气污染物臭氧可用作分解活性氧 (ROS) 引起的植物过程的工具。在这里，我们利用臭氧来研究 ROS 依赖性气孔信号传导。我们发现，臭氧引发的气孔导度快速瞬时下降（RTD）与保卫细胞中活性氧的爆发同时发生。 RTD 存在于 11 种不同的拟南芥生态型中，表明这是一种遗传上稳健的反应。为了研究哪些信号成分或离子通道参与 RTD，我们测试了 44 个在气孔功能各个方面存在缺陷的突变体。这表明，保卫细胞质膜 S 型阴离子通道功能所必需的 SLAC1 蛋白和蛋白激酶 OST1 是 ROS 诱导的快速气孔关闭所必需的。我们展示了 OST1 和 SLAC1 之间的物理相互作用，并提供了 SLAC1 被 OST1 磷酸化的证据。磷酸化蛋白质组学实验表明，OST1 磷酸化 SLAC1 N 末端的多个氨基酸。使用 TILLING，我们鉴定了三个新的 slac1 等位基因，其中预测的磷酸位点发生了突变。其中两个 slac1-7 (S120F) 和 slac1-8 (S146F) 缺乏 RTD，表明这些丝氨酸残基对于 SLAC1 的激活很重要。然而，质谱分析结合定点诱变和磷酸化测定表明，只有 S120 是 OST1 的特定磷酸化位点。显性失活突变体 abi1-1 和 abi2-1 中 RTD 的缺失也表明蛋白磷酸酶 ABI1 和 ABI2 在 ROS 诱导的 S 型阴离子通道激活中具有调节作用。
The air pollutant ozone can be used as a tool to unravel in planta processes induced by reactive oxygen species (ROS). Here, we have utilized ozone to study ROS-dependent stomatal signaling. We show that the ozone-triggered rapid transient decrease (RTD) in stomatal conductance coincided with a burst of ROS in guard cells. RTD was present in 11 different Arabidopsis ecotypes, suggesting that it is a genetically robust response. To study which signaling components or ion channels were involved in RTD, we tested 44 mutants deficient in various aspects of stomatal function. This revealed that the SLAC1 protein, essential for guard cell plasma membrane S-type anion channel function, and the protein kinase OST1 were required for the ROS-induced fast stomatal closure. We showed a physical interaction between OST1 and SLAC1, and provide evidence that SLAC1 is phosphorylated by OST1. Phosphoproteomic experiments indicated that OST1 phosphorylated multiple amino acids in the N terminus of SLAC1. Using TILLING we identified three new slac1 alleles where predicted phosphosites were mutated. The lack of RTD in two of them, slac1-7 (S120F) and slac1-8 (S146F), suggested that these serine residues were important for the activation of SLAC1. Mass-spectrometry analysis combined with site-directed mutagenesis and phosphorylation assays, however, showed that only S120 was a specific phosphorylation site for OST1. The absence of the RTD in the dominant-negative mutants abi1-1 and abi2-1 also suggested a regulatory role for the protein phosphatases ABI1 and ABI2 in the ROS-induced activation of the S-type anion channel.