Molecular Plant Biology Unit, Department of Biochemistry, University of Turku, Turku, Finland.
Laboratory for Genome Engineering & Synthetic Biology, Division of Biological Sciences & Center for Desert Agriculture, 4700 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Plant Signal Behav. 2021 May 4;16(5):1885165. doi: 10.1080/15592324.2021.1885165. Epub 2021 Mar 8.
Abscisic acid (ABA) is an important phytohormone mediating osmotic stress responses. SUCROSE NONFERMENTING 1 (SNF1)-RELATED PROTEIN KINASE 2.6 (SnRK2.6, also named OPEN STOMATA1 and SNF1-RELATED KINASE 2E) is central in the ABA signaling pathway; therefore, manipulating its activity may be useful to confer stress tolerance in plants. Pladienolide B (PB) is an mRNA splicing inhibitor and enhances ABA responses. Here, we analyzed the effect of PB on SnRK2.6. PB enhanced the activity of recombinant SnRK2.6 through direct physical interaction as predicted by molecular docking simulations followed by mutation experiments and isothermal titration calorimetry. Structural modeling predicted probable interaction sites between PB and SnRK2.6, and experiments with mutated SnRK2.6 revealed that Leu-46 was the most essential amino acid residue for SnRK2.6 activation by PB. This study demonstrates the feasibility of SnRK2.6 chemical manipulation and paves the way for the modification of plant osmotic stress responses.
脱落酸（ABA）是一种重要的植物激素，介导渗透胁迫反应。蔗糖非发酵 1（SNF1）相关蛋白激酶 2.6（SnRK2.6，也称为 OPEN STOMATA1 和 SNF1-RELATED KINASE 2E）是 ABA 信号通路的核心；因此，操纵其活性可能有助于赋予植物对胁迫的耐受性。Pladienolide B（PB）是一种 mRNA 剪接抑制剂，可增强 ABA 反应。在这里，我们分析了 PB 对 SnRK2.6 的影响。PB 通过分子对接模拟预测的直接物理相互作用增强了重组 SnRK2.6 的活性，随后进行了突变实验和等温热滴定实验。结构建模预测了 PB 和 SnRK2.6 之间可能的相互作用位点，而突变 SnRK2.6 的实验表明，Leu-46 是 PB 激活 SnRK2.6 的最关键氨基酸残基。这项研究证明了 SnRK2.6 化学操作的可行性，并为修饰植物渗透胁迫反应铺平了道路。
