The Antagonistic Action of Abscisic Acid and Cytokinin Signaling Mediates Drought Stress Response in Arabidopsis
The Antagonistic Action of Abscisic Acid and Cytokinin Signaling Mediates Drought Stress Response in Arabidopsis
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脱落酸和细胞分裂素信号传导的拮抗作用介导拟南芥的干旱应激反应
DOI：
10.1016/j.molp.2018.05.001
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发表时间：
2018-07-02
期刊：
影响因子：
27.5
通讯作者：
Shi, Yiting
中科院分区：
文献类型：
--
作者：
Huang, Xiaozhen;Hou, Lingyan;Shi, Yiting
作为固着生物，植物面临各种环境胁迫，必须优化其生长以生存。脱落酸（ABA）和细胞分裂素拮抗调节植物的许多发育过程和环境胁迫反应。然而，这种拮抗作用的分子机制仍然不清楚。在这项研究中，我们证明了蔗糖非发酵1相关激酶SnRK2.2，SnRK2.3和SnRK2.6，ABA信号通路的关键激酶，直接相互作用和磷酸化A型反应调节因子5（ARR5），细胞分裂素信号的负调节。SnRK2s对ARR5丝氨酸残基的磷酸化增强了ARR5蛋白的稳定性。因此，过表达ARR5的植物表现出ABA超敏性和耐旱性，并且这些表型不能通过过表达非磷酸化的ARR5模拟物来重现。此外，B型ARR，ARR1，ARR11和ARR12，物理上与SnRK2s相互作用并抑制SnRK2.6的激酶活性。arr1、11、12三突变体对ABA表现出高度的敏感性。遗传分析表明，SnRK2在ARR5的上游，ARR1，ARR11和ARR12的下游起作用，介导ABA反应和耐旱性。综上所述，本研究揭示了ABA和细胞分裂素信号通路中几个分子组分在介导干旱胁迫反应中的拮抗作用，为植物如何通过整合多种激素途径协调生长和干旱胁迫反应提供了重要的见解。
As sessile organisms, plants encounter a variety of environmental stresses and must optimize their growth for survival. Abscisic acid (ABA) and cytokinin antagonistically regulate many developmental processes and environmental stress responses in plants. However, the molecular mechanism underlying this antagonism remains poorly defined. In this study, we demonstrated that Sucrose nonfermenting1-related kinases SnRK2.2, SnRK2.3, and SnRK2.6, the key kinases of the ABA signaling pathway, directly interact with and phosphorylate type-A response regulator 5 (ARR5), a negative regulator of cytokinin signaling. The phosphorylation of ARR5 Ser residues by SnRK2s enhanced ARR5 protein stability. Accordingly, plants overexpressing ARR5 showed ABA hypersensitivity and drought tolerance, and these phenotypes could not be recapitulated by overexpressing a non-phosphorylated ARR5 mimic. Moreover, the type-B ARRs, ARR1, ARR11 and ARR12, physically interacted with SnRK2s and repressed the kinase activity of SnRK2.6. The arr1,11,12 triple mutant exhibited hypersensitivity to ABA. Genetic analysis demonstrated that SnRK2s act upstream of ARR5 but downstream of ARR1, ARR11 and ARR12 in mediating ABA response and drought tolerance. Taken together, this study unravels the antagonistic actions of several molecular components of the ABA and cytokinin signaling pathways in mediates drought stress response, providing significant insights into how plants coordinate growth and drought stress response by integrating multiple hormone pathways.