Arabidopsis RZFP34/CHYR1, a Ubiquitin E3 Ligase, Regulates Stomatal Movement and Drought Tolerance via SnRK2.6-Mediated Phosphorylation
Arabidopsis RZFP34/CHYR1, a Ubiquitin E3 Ligase, Regulates Stomatal Movement and Drought Tolerance via SnRK2.6-Mediated Phosphorylation
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拟南芥 RZFP34/CHYR1 是一种泛素 E3 连接酶，通过 SnRK2.6 介导的磷酸化调节气孔运动和耐旱性
DOI：
10.1105/tpc.15.00321
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发表时间：
2015-11-01
期刊：
影响因子：
11.6
通讯作者：
Qin, Feng
中科院分区：
文献类型：
--
作者：
Ding, Shuangcheng;Zhang, Bin;Qin, Feng
脱落酸（阿坝）是一种植物激素，在植物生长发育和逆境响应中起着重要作用，尤其是在调节气孔关闭以响应水分亏缺胁迫中。响应阿坝和干旱胁迫的信号转导是由蛋白磷酸化和泛素化介导的。这项研究鉴定了拟南芥环锌指蛋白34（RZP 34;在此重新命名为CHY ZINC-FINGER AND RING PROTEIN 1 [CHYR 1]）作为泛素E3连接酶。CHYR 1的表达受到阿坝和干旱的显着诱导，并沿着其相应蛋白主要在维管组织和气孔中表达。对CHYR 1功能获得和功能丧失植物的分析表明，CHYR 1促进ABA诱导的气孔关闭、活性氧产生和植物耐旱性。此外，CHYR 1与SNF 1相关蛋白激酶2（SnRK 2）激酶相互作用，并可被SnRK2.6在Thr-178残基上磷酸化。磷酸化缺陷突变体CHYR 1（T178 A）的过表达干扰了CHYR 1的正常功能，而CHYR 1（T178 D）表型模仿了CHYR 1功能的获得。因此，本研究确定了RING型泛素E3连接酶，在阿坝和干旱反应中发挥积极作用，并详细说明了其泛素E3连接酶活性是如何通过SnRK2.6介导的蛋白磷酸化调节的。
Abscisic acid (ABA) is a phytohormone that plays a fundamental role in plant development and stress response, especially in the regulation of stomatal closure in response to water deficit stress. The signal transduction that occurs in response to ABA and drought stress is mediated by protein phosphorylation and ubiquitination. This research identified Arabidopsis thaliana RING ZINC-FINGER PROTEIN34 (RZP34; renamed here as CHY ZINC-FINGER AND RING PROTEIN1 [CHYR1]) as an ubiquitin E3 ligase. CHYR1 expression was significantly induced by ABA and drought, and along with its corresponding protein, was expressed mainly in vascular tissues and stomata. Analysis of CHYR1 gain-of-function and loss-of-function plants revealed that CHYR1 promotes ABA-induced stomatal closure, reactive oxygen species production, and plant drought tolerance. Furthermore, CHYR1 interacted with SNF1-RELATED PROTEIN KINASE2 (SnRK2) kinases and could be phosphorylated by SnRK2.6 on the Thr-178 residue. Overexpression of CHYR1(T178A), a phosphorylation-deficient mutant, interfered with the proper function of CHYR1, whereas CHYR1(T178D) phenocopied the gain of function of CHYR1. Thus, this study identified a RING-type ubiquitin E3 ligase that functions positively in ABA and drought responses and detailed how its ubiquitin E3 ligase activity is regulated by SnRK2.6-mediated protein phosphorylation.