Pepper E3 ligase CaAIRE1 promotes ABA sensitivity and drought tolerance by degradation of protein phosphatase CaAITP1
Pepper E3 ligase CaAIRE1 promotes ABA sensitivity and drought tolerance by degradation of protein phosphatase CaAITP1
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DOI：
10.1093/jxb/erab138
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发表时间：
2021-04-10
影响因子：
6.9
通讯作者：
Lee, Sung Chul
中科院分区：
文献类型：
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作者：
Baek, Woonhee;Lim, Chae Woo;Lee, Sung Chul
植物已经发展出在极端环境条件下生存的防御机制。脱落酸(ABA)是植物适应环境胁迫的重要激素。在本研究中，我们分离并鉴定了含有C3HC4型环结构域的辣椒环型E3连接酶CaAIRE1(Capsicum annuum ABA Induced Ring-type E3 Ligase 1)。CaAIRE1受ABA和干旱诱导，CaAIRE1具有E3连接酶活性。CaAIRE1沉默的辣椒和CaAIRE1过表达的拟南芥分别表现出对干旱敏感和耐旱的表型，并伴随着蒸腾失水和ABA敏感性的变化。此外，我们还发现CaAIRE1与辣椒2C蛋白磷酸酶CaAITP1(辣椒CaAIRE1相互作用靶标磷酸酶1)相互作用并使其泛素化。对CaAIRE1沉默的辣椒和CaAIRE1过表达的拟南芥植株进行的无细胞降解实验表明，CaAITP1蛋白水平受到CaAIRE1表达水平的负调控。与CaAIRE1相比，CaAITP1沉默的辣椒表现出对ABA敏感的表型。与野生型和其他辣椒PP2C高表达植株相比，CaAITP1高表达拟南芥是对ABA最不敏感的表型。综上所述，我们的研究结果表明，CaAITP1在ABA信号转导中起主要的负调控作用，CaAIRE1通过调节CaAITP1的稳定性来调节ABA信号和干旱反应。
Plants have developed defense mechanisms to survive in extreme environmental conditions. Abscisic acid (ABA) is a key phytohormone associated with plant adaptation to environmental stress. In this study, we isolated and functionally characterized the pepper RING-type E3 ligase CaAIRE1 (Capsicum annuum ABA Induced RING-type E3 ligase 1) containing the C3HC4-type RING domain. CaAIRE1 was induced by ABA and drought, and CaAIRE1 had E3 ligase activity. CaAIRE1-silenced pepper and CaAIRE1-overexpressing Arabidopsis presented drought-sensitive and drought-tolerant phenotypes, respectively, which were accompanied by altered transpiration water loss and ABA sensitivity. Moreover, we found that CaAIRE1 interacts with and ubiquitinates the pepper type 2C protein phosphatase, CaAITP1 (Capsicum annuum CaAIRE1 Interacting Target Phosphatase 1). A cell-free degradation assay with CaAIRE1-silenced peppers and CaAIRE1-overexpressing Arabidopsis plants revealed that the CaAITP1 protein level was negatively modulated by the expression level of CaAIRE1. In contrast to CaAIRE1, CaAITP1-silenced pepper showed ABA-sensitivity phenotypes. CaAITP1-overexpressing Arabidopsis plants were the most insensitive phenotypes to ABA compared with the wild type and other pepper PP2C-overexpressing plants. Taken together, our data indicate that CaAITP1 plays a major role as a negative modulator in ABA signaling, and CaAIRE1 regulates the ABA signaling and drought response through modulation of CaAITP1 stability.