Department of Life Science (BK21 program), Chung-Ang University, Seoul, 06974, Korea.
Plant J. 2019 Apr;98(1):5-18. doi: 10.1111/tpj.14191. Epub 2019 Jan 30.
Plants have evolved complex defense mechanisms to adapt and survive under adverse growth conditions. Abscisic acid (ABA) is a phytohormone that plays a pivotal role in the stress response, especially regulation of the stomatal aperture in response to drought. Here, we identified the pepper CaASRF1 (Capsicum annuum ABA Sensitive RING Finger E3 ligase 1) gene, which modulates drought stress tolerance via ABA-mediated signaling. CaASRF1 contains a C3H2C3-type RING finger domain, which functions as an E3 ligase by attaching ubiquitins to the target proteins. CaASRF1 expression was enhanced after exposure to ABA, drought and NaCl. Loss-of-function in pepper plants and gain-of-function in Arabidopsis plants revealed that CaASRF1 positively modulates ABA signaling and the drought stress response. Moreover, CaASRF1 interacted with and was associated with degradation of the bZIP transcription factor CaAIBZ1 (Capsicum annuum ASRF1-Interacting bZIP transcription factor 1). Contrary to CaASRF1 phenotypes, CaAIBZ1-silenced pepper and CaAIBZ1-overexpressing Arabidopsis exhibited drought-tolerant and drought-sensitive phenotypes, respectively. Taken together, our data indicate that CaASRF1 positively modulates ABA signaling and the drought stress response via modulation of CaAIBZ1 stability.
植物已经进化出复杂的防御机制，以适应和在不利的生长条件下生存。脱落酸（ABA）是一种植物激素，在应激反应中起着关键作用，特别是调节气孔孔径以响应干旱。在这里，我们鉴定了辣椒 CaASRF1（辣椒 ABA 敏感 RING 指 E3 连接酶 1）基因，该基因通过 ABA 介导的信号转导调节干旱胁迫耐受性。CaASRF1 含有 C3H2C3 型 RING 指结构域，通过将泛素连接到靶蛋白上作为 E3 连接酶发挥作用。CaASRF1 的表达在暴露于 ABA、干旱和 NaCl 后增强。辣椒植物中的功能丧失和拟南芥植物中的功能获得表明，CaASRF1 正向调节 ABA 信号转导和干旱胁迫反应。此外，CaASRF1 与 bZIP 转录因子 CaAIBZ1（辣椒 ASRF1 相互作用 bZIP 转录因子 1）相互作用并与之相关，导致其降解。与 CaASRF1 表型相反，CaAIBZ1 沉默的辣椒和 CaAIBZ1 过表达的拟南芥分别表现出耐旱和耐旱表型。总之，我们的数据表明，CaASRF1 通过调节 CaAIBZ1 的稳定性正向调节 ABA 信号转导和干旱胁迫反应。
