Protein degradation by the ubiquitin/26S proteasome system is a critical process that modulates many eukaryotic cellular processes. E3 ligase usually modulates stress response by adjusting the stability of transcription factors. Previous studies have shown that a RING‐type E3 ligase, CaASRF1, positively modulates abscisic acid (ABA) signalling and ABA‐mediated drought response by modulating the stability of CaAIBZ1 and CaATBZ1. In this study, we conducted yeast two‐hybrid (Y2H) screening with CaATBZ1 to isolate an additional modulator, identified as CaATIR1 (Capsicum annuum ATBZ1 Interacting RING finger protein 1). CaATIR1 has E3 ligase activity and promoted CaATBZ1 degradation using the 26S proteasome system. We investigated the loss‐of and gain‐of functions of this E3 ligase by using silencing pepper and overexpressing (OX) Arabidopsis plants, respectively. In response to ABA and drought treatments, CaATIR1 ‐silenced pepper plants showed ABA insensitive and drought‐sensitive phenotypes, while CaATIR1 ‐OX plants showed the opposite phenotypes. Additionally, CaATBZ1 ‐silencing rescued the ABA insensitive and drought‐sensitive phenotypes of CaATIR1 ‐silencing pepper plants. Taken together, these data demonstrate that the stability of CaATBZ1 mediated by CaATIR1 has a crucial role in drought stress signalling in pepper plants.

中文翻译：

---

辣椒RING型E3连接酶CaATIR1通过调节CaATBZ1的稳定性来积极调节脱落酸信号传导和干旱响应。

泛素/ 26S蛋白酶体系统对蛋白质的降解是调节许多真核细胞过程的关键过程。E3连接酶通常通过调节转录因子的稳定性来调节应激反应。先前的研究表明，RING型E3连接酶CaASRF1通过调节CaAIBZ1和CaATBZ1的稳定性来正调节脱落酸（ABA）信号和ABA介导的干旱反应。在这项研究中，我们进行了酵母双杂交（Y2H）与CaATBZ1筛选以分离的附加调制器，鉴定为CaATIR1（ç apsicum一个nnuum AT BZ1我nteracting ř ING指蛋白1）。CaATIR1具有E3连接酶活性，并使用26S蛋白酶体系统促进了CaATBZ1降解。我们分别使用沉默的胡椒和过表达（OX）的拟南芥植物研究了这种E3连接酶的丧失和获得功能。响应ABA和干旱处理，沉默了CaATIR1的辣椒植物表现出ABA不敏感和干旱敏感的表型，而出现了CaATIR1 － OX植物表现出相反的表型。此外，CaATBZ1沉默拯救了CaATIR1沉默辣椒植物的ABA不敏感和干旱敏感表型。综上所述，这些数据表明，由CaATIR1介导的CaATBZ1的稳定性在辣椒植物的干旱胁迫信号传导中具有至关重要的作用。