Department of Life Science (BK21 program), Chung-Ang University, Seoul, 06974, Republic of Korea.
Department of Physical Education, Chung-Ang University, Seoul, 06974, Republic of Korea.
Sci Rep. 2017 Mar 28;7(1):477. doi: 10.1038/s41598-017-00490-4.
Drought stress conditions in soil or air hinder plant growth and development. Here, we report that the hot pepper (C apsicum a nnuum) RING type E3 Ligase 1 gene (CaREL1) is essential to the drought stress response. CaREL1 encodes a cytoplasmic- and nuclear-localized protein with E3 ligase activity. CaREL1 expression was induced by abscisic acid (ABA) and drought. CaREL1 contains a C3H2C3-type RING finger motif, which functions in ubiquitination of the target protein. We used CaREL1-silenced pepper plants and CaREL1-overexpressing (OX) transgenic Arabidopsis plants to evaluate the in vivo function of CaREL1 in response to drought stress and ABA treatment. CaREL1-silenced pepper plants displayed a drought-tolerant phenotype characterized by ABA hypersensitivity. In contrast, CaREL1-OX plants exhibited ABA hyposensitivity during the germination, seedling, and adult stages. In addition, plant growth was severely impaired under drought stress conditions, via a high level of transpirational water loss and decreased stomatal closure. Quantitative RT-PCR analyses revealed that ABA-related drought stress responsive genes were more weakly expressed in CaREL1-OX plants than in wild-type plants, indicating that CaREL1 functions in the drought stress response via the ABA-signalling pathway. Taken together, our results indicate that CaREL1 functions as a negative regulator of ABA-mediated drought stress tolerance.
土壤或空气中的干旱胁迫条件会阻碍植物的生长和发育。在这里，我们报告说辣椒（Capsicum annum）的 RING 型 E3 连接酶 1 基因（CaREL1）是对干旱胁迫反应所必需的。CaREL1 编码一种具有 E3 连接酶活性的细胞质和核定位蛋白。CaREL1 的表达受脱落酸（ABA）和干旱诱导。CaREL1 含有 C3H2C3 型 RING 指基序，该基序在靶蛋白的泛素化中起作用。我们使用 CaREL1 沉默的辣椒植物和 CaREL1 过表达（OX）的拟南芥转基因植物来评估 CaREL1 在应对干旱胁迫和 ABA 处理中的体内功能。CaREL1 沉默的辣椒植物表现出耐旱表型，其特征是 ABA 超敏性。相比之下，CaREL1-OX 植物在萌发、幼苗和成年阶段表现出 ABA 低敏性。此外，在干旱胁迫条件下，植物生长受到严重损害，通过高水平的蒸腾失水和减少的气孔关闭。定量 RT-PCR 分析显示，CaREL1-OX 植物中 ABA 相关的干旱胁迫响应基因的表达弱于野生型植物，表明 CaREL1 通过 ABA 信号通路在干旱胁迫反应中发挥作用。总之，我们的结果表明 CaREL1 作为 ABA 介导的耐旱性的负调节剂发挥作用。
