Department of Life Science (BK21 Program), Chung-Ang University, Seoul, 06974, Korea.
Plant Cell Environ. 2017 Oct;40(10):2359-2368. doi: 10.1111/pce.13039. Epub 2017 Aug 24.
Plant adaptive responses to abiotic stress are coordinated by restriction of plant growth and development. The plant hormone abscisic acid (ABA) is the key regulator of the response to abiotic stress, and its sensitivity determines abiotic stress tolerance levels. We previously showed that the E3 ubiquitin ligase CaAIRF1 functions as a positive regulator of ABA and drought stress via modulation of transcription and stability of the type 2C protein phosphatase CaADIP1. Here, we report the identification and functional analysis of a novel-type 2C phosphatase, CaAIPP1 (Capsicum annuum CaAIRF1 Interacting Protein Phosphatase 1). CaAIPP1 interacted with and was ubiquitinated by CaAIRF1. CaAIPP1 gene expression in pepper leaves was induced by ABA and drought. CaAIPP1 degradation was faster in crude protein extracts from ABA-treated pepper plants than in those from control plants. CaAIPP1-overexpressing plants displayed an ABA-hyposensitive phenotype during seed germination and seedling growth. Moreover, these plants exhibited a drought-sensitive phenotype characterized by high levels of transpirational water loss via decreased stomatal closure and reduced leaf temperatures. Our data indicate that CaAIPP1 is a negative regulator of the drought stress response via ABA-mediated signalling. Our findings provide a valuable insight into the plant defence mechanism that operates during drought stress.
植物对非生物胁迫的适应反应是通过限制植物生长和发育来协调的。植物激素脱落酸(ABA)是对非生物胁迫反应的关键调节因子,其敏感性决定了非生物胁迫耐受性水平。我们之前表明,E3 泛素连接酶 CaAIRF1 通过调节转录和 CaADIP1 型 2C 蛋白磷酸酶的稳定性,作为 ABA 和干旱胁迫的正调节剂发挥作用。在这里,我们报道了一种新型 2C 磷酸酶 CaAIPP1(辣椒 CaAIRF1 相互作用蛋白磷酸酶 1)的鉴定和功能分析。CaAIPP1 与 CaAIRF1 相互作用并被其泛素化。ABA 和干旱处理后,辣椒叶片中的 CaAIPP1 基因表达被诱导。与对照植物相比,ABA 处理的辣椒植物粗蛋白提取物中 CaAIPP1 的降解速度更快。CaAIPP1 过表达植物在种子萌发和幼苗生长期间表现出 ABA 低敏感表型。此外,这些植物表现出干旱敏感表型,其特征是通过减少气孔关闭和降低叶片温度导致蒸腾性失水增加。我们的数据表明,CaAIPP1 通过 ABA 介导的信号通路是干旱胁迫反应的负调节剂。我们的研究结果为植物在干旱胁迫期间的防御机制提供了有价值的见解。