Joo Hyunhee, Lim Chae Woo, Han Sang-Wook, Lee Sung Chul
Department of Life Science (BK21 Program), Chung-Ang UniversitySeoul, South Korea.
Department of Integrative Plant Science, Chung-Ang UniversityAnseong, South Korea.
Front Plant Sci. 2017 Apr 28;8:690. doi: 10.3389/fpls.2017.00690. eCollection 2017.
Drought stress from soil or air limits plant growth and development, leading to a reduction in crop productivity. Several E3 ligases positively or negatively regulate the drought stress response. In the present study, we show that the pepper () Drought Induced RING type E3 ligase 1, CaDIR1, regulates the drought stress response via abscisic acid (ABA)-mediated signaling. CaDIR1 contains a C3HC4-type RING finger domain in the N-terminal region; this domain functions during protein degradation via attachment of ubiquitins to the substrate target proteins. The expression levels of the gene were suppressed and induced by ABA and drought treatments, respectively. We conducted loss-of-function and gain-of function genetic studies to examine the function of in response to ABA and drought stress. -silenced pepper plants displayed a drought-tolerant phenotype characterized by a low level of transpirational water loss via increased stomatal closure and elevated leaf temperatures. overexpressing (OX) Arabidopsis plants exhibited an ABA-hypersensitive phenotype during the germination stage, but an ABA-hyposensitive phenotype-characterized by decreased stomatal closure and reduced leaf temperatures-at the adult stage. Moreover, adult OX plants exhibited a drought-sensitive phenotype characterized by high levels of transpirational water loss. Our results indicate that CaDIR1 functions as a negative regulator of the drought stress response via ABA-mediated signaling. Our findings provide a valuable insight into the plant defense mechanism that operates during drought stress.
土壤或空气造成的干旱胁迫会限制植物的生长发育，导致作物产量下降。几种E3连接酶对干旱胁迫反应有正向或负向调节作用。在本研究中，我们发现辣椒干旱诱导型RING型E3连接酶1（CaDIR1）通过脱落酸（ABA）介导的信号传导来调节干旱胁迫反应。CaDIR1在N端区域含有一个C3HC4型RING指结构域；该结构域在通过将泛素附着到底物靶蛋白上来进行蛋白质降解的过程中发挥作用。CaDIR1基因的表达水平分别受到ABA和干旱处理的抑制和诱导。我们进行了功能缺失和功能获得的遗传学研究，以检验CaDIR1在响应ABA和干旱胁迫时的功能。CaDIR1沉默的辣椒植株表现出耐旱表型，其特征是通过增加气孔关闭和提高叶片温度来降低蒸腾失水水平。CaDIR1过表达（OX）的拟南芥植株在萌发阶段表现出ABA超敏表型，但在成年阶段表现出ABA低敏表型，其特征是气孔关闭减少和叶片温度降低。此外，成年OX植株表现出以高蒸腾失水水平为特征的干旱敏感表型。我们的结果表明，CaDIR1通过ABA介导的信号传导作为干旱胁迫反应的负调节因子发挥作用。我们的发现为干旱胁迫期间起作用的植物防御机制提供了有价值的见解。
