Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, College of Forestry, Hainan University, Haikou, Hainan province, 570228, China.
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, College of Forestry, Hainan University, Haikou, Hainan province, 570228, China.
Plant Physiol Biochem. 2020 Nov;156:155-166. doi: 10.1016/j.plaphy.2020.09.015. Epub 2020 Sep 14.
WRKY transcription factors play key roles in plant biotic and abiotic stress responses, but the function of some MaWRKYs remains elusive. Here, we characterized the positive role of MaWRKY80 in drought stress resistance and the underlying mechanism. MaWRKY80 was significantly upregulated under drought stress and confirmed as a transcription factor that could bind to the W-box. Overexpression of MaWRKY80 in Arabidopsis showed better phenotypic morphology, higher survival rate, less water loss rate, and lower malondialdehyde level than wild type (WT) under drought stress. Consistently, MaWRKY80 transgenic Arabidopsis leaves displayed significantly lower reactive oxygen species (ROS) than WT under drought stress. Moreover, MaWRKY80 mediated the stomata movement and leaf water retention capacity through modulation of the transcript of 9-cis-epoxycarotenoid dioxygenases (NCEDs) and abscisic acid (ABA) biosynthesis in Arabidopsis. Notably, chromatin immunoprecipitation quantitative real-time PCR (ChIP-PCR) and electrophoretic mobility shift assay (EMSA) provided evidences supporting the direct and specific interaction between MaWRKY80 and both the W-box in AtNCEDs promoter in Arabidopsis and the W-box in MaNCEDs promoter in banana. Taken together, MaWRKY80 serves as a positive regulator of drought stress resistance through modulating ABA level by regulating NCEDs expression and ROS accumulation by regulating antioxidant system. This study provides a novel insight into MaWRKY80 in coordinating ABA synthesis and ROS elimination in response to drought stress.
WRKY 转录因子在植物生物和非生物胁迫反应中发挥关键作用，但某些 MaWRKY 的功能仍然难以捉摸。在这里，我们描述了 MaWRKY80 在抗旱性中的积极作用及其潜在机制。在干旱胁迫下，MaWRKY80 显著上调，并被确认为能够与 W-box 结合的转录因子。在拟南芥中过表达 MaWRKY80 ，与野生型（WT）相比，在干旱胁迫下表现出更好的表型形态、更高的存活率、更低的失水率和更低的丙二醛水平。一致地，在干旱胁迫下，MaWRKY80 转基因拟南芥叶片中的活性氧（ROS）水平明显低于 WT。此外，MaWRKY80 通过调节拟南芥中 9-顺式-环氧类胡萝卜素双加氧酶（NCEDs）和脱落酸（ABA）生物合成的转录本，介导气孔运动和叶片保水能力。值得注意的是，染色质免疫沉淀定量实时 PCR（ChIP-PCR）和电泳迁移率变动分析（EMSA）提供了证据支持 MaWRKY80 与拟南芥 AtNCEDs 启动子中的 W-box 以及香蕉 MaNCEDs 启动子中的 W-box 之间的直接和特异性相互作用。综上所述，MaWRKY80 通过调节 NCEDs 的表达来调节 ABA 水平，通过调节抗氧化系统来调节 ROS 积累，从而作为抗旱性的正调控因子发挥作用。本研究为 MaWRKY80 在协调 ABA 合成和 ROS 消除以响应干旱胁迫提供了新的见解。
