Yao Yuan, He Run Jun, Xie Qiao Li, Zhao Xian Hai, Deng Xiao Mei, He Jun Bo, Song Lili, He Jun, Marchant Alan, Chen Xiao-Yang, Wu Ai-Min
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
New Phytol. 2017 Mar;213(4):1667-1681. doi: 10.1111/nph.14278. Epub 2016 Nov 7.
Recent studies indicate that the ETHYLENE RESPONSE FACTOR VII (ERF-VII) transcription factor is an important regulator of osmotic and hypoxic stress responses in plants. However, the molecular mechanism of ERF-VII-mediated transcriptional regulation remains unclear. Here, we investigated the role of ERF74 (a member of the ERF-VII protein family) by examining the abiotic stress tolerance of an ERF74 overexpression line and a T-DNA insertion mutant using flow cytometry, transactivation and electrophoretic mobility shift assays. 35S::ERF74 showed enhanced tolerance to drought, high light, heat and aluminum stresses, whereas the T-DNA insertion mutant erf74 and the erf74;erf75 double mutant displayed higher sensitivity. Using flow cytometry analysis, we found that erf74 and erf74;erf75 lines lack the reactive oxygen species (ROS) burst in the early stages of various stresses, as a result of the lower expression level of RESPIRATORY BURST OXIDASE HOMOLOG D (RbohD). Furthermore, ERF74 directly binds to the promoter of RbohD and activates its expression under different abiotic stresses. Moreover, induction of stress marker genes and ROS-scavenging enzyme genes under various stress conditions is dependent on the ERF74-RbohD-ROS signal pathway. We propose a pathway that involves ERF74 acting as an on-off switch controlling an RbohD-dependent mechanism in response to different stresses, subsequently maintaining hydrogen peroxide (H O ) homeostasis in Arabidopsis.
近期研究表明，乙烯反应因子VII（ERF-VII）转录因子是植物渗透胁迫和低氧胁迫反应的重要调节因子。然而，ERF-VII介导的转录调控分子机制仍不清楚。在此，我们通过使用流式细胞术、反式激活和电泳迁移率变动分析，检测ERF74过表达株系和T-DNA插入突变体的非生物胁迫耐受性，研究了ERF74（ERF-VII蛋白家族成员之一）的作用。35S::ERF74对干旱、高光、高温和铝胁迫的耐受性增强，而T-DNA插入突变体erf74和erf74;erf75双突变体表现出更高的敏感性。通过流式细胞术分析，我们发现erf74和erf74;erf75株系在各种胁迫早期缺乏活性氧（ROS）爆发，这是由于呼吸爆发氧化酶同源物D（RbohD）表达水平较低所致。此外，ERF74直接结合RbohD的启动子，并在不同非生物胁迫下激活其表达。而且，各种胁迫条件下胁迫标记基因和ROS清除酶基因的诱导依赖于ERF74-RbohD-ROS信号通路。我们提出了一条途径，其中ERF74作为一个开关，控制RbohD依赖的机制以响应不同胁迫，随后在拟南芥中维持过氧化氢（H₂O₂）稳态。
