The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, Chinese National Center of Plant Gene Research (Wuhan) HUST Part, Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science & Technology (HUST), Wuhan, 430074, China.
Plant Cell Environ. 2013 Aug;36(8):1449-64. doi: 10.1111/pce.12074. Epub 2013 Feb 28.
Abscisic acid (ABA)-, stress-, and ripening-induced (ASR) proteins are reported to be involved in abiotic stresses. However, it is not known whether ASR genes confer drought stress tolerance by utilizing the antioxidant system. In this study, a wheat ASR gene, TaASR1, was cloned and characterized. TaASR1 transcripts increased after treatments with PEG6000, ABA and H(2)O(2). Overexpression of TaASR1 in tobacco resulted in increased drought/osmotic tolerance, which was demonstrated that transgenic lines had lesser malondialdehyde (MDA), ion leakage (IL) and reactive oxygen species (ROS), but higher relative water content (RWC) and superoxide dismutase (SOD) and catalase (CAT) activities than wild type (WT) under drought stress. Overexpression of TaASR1 in tobacco also enhanced the expression of ROS-related and stress-responsive genes under osmotic stress. In addition, transgenic lines exhibited improved tolerance to oxidative stress by retaining more effective antioxidant system. Finally, TaASR1 was localized in the cell nucleus and functioned as a transcriptional activator. Taken together, our results showed that TaASR1 functions as a positive factor under drought/osmotic stress, involved in the regulation of ROS homeostasis by activating antioxidant system and transcription of stress-associated genes.
脱落酸（ABA）、胁迫和成熟诱导（ASR）蛋白被报道参与非生物胁迫。然而，目前尚不清楚 ASR 基因是否通过利用抗氧化系统赋予耐旱性。在这项研究中，克隆并鉴定了一个小麦 ASR 基因 TaASR1。PEG6000、ABA 和 H2O2 处理后 TaASR1 转录本增加。在烟草中超表达 TaASR1 导致耐旱/耐渗胁迫能力增强，表明转基因株系在干旱胁迫下丙二醛（MDA）、离子渗漏（IL）和活性氧（ROS）含量较低，相对水含量（RWC）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性较高，而野生型（WT）则较低。在渗透胁迫下，超表达 TaASR1 也增强了与 ROS 相关和应激反应基因的表达。此外，通过保留更有效的抗氧化系统，转基因株系表现出对氧化胁迫的耐受性提高。最后，TaASR1 定位于细胞核内，作为转录激活因子发挥作用。总之，我们的研究结果表明，TaASR1 在干旱/渗透胁迫下作为一个正调控因子发挥作用，通过激活抗氧化系统和应激相关基因的转录来调节 ROS 平衡。
