Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Yangling 712100, Shaanxi, China; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040 Harbin, China.
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040 Harbin, China.
Plant Physiol Biochem. 2017 Apr;113:187-197. doi: 10.1016/j.plaphy.2017.02.007. Epub 2017 Feb 10.
Dehydration-responsive element-binding (DREB) transcription factors are important abiotic stress tolerance related genes, and some reports on the roles of DREB have primarily addressed herbal plants. To explore the abiotic stress tolerance role of DREB (ThDREB) from Tamarix hispida, a ThDREB gene with a complete ORF of 783 bp that encodes a 28.74 kDa protein with 260 amino acids, was isolated and functionally annotated. ThDREB expression was highly induced by NaCl, PEG, NaHCO and CdCl treatments, and the highest expression level (369.2-fold of control) was found for the roots that were under NaCl stress for 6 h. The tobacco plants that were transformed by ThDREB were conferred with higher germination rates, fresh weights and root lengths than the wild type (WT) tobacco plants under NaCl and mannitol treatments. The total chlorophyll content (tcc), superoxide dismutase (SOD) and peroxidase (POD) activities were also higher in the transgenic lines in comparison with the WT, and the malondialdehyde (MDA) and HO content, electrolyte leakage (EL) rate and ROS as tracked by staining were generated to a lesser degree in ThDREB transgenic plants than in the WT under NaCl and mannitol stress. Furthermore, the transient overexpression analysis of ThDREB in T. hispida also improved plant salt and drought tolerance in comparison with the empty vector-transformed lines. Our results indicated that ThDREB expression could effectively improve tolerance to salt and drought stress by enhancing the antioxidase activity that keeps the ROS at a low accumulation level and makes them easy to scavenge.
脱水应答元件结合（DREB）转录因子是重要的非生物胁迫耐受相关基因，一些关于 DREB 作用的报道主要集中在草本植物上。为了探索柽柳（Tamarix hispida）DREB（ThDREB）的非生物胁迫耐受作用，分离并功能注释了一个具有完整 ORF 的 ThDREB 基因，其 ORF 为 783bp，编码一个 28.74kDa 的蛋白质，含有 260 个氨基酸。ThDREB 的表达受 NaCl、PEG、NaHCO 和 CdCl 处理的强烈诱导，在 NaCl 胁迫 6 小时的根中表达水平最高（对照的 369.2 倍）。与野生型（WT）烟草相比，转化了 ThDREB 的烟草在 NaCl 和甘露醇处理下具有更高的发芽率、鲜重和根长。与 WT 相比，转基因系的总叶绿素含量（tcc）、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性也更高，而 MDA 和 HO 含量、电解质渗漏（EL）率和 ROS 染色跟踪的 ROS 生成程度在 NaCl 和甘露醇胁迫下的 ThDREB 转基因植物中要低。此外，ThDREB 在柽柳中的瞬时过表达分析也与空载体转化系相比提高了植物的耐盐和耐旱性。我们的结果表明，ThDREB 的表达可以通过增强抗氧化酶活性来有效提高对盐和干旱胁迫的耐受性，从而保持 ROS 低积累水平并使其易于清除。
