Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Xinjiang Urumqi 830011, China.
BMC Plant Biol. 2014 Feb 10;14:44. doi: 10.1186/1471-2229-14-44.
Dehydration-Responsive Element-Binding Protein2 (DREB2) is a transcriptional factor which regulates the expression of several stress-inducible genes. DREB2-type proteins are particularly important in plant responses to drought, salt and heat. DREB2 genes have been identified and characterized in a variety of plants, and DREB2 genes are promising candidate genes for the improvement of stress tolerance in plants. However, little is known about these genes in plants adapted to water-limiting environments.
In this study, we describe the characterization of EsDREB2B, a novel DREB2B gene identified from the desert plant Eremosparton songoricum. Phylogenetic analysis and motif prediction indicate that EsDREB2B encodes a truncated DREB2 polypeptide that belongs to a legume-specific DREB2 group. In E. songoricum, EsDREB2B transcript accumulation was induced by a variety of abiotic stresses, including drought, salinity, cold, heat, heavy metal, mechanical wounding, oxidative stress and exogenous abscisic acid (ABA) treatment. Consistent with the predicted role as a transcription factor, EsDREB2B was targeted to the nucleus of onion epidermal cells and exhibited transactivation activity of a GAL4-containing reporter gene in yeast. In transgenic yeast, overexpression of EsDREB2B increased tolerance to multiple abiotic stresses. Our findings indicate that EsDREB2B can enhance stress tolerance in other plant species. Heterologous expression of EsDREB2B in tobacco showed improved tolerance to multiple abiotic stresses, and the transgenic plants exhibited no reduction in foliar growth. We observed that EsDREB2B is a functional DREB2-orthologue able to influence the physiological and biochemical response of transgenic tobacco to stress.
Based upon these findings, EsDREB2B encodes an abiotic stress-inducible, transcription factor which confers abiotic stress-tolerance in yeast and transgenic tobacco.
脱水响应元件结合蛋白 2（DREB2）是一种转录因子，可调节几种胁迫诱导基因的表达。DREB2 型蛋白在植物对干旱、盐和热的响应中尤为重要。已经在多种植物中鉴定和描述了 DREB2 基因，并且 DREB2 基因是提高植物胁迫耐受性的有前途的候选基因。然而，对于适应缺水环境的植物中的这些基因知之甚少。
在这项研究中，我们描述了沙漠植物半日花中新鉴定的 DREB2B 基因 EsDREB2B 的特征。系统进化分析和基序预测表明，EsDREB2B 编码一种截断的 DREB2 多肽，属于豆科特异性 DREB2 组。在半日花中，EsDREB2B 转录本的积累受到多种非生物胁迫的诱导，包括干旱、盐度、寒冷、高温、重金属、机械损伤、氧化应激和外源脱落酸（ABA）处理。与作为转录因子的预测作用一致，EsDREB2B 靶向洋葱表皮细胞的核，并在酵母中表现出含有 GAL4 的报告基因的转录激活活性。在转基因酵母中，EsDREB2B 的过表达增加了对多种非生物胁迫的耐受性。我们的研究结果表明，EsDREB2B 可以增强其他植物物种的胁迫耐受性。EsDREB2B 在烟草中的异源表达显示出对多种非生物胁迫的耐受性提高，并且转基因植物的叶片生长没有减少。我们观察到 EsDREB2B 是一种功能齐全的 DREB2 同源物，能够影响转基因烟草对胁迫的生理和生化反应。
基于这些发现，EsDREB2B 编码一种非生物胁迫诱导的转录因子，可在酵母和转基因烟草中赋予非生物胁迫耐受性。
