An extreme temperature regime beyond desired level imposes significant stress in crop plants. The low and high temperature stresses are one of the primary constraints for plant development and yield. Finger millet, being a climate resilient crop, is a potential source of novel stress tolerant genes. In this study, functional characterization of finger millet DREB2A gene in different abiotic stress conditions was done. This novel EcDREB2A transcription factor isolated from finger millet is a truncated version of DREB2A gene compared to previously reported DREB genes from other plant species. The overexpression of EcDREB2A in transgenic tobacco exhibits improved tolerance against heat stress 42 °C for up to 7 days, by altering physiology and biochemical means. However, same transgenic lines were unable to provide tolerance to 200 mM NaCl and 200 mM Mannitol stress. Under heat stress conditions, increased seed germination with improved lateral roots, fresh and dry weight relative to wild type (WT) was observed. The EcDREB2A transgenics exposed to heat stress showed improved rate of stomatal conductance, chlorophyll and carotenoids contents, and other photosynthesis parameters compared to WT plants. EcDREB2A overexpression also resulted in increased antioxidant enzyme activity (SOD, CAT, GR, POD and, APX) with decreased electrolyte leakage (EL), H₂O_2, and malondialdehyde (MDA) content than WT plants under heat stress. Quantitative real time expression analysis demonstrated that all eight downstream genes were significantly upregulated in transgenic plants only after heat stress. Our data provide a clear demonstration of the positive impact of overexpression of EcDREB2A providing heat stress tolerance to plants.

超出预期水平的极端温度制度对作物植物施加了显着的压力。低温和高温胁迫是植物发育和产量的主要制约因素之一。手指小米是一种气候适应性强的作物，是新型抗逆基因的潜在来源。本研究对指黍DREB2A基因在不同非生物胁迫条件下的功能进行了表征。这种从手指小米中分离出的新型 EcDREB2A 转录因子是DREB2A的截短版本基因与先前报道的来自其他植物物种的 DREB 基因相比。通过改变生理学和生化手段，EcDREB2A 在转基因烟草中的过表达对 42°C 热应激的耐受性提高了长达 7 天。然而，相同的转基因品系不能提供对 200 mM NaCl 和 200 mM 甘露醇胁迫的耐受性。在热应激条件下，观察到种子发芽增加，侧根、鲜重和干重相对于野生型 (WT) 有所改善。与 WT 植物相比，暴露于热应激的 EcDREB2A 转基因植物的气孔导度、叶绿素和类胡萝卜素含量以及其他光合作用参数均有所提高。EcDREB2A 过表达还导致抗氧化酶活性（SOD、CAT、GR、POD 和 APX）增加，电解质泄漏 (EL)、H₂ O ₂和丙二醛（MDA）含量高于热胁迫下的WT植物。定量实时表达分析表明，所有八个下游基因仅在热应激后在转基因植物中显着上调。我们的数据清楚地证明了 EcDREB2A 过表达对植物提供热胁迫耐受性的积极影响。