Abiotic stress, such as drought and flooding, are responsible for considerable losses in grain production worldwide. Soybean, the main cultivated oilseed in the world, is sensitive to both stresses. Plant molecular mechanisms answer via crosstalk of several signaling pathways, in which particular genes can respond to different stresses. Previous studies confirmed that overexpression of transcription factor AtAREB1 confers drought tolerance in soybean. However, plants containing this gene have not yet been tested under flooding. Thus, the objective of this study was to characterize genetically modified (GM) soybean plants overexpressing AtAREB1 under drought and flooding conditions in comparison to its genetic background. Physiological and biochemical measurements were performed. In addition, the expression level of genes commonly activated under both stresses was evaluated. The results supported the role of the AtAREB1 gene in conferring tolerance to water deficit in soybeans. Furthermore, under flooding, the GM line was efficient in maintaining a higher photosynthetic rate, intrinsic efficiency in water use, and instantaneous carboxylation efficiency, resulting in higher grain yield under stress. The GM line also presented higher protein content, lower concentration of hydrogen peroxide, and lower expression levels of genes related to fermentative metabolism and alanine biosynthesis. These results indicate that in addition to drought stress, plants overexpressing AtAREB1 exhibited better performance under flooding when compared to the non-GM line, suggesting a cross-signaling response to both abiotic factors.

中文翻译：

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拟南芥bZIP转录因子AREB1的组成型表达激活大豆在干旱和洪水胁迫下的交叉信号反应


干旱和洪水等非生物胁迫造成了全球粮食生产的巨大损失。大豆是世界上主要的栽培油籽，对这两种胁迫都很敏感。植物分子机制通过几种信号通路的串扰来回答，其中特定的基因可以对不同的胁迫做出反应。先前的研究证实转录因子AtAREB1的过度表达赋予大豆耐旱性。然而，含有该基因的植物尚未在洪水下进行测试。因此，本研究的目的是与其遗传背景相比，表征在干旱和洪水条件下过度表达 AtAREB1 的转基因 (GM) 大豆植物。进行生理和生化测量。此外，还评估了两种胁迫下通常激活的基因的表达水平。结果支持 AtAREB1 基因在赋予大豆耐水亏缺方面的作用。此外，在洪水条件下，转基因品系能够有效维持较高的光合速率、水分利用的内在效率和瞬时羧化效率，从而在胁迫下提高谷物产量。 GM系还表现出较高的蛋白质含量、较低的过氧化氢浓度以及与发酵代谢和丙氨酸生物合成相关的基因的表达水平较低。这些结果表明，除了干旱胁迫之外，与非转基因品系相比，过表达AtAREB1的植物在洪水下表现出更好的性能，这表明对两种非生物因素的交叉信号反应。