Wang Bingxin, Li Liqun, Peng De, Liu Mingliu, Wei Aosong, Li Xuejun
State Key Laboratory of Crop Stress Biology in Arid Areas and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Plant Sci. 2021 Oct;311:111022. doi: 10.1016/j.plantsci.2021.111022. Epub 2021 Aug 14.
Drought has negative effects on cereal production. Studies have shown that many basic leucine zipper transcription factors (bZIP TFs) help to cope with drought stress. In this study, bZIP TF wheat (Triticum aestivum L.) FD-Like2 (TaFDL2) was isolated and functionally analyzed. Three homologs of TaFDL2 were identified and their expression was induced by drought and abscisic acid (ABA) treatment. TaFDL2-1A has transactivation activity and two activation domains, and the domain D region has different effects on the transcriptional activity of the two domains. Analysis of TaFDL2-1A overexpression plants indicated their enhanced drought tolerance and greater sensitivity to ABA. TabZIP8-7A was identified as a protein that interacts with TaFDL2-1A in the nucleus, and the overexpression of TabZIP8-7A conferred greater drought resistance and ABA sensitivity in Arabidopsis. Surprisingly, TaFDL2-1A × TabZIP8-7A double overexpression lines exhibited the highest drought resistance. Genetic and transcriptional regulation analyses demonstrated that stress-response gene transcription was initiated by TaFDL2-1A or TabZIP8-7A via the ABA signaling pathway. Importantly, TaFDL2-1A and TabZIP8-7A synergistically promoted ABA-inducible gene expression in a more efficient manner to form the transcriptional activation complex. Our findings provide new insights into the molecular mechanisms that allow bZIP TFs to regulate ABA signaling in response to drought stress.
干旱对谷物生产有负面影响。研究表明，许多碱性亮氨酸拉链转录因子（bZIP TFs）有助于应对干旱胁迫。在本研究中，对bZIP TF小麦（Triticum aestivum L.）FD-Like2（TaFDL2）进行了分离和功能分析。鉴定出TaFDL2的三个同源物，其表达受干旱和脱落酸（ABA）处理诱导。TaFDL2-1A具有反式激活活性和两个激活域，结构域D区域对这两个域的转录活性有不同影响。对TaFDL2-1A过表达植株的分析表明其耐旱性增强且对ABA更敏感。TabZIP8-7A被鉴定为一种在细胞核中与TaFDL2-1A相互作用的蛋白质，TabZIP8-7A的过表达使拟南芥具有更强的抗旱性和ABA敏感性。令人惊讶的是，TaFDL2-1A×TabZIP8-7A双过表达株系表现出最高的抗旱性。遗传和转录调控分析表明，应激反应基因转录由TaFDL2-1A或TabZIP8-7A通过ABA信号通路启动。重要的是，TaFDL2-1A和TabZIP8-7A以更有效的方式协同促进ABA诱导基因的表达，形成转录激活复合体。我们的研究结果为bZIP TFs响应干旱胁迫调节ABA信号的分子机制提供了新见解。
