Basic Leucine Zipper (bZIP) transcription factors (TFs) play important roles in many processes, especially in abiotic stress response in plants. In this study, we characterized a new gene EHANCED DROUGHT TOLERANCE 1 (EDT1), member of group E of bZIP transcription factor family in rice. The EDT1 protein contains one bZIP domain, one putative nuclear localization signal (NLS) and six conserved phosphorylation sites. The expression of EDT1 is suppressed by several abiotic stresses, such as cold, droutht, and salt. Corresponding with expression patterns, several stress-associated cis-acting elements were found in the EDT1 promoter. The results of subcellular localization and transactivation ability analyses indicated that EDT1 was localized in the nucleus and functioned as a nuclear protein, with its transactivation activity primarily located in N-terminal. Transgenic rice overexpressing EDT1 showed drought tolerance that has been significantly improved. Real-time PCR analysis revealed that some stress-related genes, such as OsbZIP12, SNAC1, OsLEA3, OsbZIP16, OsbZIP10 and OsABI2 were up-regulated in EDT1 overexpression lines. These results indicate that EDT1 plays a positive role in drought tolerance and provides valuable targets for breeding drought-tolerant rice cultivars.
堿性亮氨酸拉鏈bZIP轉(zhuǎn)錄因子在許多過程中發(fā)揮重要作用，特別是在植物的非生物脅迫應答中。本研究中，我們鑒定了一個新的基因，即水稻bZIP轉(zhuǎn)錄因子家族E族的成員，干旱性增強基因EDT1。EDT1蛋白包含一個bZIP結構域、一個預測的核定位信號（NLS）和六個保守的磷酸化位點。EDT1的表達受到冷、旱、鹽等非生物脅迫的抑制。對應于表達模式，在EDT1啟動子中發(fā)現(xiàn)了一些與應激相關的順式作用元件。亞細胞定位和反式激活能力分析結果表明，EDT1定位于細胞核，具有核蛋白功能，其反式激活活性主要位于N-末端。過表達EDT1的轉(zhuǎn)基因水稻表現(xiàn)出明顯的抗旱性。實時PCR分析表明，EDT1高表達系中OsbZIP12, SNAC1, OsLEA3, OsbZIP16, OsbZIP10和OsABI2等逆境相關基因表達上調(diào)。這些結果表明，EDT1在水稻抗旱性中起著積極的作用，為水稻抗旱品種的選育提供了有價值的指標。