Homeodomain-leucine zipper (HD-Zip) IV transcription factors are integral in the plant response to abiotic stressors. In maize, few HD-Zip IV proteins have yet been reported, and the functions are not well understood. In the current study, we isolated ZmHDZIV14 from the HD-Zip IV transcription factor family from maize and characterized its role in the stress response. We conducted a phylogenetic analysis showing that there was high homology and thus likely similar functions between ZmHDZIV14 and AtHDG11. Heterologous overexpression of ZmHDZIV14 in Arabidopsis caused increased sensitivity to abscisic acid (ABA), tolerance of salt and mannitol at germination stage, and drought tolerance of seedlings. ZmHDZIV14 transgenic Arabidopsis lines placed under drought stress additionally displayed lower levels of malondialdehyde, higher proline, and relative water content, compared to the wild-type. Further, modified tobacco plants (35S::ZmHDZIV14) responded to drought conditions with appropriate stomatal changes. After drought was relieved, expression of P5CS1, RD22, RD29B, RAB18, NCED3, and ERD1 were upregulated in transgenic Arabidopsis. It can be seen ZmHDZIV14 expression resulted in physiological and molecular changes in the transgenic lines, which improved overall drought tolerance. In summary, our results indicate that ZmHDZIV14 is a transcriptional regulator that modifies an ABA-dependent signaling pathway to regulate the drought response in plants.

中文翻译：

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玉米 ZmHDZIV14 的过表达增加了拟南芥和烟草的脱落酸敏感性并介导了干旱和盐胁迫

同源域-亮氨酸拉链 (HD-Zip) IV 转录因子是植物对非生物胁迫的反应中不可或缺的一部分。在玉米中，很少有 HD-Zip IV 蛋白的报道，其功能还不是很清楚。在目前的研究中，我们从玉米的 HD-Zip IV 转录因子家族中分离出 ZmHDZIV14，并表征了其在应激反应中的作用。我们进行了系统发育分析，表明 ZmHDZIV14 和 AtHDG11 之间存在高度同源性，因此可能具有相似的功能。ZmHDZIV14 在拟南芥中的异源过表达导致对脱落酸 (ABA) 的敏感性增加，萌发阶段对盐和甘露醇的耐受性以及幼苗的耐旱性增加。置于干旱胁迫下的 ZmHDZIV14 转基因拟南芥品系还显示出较低水平的丙二醛、较高的脯氨酸、和相对含水量，与野生型相比。此外，改良的烟草植物 (35S::ZmHDZIV14) 以适当的气孔变化应对干旱条件。干旱缓解后，转基因拟南芥中P5CS1、RD22、RD29B、RAB18、NCED3和ERD1的表达上调。可以看出，ZmHDZIV14 的表达导致转基因株系的生理和分子变化，从而提高了整体抗旱性。总之，我们的结果表明，ZmHDZIV14 是一种转录调节因子，可修饰 ABA 依赖性信号通路以调节植物的干旱反应。和 ERD1 在转基因拟南芥中上调。可以看出，ZmHDZIV14 的表达导致转基因株系的生理和分子变化，从而提高了整体抗旱性。总之，我们的结果表明，ZmHDZIV14 是一种转录调节因子，可修饰 ABA 依赖性信号通路以调节植物的干旱反应。和 ERD1 在转基因拟南芥中上调。可以看出，ZmHDZIV14 的表达导致转基因株系的生理和分子变化，从而提高了整体抗旱性。总之，我们的结果表明，ZmHDZIV14 是一种转录调节因子，可修饰 ABA 依赖性信号通路以调节植物的干旱反应。