State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, People's Republic of China.
College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, People's Republic of China.
Plant Physiol Biochem. 2016 Aug;105:55-66. doi: 10.1016/j.plaphy.2016.04.018. Epub 2016 Apr 11.
Abiotic stress has been shown to significantly limit the growth and productivity of crops. NAC transcription factors play essential roles in response to various abiotic stresses. However, only little information regarding stress-related NAC genes is available in maize. Here, we cloned a maize NAC transcription factor ZmNAC55 and identified its function in drought stress. Transient expression and transactivation assay demonstrated that ZmNAC55 was localized in the nucleus and had transactivation activity. Expression analysis of ZmNAC55 in maize showed that this gene was induced by drought, high salinity and cold stresses and by abscisic acid (ABA). Promoter analysis demonstrated that multiple stress-related cis-acting elements exist in promoter region of ZmNAC55. Overexpression of ZmNAC55 in Arabidopsis led to hypersensitivity to ABA at the germination stage, but enhanced drought resistence compared to wild-type seedlings. Transcriptome analysis identified a number of differentially expressed genes between 35S::ZmNAC55 transgenic and wild-type plants, and many of which are involved in stress response, including twelve qRT-PCR confirmed well-known drought-responsive genes. These results highlight the important role of ZmNAC55 in positive regulates of drought resistence, and may have potential applications in transgenic breeding of drought-tolerant crops.
非生物胁迫显著限制了作物的生长和生产力。NAC 转录因子在应对各种非生物胁迫方面发挥着重要作用。然而，玉米中与胁迫相关的 NAC 基因的信息却很少。在这里，我们克隆了一个玉米 NAC 转录因子 ZmNAC55，并鉴定了它在干旱胁迫中的功能。瞬时表达和转录激活分析表明，ZmNAC55 定位于细胞核内，具有转录激活活性。玉米中 ZmNAC55 的表达分析表明，该基因受到干旱、高盐和低温胁迫以及脱落酸（ABA）的诱导。启动子分析表明，ZmNAC55 启动子区存在多个与胁迫相关的顺式作用元件。在拟南芥中过表达 ZmNAC55 导致其在萌发阶段对 ABA 敏感，但与野生型幼苗相比，抗旱性增强。转录组分析鉴定了 35S::ZmNAC55 转基因和野生型植物之间的许多差异表达基因，其中许多基因参与胁迫反应，包括 12 个 qRT-PCR 验证的已知抗旱响应基因。这些结果突出了 ZmNAC55 在正向调控抗旱性方面的重要作用，并且在抗旱作物的转基因育种中可能具有潜在的应用价值。
