Zhong Xue-Ni, Peng Jun-Jie, Wang Meng-Yao, Yang Xiu-Li, Sun Li
College of Life Science, Shihezi University, Shihezi, Xinjiang, China.
Transgenic Res. 2024 Dec 30;34(1):3. doi: 10.1007/s11248-024-00428-3.
Eremopyrum triticeum is a typical spring ephemeral species, which in China mainly distributed in the desert regions of northern Xinjiang, and play an important role in the desert ecosystems. E. triticeum has several adaptive characteristics such as short growth rhythms, high photosynthetic efficiency, high seed production, drought and salt resistance. However, the molecular regulatory mechanism of E. triticeum in responses to abiotic stress resistance is still unknown. In this study, two NAC-like transcription factor-encoding genes, EtNAC1 and EtNAC2, were isolated from E. triticeum. The predicted EtNAC1 and EtNAC2 proteins possess a typical NAC DNA-binding domain at the N-terminal region. The qRT-PCR analysis showed that EtNAC1 and EtNAC2 were highly expressed in mature roots of E. triticeum, and were significantly up-regulated under drought, high salt and abscisic acid (ABA) stresses. Subcellular localization analysis in onion epidermal cells revealed that EtNAC1 and EtNAC2 were located in the nucleus. Expression of EtNAC1 and EtNAC2 in yeast cells improved the survival rate of yeast under low temperature, HO, high drought and salt stresses. Overexpression of EtNAC1 and EtNAC2 in Arabidopsis thaliana conferred enhanced tolerance to drought and salt stresses, increased ABA sensitivity, and transgenic plants showed higher proline (Pro) content, but lower malondialdehyde content, lower chlorophyll leaching, lower water loss rate and stomatal aperture (width/length) than WT plants. In conclusion, EtNAC1 and EtNAC2 play important roles in abiotic stress responses of E. triticeum, which might have significant potential in crop molecular breeding for abiotic stress tolerance.
东方旱麦草是一种典型的春季短命植物，在中国主要分布于新疆北部的沙漠地区，在沙漠生态系统中发挥着重要作用。东方旱麦草具有生长周期短、光合效率高、种子产量高、耐旱和耐盐等多种适应特性。然而，东方旱麦草响应非生物胁迫抗性的分子调控机制仍不清楚。在本研究中，从东方旱麦草中分离出两个编码NAC类转录因子的基因，即EtNAC1和EtNAC2。预测的EtNAC1和EtNAC2蛋白在N端区域具有典型的NAC DNA结合结构域。qRT-PCR分析表明，EtNAC1和EtNAC2在东方旱麦草的成熟根中高表达，在干旱、高盐和脱落酸（ABA）胁迫下显著上调。洋葱表皮细胞的亚细胞定位分析表明，EtNAC1和EtNAC2位于细胞核中。EtNAC1和EtNAC2在酵母细胞中的表达提高了酵母在低温、H₂O₂、高干旱和盐胁迫下的存活率。在拟南芥中过表达EtNAC1和EtNAC2可增强对干旱和盐胁迫的耐受性，提高ABA敏感性，转基因植株的脯氨酸（Pro）含量较高，但丙二醛含量较低，叶绿素渗漏较少，失水率和气孔孔径（宽度/长度）均低于野生型植株。总之，EtNAC1和EtNAC2在东方旱麦草的非生物胁迫响应中发挥着重要作用，在作物非生物胁迫耐受性分子育种中可能具有巨大潜力。
