NAC transcription factors (TFs) play critical roles in plant abiotic stress responses. However, information on the roles of NAC TFs is limited in wheat (Triticum aestivum L.). In this study, we isolated three wheat TaSNAC4 homeologous genes, TaSNAC4-3A, TaSNAC4-3B, and TaSNAC4-3D, and characterized the function of TaSNAC4-3A in plant drought tolerance. TaSNAC4 is highly expressed in seedling leaves, and expression is induced by various abiotic stresses. Transient expression and transactivation assays showed that TaSNAC4-3A is localized to the nucleus, and the C-terminal region has transcriptional activation activity. Overexpression of TaSNAC4-3A in Arabidopsis led to stimulated germination and root growth when exposed to salt and osmotic stresses, and drought stress tolerance was significantly increased in the TaSNAC4-3A transgenic lines. When compared to the control plants, the transgenic lines overexpressing TaSNAC4-3A exhibited reduced stomatal aperture size under drought stress, and therefore had lower water loss rates. In addition, the overexpression of TaSNAC4-3A led to abscisic acid (ABA) hypersensitivity at the root elongation and seed germination stages. Further transcriptomic analysis demonstrated that there was a significant up-regulation of stress responsive genes in the TaSNAC4-3A transgenic lines. Our findings have revealed the important role of TaSNAC4-3A in plant drought tolerance.

NAC转录因子（TFs）在植物非生物胁迫响应中起关键作用。但是，有关NAC TF的作用的信息在小麦（Triticum aestivum L.）中是有限的。在这项研究中，我们分离了三个小麦TaSNAC4同源基因TaSNAC4-3A，TaSNAC4-3B和TaSNAC4-3D，并表征了TaSNAC4-3A在植物抗旱性中的功能。TaSNAC4在幼苗叶片中高度表达，表达是由各种非生物胁迫诱导的。瞬时表达和反式激活分析表明，TaSNAC4-3A位于细胞核，并且C端区域具有转录激活活性。过度表达当暴露于盐和渗透胁迫下时，拟南芥中的TaSNAC4-3A导致刺激的发芽和根系生长，并且TaSNAC4-3A转基因品系中的干旱胁迫耐受性显着提高。与对照植物相比，过表达TaSNAC4-3A的转基因品系在干旱胁迫下表现出减小的气孔孔径，因此失水率更低。此外，TaSNAC4-3A的过表达导致根伸长和种子萌发阶段脱落酸（ABA）过敏。进一步的转录组分析表明，TaSNAC4-3A中的应激反应基因显着上调转基因品系。我们的发现揭示了TaSNAC4-3A在植物抗旱性中的重要作用。