ZmNAC032 and ZmNTL1 synergistically promote salt tolerance in maize by affecting K+/Na+ homeostasis and trehalose accumulation

The NAC (NAM, ATAF, and CUC) transcription factors include nuclear members and membrane members like NTL (NAC with Transmembrane motif 1-like). The objective of this study was to identify the mechanism by which NACs with different localizations synergistically regulate maize salt tolerance. Knockout, overexpression, and protein interaction studies showed that ZmNAC032 and ZmNTL1 form a module that mediates maize salt tolerance by regulating ion balance and soluble sugar accumulation. Combined ChIP, Y1H, and dual-luciferase reporter assays confirm that ZmNAC032 directly induces expression of the trehalose synthesis gene ZmTPSII.5.3 and the ion transport gene ZmHAK16a via direct interaction with the promoter cis -elements CCATCT and ACTGT, respectively. After salt stress, ZmNTL1 translocates to the nucleus and interacts with ZmNAC032, forming heterodimers that enhance ZmNAC032‑mediated transcriptional activation of ZmTPSII.5.3 and ZmHAK16a , suggesting synergistic regulation of ZmNAC032 and ZmNTL1 in maize. Double overexpression of ZmNTL1 and ZmNAC032 confers the highest salt tolerance, while double knockout confers the lowest, indicating their synergistic positive regulation in maize. This study reveals the molecular mechanism by which the transcriptional module mediated by ZmNAC032-ZmNTL1 regulates salt tolerance, which may be used to improve salt tolerance in maize via advanced breeding