ZmSNAC1 cooperates with its interaction partner ZmNAC19 and ZmCAR11 to regulate drought tolerance in maize

Drought environment series impacts global maize production and induces drought stress responses. NAC (NAM, ATAF, and CUC) transcription factors play important roles in various cellular processes, including plant growth, development and response to drought. In our previous study, a drought responsive NAC gene ZmSNAC1 was identified and confirmed as a positive regulator in drought stress response. However, the detailed molecular regulation mechanism of ZmSNAC1 for drought stress tolerance remains largely unknown. In this study, we further explore the candidate downstream target genes of ZmSNAC1 using RNA-Seq and ChIP-Seq screening strategy, and demonstrate that ZmSNAC1 directly bind to the CGTA core cis-element in the promoter of drought inducible genes ZmATL2C and ZmGPT2 to activate their expression. Functional analysis indicates that the E3 ubiquitin ligase RING-finger gene ZmATL2C significantly upregulate its expression and improve drought stress tolerance. Furthermore, yeast two-hybrid, BIFC, CoIP experiments show that ZmSNAC1 physically interact with another NAC family member ZmNAC19 and a C2-domain ABA-related protein ZmCAR11 to form a complex, thereby enhancing the expression of ZmATL2C synergistically, then regulate root development, improve water uptake efficiency and drought resilience. We also characterize ZmSNAC1 interacting protein ZmCAR11 and prove that it confers improved drought tolerance in maize. Collectively, our study reveals that ZmSNAC1 orchestrates protein interactions and the expression of downstream target genes to optimize root architecture and stress adaptation, ultimately offering valuable molecular mechanisms for developing maize engineering varieties with enhanced drought resistance.