Salicylic acid-responsive TaWRKY18-5A mediated salt tolerance via reprogramming of osmotic homeostasis and ROS...

Salicylic acid (SA) plays crucial roles in plant immunity and abiotic stress adaptation, yet its molecular mechanisms in regulating salt tolerance remain insufficiently characterized. This study reveals that exogenous SA application significantly improved wheat growth under salinity stress, while inhibition of SA biosynthesis using 1-aminobenzotriazole exacerbated salt-induced growth suppression. Through comprehensive transcriptomic analyses employing differential expression profiling, temporal dynamics assessment, and weighted gene co-expression network construction based on the complete telomere-to-telomere wheat genome assembly, we identified TaWRKY18-5A as a critical SA-responsive transcription factor governing salt tolerance mechanisms. Due to the technical difficulty and lengthy timeline for generating transgenic wheat (a Poaceae species), we overexpressed TaWRKY18-5A gene in rice (a Poaceae model plant) for functional characterization. Functional characterization demonstrated that TaWRKY18-5A overexpression enhanced osmotic adjustment through solute accumulation, reinforced antioxidant capacity via increased peroxidase activity, and potentially facilitates vacuolar sodium sequestration. Our findings establish SA as a positive regulator of wheat salt tolerance through transcriptional activation of TaWRKY18-5A-mediated stress adaptation pathways. This work provides valuable insights for optimizing SA-based agricultural practices and identifies a novel genetic target for improving crop resilience in saline environments.