Adenylate Cyclase-Mediated cAMP Elevation Enhances Salt Stress Tolerance and Disease Resistance via Transcriptional and ER Stress Regulatory Networks in Arabidopsis thaliana

Background: Cyclic AMP (cAMP) is a conserved second messenger with established roles in microbes and animals, but its functions in plants remain poorly understood. Engineered adenylate cyclase (AC) activity can elevate cAMP and influence signaling pathways. This study investigates how sustained cAMP elevation affects transcriptomic networks and salt stress tolerance in Arabidopsis thaliana.Methods: A glucocorticoid-inducible AC transgene (pTA7001-AC) was used to increase endogenous cAMP in col-0 seedlings. RNA-Seq was performed at 1, 3, 12, 24, and 72 h post-induction. Genes consistently regulated across all time points were defined as constitutive cAMP-responsive genes (CRGs) or anchor CRGs. GO, KEGG, GSEA, k-means clustering, and mapped cAMP-regulated pathways. Salt stress assays (100 mM NaCl) and HPLC quantified physiological responses and cAMP levels.Results: A total of 292 CRGs were identified, enriched for transcription factor activity, ER protein folding, phytohormone metabolism, and stress responses. K-means clustering revealed key CRG clusters emphasizing transcriptional regulation and protein quality control. Anchor CRGs, including stress-responsive genes and transcription factors acted as game changer. AC transgenic seedlings exhibited enhanced root growth and reduced sensitivity to prolonged salinity, along with enhanced disease resistance against Pst DC3000, with HPLC confirming elevated cAMP levels.Conclusion: Elevated cAMP orchestrates transcriptional, hormonal, and protein-folding networks, improving salt stress tolerance in Arabidopsis. These results position cAMP as a central integrator of plant stress responses and provide a mechanistic foundation for engineering abiotic stress-resilient crops.