Promoter reprogramming of melatonin biosynthetic networks for multi-stress climate-resilient crops

Climate change imposes increasingly complex and fluctuating biotic and abiotic stresses that threaten crop productivity. Melatonin (MT) is a multifunctional signaling molecule central to plant development, redox homeostasis, and stress adaptation, yet current strategies largely address MT-mediated tolerance under single stress conditions. Here, we synthesize evidence showing that diverse environmental stresses recurrently activate MT biosynthesis and signaling through partially overlapping but stress-specific regulatory networks, including reactive oxygen species, abscisic acid, and pathogen-triggered signaling. Exploiting the intrinsic environmental responsiveness of cis-regulatory elements, we propose a promoter reprogramming framework in which stress-responsive cis-elements are incorporated into promoters of MT biosynthesis genes using CRISPR/Cas-mediated genome editing. This strategy enables conditional, context-dependent induction of MT biosynthesis under stress, aligning endogenous defense with environmental demand while minimizing growth penalties. Collectively, this framework outlines a rational route toward developing climate-resilient smart crops under climate change.