Hormone-metabolism crosstalk in plants: an integrated signaling network coordinating growth and stress adaptation.

Plant growth, stress adaptation, and productivity depend on the continuous exchange of information between hormone signaling and metabolic networks. Although major phytohormones have been widely studied through their biosynthesis, receptors, and downstream transcriptional modules, these pathways are still often presented as linear systems. This view does not fully explain how plants integrate carbon status, nutrient availability, redox balance, cellular energy, and developmental signals under changing environments. In this review, we present plant hormone signaling and metabolism as a reciprocal regulatory network in which hormones reshape metabolic flux, while metabolites feedback to control hormone biosynthesis, transport, perception, degradation, and signal output. We synthesized evidence across salicylic acid, gibberellins, auxin, abscisic acid, strigolactones, ethylene, jasmonates, cytokinins, brassinosteroids, and melatonin, showing that sugars, amino acids, organic acids, lipid derivatives, sulfur metabolites, and redox signals act as shared regulatory nodes. This integrated perspective reveals that core metabolic signals such as sucrose, trehalose-6-phosphate, 2-oxoglutarate, citrate, malate, reactive oxygen species, glutathione, ascorbate, cysteine, and tryptophan coordinate multiple hormone pathways across tissues, developmental stages, and stress contexts. We further highlight emerging tools, including hormone atlases, live biosensors, spatial omics, single-cell omics, isotope tracing, genome editing, and computational network modeling, as essential approaches for moving from descriptive pathway maps to predictive systems biology. By defining hormone metabolism crosstalk as a central principle in plant biochemistry and physiology, this review provides a conceptual framework for identifying engineering targets that can improve crop resilience, nutrient use efficiency, and growth stress balance under future agricultural conditions.