Light and nutrient cues elicit metabolic reprogramming by targeting carbon fixation, redox balance, and ATP homeostasis in Agastache rugosa.

Main conclusion: The study uncovers how Agastache rugosa coordinates carbon fixation, redox balance, and ATP homeostasis via distinct metabolic strategies optimized for different light and nutrient conditions. This study explores the metabolic adaptations of Agastache rugosa (Fisch. & C.A.Mey.) Kuntze in varying light and nutrient conditions, focusing on the coordination between photosynthetic and respiratory pathways. Plants were grown under two light levels (high light, 0% shade; low-light, 50% shade) and four nutrient treatments (NPK1, 40 mg kg^-1; NPK2, 80 mg kg^-1; NPK3, 120 mg kg^-1; NPK4, 160 mg kg^-1) and key metabolic parameters were analyzed. High-light plants had peak carbonic anhydrase activity (5.17 ± 0.26 U g^-1 FW) at NPK2, optimizing carbon fixation and redox balance with 20.6% and 12.8% higher NADP⁺/NADPH and NAD⁺/NADH ratios, each. Low-light plants upregulated PEPC (+110%), and PEPCK (+34%) at NPK4, displaying enhanced anaplerotic carbon fixation. Despite lower respiratory activity, (NADH-UQ, -50%; COX, -46%), plants under low-light had tenfold higher ATP at NPK3 through reduced consumption. Principal component and hierarchical cluster analyses (> 60% similarity) revealed distinct metabolic strategies between light treatments. Strong correlations among photosynthetic, respiratory, and redox parameters (r > 0.7, P < 0.001) indicated metabolic integration via shared regulatory networks. Our findings reveal the metabolic plasticity of A. rugosa, offering insights into plant adaptation with implications for cultivation. Moreover, multivariate analyses unveiled complex regulatory networks coordinating energy metabolism, highlighting the metabolic reprogramming employed by A. rugosa to maintain energetic and redox balance under dynamic environmental conditions.