Shade-induced metabolic reprogramming improves phytochemical profiles and antioxidant potential in Polygonatum cyrtonema

Light intensity is a crucial environmental factor affecting the growth and phytochemical composition of shade-adapted medicinal plants. Here, we investigated the physiological, transcriptomic, and metabolomic responses of Polygonatum cyrtonema under four shading levels. Moderate shading (60%) significantly enhanced biomass accumulation, photosynthetic efficiency, and antioxidant enzyme activities. In contrast, both mild and heavy shading suppressed growth and physiological performance. Integrated omics analyses revealed substantial transcriptional and metabolic reprogramming in response to shading, particularly in pathways related to carbohydrate metabolism, terpenoid biosynthesis, and phenylpropanoid metabolism. Moderate shading promoted sucrose accumulation and altered the expression of key genes involved in carbon allocation and secondary metabolism. Overall, our results demonstrate that moderate shading optimizes physiological performance and metabolic balance in P. cyrtonema . These findings provide mechanistic insights into light-regulated metabolic plasticity and offer practical guidance on optimizing shading management in the cultivation of shade-adapted medicinal plants. • Moderate shading (60%) maximized biomass production and photosynthetic efficiency. • Antioxidant defenses were strengthened through enhanced enzyme activities. • Multi-omics revealed shade-induced reprogramming of carbohydrate and phenylpropanoid metabolism. • Flavonoids and other bioactive metabolites with antioxidant activity were significantly enriched.