Integrative transcriptomic and metabolomic analyses provide molecular insights into blue light-induced flavonoid accumulation in Eucommia ulmoides callus
摘要
The light environment is a key factor regulating plant secondary metabolism. This study integrated transcriptomics and metabolomics to investigate the effects of different intensities of blue light (450–470 nm, 50 and 100 µmol·m⁻²·s⁻¹) on the accumulation of flavonoid compounds and the underlying regulatory networks in Eucommia ulmoides callus. Compared with the dark control group, blue light treatments significantly increased the total flavonoid content. Widely targeted metabolomics identified 115 flavonoid compounds. Notably, under high-intensity blue light (100 µmol·m⁻²·s⁻¹), we observed a profound metabolic flux shift: the depletion of free flavonoid precursors accompanied by the massive accumulation of flavonoid glycosides, with hyperin and quercetin-7-O-glucoside exhibiting the most dramatic increases (Log2FC > 7.0). Transcriptomic analysis identified 4821 differentially expressed genes, suggesting that this glycosylation-directed metabolic shift was highly correlated with the significant upregulation of key structural genes (e.g., CHS, FLS, and ANS). Furthermore, the significant upregulation of the light receptor CRY and transcription factor HY5 points to a potential regulatory module involving downstream MYB and bHLH factors. Distinct from previous generalized studies, our integrative multi-omics approach proposes a specific regulatory framework in Eucommia ulmoides callus, where blue light is associated with both flavonoid biosynthesis and the extensive glycosylation of these compounds. This study provides new molecular insights into light-regulated plant secondary metabolism and proposes a model for optimizing the high-yield production of stable, bioactive flavonoid glycosides in vitro.