[Effect of light quality on secondary metabolite accumulation in seedling-stage of Pseudostellaria heterophylla and its metabolomic analysis].

The present study aimed to elucidate the effects of different light qualities(red, blue, and white light) on the accumulation of secondary metabolites in Pseudostellaria heterophylla and to identify key metabolites regulated by light signaling. Widely targeted metabolomics was employed to analyze metabolic profile changes in tuberous roots subjected to red, blue, and white light treatments, followed by Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis. A total of 2 139 metabolites were detected, spanning 12 classes, including flavonoids, alkaloids, phenolic acids, amino acids, and terpenoids. Principal component analysis and hierarchical clustering analysis revealed significant differences in metabolic patterns among the different light quality treatments. Differential metabolite analysis indicated that the red light vs white light and blue light vs white light comparisons were dominated by downregulated metabolites, whereas the blue light vs red light comparison was dominated by upregulated metabolites. Blue light markedly enhanced the accumulation of multiple functional metabolites, particularly flavonoids and phenolic acids, such as luteolin-7-O-glucoside, kaempferol-3-O-glucoside, naringenin-7-O-glucoside, quercetin-3-O-rutinoside, 3,5-dicaffeoylquinic acid, and ferulic acid, indicating its enhancing effect on antioxidant and pharmacologically active compounds. In addition, blue light significantly increased the levels of flavanols and anthocyanins, including catechin gallate and pelargonidin-3-O-(6″-caffeoyl)sophoroside. KEGG pathway analysis showed that blue light treatment was significantly enriched in several representative secondary-metabolism pathways, including flavonoid biosynthesis, phenolic acid metabolism, and terpenoid biosynthesis. These findings indicate that blue light effectively induces the synthesis and accumulation of various representative bioactive components in P. heterophylla, providing a theoretical basis for improving its medicinal quality and regulating its light-growth environment.