Integrated Transcriptome and Metabolome Analysis Reveals Molecular Mechanisms of Flavonoid Biosynthesis During Camphora officinarum Leaf Development

Camphora officinarum Nees is a significant economic tree because of its aromatic, medicinal, and ornamental attributes. The diverse flavonoids present within the leaves of C. officinarum have been neglected for an extended period, hindering a comprehensive understanding of the molecular mechanisms responsible for color transformation and resistance to adverse environmental conditions. In this study, multi-omics analyses were conducted to systematically compare the relative contents of flavonoid metabolites and the expression profiles of flavonoid-related genes across three developmental stages of C. officinarum leaves. A total of 175 flavonoid compounds were detected via metabolomics, with flavonols being the most abundant. Through weighted gene co-expression network analysis, 25 key DEGs encoding CHS, DFR, FLS, ANS, F3′H, and LAR genes are predicted to be involved in anthocyanin biosynthesis for color change during leaf development. Notably, ten MYB, seven bHLH, and three ERF factors are potentially implicated in the regulation of key genes, underscoring their significant contributions to the color mechanisms underlying flavonoid biosynthesis. Other flavonoids, e.g., apigenin, isorhamnetin glycosides, sakuranetin, and sakuranin, may facilitate the adaptation of C. officinarum for protective purposes against adverse environmental conditions. These findings lay a theoretical foundation for resource exploration and the ornamentation improvement of C. officinarum.