Combined non-targeted metabolomic and transcriptomic analysis explains the biosynthetic pathway and differential accumulation of chlorogenic acid in the Liriodendron petal

Petal secondary metabolites can affect pollinator selection and invasion of pathogenic microorganisms to change the adaptability to the environment. Meanwhile, the active components in petal are widely used in many aspects of human society. At present, research into bioactive compounds in Liriodendron have mainly focused on bark, leaf and root tissues, with few studies systematically studying the differences in secondary metabolite content of petals coming from different Liriodendron accessions. By combining untargeted LC–MS metabolome analysis with analysis of the Liriodendron petal transcriptome, the biosynthetic pathway of activity in Liriodendron petals was studied, and the 6097 different accumulated metabolites were identified in different Liriodendron. These differentially accumulated metabolites (DAMs) are synthesized through multiple secondary metabolic pathways, with a strong enrichment for flavonoid and phenylpropanoid biosynthetic compounds, suggesting that these active substances may be potentially valid medicinal components. In this study, the accumulation of chlorogenic acid (CGA) was increased in the petals of L. chinense. In addition, the chlorogenic acid synthesis pathway, which is mainly involved in the regulation of multiple CYP98A enzymes. These results reveal differential accumulation of secondary metabolites and potential medicinal ingredients in Liriodendron petals and thus provide a basis for further effective utilization of petals.