Areca catechu L., of the
Arecaceae
family, is widely distributed in tropical Asia. In A. catechu, the extracts and compounds, including
flavonoids, have various pharmacological activities. Although there
are many studies of flavonoids, the molecular mechanism of their biosynthesis
and regulation remains unclear in A. catechu. In this study, 331 metabolites were identified from the root, stem,
and leaf of A. catechu using untargeted
metabolomics, including 107 flavonoids, 71 lipids, 44 amino acids
and derivatives, and 33 alkaloids. The transcriptome analysis identified
6119 differentially expressed genes, and some were enriched in the
flavonoid pathway. To analyze the biosynthetic mechanism of the metabolic
differences in A. catechu tissues,
36 genes were identified through combined transcriptomic and metabolomic
analysis, in which glycosyltransferase genes Acat_15g017010 and Acat_16g013670 were annotated as being involved
in the glycosylation of kaempferol and chrysin by their expression
and in vitro activities. Flavonoid biosynthesis could be regulated
by the transcription factors, AcMYB5 and AcMYB194. This study laid a foundation for further research
on the flavonoid biosynthetic pathway of A. catechu.