Transcriptome and Metabolomic Analyses Reveal Tissue-Specific Glycosylation of Phenylpropanoids and Flavonoids in Toxicodendron vernicifluum.

Toxicodendron vernicifluum (Stokes) F. A. Barkley is a tree species used primarily for lacquer production. Our study utilized transcriptome and metabolomic analysis to investigate the biosynthesis of phenylpropanoids and flavonoids, specifically the glycosylated forms, in T. vernicifluum roots, stems, and leaves. HPLC-QTOF-MS/MS identified 186 compounds, with tissue-specific distributions revealed by PCA. Flavonoids and phenylpropanoids glycosides were significantly more abundant in leaves compared with roots and stems. Full-length sequencing uncovered 17,266 transcripts in T. vernicifluum. Gene expression analysis showed higher activity of phenylpropanoid and flavonoid biosynthesis pathways in leaves. Certain genes, such as CYP73A, 4CL, CRR, CYP84A/F5H, and CYP93C, displayed associations with compound content distributions. Root tissue exhibited a higher concentration of isoflavones. Notably, glycosyltransferase expression demonstrated significant correlations with glycosylated compounds' content. Biochemical validation confirmed the involvement of TvPB_c0_g2904, encoding a UDP-glucosyltransferase, in genistin biosynthesis in T. vernicifluum.