Multi-omics analyses of Dracocephalum moldavica L. reveal two flavonoid glycosyltransferases in tilianin biosynthesis

BACKGROUND: To explore reference genome of Dracocephalum moldavica L. and provide a basis for the study of the mechanism of tilianin biosynthesis. RESULTS: We present telomere-to-telomere (T2T) genome assembly with the size of 255.61 Mb and a contig N50 length of 58.45 Mb. By integrating multi-omics resources, we identified two UDP- glycosyltransferases, Dm7GlcT1 and Dm7GlcT2, catalyzing the glucosylation of acacetin at 7-OH, which was the final step in tilianin biosynthetic pathway. The findings from the in vitro enzyme activity assay and qRT-PCR analysis further indicate that Dm7GlcT1 may be responsible for catalyzing tilianin biosynthesis in stems and flowers, whereas glucosylation mediated by Dm7GlcT2 could occur in all tissues. CONCLUSION: Our work presents the first T2T genome assembly of D. moldavica and identified two key UDP- glycosyltransferases associated with tilianin biosynthesis, which provided a valuable reference for further metabolic network construction of tilianin biosynthesis and genetic improvement of D. moldavica with high tilianin product.