Integrated Transcriptomic and Targeted Metabolomic Analyses Elucidate the Molecular Mechanism Underlying Dihydromyricetin Synthesis in .

(Hand.-Mazz.) J. Wen & Z. L. Nie is a medicinal and edible plant with a high dihydromyricetin (DHM) content in its bud tips. Vine tea made from its bud tips has served as a health tea and Chinese herbal medicine for nearly 700 years. However, the molecular mechanisms underlying the high DHM content in bud tips remain inadequately elucidated. This study conducted qualitative and quantitative analyses of bud tip flavonoids utilizing HPLC and targeted metabolomics. Core genes influencing the substantial synthesis of DHM in were identified through integrated transcriptome and metabolome analyses. The results revealed that 65 flavonoid metabolites were detected in bud tips, with DHM as the predominant flavonoid (37.5%), followed by myricetin (0.144%) and taxifolin (0.141%). Correlation analysis revealed a significant positive correlation between expression and DHM content. Co-expression analysis and qRT-PCR validation demonstrated a significant positive correlation between NgMYB71 and , with consistent expression trends across three periods and four tissues. Consequently, and were identified as core genes influencing the substantial synthesis of DHM in . Elevated NgMYB71 expression in bud tips induced high expression, facilitating extensive DHM synthesis in bud tips. Molecular docking analysis revealed that NgF3'5'H3 had a strong binding affinity for taxifolin. was the pivotal core node gene in the dihydromyricetin biosynthesis pathway in and was highly expressed in bud tips. The strong specific binding of NgF3'5'H3 to dihydromyricetin precursor metabolites catalyzed their conversion into DHM, resulting in higher DHM contents in bud tips than in other tissues or plants. This study aimed to elucidate the molecular mechanisms underlying the substantial synthesis of DHM in , providing a theoretical foundation for enhancing DHM production and developing resources.