Integrated Metabolomics and Transcriptomics Provided Novel Insights into the Biosynthetic Regulation of Phenolic Compounds in Vitis heyneana Roem. et Schult. var. adenoclada (Hand.-Mazz.)

Vitis heyneana Roem. et Schult. var. adenoclada (Hand.-Mazz.) is an important wild grapevine resource with unique berry traits and wine quality characteristics; yet the molecular mechanisms governing its phenolic biosynthesis remain to be further elucidated compared with cultivated Vitis vinifera. This study aimed to systematically characterize the transcriptional and metabolic regulation of phenolic compound accumulation in V. heyneana var. adenoclada using integrated metabolomics and transcriptomics. At the metabolic level, V. heyneana var. adenoclada exhibited significantly higher contents of phenolic acids (caffeic and ferulic acids), resveratrol, flavonols (quercetin and myricetin), flavan-3-ols (catechin and epicatechin), and anthocyanin diglucosides compared with V. vinifera cv. Cabernet Sauvignon. The two tested V. heyneana varieties showed distinct developmental accumulation profiles: Guiheizhenzhu No. 6 accumulated more ferulic acid, resveratrol, myricetin, and anthocyanins at maturity, whereas Yeniang No. 2 showed higher quercetin and flavan-3-ols at the green stage. Integrated multi-omics correlation analyses revealed that the elevated phenolic content is driven by the coordinated upregulation of key structural genes mediated by a complex MYB regulatory network. Specifically, MYB12 (MYBF1) positively correlated with COMT, CHI, DFR, and LAR. MYB5, MYBS3, and MYB61 promoted quercetin synthesis by activating FLS. MYB06, MYB4, and MYB36 enhanced STS transcription to drive resveratrol biosynthesis, whereas MYB1 and MYB5 cooperatively regulated UFGT, 5GT, and GST4, facilitating efficient synthesis and transport of anthocyanin diglucosides. These findings provide comprehensive mechanistic insights into phenolic metabolism in V. heyneana var. adenoclada and establish a valuable theoretical foundation for improving the flavor quality and regional utilization of wild grape wines.