Screening and verification of EmMYB5 in flavonoids biosynthesis in Elaeagnus mollis dies kernel

Flavonoids are natural bioactive compounds with demonstrated health benefits in humans. Elaeagnus mollis Diels is a novel developing woody oil crop, and the flavonoids in E. mollis have attracted more attention. However, the composition content and biosynthesis mechanism of flavonoids in E. mollis kernel (EMF), the major application part, are still unclear. In this research, quantitative and multi-omics methods were orchestrated to explore dynamic and biosynthesis mechanism of flavonoids in EMF. The flavonoids content in EMF at nine harvest times (EMF1-EMF9) varied between 8.062 and 24.736 mg/g, peaking at EMF2. Multi-omics integration identified 59 core flavonoids biosynthesis genes, 711 DAMs, and 7312 DEGs. Enrichment analysis highlighted flavonoid, flavone and flavanol biosynthesis pathways. WGCNA analysis illustrated that the MEblue showed remarkable association with flavonoids quantity, and DEGs in this module significantly enriched in biosynthesis of secondary metabolites pathway. Correlation networks identified EmMYB5 and EmMYB105 as key regulators. Collectively, the functional characterization through transient overexpression and VIGS assays demonstrated that EmMYB5 acted as a negative regulator of flavonoids biosynthesis in EMF, with yeast-one-hybrid confirming EmMYB5 binding to the Em4CL promoter. The implementation of this study dissects the underlying mechanism of flavonoids biosynthesis in EMF, and also lays the foundation for further biofortified functional foods development of E. mollis . • 1 Flavonoids content fluctuated (8.06–24.74 mg/g) with kernel development in E. mollis . • 2 DAMs and DEGs orchestrated to guarantee flavonoids synthesis in E. mollis kernel. • 3 EmMYB5 acts as a negative regulator of flavonoids synthesis in E. mollis kernel.