Integrated Analysis Reveals Functional Ingredients Biosynthesis and Regulatory Mechanisms in Elaeagnus mollis Diels...

Elaeagnus mollis Diels is a newly developed woody oil crop, and the biosynthesis and regulatory mechanism underlying functional and nutritional ingredients in leaf have long been neglected. In the present study, we integrated quantification and multi-omics analysis to unravel the biosynthesis pathway and regulatory mechanism of flavonoids, phenols, and terpenoids, which all held substantial nutritional significance in E. mollis leaf (EML). Quantification results indicated that the contents of three ingredients increased with EML development and showed fluctuations before senescence, with the highest value as 27.45 mg/g for flavonoids and 17.486 mg/g for phenols. The accumulation of these functional ingredients contributed primarily to the in vitro antioxidant capacity, which directly reflected the potential nutritional utilization of EML. Comprehensive analysis of multi-omics data identified 14, 19, and 37 DEGs, as well as 32, 21, and 52 DAMs involved in the biosynthesis pathway of flavonoids, phenols, and terpenoids, respectively. Co-expression network construction revealed that transcription factors from EmNACs, EmMYBs, and EmDREBs may regulate the biosynthesis of flavonoids, phenols, and terpenoids. The specific positive regulatory roles of EmNAC014 and EmMYB15 in flavonoids and phenols biosynthesis were verified with in vivo transient overexpression and VIGS analysis. Furthermore, some potential coregulation factors simultaneously participating in various biosynthesis pathways were identified. This study not only expands the acknowledgement of functional ingredients biosynthesis and accumulation pattern, but also provides vital biomarkers that can be targeted for regulating the contents to enhance the nutritional value and utilization of E. mollis leaf.