Abstract
BACKGROUND: Olive (Olea europaea L.) oil is well-known commercial product worldwide for its nutritional and therapeutic properties. The molecular mechanisms underlying lipid variations in different olive cultivars remain unclear. METHODS: To investigate the molecular mechanism involved in lipid synthesis and metabolism, untargeted metabolome and RNA-Seq analyses were performed based on two varieties of olive fruits, i.e., Kalinjot (JZ) with low oil content and Coratina (KLD) with high oil content. RESULTS: Totally, 38 lipid compounds of 375 differentially accumulated metabolites (DAMs) were identified in JZ and KLD fruits, with 24 metabolites showing higher contents in KLD than those in JZ. Integrated transcriptome and metabolome analyses identified 48 differentially expressed genes (DEGs) associated with six lipid DAMs from JZ and KLD fruits. The contents of decanoic acid, sphinganine, and leukotriene D4 in KLD fruits were 2.33, 1.91, and 1.53 times greater than that of JZ fruits, respectively. In particular, two BCCP, one ACC, seven KAR, one EAR, one FATA and one SPT genes were observed involving to the content and quality of lipids in olive fruits. These DEGs were associated with the pathways of fatty acid biosynthesis, arachidonic acid metabolism, and limonene degradation. This study provides a strong theoretical and experimental foundation for further revealing the molecular mechanisms regulating lipid synthesis and metabolism in different olive cultivars.