Fatty acid profiles and differential genes expression in Tunisian olive cultivars: a study of fruit ripening and quality attributes

The olive tree is a key agricultural crop in the Mediterranean region. In spite of its economic importance, genes involved in oil production and quality are not investigated entirely. In this study, the tendency of oil amount, fatty acid (FA) profile and gene-expression levels of the principal olive cultivars in Tunisia; Chemlali and Chetoui were examined during different growth periods (ranging from 80 to 190 days after flowering) across various tissues. The two cultivars exhibited similar oil accumulation patterns but moderate differentiation in FA composition. Real time PCR was carried out and the factor elongation1 gene (EF-1a) was chosen as control gene for internal control. Results demonstrated that Chetoui had the highest levels of expression of the OeSAD gene, this pattern closely aligned with the accumulation of oleic acid and oil during mesocarp development. In the case of oleate desaturases, a declining trend in OeFAD2-1 and OeFAD6 transcript levels was observed, while OeFAD2-2 expression exhibited an increasing pattern throughout mesocarp maturation. In conclusion, our findings provided primary information on genes involved on FA increase during fruit maturation and then it reveals some primary data related to crop stress resistance.