Change in Oil Composition and the Major Fatty Acids and Triacylglycerol Biosynthesis Genes in Drupe of Selected Olive Cultivars during Growing Season; A Two Years Study

Abstract

AbstractUncovering the relationships between the content and compositions of olive oil, environmental factor, and developmental stages can lead to the effective cultivation choices and maximizing productivity. Fatty acid contents of 4 olive cultivars are screened at 5 developmental stages during 2 cropping seasons. Moreover, the transcript abundance of 4 fatty acids and triacylglycerol biosynthesis genes are evaluated in 2 cultivars displaying distinct oil content and composition. Thought, all studied cultivars display a rise in oil content and a decline in oleic/linoleic acid as maturity advances, the fatty acid content, however changes in a cultivar‐dependent manner. In contrast to other cultivars, “Mari” shows an increasing trend for oleic acid and fruit RH, and steady state pattern for linoleic acid during fruit development. All these characteristics result in a unique oil quality in “Mari”. Accordingly, there are slight differences in the oil related‐attributes in 2 cropping years at different sampling dates which are also cultivar dependent. The expression patterns of oil biosynthesis genes are well‐paralleled with oil accumulation and compositions in the studied olive cultivars; as OeSAD2 and OeDGAT2 experience a significant higher expression in “Mari”, while “Shengeh” has higher levels for OeFAD2‐2 and OeDGAT1 during most sampling times.Practical Applications: According to these data, the lower expression of OeFAD2‐2, as well as, substantially higher expression of OeSAD2 and OeDGAT2 are suggested as the major players for higher oil and oleic acid production in “Mari”. Results obtained from this study improve knowledge about oil biosynthesis in olive drupe in relation to fruit ripening and environmental factors. These data are useful for both growers and experts enabling them to make more appropriate planting and harvest decisions, as well as, to design suitable breeding programs to achieve olive improvement objectives.