Olive-Tree Genome Sequencing: Towards a Better Understanding of Oil Biosynthesis

The olive tree (Olea europaea) is one of the main cultural, characteristic and economically important trees, which is broadly grown especially in the Mediterranean Basin, where 97% of the worlds’ total olive production is produced. There is a broad variety of olive-based products (food, cosmetics, health, etc.), that together with olive oil provide important income for the people living in those regions. In addition to the environmental conditions, the chemical composition, organoleptic characteristics and olive oil yield depend on the olive-tree cultivar. Some of them are especially efficient for olive-oil production, like Ayvalik. Oleaster or wild-type olive trees (Olea europaea var. sylvestris) produce small olive fruits (‘acebuchinas’), with lower olive-oil yields but interesting chemical composition, with interesting organoleptic and health benefits, like a high antioxidant activity. In 2016, the genome of the domesticated cultivar of olive (cv. Farga) has released. A year later, the genome of the wild type cultivar of olive tree (Olea europaea var. sylvestris) was shotgun-sequenced with a coverage of 220× generating 515.7 Gbp of data. In addition to the genomics data, transcriptome sequences of wild olive revealed key genes related to oil metabolism. Here, we summarize recent findings regarding the olive genome, like its assembly and annotation, analysis of miRNAs, repetitive sequences, transposons, and tandem repeats, the evolution of the olive genome, and oil biosynthesis pathway.