Researchers report the draft genome sequence of wild olive trees. Cultivated varieties of olive trees are thought to have stemmed from oleaster (Olea europea var. sylvestris), the wild precursor, in Asia Minor before reaching the Mediterranean, which serves as a home to an array of olive varieties. Yves Van de Peer and colleagues assembled and annotated the 1.48 Gbp draft genome sequence of oleaster, revealing signatures of ancient genetic events related to olive oil biosynthesis. Harboring an estimated 50,684 protein-coding genes, the oleaster genome exhibits signs of multiple ancient genome duplication events, notable among which are two events specific to the oleaster lineage that occurred around 28 and 59 million years ago. The pair of duplication events led to the expansion and functional diversification of genes involved in oil biosynthesis, potentially explaining the high content of oleic acid (75%), a major component in olive oil, compared with linoleic acid (5.5%); by comparison, the closely related sesame seed oil contains around 40% of each fatty acid. Reduced expression of FAD2 genes that results from naturally occurring RNA interference and heightened expression of SACPD genes through ancient gene duplication might together account for olive oil's high oleic acid content. According to the authors, the draft genome sequence yields insights into the evolution of oil biosynthesis that could be applied to improve olive oil production.
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Article #17-08621: "Genome of wild olive and the evolution of oil biosynthesis," by Turgay Unver et al.
MEDIA CONTACT: Yves Van de Peer, VIB-UGENT, Ghent, BELGIUM; tel: +32-9-3313807; e-mail: <yves.vandepeer@psb.vib-ugent.be>; Turgay Unver, Dokuz Eylul University, Izmir, TURKEY; tel: +90-5062778442; e-mail: <turgayunver@icloud.com>
Journal
Proceedings of the National Academy of Sciences