Center for Advanced Studies in Olive Grove and Olive Oils, Department of Experimental Biology, University. Jaén, Jaén, 23071, Spain.
Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany.
Plant Genome. 2020 Mar;13(1):e20010. doi: 10.1002/tpg2.20010. Epub 2020 Mar 27.
The primary domestication of olive (Olea europaea L.) in the Levant dates back to the Neolithic period, around 6,000-5,500 BC, as some archeological remains attest. Cultivated olive trees are reproduced clonally, with sexual crosses being the sporadic events that drive the development of new varieties. In order to determine the genomic changes which have occurred in a modern olive cultivar, the genome of the Picual cultivar, one of the most popular olive varieties, was sequenced. Additional 40 cultivated and 10 wild accessions were re-sequenced to elucidate the evolution of the olive genome during the domestication process. It was found that the genome of the 'Picual' cultivar contains 79,667 gene models, of which 78,079 were protein-coding genes and 1,588 were tRNA. Population analyses support two independent events in olive domestication, including an early possible genetic bottleneck. Despite genetic bottlenecks, cultivated accessions showed a high genetic diversity driven by the activation of transposable elements (TE). A high TE gene expression was observed in presently cultivated olives, which suggests a current activity of TEs in domesticated olives. Several TEs families were expanded in the last 5,000 or 6,000 years and produced insertions near genes that may have been involved in selected traits during domestication as reproduction, photosynthesis, seed development, and oil production. Therefore, a great genetic variability has been found in cultivated olive as a result of a significant activation of TEs during the domestication process.
橄榄(Olea europaea L.)最初在黎凡特地区被驯化的时间可以追溯到新石器时代,大约在公元前 6000-5500 年,一些考古遗迹可以证明这一点。栽培橄榄树通过无性繁殖进行繁殖,有性杂交是驱动新品种发展的偶发事件。为了确定现代橄榄品种中发生的基因组变化,对 Picual 品种(最受欢迎的橄榄品种之一)的基因组进行了测序。为了阐明橄榄在驯化过程中的基因组进化,还对另外 40 个栽培品种和 10 个野生品种进行了重测序。研究发现,'Picual'品种的基因组包含 79667 个基因模型,其中 78079 个是蛋白质编码基因,1588 个是 tRNA。群体分析支持橄榄驯化过程中发生了两次独立的事件,包括早期可能存在遗传瓶颈。尽管存在遗传瓶颈,但栽培品种表现出由转座元件(TE)激活引起的高遗传多样性。目前栽培橄榄中观察到高 TE 基因表达,这表明驯化橄榄中 TE 目前处于活跃状态。在过去的 5000 年或 6000 年中,几个 TE 家族发生了扩张,并在与生殖、光合作用、种子发育和油脂生产等驯化过程中涉及的选择性状相关的基因附近产生了插入。因此,由于在驯化过程中转座元件的显著激活,栽培橄榄中发现了很大的遗传变异性。