Bombarely Aureliano, Doulis Andreas G, Lambrou Katerina K, Zioutis Christos, Margaritis Evi, Koubouris Georgios
Department of Bioscience, Universita degli Studi di Milano, 20133 Milan, Italy.
Instituto de Biologıa Molecular y Celular de Plantas (IBMCP), UPV-CSIC, 46022 Valencia, Spain.
Plants (Basel). 2021 Nov 4;10(11):2374. doi: 10.3390/plants10112374.
The olive tree of Vouves in Crete, is considered the oldest producing olive tree in the world with an estimated age exceeding 4000 years. In the present study, we sequenced two samples (from the bottom and the top of the tree) to elucidate the genetic relation of this ancient tree with other olive cvs as well as to gain some insights about its origin. Our results showed that both samples have different genetic origins, proving that this ancient tree has been grafted at least one time. On the basis of whole genome sequences the sample from the top of the Vouves tree showed relation of the same order than half-siblings to one accession corresponding to the present-day Greek cv 'Mastoidis'. Nevertheless, in the framework of a microsatellite analysis it was found to cluster with the 'Mastoidis' samples. The Vouves rootstock (bottom sample) showed a clear grouping with the oleaster samples in a similar way to that of 'Megaritiki' Greek cv although it does not show any signal of introgression from them. The genomic analyses did not show a strong relation of this sample with the present-day Greek cvs analyzed in this study so it cannot be proved that it has been used as a source for cultivated olive tree populations represented by available genome sequences. Nevertheless, on the basis of microsatellite analyses, the Vouves rootstock showed affinity with two present-day Greek cvs, one "ancient" rootstock from continental Greece as well as monumental trees from Cyprus. The analysis of the impact of the variants in the gene space revealed an enrichment of genes associated to pathways related with carbohydrate and amino acid metabolism. This is in agreement with what has been found before in the sweep regions related with the process of domestication. The absence of oleaster gene flow, its old age and its variant profile, similar to other cultivated populations, makes it an excellent reference point for domestication studies.
克里特岛沃夫斯的橄榄树被认为是世界上最古老的产果橄榄树，估计树龄超过4000年。在本研究中，我们对两个样本（分别取自树的底部和顶部）进行了测序，以阐明这棵古树与其他橄榄品种的遗传关系，并深入了解其起源。我们的结果表明，两个样本具有不同的遗传起源，证明这棵古树至少被嫁接过一次。基于全基因组序列，沃夫斯树顶部的样本与现今希腊品种“Mastoidis”的一个样本显示出与半同胞相同程度的亲缘关系。然而，在微卫星分析框架下，它被发现与“Mastoidis”样本聚类。沃夫斯砧木（底部样本）与油橄榄样本明显聚类，方式类似于希腊品种“Megaritiki”，尽管它没有显示出来自它们的任何渐渗信号。基因组分析没有显示该样本与本研究中分析的现今希腊品种有很强的关系，因此无法证明它被用作现有基因组序列所代表的栽培橄榄树种群的来源。然而，基于微卫星分析，沃夫斯砧木与两个现今希腊品种、一个来自希腊大陆的“古老”砧木以及塞浦路斯的纪念树有亲缘关系。对基因空间中变异影响的分析揭示了与碳水化合物和氨基酸代谢相关途径的基因富集。这与之前在与驯化过程相关的扫描区域中发现的结果一致。没有油橄榄基因流、其树龄以及其变异谱与其他栽培种群相似，使其成为驯化研究的绝佳参考点。
