Genome of wild olive and the evolution of oil biosynthesis
Genome of wild olive and the evolution of oil biosynthesis
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DOI：
10.1073/pnas.1708621114
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发表时间：
2017-10-01
影响因子：
11.1
通讯作者：
Van de Peer, Yves
中科院分区：
文献类型：
--
作者：
Unver, Turgay;Wu, Zhangyan;Van de Peer, Yves
在这里，我们提出的基因组序列和注释的野生橄榄树（油橄榄欧洲变种。这是一种被称为橄榄树（oleaster）的植物，被认为是栽培橄榄树的祖先。预测有超过50，000个蛋白质编码基因，其中大部分可以锚定到通过新构建的遗传图谱获得的23个假染色体上。沙枣基因组包含两个Oleaceae谱系特定的古多倍体事件的签名，日期类似于28和类似于59 Mya。这些事件有助于在石油生物合成中发挥重要作用的基因和基因家族的扩展和新功能化。油生物合成途径基因的功能分歧，如FAD 2，SACPD，ESTA，和ACPTE，重复后，已负责与芝麻，一个密切相关的油料作物相比，橄榄中产生的油酸和亚油酸的差异积累。重复的沙枣FAD2基因受到来自富含转座元件区域的siRNA的调控，导致FAD2基因表达水平受到抑制。此外，SACPD基因家族成员的新功能化导致SACPD 2、3、5和7的表达增加，从而导致硬脂酸的去饱和度增加。总之，FAD 2表达减少和SACPD表达增加可能解释了橄榄中异常高水平的油酸的积累。因此，沙枣基因组提供了重要的见解，石油生物合成的演变，将是一个宝贵的资源，油料作物基因组学。
Here we present the genome sequence and annotation of the wild olive tree (Olea europaea var. sylvestris), called oleaster, which is considered an ancestor of cultivated olive trees. More than 50,000 protein-coding genes were predicted, a majority of which could be anchored to 23 pseudochromosomes obtained through a newly constructed genetic map. The oleaster genome contains signatures of two Oleaceae lineage-specific paleopolyploidy events, dated at similar to 28 and similar to 59 Mya. These events contributed to the expansion and neo-functionalization of genes and gene families that play important roles in oil biosynthesis. The functional divergence of oil biosynthesis pathway genes, such as FAD2, SACPD, EAR, and ACPTE, following duplication, has been responsible for the differential accumulation of oleic and linoleic acids produced in olive compared with sesame, a closely related oil crop. Duplicated oleaster FAD2 genes are regulated by an siRNA derived from a transposable element-rich region, leading to suppressed levels of FAD2 gene expression. Additionally, neofunctionalization of members of the SACPD gene family has led to increased expression of SACPD2,3, 5, and 7, consequently resulting in an increased desaturation of steric acid. Taken together, decreased FAD2 expression and increased SACPD expression likely explain the accumulation of exceptionally high levels of oleic acid in olive. The oleaster genome thus provides important insights into the evolution of oil biosynthesis and will be a valuable resource for oil crop genomics.