Sun Ting, Renner Susanne S, Xu Yuxing, Qin Yan, Wu Jianqiang, Sun Guiling
Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, Kaifeng 475004, China.
Sci Rep. 2016 Jul 25;6:30192. doi: 10.1038/srep30192.
A growing body of evidence is pointing to an important role of horizontal gene transfer (HGT) in the evolution of higher plants. However, reports of HGTs of transposable elements (TEs) in plants are still scarce, and only one case is known of a class II transposon horizontally transferred between grasses. To investigate possible TE transfers in dicots, we performed transcriptome screening in the obligate root parasite Phelipanche aegyptiaca (Orobanchaceae), data-mining in the draft genome assemblies of four other Orobanchaceae, gene cloning, gene annotation in species with genomic information, and a molecular phylogenetic analysis. We discovered that the broomrape genera Phelipanche and Orobanche acquired two related nuclear genes (christened BO transposase genes), a new group of the hAT superfamily of class II transposons, from Asian Sisymbrieae or a closely related tribe of Brassicaceae, by HGT. The collinearity of the flanking genes, lack of a classic border structure, and low expression levels suggest that BO transposase genes cannot transpose in Brassicaceae, whereas they are highly expressed in P. aegyptiaca.
越来越多的证据表明水平基因转移（HGT）在高等植物进化中起着重要作用。然而，关于植物中转座元件（TEs）水平基因转移的报道仍然很少，并且已知只有一例II类转座子在禾本科植物之间进行水平转移。为了研究双子叶植物中可能的TE转移，我们对专性根寄生植物埃及列当（列当科）进行了转录组筛选，在其他四种列当科植物的基因组草图组装中进行数据挖掘，进行基因克隆，在有基因组信息的物种中进行基因注释，并进行分子系统发育分析。我们发现列当属和肉苁蓉属的列当通过HGT从亚洲大蒜芥族或十字花科的一个近缘族中获得了两个相关的核基因（命名为BO转座酶基因），这是II类转座子hAT超家族的一个新类群。侧翼基因的共线性、缺乏经典的边界结构以及低表达水平表明BO转座酶基因在十字花科中不能转座，而它们在埃及列当中高度表达。
