A re-evaluation of the homoploid hybrid origin of Aegilops tauschii, the donor of the wheat D-subgenome
A re-evaluation of the homoploid hybrid origin of Aegilops tauschii, the donor of the wheat D-subgenome
复制标题
DOI：
10.1111/nph.13294
复制
发表时间：
2015-10-01
期刊：
影响因子：
9.4
通讯作者：
Wendel, Jonathan F.
中科院分区：
文献类型：
--
作者：
Li, Lin-Feng;Liu, Bao;Wendel, Jonathan F.
杂交是促进植物多样化的突出进化力量，无论是否有随后的基因组加倍（Abbott et al.，2013; Soltis等人，2014; Yakimowski & Rieseberg，2014）。山羊草-小麦复合体是研究自然杂交和异源多倍体化如何导致物种多样化的理想系统（Matsuoka，2011）。最近，Marcussen et al.（2014）提出了一个诱人的场景，即祖先D谱系起源于大约500万年前（Mya）古代A和B谱系之间的同倍体杂交（A，B和D谱系的定义见图1）。这种起源模式的证据来自于对核基因的染色体组学和群体遗传学分析，但没有考虑到该物种复合体的进化历史和叶绿体拓扑结构。与此同时，在最近一期的《新植物学家》杂志上，Gornicki et al.（2014）报道了基于8个现代A、S和D基因组二倍体物种和4个多倍体小麦物种的25个叶绿体基因组的Triticum-Aegilops复合体的叶绿体同源性，但他们没有解决D基因组的起源。在这里，通过重新分析研究和额外数据使用的关键数据，我们提出了一个更复杂的混合起源的D基因组的A。tauschii
Hybridization is a prominent evolutionary force promoting plant diversification, either with or without subsequent genome doubling (Abbott et al., 2013; Soltis et al., 2014; Yakimowski & Rieseberg, 2014). The Aegilops–Triticum complex is an ideal system to investigate how natural hybridization and allopolyploidization have caused species diversification (Matsuoka, 2011). Recently, Marcussen et al.(2014) proposed the tantalizing scenario that the ancestral D lineage originated via homoploid hybridization between ancient A and B lineages some 5 million years ago (Mya)(the definition of A, B and D lineages shown in Fig. 1). Evidence for this mode of origin was derived from phylogenomic and population genetic analyses of nuclear genes, but without taking into account the evolutionary history and chloroplast topology of this species complex. Meanwhile, in a recent issue of New Phytologist, Gornicki et al.(2014) reported the chloroplast phylogeny of the Triticum–Aegilops complex based on 25 chloroplast genomes of eight modern A, S and D genome diploid species and four polyploid wheat species, but they did not address the origin of the D genome. Here, by re-analyzing critical data used by both studies and additional data, we present evidence for a more complex hybrid origin of the D genome of A. tauschii.