Newly synthesized wheat allohexaploids display progenitor-dependent meiotic stability and aneuploidy but structural genomic additivity
Newly synthesized wheat allohexaploids display progenitor-dependent meiotic stability and aneuploidy but structural genomic additivity
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DOI：
10.1111/j.1469-8137.2010.03186.x
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发表时间：
2010-01-01
期刊：
影响因子：
9.4
通讯作者：
Jahier, Joseph
中科院分区：
文献类型：
--
作者：
Mestiri, Imen;Chague, Veronique;Jahier, Joseph
P>为了了解导致稳定异源多倍体物种的关键机制，我们表征了小麦异源六倍体与结构和遗传变化相关的减数分裂行为。为此，我们分析了通过种间杂交获得的第一代合成异源六倍体，然后在小麦和节节小麦品种（分别为AB和D基因组的供体）的几种基因型之间进行自发染色体加倍。正如对这些Ph1的预期一样（同源配对1）携带基因的异源多倍体，减数分裂中期I的染色体配对基本上发生在同源染色体之间。然而，不同的合成异源六倍体表现出祖细胞依赖性减数分裂不规则性，例如不完全同源配对，导致单价形成并导致下一代的非整倍性。合成异源六倍体的稳定性被证明取决于AB和D基因组祖细胞的基因型，其中在减数分裂和整倍性的规律性方面很少有组合与天然小麦异源六倍体相比。非整倍性是在这些合成异源六倍体中观察到的唯一结构变化，因为在使用从表达序列标签（EST）以及简单序列重复（SSR）和转座元件序列开发的分子标记分析整倍体植物时，没有观察到明显的DNA序列消除或重排。
P>To understand key mechanisms leading to stabilized allopolyploid species, we characterized the meiotic behaviour of wheat allohexaploids in relation to structural and genetic changes.For that purpose, we analysed first generations of synthetic allohexaploids obtained through interspecific hybridization, followed by spontaneous chromosome doubling, between several genotypes of Triticum turgidum and Aegilops tauschii wheat species, donors of AB and D genomes, respectively.As expected for these Ph1 (Pairing homoeologous 1) gene-carrying allopolyploids, chromosome pairing at metaphase I of meiosis essentially occurs between homologous chromosomes. However, the different synthetic allohexaploids exhibited progenitor-dependent meiotic irregularities, such as incomplete homologous pairing, resulting in univalent formation and leading to aneuploidy in the subsequent generation.Stability of the synthetic allohexaploids was shown to depend on the considered genotypes of both AB and D genome progenitors, where few combinations compare to the natural wheat allohexaploid in terms of regularity of meiosis and euploidy. Aneuploidy represents the only structural change observed in these synthetic allohexaploids, as no apparent DNA sequence elimination or rearrangement was observed when analysing euploid plants with molecular markers, developed from expressed sequence tags (ESTs) as well as simple sequence repeat (SSR) and transposable element sequences.