Dysfunction of mitotic cell division at shoot apices triggered severe growth abortion in interspecific hybrids between tetraploid wheat and Aegilops tauschii
Dysfunction of mitotic cell division at shoot apices triggered severe growth abortion in interspecific hybrids between tetraploid wheat and Aegilops tauschii
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DOI：
10.1111/j.1469-8137.2012.04125.x
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发表时间：
2012-06-01
期刊：
影响因子：
9.4
通讯作者：
Takumi, Shigeo
中科院分区：
文献类型：
--
作者：
Hatano, Hitoshi;Mizuno, Nobuyuki;Takumi, Shigeo
普通小麦是一种异源六倍体物种，由栽培四倍体小麦与野生二倍体近缘节节麦杂交产生的种间三倍体杂种内源复制而来。在三倍体小麦杂交种中观察到了杂交不亲和性，包括杂种坏死。在与四倍体小麦杂交的三倍体小麦中，少数与节节麦相似的材料表现出杂种致死，这是由于苗期发育停滞，被称为严重生长败育(SGA)。尽管这种情况可能很严重，但SGA背后的遗传机制尚未被很好地了解。在这里，我们对树冠组织中的基因表达谱进行了比较分析，以表征表现SGA的三倍体杂种的发育停滞。在SGA植物的冠部组织中，许多与防卫相关的基因高度上调，而许多转录因子基因，如KNOTTED1型同源异型盒基因，在顶端分生组织和叶原基中表达下调。SGA植株中细胞周期相关基因的转录积累水平也显著降低，在SGA杂交植株的SAM中没有观察到组蛋白H4表达的细胞。我们的发现表明，SGA在其他类型的异常生长表型中显示出独特的特征，如II型和III型坏死。
Common wheat is an allohexaploid species, derived through endoreduplication of an interspecific triploid hybrid produced from a cross between cultivated tetraploid wheat and the wild diploid relative Aegilops tauschii. Hybrid incompatibilities, including hybrid necrosis, have been observed in triploid wheat hybrids. A limited number of A.similar to tauschii accessions show hybrid lethality in triploid hybrids crossed with tetraploid wheat as a result of developmental arrest at the early seedling stage, which is termed severe growth abortion (SGA). Despite the potential severity of this condition, the genetic mechanisms underlying SGA are not well understood. Here, we conducted comparative analyses of gene expression profiles in crown tissues to characterize developmental arrest in triploid hybrids displaying SGA. A number of defense-related genes were highly up-regulated, whereas many transcription factor genes, such as the KNOTTED1-type homeobox gene, which function in shoot apical meristem (SAM) and leaf primordia, were down-regulated in the crown tissues of SGA plants. Transcript accumulation levels of cell cycle-related genes were also markedly reduced in SGA plants, and no histone H4-expressing cells were observed in the SAM of SGA hybrid plants. Our findings demonstrate that SGA shows unique features among other types of abnormal growth phenotypes, such as type II and III necrosis.