Abstract：
The initial free expansion of the embryo within a seed is at some point inhibited by its contact with the testa, resulting in its formation of folds and borders. Although less obvious, mechanical forces appear to trigger and accelerate seed maturation. However, the mechanistic basis for this effect remains unclear. Manipulation of the mechanical constraints affecting either the in vivo or in vitro growth of oilseed rape embryos was combined with analytical approaches, including magnetic resonance imaging and computer graphic reconstruction, immunolabelling, flow cytometry, transcriptomic, proteomic, lipidomic and metabolomic profiling. Our data implied that, in vivo, the imposition of mechanical restraints impeded the expansion of testa and endosperm, resulting in the embryo\'s deformation. An acceleration in embryonic development was implied by the cessation of cell proliferation and the stimulation of lipid and protein storage, characteristic of embryo maturation. The underlying molecular signature included elements of cell cycle control, reactive oxygen species metabolism and transcriptional reprogramming, along with allosteric control of glycolytic flux. Constricting the space allowed for the expansion of in vitro grown embryos induced a similar response. The conclusion is that the imposition of mechanical constraints over the growth of the developing oilseed rape embryo provides an important trigger for its maturation.
摘要：
胚胎在种子中的初始自由扩张在某些时候被其与睾丸的接触所抑制，导致其褶皱和边界的形成。虽然不太明显，机械力似乎触发和加速种子成熟。然而,这种效应的机理基础尚不清楚.将影响油籽油菜胚体内或体外生长的机械约束的操纵与分析方法相结合，包括磁共振成像和计算机图形重建，免疫标记，流式细胞术,转录组，蛋白质组学，脂质组学和代谢组学分析。我们的数据暗示，在体内，施加机械限制阻碍了睾丸和胚乳的扩张，导致胚胎变形。细胞增殖的停止以及脂质和蛋白质储存的刺激暗示了胚胎发育的加速，胚胎成熟的特征。潜在的分子特征包括细胞周期控制元件，活性氧代谢和转录重编程，以及糖酵解通量的变构控制。缩小空间以扩大体外生长的胚胎会引起类似的反应。结论是，对发育中的油菜油菜胚的生长施加机械约束为其成熟提供了重要的触发因素。
