Seed Architecture Shapes Embryo Metabolism in Oilseed Rape
Seed Architecture Shapes Embryo Metabolism in Oilseed Rape
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DOI：
10.1105/tpc.113.111740
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发表时间：
2013-05-01
期刊：
影响因子：
11.6
通讯作者：
Rolletschek, Hardy
中科院分区：
文献类型：
--
作者：
Borisjuk, Ljudmilla;Neuberger, Thomas;Rolletschek, Hardy
植物胚被限制在种子内发育，必须调整其形状和大小以适应可用的空间。在这里，我们展示了这种调整如何塑造光合胚胎的代谢。非侵入性的基于核磁共振成像的发展中的油菜（甘蓝型油菜）种子说明，胚弯曲后，脂质浓度梯度成为建立。这与光合电子传递速率和贮藏产物的积累有关。实验诱导的胚胎形态和/或光供应的变化改变了这些梯度，并伴随着蛋白质组和代谢组的改变。组织特异性代谢模型预测，外子叶和下胚轴/胚根产生大量的质体还原剂/ATP通过光合作用，而内子叶，被包围的外子叶，被迫生长基本上是异养。在田间相关的突出条件下，核酮糖-1，5-二磷酸羧化酶/加氧酶旁路对种子贮藏代谢的主要贡献仅针对外子叶和下胚轴/胚根。在体外与在植物生长的胚胎之间的差异表明，胚胎的代谢异质性是不能观察到的体外方法。我们的结论是，在体内代谢通量的局部调节和连接到种子结构，驱动胚胎有效地利用可用的光和空间。
Constrained to develop within the seed, the plant embryo must adapt its shape and size to fit the space available. Here, we demonstrate how this adjustment shapes metabolism of photosynthetic embryo. Noninvasive NMR-based imaging of the developing oilseed rape (Brassica napus) seed illustrates that, following embryo bending, gradients in lipid concentration became established. These were correlated with the local photosynthetic electron transport rate and the accumulation of storage products. Experimentally induced changes in embryo morphology and/or light supply altered these gradients and were accompanied by alterations in both proteome and metabolome. Tissue-specific metabolic models predicted that the outer cotyledon and hypocotyl/radicle generate the bulk of plastidic reductant/ATP via photosynthesis, while the inner cotyledon, being enclosed by the outer cotyledon, is forced to grow essentially heterotrophically. Under field-relevant highlight conditions, major contribution of the ribulose-1,5-bisphosphate carboxylase/oxygenase-bypass to seed storage metabolism is predicted for the outer cotyledon and the hypocotyl/radicle only. Differences between in vitro-versus in planta-grown embryos suggest that metabolic heterogeneity of embryo is not observable by in vitro approaches. We conclude that in vivo metabolic fluxes are locally regulated and connected to seed architecture, driving the embryo toward an efficient use of available light and space.