Metabolomics data reveal a crucial role of cytosolic glutamine synthetase 1;1 in coordinating metabolic balance in rice
Metabolomics data reveal a crucial role of cytosolic glutamine synthetase 1;1 in coordinating metabolic balance in rice
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DOI：
10.1111/j.1365-313x.2011.04506.x
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发表时间：
2011-05-01
期刊：
影响因子：
7.2
通讯作者：
Saito, Kazuki
中科院分区：
文献类型：
--
作者：
Kusano, Miyako;Tabuchi, Mayumi;Saito, Kazuki
稻田中生长的水稻植物优先使用铵作为无机氮源。谷氨酰胺合成酶 (GS) 催化铵转化为谷氨酰胺。在水稻编码胞质 GS 的三个基因中，OsGS1;1 对于正常生长和籽粒灌浆至关重要。然而，其可能改变代谢网络背景下氮同化和碳代谢速率的生理功能基础仍不清楚。为了解决这个问题，我们对缺乏 OsGS1;1 的水稻突变体及其背景野生型 (WT) 的代谢物谱进行了定量比较分析。与野生型相比，突变体植物在铵存在下表现出严重的枝条生长迟缓。突变体叶鞘和根中游离铵的过度积累表明了 OsGS1;1 对于两个器官中铵同化的重要性。突变株系的代谢物谱显示：（i）三羧酸循环中糖、氨基酸和代谢物水平不平衡，以及（ii）次生代谢物过度积累，特别是在持续供应铵的根部中。代谢物与代谢物的相关性分析揭示了色胺和根中其他初级代谢物之间存在突变体特异性网络。这些结果证明了 OsGS1;1 在协调以铵作为氮源生长的水稻植物的整体代谢网络方面的关键功能。
Rice plants grown in paddy fields preferentially use ammonium as a source of inorganic nitrogen. Glutamine synthetase (GS) catalyses the conversion of ammonium to glutamine. Of the three genes encoding cytosolic GS in rice, OsGS1;1 is critical for normal growth and grain filling. However, the basis of its physiological function that may alter the rate of nitrogen assimilation and carbon metabolism within the context of metabolic networks remains unclear. To address this issue, we carried out quantitative comparative analyses between the metabolite profiles of a rice mutant lacking OsGS1;1 and its background wild type (WT). The mutant plants exhibited severe retardation of shoot growth in the presence of ammonium compared with the WT. Overaccumulation of free ammonium in the leaf sheath and roots of the mutant indicated the importance of OsGS1;1 for ammonium assimilation in both organs. The metabolite profiles of the mutant line revealed: (i) an imbalance in levels of sugars, amino acids and metabolites in the tricarboxylic acid cycle, and (ii) overaccumulation of secondary metabolites, particularly in the roots under a continuous supply of ammonium. Metabolite-to-metabolite correlation analysis revealed the presence of mutant-specific networks between tryptamine and other primary metabolites in the roots. These results demonstrated a crucial function of OsGS1;1 in coordinating the global metabolic network in rice plants grown using ammonium as the nitrogen source.