Trehalose 6-phosphate coordinates organic and amino acid metabolism with carbon availability
Trehalose 6-phosphate coordinates organic and amino acid metabolism with carbon availability
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DOI：
10.1111/tpj.13114
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发表时间：
2016-02-01
期刊：
影响因子：
7.2
通讯作者：
Lunn, John E.
中科院分区：
文献类型：
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作者：
Figueroa, Carlos M.;Feil, Regina;Lunn, John E.
海藻糖6-磷酸（Tre 6P）是植物体内一种重要的信号代谢产物，它将植物的生长发育与碳代谢联系起来。蔗糖-Tre 6P关系模型假设Tre 6P充当蔗糖水平的信号和负反馈调节剂。为了测试这个模型，短期的代谢反应，诱导增加Tre 6P水平进行了研究，在拟南芥植物表达大肠杆菌Tre 6P合酶基因（otsA）的控制下，乙醇诱导型启动子。增加的Tre 6P水平导致蔗糖含量的瞬时降低，硝酸还原酶和磷酸烯醇丙酮酸羧化酶的翻译后激活，以及有机酸和氨基酸水平的增加。放射性同位素（（CO2）-C-14）和稳定同位素（（CO2）-C-13）标记实验表明，在植物的光合同化物输出率与升高的Tre 6P没有变化，但增加标记的有机酸。我们的结论是，高Tre 6 P水平通过刺激硝酸盐同化和有机酸的回补合成来降低蔗糖水平，从而将光同化物从蔗糖中转移出来，以产生碳骨架和固定氮用于氨基酸合成。这些结果与蔗糖-Tre 6P关系模型一致，并暗示Tre 6P在植物中协调碳和氮代谢。
Trehalose 6-phosphate (Tre6P) is an essential signal metabolite in plants, linking growth and development to carbon metabolism. The sucrose-Tre6P nexus model postulates that Tre6P acts as both a signal and negative feedback regulator of sucrose levels. To test this model, short-term metabolic responses to induced increases in Tre6P levels were investigated in Arabidopsis thaliana plants expressing the Escherichia coli Tre6P synthase gene (otsA) under the control of an ethanol-inducible promoter. Increased Tre6P levels led to a transient decrease in sucrose content, post-translational activation of nitrate reductase and phosphoenolpyruvate carboxylase, and increased levels of organic and amino acids. Radio-isotope ((CO2)-C-14) and stable isotope ((CO2)-C-13) labelling experiments showed no change in the rates of photoassimilate export in plants with elevated Tre6P, but increased labelling of organic acids. We conclude that high Tre6P levels decrease sucrose levels by stimulating nitrate assimilation and anaplerotic synthesis of organic acids, thereby diverting photoassimilates away from sucrose to generate carbon skeletons and fixed nitrogen for amino acid synthesis. These results are consistent with the sucrose-Tre6P nexus model, and implicate Tre6P in coordinating carbon and nitrogen metabolism in plants.