植物如何将其对能量的需求与燃料生长所需的减少功率联系起来尚不清楚。激活的葡萄糖形式和NADPH是产生途径的关键前体,分别,能量和减少合成代谢的力量。此外,它们是真菌以及植物中海藻糖-磷酸合酶(TPS1)的底物或变构调节剂。TPS1合成信号代谢产物海藻糖-6-磷酸(T6P)和,因此,有可能将减少功率与能量代谢与燃料生长联系起来。讨论了一种工作模型,其中对SnRK1的海藻糖-6-磷酸(T6P)抑制是年轻且代谢活跃的异养植物组织中生长调节回路的一部分。SnRK1是Snf1相关激酶1和动物AMP依赖性蛋白激酶的植物同源物,中央能量计。响应于细胞中高蔗糖水平的T6P积累抑制SnRK1活性,从而促进合成代谢过程和生长。当T6P水平下降由于低葡萄糖-6-磷酸,尿苷-二磷酸葡萄糖,和改变NADPH或由于受限的TPS1活性,活性SnRK1促进响应能量和碳剥夺所需的分解代谢过程。该模型解释了为什么发现过少或过多的T6P具有生长抑制作用:没有TPS1的拟南芥胚和幼苗生长受阻,而海藻糖培养基上积累T6P的拟南芥幼苗生长受阻。最后,关于T6P代谢的可能作用获得的洞察力,已知改变植物的发育和环境反应,正在讨论。
How plants relate their requirements for energy with the reducing power necessary to fuel growth is not understood. The activated glucose forms and NADPH are key precursors in pathways yielding, respectively, energy and reducing power for anabolic metabolism. Moreover, they are substrates or allosteric regulators of trehalose-phosphate synthase (TPS1) in fungi and probably also in plants. TPS1 synthesizes the signalling metabolite trehalose-6-phosphate (T6P) and, therefore, has the potential to relate reducing power with energy metabolism to fuel growth. A working model is discussed where trehalose-6-phosphate (T6P) inhibition of SnRK1 is part of a growth-regulating loop in young and metabolically active heterotrophic plant tissues. SnRK1 is the Snf1 Related Kinase 1 and the plant homologue of the AMP-dependent protein kinase of animals, a central energy gauge. T6P accumulation in response to high sucrose levels in a cell inhibits SnRK1 activity, thus promoting anabolic processes and growth. When T6P levels drop due to low glucose-6-phosphate, uridine-diphosphoglucose, and altered NADPH or due to restricted TPS1 activity, active SnRK1 promotes catabolic processes required to respond to energy and carbon deprivation. The model explains why too little or too much T6P has been found to be growth inhibitory: Arabidopsis thaliana embryos and seedlings without TPS1 are growth arrested and Arabidopsis seedlings accumulating T6P on a trehalose medium are growth arrested. Finally, the insight gained with respect to the possible role of T6P metabolism, where it is known to alter developmental and environmental responses of plants, is discussed.