Transcription Factor Arabidopsis Activating Factor1 Integrates Carbon Starvation Responses with Trehalose Metabolism
Transcription Factor Arabidopsis Activating Factor1 Integrates Carbon Starvation Responses with Trehalose Metabolism
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DOI：
10.1104/pp.15.00917
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发表时间：
2015-09-01
期刊：
影响因子：
7.4
通讯作者：
Mueller-Roeber, Bernd
中科院分区：
文献类型：
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作者：
Garapati, Prashanth;Feil, Regina;Mueller-Roeber, Bernd
植物对低碳供应的反应是通过对转录组和代谢组的大规模重新编程来实现的。我们发现，碳饥饿诱导的NAC(无顶端分生组织/拟南芥转录激活因子/杯状子叶)转录因子(ATAF1)在这一生理过程中起重要作用。我们发现拟南芥中唯一的海藻糖酶编码基因TREHALASE-1是ATAF1的直接下游靶基因。ATAF1的过表达激活了TREHALASE 1的表达，并导致海藻糖-6-磷酸水平降低和糖饥饿代谢产物。根据淀粉生物合成和分解相关基因表达的变化，在ATAF1过表达的植物中，淀粉水平通常降低，而在ATAF1基因敲除植物中，淀粉水平升高。在全球转录组水平上，受ATAF1影响的基因广泛地与能量和碳饥饿反应相关。此外，ATAF1引发的转录反应在很大程度上与在缺乏碳或能量供应的植物中观察到的表达模式重叠。总体而言，我们的数据强调了在由碳饥饿诱导的ATAF1表达和由ATAF1对下游基因调控网络的转录调控触发的细胞碳/能量池耗尽之间存在一个正向作用的前馈环。
Plants respond to low carbon supply by massive reprogramming of the transcriptome and metabolome. We show here that the carbon starvation-induced NAC (for NO APICAL MERISTEM/ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR/CUP-SHAPED COTYLEDON) transcription factor Arabidopsis (Arabidopsis thaliana) Transcription Activation Factor1 (ATAF1) plays an important role in this physiological process. We identified TREHALASE1, the only trehalase-encoding gene in Arabidopsis, as a direct downstream target of ATAF1. Overexpression of ATAF1 activates TREHALASE1 expression and leads to reduced trehalose-6-phosphate levels and a sugar starvation metabolome. In accordance with changes in expression of starch biosynthesis-and breakdown-related genes, starch levels are generally reduced in ATAF1 overexpressors but elevated in ataf1 knockout plants. At the global transcriptome level, genes affected by ATAF1 are broadly associated with energy and carbon starvation responses. Furthermore, transcriptional responses triggered by ATAF1 largely overlap with expression patterns observed in plants starved for carbon or energy supply. Collectively, our data highlight the existence of a positively acting feedforward loop between ATAF1 expression, which is induced by carbon starvation, and the depletion of cellular carbon/energy pools that is triggered by the transcriptional regulation of downstream gene regulatory networks by ATAF1.