Defining the role of the ABI4 transcription factor in the sugar regulated control of storage oil breakdown in Arabidopsis

所有生物体在细胞中都保持一定水平的可溶性碳水化合物，并利用这些碳水化合物来支持呼吸和生长。为了达到这个碳水化合物浓度被感知，适当的代谢途径被激活和抑制，以增加或减少碳的流动，通过必要的过程。这个过程被称为代谢反馈。不能调节碳水化合物水平会导致发育缓慢甚至疾病，比如糖尿病。在植物中，这个过程调节了储存储备的积累，这些储备构成了我们吃的大部分食物。植物感知细胞内可溶性糖的浓度，并在过量时上调储备沉积（如淀粉合成），在消耗时上调储备分解（淀粉、脂肪酸或蛋白质中的氨基酸）。在幼苗发育的早期，植物依靠分解储存的脂肪酸作为能量来源，因为它们还没有发展出通过光合作用从大气中固定碳的装置。脂肪酸分解代谢可以通过提供糖来抑制，这使得它成为研究植物代谢反馈网络的一个很好的模型系统。我们最近发现ABI4基因抑制模式植物拟南芥的脂质分解。ABI4编码一种转录因子，这意味着它的功能是控制其他基因的活性。许多已知的ABI4靶基因受代谢状态的调控，提示其在代谢反馈控制中起作用。ABI4还在植物激素ABA的应答中起作用，众所周知，ABA在植物糖应答中起作用。这项工作旨在了解代谢反馈控制如何在植物中起作用，ABI4的作用如何被调节，以及ABI4如何在糖水平的反应中关闭脂肪酸分解代谢。

All living organisms maintain constant levels of soluble carbohydrates in their cells, and use these to support respiration and growth. In order to achieve this carbohydrate concentration is sensed and appropriate metabolic pathways are activated and repressed to increase or decrease the flow of carbon through essential processes as required. This process is known as metabolic feedback. Failure to regulate carbohydrate levels can lead to slow development or even disease, such as in the case of diabetes. In plants this process regulates the accumulation of stored reserves, which form much of the food we eat. Plants sense the intracellular concentration of soluble sugars and in times of excess up-regulate reserve deposition, such as starch synthesis, and in times of depletion up-regulate reserve breakdown, either from starch, fatty acids or amino acids from proteins. During early seedling development plants are dependent on the breakdown of stored fatty acids for their energy source, as they have not yet developed the apparatus for fixing carbon from the atmosphere through photosynthesis. Fatty acid catabolism can be inhibited by the provision of sugars, making this an excellent model system to study metabolic feedback networks in plants. We have recently shown that the ABI4 gene represses lipid breakdown in the model plant Arabidopsis. ABI4 encodes a transcription factor, meaning that it's function is to control the activity of other genes. Many of the known target genes of ABI4 are subject to regulation by metabolic status, suggesting a role in metabolic feedback control. ABI4 also functions in the response to the plant hormone ABA which is well known to play a role in plant sugar responses. This work aims to understand how metabolic feedback control works in plants, how ABI4 action is regulated and how ABI4 can turn off fatty acid catabolism in response to sugar levels.