谷氨酸脱氢酶与谷氨酰胺合成酶对高山被孢霉脂肪酸合成的影响与调控机制研究

Mortierella alpina, that can accumulate fatty acids up to 50% of its dry weight, is a food grade polyunsaturated fatty acids industrial production fungi. But, the fatty acid accumulation mechanism of M. alpina is still not well understood. In recent studies, glutamate metabolic pathways were surprisingly found to play important roles during fatty acid synthesis. In the present project, from the perspective of the effect of glutamate dehydrogenase (GDH) and glutamine synthetase (GS) on lipid synthesis, the relations between fatty acid synthesis and GDH and GS will be systematic analyzed using a combination of methods based on metabolic network simulationand transcription analysis. The glutamate pathway will be reconstructed via overexpression and RNAi approaches on the key genes to affect the fatty acid synthesis of M. alpina. The transcript, metabolic and fatty acid variation of recombinant strains will be analyzed to clarify the regulation mechanisms of GDH and GS on fatty acids synthesis in M. alpina. The results will helpful for expanding the basic theory of fatty acid synthesis in oleaginous microbes, and have important guiding significance for the nutrition and health related studies and genetic engineering of M. alpina.

高山被孢霉是一种可以积累脂肪酸达到自身干重50%的食品级多不饱和脂肪酸工业生产真菌。但是，对于高山被孢霉实现脂肪酸积累的机制仍然缺乏足够的了解。在近年来的研究意外的发现，谷氨酸代谢途径有可能在产油微生物的脂肪酸合成过程中发挥着重要的作用。本项目以高山被孢霉为研究对象，从谷氨酸脱氢酶（GDH）和谷氨酰胺合成酶（GS）与脂肪酸合成的关系角度出发，通过代谢网络模型模拟分析与转录分析相结合的方法系统的确定GDH和GS对脂肪酸合成的影响。使用过表达和基因沉默的方法，通过改造谷氨酸代谢通路来影响高山被孢霉的脂肪酸合成，进而分析重组菌株的转录、代谢和脂肪酸变化规律，明确GDH和GS对脂肪酸合成的调控机制。本研究将从谷氨酸代谢这个新视点为揭示产油微生物脂肪酸合成的机制奠定基础，为脂肪酸代谢相关的营养与健康研究和高山被孢霉的基因工程改造提供新的思路。