柚皮素合成关键基因表达水平对目标产物积累水平的量化影响

Quantitative effect of the expression level of key genes in naringenin synthesis on the accumulation level of target products

摘要:

柚皮素是一种天然黄酮类化合物，具有抗炎、抗氧化、抗病毒、预防动脉粥样硬化等多种药理活性，也是其他黄酮类化合物合成的重要前体，具有重要的应用价值。目前，微生物法生产柚皮素等黄酮类化合物由于代谢通路不平衡等原因导致产量较低，在很大程度上限制了其工业应用。文中以一株产柚皮素的酿酒酵母菌株Y-01为研究对象，利用启动子和拷贝数控制柚皮素合成代谢途径关键酶4-香豆酸：CoA连接酶 (4CL)、查尔酮合成酶 (CHS) 和查尔酮异构酶 (CHI) 编码基因的表达水平，考察这些基因的表达水平对目标产物积累水平的量化影响。结果表明，柚皮素产量与4CL或CHI编码基因的表达量之间关联性较低，而与chs基因的表达量存在显著的正相关性。通过调控chs基因的表达水平，获得一株高产柚皮素的酿酒酵母工程菌株Y-04，产量较出发菌株Y-01提高了4.1倍。研究结果表明，CHS是柚皮素合成过程的关键调控靶点，合理调控CHS表达可以显著促进酿酒酵母积累柚皮素。相关结果为采用代谢工程强化微生物合成柚皮素等重要黄酮类化合物提供了重要的理论参考。

Abstract:

Naringenin is a natural flavonoid compound with anti-inflammatory, anti-oxidation, anti-viral, anti-atherosclerosis and other pharmacological activities. It is also an important precursor of other flavonoid synthesis and with great value of application. At present, the production of flavonoids such as naringenin by microbial methods has a low yield due to imbalance of metabolic pathways, which greatly limits its industrial application. In this study, a naringenin-producing strain of Saccharomyces cerevisiae Y-01 was used in the research object. The expression levels of 4-coumaric acid: CoA ligase (4CL), chalcone synthase (CHS) and chalcone isomerase (CHI) were controlled by promoter and copy numbers to investigate the quantitative effect of key enzyme expression level on the accumulation level of target products. The results showed that the correlation between naringenin production and 4CL or CHI expression was not significant while there was a positive correlation with the expression level of CHS. Strain Y-04 with high yield of naringenin was obtained by regulating the expression level of chs gene, and the yield was increased by 4.1-folds compared with the original strain Y-01. This study indicated that CHS is a key regulatory target of naringenin synthesis. Rational regulation of CHS expression can significantly promote the accumulation of naringenin. The related results provide an important theoretical reference for the use of metabolic engineering to strengthen microbial synthesis of important flavonoids such as naringenin.