茉莉酸甲酯对茯苓三萜生物合成的调控研究

目的 探索茉莉酸甲酯(methyl jasmonate,MeJA)对茯苓三萜生物合成的调控效应及其机制.方法 从MeJA添加量、添加时间角度考察MeJA对茯苓三萜生物合成的调控效应,确定最佳调控策略,在此基础上采用荧光定量PCR(Real time PCR,RT-PCR)技术分析MeJA对茯苓甲羟戊酸途径法尼基焦磷酸合成酶基因(fps)和鲨烯合酶基因(sqs)基因表达水平的影响,揭示其调控机制.结果 MeJA可显著促进茯苓三萜的生物合成,最佳添加策略为发酵4 d添加150μmol/L的MeJA,此时茯苓三萜得率可达20.95 mg/L,为空白组的1.55倍、吐温-80组的1.32倍;RT-PCR结果显示MeJA可使fps、sqs基因表达水平显著上调,分别为吐温-80对照组的1.17倍、788.70倍.结论 MeJA通过显著上调sqs基因表达实现茯苓三萜生物合成的过程强化,为一种有效的促进茯苓三萜合成的外源调控因子.

Study on Regulation of Triterpenoids Biosynthesis in Poria cocos Submerged Fermentation System by Methyl Jasmonate

Objective To explore the regulation effects and its molecular mechanism of methyl jasmonate (MeJA) on triterpenoid biosynthesis in submerged fermentation system of Poria cocos. Methods The effects of addition amount and feeding time of MeJA on Poria cocos triterpenoid biosynthesis were discussed, respectively. Besides, to illustrate regulation mechanism of MeJA, real time PCR (RT-PCR) was employed to analysis the expression level of fps and sqs in mevalonate (MVA) path-way of Poria cocos. Results The optimal regulation strategy was adding 150 μmol/L MeJA on 4th day. Under this condition, the maximum content can reach up to 20.95 mg/L, which was 1.55 times of blank group, 1.32 times of Tween-80 group. RT-PCR results showed that fps and sqs gene expression level both increased significantly, which were 1.17 times, 788.70 times of that in Tween-80 group, respectively. Conclusion MeJA, as an effective exogenous regulatory factor for increasing triter-penoid biosynthesis level of Poria cocos, could efficiently improve triterpenoid biosynthesis level in Poria cocos submerged fer-mentation system.