外源诱导姬松茸麦角甾醇的合成

Exogenous Induction of Ergosterol Synthesis in Agaricus blazei

摘要:

为提高姬松茸中麦角甾醇含量，本研究借助液体培养，通过添加外源诱导物提高菌丝中麦角甾醇含量。分别以茉莉酸甲酯（methyl jasmonate，MeJA）和水杨酸（salicylic acid，SA）为外源诱导物，对其添加量、添加时间以及诱导时长进行优化，并通过荧光定量PCR对诱导条件下参与麦角甾醇合成的相关基因表达量进行分析。结果表明，两种诱导物对姬松茸菌丝中麦角甾醇的最佳诱导条件分别为菌丝培养到第8 d加入70.00 μmol/L MeJA和第6 d加入10.00 μmol/L SA，并分别继续培养2 d。优化条件下获得的菌丝中麦角甾醇含量分别为2.35 mg/g和2.43 mg/g，比对照组分别增加了147.37%和155.79%。根据参与麦角甾醇合成的基因表达谱分析推测其诱导机制可能是MeJA和SA直接或间接的启动了麦角甾醇合成上游关键酶基因的表达，并通过参与合成代谢相关酶的相互作用来实现麦角甾醇的合成调控。通过短时间外源诱导培养获得菌丝体中麦角甾醇含量已超过子实体中的，因此可替代子实体开展麦角甾醇的相关研究。

Abstract:

To increase the content of ergosterol in Agaricus blazei, the content of ergosterol in hyphae was increased by adding exogenous inducer under liquid culture condition. In this study, methyl jasmonate (MeJA) and salicylic acid (SA) were used as inducers, the concentration, adding time and duration of induction were optimized, and the transcriptional level of genes involving in ergosterol synthesis of A. blazei was analyzed by quantitative real time PCR. As results, the best induction conditions for ergosterol synthesis of A. blazei were adding 70.00 μmol/L of MeJA and 10.00 μmol/L of SA to the culture broth when the hyphal was culture to 8 d and 6 d, respectively, and continuously culturing 2 days under these conditions. The content of ergosterol in the harvested hyphae was respectively 2.35 mg/g and 2.43 mg/g, which increased by 147.37% and 155.79% than control group. Moreover, based on the gene expression profiles involving the ergosterol synthesis of A. blazei, it can be speculated that the induction mechanism of MeJA and SA on ergosterol may be they directly or indirectly initiate the expression of upstream key enzyme genes involving in the ergosterol synthesis, and the synthesis was regulated by the interaction of anabolic-related enzymes participating in metabolism. As a conclusion, the content of ergosterol in mycelia obtained by short time exogenous induction culture has exceeded that in fruiting body, so the mycelia obtained in this study can replace the fruiting body to research and apply the ergosterol of A. blazei.