激活蛋白AP1参与茉莉酸甲酯诱导灵芝酸合成的调控机理

Ganoderic acids (GA) are main pharmacological compounds in Ganoderma lucidum. In the preliminary work, applicants have found that methyl jasmonate (MeJA) can markedly induce GA biosynthesis in G. lucidum. Through transcriptome analysis of G. lucidum under MeJA induction, activator protein AP1 has been screened out. This gene has been up-regulated under MeJA induction. Further biochemical and genetical experiments indicated that AP1 is involved in the process, which is that MeJA induce GA biosynthesis. However, the mechanism of AP1 regulation in this process remains unknown. Based on the prophase work, the author will carry out this project. Firstly, the relationship among AP1, reactive oxygen species and antioxidant enzyme genes will be investigated on the regulation of GA biosynthesis under MeJA induction. Secondly, the regulation effect of AP1 on antioxidant enzyme genes, GA biosynthetic genes and other unknown downstream genes will be studied. Furthermore, the role of those genes, which were regulated by AP1, will be investigated on GA biosynthesis under MeJA induction though over-expression and gene silence technology. These researches will help to further elucidate the mechanism of GA biosynthesis network regulation, and provide theoretical basis for improving content of GA in G. lucidum. At the same time, it will provide reference for studying on other terpenoid compounds biosynthesis.

灵芝酸是灵芝的主要药用成分，其含量的多少决定了灵芝药用价值的高低。申请者前期研究发现茉莉酸甲酯(MeJA)能促进灵芝酸的生物合成。转录谱研究筛选到灵芝激活蛋白AP1基因。生理生化和遗传学实验研究表明，AP1参与了MeJA诱导的灵芝酸生物合成的调控过程，但是其调控机理尚未阐明。本项目拟在前期研究的基础上，研究1）AP1、活性氧和抗氧化酶基因三者之间在调控MeJA诱导灵芝酸生物合成中的关系；2）AP1对抗氧化酶基因、灵芝酸合成关键基因以及其他AP1调控的下游未知基因的调控作用。3）通过基因过表达和沉默技术研究AP1调控的基因在茉莉酸甲酯诱导灵芝酸生物合成中的作用，揭示AP1参与茉莉酸甲酯诱导灵芝酸生物合成的分子调控机制。研究结果将进一步阐明MeJA促进灵芝酸生物合成的分子机制，为进一步提高灵芝酸含量提供理论基础，加深人们对大型担子菌次生代谢调控的了解，为其它重要萜烯类化合物研究提供借鉴。

灵芝酸是灵芝的主要药用成分，其含量的多少决定了灵芝药用价值的高低。前期研究发现茉莉酸甲酯(MeJA)能促进灵芝酸的生物合成，AP1参与了MeJA诱导的灵芝酸生物合成的调控过程。因此。本研究对AP1调控灵芝酸生物合成的机理进行了研究。结果表明，灵芝激活蛋白AP1调控了胞内ROS水平以及抗氧化相关酶的基因(cat1，cat2，sod1，sod2，sod4，apx，gpx)转录水平以及灵芝酸的生物合成。同时，灵芝激活蛋白ap1基因沉默菌株对过氧化氢胁迫更加敏感。进一步的研究表明ap1基因通过影响胞内ROS水平来调控灵芝酸生物合成。筛选了灵芝转录激活蛋白AP1调控的未知下游基因，包括磷脂酶C基因PLC、谷胱甘肽过氧化物酶基因GPX。通过构建PLC基因沉默菌株，表明PLC参与调控了灵芝酸的生物合成。本研究为灵芝酸生物合成与灵芝胞内ROS信号和ROS信号转导途径研究提供重要的研究基础，有助于进一步加深对灵芝酸生物合成分子机制的认识，为生产上提高灵芝酸含量提供理论基础，同时为更深入研究其它重要萜烯类化合物和担子菌其它活性成分的代谢调控提供借。