原萜烷型四环三萜类化合物是泽泻属等少数植物类群中所特有的活性成分，具有抗癌、抗高血脂、抗HIV等生理活性。由于该类资源性成分自然分布窄，含量低，不能满足利用需求。课题组已获得该类化合物生物合成关键酶AoPSS1和AoPSS2等基因及相关候选转录因子，本项目在前期工作基础上提出：原萜烷型三萜类化合物的生物合成取决于关键酶的催化效率，其表达水平受转录因子及诱导子等调控，关键前体原萜烷型三萜骨架原甾醇的形成是其生物合成的核心，而合成生物学研究是解决该类资源性成分稀缺的有效途径。拟开展研究工作：(1)泽泻原萜烷型三萜生物合成相关候选转录因子的调控功能研究；(2)诱导子对该类化合物生物合成诱导机制研究；(3)构建高效异源表达体系生物合成该类化合物关键前体原甾醇。以阐明泽泻原萜烷型三萜生物合成分子调控机制，获得该类化合物关键前体，为改善泽泻品质及解决该类资源性成分稀缺问题奠定基础。

Protostane triterpenes, which are specific active components in a few plants like Alisma orientale (Sam.) Juz., display bioactivities including anti-cancer, anti-hyperlipidemia and anti-HIV. However, this type of compounds cannot meet the demands for its narrowly natural distribution and low contents. Based on our previous research that we have already cloned several key enzyme genes such as AoPSS1and AoPSS2, and candidate transcription factors, this project propose that the key enzymes’ catalytic effect affect the biosynthesis of protostane triterpenes in A. orientale (Sam.) Juz. as well as their expression levels were regulated by transcription factors and elicitors; Furthermore, the construction of the carbon skeleton protosterol in protostane triterpenes is considered as the key step in its biosynthesis pathway; while Synthetic Biology concerned about how to solve the resource scarcity of these active components effectively. The objects of this research subject including: (1) Clarify the regulatory mechanism of the transcription factors which involved in biosynthesis pathway of protostane triterpenes in A. orientale (Sam.) Juz. (2) Study the biosynthesis mechanism of protostane triterpenes induced by elicitors in A. orientale (Sam.) Juz. (3) Build the heterologous expression system to synthesize the key precursor protosterol in A. orientale (Sam.) Juz. This research subject will not only illustrate the biosynthesis regulatory mechanism but also obtain the key precursor of protostane triterpenes in A. orientale (Sam.) Juz, thus provide a foundation to improve the quality of A. orientale (Sam.) Juz. and a clue to solve the resource scarcity.