Methyl Jasmonate Induced Artemisinin Accumulation Mechanism Research

Plant secondary metabolites are important raw materials in the field of pharmaceutical, chemical and food industry, and especially, olefinic terpenoids are the main components of plant secondary metabolites. For example, artemisinin, paclitaxel and vinblastine are well-known terpenoids used as drugs, and their carbon skeleton are biosynthesized through the cytoplasm pathway or plastid isoprene metabolism pathways. At present, the plant isoprenoid metabolic pathways have been researched well. By using the technology of genetic engineering to modify plant isoprene metabolic pathway transformation has become a reality. Besides, through genetic engineering technology to improve the production of secondary metabolite has become a hot spot. Due their long and multiple biosynthesis pathways, the metabolites content can not be improved significantly through over-expression of one or two genes.Through the" broaden sources of income and reduce expenditure" strategy to improve secondary metabolites is difficult to achieve the expected experimental result.Recent studies suggested that the plant hormone, hot and cold treatment, and other environmental factors induce can significantly enhance the secondary metabolites. To use plant hormone to induce the biosynthetic pathway of secondary metabolite is one of the important methods to improve their content. The complete theoretical system of inducible mechanisms has not been formed yet. With the ever increasing demand of human demand of these secondary metabolites and fast development of modern biological technology, detailed mechanisms of elicitors are concerned by more and more people.The purpose of this study is to elucidate the regulation and biosynthetic mechanism of artemisinin under methyl jasmonic acid treatment of Artemisia annua, and try to explore the feasible method for artemisinin production. The main research contents and results are summarized as follows. Try to explore the relative expression level of hmgr, dxs, dxr and hdr genes on the upstream pathways, cyp71av1, cpr, aar, aldh1, opr3and red1genes on the downstream pathway, and also the competitive pathway genes of sqs, ecs, cpg and gas with methyl jasmonic acid (MeJA) treated A. annua. As a result, the upstream and dowstream pathways, and the competitive pathway had been up-regulated. The expressions of hmgr and dxr genes on the upstream were promoted obviously, and their expression levels were2.7and5.8higher than control, respectively. And also, cyp71avl and aar genes on the downstream pathway had been increased up to68.5and2times compared with control. Finally, the relative expression level of gas gene on the competitive pathway was3.8times of controlled. According to above MeJA treatment result, the molecular mechanism of artemisinin biosynthesis under plant hormone treatment can be known.