丹参异戊烯焦磷酸异构酶是由两条同源基因组成的小基因家族，是萜类化合物下游代谢途径的总开关，在萜类物质合成过程中具有十分重要的限速作用，但目前对这两条基因各自的功能研究还没有定论。我们前期工作发现在丹参毛状根中干扰SmIPI基因的表达，将导致毛状根大量死亡，且存活株系中二萜丹参酮类物质含量几乎检测不到，由此预测SmIPI基因或对丹参正常生长和次生代谢产物积累均具有重要意义，但研究缺乏进一步的结果验证。本项目将以丹参植株为载体，构建目的基因的 RNA干扰载体转化丹参植株，检测转基因材料初生和次生代谢物水平，并借助13C稳定同位素标记法分析SmIPI在MEP和MVA途径中的作用方式，探索SmIPI基因家族成员各自的生理和代谢功能问题，对阐明萜类物质合成途径，揭示SmIPI基因家族功能规律具有重要意义，同时也为MVA和MEP途径代谢调控提供新的靶点。

Isopentenyl Diphosphate Isomerase of Savia miltiorrhiza is of a small gene family which is composed of two homologous genes. It is the master switch of downstream pathways of terpenoids and it plays an important role in the speed-limit of terpenoid synthesis. However, it has not been determined how each of the two genes work. In our previous work, RNA interference of SmIPI in hairy roots of S. miltiorrhiza led to a wide range of death, content of tanshinones in survival lines could not be detected. It can be infered that SmIPI takes important effects on both normal growth and the terpenoids accumulation, but it needs the further results to verify. In this project, RNA interference of SmIPI1 and SmIPI2 in plantlets of S.miltiorrhiza will be conducted at the same term. Content of primary and secondary metabolites will be detected in transgenic plantlets, furthermore, 13C stable isotope labeling method will be used to analize the action mode of SmIPI in the MEP and MVA pathways. This project will be benefit to explore the physiological and metabolic functions of SmIPI gene family, besides, it is helpful to elucidate the terpenoid biosynthesis pathway and has vital significance for revealing the activity rules of the SmIPI gene family. In the meanwhile, it provides new targets for MEP and MVA metabolic regulations.