文摘
Tanshinones are health-promoting diterpenoids found in <i>Salvia miltiorrhizai> and have wide applications. Here, <i>SmGGPPSi> (geranylgeranyl diphosphate synthase) and <i>SmDXSIIi> (1-deoxy-d-xylulose-5-phosphate synthase) were introduced into hairy roots of <i>S. miltiorrhizai>. Overexpression of <i>SmGGPPSi> and <i>SmDXSIIi> in hairy roots produces higher levels of tanshinone than control and single-gene transformed lines; tanshinone production in the double-gene transformed line GDII10 reached 12.93 mg/g dry weight, which is the highest tanshinone content that has been achieved through genetic engineering. Furthermore, transgenic hairy root lines showed higher antioxidant and antitumor activities than control lines. In addition, contents of chlorophylls, carotenoids, indoleacetic acid, and gibberellins were significantly elevated in transgenic <i>Arabidopsis thalianai> plants. These results demonstrate a promising method to improve the production of diterpenoids including tanshinone as well as other natural plastid-derived isoprenoids in plants by genetic manipulation of the 2-<i>Ci>-methyl-d-erythritol-4-phosphate (MEP) pathway.