Effects of cerous nitrate on growth and tanshinone production in salvia miltiorrhiza hairy roots

Salvia miltiorrhiza, a popular traditional Chinese medicine, is widely used for treatments in cardiotonic disease. Tanshinones are a group of bioactive ingredients in S. miltiorrhiza. In this study, Ce^3＋ was used as an elicitor to enhance tanshinones production in S. miltiorrhiza hairy roots. The results showed that contents of dihydrotanshinone I（DTI） and cryptotanshinone（CT） were significantly enhanced by 50 μmol/L Ce^3＋, and reached to 0.875 mg/g and 0.271 mg/g, respectively. However, tanshinone II A（TIIA） and tanshinone I（TI） contents were significantly decreased to 59% and 62% of the control. Simultaneously, expressions of genes（HMGR, DXR, DXS1, DXS2 and GGPPS） involved in tanshinone biosynthesis were upregulated by Ce^3＋. Responses of DXS1, DXS2 and GGPPS to Ce^3＋ treatments were later than HMGR and DXR. We speculated that branch pathways of DTI and CT biosynthesis were probably different from TIIA and TI. This work will help us understand biosynthetic mechanism of tanshinones in plants.