Molecular mechanism of elicitor-induced tanshinone accumulation in Salvia miltiorrhiza hairy root cultures

To develop an optimal bioprocess for the production of tanshinone which is mainly used for the treatment of cardiocerebral vascular disease, the tanshinone biosynthetic pathway regulation must be better understood. In this paper, expression of tanshinone biosynthetic pathway related genes as well as tanshinone accumulation in Salvia miltiorrhiza hairy root cultures were investigated, in response to biotic and abiotic elicitors, respectively. Our results showed tanshinone accumulation in S. miltiorrhiza hairy roots was highly regulated by the coordination of the expression of several genes involved in tanshinone biosynthesis pathway. Our results showed a positive correlation between gene expression and tanshinone accumulation, suggesting that tanshinone accumulation may be the result of the coexpression up-regulation of several genes involved in tanshinone biosynthesis under the treatment of various elicitors. Meantime, SmHMGR, SmDXS2, SmFPPS, SmGGPPS and SmCPS were identified as the potential key enzymes in the pathway for targeted metabolic engineering to increase accumulation of tanshinone in S. miltiorrhiza hairy roots. This is the first report integrating comprehensively the transcript and metabolite biosynthesis of tanshinone in S. miltiorrhiza hairy roots.