The effect of elicitors on the metabolites in the suspension cells of Salvia miltiorrhiza Bunge was elucidated by comparing and analyzing the metabolites of induced and uninduced suspension cells. The primary metabolites were detected by GC-MS. Twelve types of secondary metabolites, namely, shikimic acid, tanshinol, protocatechuic acid, caffeic acid, p-coumaric acid, rosmarinic acid, salvianolic acid B, salvianolic acid A, dihydrotanshinone, cryptotanshinone, tanshinone I, and tanshinone II A were detected by HPLC. Results indicated a total of 90 primary metabolites in the cells. These metabolites consisted of 49 kinds of sugars and their derivatives, 15 organic acids, 9 amino acids and their derivatives, 9 hydrocarbons, and 8 other substances. OPLS-DA results indicated five differential primary metabolites, namely, gluconic acid, mannopyranose, glucose, inositol, and ketoisovalerate, between the callus and suspension cells. SA significantly induced glucose metabolism in the S. miltiorrhiza suspension cells, and the mean contents of glucose, fructose, and mannose were significantly lower in the induced cells than in the control. However, SA, as a plant inducer, could significantly promote the increase in 10 secondary metabolites, except protocatechuic acid and tanshinone I, in the suspension cells at different times or degrees. The effect of NaCl on the S. miltiorrhiza cell mainly depended on the downstream pathway of glucose metabolism. Fructose and glucose were the decomposition products of sucrose, and glucose was processed through monosaccharide metabolism. Induction by NaCl resulted in significantly lower levels of these primary metabolites in the induced cells than in the control group. However, NaCl could significantly promote 10 secondary metabolites, except tanshinol and protocatechuic acid, at different times or degrees. After elicitation by AgNO3, sucrose and proline were higher in the induced cells than in the control group. However, galactose and fructose were lower in the experimental cells than in the control. This phenomenon may have been caused by the induction of plant stress response by AgNO3. AgNO3 could significantly promote shikimic acid, caffeic acid, p-coumaric acid, rosmarinic acid, salvianolic acid B, salvianolic acid A, dihydrotanshinone, cryptotanshinone, tanshinone I, and tanshinone IIA. This study will provide a reference for future studies on the effects of primary metabolites on the secondary metabolites and the potential relation of these metabolites to plant stress response in S. miltiorrhiza.
Keywords: Cell culture; Elicitor; Metabolite; Salvia miltiorrhiza.