ABSTRACT
<p><b>OBJECTIVE</b>To investigate the synergistic effects of a biotic elicitor yeast extract and different abiotic elicitors (Ag+, Co2+ and alpha-amino isobutyric acid) on the production of tanshinones in Salvia miltiorrhiza hairy root.</p><p><b>METHOD</b>Different elicitors and their combinations were added to S. miltiorrhiza hairy root culture and the contents of three major tanshinones (crypotanshinone, tanshinone I and tanshinone II A) were analyzed by HPLC.</p><p><b>RESULT</b>The combinations of yeast extract with different abiotic elicitors had notable synergistic effects on the tanshinone I and tanshinone II A production but not on crypotanshinone. The combination of yeast extract and Ag+ (300 micromol x L(-1)) yielded the highest tanshinone I content, which was nearly 14-fold of the control, and the synergistic elicitation coefficient was 3.0. The combination of yeast extract and Co2+ (100 micromol L(-1)) led to the highest tanshinone IIA content, which was about 14.5-fold of the control, and the synergistic elicitation coefficient was 2.1. Only yeast extract combined with alpha-amino isobutyric acid (200 micromol x L(-1)) increased the crypotanshinone content more effectively than single elicitors. The highest crypotanshinone content was 1.28 mg x g(-1), about 30-fold of the control with a synergistic elicitation coefficient of 1.3.</p><p><b>CONCLUSION</b>The elicitation by the combination of a biotic elicitor and an abiotic elicitor can generate a synergistic effect, which is more effective than single elicitors to promote secondary metabolite production in plant tissue cultures.</p>