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• KAR 1 improved the production of Ca2+–CaM, BL, JA and SAB in S. miltiorrhiza hairy roots. • Ca2+ and BL seem to have a parallel relationship and acts as upstream signaling molecule to medicate the production of JA. • Ca2+–CaM, BL mediated the KAR 1 -induced increase of SAB dependent on the generation of JA in S. miltiorrhiza hairy roots. The effects of smoke-derived karrikins (KAR 1) on the contents of endogenous signal molecules including (Ca2+)–calmodulin (CaM), brassinolide (BL) and Jasmonic acid (JA) and secondary metabolite Salvianolic acid B (SAB) in Salvia miltiorrhiza hairy roots have been investigated. The results showed that the burst of Ca2+–CaM, BL and JA were early responses of S. miltiorrhiza responding to KAR 1. Treatments with exogenous CaCl 2 and BL dramatically improved the level of JA, while JA inhibitor salicylhydroxamic acid/n-propylgallate (SHAM/PrGall) did not influence levels of Ca2+ and BL in S. miltiorrhiza hairy roots. Furthermore, pretreatments with the Ca2+ channel blockers LaCl 3 (La3+) and Verapamil (VERA), and CaM antagonists [N-(6-amin-ohexyl)-5-chloro-1-naphthalene sulfonamide hydrochloride] (W 7) and trifluoperazine (TFP) substantially reduced KAR 1 -induced BL accumulation, while the Ca2+ production induced by KAR 1 was reduced by BL inhibitor Brassinazole (BRz). It suggested that Ca2+ and BL seem to have a parallel relationship and act as upstream signaling molecules to medicate the production of JA. The inhibitory effects of VERA, W 7 , BRz and SHAM toward SAB production induced by the KAR 1 could be reversed by exogenous jasmonate methyl (JAMe), while the exogenous CaCl 2 and BL had no similar effects. It proved that Ca2+–CaM, BL mediated the KAR 1 -induced increase of SAB dependent on the generation of JA in S. miltiorrhiza hairy roots. This study help us understand the regulatory mechanism of Ca2+–CaM, BL, JA on KAR 1 -induced accumulation of SAB in S. miltiorrhiza hairy roots. [ABSTRACT FROM AUTHOR]

Although smoke-water (SW) and butenolide (KAR 1) isolated from smoke show stimulating effects on the production of secondary metabolites in medicinal plants, the underlying mechanisms are not well understood. This study was initiated to investigate the signal molecule in the KAR 1 -induced tanshinones biosynthesis in Salvia miltiorrhiza hairy root. KAR 1 treatment resulted in substantial improvement in the accumulation of jasmonic acid (JA), followed by an increase in lipophilic tanshinones production in S. miltiorrhiza hairy root. Treatment of external JA stimulated the biosynthesis of tanshinones without KAR 1 treatment. KAR 1 -stimulated tanshinones biosynthesis was inhibited with the treatment of SHAM and PrGall, which are JA synthesis inhibitors. This study indicated that JA serves as a role in the signal transduction involved in KAR 1 -stimulated tanshinones biosynthesis in the S. miltiorrhiza. • JA serves as a role in the signal transduction involved in KAR 1 -stimulated tanshinones biosynthesis in the S. miltiorrhiza. • KAR 1 could induce the germination of JA and accumulation of tanshinones in S. miltiorrhiza. [ABSTRACT FROM AUTHOR]