Hydrogen peroxide-induced ethylene production promotes calycosin-7-O-β-d-glucoside accumulation in Astragalus membranaceus adventitious roots

Calycosin-7-O-β-d-glucoside (CG) is one of the major active compounds in Astragalus membranaceus roots. A. membranaceus adventitious roots (AMARs) are an alternative source for the production of bioactive components. Hydrogen peroxide (H₂O₂) induces CG accumulation in AMARs. However, the mechanisms underlying CG accumulation remains unclear. In this study, we found that H₂O₂ stimulated the production of ethylene, which is involved in the H₂O₂-induced CG accumulation. The exogenous application of ethephon (a donor of ethylene) induced CG production in a concentration- and time-dependent manner, and the maximum CG content was observed at 20 µM ethephon for eight days, which was 17.0-fold higher than that of the control. Moreover, the addition of methyl jasmonate and phenylalanine further improved ethephon-induced CG production, which was 48.0-fold higher than that of untreated AMARs. These results are valuable for increasing CG production in AMARs.