Drought stress-induced methyl jasmonate accumulation promotes calycosin-7- O -β- d -glucoside production in Astragalus membranaceus adventitious roots

Calycosin-7- O -β- d -glucoside (CG) is a major isoflavone in Astragalus membranaceus and has multiple pharmacological activities. Astragalus membranaceus adventitious roots (AMARs) are a source of bioactive compounds. In this study, we demonstrated that drought stress stimulated CG production in AMARs, but the CG content of drought-stressed plants was still lower than that of field-grown plants. Furthermore, we found that drought stress stimulated the accumulation of methyl jasmonate (MeJA), which is involved in drought stress-induced CG production in AMARs. Exogenous application of MeJA efficiently elicited CG production in a concentration- and time-dependent manner, and the maximum CG content was observed at 200 µM MeJA for 8 days, which was 2.02-fold higher than that observed in field-grown plants. In addition, l -phenylalanine feeding further improved MeJA-elicited CG production, which was 3.12-fold higher than that in field-grown plants. Thus, MeJA and MeJA plus L-phenylalanine are promising elicitors for the commercial production of CG in AMARs.