A Promising Study Of Isoflavone Accumulation In Astragalus Membranaceus Adventitious Roots

Isoflavones in Huangqi have multiple pharmacological properties.Adventitious roots culture has become a feasible way to obtain secondary metabolites.However,isoflavones in A.membranaceus adventitious roots（AMARs）are still lower and the accumulation mechanism of isoflavones in AMARs is still not known.To dissect mechanism of isoflavone accumulation in AMARs and provide a theoretical basis for large-scale production of isoflavones,present study explored the effects of medium strength,culture time,hydrogen peroxide（H₂O₂）and precursor phenylalanine（Phe）on isoflavone accumulation and key gene expressions of isoflavone pathway using the AMARs as experimental materials.The results showed that the isoflavone yield of AMARs was the highest on B5 medium strength for 35 days of culture,the content of calycosin-7-O-β-D-glucoside（CG）of AMARs was rapidly increased at 200 μM H₂O₂ for 12 hours,and the maximum CG content(269.9 μg·g^-1)was achieved at 200 μM H₂O₂ and 300 μM Phe for 5 days,reaching the standard of Pharmacopoeia of the People’s Republic of China（2015）.H₂O₂ treatment significantly increased the content of salicylic acid（SA）indicated that SA may participate in CG accumulation as a downstream signal of H₂O₂.Expressions of chalcone reductase and isoflavone synthase genes were consistent with the CG accumulation by treatments of H₂O₂ alone and H₂O₂ plus Phe.