Drought stress stimulates terpenoid backbone and triterpenoid biosynthesis pathway to promote the synthesis of saikosaponin in Bupleurum chinense DC. roots

Bupleurum chinense, the roots are rich in saikosaponins, is an important medicinal plant in China. However, there is little information on how this plant transcribes and synthesizes saikosaponins under drought stress. We carried out a study on how drought stress stimulated the transcriptional changes of B. chinense and finally synthesized saikosaponins. The accumulation of saikosaponin showed obvious short-term stress effect under the stimulation of drought stress, especially from the RD_1 stage to the RD_2 stage. In the above short-term process, drought stress stimulates terpenoid backbone and triterpenoid biosynthesis pathway to promote the synthesis of saikosaponin in B. chinense roots. At the same time, it stimulated the rapid increase of the contents of three plant hormones. Moreover, we also found that one P450 and two UGTs may be involved in the synthesis of saikosaponins, which is of great significance for the further development of the molecular mechanism of saikosaponins synthesis. More importantly, our research results also have a good reference significance for the cultivation of B. chinense. This study provides a practical means to ensure the "orderly, safe and effective" quality of B. chinense, and has scientific value in promoting the modernization of China Agriculture Research System (CARS).