Effects of exogenous methyl jasmonate on artemisinin biosynthesis and secondary metabolites in Artemisia annua L.

Artemisin is a sesquiterpene lactone with an endoperoxide bridge first isolated from the aerial parts of Artemisia annua L. (Compositae). It is an important antimalarial component, but as of present remains quite expensive due to its low content in the plant, the only commercial source of the compound. In this study, we found a 49% increase of the artemisinin content in A. annua SP18 on day 8 after treatment with methyl jasmonate (MeJA), together with an 80% increase in artemisinic acid and 28% in dihydroartemisinic acid, the two potential precursors of artemisinin. In addition, the effects of exogenous MeJA on other secondary metabolites were evaluated by metabolite profiling using orthogonal signal correction partial least square discriminant analysis (OSC-PLS). Six sesquiterpenoids and three triterpenoids were selected as marker compounds in OSC-PLS. Their content also changed significantly after MeJA treatment, including a 50% increase in methyl artemisinic acid, a 67% increase in squalene and a 60% increase in peak 51 (an unidentified sesquiterpenoid). These compounds are promising targets for further studies on artemisinin biosynthesis and metabolic engineering.