Iron oxide nanoparticle (Fe3O4-NP) elicitation of Artemisia annua L. in vitro toward enhancing artemisinin production through overexpression of key genes of terpenoids biosynthesis pathway and induction of oxidative stress

Abstract An important phytochemical compound with bioactive properties is artemisinin, which is extracted from Artemisia annua L.. Frontline malaria treatments are artemisinin-based combination therapies (ACTs). The expression of key genes in the biosynthesis pathway of artemisinin can be regulated through metabolic engineering. In this study, we evaluated changes in the mRNA levels of the AaWRKY1 , AaMYB2 , HMGR , and CYP71A1 genes following the application of iron oxide nanoparticles (Fe 3 O 4 -NPs) after 0, 4, 8, 24, 48, and 96 h of spraying at concentrations of 0, 50, 100, and 200 mg L − 1 on the leaves of 6-week-old A. annua plants. The total protein contents and the activity of the CAT, POX, SOD, and PAL enzymes were increased by Fe 3 O 4 -NP, which triggered an enzymatic defense system associated with reactive oxygen species (ROS). This ROS-related defense mechanism was activated by Fe 3 O 4 -NPs, which significantly stimulated the expression of those target key genes and raised the artemisinin levels in A. annua . The artemisinin content increased after 96 h by 98.5%, 76.3%, and 77% in plants treated with the three Fe 3 O 4 -NP concentrations, respectively compared to the control. These findings can help the commercial production of this important medicinal compound both in vivo and in vitro .