Nitric oxide interacts with reactive oxygen species to regulate oligosaccharide-induced artemisinin biosynthesis in Artemisia annua hairy roots

This work was to characterize the generation of nitric oxide (NO) and reactive oxygen species (ROS) in Artemisia annua roots induced by an oligosaccharide elicitor (OE) from Fusarium oxysporum mycelium and their relationship with artemisinin production. In the hairy root cultures, the OE at 0.3 mg total sugar/ml evoked a rapid production of nitric oxide synthase (NOS)-dependent NO and hydrogen peroxide (H 2O 2). The NO donor, sodium nitroprusside (SNP) potentiated OE-induced H 2O 2 production. The OE-induced NOS activity was suppressed by NADPH oxidase inhibitor diphenylene iodonium (DPI) and H 2O 2 scavenger catalase (CAT), while the induced NADPH oxidase activity was decreased by the NOS inhibitor and NO scavenger. Moreover, the OE-induced NO and ROS were involved in stimulating the artemisinin accumulation in the hairy roots. These results suggest that NO and ROS could play a role in the elicitor-induced responses and secondary metabolism activities in A. annua.