Dihydroartemisinin Extract from Artemisia hedinii inhibits spore germination of Alternaria alternata involving membrane peroxidation

Abstract Dihydroartemisinin (DHA) extract is expected to be useful as a biological pesticide for fungal disease control. This study preliminarily explored the mechanism for inhibiting spore germination of Alternaria alternate by DHA extract. The results showed that the EC50, EC90, MIC and MFC of DHA extract on the spores of A. alternata were 1.63 mg/mL, 3.14 mg/mL, 4 mg/mL and 8mg/mL, respectively. The cell membrane permeability of spores treated with DHA extract was enhanced and the integrity was decreased. Meanwhile, the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) increased significantly, indicating that membrane peroxidation occurred in the spores. Significant changes in catalase (CAT) activity were observed, which also demonstrated that an oxidation reaction took place within the spores. These results indicated that the DHA extract produced ROS in the spores, which caused membrane peroxidation and destroyed the membrane, thus, inhibited spores germination of A. alternata. The antifungal activity against A. alternata mechanism of DHA could pave the way for the development of control of tobacco brown spot and other fungal diseases.