Menadione bisulfite (sodium) is used as an agent to induce acute oxidative stress, and to function as a plant-defense activator against several pathogens. In Vitro: Menadione sodium bisulfite (500 μM) treatment and the concomitant ROS increase have an important impact on the photosynthetic activity of the cells. Global and specific antioxidant defences decrease with Menadione sodium bisulfite (500 μM) treatment^[1]. Menadione sodium bisulfite and PABA activate similar defense responses (PR, ROS, and HR). Menadione sodium bisulfite enhances resistance, both locally and systemically, to phoma stem canker disease caused by Leptosphaeria maculans. Menadione sodium bisulfite treatment induces resistance against downy mildew in pearl millet. Menadione sodium bisulfite acts through priming of specific sets of the plant innate-defense repertoire. Menadione sodium bisulfite treatment up-regulates the expression of a gene encoding a GRX480 protein, a member of the glutaredoxin family that regulates protein redox state^[1].