Glutathione and herbicide resistance in plants

Abstract

Pesticide use is inseparable part of food production. The efficacy of modern agriculture is quite dependent on the chemicals used to fight with pests, including weeds, fungi and insects. Herbicides are chemicals which destroy weeds. According to their mode of action herbicides are divided on 24 groups (Herbicide Resistance Action Committee). The balance between toxicity on weeds and resistance of crops defines herbicide selectivity. Herbicide tolerance depends on the plants variety, development phase, climate, mode of action, dose and the way plants were treated with herbicides. Glutathione is one of the major defense substances of plants. It takes part in many detoxifying mechanisms, like active oxygen species reducing, and also regulates cell defense systems. Glutathione has key role in detoxifying of toxic xenobiotics, including herbicides. In some crops the resistance against herbicides is due to its direct detoxification by forming conjugates with glutathione. The process can be catalyzed by the enzyme glutathione S-transferase. After their forming, conjugates can be metabolized and excreted or can be stored in vacuoles and dead tissues. Many herbicides, such as atrazine, paraquat, etc., induce oxidative events in plant cell. Glutathione takes part in detoxifying active oxygen species and this is a way for indirect enhancement of plant resistance against herbicides. In the current review the mode of action of herbicides inducing oxidative stress will be discussed. Examples of plant antioxidant system response against herbicide action will be presented. The role of glutathione in direct and indirect detoxification of herbicides and increase of plants sustainability will be deeply reviewed.