GABA metabolism and ROS induction in lentil (Lens culinarisMedik) plants by synthetic 1,2,3-Thiadiazole compounds

In this study, we investigated the physiological effects of three synthetic 1,2,3-thiadiazole compounds (compound I: 4-[1,2,3]-Thiadiazole-4-yl-phenol, compound II: 1,3-Bis[4-(1,2,3-thiadiazol-4-yl)phenoxy]propane, compound III: 4-(4-{2,3,4,5,6-Penta[4-(1,2,3-thiadiazole-4-yl)phenoxymethyl]benzyloxy}phenyl)-1,2,3-thiadiazole) treatments on plants via the characterization of γ-aminobutyric acid metabolite level, the accumulation of reactive oxygen species (ROS), total protein contents, total carbohydrate contents, fresh weight and dry mass in two lentil (Lens culinaris Medik) cultivars (Jordan 1 and Jordan 2). In response to the three synthetic 1,2,3-thiadiazole compounds (I, II and III) treatments. A significant increase in γ- aminobutyric acid (GABA) and malondialdehyde (MDA) levels and a significant reduction in carbohydrates and protein levels and fresh weight and dry mass were obtained in both lentil cultivars. Jordan 2 cultivar showed the highest GABA and MDA accumulation and significant reduction in the carbohydrate and protein levels under the various thiadiazole compounds treatments. This suggests that GABA molecule may act as a defense mechanism and signaling molecule in carbohydrate metabolism and other physiological systems in lentil. In conclusion, our results revealed that the synthetic 1,2,3-thiadiazole compound ІІ (1,3-Bis[4-(1,2,3-thiadiazol-4-yl)phenoxy]propane) had the strongest physiological inhibitory effect on lentil.