Development of dual-function disulfaneyl oxadiazole bactericides by structurally incorporating β-carboline moieties

Structural derivatization of known leads using the scaffold hopping strategy is a classic approach in pesticide discovery. However, the modificatory universality of lead skeletons profoundly influences the feasibility of this protocol. We herein report development of disulfaneyl oxadiazole bactericides involving β-carboline moieties. Derivative B18 is filtered out to exhibit excellent in vitro antibacterial properties with half-maximal effective concentrations of 0.47 mg/L, 1.72 mg/L, and 5.97 mg/L against Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Xanthomonas citri pv. citri, respectively. The observed values fall short in comparison to the positive controls thiodiazole copper (TC) and allicin (AC). Moreover, in vivo pot studies reveal that B18 demonstrates enhanced curative (49.12 %) and protective (49.41 %) efficacy in comparison to the control groups TC and AC. Investigation regarding the mechanism of action indicates that B18 functions through a dual antibacterial approach. It not only interferes with the metabolic pathways of starch and sucrose in bacteria, and boosts the activity of rice defense enzymes while upregulating the expression of pyruvate kinase in the glycolytic pathway, thereby enhancing the plant resistance to bacterial pests.