Novel Benzothiazole Derivatives as Potential Anti-Quorum Sensing Agents for Managing Plant Bacterial Diseases: Synthesis, Antibacterial Activity Assessment, and SAR Study
Pan-Long Chu, Yu‐Mei Feng, Zhou‐Qing Long, Wan‐Lin Xiao, Jin Ji, Xiang Zhou, Pu‐Ying Qi, Taihong Zhang, Heng Zhang, Liwei Liu, Song Yang
Abstract
As quorum sensing (QS) regulates bacterial pathogenicity, antiquorum sensing agents have powerful application potential for controlling bacterial infections and overcoming pesticide/drug resistance. Identifying anti-QS agents thus represents a promising approach in agrochemical development. In this study, the anti-QS potency of 53 newly prepared benzothiazole derivatives containing an isopropanolamine moiety was analyzed, and structure–activity relationships were examined. Compound D 3 exhibited the strongest antibacterial activity, with an in vitro EC 50 of 1.54 μg mL –1 against Xanthomonas oryzae pv oryzae ( Xoo ). Compound D 3 suppressed QS-regulated virulence factors (e.g., biofilm, extracellular polysaccharides, extracellular enzymes, and flagella) to inhibit bacterial infection. In vivo anti- Xoo assays indicated good control efficiency (curative activity, 47.8%; protective activity, 48.7%) at 200 μg mL –1 . Greater control efficiency was achieved with addition of 0.1% organic silicone or orange peel essential oil. The remarkable anti-QS potency of these benzothiazole derivatives could facilitate further novel bactericidal compound development.