Resistance‐driven innovations in the discovery of bactericides: novel triclosan derivatives decorating isopropanolamine moiety as promising anti‐biofilm agents against destructive plant bacterial diseases
Jiaojiao Zhang, Yu‐Mei Feng, Jun‐Rong Zhang, Wan‐Lin Xiao, Shuai‐Shuai Liu, Xiang Zhou, Heng Zhang, Peiyi Wang, Liwei Liu, Song Yang
Abstract
Abstract BACKGROUND Controlling bacterial infections in plants is a major challenge owing to the appearance of resistant strains. As a physical barrier, the bacterial biofilm helps bacterial infections acquire drug resistance by enabling bacteria to accommodate complex and volatile environmental conditions and avoid bactericidal effects. Thus, developing new antibacterial agents with antibiofilm potency is imperative. RESULTS A series of simple triclosan derivatives containing isopropanolamine moiety were elaborately designed and assessed for their antibacterial behavior. Bioassay results showed that some title compounds had excellent bioactivity against three destructive bacteria Xanthomonas oryzae pv. oryzae ( Xoo ), Xanthomonas axonopodis pv. citri ( Xac ) and Pseudomonas syringae pv. actinidiae ( Psa ). Notably, compound C 8 displayed high bioactivities toward Xoo and Xac , with EC 50 values were 0.34 and 2.11 μ g mL −1 , respectively. In vivo trials revealed that compound C 8 exhibited excellent protective activities against rice bacterial blight and citrus bacterial canker at 200 μ g mL −1 , with control effectivenesses of 49.57% and 85.60%, respectively. Compound A 4 had remarkably inhibitory activity toward Psa , with an EC 50 value of 2.63 μ g mL −1 , and demonstrated outstanding protective activity with a value of 77.23% against Psa in vivo . Antibacterial mechanisms indicated that compound C 8 dose‐dependently prevented biofilm formation and extracellular polysaccharide production. C 8 also significantly weakened the motility and pathogenicity of Xoo . CONCLUSION This study contributes to the development and excavation of novel bactericidal candidates with broad‐spectrum antibacterial activity by targeting bacterial biofilm to control refractory plant bacterial diseases. © 2023 Society of Chemical Industry.