Unraveling 2-alkenylquinolin-1-ium derivatives as bacterial division inhibitors: bactericidal effect against food and fruits bacteria for ensuring food safety.

BACKGROUND: Phytopathogenic bacteria threaten global food security by reducing crop yields, degrading quality, and causing mycotoxin contamination. Therefore, there is an urgent need to develop highly effective bactericides with novel mechanisms of action. FtsZ (filamentous temperature-sensitive protein Z) a key protein that forms the Z-ring at the cell center to coordinate division. Although it has been recognized as an important target for novel antibacterial agents, research on its agricultural inhibitors remains relatively scarce. RESULTS: Using active fragment combination strategy, we rationally designed and synthesized a series of 2-alkenylquinolin-1-ium derivatives and rigorously evaluated their antimicrobial efficacy against three agriculturally devastating pathogens: Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Pseudomonas syringae pv. actinidiae (Psa). Among them, compound A11 exhibited exceptional antibacterial activity against all three pathogens with half-maximal effective concentration (EC50) values of 0.024, 0.074, and 3.428 μg/mL respectively. Formulation with adjuvant fatty alcohol polyglycolether (MOA-3) changed its physicochemical properties and improved foliar adhesion on the surface of leaves, increasing in vivo disease control efficacy from 44.82% to 55.41%. Mechanistic profiling revealed compound A11 binds to the interdomain cleft of XooFtsZ, inhibits XooFtsZ polymerization, and induced bacterial filamentation. Furthermore, compound A11 demonstrated favorable biosafety parameters with low phytotoxicity and negligible earthworm toxicity. CONCLUSION: This study validates FtsZ, an evolutionarily conserved bacterial division protein, as a strategic target for antimicrobial development, and identifies compound A11 as a potent, environmentally friendly FtsZ inhibitor. Beyond providing a promising XooFtsZ lead compound, this work establishes a theoretical basis for bactericide design. © 2026 Society of Chemical Industry.