Ralstonia solanacearum (R. solanacearum) is one of the most devastating bacterial pathogens and leads to serious economic losses in crops worldwide. In this study, the antibacterial activities of novel plant-derived coumarins against R. solanacearum and their underlying mechanisms were initially investigated. The bioactivity assay results showed that certain coumarins had significant in vitro inhibitory effects against R. solanacearum. Notably, 6-methylcoumarin showed the best in vitro antibacterial activity with 76.79%. Interestingly, 6-methylcoumarin was found to cause cell elongation, disrupt cell division, and suppress the expression of the bacterial division protein coding genes ftsZ. Compared with the control treatment, the ∆ftsZ mutant inhibited bacterial growth and caused the bacteria to be more sensitive to 6-methylcoumarin. The application of 6-methylcoumarin effectively suppressed the development of tobacco bacterial wilt in pot and field experiments, and significantly reduced the bacterial population in tobacco stems. The control efficiency of 6-methylcoumarin treatment was 35.76%, 40.51%, 38.99% at 10, 11, and 12 weeks after tobacco transplantation in field condition. All of these results demonstrate that 6-methylcoumarin has potential as an eco-friendly and target specificity agent for controlling tobacco bacterial wilt.

Ralstonia solanacearum ( R. solanacearum ) 是最具破坏性的细菌病原体之一，导致全球作物严重经济损失。在这项研究中，初步研究了新型植物源香豆素对青枯菌的抗菌活性及其潜在机制。生物活性测定结果表明，某些香豆素对青枯菌具有显着的体外抑制作用。值得注意的是，6-甲基香豆素表现出最好的体外抗菌活性，达到76.79%。有趣的是，6-甲基香豆素被发现会导致细胞伸长，破坏细胞分裂，并抑制细菌分裂蛋白编码基因ftsZ的表达. 与对照处理相比，Δ ftsZ突变体抑制细菌生长并使细菌对 6-甲基香豆素更敏感。6-甲基香豆素的施用在盆栽和田间试验中有效抑制了烟草青枯病的发展，显着降低了烟梗中的细菌数量。6-甲基香豆素处理在大田条件下烟草移植后10、11、12周的防效分别为35.76%、40.51%、38.99%。所有这些结果表明，6-甲基香豆素具有作为控制烟草青枯病的环保和靶向特异性剂的潜力。