Discovery of DNA Gyrase as a Promising Target against Phytopathogenic Bacteria

The growing resistance of phytopathogenic bacteria highlights the need for new bactericides. DNA gyrase, essential in bacteria but absent in plants and animals, is an underexploited target for agricultural bactericides. Here, we modeled the <i>Ralstonia solanacearum</i> GyrA-GyrB-DNA complex using AlphaFold3 and conducted structure-based virtual screening of 1.27 million compounds. Among 100 tested candidates, GI-A14 showed potent, broad-spectrum antibacterial activity against <i>R. solanacearum</i>, <i>Pseudomonas syringae</i> pv tomato, and <i>Xanthomonas oryzae</i> pv oryzae, with minimum inhibitory concentrations of 1-4 μg/mL. Enzymatic assays confirmed that GI-A14 stabilizes the gyrase-DNA cleavage complex, indicating a DNA-interfacial inhibition mechanism. Furthermore, GI-A14 significantly attenuated the pathogenicity and biofilm formation of <i>R. solanacearum</i>. In planta, GI-A14 provided strong protection against bacterial wilt, speck, and blight, outperforming the commercial agent zhongshengmycin. These results establish DNA gyrase as a viable molecular target for plant disease control and identify GI-A14 as a promising lead compound for next-generation green bactericides.