Design and research of new virulence factor inhibitors for plant bacterial disease control

In this work, various chalcone derivatives incorporating piperazine-isopropanolamine were elaborately designed and synthesized. The antibacterial efficacy revealed that compound Z6 showed notable biological activity, with a median effective concentration (EC₅₀) of 0.29 mg/L against Xanthomonas oryzae pv. oryzae (Xoo) in vitro, which is around 200 times higher than thiodiazole copper (TC, 91.00 mg/L). Similarly, Z21 exhibited a strong biological response (EC₅₀ = 0.83 mg/L) against Xanthomonas axonopodis pv. citri (Xac), outperforming TC (EC₅₀ = 114.60 mg/L). Results of bioactivity test in vivo demonstrate that Z6 displayed significantly better curative and protective activities (51.5 %, 47.9 %) than TC (47.9 %, 30.5 %) against rice bacterial leaf blight (BLB). Further biochemical studies indicates that Z6 targeted multiple virulence factors and repressed the release of essential nutrients required for bacterial proliferation, thereby disrupting the reduction of cell membrane content of the pathogenic bacteria. According to the research, chalcone derivatives containing piperazine-isopropanolamine have potential to be antibacterial candidates.