Allicin‐inspired disulfide derivatives containing quinazolin‐4( <scp> 3 <i>H</i> </scp> )‐one as a bacteriostat against <i>Xanthomonas oryzae</i> pv. <i>oryzae</i>

Abstract

Abstract BACKGROUND Plant bacterial diseases have seriously affected the yield and quality of crops, among which rice bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae has seriously affected the yield of rice. As plant‐pathogenic bacteria gradually become resistant to existing bactericides, it is necessary to find effective bactericides with novel structures. RESULTS Herein, a series of compounds containing quinazolin‐4(3 H )‐one and disulfide moieties were designed and synthesized using a facile synthetic method. The bioassay results revealed that most target compounds possessed noticeable antibacterial activity against Xanthomonas oryzae pv. o ryzae . Particularly, compound 2‐(butyldisulfanyl) quinazolin‐4(3 H )‐one (1) exhibited remarkable antibacterial activity with the half effective concentration (EC 50 ) of 0.52 μg mL −1 . Additionally, compound 1 was confirmed to inhibit the growth of the bacteria, change the bacterial morphology, and increase the level of reactive oxygen species. Proteomics, and RT‐qPCR analysis results indicated that compound 1 could downregulate the expression of Pil‐Chp histidine kinase chpA encoded by the pilL gene, and the potting experiments proved that compound 1 exhibits significant protective activity against BLB. CONCLUSIONS Compound 1 may weaken the pathogenicity of Xanthomonas oryzae pv. oryzae by inhibiting the bacterial growth and blocking the pili‐mediated twitching motility without inducing the bacterial apoptosis. This study indicates that such derivatives could be a promising scaffold to develop a bacteriostat to control BLB. © 2022 Society of Chemical Industry.