New Axially Chiral Molecular Scaffolds with Antibacterial Activities against Xanthomonas oryzae pv. oryzae for Protection of Rice

A new class of axially chiral thiazine molecules were constructed and showed promising antibacterial activities againstthe plant pathogenXanthomonas oryzaepv.oryzae(Xoo). The axial chiralities of these compounds (R-orS-atropisomer) showedclear impacts on the in vitro inhibitory activities againstXoo. An optimal molecule of this class with the (S)-axially chiralconfiguration was identified to exhibit inhibitory activity againstXoowith an EC50value of 4.18 mu g/mL. This inhibition efficiency issuperior to that of two commercial antibacterial agrochemicals, thiodiazole-copper and bismerthiazol, as the positive controls. Thishit compound also performed better than the controls in our in vivo studies. Preliminary mechanistic studies via scanning electronmicroscopy images showed that our hit compound at a concentration of 10 mu g/mL destroyed the bacterial integrity ofXoo. Label-free quantitative proteomics analysis indicated that a total of 366 differentially expressed proteins of the rice plants were significantlyinfluenced in the presence of our hit molecule.

Automated summary

A new class of axially chiral thiazine molecules were constructed and showed promising antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo). The axial chiralities of these compounds had clear impacts on the inhibitory activities against Xoo. The optimal molecule exhibited superior inhibitory activity and outperformed the controls in in vivo studies.