In vivo and in vitro antibacterial activity of neomycin against plant pathogenic bacteria

Abstract

The purpose of this study was to evaluate the potential of neomycin to suppress the development of economically important plant pathogenic bacteria. The in vitro antibacterial activity against Xanthomonas campestris pv. citri, Erwinia carotovora subsp. carotovora, Xanthomonas oryzae pv. oryzae and Ralstonia solanacearum was evaluated. The minimal inhibitory concentration values for the four strains were 2, 0.5, 0.25 and 2 mg l-1, respectively, and minimal bactericidal concentration values were 4, 2, 0.25 and 8 mg l-1, respectively. Furthermore, this effect of neomycin on the cell morphology of Xanthomonas oryzae pv. oryzae was investigated by transmission electron microscope, and it indicated that neomycin caused damage to bacteria, resulting in the leakage of cytoplasmic contents. Finally, the effects of neomycin on disease development and spread were determined using potted plants in the greenhouse. In vitro studies indicated that post-infectional spraying with neomycin significantly inhibited the development of citrus bacterial canker caused by X. campestris pv. citri, cabbage soft rot caused by E. carotovora subsp. carotovora, ginger bacterial wilt caused by R. solanacearum and rice bacterial blight caused by X. oryzae pv.oryzae (80.51, 77.55, 77.54 and 69.07% disease reduction, respectively). © 2011 Academic Journals.