Activity of Brevibacillus brevis strain LABIM17 against Xanthomonas euvesicatoria pv. euvesicatoria and control of bacterial spot of tomato

The aim of this study was to determine the activity of Brevibacillus brevis strain LABIM17 against Xanthomonas euvesicatoria pv. euvesicatoria and the control of bacterial spot on tomato. The antimicrobial activity of the strain LABIM17 against X. euvesicatoria pv. euvesicatoria strain 75-3 was evaluated by the agar diffusion method, the pour plate. The minimum inhibitory concentration (MIC) for the growth of the strain 75-3 was 500 µg mL −1 of the LABIM17 extract, the lyophilized cells free supernatant (CFS). Tomato plants sprayed with LABIM17 suspension at the concentrations of 3.4 × 10 7 and 1.7 × 10 7 CFU mL −1 and inoculated three days later with strain 75-3 showed reduction in the severity of the disease. Further, the plants that received these applications of strain LABIM17 presented reduction of 80 and 86%, respectively, in bacterial spot severity, the same level of disease reduction provided by the commercial chemical inducer acibenzolar-S-methyl. To our knowledge, this is the first report of the antimicrobial activity of B. brevis strain LABIM17 against X. euvesicatoria pv. euvesicatoria . The characterization of this antimicrobial activity may bring new insights on the mechanisms of control of bacterial spot in tomato by this promising biocontrol agent.