Bacillus spp. were cultivated routinely on Luria broth (LB) medium solidified with 1.5% agar and fermented in Landy medium. Nutrient agar (NA) medium was used to culture X. oryzae pv. oryzae and X. oryzae pv. oryzicola. When required, antibiotics were added to the following final concentrations: ampicillin 100 μg/ml, chloramphenicol 5 μg/ml, rifampicin 100 μg/ml and erythromycin 10 μg/ml.