Isolation and optimization of Bacillus sp. from corn planting soil to inhibit Fusarium moniliforme causing stalk rot disease in corn

Corn is an economic crop. Nowadays, plant diseases such as Fusarium stalk rot have been found in corn cultivation. Chemical fungicides are widely used to inhibit this fungus. However, using biological controls is one of the approaches for preventing and solving the problem of plant diseases. Soil samples were collected from corn planting soils using random sampling techniques. The morphological characteristics of the 17 isolated bacteria were studied under a microscope. Isolate SCFPSU17 was evaluated for its ability to inhibit Fusarium moniliforme that cause stalk rot disease in corn. After identification, the results revealed that DNA sequencing of SCFPSU17 was similar to Bacillus sp. with percentage similarity of 99.86%. The culture filtrate of Bacillus sp. showed the best inhibition of F. moniliforme at 38.63%. Then, the optimal conditions of Bacillus sp. isolated SCFPSU17 were tested, including the optimal medium, optimal pH of medium, and optimal temperature of culture and cultivation time. The result found that Bacillus sp. isolated SCFPSU17 in nutrient broth pH 8 at 30°C for 36 hours demonstrated the most effective inhibition of F. moniliforme, up to 70%. From this result, bioactive agents from Bacillus sp. for inhibiting plant fungal pathogens may be an important discovery to develop bioactive compounds production for sustainable agriculture in the future.