Biosurfactant from Bacillus sp. A5F Reduces Disease Incidence of Sclerotiniasclerotiorum in Soybean Crop

The present study was conducted to assess the biocontrol activity of biosurfactants obtained from Bacillus species A5F. The variables significantly influencing the production of biosurfactants under in vitro conditions were further optimized using response surface methodology. Optimal values of selected culture variables, i.e., glucose, soybean oil, and incubation time were 3.5 g l(-1), 3.5 ml l(-1), and 78 h, respectively, resulting in 2.14-fold enhancement in biosurfactant levels in 5 l fermentor. Identified biosurfactants had a significant effect on chlorophyll content, shoot biomass, number of pods, and seed weight. Biosurfactants also reduced the disease incidence in S. sclerotiorum infected soybean plants and showed antagonistic action against major phytopathogens by disrupting the hyphal cell wall. 16% reduction in ITS gene copy number was observed as compared to control with less non-target effect upon biosurfactant spray on foliar parts of soybean. Thus, the study confirms that biosurfactants from strain A5F can be used as a potent biocontrol agent to control sclerotium wilt on soybean plants.

Automated summary

This study optimized the production of biosurfactants from Bacillus species A5F under in vitro conditions and demonstrated their significant effects on chlorophyll content, shoot biomass, number of pods, and seed weight in soybean plants. The biosurfactants also showed antagonistic action against major phytopathogens and effectively controlled the incidence of S. sclerotiorum infection in soybean plants.