GC-MS Analysis of antimicrobial compounds produced by Bacillus spp. against rice sheath rot pathogen Sarocladium oryzae

Bacillus species are widely exploited as biocontrol agents because of their efficiency in impeding various plant pathogens with multifaceted approach. In this study, Bacillus species were isolated from rhizosphere of rice plants in Southern districts of Tamil Nadu and assessed their potential to control the mycelial growth of Sarocladium oryzae in vitro by dual plate and paired dish technique. Bacillus subtilis strain BTK1 was confirmed by 16s rRNA and it showed effective in inhibiting mycelial growth of pathogen (75%). Moreover, vola­tile compounds emitted from the Bacillus spp. were found to inhibit the mycelial growth of S. oryzae. Further, secondary metabolites from B. subtilis (BTK1) were identified as 3-Heptanone, 5-ethyl-4-methyl-, Butanoic acid 2-methyl and 1-propanol 2,2-dimethyl acetate by gas chromatography mass spectrometry (GC-MS). Taken together, these results suggest that Bacillus subtilis (BTK1) can be used as a biocontrol agent for rice sheath rot disease caused by S. oryzae.