Bio-Prospecting of Endospore-Based Formulation of Bacillus sp. BST18 Possessing Antimicrobial Genes for the Management of Soil-Borne Diseases of Tomato

Tomato is affected by various diseases which cause economical loss to the farming community. In the present study, twenty isolates of Bacillus sp. were isolated from the rhizosphere of tomato and screened against soil-borne pathogens viz., Pythium aphanidermatum No.5, Fusarium oxysporum f. sp. lycopersici No. FOL-8, and Sclerotium rolfsii No. S-MK in tomato. The results revealed that three Bacillus sp. viz., BST8, BST18, and BST19 were promising in reducing the mycelial growth of the pathogens (up to 48% reduction) when compared to control under in vitro. The isolates possessed antimicrobial peptide genes which were detected through PCR. Novel compounds and secondary metabolites responsible for antifungal action were identified through GC-MS and FTIR analysis. Endospores have been isolated from the Bacillus sp. BST18 and standardized for the development of formulation. Pot culture experiment revealed sequential application of endospore-based bioformulation as seed treatment, (10 ml/kg), seedling dip (10 ml/lit), soil application on 30 days (100 ml/pot) along with foliar spray (0.2%) on 60 days recorded the lowest disease incidence of wilt (9.5%), and collar rot (11.5%) as against 65.5% and 75%, respectively, in the inoculated control. Field experiments revealed sequential application of endospore-based formulation of Bacillus sp. BST 18 as seed treatment, (10 ml/kg), seedling dip (10 ml/lit), soil application (400 ml/acre) at 30 days after transplantation (DAT) along with foliar spray (0.2%) on 60 DAT recorded the lowest wilt disease incidence of 15.9717.07 percent as against 49.7751.10 percent in the control.