Characterization of endophytic Bacillus subtilis for the management of Rhizoctonia bataticola causing root rot in cotton

The present study on the identification of volatiles and secondary metabolites for endophytic Bacillus subtilis was carried out for the management of soil borne diseases of cotton using native isolates of endophytic Bacillus sp. A total of 20 endophytic bacteria were isolated from different cotton plant origin. Biochemical characterization of bacterial endophytes revealed that all the 20 isolates were found to be Bacillus sp. It was also confirmed through Polymerase Chain Reaction (PCR) by amplifying an amplicon of 520 bp of 16s rDNA of Bacillus sp. Among the twenty isolates of Bacillus sp. tested for their antagonistic activity against Rhizoctonia bataticola by dual culture, ESBs 19 significantly exerted the highest of 57.91% reduction of mycelial growth. Application of endophytic Bacillus subtilis (5 g kg⁻¹) as seed treatment reduced the incidence of wilt disease by 65.57% under field conditions against the control. In the present study the MIDI Sherlock System identified the bacterial antagonist as Bacillus subtilis by fatty profiles, with a degree of similarity index (SI) of 0.822, with 0.12 separation between the first and second choice.