Evaluating Efficacy of Biosurfactants from Bacterial Isolates in Conferring Protection against Rhizoctonia and Sclerotium Infection in Wheat and Peanut Plants

This work out in collaboration between both the authors. Author SP conceived and designed the study. Author JF carried out the experiments and author SP performed the analysis of data. Author JF wrote the first draft of the manuscript and managed the literature searches. Author SP edited and proofread the final manuscript. Both authors read approved the final ABSTRACT Aims: To isolate biosurfactant producers from natural habitat and to test the antimicrobial activity of the extracted biosurfactant against fungal plant pathogens. activity. Potent biosurfactant producing isolates were biochemically characterized and identified up to genus level using Bergey’s manual. Biosurfactant was extracted by chloroform: Methanol method. Characterization of extracted biosurfactant was done using blue agar plate and orcinol assay. Agar well diffusion method was used to test antimicrobial activity of biosurfactants. Ability of the biosurfactants to provide protection against fungal plant pathogens was demonstrated in vivo using wheat and peanut plant seedlings. Results: Three isolates BMW1, BMW2 and BPS1 showing good biosurfactant activity were selected for biosurfactant production. They belonged to genus Pseudomonas, Bacillus and Micrococcus . Extraction of culture supernatant gave white residue which was used in further studies as biosurfactant. The biosurfactant produced by isolates BMW1 and BPS1 was glycolipid anionic biosurfactant while CTAB medium indicated non-ionic nature of biosurfactant from BMW2. Biosurfactant extracted from all three isolates showed good antimicrobial activity. Biosurfactant produced by BMW1 and BPS1 most effectively protected peanut plantlets from Sclerotium rolfsii infection and wheat plantlets from Rhizoctonia solani infection respectively. Conclusion: Our study suggested a strategy for eliminating plant pathogenic fungi by using microbial biosurfactants.