Journal of Agronomy and Field Innovations

Background: Sclerotium rolfsii Sacc. causes stem rot. is a serious soil-borne constraint to groundnut (Arachis hypogaea L.) production and can cause yield losses ranging from 25 to 80% under conducive conditions. Chemical fungicides have limited residual activity and are of concern from an environmental sustainability perspective so biologically based management alternatives are needed.
Objectives: To assess the biocontrol potential of Bacillus velezensis strain BV-TNAU17 against S. rolfsii under in vitro and pot and field conditions. To determine the antagonistic mechanisms such as lipopeptide production, hydrolytic enzyme activity and induced systemic resistance. To evaluate the plant growth promoting properties under pathogen stress.
Materials and Methods: To evaluate the biocontrol potential of Bacillus velezensis strain BV-TNAU17 against S. rolfsii under in vitro and pot and field conditions. To study the antagonistic mechanisms such as lipopeptide production, hydrolytic enzyme activity and induced systemic resistance. For determination of the plant growth promoting properties under pathogen stress.
Results: BV-TNAU17 inhibited the growth of S. rolfsii mycelium by 72.4% in dual culture and produced iturin A, fengycin and surfactin lipopeptides as identified by HPLC-MS analysis. Under field conditions, seed treatment with BV-TNAU17 plus soil drench reduced the disease incidence by 68.3%, disease severity by 71.6% and increased the pod yield by 44.2% over pathogen inoculated control. BV-TNAU17 treated plants showed significant increase in activities of defense enzymes (peroxidase, polyphenol oxidase and phenylalanine ammonia-lyase) suggesting induced systemic resistance. Rhizosphere microbial biomass carbon increased by 38.7% and urease activity by 31.4% relative to untreated inoculated controls.
Conclusion: B. velezensis BV-TNAU17 exhibited multi-faceted biocontrol mechanisms and plant growth-promotion properties, which altogether suppress S. rolfsii and enhance the groundnut productivity. This strain has a promising prospect to be a part of integrated disease management strategies for sustainable groundnut cultivation.