Assessing the antagonistic potential of entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. against soil borne pathogens of chickpea

Abstract

Chickpea (Cicer arietinum L.) is a vital pulse crop globally, but its production is increasingly threatened by soil-borne pathogens. Despite traditional disease management strategies, controlling these pathogens remains challenging. Biocontrol agents, particularly entomopathogenic fungi like Beauveria bassiana, have shown promise in managing soil-borne diseases in other crops, offering a potential sustainable solution for chickpea. To explore this potential, four isolates of Beauveria bassiana (BbR1, BbR2, BbR3, BbR4) were evaluated for their antagonistic potential against major soil-borne pathogens of chickpea. In dual culture assays, all isolates showed strong inhibitory activity against Sclerotinia sclerotiorum, with BbR2 demonstrating the highest suppression. BbR2 also showed moderate suppression of Rhizoctonia bataticola, while none of the isolates inhibited Fusarium oxysporum f. sp. ciceris, Rhizoctonia solani and Sclerotium rolfsii. All isolates, when evaluated for their extracellular hydrolytic enzyme-producing capacity, assessed positive for amylase, protease, lipase, and cellulase. Chemical profiling of ethyl acetate extracts revealed the presence of diverse secondary metabolites and the Minimum inhibitory concentration assays conducted using crude extracts showed complete inhibition of S. sclerotiorum by BbR2 and BbR3 at 4000 ppm. These findings underscore the dual mode of action of BbR2, direct antagonism via enzymatic and secondary metabolite-mediated mechanisms, highlighting its promise as a potent biocontrol agent against Sclerotinia in chickpea.