Gamma-induced mutants of and display enhanced antagonistic activities and suppression of the root rot and wilt diseases in pulses.

This study aims to increase and antagonistic activity against the root rot and wilt diseases of pulses caused by and f. sp. , respectively. To increase antagonistic action, BRBac4, BRBac21, and BRAcB10 were subjected to random mutagenesis using varying doses of gamma irradiation (0.5-3.0 kGy). Following the irradiation, 250 bacterial colonies were chosen at random for each antagonistic strain and their effects against pathogens were evaluated in a plate assay. The ERIC, BOX, and random amplified polymorphic studies demonstrated a clear distinction between mutant and wild-type strains. When mutants were compared to wild-type strains, they showed improved plant growth-promoting characteristics and hydrolytic enzyme activity. The disease suppression potential of the selected mutants, . BRBac4-M6, . i BRBac21-M10, and . BRAcB10-M2, was tested in green gram, black gram, and red gram. The combined inoculation of . BRBac21-M10 and . BRAcB10-M2 reduced the incidence of root rot and wilt disease. The same treatment also increased the activity of the defensive enzymes peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase. These findings suggested that gamma-induced mutation can be exploited effectively to improve the biocontrol characteristics of and . Following the field testing, a combined bio-formulation of these two bacteria may be utilised to address wilt and root-rot pathogens in pulses.