Received: 07-08-2023 / Accepted: 26-01-2024
Alternarialeaf spot on cucumber causes serious damage to marketable fruit yield and quality. The study was carried out to select bacterial strains from the cucumber rhizosphere soil with antagonistic activity against Alternariaalternata. The isolates were evaluated for their antifungal activity by dual culture method. The antagonistic isolates were investigated for their ability to produce hydrolytic enzymes and siderophore. The antifungal activity of volatile organic compounds was evaluated by the Petri dish inversion method. Twelve isolates exhibited antagonism against A. alternata. Growth inhibition of A. alternataby these isolates ranged from 9.7 to 47.8%. Eight isolates showed the ability to produce siderophore. All isolates were capable of producing hydrolytic enzymes (β-1,3-glucanase, chitinase, protease). Chitinase had a strong correlation with the ability to inhibit the growth of the pathogenic fungus (P <0.05). Volatile organic compounds of 12 antagonistic strains showed the ability to inhibit the growth of spores (61.8-95.2%) and mycelium (58.9-79.7%) of A. alternataThe results of this study indicated the potential of rhizobacteria in controlling A. alternatacausing leaf spot in cucumbers.