Antagonistic effect of Pseudomonas fluorescens against Fusrium oxysporum f.sp. Ciceri causing wilt in chickpea

Biocontrol agent, Pseudomonas fluorescens which inhibit the growth of fungal pathogen Fusarium oxysporum f. sp. ciceri in vitro on potato dextrose agar + Kings'B (1:1) medium, were evaluated for their potential to produce various extra cellular enzymes at 6 days after inoculation (DAI). The highest extra cellular activities of cellulase and polygalacturonase (PG) were seen in the culture medium of F. oxysporum compared to culture media of sole F. oxysporum and P. fluorescens treatments. Among the ten isolates of biocontrol agents, Pf-3 showed highest per cent inhibition of growth of the pathogen on culture medium. The per cent inhibition was positively correlated with extra cellular specific activities of protease, chitinase and β-1, 3-glucanase. The possible involvements of these enzymes in the antagonistic interaction between P. fluorescens and F. oxysporum f. sp. ciceri were observed. This suggested that isolates of P. fluorescens was suitable to be used in biological control of plant pathogen F. oxysporum f. sp. ciceri. Moreover, the substance like salicylic acid, siderophore and IAA production by Pf-3 exhibited its efficacy to work as biocontrol agent as well as PGPR.