Antifungal Activity of Secondary Metabolites Produced by Pseudomonas fluorescens

Thirty isolates of Pseudomonas fluorescens obtained from citrus rhizosphere were tested for antifungal activity against Phytophthora spp., P. fluorescens isolate Pf₂₀ was found efficient in inhibiting the mycelial growth upto 38.88%. The antifungal compounds were extracted with equal volume of ethyl acetate and were tentatively identified on thin layer chromatography (TLC) at R_f 0.28. The antifungal compounds extracted from P. fluorescens at 5% were found inhibitory to the growth of Rhizoctonia solani (42.79%), Phytophthora parasitica (28.57%), P. palmivora (25.98%) and Fusarium solani (20.45%). In case of HPTLC analysis the characteristic colour and fluorescent band after derivatization with anisaldehyde reagent proved the presence of secondary metabolites in crude extract.