In Vitro Antagonistic Antifungal-Activity of Streptomyces Isolate 339 Against Magnaporthe oryzae

Biological control offers an environmentally friendly alternative to the use of antimicrobials for controlling plant diseases. A collection of about 100 Actinomycete strains was screened for the ability to produce metabolites that inhibit Magnaporthe oryzae growth in vitro. The Streptomyces isolate 339 showed strong in vitro antagonistic activity against M. oryzae in Agar disc and Well-diffusion methods by producing extracellular antifungal metabolites. The isolate No. 339 was propagated in submerged cultures and active crude was prepared upon which some biological characterization performed. Antifungal activity of this antagonist was of fungistatic type on the pathogen. The active metabolite (s) is polar, soluble in H₂O and methanol but insoluble in chloroform, dichloromethane or hexane. Thermal inactivation point of active phase of Streptomyces isolate 339 was 80°C. Antifungal gene from isolate 339 may be a useful candidate for genetic engineering of agriculturally important crop for increased tolerance against M. oryzae.