First report of antifungal properties of a new strain of Streptomyces plicatus (Strain101) against four Iranian phytopathogenic isolates of Verticillium dahliae, a new horizon in biocontrol agents

Abstract

This is the first report on antifungal activity of a new strain of Streptomyces plicatus (strain101) against four Iranian phytopathogenic isolates of Verticillium dahliae. In the recent decades, biological control of plant diseases has received more attention mainly as a response to public concern about the use of hazardous chemicals in the environment. Soil Actinomycetes particularly Streptomyces spp. enhance soil fertility and have antagonistic activity against wide range of soil-borne plant pathogens. In search for metabolites of soil Actinomycetes having antifungal activity against four isolates of the cosmopolitan pathogen, Verticillium dahliae Klebahn, 110 isolates were screened. Among all, strain101 that was identified as a new strain of S. plicatus, showed high level of activity in Agar disk and Well-diffusion methods. S. plicatus was propagated in submerged cultures and active crude was prepared upon which some biological characterizations performed. The active metabolite (s) is polar, soluble in H2O and methanol but insoluble in chloroform, dichloromethane or hexane. Antifungal activity composed of two types, mycelial inhibition, inhibition of microsclerotia and melanin production. Antifungal gene from S. plicatus Strain 101 may be a useful candidate for genetic engineering of agriculturally important crop plants for increased tolerance against V. dahliae