Isolation and characterization of Bacillus isolates from Tehran and investigation of their antifungal activity against some species of Fusarium head blight fungi from Ardebil

Fusarium head blight (FHB) is economically one of the most important fungal diseases of wheat in the world. The aim of this research was to determine the antifungal metabolites of native Bacillus isolates. Bacillus strains isolated from soil of wheat and barley fields (Rural areas of southern Tehran, autumn 2012), and exhibited in vitro antagonistic activity against some Fusarium species isolated from infected wheat seeds (Wheat fields of Parsabad at Moghan, Ardebil Summer 2012). An attempt was made to partially purify and characterize the diffusible antifungal metabolite/s produced by the selected Bacillus strain in Nutrient broth medium. High Performance Liquid Chromatography (HPLC) of partially purified extract of the strain showed the presence of lipopeptide antibiotic iturin as a major peak that was comparable to that of standard iturin A (11.80 min) from Sigma–Aldrich. The structure was further confirmed by Fourier Transform-Infrared Spectrum (FTIR) and Liquid Chromatographic Mass Spectrometric (LCMS) analysis as iturin A. LCMS analysis also showed the presence of fengycin with iturin A. The genome of the selected isolate of Bacillus had shown 99/9 percent similarity by B. aryabhattai and the genome of the selected isolates of Fusarium had shown 99 percent similarity by F. graminearum. According to the results of this experiment, the antifungal effects of native Bacillus strains and also their effects in the biological control of wheat FHB disease were confirmed.