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چکیده
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In this study, four endophytic bacterial strains were isolated from healthy strawberry plant and were identified as Bacillus spp. strain YN8, Bacillus spp. strain LN57, Bacillus spp. strain MN17 and Pseudomonas aeruginosa strain EN18 based on phenotypic, biochemical characteristics and molecular phylogenetic analysis. Then, their effects as biocontrol agents against Colletotrichum nymphaeae causal agent of strawberry anthracnose were investigated under in vitro, in vivo and greenhouse conditions. All strains decreased growth of C. nymphaeae in vitro tests. Disease severity on inoculated strawberry fruits and seedlings were reduced significantly more than control which can be due to the secretion of enzymes and antifungal metabolites. In addition, the toxin produced by pathogen was extracted and purified by thin layer chromatography (TLC) and its chemical structure was characterized by Fourier transform infrared (FT-IR), H and C Nuclear magnetic resonance (NMR) spectra (400 and 100 MHz). The ability of detoxification of extracted toxin by endophytic bacterial strains was performed using bioassay tests and spectral analysis. Bioassay tests of fungal toxin treated with the strains MN17 and EN18 did not display any symptoms on strawberry leaves. Also, spectral analysis indicated various absorption coefficients by each bacterial strain that corresponds with bioassay tests.
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