The aims of this study were to select antagonistic microorganisms showing strong antifungal activity against a fusarium head blight pathogen, Fusarium graminearum, to identify the selected microorganism, to characterize the active compounds, and to evaluate the efficiency of this strain to control f...
The aims of this study were to select antagonistic microorganisms showing strong antifungal activity against a fusarium head blight pathogen, Fusarium graminearum, to identify the selected microorganism, to characterize the active compounds, and to evaluate the efficiency of this strain to control fusarium head blight (FHB) on wheat. For selecting antagonistic microorganisms against F. graminearum, a total of 500 Bacillus strains were tested for their inhibitory activity against mycelial growth and spore germination of the fungal pathogen. Since Bacillus amyloliquefaciens JCK-12 showed the strong antifungal activities, antifungal compounds were isolated from the fermentation broth of the antagonistic bacterium through butanol extraction, silica gel column, Sephadex LH-20 column, ODS column and preparative TLC under the guidance of spore germination inhibition bioassay. The purified antifungal metabolites were identified as iturin A, which is consisting of A2, A3, and A4 (or A5) based on LC-MS-MS. Iturin A highly inhibited the macroconidia germination of F. graminearum by 90% at a concentration of 30 μg ml-1. In addition, strain JCK-12 produced fengycin A and surfactin, which alone did not display spore germination inhibitory activity at concentrations less than 30 μg ml-1. However, the mixture of iturin A, fengycin A, and surfactin showed the synergy effect in the macroconidia germination test. The fermentation broth of B. amyloliquefaciens JCK-12, at 5-fold dilution, reduced the development of FHB on wheat by 43.0% in greenhouse condition and 56.3% in field condition. Also the wettable powder type formulation of B. amyloliquefaciens JCK-12, at 500-fold dilution, reduced the development of FHB on wheat by 64.1% in field condition. The results indicate that B. amyloliquefaciens JCK-12 could be used as a promising biocontrol agent for the control of FHB in agriculture.
The aims of this study were to select antagonistic microorganisms showing strong antifungal activity against a fusarium head blight pathogen, Fusarium graminearum, to identify the selected microorganism, to characterize the active compounds, and to evaluate the efficiency of this strain to control fusarium head blight (FHB) on wheat. For selecting antagonistic microorganisms against F. graminearum, a total of 500 Bacillus strains were tested for their inhibitory activity against mycelial growth and spore germination of the fungal pathogen. Since Bacillus amyloliquefaciens JCK-12 showed the strong antifungal activities, antifungal compounds were isolated from the fermentation broth of the antagonistic bacterium through butanol extraction, silica gel column, Sephadex LH-20 column, ODS column and preparative TLC under the guidance of spore germination inhibition bioassay. The purified antifungal metabolites were identified as iturin A, which is consisting of A2, A3, and A4 (or A5) based on LC-MS-MS. Iturin A highly inhibited the macroconidia germination of F. graminearum by 90% at a concentration of 30 μg ml-1. In addition, strain JCK-12 produced fengycin A and surfactin, which alone did not display spore germination inhibitory activity at concentrations less than 30 μg ml-1. However, the mixture of iturin A, fengycin A, and surfactin showed the synergy effect in the macroconidia germination test. The fermentation broth of B. amyloliquefaciens JCK-12, at 5-fold dilution, reduced the development of FHB on wheat by 43.0% in greenhouse condition and 56.3% in field condition. Also the wettable powder type formulation of B. amyloliquefaciens JCK-12, at 500-fold dilution, reduced the development of FHB on wheat by 64.1% in field condition. The results indicate that B. amyloliquefaciens JCK-12 could be used as a promising biocontrol agent for the control of FHB in agriculture.
주제어
#Fusarium graminearum Bacillus amyloliquefaciens
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