ARS | Publication request: Relationship of substrate and surfactin production by Bacillus mojavensis strains and their antagonistical response to Fusarium verticillioides

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 7, 2010
Publication Date: August 7, 2010
Citation: Bacon, C.W., Hinton, D.M., Snook, M.E. 2010. Relationship of substrate and surfactin production by Bacillus mojavensis strains and their antagonistical response to Fusarium verticillioides. American Phytopathological Society Annual Meeting. August 7-10,2010. Charlotte, NC. 100(6):S10.

Technical Abstract: The endophytic bacterium, Bacillus mojavensis, RRC 101 controls fungal diseases in maize and other plants. The bacterium and its cultural extracts have been shown to be antagonistic to the pathogenic and mycotoxic fungus, Fusarium verticillioides. An antifungal lipopeptide produced by B. mojavensis strains in culture was identified as surfactin, a biosurfactant. HPLC-MS spectra analyses indicated that B. mojavensis, RRC 101, produced Leu7-surfactin as the major surfactin, although in the surfactin complex C-14 and C-15 isoforms dominated. Bacterial strains and culture media can have a direct effect on antifungal antagonism, surfactant production, and metabolic utilization by strains of B. mojavensis. In this investigation, B. mojavensis strains were screened to determine the effects of media on antagonism to F. verticillioides, surfactant production, and metabolic utilization of key substrates. The data indicated that the bacterial strains showed zero to high levels of antagonisms, which were not correlated with total surfactin production. Thus, the data suggest that either there are synergistic effects from specific isoforms produced on agar media or there are also some unidentified biosurfactants or other inhibitory compounds yet determined.