Submitted to: Phytopathology
Publication Type: Abstract only
Publication Acceptance Date: 6/1/2005
Publication Date: 7/30/2005
Citation: Bacon, C.W., Hinton, D.M. 2005. Tentative identification of bacillus mojavensis antifungal inhibitor [abstract]. Phytopathology. 95(6):S5. Interpretive Summary: Abstract - no summary.
Technical Abstract: The nature of an inhibitory substance produced from an endophytic species of bacteria, Bacillus mojavensis, that readily forms positive associations with several plants, was examined. Several isolates have been reported to be plant-growth promoters, plant-health enhancers and successful in preventing the development of plant diseases. B. mojavensis RRC 101 exhibited strong antagonism to Fusarium verticillioides and other pathogenic fungi by producing zones of inhibition when bioassayed on nutrient agar. The inhibitor caused enlarging of hyphae and conidia, degradation of cellular matrix and cell walls of this and other sensitive fungi. The chemical identity of the antagonistic compound is unknown, but assumed to be a type of biosurfactant, a cyclic lipoprotein characteristic of inhibitor produced by Bacillus species. We examined cultures of B. mojavensis for similar lipoproteins. The antifungal fraction produced in 5-7 day-old liquid culture medium was subjected to precipitation at pH 2, extraction with both methanol or methylene chloride, and its physical and chemical properties determined. This substance was assayed against F. verticillioides and compared with the inhibition produced from authentic standards of iturin A and surfactin, two known fungal inhibitory biosurfactants.