Submitted to: International Allelopathy Congress
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2008
Publication Date: 9/21/2008
Citation: Bacon, C.W., Hinton, D.M., Glenn, A.E., Macias, F.A., Marin, D. 2008. Bacillus mojavensis transforms BOA into fungitoxic APO in the presence of fusarium verticillioides. International Allelopathy Congress. Sept. 21-26,2008. Saratoga Springs, NY. Interpretive Summary: Abstract - no summary required
Technical Abstract: Benzoxazolin-2(3H)-one (BOA) is an important transformation product of cyclic hydroxamic acids of maize. This natural product has the potential of providing resistance to maize from Fusarium verticillioides, a major pathogen of maize. However, it has been demonstrated that this maize pathogen and others are capable of detoxifying the benzoxazolinones, producing less toxic N-(2-hydroxyphenyl) malonamic acid (HPMA) and 2-acetamidophenol via the intermediate 2-aminophenol (AP). A potential biocontrol bacterium for this pathogen on maize is Bacillus mojavensis, an endophytic species that confers growth enhancements and disease protection. Since, the benzoxazolinones are known to be toxic to both Gram negative and positive bacteria, an in vitro study of the effects of BOA on this endophytic species was examined. The study illustrated a curious interaction of BOA and its decomposition products in the presence of the bacterium and F. verticillioides. The results showed that apparently the bacterium is tolerant to BOA, and that there was an increased production of a red pigment on BOA amended media when wild type and specific genetic crosses of F. verticillioides were co-cultured with this bacterium. The red pigment was identified as 2-amino-3H-phenoxazin-3-one (APO), which is a highly toxic and stable product of AP. The results indicate that the bacterium directly or indirectly interacts with the fungus preventing it from transforming BOA to the non-toxic HPMA, resulting in an accumulation of APO, which is very toxic to F. verticillioides and other organisms, but nontoxic to B. mojavensis. Thus, an enhanced biocontrol is suggested from this in vitro study.