Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 22, 2004
Publication Date: N/A
Technical Abstract: Toxic fungal metabolites known as mycotoxins contaminate maize grain produced throughout the world and represent a major food safety problem. While conventional breeding has produced commercial maize hybrids with substantial resistance to Fusarium graminearum (deoxynivalenol and zearalenone), efforts to produce hybrids with adequate resistance to Aspergillus flavus (aflatoxin) and Fusarium verticillioides (fumonisin) have proven more difficult, and effective practical control practices are lacking. As 'gatekeepers' to food safety, the food and feed industry must continue to rely on convenient, accurate and sensitive methods for detection of the major mycotoxins in grain. Seeds highly contaminated with aflatoxin or fumonisin are unevenly distributed in a seed lot and may may be concentrated in a very small percentage of the product. Because mycotoxin-contaminated grains tend to be less dense than grains not infested with molds, these grains may be separated through physical methods of grain cleaning. Furthermore, given color and biochemical changes in mycotoxin contaminated grains, electronic color sorters have the potential to segregate these from uncontaminated grains. Microbial ecology has provided the foundation for significant achievements during the past decade including: (1) Bacillus thuringiensis or 'Bt transgenic corn' reduced insect damage to the corn kernels caused by the European corn borer (Ostrinia nubilalis) indirectly reducing Fusarium kernel rot and fumonisin contamination; (2) competitive exclusion using nontoxigenic strains of A. flavus or F. verticillioides has been shown to reduce aflatoxin or fumonisin, respectively, in corn; (3) 'protective endophytes' of corn interfere with A. flavus and F. verticillioides kernel infection or were the source of genes inserted to detoxify fumonisin in planta. Microbial endophytes of cereals represent underexplored sources of antifungal proteins and metabolites that can suppress fungal growth or silence genes critical to mycotoxin synthesis while being adapted to function in planta. Ecological information will remain central to the development of practical knowledge and technologies that will enable us to eliminate mycotoxins impacting the cereal grain industry.