Submitted to: African Journal of Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/24/2003
Publication Date: 12/31/2003
Citation: Brown, R.L., Chen, Z.-Y., Menkir, A., Cleveland, T.E. 2003. Using biotechnology to enhance host resistance to aflatoxin contamination of corn. African Journal of Biotechnology. 2:557-562. Interpretive Summary: The fungus named Aspergillus flavus produces a poison called aflatoxin when it infects corn kernels. Aflatoxin prevents the corn from being used commercially. T he best strategy for controlling this problem is to develop corn that is resistant to aflatoxin contamination, through the expression of different resistance traits. Molecular biology is being used in different ways to aid in the incorporation of resistance traits into corn. New tools for field inoculation and laboratory screening of corn using genetically-altered fungi are enhancing breeders' ability to separate resistant from susceptible corn lines. Analyzing corn populations with molecular markers may facilitate the incorporation of several different resistance traits into lines with good agronomic characteristics such as high yield. Proteomics has significantly enhanced the ability to identify proteins that may play a role in resistance. These findings suggest that resistant corn lines may be developed, through breeding or genetic engineering, that are capable of resisting infection by Aspergillus flavus and/or aflatoxin contamination. This could lead to future savings of millions of dollars and increased safety for food and feeds, as a result of the control of corn contamination by aflatoxin.
Technical Abstract: Host resistance is the most widely-explored strategy for eliminating aflatoxin contamination by Aspergillus flavus. Breeding strategies for developing resistant corn germplasm have been enhanced by the development of new screening tools for field inoculation and for laboratory screening. RFLP analysis of corn populations has highlighted the possibility that different resistance traits can be successfully pyramided into agronomically-useful germplasm, while proteomics has impacted the identification of proteins associated with resistance (RAPs). The identification of RAPs has also been enhanced by the discovery of near-isogenic corn lines in progeny generated in a West African breeding program. The characterization of genes of the aflatoxin biosynthetic pathway has provided a foundation for a genomics investigation aimed at understanding the biochemical function and genetic regulation of aflatoxin biosynthesis. Successful inhibition of aflatoxin elaboration may require not only the action of antifungal compounds, but of compounds that block biosynthesis of toxins as well.