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United States Department of Agriculture

Agricultural Research Service

Research Project: Reducing Aflatoxin Contamination Using Biological Control and Crop Management

Location: U.S. Arid Land Agricultural Research Center

Title: Aspergillus flavus diversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health

Authors
item Mehl, Hillary -
item Jaime, Ramon -
item Callicott, Kenneth
item Probst, Claudia -
item Garber, Nicholas -
item Ortega-Beltran, Alejandro -
item Grubisha, Lisa -
item Cotty, Peter

Submitted to: Annals of the New York Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 30, 2012
Publication Date: December 11, 2012
Citation: Mehl, H.L., Jaime, R., Callicott, K.A., Probst, C., Garber, N.P., Ortega-Beltran, A., Grubisha, L.C., Cotty, P.J. 2012. Aspergillus flavus diversity on crops and in the environment can be exploited to reduce aflatoxin exposure and improve health. Annals of the New York Academy of Sciences. 1273:7-17.

Interpretive Summary: Aflatoxins are toxic carcinogenic fungal metabolites that contaminate food and feed crops. The most important causal agent of crop contamination is Aspergillus flavus. Strains of A. flavus vary in several characteristics including aflatoxin production with some, called atoxigenic strains, producing no aflatoxins. Biocontrol through application of atoxigenic strains is an effective management strategy for reducing the prevalence of aflatoxin producers and thereby the severity of crop contamination. Prevalence of specific strains is dictated by competition among A. flavus under variable biotic (i.e. crop) and abiotic (i.e. climate) conditions. Characterizing diversity within A. flavus is important for identifying optimal strains for biocontrol and identifying agronomic practices that result in less aflatoxigenic fungal communities. Management strategies based on modification of A. flavus populations improve safety of food by reducing human exposure to aflatoxins.

Technical Abstract: Humans and animals are exposed to aflatoxins, toxic carcinogenic fungal metabolites, through consumption of contaminated food and feed. Aspergillus flavus, the primary causal agent of crop aflatoxin contamination, is composed of phenotypically and genotypically diverse vegetative compatibility groups (VCGs). Molecular data suggest VCGs largely behave as clones with certain VCGs exhibiting niche preference. VCGs vary in aflatoxin-producing ability, ranging from highly aflatoxigenic to atoxigenic. Prevalence of individual VCGs is dictated by competition during growth and reproduction under variable biotic and abiotic conditions. Agronomic practices influence structures and average aflatoxin-producing potentials of A. flavus populations and, as a result, incidences and severities of crop contamination. Application of atoxigenic strains has successfully reduced crop aflatoxin contamination across large areas in the United States. This strategy uses components of the endemic diversity to alter structures of A. flavus populations and improve safety of food, feed, and the overall environment.

Last Modified: 11/26/2014
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