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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Maize with Enhanced Resistance to Aflatoxin and Insects

Location: Corn Host Plant Resistance Research

Title: Toward elucidation of genetic and functional genetic mechanisms in corn host resistance to Aspergillus flavus infection and aflatoxin contamination

Authors
item Shan, Xeuyan -
item WILLIAMS, WILLIAM

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 28, 2014
Publication Date: July 20, 2014
Citation: Shan, X., Williams, W.P. 2014. Toward elucidation of genetic and functional genetic mechanisms in corn host resistance to Aspergillus flavus infection and aflatoxin contamination. Frontiers in Microbiology. 5:364. doi:10.3389/fmicb.2014/00364.

Interpretive Summary: Aflatoxins are carcinogenic mycotoxins produced by the fungus Aspergillus flavus. Aflatoxin contamination of pre-harvest corn occurs when heat and drought conditions favor A. flavus colonization of the developing ears of corn and the subsequent accumulation of aflatoxin. Commercial corn hybrids are generally susceptible to A. flavus infection. Although plant resistance is widely considered an ideal control strategy for reducing aflatoxin contamination of corn, most commercially available corn hybrids are susceptible to aflatoxin contamination. Corn breeders and geneticists employed by USDA-ARS have invested considerable effort in developing corn germplasm lines with resistance to aflatoxin contamination. Low levels of aflatoxin accumulation have been observed in these germplasm lines. Several studies have provided compelling evidence of the quantitative genetic basis of corn host resistance to aflatoxin contamination. Important findings have been obtained from the identification of quantitative trait loci (QTLs) associated with resistance to aflatoxin contamination and the investigation of candidate resistance genes through transcriptomics methods. Elucidation of molecular mechanisms will provide in-depth understanding on the host-pathogen interactions and facilitate the use of molecular markers in breeding corn hybrids with genetic resistance to aflatoxin contamination. This will reduce producers’ losses to aflatoxin contamination and provide a safer and more secure food supply.

Technical Abstract: Aflatoxins are carcinogenic mycotoxins produced by the fungus Aspergillus flavus. Aflatoxin contamination in pre-harvest corn profusely happens when heat and drought field conditions favor A. flavus colonization. Commercial corn hybrids are generally susceptible to A. flavus infection. An ideal control strategy to inhibit aflatoxin production is through increased corn host resistance. Constant efforts have been made by corn breeders to develop resistant corn genotypes. Significantly low levels of aflatoxin accumulation have been observed in certain resistant corn inbred lines. A number of reports have provided compelling evidence supporting the quantitative trait genetic basis of corn host resistance to aflatoxin contamination. Important findings have been obtained from the identification of quantitative trait loci (QTLs) and the investigation on candidate resistance genes through transcriptomics methods. Elucidation of molecular mechanisms will provide in-depth understanding on the host-pathogen interactions and hence facilitate the breeding of corn host resistance.

Last Modified: 8/19/2014
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