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United States Department of Agriculture

Agricultural Research Service

Research Project: INSECT ECOLOGY AND SUSTAINABLE SYSTEMS FOR INSECT PEST MANAGEMENT IN THE SOUTHEASTERN REGION

Location: Crop Protection and Management Research

Title: Expression analysis of stress-related genes in kernels of different maize (Zea mays L.) inbred lines with different resistance to aflatoxin contamination

Authors
item Jiang, Tingo -
item Zhou, Boru -
item Luo, Meng -
item Abbas, Hamed
item Kemerait, Robert -
item Lee, R -
item Scully, Brian
item Guo, Baozhu

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 14, 2011
Publication Date: June 9, 2011
Citation: Jiang, T., Zhou, B., Luo, M., Abbas, H.K., Kemerait, R., Lee, R.D., Scully, B.T., Guo, B. 2011. Expression analysis of stress-related genes in kernels of different maize (Zea mays L.) inbred lines with different resistance to aflatoxin contamination. Toxins. 3(6):538-550.

Interpretive Summary: The fungal metabolites called aflatoxins are among the most potent naturally occurring carcinogens, and are produced primarily by Aspergillus flavus. Aflatoxin contamination has been a chronic problem associated with corn production in the Southern US. Breeding for resistance is currently considered the most effective means to control aflatoxin production. Genetic studies are making every effort to explaining corn resistance mechanisms within various biochemical pathways based on molecular functionality and gene expression and indicated that resistance of corn kernels to aflatoxin is a multigene-controlled quantitative trait, and is under environmental control. The expression level of 94 stress-related genes was surveyed in 7 corn lines as well as the aflatoxin levels. Based on the relative-expression levels, the 7 corn inbred lines were clustered into two different groups. One group included B73, Lo1016 and Mo17, which had higher levels of aflatoxin contamination and lower levels of overall gene expression. The second group included Tex6, Mp313E, Lo964 and A638, which had lower levels of aflatoxin contamination and higher overall levels of gene expressions. Total 6 cross-talking genes were identified which are highly expressed in group 2 but down-regulated in group 1. The genes studied in this research will aid our understanding of corn-Aspergillus interactions and other abiotic factors and could contribute to the public candidate gene testing pipeline for public use.

Technical Abstract: This research examined the expression patterns of 94 stress-related genes in 7 maize inbred lines with differential expression of resistance to aflatoxin contamination. The objective was to develop a set of genes/probes associated with resistance to A. flavus and/or aflatoxin contamination. We selected 94 genes from previous gene expression studies with adversity resistance to test the differential expression in seven maize lines, A638, B73, Lo964, Lo1016, Mo17, Mp313E, and Tex6, using real-time RT-PCR. Based on the relative-expression levels, the 7 maize inbred lines were clustered into two different groups. One group included B73, Lo1016 and Mo17, which had higher levels of aflatoxin contamination and lower levels of overall gene expression. The second group included Tex6, Mp313E, Lo964 and A638, which had lower levels of aflatoxin contamination and higher overall levels of gene expressions. Total 6 cross-talking genes were identified between two groups which are highly expressed in group 2 but down-regulated in group 1. When further subjected to drought stress, there were more genes up-regulated in Tex6 of the second group, and B73 in the first group, however, has fewer genes up-regulated. The transcript patterns and interactions measured in these experiments indicate that the resistant mechanism is a complicated and interconnected process involving many gene products and transcriptional regulators, as well as various host interactions with environmental factors such as drought and high temperature.

Last Modified: 8/27/2014
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