Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2001
Publication Date: 10/1/2002
Citation: CHEN, Z.Y., BROWN, R.L., DAMANN, K.E., CLEVELAND, T.E. IDENTIFICATION OF MAIZE KERNEL EMBRYO PROTEINS ASSOCIATED WITH RESISTANCE TO AFLATOXIN CONTAMINATION THROUGH PROTEOME ANALYSIS. PHYTOPATHOLOGY. 2002. V. 92. P. 1084-1094. Interpretive Summary: Aflatoxins are poisons produced by the fungus Aspergillus flavus after it infects agricultural commodities such as corn. Contamination of corn with aflatoxins causes financial loss to growers and is a potential health hazard to animals and humans. Corn kernel proteins have been shown to play a role in resistance against aflatoxin contamination. Using state-of-the-art protein separation techniques to compare resistant corn lines to susceptible ones, proteins associated with resistance have been identified. Some of these proteins are related to the plant's ability to adapt to water-stress. Their identification may signal a breakthrough in understanding natural resistance to aflatoxin contamination. Genes for these proteins can then be identified and transferred to more commercially-acceptable corn lines through breeding. This could result in development of resistant corn lines in a shorter time period and the control of aflatoxin contamination, which would, in turn, result in increased financial savings to growers, and enhanced protection to the public.
Technical Abstract: Aflatoxins are carcinogens produced by Aspergillus flavus and A. parasiticus during infection of susceptible crops such as maize and cottonseed. Though resistant maize genotypes have been identified, the incorporation of resistance into commercial lines has been slow due to the lack of selectable markers. Here we report the identification of potential lmarkers associated with resistance in maize using a proteomics approach. Kernel embryo proteins from two resistant and several susceptible genotypes have been compared using large format 2-D gel electrophoresis. Preliminary comparisons of reproducibly detected embryo protein spots have found both quantitative and qualitative differences between resistant and susceptible genotypes. Several spots with major qualitative or quantitative differences have been sequenced using ESI- MS/MS and Edman degradation after trypsin digestion. Based on peptide sequence homology analysis, these potential resistance markers belong to the following categories: storage proteins (globulin 1 and globulin 2), late embryogenesis abundant proteins that are related to drought or desiccation (LEA3 and LEA14), water- or osmo-stress related proteins (WSI18, aldose reductase), and heat stress related proteins (HSP16.9). The significance of these proteins in host resistance against fungal infection and drought tolerance are also discussed.