Submitted to: Aflatoxin Elimination Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 2003
Publication Date: December 15, 2003
Citation: Guo, B., Liang, X.Q., Luo, M., Dang, P.M., Holbrook Jr, C.C. 2003. Molecular characterization of resistant mechanisms to aflatoxin contamination and generation of ests and microarray chips for analysis of gene expression in peanut [abstract]. In: Proceedings of the 3rd Fungal Genomics, 4th Fumonisin, and 16th Aflatoxin Elimination Workshops, October 13-15, 2003, Savannah, Georgia. p. 8. Technical Abstract: Cultivated peanut exhibits a considerable amount of variability for morphological traits and for resistance to insects and diseases. However, previous research with molecular markers has detected little variation at the DNA level. Gene discovery and marker development are needed in cultivated peanut. The development of new technology using EST (expressed sequence tag) and EST-derived SSR (simple sequence repeat) should enable research to finally measure and exploit variation at the DNA level in the cultivated peanut species. We have generated about 2000 ESTs from two cDNA libraries of peanut, immature pods of A13 (tolerate to drought stress and preharvest aflatoxin contamination) and leaf tissues of peanut line C34-24 (resistant to leaf spots and tomato spotted wilt virus). This was the first report on peanut EST generation and functional genomics, and 1345 ESTs have been released to GenBank (CD037499 to CD038843) and produced microarray chips for gene expression analysis. We have successfully used these ESTs for gene identification and EST-derived SSR marker development. In the laboratory screening of the germplasm from China and India, the differences of peanut kernel infection by A. flavus were significant. Several Chinese and Indian lines had lower A. flavus colonization than Georgia Green. Evidence supports that trypsin inhibitor is associated with the resistance in the laboratory, and the concentration and activity of TI in resistant genotypes were higher than in susceptible genotypes. The induction of chitinase and ß-1-3-glucanase by infection were evidenced in resistant more than in susceptible genotypes. The roles of chitinase and ß-1-3-glucanase were possible in association with the resistance/susceptibility to aflatoxin formation in peanut and are needed for further investigation.