Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/21/2007
Publication Date: 6/18/2007
Citation: Luo, M., Liu, J., Lee, R.D., Guo, B. 2007. Expression of defense-related genes in maize developing kernels in late stages [abstract]. Proceedings of the American Phytopathological Society Meeting, July 28 - August 1, 2007, San Diego, CA. Interpretive Summary:
Technical Abstract: We analyzed temporal patterns of gene expression profiles in developing kernels of Tex6, reported to have reduced aflatoxin contamination, at 25, 30, 35, 40 and 45 days after pollination (DAP) using maize oligonuleotide microarray. There was a total of 57,452 70-mer oligonucleotides on the array. The objective was to study the defense-related genes in developing kernels of Tex6 at the time favorable for aflatoxin contamination. A total of 8497 positive array spots were detected with unique IDs and 4247 cross-talking genes were identified in all sampling stages. The trends of total numbers of expressed genes, genes with known function, and specific genes in different stages were decreasing when kernels were maturing during these late developing stages. However, levels and patterns of gene expression were different. Expression patterns of key genes in several metabolic pathways, including starch, lipid and storage proteins, were analyzed. Significant expression of 823 defense-related genes was identified. In comparison with 25 DAP, expression of 351 genes was significantly different at 45 DAP (P < 0.05), and 211 genes were up-regulated. Overall, 83% of these genes were expressed as up-regulated or unchanged even after 40 DAP. The expression of defense related genes was significant and important in Tex6 late developing kernels in order to protect the kernels from the stresses. At genetic expression level, the defense genes could be expressed differently in different corn genotypes that could explain the observed differences in aflatoxin contamination in corn kernels.