A microarray-based approach for identifying genes for resistance to Fusarium Graminearum in maize ( Zea Mays L.)

Fusarium graminearum causes gibberella ear rot in maize. The incidence and severity of the disease is strongly influenced by environmental factors and can reach epidemic levels. The infection can result in severe reduction in crop quality because of contamination of the grain with trichothecene mycotoxins. The best strategy for control of the disease is to develop resistant hybrids. Unfortunately, most commercial maize hybrids currently grown in Canada have little or no resistance to infection by Fusarium graminearum . In a previous study, we identified several Quantitative Trait Loci (QTL) for resistance to gibberella ear rot in maize. The focus of this work was to identify genes underlying those QTLs by using microarray-based Comparative Genomic Hybridization (CGH). The 46K maize 70-mer oligo microarray (University of Arizona) was hybridized with the Alu I digested genomic DNA from CO387 (resistant) and CG62 (susceptible) parental lines and with the pooled resistant and susceptible recombinant inbred lines from the CG62 × CO387 population. Approximately one hundred of genes (t-test) had significant hybridization intensity differences between resistant and susceptible parents and pools. Some of these genes (chitinase, protein kinase) were similar to previous gene-based markers that were identified to cosegregate with Fusarium resistance QTLs. The identified resistance genes will be converted into markers that can easily be scored to allow rapid introgression of gibberella ear rot resistance into elite germplasm