In order to better understand the mechanism of defense gene induction in maize in responseto A. flavus infection, particularlythe role of WRKY transcription factors, we examined the findings of a recent series of microarray analyses by Luo et al. [26] of a resistant and a susceptible maize line derived froma cross between 1638 and GT-MAS:gk, Eyl25 and Eyl31, respectively [27], to identify WRKY transcription factors differentially regulated between the two lines. We selected several candidate WRKY genes based on the above microarray study and examined their expression in the resistant TZAR101 and susceptible B73 maize lines over a time course of infection in Louisiana field conditions using qPCR. In addition, the expression levels of several indicator genes, NPR1 and PR-1, which regulate SA-based defenses [28], and ethylene responsive factor 1 (ERF1), which regulates JA and ethylene-based defenses [29], were also examined in order to determine which major phytohormone defense pathways were regulated by A. flavus infection.