Abstract

Jake C. Fountain, Zhi-Yuan Chen, Brian T. Scully, Robert C. Kemerait, R. DeweyLee, Baozhu Guo

Aflatoxins are carcinogenic compounds produced by Aspergillus flavus during infection of crops including maize (Zea mays L.). Contamination of maize with aflatoxin is exacerbated by late season drought stress. Previous studies have implicated numerous resistance-associated proteins (RAPs) that may be responsible for resistance to A. flavus colonization and aflatoxin accumulation. This study examined the transcript levels of three genes encoding RAPs utilizing quantitative real-time PCR, ZmPR -10 (PR-10), glyoxalase I (GLX-I), and a 14-kDa trypsin inhibitor (TI-14), in different maize lines under drought stressed and irrigated conditions to determine their potential utility as molecular markers for germplasm. Results suggested that drought stress during kernel development affected gene expression differently in different genotypes. Results showed that physiological stress induced by drought conditions was insufficient to stimulate significant changes in the expression of genes coding for the pathogen-specific, pathogenesis-related proteins PR-10 and GLX-I. However, ti-14 transcript levels were found to be elevated significantly indicating its possible use as a selection marker.