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Identify genes and proteins that enhance resistance to Aspergillus (A.) flavus infection and aflatoxin accumulation in maize: (1) isolate and determine functions of genes associated with resistance to A. flavus infection and aflatoxin accumulation in maize, (2) compare expression patterns of genes associated with resistance in maize cultivars with varying levels of resistance or susceptibility to A. flavus/aflatoxin, (3) determine abiotic and biotic factors that affect the expression of genes associated with resistance to A. flavus/aflatoxin.
Approach:
Maize cultivars with varying levels of resistance or susceptibility to A. flavus infection and aflatoxin accumulation will be grown in field plots. Developing ears will be inoculated with toxin-producing and non-toxin-producing strains of A. flavus at predetermined times after pollination, and tissue will be collected from both inoculated and non-inoculated ears at various intervals throughout the growing season. Plants will be monitored for response to drought and heat stress. Maize and fungal proteins, RNA, and DNA will be extracted from tissue samples. Expression profiles of different tissues collected at various times from resistant and susceptible maize genotypes grown under different conditions will be compared using electrophoresis, microarrays, micro-RNA, and other appropriate proteomic or genomic techniques. Genes and proteins identified in these studies will be developed as molecular markers for enhancing resistance to aflatoxin accumulation in maize hybrids.