A major constraint of seed production worldwide is contamination of a large number of crops with fungi that produce toxic, teratogenic and carcinogenic mycotoxins. Accumulating evidence suggests that a subset of small molecules called oxylipins (oxygenated fatty acids produced by conserved oxygenases) are important in the seed/fungal/mycotoxin interaction. Recent data suggests that maize 9-lipoxygenase-derived oxylipins play a pivotal role in spore and mycotoxin production by the mycotoxin producing genera Aspergillus and Fusarium. These data prompted a hypothesis that 9-lipoxygenase (LOX) derivatives are susceptibility factors in plants that act as signals to increase fungal sporulation and mycotoxin production in maize. The central hypothesis that will be tested by this study is that A. flavus and maize induce, intercept and recognize each others oxylipins which in turn directs the outcome of the maize/fungal/mycotoxin interaction. This will be accomplished: (1) by disrupting all 9-LOX genes in corn lines that contrast in the level of resistance to aflatoxin accumulation; (2) by disrupting oxylipin-producing oxygenases in A. flavus; and (3) by elucidating the requirement of oxylipins in the Aspergillus/maize interaction using maize and fungal mutants. This study is expected to generate conclusive evidence of cross kingdom lipid-based signaling communication that governs the outcomes of plant-pathogen interactions. These results will be of great significance to a larger scientific community involved in the studies of cross-talk signaling not only in plant-pathogen but also in animal- and human-pathogen interactions. The broader impacts of this proposal could result in production of mycotoxin resistance incorporated into commercial lines that is of great and immediate significance for the general public, seed industry, maize growers and breeders. Furthermore this proposal will result in training and education of graduate students and postdoctoral fellows in cross-disciplinary fields of plant and fungal genetics, molecular biology and biochemistry and mentoring of undergraduates in laboratory and class settings.
