Enhanced insect and fungal resistance of maize callus transgenically expressing a maize E2F regulatory gene

A maize gene coding for an E2F regulatory protein located in a quantitative trait locus (QTL) for Fusarium ear rot resistance was cloned and transgenically introduced into maize callus. Several of the transformants were more resistant to feeding by corn earworms and fall armyworms, and retarded growth of Fusarium proliferatum compared to GUS control transformants. More effective transformants contained higher levels of E2F product than GUS controls as indicated by antibody detection. Increased and decreased levels of regulated proteins were noted in E2F overexpressing compared to GUS expressing control transformants. These differentially produced proteins were previously reported to be interactors with the E2F protein, suggesting E2F is affecting the production of these proteins. Other proteins coded for by genes reported to interact with the relevant E2F protein and associated phenotypic effects that could be promoting resistance include those that would increase cell resistance to water stress, increase the presence of reactive oxygen species, and increase the density of indigestible components. Although the full complex of responsible proteins regulated by the E2F examined that promote resistance to insects and fungi remains to be determined, overproduction of the E2F in transgenic callus enhances resistance to some maize insect and fungal pests.