The involvement of a PIG3 homolog quinone oxidoreductase gene in maize resistance to insects and fungi demonstrated through transgenic expression in maize callus

Insect and pathogen damage of maize inhibits sustainable production. Discovery of maize genes coding for products active against both classes of pests would significantly accelerate the rate of development of resistant varieties. A quinone oxidoreductase gene homologous to apoptosis related P53 inducible gene 3 (PIG3) in vertebrates was identified as a pest resistance candidate in a quantitative trait locus region for maize ear rot resistance. The quinone oxidoreductase gene was cloned from a Fusarium resistant inbred of maize and expressed in maize callus. The transformed callus had some significant resistance to the maize pathogen F. graminearum, compared to control transformants, and was often highly resistant to two major caterpillar pests of maize. A band of enhanced reactive oxygen species (ROS) generation in the presence of relevant substrates was noted when protein extracts from the transgenic callus compared to those from control callus were separated by polyacrylamide gel electrophoresis. Thus, presence or introduction of an optimally functional form of this gene should lead to enhanced resistance of maize and other crops to major insect and fungal pests.