Collaborative Research: Signals, genes, and metabolites in defense priming mediated by maize 12-oxo-phytodienoate reductases in maize.
Green leafy volatiles (GLVs), the odor typically associated with wounded or cut plants, are potent signaling molecules involved in the regulation of plant defense against insect herbivores and pathogens. In addition to activating direct responses, GLV exposure also prepares (or primes) even non-infested plants for subsequent attack by pests and pathogens by allowing the plant to respond faster and stronger to the actual infestation. Among the genes up-regulated in maize in response to GLVs exposure were several members of the 12-oxo-phytodienoate reductase (OPR) gene family. This was accompanied by an increase in total OPR enzyme activity at the time of priming. OPRs seem to play a significant role not only in the regulation of the octadecanoid signaling pathway with jasmonates as its end-product, but also in the regulation of other important defense signals. The goal of this project is therefore to comprehensively analyze the biochemical and physiological roles of six maize OPR family members in the priming of defense responses to insect herbivores and pathogens and in the regulation of direct defenses. The PIs will analyze this class of proteins biochemically, molecularly, and genetically by using transposon-insertional OPR mutants of maize and by testing the recombinant OPR proteins in vitro. Defense priming to insect herbivory and diseases is an emerging exciting but little understood area in plant biology. This project aims to provide basic knowledge about potential molecular and biochemical mechanisms of priming and will eventually help to develop environmentally sound pest and pathogen management strategies. The results of this project will be broadly disseminated through publications, incorporation into textbooks and coursework, and press releases to local newspapers and web-based journals. The project is multidisciplinary in nature and will provide participating students with a truly integrative experience by combining such diverse areas as molecular biology, biochemistry, entomology, plant pathology, chemical ecology and many more.
