To ensure their survival in the natural world, plants must recognize and respond to a wide variety of insect herbivores. Among these attackers, aphids and other hemipteran insects pose a particular challenge because they insert their slender stylets intercellularly to feed from the phloem sieve elements, thereby causing relatively little overt tissue damage. Specific plant recognition pathways are required for initiating resistance or tolerance to this unique insect feeding style. The genetic model plant Arabidopsis thaliana (mouse-ear cress), in combination with the well-studied and ubiquitous aphid, Myzus persicae (green peach aphid), provides an excellent system for studying plant responses to phloem-feeding insects. Plant bioassays with fractionated aphid saliva will identify salivary components that induce plant defense responses. The resulting gene expression changes, as well as changes in plant primary and secondary metabolism will be investigated. A broader impact of the proposed research is that the discovery of as yet unknown elicitors released by phloem feeding insects and the resulting metabolic responses in the host plants will lead to improved agricultural pest management strategies. In addition, the project will contribute to the education of a new generation of chemical ecologists and plant molecular biologists. Summer interns participating in this project will be recruited through a well-established undergraduate plant research program that is organized by the principal investigator.
