Abstract: Methods for identifying ligands of G-protein coupled receptors are provided. Methods generally involve the steps of associating a GPCR having a functional conformation with a support, interacting a naturally-derived sample with the GPCR to bind a molecule in the sample to the GPCR and separating the molecule from the support.

Abstract: The present invention provides methods and materials that enhance a plant's resistance to certain pathogens. A novel pathway is described and has been designated with the acronym, SI-SAR pathway, for salicylic acid-independent systemic acquired resistance. DNA constructs and methodologies are provided that facilitate the identification of compounds that activate this pathway. Methods are provided to enable the identification of novel genes and signaling components that are expressed when the SI-SAR pathway is activated. Transgenic plants with altered expression of these novel genes or signaling components of the pathway are expected to have enhanced resistance to plant pathogens. Also provided is a novel, pathogen-induced epoxide hydrolase that is inducible in the absence of SA.