The flowers of many plants synthesize and emit scent as a means of attracting pollinators, and low seed/fruit set could result if the plant is not successful in the competition for the attention of locally available pollinators. Benzenoid esters, including methylsalicylate, are among the most common, and most efficacious, scent volatiles that flowers emit to attract moths and other insect pollinators. Yet, until the recent work from the lab of the principle investigator, little had been known about how plants synthesize them. In this project, Dr. Pichersky's lab will continue the biochemical and structural characterization of two benzenoid ester-forming enzymes that his lab recently identified, including the enzyme that catalyzes the formation of methylsalicylate. They will also identify and characterize a key enzyme that acts at an earlier step in the pathway and that is responsible for the shortening of the carbon skeleton of the benzoic acid precursor from C9 to C7. In addition to the biochemical characterization of these enzymes, they will determine their cellular and subcellular localization and the mode of regulation of the genes encoding them. This project should result in a substantial enhancement of the understanding of this important plant biochemical pathway, and the isolation of the genes could eventually lead to the ability to manipulate floral volatiles in agronomically important crops to enhance visitation frequencies by insect pollinators and thereby increase fruit/seed yields.
