ME: Metabolic Engineering to Study the Regulation/Plasticity of and to Modify Diterpene Metabolism in Trichome Gland Cells

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

This project exploits the plant trichome (leaf hair) gland, a specialized plant tissue that produces and exudes copious end-product secondary biochemicals that are involved in pest and disease resistance. This aggregate of cells suspended on a stalk above leaf and stem surfaces produces massive exudates that have species-specific, simple diterpene chemical profiles. Dr. Wagner will study metabolic regulation that controls carbon flow in glands into specific diterpenes by introducing genes that encode enzymes which have potential to divert carbon flow into non-endogenous but closely related diterpenes. Gene suppression experiments will also be used to metabolically engineer endogenous diterpene metabolism and study the plasticity of diterpene biosynthesis in glands. These efforts will be based on a well characterized gland system, available genes from this system, and the recent demonstration of diterpene metabolic engineering in this system using a gene suppression approach. In addition to being a system amenable to studying metabolic regulation of diterpene metabolism, plant trichome glands that produce copious diterpenes have potential to serve as "factories" for renewable and efficient production of pharmaceutically active diterpenes that are currently available only from environmentally-sensitive sources (e.g., those from soft corals). An understanding of the metabolic regulation and plasticity of diterpene metabolism in trichome gland cells is needed if this high production cell type is to realize its potential as a renewable resource for producing valuable diterpenes and other secondary metabolites. In addition, a better understanding of secondary metabolism in trichome glands can also aid in efforts to increase natural disease resistance in crop plants. Trichome gland-based resistance of primitive tomato, potato, and other plants has often been lost during breeding of cultivated varieties to optimize yield, etc. These properties might be re-established through metabolic engineering of trichome glands. Broader aspects of the project include training and learning at the postdoctoral, graduate, undergraduate and technician levels. Under-represented groups will be included in the project. The project will enhance the infrastructure of research and education by developing the diterpene trichome gland system as a tool for studying metabolic regulation and engineering, and establishing a partnership between G. Wagner's terrestrial plant biology laboratory and W. Fenical's (collaborator) marine animal biology laboratory, both having a common interest in diterpene metabolism. A second, broader impact is the potential for the project to produce information that can be disseminated through commercial channels to provide new opportunities for sustainable agriculture. Our long term goal is to develop the trichome gland system as a renewable, economical system for producing terpenes and other products, including pharmacologically active marine diterpenes.