Dissertation
REGULATION OF TERPENOID BIOSYNTHESIS IN SECRETORY CELL TYPES
Doctor of Philosophy (PhD), Washington State University
01/2018
Handle:
https://hdl.handle.net/2376/108998
Abstract
Secretory cells are modified epithelial cells that are highly specialized in the biosynthesis, storage, and secretion of specialized (or secondary) metabolites that provide the plant with a boundary against biotic and abiotic threats. These cells are generally non-photosynthetic, rely on oligosaccharide import from neighboring cells, and exhibit unordinary expression of genes involved in specialized metabolic pathways. Here, we describe the metabolic functionalities and the governing processes in the secretory cell types known as glandular trichomes (GTs) and resin ducts. GTs cover the leaf and stem surfaces of ~30% of all vascular plants, however there is fossil evidence suggesting that they first appeared on seed fern leaves at least 290 million years ago. GTs synthesize and store multiple classes of secondary metabolites (terpenoids, phenylpropanoids, flavonoids, methyl ketones, acyl sugars, etc.) depending on the plant species of interest. Resin ducts, on the other hand, are commonly found in conifer species of the genera Pinus, Picea, Larix, and Psudotsuga, and accumulate oleoresins composed of mixtures of liquid volatiles (primarily monoterpene olefins), and dissolved solids (primarily diterpenoids). The resin duct system of conifers is composed of two lateral ducts on opposite sides of the needles and are surrounded by the tissue of the central vascular cylinder, where it is hypothesized that oligosaccharides are imported into the resin duct for specialized metabolite production. The past decades have witnessed tremendous progress regarding the elucidation of the biochemical pathways involved in secretory structures, however how these specialized pathways are regulated remain to be extensively studied. Using a combination of chemical analyses, molecular biology, genomic sequencing technologies, and computational biological approaches we have shed light on how specialized metabolic pathways within secretory cell types are regulated, how global metabolism in these unique cell types is carried out, and how genetic mutations and global gene expression patterns influence secretory cell chemistry. Additionally, we report the characterization of two terpene synthase (TPS) enzymes specific to the glandular trichomes of Cannabis sativa.
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Details
- Title
- REGULATION OF TERPENOID BIOSYNTHESIS IN SECRETORY CELL TYPES
- Creators
- Jordan James Zager
- Contributors
- B. Markus Lange (Advisor)Hans-Henning Kunz (Committee Member)Karen Sanguinet (Committee Member)John Browse (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Molecular Plant Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 185
- Identifiers
- 99900581818401842
- Language
- English
- Resource Type
- Dissertation