Dissertation
INVESTIGATING THE BIOSYNTHESIS, FUNCTION AND PHYSIOLOGICAL SIGNIFICANCE OF ISOPRENOIDS IN ARABIDOPSIS THALIANA
Doctor of Philosophy (PhD), Washington State University
01/2016
Handle:
https://hdl.handle.net/2376/112002
Abstract
Isoprenoids are a class of secondary metabolites comprising approximately 50,000 compounds in land plants with enormous structural and functional diversity. The physiological functions of isoprenoids range from hormone-mediated growth regulation to structural components of lipid bilayers. The involvement of isoprenoid-derived hormones in plant development is well-established, but in many cases the signal transduction pathways involved in growth regulation are poorly understood. Here, we report the characterization of two transcription factors, bHLH093 and bHLH061, that are involved in the coordination of gibberellic acid-dependent shoot growth and the maintenance of meristem activity in Arabidopsis thaliana (L.). Sterols, a class of triterpene derivatives, are important structural components of the plasma membrane in eukaryotes. In plants, sterol biosynthesis is required to produce the precursors for brassinosteroids biosynthesis, and changes in sterol levels and composition have also been implicated in response to cold and heat stress. Furthermore, sterols are required for maintaining the structure of detergent-resistant microdomains within the plasma membrane. These microdomains are enriched in sterols and sphingolipids and serve as docking sites for specific proteins involved in signaling, hormone transport, and cellulose production. Recent studies point towards a coordination between sphingolipid and sterol biosynthesis and have outlined the importance of HMG-CoA reductase in controlling sterol biosynthesis in plants. Here we evaluate the effects of HMGR overexpression on sterol biosynthesis across different tissues of Arabidopsis thaliana and identify downstream rate-limiting steps in sterol biosynthesis. We also report the first characterization of a Niemann-Pick disease type C1 (NPC1)-like protein in Arabidopsis, the mammalian ortholog of which is implicated in the trafficking of sterols and sphingolipids.
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Details
- Title
- INVESTIGATING THE BIOSYNTHESIS, FUNCTION AND PHYSIOLOGICAL SIGNIFICANCE OF ISOPRENOIDS IN ARABIDOPSIS THALIANA
- Creators
- Brenton Cole Poirier
- Contributors
- Bernd M Lange (Advisor)John A Browse (Committee Member)Asaph B Cousins (Committee Member)John K Fellman (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Molecular Biosciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 144
- Identifiers
- 99900581432801842
- Language
- English
- Resource Type
- Dissertation