Dissertation
OILSEED ENGINEERING AS A MEANS TO UNDERSTAND FATTY ACID MODIFICATION, LIPID SYNTHESIS, AND REGULATION IN MODEL OILSEED CROPS
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000002432
Handle:
https://hdl.handle.net/2376/121166
Abstract
Lipids play an essential role in all forms of life by forming the structural components of cellular membranes. In plants, lipids are energy storage molecules in the seed in addition to the roles they have in signaling, plant defense, wax-ester biosynthesis and membrane formation. Plant seed oil is composed of Triacylglycerol and is used as vegetable oil. This has led to a wide body of work studying fatty acid and lipid biosynthesis and modification. The work present here investigates several aspects of lipid biochemistry starting with the role Phospholipases and Long Chain Acyl-CoA Synthetases (LACS) enzymes in the accumulation of hydroxy fatty acids (HFAs), in the model organism Arabidopsis thaliana. A major bottle neck in the production of HFAs has been their accumulation on phosphatidylcholine (PC), the membrane lipid on which they are produced resulting in low HFA accumulation and reduce seed oil. Past work showed that expression of an HFA specific Phospholipase A2α liberates HFAs from PC, but decreases HFA content in the oil, potentially due to deficient LACS enzymes specific to HFAs. I demonstrated that LACS activity towards HFAs is not deficient in these plant lines. Understanding oilseed engineering in Arabidopsis has also led to many advances in modifying fatty acid composition. Reducing saturated fatty acid content of seed oil results in oil with superior qualities for food and fuel. To that end I expressed to ∆9 desaturases in the oil seed crop plant Camelina sativa. Expression of FAT5, a C. elegans palmitoyl-CoA desaturase and a DES9*, an engineered glycerolipid desaturase, significantly reduced the saturated fatty acid content of Camelina seed oil without compromising plant growth and development. Given the importance of lipids to plant biology their biosynthesis is well regulated. I identified a regulator of the first step of lipid synthesis in both leaf and seed tissue, which appears to have an important role in both plant development and the fatty acid proportion of seed oil.
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Details
- Title
- OILSEED ENGINEERING AS A MEANS TO UNDERSTAND FATTY ACID MODIFICATION, LIPID SYNTHESIS, AND REGULATION IN MODEL OILSEED CROPS
- Creators
- Jesse D Bengtsson
- Contributors
- John A Browse (Advisor)Lisa M Gloss (Committee Member)Sanja Roje (Committee Member)Bernd Markus Lange (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Molecular Plant Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 206
- Identifiers
- 99900606757001842
- Language
- English
- Resource Type
- Dissertation