Thesis
ELUCIDATING THE ROLE OF TRIACYLGLYCEROL LIPASE SUGAR-DEPENDENT PROTEIN 1 (SDP1) ON REDUCED SEED OIL ACCUMULATION AND MEDIUM CHAIN FATTY ACIDS LEVELS IN TRANSGENIC CAMELINA SATIVA
Master of Science (MS), Washington State University
2025
Abstract
The global demand for sustainable aviation fuels (SAFs) is rising, but current feedstocks are limited. Medium-chain fatty acids (MCFAs; C8–C14) are attractive for SAF production because of their favorable combustion properties, yet natural sources such as coconut, palm kernel, and Cuphea species suffer from poor agronomic traits or restricted cultivation regions. Temperate oilseeds like Camelina sativa have therefore emerged as promising bioengineering platforms for MCFA production. However, previous efforts to express heterologous thioesterases and acyltransferases in Camelina introduced MCFAs at the expense of total oil yield, suggesting bottlenecks involving substrate specificity, precursor supply, and triacylglycerol (TAG) turnover by lipases such as SUGAR-DEPENDENT1 (SDP1).This study tested whether TAG turnover by SDP1 constrains MCFA accumulation. Two engineered Camelina lines were analyzed: the C10 line expressing CvFatB1, CnLPAAT, and CpuDGAT1, and the C12 line expressing UcFatB and CnLPAAT. Seed-specific suppression of CsSDP1 by RNAi increased oil yield across wild-type and engineered lines without impairing germination. In the C10 background, SDP1 suppression stabilized 10:0 retention and partially restored oil yield, indicating that SDP1 hydrolyzes 10:0-rich TAGs. In contrast, suppression in the C12 background reduced 12:0 levels while increasing polyunsaturated fatty acids, revealing a role for SDP1 in TAG remodeling needed for efficient laurate incorporation at sn-1/3 positions. Positional analysis confirmed that SDP1 acts selectively on unusual FA- and PUFA-containing TAGs.
Overall, SDP1 suppression improved seed size and oil yield but had divergent effects on MCFA composition. These results highlight the dual degradative and remodeling roles of TAG lipases and the need for coordinated engineering of lipases and acyltransferases to optimize MCFA accumulation in Camelina for SAF production.
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- Title
- ELUCIDATING THE ROLE OF TRIACYLGLYCEROL LIPASE SUGAR-DEPENDENT PROTEIN 1 (SDP1) ON REDUCED SEED OIL ACCUMULATION AND MEDIUM CHAIN FATTY ACIDS LEVELS IN TRANSGENIC CAMELINA SATIVA
- Creators
- Agasthya Baby chenna Chenna Prakash
- Contributors
- Philip D Bates (Advisor)Laura Bartely (Committee Member)Helmut Kirchhoff (Committee Member)Andrei Smertenko (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Molecular Plant Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Number of pages
- 74
- Identifiers
- 99901357898401842
- Language
- English
- Resource Type
- Thesis