Date of Award

5-2016

Degree Type

Honors College Thesis

Department

Chemistry and Biochemistry

First Advisor

Philip Bates, Ph.D.

Advisor Department

Chemistry and Biochemistry

Abstract

The demand for plant oils is increasing exponentially, which poses a problem as the resources required to produce plant oils are limited. In an effort to alleviate this problem, transgenic tobacco plants that are producing TAG yields of 15% by weight in non-seed tissues have been engineered (Vanhercke et al. 2014). In order to achieve even higher oil yields, the pathway that contributes to TAG synthesis in the leaves of these plants needed to be determined. There are three potential pathways that could contribute to TAG synthesis. In order to determine which of these was the major contributor, metabolic tracing was used to measure the flux of intermediates through TAG metabolism.

[14C]acetate was used to trace lipid metabolism in developing “wild type” and “high oil” plants. This radiolabeled acetate incorporated into TAG metabolism via fatty acid synthesis, labeling newly synthesized fatty acids with [14C]. The results of this experiment revealed that in twild type tissue, fatty acids fluxed through intermediates and primarily ended up in MGDGs, but in high oil tissue, fatty acids fluxed through PCs before incorporating into TAGs. Incorporation of radiolabel into PCs at early time points suggested that fatty acids participate in acyl editing before being esterified to precursors in the synthesis of TAGs. This revealed that leaf oil and membrane lipid synthesis are overlapping biosynthetic pathways. In future experiments, [14C]glycerol tracing will be conducted to further elucidate the pathway contributing to TAG synthesis in the leaves of transgenic tobacco plants.

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