| Summary: | 碩士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 99 === Tung oil is an important feedstock of lubricant and polishes and consisted of special unusual conjugated fatty acid, eleostearic acid. Vernicia fordii (Vf) and
Vernicia montana (Vm) are popular species for oil industry in America and Asia but less discussed on the oil biosynthesis of these trees. My thesis figured out the genetic and physiological difference between Vf and Vm and proposed the crucial factors of quantity and quality of tung oil. The oil amount in the developing seed of Vf is equal to that of Vm , but oil amount in matured seed of Vf is 1.6 fold than that of Vm. Several oil-related genes, such as fatty acid desaturase (FAD) and diacylglycerol transferase (DGAT), displayed higher homology in amino acid sequence and shared the copy number in the genomes between two tung trees. It revealed that the difference of oil character between two tung trees was not caused by the gene function itself. Furthermore, the expression level of FAD3 in developing seed of Vf is higher than in Vm, but that of FADX is in the reverse in Vm. The expression pattern of oil-related genes was not consistent with the fatty acid composition of two tung trees and brought out the complex regulatory network in the oil biosynthesis between two tung trees. The oil-related genes of Vf were elevated under higher ambient temperature condition but not in Vm. Moreover, expression level of oil-related genes in Vf and Vm were not influenced by phytohormones excluding jasmonic acid.
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