請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/48774
標題: | 三年桐與千年桐油脂生合成基因之分子特性 Molecular Characterization of Oil-biosynthetic genes in Vernicia fordii and Vernicia montana |
作者: | Du-Jhen Lin 林渡真 |
指導教授: | 王亞男,葉開溫 |
關鍵字: | 三年桐,千年桐,油脂生合成基因,桐油酸,脂肪酸去飽和酶, Vernicia fordii,Vernicia montana,Oil-biosynthetic genes,Eleostearic acid,Fatty acid desaturase, |
出版年 : | 2010 |
學位: | 碩士 |
摘要: | 目前各國皆積極發展植物性油脂做為生質柴油,但植物性油脂具有較高之黏性與冷濾點(Cold filter plugging point,CFPP)等缺點不適合完全做為車用燃料,仍需與石化柴油混合使用。油脂性質是由於其脂肪酸成分與比例造成,植物常藉由改變脂肪酸比例來適應外在環境之變化,本論文以千年桐與三年桐做為材料,從分子生物層面探討木本植物種子油脂生合成與環境因子之影響。
首先分析兩種油桐不同發育階段之果實與葉片及成熟種子之油量與脂肪酸組成發現三年桐種子含油率較千年桐多10%,三年桐果實中脂含油量在成熟後期大約為千年桐之1.6 倍,成熟種子主要脂肪酸成分為棕梠酸、硬脂酸、油酸、亞麻油酸、桐油酸,在果實及葉子中雖沒有偵測到桐油酸,但却含有大量C18:3 的次亞麻油酸。再者擴增出三年桐與千年桐相關油脂生合成基因包括酯化的DGAT2與延長碳鏈的FAE1 不飽和酶系統的SAD、FAD2、FAD3、FADX,與還原系統的Cytochrome b5 和Cytochrome b5 reductase。比對兩種油桐各基因胺基酸序列,結果發現序列在兩種植物中相似度非常高,且其基因套數也雷同,因此認為兩油桐之油量與油性差異並非基因型(genotype)有異造成。比較不同發育階段的果實各基因的表現情形,發現大多數基因的表現並無明顯地差異,只有決定桐油酸�次亞麻油酸比例的FADX 與FAD3 在兩種油桐却有顯著的差異。三年桐之FAD3基因表現量隨果實發育增加,但FADX 在果實發育階段則偵測不到其表現,千年桐之FAD3 在果實發育過程其基因表現量維持一定,FADX 在直徑六公分時開始偵測到有表現,脂肪酸分析試驗也僅在成熟種子中偵測到桐油酸。因此決定油桐種子脂肪酸成分是在果實成熟後至種子成熟這段期間之基因表現差異所造成。在不同環境處理下發現,溫度為調控脂肪酸相關基因主要因子。三年桐中脂肪酸相關基因能受較高的環境溫度誘導而增加表現量,反之千年桐則否。此外也分析植物荷爾蒙對於油桐脂肪酸合成基因的影響,除了茉莉酸(Jasmonic acid)可同時誘導兩種油桐的FAD3 表現,大多數的植物賀爾蒙階對兩種油桐的脂肪酸相關基因無明顯的誘導作用。 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. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/48774 |
全文授權: | 有償授權 |
顯示於系所單位: | 森林環境暨資源學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-99-1.pdf 目前未授權公開取用 | 7.3 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。