Cahoon Edgar B, Dietrich Charles R, Meyer Knut, Damude Howard G, Dyer John M, Kinney Anthony J
USDA-ARS Plant Genetics Research Unit, Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA.
Phytochemistry. 2006 Jun;67(12):1166-76. doi: 10.1016/j.phytochem.2006.04.013. Epub 2006 Jun 9.
Expression of Delta(12)-oleic acid desaturase-related fatty acid conjugases from Calendula officinalis, Momordica charantia, and Vernicia fordii in seeds of soybean (Glycine max) or an Arabidopsis thaliana fad3/fae1 mutant was accompanied by the accumulation of the conjugated fatty acids calendic acid or alpha-eleostearic acid to amounts as high as 20% of the total fatty acids. Conjugated fatty acids, which are synthesized from phosphatidylcholine (PC)-linked substrates, accumulated in PC and phosphatidylethanolamine, and relative amounts of these fatty acids were higher in PC than in triacylglycerol (TAG) in the transgenic seeds. The highest relative amounts of conjugated fatty acids were detected in PC from seeds of soybean and A. thaliana that expressed the C. officinalis and M. charantia conjugases, where they accounted for nearly 25% of the fatty acids of this lipid class. In these seeds, >85% of the conjugated fatty acids in PC were detected in the sn-2 position, and these fatty acids were also enriched in the sn-2 position of TAG. In marked contrast to the transgenic seeds, conjugated fatty acids composed <1.5% of the fatty acids in PC from seeds of five unrelated species that naturally synthesize a variety of conjugated fatty acid isomers, including seeds that accumulate conjugated fatty acids to >80% of the total fatty acids. These results suggest that soybean and A. thaliana seeds are deficient in their metabolic capacity to selectively catalyze the flux of conjugated fatty acids from their site of synthesis on PC to storage in TAG.
金盏花、苦瓜和油桐中与Δ(12)-油酸去饱和酶相关的脂肪酸共轭酶在大豆（Glycine max）种子或拟南芥fad3/fae1突变体种子中的表达，伴随着共轭脂肪酸金盏花酸或α-桐酸的积累，其含量高达总脂肪酸的20%。由磷脂酰胆碱（PC）连接的底物合成的共轭脂肪酸，积累在PC和磷脂酰乙醇胺中，在转基因种子中，这些脂肪酸在PC中的相对含量高于三酰甘油（TAG）。在表达金盏花和苦瓜共轭酶的大豆和拟南芥种子的PC中检测到最高相对含量的共轭脂肪酸，它们占该脂质类脂肪酸的近25%。在这些种子中，PC中>85%的共轭脂肪酸在sn-2位被检测到，并且这些脂肪酸在TAG的sn-2位也有富集。与转基因种子形成鲜明对比的是，在自然合成多种共轭脂肪酸异构体的五个不相关物种的种子的PC中，共轭脂肪酸占脂肪酸的比例<1.5%，其中包括共轭脂肪酸积累量占总脂肪酸>80%的种子。这些结果表明，大豆和拟南芥种子在选择性催化共轭脂肪酸从其在PC上的合成位点向TAG储存的代谢通量方面存在缺陷。
