A thraustochytrid diacylglycerol acyltransferase 2 with broad substrate specificity strongly increases oleic acid content in engineered Arabidopsis thaliana seeds.
A thraustochytrid diacylglycerol acyltransferase 2 with broad substrate specificity strongly increases oleic acid content in engineered Arabidopsis thaliana seeds.
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具有广泛底物特异性的破囊壶菌二酰基甘油酰基转移酶 2 可显着提高工程化拟南芥种子中的油酸含量
DOI：
10.1093/jxb/ert156
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发表时间：
2013-08
影响因子：
6.9
通讯作者：
Cahoon EB
中科院分区：
文献类型：
--
作者：
Zhang C;Iskandarov U;Klotz ET;Stevens RL;Cahoon RE;Nazarenus TJ;Pereira SL;Cahoon EB
二酰基甘油酰基转移酶（DGAT）催化酰基辅酶A依赖的三酰基甘油（TAG）生物合成的最后一步，并且是细胞油含量和质量的重要决定因素。在这项研究中，一个基因，命名为TaDGAT 2，编码2型DGAT（DGAT 2）相关酶被确定为产油海洋原生生物Thraustochytrium aureum。推导的TaDGAT 2序列含有约460个氨基酸的结构域，与来自Dictyosteobacterium sp.的DGAT 2s最密切相关（45-50%同一性）。重组TaDGAT 2恢复TAG生物合成的酿酒酵母H1246 TAG缺陷的突变体，并从补充突变体的微粒体显示DGAT活性与C16和C18饱和和不饱和的脂肪酰辅酶A和甘油二酯底物。为了研究其生物技术潜力，TaDGAT 2在野生型拟南芥和高亚油酸fad 3fae 1突变体中的强种子特异性启动子控制下表达。在这两种背景下，种子含油量变化不大，但种子油酸含量显着增加。这种增加在fad 3fae 1种子中最大，其中油酸的相对量增加了近2倍，达到总脂肪酸的>50%。此外，在三酰基甘油sn-2位置和主要种子磷脂磷脂酰胆碱中检测到油酸水平增加>2倍。这些结果表明，增加种子油酸含量介导的TaDGAT 2的影响，部分由宿主细胞的脂肪酸组成，并没有发生直接提高油酸含量在TAG sn-3的位置，但通过增加种子中的总油酸水平，大概是通过限制流量通过磷脂酰胆碱为基础的去饱和反应。
Diacylglycerol acyltransferase (DGAT) catalyses the last step in acyl-CoA-dependent triacylglycerol (TAG) biosynthesis and is an important determinant of cellular oil content and quality. In this study, a gene, designated TaDGAT2, encoding a type 2 DGAT (DGAT2)-related enzyme was identified from the oleaginous marine protist Thraustochytrium aureum. The deduced TaDGAT2 sequence contains a ~460 amino acid domain most closely related to DGAT2s from Dictyostelium sp. (45–50% identity). Recombinant TaDGAT2 restored TAG biosynthesis to the Saccharomyces cerevisiae H1246 TAG-deficient mutant, and microsomes from the complemented mutant displayed DGAT activity with C16 and C18 saturated and unsaturated fatty acyl-CoA and diacylglycerol substrates. To examine its biotechnological potential, TaDGAT2 was expressed under control of a strong seed-specific promoter in wild-type Arabidopsis thaliana and the high linoleic acid fad3fae1 mutant. In both backgrounds, little change was detected in seed oil content, but a striking increase in oleic acid content of seeds was observed. This increase was greatest in fad3fae1 seeds, where relative amounts of oleic acid increased nearly 2-fold to >50% of total fatty acids. In addition, >2-fold increase in oleic acid levels was detected in the triacylglycerol sn-2 position and in the major seed phospholipid phosphatidylcholine. These results suggest that increased seed oleic acid content mediated by TaDGAT2 is influenced in part by the fatty acid composition of host cells and occurs not by enhancing oleic acid content at the TAG sn-3 position directly but by increasing total oleic acid levels in seeds, presumably by limiting flux through phosphatidylcholine-based desaturation reactions.
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影响因子：
7.4
作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
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作者：
Luisa Hernandez, M.;Whitehead, Lynne;Graham, Ian A.
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Graham, Ian A.
影响因子：
2.3
作者：
GRAEF, GL;FEHR, WR;CIANZIO, SR
通讯作者：
CIANZIO, SR
影响因子：
7.4
作者：
Jako, C;Kumar, A;Taylor, DC
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Taylor, DC