As plant seed oils provide animals with essential fatty acids (FAs), genes that regulate plant lipid metabolism have been used in genetic manipulation to improve dietary seed oil composition and benefit human health. Herein, the Arabidopsis thaliana cytosolic acyl‐CoA‐binding proteins (AtACBPs), AtACBP4, AtACBP5, and AtACBP6 were shown to play a role in determining seed oil content by analysis of atacbp (atacbp4, atacbp5, atacbp6, atacbp4atacbp5, atacbp4atacbp6, atacbp5atacbp6, and atacbp4atacbp5atacbp6) seed oil content in comparison with the Col‐0 wild type (WT). Triacylglycerol (TAG) composition in electrospray ionization‐mass spectrometer (ESI‐MS) analysis on atacbp6 seed oil showed a reduction (−50%) of C58‐TAGs in comparison with the WT. Investigations on fatty acid composition of atacbp mutants indicated that 18:2‐FA accumulated in atacbp6 and 18:3‐FA in atacbp4, both at the expense of 20:1‐FA. As TAG composition can be modified by acyl editing through phosphatidylcholines (PC) and lysophosphatidylcholines (LPC), total PC and LPC content in atacbp6 mature seeds was determined and ESI‐MS analysis revealed that LPC had increased (+300%) at the expense of PC. Among all the 14 tested PC species, all (34:1‐, 34:2‐, 34:3‐, 34:4‐, 34:5‐, 34:6‐, 36:2‐, 36:3‐, 36:5‐, 36:6‐, 38:2‐, 38:3‐, and 38:4‐PCs) but 36:4‐PC were lower in atacbp6 than the WT. In contrast, all LPC species (16:0‐, 18:1‐, 18:2‐, 18:3‐, and 20:1‐LPC) examined were elevated in atacbp6. LPC abundance also increased in atacbp4atacbp5, but not atacbp4 and atacbp5. Interestingly, when LPC composition in atacbp4atacbp5 was compared with atacbp4 and atacbp5, significant differences were observed between atacbp4atacbp5 and each single mutant, implying that AtACBP4 and AtACBP5 play combinatory roles by affecting LPC (but not PC) biosynthesis. Furthermore, PC‐related genes such as those encoding acyl‐CoA:lysophphosphatidylcholine acyltransferase (LPCAT1) and phospholipase A2 alpha (PLA2α) were upregulated in atacbp6 developing seeds. A model on the role of AtACBP6 in modulating TAG through regulating LPCAT1 and PLA2α expression is proposed. Taken together, cytosolic AtACBPs appear to affect unsaturated TAG content and are good candidates for engineering oil crops to enhance seed oil composition.

中文翻译：

---

拟南芥胞质酰基辅酶A结合蛋白在确定种子油成分中起作用。

由于植物种子油可为动物提供必需脂肪酸（FA），因此调节植物脂质代谢的基因已用于基因操作中，以改善饮食中种子油的成分并有益于人类健康。这里，拟南芥胞质酰基辅酶A结合蛋白（AtACBPs），AtACBP4，AtACBP5和AtACBP6分别显示出在通过的分析来确定种子油含量作用atacbp（atacbp4，atacbp5，atacbp6，atacbp4atacbp5，atacbp4atacbp6，atacbp5atacbp6，与野生型Col-0（WT）相比，种子油含量和atacbp4atacbp5atacbp6）。电喷雾电离质谱仪（ESI-MS）中atacbp6上的三酰基甘油（TAG）成分与野生型油相比，种子油的C58-TAG含量降低了（-50％）。对atacbp突变体的脂肪酸组成的研究表明，atacbp6中积累了18：2-FA且atacbp4中积累了18：3-FA ，两者均以20：1-FA为代价。由于可以通过磷脂酰胆碱（PC）和溶血磷脂酰胆碱（LPC）进行酰基编辑来修饰TAG的组成，因此确定了atacbp6成熟种子中PC和LPC的总含量，ESI-MS分析表明LPC增加了（+ 300％），而代价是电脑 在这14种经过测试的PC物种中，所有（34：1-，34：2-，34：3-，34：4-，34：5-，34：6-，36：2-，36：3-， 36：5‐，36：6‐，38：2‐，38：3‐和38：4‐PC），但是atacbp6中36：4‐PC较低比WT。相反，所检查的所有LPC种类（16：0‐，18：1‐，18：2‐，18：3‐和20：1‐LPC）的atacbp6均升高。LPC的丰度也增加atacbp4atacbp5，但没有增加atacbp4和atacbp5。有趣的是，将atacbp4atacbp5中的LPC组成与atacbp4和atacbp5进行比较时，发现atacbp4atacbp5之间存在显着差异以及每个单个突变体，暗示AtACBP4和AtACBP5通过影响LPC（而非PC）的生物合成发挥组合作用。此外，在atacbp6发育中的种子中，与PC相关的基因，例如编码酰基CoA：溶血磷脂酰胆碱酰基转移酶（LPCAT1）和磷脂酶A2α（PLA2α）的基因被上调。提出了一个AtACBP6通过调节LPCAT1和PLA2α表达来调节TAG作用的模型。两者合计，胞质AtACBPs似乎会影响不饱和TAG含量，是工程油料作物增强种子油成分的良好候选者。