In human milk fat, palmitic acid (16:0) is esterified to the middle (sn-2 or β) position on the glycerol backbone and oleic acid (18:1) predominantly to the outer positions, giving the triacylglycerol (TG) a distinctive stereoisomeric structure that is believed to assist nutrient absorption in the infant gut. However, the fat used in most infant formulas is derived from plants, which preferentially esterify 16:0 to the outer positions. We have previously showed that the metabolism of the model oilseed Arabidopsis thaliana can be engineered to incorporate 16:0 into the middle position of TG. However, the fatty acyl composition of Arabidopsis seed TG does not mimic human milk, which is rich in both 16:0 and 18:1 and is defined by the high abundance of the TG molecular species 1,3-olein-2-palmitin (OPO). Here we have constructed an Arabidopsis fatty acid biosynthesis 1-1 fatty acid desaturase 2 fatty acid elongase 1 mutant with around 20% 16:0 and 70% 18:1 in its seeds and we have engineered it to esterify more than 80% of the 16:0 to the middle position of TG, using heterologous expression of the human lysophosphatidic acid acyltransferase isoform AGPAT1, combined with suppression of LYSOPHOSPHATIDIC ACID ACYLTRANSFERASE 2 and PHOSPHATIDYLCHOLINE:DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE. Our data show that oilseeds can be engineered to produce TG that is rich in OPO, which is a structured fat ingredient used in infant formulas.

在人乳脂肪中，棕榈酸 (16:0) 被酯化到甘油骨架的中间 (sn-2 或 β) 位置，油酸 (18:1) 主要被酯化到外侧位置，使三酰基甘油 (TG)独特的立体异构结构被认为有助于婴儿肠道中的营养吸收。然而，大多数婴儿配方奶粉中使用的脂肪来自植物，它们优先以 16:0 酯化到外部位置。我们之前已经表明，模型油籽拟南芥的代谢可以设计为将 16:0 合并到 TG 的中间位置。然而，拟南芥种子 TG 的脂肪酰基组成与人乳不同，人乳富含 16:0 和 18:1，由 TG 分子种类 1,3-olein-2-palmitin 的高丰度定义。 OPO）。这里我们构建了拟南芥脂肪酸生物合成 1-1 脂肪酸去饱和酶 2 脂肪酸延长酶 1突变体在其种子中具有约 20% 16:0 和 70% 18:1，我们已对其进行工程改造，使用人溶血磷脂酸酰基转移酶同种型的异源表达，将超过 80% 的 16:0 酯化到 TG 的中间位置AGPAT1，结合抑制溶血磷脂酸酰基转移酶 2 和磷脂酰胆碱：二酰基甘油胆碱磷酸转移酶。我们的数据表明，油籽可以经过改造以生产富含 OPO 的 TG，OPO 是一种用于婴儿配方奶粉的结构化脂肪成分。