Flax (Linum usitatissinum L.) oil is an important source of α-linolenic (C18:3 ω-3). This polyunsaturated fatty acid is well known for its nutritional role in human and animal diets. Understanding storage lipid biosynthesis in developing flax embryos can lead to an increase in seed yield via marker-assisted selection. While a tremendous amount of work has been done on different plant species to highlight their metabolism during embryo development, a comprehensive analysis of metabolic flux in flax is still lacking. In this context, we have utilized in vitro cultured developing embryos of flax and determined net fluxes by performing three complementary parallel labeling experiments with 13C-labeled glucose and glutamine. Metabolic fluxes were estimated by computer-aided modeling of the central metabolic network including 11 cofactors of 118 reactions of the central metabolism and 12 pseudo-fluxes. A focus on lipid storage biosynthesis and the associated pathways was done in comparison with rapeseed, arabidopsis, maize and sunflower embryos. In our hands, glucose was determined to be the main source of carbon in flax embryos, leading to the conversion of phosphoenolpyruvate to pyruvate. The oxidative pentose phosphate pathway (OPPP) was identified as the producer of NADPH for fatty acid biosynthesis. Overall, the use of 13C-metabolic flux analysis provided new insights into the flax embryo metabolic processes involved in storage lipid biosynthesis. The elucidation of the metabolic network of this important crop plant reinforces the relevance of the application of this technique to the analysis of complex plant metabolic systems.

中文翻译：

---

发育中的亚麻（Linum usitatissinum L.）胚胎中的13C代谢通量分析，以了解脂质的生物合成。

亚麻油（Linum usitatissinum L.）是α-亚麻酸（C18：3ω-3）的重要来源。这种多不饱和脂肪酸以其在人和动物饮食中的营养作用而闻名。了解发育中的亚麻胚中的脂质存储生物合成可以通过标记辅助选择导致种子产量增加。尽管已经在不同植物物种上进行了大量工作以突出它们在胚胎发育过程中的代谢，但是仍然缺乏对亚麻中代谢通量的全面分析。在这种情况下，我们利用体外培养的亚麻胚培养，并通过用13C标记的葡萄糖和谷氨酰胺进行三个互补的平行标记实验，确定了净通量。通过计算机辅助建模的中央代谢网络来估算代谢通量，该模型包括118个中央代谢反应的11个辅助因子和12个假通量。与油菜籽，拟南芥，玉米和向日葵胚相比，研究重点是脂质存储的生物合成及其相关途径。在我们手中，葡萄糖被确定为亚麻胚中碳的主要来源，从而导致磷酸烯醇丙酮酸转化为丙酮酸。氧化戊糖磷酸途径（OPPP）被确定为NADPH的脂肪酸生物合成生产者。总体而言，使用13 C代谢通量分析提供了有关参与储藏脂质生物合成的亚麻胚代谢过程的新见解。