Plant lipids represent a fascinating field of scientific study, in part due to a stark dichotomy in the limited fatty acid (FA) composition of cellular membrane lipids versus the huge diversity of FAs that can accumulate in triacylglycerols (TAGs), the main component of seed storage oils. With few exceptions, the strict chemical, structural, and biophysical roles imposed on membrane lipids since the dawn of life has constrained their FA composition to predominantly lengths of 16-18 carbons and containing 0-3 methylene-interrupted carbon-carbon double bonds in cis-configuration. However, over 450 “unusual” FA structures can be found in seed oils of different plants (Ohlrogge et al., 2018), and we are just beginning to understand the metabolic mechanisms required to produce and maintain this dichotomy. Here we review the current state of plant lipid research, specifically addressing the knowledge gaps in membrane and storage lipid synthesis from three angles: pathway fluxes including newly discovered TAG remodeling, key acyltransferase substrate selectivities, and the possible roles of “metabolons”.

中文翻译：

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合理控制种子油成分：解剖细胞组织和脂质代谢的通量控制


植物脂质代表了一个引人入胜的科学研究领域，部分原因是细胞膜脂质的有限脂肪酸 （FA） 组成与可能在种子储存油的主要成分三酰甘油 （TAG） 中积累的 FA 的巨大多样性存在鲜明的二分法。除了少数例外，自生命诞生以来，膜脂质就被施加在严格的化学、结构和生物物理作用上，使它们的 FA 组成主要限于 16-18 个碳的长度，并包含 0-3 个亚甲基中断的碳-碳双键，呈顺式构型。然而，在不同植物的种子油中可以找到超过 450 种“不寻常”的 FA 结构（Ohlrogge等人，2018 年），我们才刚刚开始了解产生和维持这种二分法所需的代谢机制。在这里，我们回顾了植物脂质研究的现状，特别是从三个角度解决了膜和储存脂质合成中的知识空白：途径通量，包括新发现的 TAG 重塑、关键的酰基转移酶底物选择性以及“代谢子”的可能作用。