ABSTRACT Aminoalcoholphosphotransferase (AAPT) utilizes diacylglycerols and cytidine diphosphate-choline/ethanolamine as substrates for the synthesis of phosphatidylcholine (PC)/phosphatidylethanolamine (PE). Plant AAPTs involved in phospholipid metabolism mediate diverse physiological processes; however, little is known about their functions in triacylglycerol (TAG) metabolism and seed germination. In the present study, we isolated and characterized two AAPTs, GmAAPT1 and GmAAPT2, from soybean (Glycine max). GmAAPT1 and GmAAPT2 exhibited strong similarity in their amino acid contents and expression patterns, and both were found to localize to the endoplasmic reticulum and Golgi apparatus. In vitro enzymatic analyses showed that GmAAPT1 and GmAAPT2 contributed to PC and PE synthesis and exhibited choline/ethanolamine phosphotransferase-like enzymatic properties. The overexpression of GmAAPT1 and GmAAPT2 in Arabidopsis led to reduced levels of seed TAG and polyunsaturated fatty acids and decreased seed germination under freezing stress. Together, these findings suggest that GmAAPTs mediate TAG metabolism and negatively regulate seed freezing tolerance.

中文翻译：

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大豆 (Glycine max) 中 GmAPT 的分子克隆和功能表征


摘要 氨基醇磷酸转移酶（AAPT）利用二酰甘油和胞苷二磷酸胆碱/乙醇胺作为底物合成磷脂酰胆碱（PC）/磷脂酰乙醇胺（PE）。参与磷脂代谢的植物 AAPT 介导多种生理过程；然而，人们对它们在三酰甘油（TAG）代谢和种子萌发中的功能知之甚少。在本研究中，我们从大豆 (Glycine max) 中分离和表征了两种 AAPT：GmAAPT1 和 GmAAPT2。 GmAAPT1 和 GmAAPT2 在氨基酸含量和表达模式方面表现出高度相似性，并且均被发现定位于内质网和高尔基体。体外酶分析表明，GmAAPT1 和 GmAAPT2 有助于 PC 和 PE 的合成，并表现出类似胆碱/乙醇胺磷酸转移酶的酶特性。拟南芥中 GmAAPT1 和 GmAAPT2 的过度表达导致种子 TAG 和多不饱和脂肪酸水平降低，并降低冷冻胁迫下种子的发芽率。总之，这些发现表明 GmAAPT 介导 TAG 代谢并负向调节种子冷冻耐受性。