Yunus Ian Sofian, Liu Yu-Chi, Nakamura Yuki
Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
Plant J. 2016 Nov;88(4):559-569. doi: 10.1111/tpj.13278. Epub 2016 Oct 17.
In plants, ethanolamine is considered a precursor for the synthesis of choline, which is an essential dietary nutrient for animals. An enzyme serine decarboxylase (SDC) has been identified and characterized in Arabidopsis, which directly converts serine to ethanolamine, a precursor to phosphorylethanolamine and its subsequent metabolites in plants. However, the importance of SDC and ethanolamine production in plant growth and development remains unclear. Here, we show that SDC is required for ethanolamine biosynthesis in vivo and essential in plant embryogenesis in Arabidopsis. The knockout of SDC1 caused an embryonic lethal defect due to the developmental arrest of the embryos at the heart stage. During embryo development, the expression was observed at the later stages, at which developmental defect occurred in the knockout mutant. Overexpression of SDC1 in planta increased levels of ethanolamine, phosphatidylethanolamine, and phosphatidylcholine both in leaves and siliques. These results suggest that SDC1 plays an essential role in ethanolamine biosynthesis during the embryogenesis in Arabidopsis.
在植物中，乙醇胺被认为是胆碱合成的前体，而胆碱是动物必需的膳食营养素。在拟南芥中已鉴定并表征了一种丝氨酸脱羧酶（SDC），它可直接将丝氨酸转化为乙醇胺，乙醇胺是植物中磷酸乙醇胺及其后续代谢产物的前体。然而，SDC和乙醇胺产生在植物生长发育中的重要性仍不清楚。在此，我们表明SDC在体内乙醇胺生物合成中是必需的，并且在拟南芥的植物胚胎发生中至关重要。SDC1的敲除导致胚胎致死缺陷，原因是胚胎在心脏期发育停滞。在胚胎发育过程中，在后期观察到该基因的表达，而敲除突变体在该阶段出现发育缺陷。在植物中过表达SDC1会增加叶片和角果中乙醇胺、磷脂酰乙醇胺和磷脂酰胆碱的水平。这些结果表明，SDC1在拟南芥胚胎发生过程中的乙醇胺生物合成中起重要作用。
