The de novo synthesis of fatty acids in plants occurs in the plastids through the activity of fatty acid synthetase. The synthesis of the malonyl-coenzyme A that is required for acyl-chain elongation requires the import of metabolites from the cytosol and their subsequent metabolism. Early studies had implicated acetate as the carbon source for plastidial fatty acid synthesis but more recent experiments have provided data that argue against this. A range of cytosolic metabolites including glucose 6-phosphate, malate, phosphoenolpyruvate and pyruvate support high rates of fatty acid synthesis by isolated plastids, the relative utilisation of which depends upon the plant species and the organ from which the plastids are isolated. The import of these metabolites occurs via specific transporters on the plastid envelope and recent advances in the understanding of the role of these transporters are discussed. Chloroplasts are able to generate the reducing power and ATP required for fatty acid synthesis by capture of light energy in the reactions of photosynthetic electron transport. Regulation of chloroplast fatty acid synthesis is mediated by the response of acetyl-CoA carboxylase to the redox state of the plastid, which ensures that the carbon metabolism is linked to the energy status. The regulation of fatty acid synthesis in plastids of heterotrophic cells is much less well understood and is of particular interest in the tissues that accumulate large amounts of the storage oil, triacylglycerol. In these heterotrophic cells the plastids import ATP and oxidise imported carbon sources to produce the required reducing power. The sequencing of the genome of Arabidopsis thaliana has now enabled a number of aspects of plant fatty acid synthesis to be re-addressed, particularly those areas in which in vitro biochemical analysis had provided equivocal answers. Examples of such aspects and future opportunities for our understanding of plant fatty acid synthesis are presented and discussed.

中文翻译：

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植物中的碳通量和脂肪酸合成。

植物中脂肪酸的从头合成通过脂肪酸合成酶的活性在质体中发生。酰基链延长所需的丙二酰辅酶A的合成需要从细胞质中导入代谢产物并随后进行代谢。早期研究表明乙酸盐是质体脂肪酸合成的碳源，但最近的实验提供了与此相反的数据。包括6-磷酸葡萄糖，苹果酸，磷酸烯醇丙酮酸和丙酮酸在内的多种胞质代谢产物通过分离的质体支持脂肪酸合成的高速率，其相对利用率取决于植物种类和从中分离质体的器官。这些代谢物的输入是通过质体包膜上的特定转运蛋白进行的，并讨论了关于这些转运蛋白作用的最新进展。叶绿体能够通过捕获光合电子传输反应中的光能来产生脂肪酸合成所需的还原能力和ATP。叶绿体脂肪酸合成的调节由乙酰辅酶A羧化酶对质体的氧化还原状态的响应介导，这确保了碳代谢与能量状态相关。异养细胞质体中脂肪酸合成的调控了解得很少，并且在积累大量储存油三酰甘油的组织中特别引起关注。在这些异养细胞中，质体输入ATP并氧化输入的碳源以产生所需的还原力。现在，拟南芥基因组的测序使植物脂肪酸合成的许多方面得以重新解决，特别是在体外生化分析提供了模棱两可的答案的那些领域。提出和讨论了这些方面的例子以及我们对植物脂肪酸合成的理解的未来机会。