Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, F-78000 Versailles, France.
Plant Cell. 2012 Dec;24(12):5007-23. doi: 10.1105/tpc.112.106120. Epub 2012 Dec 14.
Acyl lipids are essential constituents of all cells, but acyl chain requirements vary greatly and depend on the cell type considered. This implies a tight regulation of fatty acid production so that supply fits demand. Isolation of the Arabidopsis thaliana WRINKLED1 (WRI1) transcription factor established the importance of transcriptional regulation for modulating the rate of acyl chain production. Here, we report the isolation of two additional regulators of the fatty acid biosynthetic pathway, WRI3 and WRI4, which are closely related to WRI1 and belong to the APETALA2-ethylene-responsive element binding protein family of transcription factors. These three WRIs define a family of regulators capable of triggering sustained rates of acyl chain synthesis. However, expression patterns of the three WRIs differ markedly. Whereas only WRI1 activates fatty acid biosynthesis in seeds for triacylglycerol production, the three WRIs are required in floral tissues to provide acyl chains for cutin biosynthesis and prevent adherence of these developing organs and subsequent semisterility. The targets of these WRIs encode enzymes providing precursors (acyl chain and glycerol backbones) for various lipid biosynthetic pathways, but not the subsequent lipid-assembling enzymes. These results provide insights into the developmental regulation of fatty acid production in plants.
酰基脂质是所有细胞的基本成分，但酰基链的需求差异很大，取决于所考虑的细胞类型。这意味着需要严格控制脂肪酸的产生，以确保供应与需求相匹配。拟南芥 WRINKLED1（WRI1）转录因子的分离确立了转录调控对于调节酰基链产生速率的重要性。在这里，我们报告了另外两个脂肪酸生物合成途径的调节剂 WRI3 和 WRI4 的分离，它们与 WRI1 密切相关，属于 APETALA2-乙烯响应元件结合蛋白家族的转录因子。这三个 WRI 定义了一个能够触发酰基链持续合成的调节因子家族。然而，这三个 WRI 的表达模式有很大的不同。虽然只有 WRI1 在种子中激活脂肪酸生物合成以产生三酰基甘油，但这三个 WRI 在花组织中是必需的，以提供酰基链用于角质层生物合成，并防止这些发育中的器官的粘连和随后的半不育。这些 WRI 的靶基因编码为各种脂质生物合成途径提供前体（酰基链和甘油骨架）的酶，但不是随后的脂质组装酶。这些结果为植物中脂肪酸产生的发育调控提供了深入的了解。
