Mechanism for the partitioning of glycerolipid biosynthetic pathways in leaves and seeds

在许多活生物体中，膜脂质和储存脂质均主要由甘油脂组成，其通常包含连接到甘油主链的两个或三个脂肪酸部分。在高等植物中，所有脂肪酸均在质体中合成，而膜和储存脂质生物合成的主要位点在细胞中在空间上分离。由于每个植物器官含有不同比例的两种类型的甘油脂，并且该比例本身是每个器官特性的主要特征之一，因此植物如何控制膜和储存甘油脂的两种不同生物合成途径的分配是令人感兴趣的。在这个项目中，我们研究了每个植物器官中膜和储存甘油脂生物合成两种不同途径的严格控制系统。在本研究过程中，我们发现几种营养缺乏条件甚至在叶子中也强烈增强了 TAG 合成，并阐明了磷脂酸磷酸水解酶 (PAH1/2) 在叶子 TAG 合成中的重要性。此外，我们还发现了缺乏对根部叶绿体膜生物发生的抑制的新突变体。

Both membrane and storage lipids are mainly composed of glycerolipids in many living organisms, which commonly contain two or three fatty acid moieties attached to a glycerol backbone. In case of higher plants, all of the fatty acids are synthesized in plastids, whereas the major sites for the membrane and storage lipid biosyntheses are spatially separated in a cell. Since each plant organ contain different ratio of the two types of the glycerolipids and the ratio itself is one of a major feature of each organ identity, it is of interest how plants control the partitioning of the two different biosynthetic pathways for the membrane and storage glycerolipids. In this project, we studied on the strict control system for the partitioning of two different pathways of membrane and storage glycerolipid biosyntheses in each plant organ. In the course of this study, we found several nutrient deficient conditions strongly enhanced TAG synthesis even in leaves, and clarified the importance of phosphatidate phosphohydrolase (PAH1/2) in the leaf TAG synthesis. Moreover, we identified novel mutants which lack suppression of chloroplast membrane biogenesis in roots.