Phytyl ester and triacylglycerol synthesis in plants, green algae and cyanobacteria

植物、绿藻和蓝细菌中植酯和三酰甘油的合成

• 批准号: 229052062
• 负责人: Professor Dr. Peter Dörmann
• 金额: --
• 依托单位: Institut für Molekulare Physiologie und Biotechnologie der Pflanzen (IMBIO)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/229052062?language=en
• 关键词: Phytyl; ester; triacylglycerol; synthesis; plants

Plants, green algae and cyanobacteria convert light into chemical energy by oxygenic photosynthesis employing chlorophyll for the collection of photons. Chlorophyll is subject to turnover processes resulting in the release of free phytol which is toxic to the cell. We recently isolated two phytyl ester synthases (PES1, PES2) from Arabidopsis which belong to the esterase/lipase/thioesterase (ELT) family of acyltransferases. PES1 and PES2 convert free phytol into fatty acid phytyl esters, thereby removing phytol from metabolism. Therefore, this pathway represents a novel mechanism involved in the regulation of chlorophyll turnover in plants. PES1 and PES2 produce phytyl esters and triacylglycerol in vitro, but it remained unclear whether they also produce triacylglycerol in vivo. Arabidopsis contains four additional ELT genes with sequence similarity to PES1/PES2, and three orthologous genes are found in the green alga Chlamydomonas. In Synechocystis, two genes covering parts of PES1/PES2 are present. In this project, we will study the role of these genes for phytyl ester and triacylglycerol metabolism in Arabidopsis, Chlamydomonas and Synechocystis. We will address the question, whether triacylglycerol synthesis in plant chloroplasts is dependent on PES1/PES2 or other ELT genes. We will study the contribution of the PES genes for triacylglycerol synthesis in Chlamydomonas, and analyze whether these genes can represent targets for biotechnological strategies to improve the oil content in green algae. Furthermore, we will address the question whether the phytyl ester pathway is of cyanobacterial origin.

植物、绿色藻类和蓝细菌通过利用叶绿素收集光子的产氧光合作用将光转化为化学能。叶绿素经历周转过程，导致释放对细胞有毒的游离植醇。我们最近从拟南芥中分离到两种植酯酶（PES 1，PES 2），属于酯酶/脂肪酶/硫酯酶（ELT）家族。PES 1和PES 2将游离植醇转化为脂肪酸植醇酯，从而从代谢中去除植醇。因此，这一途径代表了一种新的机制，参与调节植物叶绿素周转。PES 1和PES 2在体外产生植酯和三酰甘油，但仍不清楚它们是否也在体内产生三酰甘油。拟南芥含有四个额外的ELT基因，其序列与PES 1/PES 2相似，并且在绿色拟南芥衣原体中发现三个正向同源基因。在集胞藻中，存在覆盖PES 1/PES 2部分的两个基因。在本项目中，我们将研究这些基因在拟南芥、披衣藻和集胞藻中的作用。我们将解决的问题，是否三酰甘油在植物叶绿体的合成是依赖于PES 1/PES 2或其他ELT基因。我们将研究披衣藻中三酰甘油合成的PES基因的贡献，并分析这些基因是否可以代表生物技术策略的目标，以提高绿色藻类中的油含量。此外，我们将解决的问题植酯途径是否是蓝藻起源。