Lipid Metabolism and Photosynthesis in Fatty Acid Mutants ofArabidopsis

拟南芥脂肪酸突变体的脂质代谢和光合作用

• 批准号: 9105550
• 负责人: John Browse
• 金额: --
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1995-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9105550&HistoricalAwards=false
• 关键词: Lipid; Metabolism; Photosynthesis; Fatty; Acid

The acyl lipids of chloroplasts contain characteristically high proportions of trienoic fatty acids. Because this feature is universal among higher plants, it has been inferred that the fatty acid composition of chloroplast membranes is important for maintaining photosynthetic function. However, the enzymology and regulation of polyunsaturated fatty acid synthesis are poorly understood, and there is at present no accepted model of exactly how photosynthesis might be dependent on a highly unsaturated membrane. The principal investigator has isolated a series of Arabidopsis mutants with specific alterations in leaf fatty acid composition and these have provided a novel means to study both plant lipid metabolism and the physiological significance of membrane lipid composition. This proposal describes experiments to characterize the biochemistry of newly isolated mutants, and of double mutants produced by crossing mutant lines. This aspect of the project will involve assaying enzymes of fatty acid synthesis as well as in vivo labeling experiments and analysis of the fatty acid compositions of individual lipids and subcellular fractions. The most extreme double mutants are unable to grow autotrophically, but many of the mutations only affect growth and development of the plants at low temperatures. For this reason, photosynthesis in the different mutants will be analyzed under a range of environmental conditions using non-invasive fluorescence and light absorption techniques which can be used on intact plants. These experiments would provide a clear picture of exactly how photosynthesis is affected by thylakoid lipid composition under the different growth conditions normally encountered by temperate plants. The improved understanding of lipid metabolism and photosynthesis that will result from the work are important prerequisites to modifying these processes for increase plant productivity. //

叶绿体的酰基脂质含有高比例的三烯脂肪酸。由于这一特征在高等植物中是普遍的，因此已经推断叶绿体膜的脂肪酸组成对于维持光合功能是重要的。然而，酶学和多不饱和脂肪酸合成的调节知之甚少，目前还没有公认的模型，确切地说，光合作用可能是依赖于一个高度不饱和的膜。主要研究者已经分离出一系列拟南芥突变体，其叶片脂肪酸组成具有特定的改变，这些突变体为研究植物脂质代谢和膜脂组成的生理意义提供了新的手段。本提案描述了新分离的突变体和通过交叉突变株系产生的双突变体的生物化学特性的实验。该项目的这一方面将涉及测定脂肪酸合成酶以及体内标记实验和分析单个脂质和亚细胞组分的脂肪酸组成。最极端的双突变体不能自养生长，但许多突变只影响植物在低温下的生长和发育。出于这个原因，将在一系列环境条件下使用可用于完整植物的非侵入性荧光和光吸收技术分析不同突变体的光合作用。这些实验将提供一个明确的图片，究竟是如何光合作用的影响下，通常遇到的温带植物的不同生长条件下的类囊体脂质组合物。对脂质代谢和光合作用的进一步理解是修改这些过程以提高植物生产力的重要先决条件。//