T-DNA Insertion Mutants Affecting Lipid Metabolism in Arabidopsis

传统的生化方法在研究与脂类代谢有关的膜结合酶方面基本上是不成功的。缺乏脂质生物合成的拟南芥突变体的特征为克隆相关基因提供了机会，而不需要首先纯化相应的蛋白质。染色体行走无疑将是成功的，但这种方法需要对每个克隆的基因进行非常大量的努力。这个项目决定了是否可以在含有稳定整合的T-DNA插入片段的1800个拟南芥品系中鉴定出任何脂肪代谢的突变。当发现突变并显示与位于T-DNA的卡那霉素抗性标记共分离时，完成该基因的克隆和特性的大量工作是合理的。脂肪酸不饱和度是油料作物产品质量和经济价值的决定因素。由于不饱和脂肪酸对人类健康的重要性，能够控制这些物种中脂肪的不饱和程度将是有利的。迈向这一目标的关键一步是了解去饱和的分子基础。这项研究通过鉴定脂肪酸突变体来分离和克隆编码负责降低饱和度的酶的基因，从而提供了这一点。这进一步允许制定战略，有效地改变植物油的脂肪酸组成。

Traditional biochemical approaches have been largely unsuccessful in the study of the membrane-bound enzymes involved in lipid metabolism. The characterization of mutants of Arabidopsis deficient in lipid biosynthesis provides opportunities to clone the genes involved without first purifying the corresponding proteins. Chromosome walking will undoubtedly be successful, but this approach requires a very large amount of effort for each gene cloned. This project determines whether any mutants in lipid metabolism can be identified in a population of 1,800 Arabidopsis lines containing stably integrated T-DNA inserts. When a mutation is found and shown to cosegregate with the kanamycin resistance marker located in the T-DNA, then a substantial effort to complete the cloning and characterization of the gene is justified. Fatty acid unsaturation is a determinant of the quality and economic value of the product from oilseed crop species. Because of the importance of unsaturated fatty acids in human health, it would be advantageous to be able to control the degree of unsaturation of the lipids in these species. A crucial step toward this goal is to understand the molecular basis of desaturation. This research provides for this by identifying fatty acid mutants to be used for the isolation and cloning of genes encoding the enzymes responsible for desaturation. This further allows for the development of strategies to alter usefully the fatty acid composition of vegatable oils.