T-DNA Insertion Mutants Affecting Lipid Metabolism in Arabidopsis

传统的生物化学方法在研究参与脂质代谢的膜结合酶方面基本上是不成功的。拟南芥脂质生物合成缺陷突变体的特征为克隆相关基因提供了机会，而无需首先纯化相应的蛋白质。染色体行走无疑是成功的，但这种方法需要对每个克隆的基因付出巨大的努力。该项目确定是否可以在含有稳定整合T-DNA插入物的1800个拟南芥系群体中鉴定出任何脂质代谢突变。当发现突变并显示与位于T-DNA中的卡那霉素抗性标记共分离时，则需要大量的努力来完成该基因的克隆和表征。脂肪酸不饱和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体健康的重要性，能够控制这些物种的脂质不饱和程度将是有利的。实现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提供这一点，这些突变体用于分离和克隆编码负责去饱和的酶的基因。这进一步允许开发策略来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.