SPECIFIC AIMS The overall goal of this project is to understand the role of membrane lipids in the organization and functioning of plant cells and organelles. This project has the following specific aims: 1. To carry out the lipid analyses and labelling studies required to characterize arabidopsis mutants already selected. 2. To investigate the photosynthetic characteristics of those mutants in which the fatty acid compositions of chloroplast lipids are affected. 3. To construct double mutants with more extensive changes in chloroplast fatty acid composition and to study photosynthesis in these also. 4. To screen independent M2 populations for further mutants and alleles of existing mutants. Results so far obtained indicate that these mutants can provide considerable information on the enzymology of desaturation and on the control of cellular lipid metabolism. More importantly the mutants provide a means of directly addressing the question of how the fatty acid composition of thylakoid membranes affects chloroplast structure and function.%%% Increased knowledge in these areas is an essential prerequisite to intelligently manipulating membrane lipid composition by recombinant DNA techniques. For example, because of the possible importance of membrane lipid composition in the temperature responses to plants, a detailed understanding of fatty acid desaturation and the genes which control this process may make it possible to genetically modify economically important crop species to better suit particular environmental conditions.***
