Abstract
Arabidopsis seeds contain a lot of oil bodies, which are surrounded by a lipid monolayer and store lipids mainly triacylglycerols. Oil bodies possess oleosins as major structural proteins and are formed in endoplasmic reticulum during seed maturation. Arabidopsis thaliana has four oleosins in seeds: AtOleS1 to 4. To investigate the role of oleosins in formation of oil body, we isolated each oleosin-deficient mutant of A. thaliana. The mutant plants exhibited wild-type appearance.Electron microscopy revealed that the mutant seeds had larger oil bodies than wild-type seeds. Both AtOleS3 and AtOleS4 are most abundant oleosins in seeds. The mutants, atoles3 and atoles4, developed abnormally larger oil bodies in seeds than the other mutants, atoles2 and atoles1. Our observations suggest that oleosins have an important role in determination of oil body size. We are now investigating the effect of large oil bodies on seed germination and subsequent seedling growth.
