Epsilon Open Archive

Abstract

New oil crops with high yield and oil content are urgently needed. Oat is the only cereal that accumulates substantial amount of lipids in the endosperm. This gives it potential as an oil crop, which could address both nutritional and environmental concerns of modern society. To develop oat with increased oil content, thorough investigations on its lipid metabolism and tools for genetic manipulations are needed.

Analyses of lipids in seeds of wild and cultivated oat species revealed variation in wild oat accessions in both oil content and quality. This variation should allow for development of new oat varieties for diverse applications. However, to develop oat as an oil crop, a level of 20% of the seed dry weight as oil is required and the range of oil content in the studied accessions was 4-10%. Another feature which showed almost no deviation was the amount of omega 3 fatty acid, -linolenic acid (0.6-2.1%). To develop oat varieties with ultra-high seed oil and increased content of omega 3 fatty acids, a biotechnological approach is preferred to conventional breeding methods.

Lipids in oat endosperm have been reported to exist, not enclosed in oil bodies, but as non-structured oil smear. In my study, I also observed oil smears, a phenomenon probably correlated with the reduced amount of oil body associated proteins in the endosperm, as revealed by microscopic and staining methods. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil body protein.

Biochemical studies on lipid mobilization during oat seed germination demonstrated efficient utilization of oil reserves from the starchy endosperm; these results were corroborated by microscopy. An oat cultivar which is capable of accumulating high amounts of oil in the endosperm was shown to be also efficient in utilizing these reserves upon germination.

Agrobacterium-mediated transformation is one of the methods for modification of oat oil content and/or its quality. The results of the analyses aimed at development of an Agrobacterium-mediated oat transformation protocol are presented in this thesis.