Oil Body Biogenesis during Brassica napus Embryogenesis

Although the oil body is known to be an important membrane enclosed compartment for oil storage in seeds, we have little understanding about its biogenesis during embryogenesis. In the present study we investigated the oil body emergence and variations in Brassica napus cv. Topas. The results demonstrate that the oil bodies could be detected already at the heart stage, at the same time as the embryos began to turn green, and the starch grains accumulated in the chloroplast stroma. In comparison, we have studied the development of oil bodies between Arabidopsis thaliana wild type （Col） and the low-seed-oil mutant wrinkled1-3. We observed that the oil body development in the embryos of Col is similar to that of B. napus cv. Topas, and that the size of the oil bodies was obviously smaller in the embryos of wrinkled1-3. Our results suggest that the oil body biogenesis might be coupled with the embryo chloroplast.

Localization of Seed Oil Body Proteins in Tobacco Protoplasts Reveals Specific Mechanisms of Protein Targeting to Leaf Lipid Droplets

Oleosin, caleosin and steroleosin are normally expressed in developing seed cells and are targeted to oil bodies. In the present work, the cDNA of each gene tagged with fluorescent proteins was transiently expressed into tobacco protoplasts and the fluorescent patterns observed by confocal laser scanning microscopy. Our results indicated clear differences in the endocellular localization of the three proteins. Oleosin and caleosin both share a common structure consisting of a central hydrophobic domain flanked by two hydrophilic domains and were correctly targeted to lipid droplets （LD）, whereas steroleosin, characterized by an N-terminal oil body anchoring domain, was mainly retained in the endoplasmic reticulum （ER）. Protoplast fractionation on sucrose gradients indicated that both oleosin and caleosin- green fluorescent protein （GFP） peaked at different fractions than where steroleosin-GFP or the ER marker binding immunoglobulin protein （BiP）, were recovered. Chemical analysis confirmed the presence of triacylglycerols in one of the fractions where oleosin-GFP was recovered. Finally, only oleosin- and caleosin-GFP were able to reconstitute artificial oil bodies in the presence of triacylglycerols and phospholipids. Taken together, our results pointed out for the first time that leaf LDs can be separated by the ER and both oleosin or caleosin are selectively targeted due to the existence of selective mechanisms controlling protein association with these organelles.

Plant as Bioreactor for Producing Heterologous Proteins

Using plants to produce heterologous proteins makes it very attractive due to the potentially low costs. Using this procedure it is possible to produce medicinal protein for clinical applications with the plants bioreactors increasing gradually. The paper proposes the five major systems of the plant bioreactor as well as their advantage and disadvantage and the development of each system. Focuses on the five major systems of the plant bioreactor to produce vaccines, antibodies and medical protein and the research achievement at the present stage and the research on my laboratory. The key technology research of plant bioreactor such as new genes, new biological components, new technologies and new research methods related with plant bioreactor offer a work foundation for a long-term development in future.