Differentiation of nitrogen-fixing nodules of Sesbania rostrata with special reference to oleosomes (lipid bodies)

The study on Sesbania rostrata focused on the development and differentiation of nitrogen-fixing nodules, highlighting the role of oleosomes (lipid bodies) in these processes. The bacterium Azorhizobium caulinodans IRG 46 was found to enter the host plant through fissures, leading to the formation of infection thread-like structures. A notable finding was the presence of large oleosomes in stem nodules, up to eight times larger than those in root nodules, likely due to an oversupply of photosynthate. These oleosomes, which store photosynthate as triacylglycerol, disappear after cell maturation. The study also identified lipolytic and catalase activities in the nodules, with higher catalase activity in the host cytosol. Lipid analysis revealed differences in fatty acid composition between stem and root nodules and seeds. Overall, oleosomes were used for cell growth and development but were not directly involved in nitrogen fixation.