Plants are non-motile organisms. It restricts access to vital elements like nitrogen, which is scare in different soils. To get better access to such nutrients plants evolved endosymbiotic interactions with N2- fixing bacteria. Legumes are able to establish an N2- fixing endosymbiosis with certain soil bacteria, collectively called rhizobium. This involves the formation of a new organ, the root nodule, which accommodates thousands of bacteria. In nodule cells rhizobia are surrounded by a membrane. It forms a unique symbiotic interface that facilitates exchange of nutrients between plant and bacteria. The symbiosome membrane belongs to the plant cell endomembrane system and intracellular accommodation of rhizobia causes drastic reorganizations of plant cells. In my thesis I focus on molecular mechanisms that control the rearrangement of the endomembrane system and actin skeleton in nodule cells during symbiosis development. Obtained results I discuss and integrate with related scientific literature.