Symbiotic nitrogen fixation at the late stage of nodule formation in Lotusjaponicus and other legume plants

After nodule organogenesis has been triggered by lipochitin oligosaccharide s (LCO) and early nodulin gene expression has started, the basic structure of the nodule tissue is formed. This early stage is believed to be independ ent of rhizobia invasion into host plant cell cytoplasm, and later signal e xchanges between plant cells and infected rhizobia are suggested to be esse ntial to establish a stable symbiotic relationship between host cell and sy mbiont, including late nodulin gene expressions concerning C/N flow in the nodule tissue. The nodule organogenesis results in an endocytological symbi osis that is important for nitrogen fixation and translocation of the produ cts to the shoot. Symbiotic metabolisms suggested to function in Lotus japo nicus nodules are reviewed, and current research data on Nod-35 (uricase) g ene, including that of Lotus japonicus as an example of a late nodulin gene are presented.