Involved in symbiosome development. Also associates directly or indirectly with the cell surface of Rhizobium bacteroids within the symbiosome. Glycosylation variants NLEC-1A and NLEC-1B are abundant in the peribacterial space while NLEC-1C is probably cytoplasmic. Expressed in nodules of Rhizobium-infected and uninfected roots and in the root stele near the nodule attachment point. In roots which have been colonized by the endomycorrhizal fungus G.versiforme, detected only in cortical cells colonized by the fungus, mainly those containing arbuscules. Expression increases gradually as nodules develop and then remains constant from 4 weeks to 2 months. Expressed at lower levels in senescing and non-fixing nodules. By infection with the endomycorrhizal fungus G.versiforme. Glycosylated in a boron-dependent manner. Glycosylation is required for localization to symbiosomes. 3 different glycosylation variants, NLEC-1A, NLEC-1B and NLEC-1C, have been identified. Belongs to the leguminous lectin family.