Localization of peanut (Arachis hypogaea) root lectin (PRA II) on root surface and its biological significance

The glucose-specific peanut root lectin, PRA II, is localized on the surface of 7-day-old peanut seedling root and in root cortical parenchymatous cells. The lectin is eluted from intact roots upon washing with buffer containing glucose. Rabbit erythrocytes bind to the root surface and the cortical cells; the binding is inhibited by antibodies raised against PRA II, peanut-specific Rhizobium cells and by glucose. Lipopolysaccharides isolated from host-specific Rhizobium strain inhibit the haemagglutinating activity of PRA II and are precipitated by the lectin. Our results suggest that PRA II might be involved in recognition of Rhizobium by peanut roots.