Role of bean lectins in Rhizobium phaseoli--Phaseolus vulgaris interactions. Some properties of lectins from two bean cultivars

Lectins from two Phaseolus vulgaris L. cultivars were isolated and purified by salt fractionation, affinity chromatography and gel permeation chromatography. The cultivars used were: "alubia", with a low-nodulating ability, and Bat 76 with a good symbiotic aptitude. Differences in properties of the two lectins were noted: "alubia" lectin gave only one peak with haemagglutinating activity following gel permeation chromatography while Bat 76 yielded two active peaks, although both lectins had several bands of about 30 kDa following gel electrophoresis, Bat 76 lectin had three bands of about 50 kDa which were not present in "alubia" and red kidney bean lectins. Peptide-mapping, by limited proteolysis and two dimensional gel electrophoresis, also showed differences between the lectins which are therefore judged to be different.