Variations in and inheritance of ns-glycoprotein in self-incompatible brassica campestris l.

The stigma of Brassica species contain NS-glycoproteins that exhibit a high degree of structural homology to the S-glycoproteins of self-incompatibility. Inheritance of and variations in the NS-glycoprotein were studied with reference to self-incompatibility. The detection of NS-glycoproteins was performed by cross-reaction with an antiserum raised against a purified NS-glycoprotein. In B. campestris, four isoforms of the NS-glycoprotein were differentiated by their pI values, but their molecular weights were identical to one another. The genes for these isoforms of NS-glycoprotein were controlled by alleles at a single locus, tentatively named the NS allele, which was independent of S alleles at both the protein and the DNA level. Segregation of F₂ plants with respect to the self-incompatibility behavior of pollen tubes can be explained by the S allele model, but it appears not to be affected by the NS alleles. NS-glycoproteins were found in all 21 species of Brassica and its allies examined to date. The pI values of these glycoproteins varied among different species. In addition to the isoforms of the NS alleles, mature stigmas contained other groups of proteins that reacted weakly with the antiserum against the NS-glycoprotein.