S-locus-specific glycoproteins associated with self-incompatibility in Brassica campestris. Plant Cell Physiol

Specific S-glycoproteins were isolated from three Brassica campestris cultivars homozygous with respect to the 5-alleles Ss, S9 and Sl2. Amino acid sequences of various peptide fragments of the 5-proteins were determined using a gas-phase protein sequencer, and a nearly complete amino acid sequence of the 58-glycoprotein was determined on the basis of the revised cDNA sequence of the B. oleracea 5-specific glycoprotein. The lysyl endopeptidase fragments of S9 and 512-glycoproteins were aligned in comparison with the sequence of the Ss-glycoprotein. Although extensive sequence homology was evident among the three 5-glycoproteins, the sequences of the middle part were relatively different from each other. The numbers and positions of •/V-glycosylation also differed among the S-glycoproteins of Brassica species. Key words: Amino acid sequence — Brassica campestris — Brassica oleracea — Self-incompatibility — S-glycoprotein — 5-locus-specific glycoprotein. Flowers of many higher plants have an intraspecific recognition system between pollen and pistils, which controls self-incompatibility: pollen with a phenotype.identical to that of the pistil is prevented from normal pollen-tube growth and thus self-fertilization is prevented. Two types o