STYLAR BASIC-PROTEINS CORRESPONDING TO 5 SELF-INCOMPATIBILITY ALLELESOF JAPANESE PEARS

This paper describes a series of style-specific proteins corresponding to five self-incompatibility alleles (S-protein), S-1 similar to S-5, in the Japanese pear (Pyrus serotina Rehd. culta Rehd.). Stylar prote ins from various cultivars including a few unclassified S-genotypes we re analyzed by isoelectricfocusing polyacrylamide gel electrophoresis (IEF-PBGE). The S-proteins were focused at the cathodic end of the gel when separated by IEF-PAGE using pH 3.5 similar to 9.5 ampholines. Th e pIs of these proteins were quite high, and each protein band was arr anged from a cathodic end in the following order: S-1, S-4, S-2, S-5 a nd S-3. This order was different from that reported by Sassa et al.(19 92, 1993). The S-1-, S-5- and S-3-band were densely stained with CBB ( Coomassie Brilliant Blue); whereas the S-2- and S-4-band were lightly stained, especially that of the S-2-band. 'Atago' (S2S5) and 'Matsukaz e' (S-genotype not identified) did not have any S-protein bands in the basic zone of the gel, suggesting that several S-allele associated pr oteins are present in the neutral or acidic zones of the gel. Each S-p rotein band exhibited ribonuclease (RNase) activity, though the activi ty was far weaker than in those proteins focused in the acidic zone of the IEF-PAGE gel.