Abstract
Self-incompatibility (SI) is a system to prevent inbreeding in angiosperms. In many species, SI is controlled by a single multiallelic locus, the S-locus. At least two genes must be localized at the S-locus, one encodes pistil S-determinant and the other encodes pollen S-determinant. The interaction between these S-determinants is expected to cause the SI response. The Solanaceae, Rosaceae, and Scrophulariaceae families possess gametophytic SI, and a polymorphic ribonuclease, termed S-RNase, has been shown to be the pistil S-determinant of SI. However, pollen S-determinant has never been identified in these families. In this work, we identified a candidate pollen S-determinant gene, termed SLF, in the vicinity of S-RNase gene of Japanese apricot, Prunus mume. SLF encodes a pollen-expressed F-box protein with an S-haplotype specific sequence polymorphism. Now, we are analyzing SLFs from other species.
