Abstract
Self-incompatibility (SI) systems prevent self-pollination and promote outbreeding. In the SI response of Brassica, self-pollen is rejected at the surface of the papilla cells due to recognition of self and non-self-pollen. This system is sporophytically controlled by a single S locus with multiple alleles.
The S locus region has been dissected to identify highly polymorphic SI genes, SLG, SRK, and SP11. We demonstrated that SRK and SP11/SCR are female and male determinants of the SI recognition, respectively. Recent studies showed that SRK on the stigma surface could bind to the ligand, SP11, in an allele-specific manner. For SLG's function, SLG can enhance the SI phenotype.
Recently, we observed a linear dominant-recessive relationship in pollen. It was found that the linear dominance-recessiveness of the SI phenotype in pollen was regulated by expression of SP11.
