sentence: Within the Solanaceae , self-incompatibility is mediated by the “ S-locus ” which encodes a single female / stylar S-determinant ( i.e ., S-RNase ) and one or more pollen-expressed F-box proteins ( Iwano and Takayama 2012 ) that interact to cause pollen rejection when the male and female parent share the same allele at the S-locus ( McClure et al. 1989 ) .