Self-incompatibility in flowering plants: the Brassica model.

Self-incompatibility (SI) is a widespread mechanism in flowering plants that prevents self-fertilization. Self-pollen recognition relies on the products of genes located at the S (self-incompatibility) locus. Significant progress towards understanding molecular interactions allowing stigmatic cells to recognize and reject self-pollen in Brassica has been made during the past two years. Thus, the male and female determinants responsible of the self-incompatibility (SI) response have been identified. The structural features of these molecules strongly suggest that SI response is triggered by a ligand-receptor interaction.