Abstract
The pollen-pistil interactions that precede fertilization have been recognized as being a useful model system for investigating cell-cell communication in plants. Significant insight into the cell-cell signaling has been provided by the study of self-incompatibility (SI) system. SI is a widespread mechanism in flowering plants that prevents inbreeding. In many families, SI is genetically controlled by a multi-allelic gene complex at a single locus, called S-locus. The self/non-self discrimination is expected to occur as a result of interaction between pollen and pistil determinants encoded at the S-locus. In recent years, considerable progress has been made in identifying the determinants. Interestingly, the identified determinants from different plant families vary with respect to molecular structure and function, suggesting that quite diverse mechanisms have been recruited for the rejection of self-incompatible pollen. Commonalities and differences among SI systems will be discussed.
