Genetic regulation of self‐incompatibility

Abstract

Self‐incompatibility is a cell‐cell recognition system in higher plants that is based on the ability of the pistil to discriminate “self‐pollen from “non‐self"‐pollen. In the simplest systems, this recognition response is controlled by a single locus — the S‐locus — with multiple alleles. Pollination of a pistil with pollen bearing an S‐allele recognition factor identical to that expressed in the host plant stigma or style results in rejection of the “self"‐pollen. Most of the studies on the molecular genetics of self‐incompatibility that are summarized in this review have had as their goal the identification and characterization of the gene product(s) associated with the self‐incompatibility response. These studies have provided a great deal of new and important information about self‐incompatibility — despite the fact that many critical questions remain unresolved. Taken together, the present evidence from these studies indicates that the self‐incompatibility response is likely to be far more complex than suggested by historical models.