The S-RNase-based gametophytic self-incompatibility system in Prunus exhibits distinct genetic and molecular features

Abstract

Most Prunus fruit tree species exhibit a homomorphic gametophytic self-incompatibility (GSI) system, in which specificity of self/nonself-recognition is controlled by products encoded within the S locus. In the pollination event, a self-incompatibility (SI) reaction is triggered when the same “ S allele” specificity is expressed in both the pollen and pistil. During the last two decades, much progress has been made in our understanding of the molecular basis of the gametophytic self-incompatibility system in Prunus. Identification of the pistil S and pollen S determinants led to the development of PCR-based S genotyping and marker-assisted selection for self-compatible (SC) individuals. Molecular and genetic analyses of Prunus SC S haplotypes and polyploid sour cherry ( Prunus cerasus) reveal the possible existence of a distinct SI/SC recognition mechanism in the S-RNase-based GSI system of Prunus. This review summarizes the current molecular knowledge of the S-RNase-based GSI system in Prunus with reference to data collected for S-RNase-based GSI in other plants and its potential usefulness in SC breeding.