Self-compatibility in Prunus species : diversity of mutations

Abstract

Self-compatibility (SC) is an interesting horticultural trait. Molecular approaches have been recently applied to the elucidation of the interacting pollen-pistil mechanism and to the identification of the genes involved in pistil-pollen recognition. Both mutations of the pistil S-RNases and the pollen SFBs have been reported to explain the changes in the S allele expression. Stylar-part mutations have revealed that ribonuclease activity of the S-RNases is required to inhibit pollen growth. A defective function of the pollen may also give rise to SC. Breakdown of SI has also been associated with mutations affecting modifier loci unlinked to the S-locus. Additionally, a double phenotypic expression of the same genotype has been observed. The nature of these different mutations has only been identified in a few cases, including deletions, insertions, shift mutations and, more recently, epigenetic changes.