Molecular typing of the self-incompatibility locus of Turkish sweet cherry genotypes reflects phylogenetic relationships among cherries and other Prunus species

摘要

Self-incompatibility of sweet cherry (Prunus avium L.) is controlled by the multiallelic S-locus. While many cultivars and wild accessions have been 5-genotyped, only limited data are available on accessions native to the center of origin of this species. Therefore, this study was carried out to determine the S-genotype of 11 landrace cultivars and 17 local genotypes selected from populations growing wild at the Black Sea coast. Eleven sweet cherries (S_1-S_7,S_(10), and S_(12)-S_(14)) and some wild cherries (S_(17))-S_(19), S_(21/25)and S_(31)) S-RNase alleles were detected. The results indicate that Turkish cultivars represent a broader gene pool as compared with international cultivars. A new (S_37) and a doubtful allele (provisionally labelled as S_(7m)) as well as the sour cherry S_(34)-allele were identified in sweet cherry. These data and others (SSR variants within the S_(13)-RNase introns) confirmed that allele pools of sweet and sour cherries in the Black Sea region are overlapping. A new cross-incompatibility group, XLV (S_2S_(18)), was also proposed. Allele-specific primers were designed for S_(17)-S_(19), S_(21/25), S_(34), and S_(37). A phylogenetic analysis of the cherry S_(31)- RNase and its trans-specific sister alleles reliably mirrored the assumed length of the time period after the divergence of species in the subgenera Cerasus and Prunophora. Most variations (insertions/deletions and single-nucleotide polymorphisms) in the S-RNase gene were silent and, hence, have not been exposed to natural selection. The results are discussed from the aspects of S-allele evolution and phylogenetic relationships among cherries and other Prunus species.