Genetic and molecular characterization of three novel S-haplotypes in sour cherry (Prunus cerasus L.).
Tetraploid sour cherry (Prunus cerasus L.) exhibits gametophytic self-incompatibility (GSI) whereby the specificity of self-pollen rejection is controlled by alleles of the stylar and pollen specificity genes, S-RNase and SFB (S haplotype-specific F-box protein gene), respectively. As sour cherry selections can be either self-compatible (SC) or self-incompatible (SI), polyploidy per se does not result in SC. Instead the genotype-dependent loss of SI in sour cherry is due to the accumulation of non-functional S-haplotypes. The presence of two or more non-functional S-haplotypes within sour cherry 2x pollen renders that pollen SC. Two new S-haplotypes from sour cherry, S(33) and S(34), that are presumed to be contributed by the P. fruticosa species parent, the complete S-RNase and SFB sequences of a third S-haplotype, S(35), plus the presence of two previously identified sweet cherry S-haplotypes, S(14) and S(16) are described here. Genetic segregation data demonstrated that the S(16)-, S(33)-, S(34)-, and S(35)-haplotypes present in sour cherry are fully functional. This result is consistent with our previous finding that 'hetero-allelic' pollen is incompatible in sour cherry. Phylogenetic analyses of the SFB and S-RNase sequences from available Prunus species reveal that the relationships among S-haplotypes show no correspondence to known organismal relationships at any taxonomic level within Prunus, indicating that polymorphisms at the S-locus have been maintained throughout the evolution of the genus. Furthermore, the phylogenetic relationships among SFB sequences are generally incongruent with those among S-RNase sequences for the same S-haplotypes. Hypotheses compatible with these results are discussed.
Tsukamoto
Tatsuya
T
Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA.
Potter
Daniel
D
Tao
Ryutaro
R
Vieira
Cristina P
CP
Vieira
Jorge
J
Iezzoni
Amy F
AF
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D044783:F-Box Proteins / Q000235:genetics*; D017343:Genes, Plant; D006239:Haplotypes; D008969:Molecular Sequence Data; D010802:Phylogeny; D027861:Prunus / Q000235:genetics*; D012260:Ribonucleases / Q000235:genetics*; D017422:Sequence Analysis, DNA
D044783:F-Box Proteins; D012260:Ribonucleases