Cloning and Characterization of Twelve S-RNase Alleles in Japanese Apricot (Prunus mume Sieb. et Zucc.)

In this study, we cloned and sequenced PCR products from S-RNase alleles of 12 cultivars to determine their S-RNase genotypes or S haplotypes. We identified a novel S-11-RNase, which was previously misidentified as S-6-RNase. In addition, the first and second intron sizes of S-1- to S-11-, and S-f-RNases were presented. Since differences among the second intron sizes of S-3-, S-9-, and S-10-RNases, as well as those among S-5-, S-6-, and S-11-RNases, appeared to be very small, we developed primer sets for allele-specific PCR amplification to distinguish these S-RNase alleles. Consequently, 12 S-RNase alleles could be distinguished by PCR amplification using consensus primers for the second intron and/or the allele-specific primer sets. Using these PCR amplification, we determined S-RNase genotypes of 14 cultivars, including 'Kagajizo' ((SS10)-S-6), 'Baigo' ((SS10)-S-6), and 'Orihime' ((SSf)-S-11), whose S-RNase genotypes have been updated. The DNA sequence information for S-RNases and the allele-specific primer sets developed in this study would be useful for future S-RNase genotyping and thus S haplotyping in Japanese apricot.