Molecular characterization of S -RNase genes and S -genotypes in the Japanese apricot ( Prunus mume Sieb. et Zucc.)

Abstract

Three partial S-RNase genes, MSRN-1, MSRN-2, and MSRN-3, in the Japanese apricot (Prunusmume Sieb. et Zucc.) were isolated from the three cultivars Nankou, Gyokuei, and Kairyouuchidaume, respectively. The structural characteristics revealed that S-RNase genes from the Japanese apricot were in the T2/SRNase-type S-RNase family with five conserved regions (C1, C2, C3, RC4, and C5) and one variable region (RHV) as reported in the other rosaceous plants. In the phylogenetic tree of T2/S SRNase-type RNases, three S-RNase genes of the Japanese apricot did not form a species-specific subgroup but the Prunus subfamily did. At least seven S-allelic genes were present in the Japanese apricot, and S-genotypes of six representative cultivars, including Nankou, Gyokuei, Kairyouuchidaume, Baigou, Kagajizou, and Oushuku were first established in this study as S1S7, S2S6, S3S4, S3S6, S3S6 and S1S5, respectively. An extended elucidation of the S-genotype would contribute to a more efficient breeding program of the Japanese apricot.