Transcript and Sequence Analysis of S-RNases in Self-Compatible Tetraploid Chinese Cherry (Prunus pseudocerasus L.)

Chinese cherry (Prunus pseudocerasus L.) is an allotetraploid species and exhibits natural self-compatibility. However, the full-length cDNA sequences, functional analysis and the transcripts of S-RNase alleles in Chinese cherry cultivars are not known. In the two cultivars Taixiaohongying and Laiyang Short Cherry with S1S2S3S4 genotypes, two S-RNases were transcribed in Northern blotting, and the two full-length cDNAs of S-RNase were cloned and analyzed. As the result, the transcribed S-RNases were S1-RNase and S2-RNase. The two complete cDNA sequences of S1-RNase and S2-RNase were registered as EU073938 and EU073939, respectively, and had characteristic structure of rosaceous S-RNases based on their sequences indicating that they had normal function for S-RNase in the style. The S3-RNase and S4-RNase were not transcribed in the style and were nonfunctional for S-RNase, so S3m and S4m could be used to represent the nonfunctional S3-RNase and S4-RNase. The phylogenetic analysis implied that the S-RNases of Prunus, including Chinese cherry, had lower intra-specific similarity and diverged earlier than the divergence of species in Prunus.