Identification and characterization of S-RNase genes and S-genotypes in Prunus and Malus species

Chao Gu, Lu Wang, Schuyler S. Korban, Yuepeng Han

Research output: Contribution to journalArticlepeer-review


Most Rosaceae fruit trees such as Prunus and Malus species exhibit gametophytic self-incompatibility that is genetically controlled by the S-locus. In turn, the S-locus contains at least two tightly-linked S-determinant genes, a pistil S-RNase and a pollen SFB. In this study, S-genotypes of 120 cultivated and wild Prunus accessions (peach) and seven wild Malus accessions (crabapple) have been characterized. Among cultivated Prunus genotypes, four S-RNase alleles, designated S1, S2, S3, and S4, have been identified, and they share typical structural features of S-RNases from all other self-incompatible Prunus species. Four S-genotypes, S1S2, S1S3, S1S4, and S2S2, were identified in peach cultivars, while only one S-genotype S1S2 for wild Prunus species. The S1S2 genotype is predominant in peach cultivars, accounting for 58.3% of all evaluated accessions. Similarly, four SFB alleles were identified in peach cultivars and wild accessions. However, all the four SFB alleles encode truncated proteins due to a frame-shift mutation, resulting in loss of hyper-variable and/or variable regions. For Malus species, a total of 14 S-RNase alleles are identified, and of those, two alleles encode truncated proteins. Overall, the genetic variation of both S-RNase and SFB genes in peach is significantly lower than that of S-RNase and SFB genes in self-incompatible Malus and/or Prunus species. The relationship between the genetic variation of SFB genes and the diversification of S-RNase genes in Rosaceae is also discussed.

Original languageEnglish (US)
Pages (from-to)213-225
Number of pages13
JournalCanadian Journal of Plant Science
Issue number2
StatePublished - Mar 4 2015
Externally publishedYes


  • Malus
  • Pollen
  • Prunus
  • S-RNase
  • S-determinant
  • S-genotypes
  • Self-incompatibility

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science
  • Horticulture


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