Structural and transcriptional analysis of the self-incompatibility locus of almond: Identification of a pollen-expressed F-box gene with haplotype-specific polymorphism

Koichiro Ushijima, Hidenori Sassa, Abhaya M. Dandekar, Thomas M. Gradziel, Ryutaro Tao, Hisashi Hirano

Research output: Contribution to journalArticle

353 Citations (Scopus)

Abstract

Gametophytic self-incompatibility in Rosaceae, Solanaceae, and Scrophulariaceae is controlled by the S locus, which consists of an S-RNase gene and an unidentified "pollen S" gene. An ∼70-kb segment of the S locus of the rosaceous species almond, the S haplotype-specific region containing the S-RNase gene, was sequenced completely. This region was found to contain two pollen-expressed F-box genes that are likely candidates for pollen S genes. One of them, named SFB (S haplotype-specific F-box protein), was expressed specifically in pollen and showed a high level of S haplotype-specific sequence polymorphism, comparable to that of the S-RNases. The other is unlikely to determine the S specificity of pollen because it showed little allelic sequence polymorphism and was expressed also in pistil. Three other S haplotypes were cloned, and the pollen-expressed genes were physically mapped. In all four cases, SFBs were linked physically to the S-RNase genes and were located at the S haplotype-specific region, where recombination is believed to be suppressed, suggesting that the two genes are inherited as a unit. These features are consistent with the hypothesis that SFB is the pollen S gene. This hypothesis predicts the involvement of the ubiquitin/26S proteasome proteolytic pathway in the RNase-based gametophytic self-incompatibility system.

Original languageEnglish
Pages (from-to)771-781
Number of pages11
JournalPlant Cell
Volume15
Issue number3
DOIs
Publication statusPublished - Mar 1 2003
Externally publishedYes

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ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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