S locus F-box brothers: Multiple and pollen-specific F-box genes with S haplotype-specific polymorphisms in apple and Japanese pear

Hidenori Sassa, Hiroyuki Kakui, Mayu Miyamoto, Yusuke Suzuki, Toshio Hanada, Koichiro Ushijima, Makoto Kusaba, Hisashi Hirano, Takato Koba

Research output: Contribution to journalArticle

132 Citations (Scopus)

Abstract

Although recent findings suggest that the F-box genes SFB/SLF control pollen-part S specificity in the S-RNase-based gametophytic self-incompatibility (GSI) system, how these genes operate in the system is unknown, and functional variation of pollen S genes in different species has been reported. Here, we analyzed the S locus of two species of Maloideae: apple (Malus domestica) and Japanese pear (Pyrus pyrifolia). The sequencing of a 317-kb region of the apple S9 haplotype revealed two similar F-box genes. Homologous sequences were isolated from different haplotypes of apple and Japanese pear, and they were found to be polymorphic genes derived from the S locus. Since each S haplotype contains two or three related genes, the genes were named SFBB for S locus F-box brothers. The SFBB genes are specifically expressed in pollen, and variable regions of the SFBB genes are under positive selection. In a style-specific mutant S haplotype of Japanese pear, the SFBB genes are retained. Apart from their multiplicity, SFBB genes meet the expected characteristics of pollen S. The unique multiplicity of SFBB genes as the pollen S candidate is discussed in the context of mechanistic variation in the S-RNase-based GSI system.

Original languageEnglish
Pages (from-to)1869-1881
Number of pages13
JournalGenetics
Volume175
Issue number4
DOIs
Publication statusPublished - Apr 2007

ASJC Scopus subject areas

  • Genetics

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