title: Related polymorphic F-box protein genes between haplotypes clustering in the BAC contig sequences around the S-RNase of Japanese pear.
abstract: Most fruit trees in the Rosaceae exhibit self-incompatibility, which is controlled by the pistil S gene, encoding a ribonuclease (S-RNase), and the pollen S gene at the S-locus. The pollen S in Prunus is an F-box protein gene (SLF/SFB) located near the S-RNase, but it has not been identified in Pyrus and Malus. In the Japanese pear, various F-box protein genes (PpSFBB(-α-γ)) linked to the S-RNase are proposed as the pollen S candidate. Two bacterial artificial chromosome (BAC) contigs around the S-RNase genes of Japanese pear were constructed, and 649 kb around S(4)-RNase and 378 kb around S(2)-RNase were sequenced. Six and 10 pollen-specific F-box protein genes (designated as PpSFBB(4-u1-u4, 4-d1-d2) and PpSFBB(2-u1-u5,) (2-d1-d5), respectively) were found, but PpSFBB(4-α-γ) and PpSFBB(2-γ) were absent. The PpSFBB(4) genes showed 66.2-93.1% amino acid identity with the PpSFBB(2) genes, which indicated clustering of related polymorphic F-box protein genes between haplotypes near the S-RNase of the Japanese pear. Phylogenetic analysis classified 36 F-box protein genes of Pyrus and Malus into two major groups (I and II), and also generated gene pairs of PpSFBB genes and PpSFBB/Malus F-box protein genes. Group I consisted of gene pairs with 76.3-94.9% identity, while group II consisted of gene pairs with higher identities (>92%) than group I. This grouping suggests that less polymorphic PpSFBB genes in group II are non-S pollen genes and that the pollen S candidates are included in the group I PpSFBB genes.
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657-8501, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Okada
authors.forename: Nozomi
authors.initials: N
authors.lastname: Tonaka
authors.forename: Tomio
authors.initials: T
authors.lastname: Taguchi
authors.forename: Takehiko
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sawamura
authors.forename: Tetsu
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takasaki-Yasuda
mesh_terms: D000595:Amino Acid Sequence; D022202:Chromosomes, Artificial, Bacterial; D044783:F-Box Proteins / Q000235:genetics*; D006239:Haplotypes; D027845:Malus / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D031989:Pyrus / Q000235:genetics*; D012260:Ribonucleases / Q000235:genetics*; D057945:Self-Fertilization / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D044783:F-Box Proteins; D012260:Ribonucleases; C112616:self-incompatibility ribonuclease S4