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

Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
The Plant Cell (Impact Factor: 9.34). 04/2003; 15(3):771-81.
Source: PubMed


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 approximately 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.

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Available from: Ryutaro Tao, May 20, 2015
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    • "Webb). In these species, the pistil-S determinant is a single ribonuclease (S-RNase) and the pollen-S determinant is a protein encoded by a single S haplotype-specific F-box gene (SFB) (Entani et al. 2003, Ushijima et al. 2003, Yamane et al. 2003). It has been hypothesized that a general inactivation mechanism detoxifies non-self S-RNases, whereas SFB protects self S-RNase (Sonneveld et al. 2005). "
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    ABSTRACT: Gametophytic self-incompatibility in Japanese pear (Pyrus pyrifolia Nakai) is controlled by the single, multi-allelic S-locus. Information about the S-genotypes is important for breeding and the selection of pollen donors for fruit production. Rapid and reliable S-genotype identification system is necessary for efficient breeding of new cultivars in Japanese pear. We designed S allele-specific PCR primer pairs for ten previously reported S-RNase alleles (S (1)-S (9) and S (k)) as simple and reliable method. Specific nucleotide sequences were chosen to design the primers to amplify fragments of only the corresponding S alleles. The developed primer pairs were evaluated by using homozygous S-genotypes (S (1)/S (1)-S (9)/S (9) and S (4sm)/S (4sm)) and 14 major Japanese pear cultivars, and found that S allele-specific primer pairs can identify S-genotypes effectively. The S allele-specific primer pairs developed in this study will be useful for efficient S-genotyping and for marker-assisted selection in Japanese pear breeding programs.
    Breeding Science 06/2015; 65(3):208-15. DOI:10.1270/jsbbs.65.208 · 2.13 Impact Factor
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    • "avium L.; Ushijima et al., 2004) and plum (P. mume Siebold & Zucc.; Ushijima et al., 2003; Yamane et al., 2003). Later, a transformation experiment showed that an F-box protein gene, called SLF for the S locus F-box gene, was the pollen S in Putunia inflata (Solanaceae) (Sijacic et al., 2004). "

    Acta horticulturae 01/2015; DOI:10.17660/ActaHortic.2015.1065.161
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    • ") or SFB (S haplotype-specific F-box protein) (Ushijima et al. 2003) that is predicted to recognize self S-RNase, whereas in the Pyrinae, there are multiple F-box proteins called SFBB (S locus F-box brothers) (Sassa et al. 2007; Minamikawa et al. 2010) that are predicted to collaborate in recognizing non-self S-RNase (Kakui et al. 2011; Saito et al. 2012). In either case, these plants require cross pollination with other cultivars to set fruit. "
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    ABSTRACT: Radiation mutant 415-1, which is the first known diploid pollen-part self-compatible mutant of pears (Pyrus spp.), has a decreased ability to produce pollen. To determine whether the self-compatibility trait is associated with this defect, we directly analyzed the genotypes of individual pollen grains by using polymerase chain reaction amplification of DNA from single pollen grains. We isolated single pollen grains from 415-1 and succeeded in genotyping the S-RNase gene and three simple sequence repeat (SSR) markers in linkage group 17. Out of 173 individual pollen grains, 28 (16 %) were S-heteroallelic. These pollen grains had two alleles each of the S-RNase gene and of two linked SSR loci, all on a duplicated chromosomal segment, but only one allele of a non-duplicated locus farther away on the same chromosome. The segregation ratio of each marker in the pollen from 415-1 was approximately the same as that observed in outcross progeny. This suggests that the decrease in frequency of pollen with the duplicated S-haplotype occurred during meiosis or pollen formation, but that the probability of fertilization by S-heteroallelic pollen is equal to that of single-allelic pollen. However, the partial sterility in 415-1 can also be attributed to one or more unidentified lethal mutations unlinked to the duplicated segment encompassing the S-haplotype. Single-pollen genotyping can be used in a variety of applications in genetic research because in cases where all pollen genotypes are proportionately represented in the progeny, segregation ratios can be obtained without producing the next generation.
    Euphytica 11/2014; 200(2):297-304. DOI:10.1007/s10681-014-1168-3 · 1.39 Impact Factor
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