Deletion of a 236 kb region around S 4-RNase in a stylar-part mutant S 4sm-haplotype of Japanese pear.
Japanese pear (Pyrus pyrifolia Nakai) has a gametophytic self-incompatibility (GSI) mechanism controlled by a single S-locus with multiple S-haplotypes, each of which contains separate genes that determine the allelic identity of pistil and pollen. The pistil S gene is the S-ribonuclease (S-RNase) gene, whereas good candidates for the pollen S gene are the F-box protein genes. A self-compatible (SC) cultivar, 'Osa-Nijisseiki', which is a bud mutant of 'Nijisseiki' (S (2) S (4)), has a stylar-part mutant S(4)sm-haplotype, which lacks the S (4)-RNase gene but retains the pollen S gene. To delineate the deletion breakpoint in the S(4)sm-haplotype, we constructed a bacterial artificial chromosome (BAC) library from an S (4)-homozygote, and assembled a BAC contig of 570 kb around the S (4)-RNase. Genomic PCR of DNA from S (4)- and S(4)sm-homozygotes and the DNA sequence of the BAC contig allowed the identification of a deletion of 236 kb spanning from 48 kb upstream to 188 kb downstream of S (4)-RNase. The S(4)sm-haplotype lacks 34 predicted open reading frames (ORFs) including the S (4)-RNase and a pollen-specific F-box protein gene (termed as S (4) F-box0). Genomic PCR with a primer pair designed from the deletion junctions yielded a product specific for the S(4)sm-haplotype. The product could be useful as a maker for early selection of SC cultivars harboring the S(4)sm-haplotype.
Okada
Kazuma
K
Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657-8501, Japan.
Tonaka
Nozomi
N
Moriya
Yuki
Y
Norioka
Naoko
N
Sawamura
Yutaka
Y
Matsumoto
Tatsuya
T
Nakanishi
Tetsu
T
Takasaki-Yasuda
Takeshi
T
D001483:Base Sequence; D016386:Chromosome Walking; D032461:Chromosomes, Plant / Q000235:genetics*; D004722:Endoribonucleases / Q000235:genetics*; D035264:Flowers / Q000201:enzymology / Q000235:genetics; D007564:Japan; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics; D011058:Pollen / Q000201:enzymology / Q000235:genetics; D031989:Pyrus / Q000201:enzymology* / Q000235:genetics*
D010940:Plant Proteins; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease