Cloning and characterization of genomic DNA sequences of four self-incompatibility alleles in sweet cherry ( Prunus avium L.).
Gametophytic self-incompatibility (GSI) in sweet cherry is determined by a locus S with multiple alleles. In the style, the S-locus codifies for an allele-specific ribonuclease ( S-RNase) that is involved in the rejection of pollen that carries the same S allele. In this work we report the cloning and genomic DNA sequence analysis including the 5' flanking regions of four S-RNases of sweet cherry ( Prunus avium L., Rosaceae). DNA from the cultivars Ferrovia, Pico Colorado, Taleguera Brillante and Vittoria was amplified through PCR using primers designed in the conserved sequences of sweet cherry S-RNases. Two alleles were amplified for each cultivar and three of them correspond to three new S-alleles named S23, S24 and S25 present in 'Pico Colorado', 'Vittoria' and 'Taleguera Brillante' respectively. To confirm the identity of the amplified fragments, the genomic DNA of these three putative S-RNases and the allele S12 amplified in the cultivar Ferrovia were cloned and sequenced. The nucleotide and deduced amino-acid sequences obtained contained the structural features of rosaceous S-RNases. The isolation of the 5'-flanking sequences of these four S-RNases revealed a conserved putative TATA box and high similarity among them downstream from that sequence. However, similarity was low compared with the 5'-flanking regions of S-RNases from the Maloideae. S6- and S24-RNase sequences are highly similar, and most amino-acid substitutions among these two RNases occur outside the rosaceous hypervariable region (RHV), but within another highly variable region. The confirmation of the different specificity of these two S-RNases would help elucidate which regions of the S-RNase sequences play a role in S-pollen specific recognition.
Wünsch
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Unidad de Fruticultura, S.I.A.-D.G.A., Campus de Aula Dei, Apdo. 727, 50080, Zaragoza, Spain.
Hormaza
J I
JI
D020121:5' Untranslated Regions / Q000235:genetics; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant / Q000235:genetics*; D008969:Molecular Sequence Data; D027861:Prunus / Q000201:enzymology / Q000235:genetics*; D012260:Ribonucleases / Q000737:chemistry* / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D020121:5' Untranslated Regions; D018076:DNA, Complementary; D018744:DNA, Plant; D012260:Ribonucleases