Co-Authors:
Lieberman, M., Dept. of Plant Genetics and Breeding, Inst. of Plant Fld. and Garden Crops, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Segev, O., Dept. of Plant Genetics and Breeding, Inst. of Plant Fld. and Garden Crops, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Gilboa, N., Dept. of Plant Genetics and Breeding, Inst. of Plant Fld. and Garden Crops, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Lalazar, A., Dept. of Plant Genetics and Breeding, Inst. of Plant Fld. and Garden Crops, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Levin, I., Dept. of Plant Genetics and Breeding, Inst. of Plant Fld. and Garden Crops, Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Abstract:
A tomato EST sequence, highly homologous to the human and Arabidopsis thaliana UV-damaged DNA binding protein 1 (DDB1), was mapped to the centromeric region of the tomato chromosome 2. This region was previously shown to harbor the HP-1 gene, encoding the high pigment-1 (hp-1) and the high pigment-1 w (hp-1w) mutant phenotypes. Recent results also show that the A. thaliana DDB1 protein interacts both genetically and biochemically with the protein encoded by DEETIOLATED1, a gene carrying three tomato mutations that are in many respects isophenotypic to hp-1: high pigment-2 (hp-2), high pigment-2j (hp-2j) and dark green (dg). The entire coding region of the DDB1 gene was sequenced in an hp-1 mutant and its near-isogenic normal plant in the cv. Ailsa Craig background, and also in an hp-1w mutant and its isogenic normal plant in the GT breeding line background. Sequence analysis revealed a single A931-to-T931 base transversion in the coding sequence of the DDB1 gene in the hp-1 mutant plants. This transversion results in the substitution of the conserved asparagine at position 311 to a tyrosine residue. In the hp-1w mutant, on the other hand, a single G2392-to-A2392 transition was observed, resulting in the substitution of the conserved glutamic acid at position 798 to a lysine residue. The single nucleotide polymorphism that differentiates hp-1 mutant and normal plants in the cv. Ailsa Craig background was used to design a pyrosequencing genotyping system. Analysis of a resource F2 population segregating for the hp-1 mutation revealed a very strong linkage association between the DDB1 locus and the photomorphogenic response of the seedlings, measured as hypocotyl length (25<LOD score<26, R 2=62.8%). These resuits strongly support the hypothesis that DDB1 is the gene encoding the hp-1 and hp-1w mutant phenotypes. © Springer-Verlag 2004.