FISH mapping and molecular organization of the major repetitive sequences of tomato
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This paper presents a bird’s-eye view of the major repeats and chromatin types of tomato. Using fluorescence in-situ hybridization (FISH) with Cot-1, Cot-10 and Cot-100 DNA as probes we mapped repetitive sequences of different complexity on pachytene complements. Cot-100 was found to cover all heterochromatin regions, and could be used to identify repeat-rich clones in BAC filter hybridization. Next we established the chromosomal locations of the tandem and dispersed repeats with respect to euchromatin, nucleolar organizer regions (NORs), heterochromatin, and centromeres. The tomato genomic repeats TGRII and TGRIII appeared to be major components of the pericentromeres, whereas the newly discovered TGRIV repeat was found mainly in the structural centromeres. The highly methylated NOR of chromosome 2 is rich in [GACA]4, a microsatellite that also forms part of the pericentromeres, together with [GA]8, [GATA]4 and Ty1-copia. Based on the morphology of pachytene chromosomes and the distribution of repeats studied so far, we now propose six different chromatin classes for tomato: (1) euchromatin, (2) chromomeres, (3) distal heterochromatin and interstitial heterochromatic knobs, (4) pericentromere heterochromatin, (5) functional centromere heterochromatin and (6) nucleolar organizer region.
Key wordsCot fluorescence in-situ hybridization heterochromatin repetitive DNA repetitive sequences Solanum lycopersicum tomato
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- Chang S-B (2004) Cytogenetic and molecular studies on tomato chromosomes using diploid tomato and tomato monosomic additions in tetraploid potato. PhD thesis. University of Wageningen.Google Scholar
- De Jong JH, Zhong X-B, Fransz PF, Wennekes-van Eden J, Jacobsen E, Zabel P (2000) High resolution FISH reveals the molecular chromosomal organisation of repetitive sequences of individual tomato chromosomes. In: Olmo E, Redi CA, eds. Chromosomes Today. Switserland: Birkhäuser Verlag, 13: 267–275.Google Scholar
- Jurka J (2005) GYPSODE1: Gypsy-type element from wild potato. Repbase Reports 5: 246.Google Scholar
- Lapitan NLV, Ganal MW, Tanksley SD (1989) Somatic chromosome karyotype of tomato based on in situ hybridization of the TGRI satellite repeat. Genome 32: 992–998.Google Scholar
- Lapitan NLV, Ganal MW, Tanksley SK (1991) Organization of the 5S ribosomal RNA genes in the genome of tomato. Genome 34: 509–514.Google Scholar
- Peterson DG, Stack SM, Price HJ, Johnston JS (1995) Distribution of DNA in heterochromatin and euchromatin of Lycopersicon esculentum pachytene chromosomes. Tomato Genet Coop Rep 45: 35.Google Scholar
- Szinay D, Chang S-B, Khrustaleva L et al. (2008) High-resolution chromosome mapping of BACs using multi-colour FISH and pooled-BAC FISH as a backbone for sequencing tomato chromosome 6. Plant J (in press).Google Scholar
- Van Daelen RAJJ, Zabel P (1994) Preparation of high molecular weight plant DNA and analysis by pulsed field gel electrophoresis. In: Gelvin SB, Schilperoort RA, eds. Plant Molecular Biology Manual. Dordrecht: Kluwer Academic, H3: 1–21.Google Scholar
- Zabel P, Meyer D, van de Stolpe O et al. (1985) Towards the construction of artificial chromosomes for tomato. In: van Vloten-Doting L, Groot GSP, Hall TC, eds. Molecular Form and Function of the Plant Genome. New York: Plenum, 609–624.Google Scholar