FISH to meiotic pachytene chromosomes of tomato locates the root-knot nematode resistance gene Mi-1 and the acid phosphatase gene Aps-1 near the junction of euchromatin and pericentromeric heterochromatin of chromosome arms 6S and 6L, respectively

• Published in: Theoretical and applied genetics Vol. 98; no. 3-4; pp. 365 - 370
• Main Authors: ZHONG, X.-B, BODEAU, J, FRANSZ, P. F, WILLIAMSON, V. M, VAN KAMMEN, A, DE JONG, J. H, ZABEL, P
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-03-1999; Berlin Springer Nature B.V
• Subjects: Acids; Biological and medical sciences; Chromosome banding; Chromosome mapping; Chromosomes; Classical genetics, quantitative genetics, hybrids; Cloning; EPS; Fundamental and applied biological sciences. Psychology; Genetic aspects; Genetics of eukaryotes. Biological and molecular evolution; Laboratorium voor Erfelijkheidsleer; Laboratorium voor Moleculaire biologie; Laboratory of Genetics; Laboratory of Molecular Biology; Lycopersicon esculentum; Nematoda; Nematodes; Phosphatase; Plant genetics; Plant immunology; Pteridophyta, spermatophyta; Tomatoes; Vegetals; United States; United States > US; Texas; Genetic mapping; Enzyme; Meloidogyne; Phosphoric monoester hydrolases; Chromosome 6; Esterases; Vegetable crop; Dicotyledones; Angiospermae; Lycopersicon esculentum; Helmintha; Hydrolases; Pest resistance; Nemathelminthia; Spermatophyta; Solanaceae; Invertebrata; Nematoda; Acid phosphatase; Physical map
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s001220051081

The root-knot nematode resistance gene Mi-1 in tomato has long been thought to be located in the pericentromeric heterochromatin region of the long arm of chromosome 6 because of its very tight genetic linkage (approx. 1cM) to the markers Aps-1 (Acid phosphatase 1) and yv (yellow virescent). Using Mi-BAC clones and an Aps-1 YAC clone in fluorescence in situ hybridisation (FISH) to pachytene chromosomes we now provide direct physical evidence showing that Mi-1 is located at the border of the euchromatin and heterochromatin regions in the short arm (6S) and Aps-1 in the pericentromeric heterochromatin of the long arm (6L) close to the euchromatin. Taking into account both the estimated DNA content of hetero-and euchromatin regions and the compactness of the tomato chromosomes at pachytene (2 Mb/µm), our data suggest that Mi-1 and Aps-1 are at least 40 Mb apart, a base pair-to-centiMorgan relationship that is more than 50-fold higher than the average value of 750 kb/cM of the tomato genome. An integrated cytogenetic-molecular map of chromosome 6 is presented that provides a framework for physical mapping.