Identification and characterisation of a melon genomic region containing a resistance gene cluster from a constructed BAC library. Microcolinearity between Cucumis melo and Arabidopsis thaliana

A bacterial artificial chromosome (BAC) library from the dihaploid melon line `PIT92' was constructed with a 6 times coverage of the haploid melon genome. A contig of four BACs around the MRGH63 resistance gene homologue fragment was created. The complete sequence of a 117-kb BAC clone allowed to determine two clearly defined regions, the first one containing a cluster of three resistance gene homologues. Separated by a retrotransposon, that contains large long terminal repeats, the second region presents a group of genes with a conserved distribution in two regions of the Arabidopsis genome. The detailed analysis of this region provides a description of the gene structure and the presence of repetitive sequences in a defined fragment of the genome of Cucumis melo.Funds for this project were provided by grant2FD97-0286-(02-01) from the Spanish ‘Comisión Interdepartamental de Ciencia y Tecnología’ (CICYT) and grant 2000FI-00316 to Hans van Leeuwen from the Catalan ‘Comisión Interdepartamental de Recerca i Tecnología’ (CIRIT).Peer reviewe