Abstract
Aphids cause serious physical and economic damage to most major crops throughout the world, and there is a pressing requirement to isolate genes conferring aphid resistance. The Sd-1 locus in Malus spp. (apple) confers resistance against the rosy leaf-curling aphid (Dysaphis devecta Wlk.), and was recently positioned within a 1.3-cM region on linkage group 7, flanked by molecular markers. These markers were used as a basis for development of a BAC contig spanning the locus, together with adapter-mediated amplification of flanking sequences to obtain BAC insert-end sequences, and fingerprinting of BAC clones. Approximately 800 kb of the Sd-1 genomic region was covered by 19 overlapping BACs, with an average insert size of 75-150 kb. The physical-genetic distance ratio was estimated at 460 kb/cM, although the distribution of recombination events was irregular with respect to estimated physical distance. Recombinant analysis and development of new markers allowed Sd-1 to be positioned within an interval of approximately 180 kb located on either of two overlapping BACs. From one of these, an insert end sequence showed a significant degree of similarity to nucleotide binding site-leucine rich repeat (NBS-LRR) resistance genes. Fluorescent in situ hybridization (FISH) of BAC clones within the contig enabled positioning and orientation of the locus within a euchromatic region, very close to the telomere of linkage group 7.
Original language | English |
---|---|
Pages (from-to) | 939-945 |
Number of pages | 7 |
Journal | Genome Biology |
Volume | 45 |
Issue number | 5 |
Publication status | Published - Oct 2002 |
Keywords
- Animals
- Aphids
- Base Sequence
- Chromosome Mapping
- Chromosomes, Artificial, Bacterial
- Chromosomes, Plant
- DNA Primers
- Genes, Plant
- Genetic Linkage
- Genetic Markers
- In Situ Hybridization, Fluorescence
- Malus
- Plant Diseases
- Telomere
- Journal Article
- Research Support, Non-U.S. Gov't