Molecular Diagnostics for Complex Pest and Disease Resistance and Tuber Quality Traits: Concept, Achievements and Perspectives
Gebhardt, C. ; Urbany, C. ; Li, L. ; Stich, B. ; Caldas Paulo, M.J. ; Draffehn, A. ; Ballvora, A. - \ 2011
Potato Research 54 (2011)4. - ISSN 0014-3065 - p. 313 - 318.
late blight - potato - organization - association - genome - gene
We summarize the concept of molecular diagnostic of complex traits related to pest and disease resistance and to tuber quality of potato, and describe recent achievements and perspectives. Many potato characteristics are controlled by multiple genetic and environmental factors. Knowing the genes and their allelic variants that underlay these characteristics allows developing molecular diagnostic tools to select for improved potato cultivars. Diagnostic DNA-based markers can be used to identify superior genotypes (precision breeding). Diagnostic markers can be identified by combining quantitative trait locus mapping, candidate gene mapping and association mapping using functional and positional candidate genes as markers. This approach was successfully used to identify loci, which contribute to the natural variation of important agronomic traits, including resistance against root cyst nematodes, late blight and wart disease and tuber quality (resistance to bruising and chip colour). In the future, whole genome association mapping based on single-nucleotide polymorphism genotyping methods in combination with the annotated potato genome sequence will allow identifying additional genes and gene variants controlling agronomic performance in potato. Prerequisites are accurate phenotyping under field conditions of advanced breeding materials, cost-effective and reliable genome-wide genotyping methods, and user-friendly software tools allowing to extract knowledge from massive quantities of data. This will further facilitate molecular diagnosis, selection and combination of superior alleles in potato-breeding programmes.
Comparison of the chromosome maps around a resistance hot spot on chromosome 5 of potato and tomato using BAC-FISH painting
Achenbach, U.C. ; Tang, X.M. ; Ballvora, A. ; Jong, H. de; Gebhardt, C. - \ 2010
Genome 53 (2010)2. - ISSN 0831-2796 - p. 103 - 110.
in-situ hybridization - zea-mays l. - broad-spectrum resistance - globodera-pallida - phytophthora-infestans - pachytene chromosomes - gene-cluster - metaphase chromosomes - arabidopsis-thaliana - solanum-spegazzinii
Potato chromosome 5 harbours numerous genes for important qualitative and quantitative traits, such as resistance to the root cyst nematode Globodera pallida and the late blight fungus, Phytophthora infestans. The genes make up part of a “hot spot” for resistances to various pathogens covering a genetic map length of 3 cM between markers GP21 and GP179. We established the physical size and position of this region on chromosome 5 in potato and tomato using fluorescence in situ hybridization (FISH) on pachytene chromosomes. Five potato bacterial artificial chromosome (BAC) clones with the genetically anchored markers GP21, R1-contig (proximal end), CosA, GP179, and StPto were selected, labeled with different fluorophores, and hybridized in a five-colour FISH experiment. Our results showed the location of the BAC clones in the middle of the long arm of chromosome 5 in both potato and tomato. Based on chromosome measurements, we estimate the physical size of the GP21–GP179 interval at 0.85 Mb and 1.2 Mb in potato and tomato, respectively. The GP21–GP179 interval is part of a genome segment known to have inverted map positions between potato and tomato.