A DArT marker-based linkage map for wild potato Solanum bulbocastanum facilitates structural comparisons between Solanum A and B genomes.
BACKGROUND
Wild potato Solanum bulbocastanum is a rich source of genetic resistance against a variety of pathogens. It belongs to a taxonomic group of wild potato species sexually isolated from cultivated potato. Consistent with genetic isolation, previous studies suggested that the genome of S. bulbocastanum (B genome) is structurally distinct from that of cultivated potato (A genome). However, the genome architecture of the species remains largely uncharacterized. The current study employed Diversity Arrays Technology (DArT) to generate a linkage map for S. bulbocastanum and compare its genome architecture with those of potato and tomato.


RESULTS
Two S. bulbocastanum parental linkage maps comprising 458 and 138 DArT markers were constructed. The integrated map comprises 401 non-redundant markers distributed across 12 linkage groups for a total length of 645 cM. Sequencing and alignment of DArT clones to reference physical maps from tomato and cultivated potato allowed direct comparison of marker orders between species. A total of nine genomic segments informative in comparative genomic studies were identified. Seven genome rearrangements correspond to previously-reported structural changes that have occurred since the speciation of tomato and potato. We also identified two S. bulbocastanum genomic regions that differ from cultivated potato, suggesting possible chromosome divergence between Solanum A and B genomes.


CONCLUSIONS
The linkage map developed here is the first medium density map of S. bulbocastanum and will assist mapping of agronomical genes and QTLs. The structural comparison with potato and tomato physical maps is the first genome wide comparison between Solanum A and B genomes and establishes a foundation for further investigation of B genome-specific structural chromosome rearrangements.
Department of Horticulture, University of Wisconsin, 1575 Linden Drive, Madison, WI, 53706, USA. iorizzo@wisc.edu.|Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall/1991 Upper Buford Circle, St. Paul, MN, 55108, USA. iorizzo@wisc.edu.|Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy. iorizzo@wisc.edu.
Massimo
M
Iorizzo
Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall/1991 Upper Buford Circle, St. Paul, MN, 55108, USA. gaoxx092@umn.edu.
Liangliang
L
Gao
Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall/1991 Upper Buford Circle, St. Paul, MN, 55108, USA. harpartap.s.mann@monsanto.com.
Harpartap
H
Mann
Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, London, United Kingdom. traini.alessandra@gmail.com.
Alessandra
A
Traini
Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy. chiusano@unina.it.
Maria Luisa
ML
Chiusano
Diversity Arrays Technology, Pty. Ltd., University of Canberra, Kirinari Street, Bruce, ACT 2617, Canberra, Australia. zej@diversityarrays.com.
Andrzej
A
Kilian
Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy. raversan@unina.it.
Riccardo
R
Aversano
Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy. carputo@unina.it.
Domenico
D
Carputo
Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall/1991 Upper Buford Circle, St. Paul, MN, 55108, USA. jbradeen@umn.edu.|Stakman-Borlaug Center for Sustainable Plant Health, 495 Borlaug Hall/1991 Upper Buford Circle, St. Paul, MN 55108, USA. jbradeen@umn.edu.
James M
JM
Bradeen
D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D032322:Solanum / Q000235:genetics*
D005819:Genetic Markers