Molecular Genetics and Genomics

, Volume 269, Issue 5, pp 603–611

Concomitant reiterative BAC walking and fine genetic mapping enable physical map development for the broad-spectrum late blight resistance region, RB

Authors

  • J. M. Bradeen
    • Department of Plant PathologyUniversity of Wisconsin
    • Department of Plant PathologyUniversity of Minnesota
  • S. K. Naess
    • USDA-ARS, Department of Plant PathologyUniversity of Wisconsin
    • Centre de Recherche Les Buissons
  • J. Song
    • Department of HorticultureUniversity of Wisconsin
  • G. T. Haberlach
    • USDA-ARS, Department of Plant PathologyUniversity of Wisconsin
  • S. M. Wielgus
    • Department of Plant PathologyUniversity of Wisconsin
  • C. R. Buell
    • The Institute for Genomic Research
    • Department of HorticultureUniversity of Wisconsin
    • USDA-ARS, Department of Plant PathologyUniversity of Wisconsin
Original Paper

DOI: 10.1007/s00438-003-0865-8

Cite this article as:
Bradeen, J.M., Naess, S.K., Song, J. et al. Mol Gen Genomics (2003) 269: 603. doi:10.1007/s00438-003-0865-8

Abstract

The wild potato species Solanum bulbocastanum is a source of genes for potent late blight resistance. We previously mapped resistance to a single region of the S. bulbocastanum chromosome 8 and named the region RB (for "Resistance from S. Bulbocastanum "). We now report physical mapping and contig construction for the RB region via a novel reiterative method of BAC walking and concomitant fine genetic mapping. BAC walking was initiated using RFLP markers previously shown to be associated with late blight resistance. Subcontig extension was accomplished using new probes developed from BAC ends. Significantly, BAC end and partial BAC sequences were also used to develop PCR-based markers to enhance map resolution in the RB region. As they were developed from BAC clones of known position relative to RB, our PCR-based markers are known a priori to be physically closer to the resistance region. These markers allowed the efficient screening of large numbers of segregating progeny at the cotyledon stage, and permitted us to assign the resistance phenotype to a region of approximately 55 kb. Our markers also directed BAC walking efforts away from regions distantly related to RB in favor of the 55-kb region. Because the S. bulbocastanum genotype used in BAC library construction is heterozygous for RB (RB/rb), codominant PCR-based markers, originally developed for fine-scale mapping, were also used to determine homolog origins for individual BAC clones. Ultimately, BAC contigs were constructed for the RB region from both resistant (RB) and susceptible (rb) homologs.

Keywords

Solanum bulbocastanumGeneral resistanceReiterative mappingCleaved Amplified Polymorphic Sequences (CAPS)

Copyright information

© Springer-Verlag 2003