High-Resolution Mapping of Two Broad-Spectrum Late Blight Resistance Genes from Two Wild Species of the Solanum circaeifolium Group

Abstract

High levels of resistance to Phytophthora infestans in Solanum are predominantly based on the gene-for-gene interaction. Identification of hitherto unknown R genes is essential for future pyramiding approaches. This could be achieved either through classic introgression breeding or through cisgenesis and could lead to sustainable control of late blight. Here, we report on the mapping of Rpi-cap1 and Rpi-qum1, two late blight R genes identified in the wild species Solanum capsicibaccatum and Solanum circaeifolium ssp. quimense, respectively, to very similar positions on the long arm of chromosome 11. Despite the difficulties encountered for marker development, a high-resolution genetic map with cleaved amplified polymorphic sequence markers was constructed. Furthermore, an R gene cluster-directed profiling approach led to the development of markers that closely linked to or co-segregated with the Rpi-cap1 gene. Both R genes are hypothesized to be homologous to the N gene, a toll-interleukin1 receptor-nucleotide-binding site-leucine-rich repeat domain type of R gene to tobacco mosaic virus from tobacco. To confirm this hypothesis, cloning of Rpi-cap1 and Rpi-qum1 should be pursued. Cloning would also be instrumental to facilitate the introduction of these valuable R genes into potato crops using cisgenic- and marker-assisted breeding approaches. © 2012 The Author(s).