A novel approach to locate Phytophthora infestans resistance genes on the potato genetic map

Abstract

Mapping resistance genes is usually accomplished by phenotyping a segregating population for the resistance trait and genotyping it using a large number of markers. Most resistance genes are of the NBS-LRR type, of which an increasing number is sequenced. These genes and their analogs (RGAs) are often organized in clusters. Clusters tend to be rather homogenous, viz. containing genes that show high sequence similarity with each other. From many of these clusters the map position is known. In this study we present and test a novel method to quickly identify to which cluster a new resistance gene belongs and to produce markers that can be used for introgression breeding. We used NBS profiling to identify markers in bulked DNA samples prepared from resistant and susceptible genotypes of small segregating populations. Markers co-segregating with resistance can be tested on individual plants and directly used for breeding. To identify the resistance gene cluster a gene belongs to, the fragments were sequenced and the sequences analyzed using bioinformatics tools. Putative map positions arising from this analysis were validated using markers mapped in the segregating population. The versatility of the approach is demonstrated with a number of populations derived from wild Solanum species segregating for P. infestans resistance. Newly identified P. infestans resistance genes originating from S. verrucosum, S. schenckii, and S. capsicibaccatum could be mapped to potato chromosomes 6, 4, and 11, respectively.

Differences in insect resistance between tomato species endemic to the Galapagos Islands

“…While some Solanum species are considered to be resistant, it is important to note that the level of resistance may vary between and within accessions of the same species. Next to resistance to whitefly [17], such inter- and intra-variation was also described, among others, in a screenings for white mold and late blight resistance in potato [17,24-26]. We have found resistance to whitefly in all S .…”

Polyploidy and Plant Breeding

“…The presence of specific pathogen effectors activates specific nucleotide binding LRR proteins that curtail pathogen spread. NBS profiling can be used to identify markers in bulked DNA samples from resistant and susceptible genotypes of small segregating populations (Jacobs et al 2010). DNA fragments are thereafter sequenced and their sequences analyzed by bioinformatics.…”

Agrotransformación y evaluación de la resistencia a Phytophthora infestansen Solanum tuberosum L. variedad Désirée

“…Asimismo, la búsqueda de nuevas fuentes de resistencia ha impulsado el uso de genes de la misma especie o de una familia cercana a la planta que se desee modificar (Storck et al 2012). Un ejemplo de ello son los genes R (genes de resistencia) de la familia de genes NB-LRR (Nucleotide binding and leucine-rich repeat), provenientes de la especie silvestre Solanum bulbocastanum (Collinge et al 2008, Jacobs et al 2010Pel et al 2009). Los genes R de S. bulbocastanum más Rev.…”