Molecular characterization of the progeny of Solanum etuberosum identifies a genomic region associated with resistance to potato leafroll virus

Abstract

Potato leafroll virus (PLRV; Genus Polerovirus; Family Luteoviridae) is one of the most important virus pathogens of potato worldwide and breeders are looking for new sources of resistance. Solanum etuberosum Lindl., a wild potato species native to Chile, was identified as having resistances to PLRV, potato virus Y, potato virus X, and green peach aphid. Barriers to sexual hybridization between S. etuberosum and cultivated potato were overcome through somatic hybridization. Resistance to PLRV has been identified in the BC1, BC2 and BC3 progeny of the somatic hybrids of S. etuberosum (+) S. tuberosum haploid × S. berthaultii Hawkes. In this study, RFLP markers previously mapped in potato, tomato or populations derived from S. palustre (syn S. brevidens) × S. etuberosum and simple sequence repeat (SSR) markers developed from tomato and potato EST sequences were used to characterize S. etuberosum genomic regions associated with resistance to PLRV. The RFLP marker TG443 from tomato linkage group 4 was found to segregate with PLRV resistance. This chromosome region has not previously been associated with PLRV resistance and therefore suggests a unique source of resistance. Synteny groups of molecular markers were constructed using information from published genetic linkage maps of potato, tomato and S. palustre (syn. S. brevidens) × S. etuberosum. Analysis of synteny group transmission over generations confirmed the sequential loss of S. etuberosum chromosomes with each backcross to potato. Marker analyses provided evidence of recombination between the potato and S. etuberosum genomes and/or fragmentation of the S. etuberosum chromosomes.