Late blight resistance in wild potato species—Resources for future potato (Solanum tuberosum) breeding

Abstract

Late blight remains the most devastating disease in potato cultivation. The best protection against this disease could be achieved by durably resistant cultivars, but these do not exist at present. To advance resistance breeding, the search for resistant wild potato species and the characterization of their resistance is important. There have recently been a number of new developments in this area. For this reason, all wild potato species known to the authors in which resistance has been found to date are listed in this article with their respective genes and QTL. Lastly, an overview is given, how these new resistance sources can be used for future resistance breeding.

Diversity of Late Blight Resistance Genes in the VIR Potato Collection

“…As anticipated, the most prominent in the Petota set under study were the patterns of SCAR markers recognizing the Rpi-R1 , Rpi-2 , Rpi-R3a , Rpi-3b , and Rpi-R8 genes, which were initially found in S. demissum [ 4 , 6 , 9 , 14 ]; below we will call these genes demissoid. In S. demissum , the marker frequencies for these genes varied from 0.18 (Rpi-R3a-1380) and 0.17 (Rpi-R8-1258) to 0.9 (Rpi-R3b-378).…”

“…A considerable part of potato genomes is represented by the genes that determine resistance to numerous diseases and pests. Among them, the dominant Rpi genes apparently evolved from the NB-LRR predecessor structures (protogenes) when the Solanum species were adjusting to the particular habitats in both American continents and co-evolving with the local repertoires of P. infestans [ 9 , 80 , 81 , 82 , 83 ].…”

“…Here, as well as worldwide, late blight (LB) caused by the oomycete Phytophthora infestans (Mont.) de Bary is a major threat to potato crops, and the dominant race-specific genes for resistance to P. infestans ( Rpi genes) have been most vigorously searched for by geneticists and explored by breeders [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. These genes are found in wild, primitive, and cultivated tuber-bearing species of Solanum L. (section Petota Dumort.…”

“…and to the South American series Tuberosa (Rydb.) Hawkes [ 2 , 5 , 6 , 9 , 10 , 11 , 12 , 13 , 14 ]. Outside two American continents and beyond the section Petota , we find the homologous Rpi genes in such widespread species as S. americanum Mill.…”

Converting Hybrid Potato Breeding Science into Practice

“…Application of SNP markers makes trait introgression and monitoring straight forward and cost effective. For potato, numerous molecular markers have been published, focusing mainly on pathogen resistances, e.g., Late Blight [ 40 ], Potato Cyst Nematode [ 41 ], and Wart disease [ 42 ]. However, due to potato’s large genetic variation it is not easy to identify SNPs that are generally applicable.…”