Detection of homologous resistance genes to the late blight in wild potatoes

The identification of resistance genes to late blight (Phytophthora infestans) is essential in potato (Solanum tuberosum) breeding programs to advance in obtaining resistant cultivars. The objective was to detect sequences homologous to the resistance genes (R1, R2, R3a, R8, Sto-448, Rpi-blb1, Rpi-blb2, and Rpi-ber1) to P. infestans in 23 accessions of 14 wild potato species (Solanum spp.) with different resistance levels through the amplification of molecular markers. Eight primers sets were used to amplify the molecular markers. No amplifications of resistance markers were observed in highly susceptible plants in the field (accession 631200 of S. chacoense, accession 653801 of S. berthaultii and accession 631201 of S. juzepzuckii), whereas in plants immune to the field, such as S. demissum (653770), amplification of six molecular markers was observed. The R3a marker did not amplify for any accession. Therefore, no apparent association between the number of markers amplified and the resistance category was found by Chi-square test. These results highlight the complexity of genetic resistance in the studied potato species. Future studies could evaluate the functionality of the homologous genes and detect other molecular markers of the resistance genes.