Background
Potato virus Y (PVY) is among the economically most damaging viral pathogen in production of potato (Solanum tuberosum) worldwide.The gene Rysto derived from the wild potato relative Solanum stoloniferum confers extreme resistance to PVY.
Results
The presence of Rysto and diversity of it was investigated in wild relatives of potato (298 genotypes representing 29 accessions of 26 tuber-bearing Solanum species) using PacBio amplicon sequencing.A total of 55 unique Rysto-like sequences were identified in 72 genotypes representing 12 accessions of ten Solanum species and six resistant controls (potato cultivars Alicja, Bzura, Hinga, Nimfy, White Lady and breeding line PW363).The 55 Rysto-like sequences showed 89.87 to 99.98% nucleotide identity to the Rysto reference gene, and these encoded in total 45 unique protein sequences.While Rysto-like26 identified in Alicja, Bzura White Lady and Rysto-like16 in PW363 encode a protein identical to the Rysto reference, the remaining 44 predicted Rysto-like proteins were 65.93 to 99.92% identical to the reference.Higher levels of diversity of the Rysto-like sequences were found in the wild relatives of potato than in the resistant control cultivars.The TIR and NB-ARC domains were the most conserved within the Rysto-like proteins, while the LRR and C-JID domains were more variable.Several of the tested Solanum species, including S.
antipoviczii and S.hougasii, showed resistance to PVY.This study demonstrated Hyoscyamus niger, a Solanaceae species distantly related to Solanum, as a host of PVY.
Conclusions
The new Rysto-like variants, as well as the PVY resistant potato genotypes identified in this study, could be potential resistance gene sources against PVY in potato breeding.Identification of H.
niger as a host for PVY is important for cultivation of this plant, studies on the PVY management, its ecology, and migrations.The amplicon sequencing based on PacBio SMRT technology and the following data analysis pipeline described in our work may be applied to obtain the nucleotide sequences and analyze any full-length genes from any, even polyploid, organisms..
