Utilizing 'Omics' technologies to identify and prioritize novel sources of resistance to the oomycete pathogen Phytophthora infestans in potato germplasm collections

We have established and validated diagnostic RenSeq as a tool to quickly assess if resistant plants contain already characterized NB-LRR genes. Diagnostic RenSeq in resistant S. okadae accessions 7129, 7625, 3762 and a bulk of 20 resistant progeny confirmed the presence of full-length Rpi-vnt1.1 under stringent mapping conditions and corroborated Avr-vnt1 recognition and allele mining results in the accessions 7129 and 7625. In contrast, susceptible S. okadae accession 3761 and a bulk of 20 susceptible progeny lacked sequence homology in the 5’ end compared to the functional Rpi-vnt1.1 gene. Further evaluation of S. okadae accessions with late blight isolates that have a broad spectrum of virulence, has demonstrated that, although S. okadae accessions 7129, 7625 and 7629 contain functional Rpi-vnt1.1, they also carry a novel resistance gene. We have provided evidence that diagnostic RenSeq is a valuable tool to quickly establish if characterized resistance genes are present in wild Solanum species and propose its use for identifying orthologs with high sequence similarity and to aid R gene pyramiding and breeding.