Unlocking the Genetic Potential of Solanum bulbocastanum (SB22, Selection 22): A Valuable Resource for Enhancing Disease Resistance in Commercial Potato Cultivars

Cultivated potatoes are susceptible to a host of diseases caused by various pathogens. Wild relatives of potatoes are used in breeding programs as sources of resistance introgressed into cultivated potatoes. The wild potato Solanum bulbocastanum is an essential source of resistance to Columbia root knot nematode (CRKN) and late blight. We present the initial chromosome-level assembly of SB22, produced using PacBio long reads and Dovetail Hi-C scaffolding. The final assembly size was 655.3 Mb. Using the BRAKER pipeline, 43,280 gene models were predicted, with a BUSCO completeness of about 90.3%. Repeat elements represented 63.8% of the genome, with LTR elements being the most abundant. DRAGO3 predicted 2,310 disease resistance-like genes across the 12 chromosomes of SB22; the MEME suite was used to identify their amino acid motifs. Putative candidate genes contributing to CRKN resistance were mapped on chromosome 11 of SB22. The SB22 draft genome is a valuable genomic resource for potato breeding programs.