Mapping, stacking and characterization of a novel resistance haplotype against GpaV vrn -virulent Globodera pallida derived from wild potato relative Solanum brevicaule

Potato production is threatened by pests and pathogens. Among the most harmful are the potato cyst nematodes (PCN), including Globodera pallida . The major control measures are potato cultivars harbouring resistance genes. However, virulent nematode populations are breaking through the most broadly applied resistance genes, and therefore novel resistance genes are required to keep control of G. pallida . In this study we map a resistance locus in wild potato relative Solanum brevicaule to the bottom of chromosome 11 (42.83 - 42.85 Mb) using a k-mer based bulked segregant analysis and name the resistant haplotype GpaXI brc . The presence of the GpaXI brc marker in the potato genome significantly increases resistance against a GpaV vrn -virulent G. pallida population (AMPOP01). Furthermore, the GpaXI brc haplotype was stacked with three other resistance haplotypes: GpaXI tar , GpaV vrn , and GpaIX vrn . Stacking of the novel GpaXI brc haplotype to these other resistance haplotypes resulted in a significant increase in resistance. The largest effect was seen in combinations with 'major' resistance haplotypes GpaV vrn + GpaIX vrn and GpaXI tar + GpaXI brc . To determine whether we are dealing with a novel allele, the resistance mechanism underlying the GpaXI brc haplotype was described after performing an in vitro bioassay. The resistance mechanism was different from GpaXI spl as described in literature, which is also localized at the bottom of chromosome 11. Therefore, we conclude that we found a novel resistance allele originating from S. brevicaule .