Identification of a candidate gene for resistance to root‐knot nematode in a wild peach and screening of its polymorphisms

Root‐knot nematode disease, caused by M eloidogyne species, is an important soil‐borne disease of peach ( P runus persica L.) worldwide. To identify a major locus of genetic resistance to M . incognita , P k M i , in a wild peach species, we reconstructed a linkage group in a BC 1 population of 187 lines using resistance gene analogue markers surrounding the P k M i locus. A resistance gene analogue marker, ppa021062m, co‐segregated with the P k M i locus and was therefore considered a strong candidate for P k M i . Phylogenetic analysis of the deduced protein sequences of ppa021062m, together with the other seven genes for nematode resistance, allowed ppa021062m to be assigned to the Toll/Interleukin1 R eceptor‐ N ucleotide B inding S ite‐ L eucine R ich R epeat class, similar to Ma in myrobalan plum ( P . cerasifera ). Comparative analysis of the candidate gene sequence in four genotypes that had different levels of resistance to root‐knot nematode disease showed that most non‐synonymous SNP s in the genic region were distributed in the TIR and NBS motifs. This study enhances our understanding of the genetic and molecular control of resistance to root‐knot nematode disease in peach.