Mapping the H2 resistance effective against Globodera pallida pathotype Pa1 in tetraploid potato

• Published in: Theoretical and applied genetics 2019-04, Vol.132 (4), p.1283-1294
• Main Authors: Strachan, Shona M., Armstrong, Miles R., Kaur, Amanpreet, Wright, Kathryn M., Lim, Tze Yin, Baker, Katie, Jones, John, Bryan, Glenn, Blok, Vivian, Hein, Ingo
• Format: Article
• Language: English
• Subjects: Agriculture; Animals; Biochemistry; Biomedical and Life Sciences; Biotechnology; Chromosome 5; Chromosome Mapping; Chromosome Segregation - genetics; Chromosomes; Chromosomes, Plant - genetics; Crosses, Genetic; Disease resistance; Disease Resistance - genetics; Gene mapping; Genes; Genes, Dominant; Genes, Plant; Genetic aspects; Genetic Loci; Genetic research; Genomes; Genomics; Globodera pallida; H2 gene; Insect resistance (Plants); Life Sciences; NLR Proteins - metabolism; Original; Original Article; Phenotypes; Physiological aspects; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Diseases - genetics; Plant Diseases - parasitology; Plant Genetics and Genomics; Polymorphism, Single Nucleotide - genetics; Population genetics; Potatoes; Roundworms; Solanum tuberosum - genetics; Solanum tuberosum - immunology; Solanum tuberosum - parasitology; Tetraploidy; Tylenchoidea - pathogenicity; Vacuum
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-019-03278-4

Key message The nematode resistance gene H2 was mapped to the distal end of chromosome 5 in tetraploid potato. The H2 resistance gene, introduced into cultivated potatoes from the wild diploid species Solanum multidissectum , confers a high level of resistance to the Pa1 pathotype of the potato cyst nematode Globodera pallida . A cross between tetraploid H2 -containing breeding clone P55/7 and susceptible potato variety Picasso yielded an F1 population that segregated approximately 1:1 for the resistance phenotype, which is consistent with a single dominant gene in a simplex configuration. Using genome reduction methodologies RenSeq and GenSeq, the segregating F1 population enabled the genetic characterisation of the resistance through a bulked segregant analysis. A diagnostic RenSeq analysis of the parents confirmed that the resistance in P55/7 cannot be explained by previously characterised resistance genes. Only the variety Picasso contained functionally characterised disease resistance genes Rpi - R1 , Rpi - R3a , Rpi - R3b variant, Gpa2 and Rx , which was independently confirmed through effector vacuum infiltration assays. RenSeq and GenSeq independently identified sequence polymorphisms linked to the H2 resistance on the top end of potato chromosome 5. Allele-specific KASP markers further defined the locus containing the H2 gene to a 4.7 Mb interval on the distal short arm of potato chromosome 5 and to positions that correspond to 1.4 MB and 6.1 MB in the potato reference genome.