Identification of a polymorphism within the Rosa multiflora muRdr1A gene linked to resistance to multiple races of Diplocarpon rosae W. in tetraploid garden roses (Rosa × hybrida)

• Published in: Theoretical and applied genetics 2020, Vol.133 (1), p.103-117
• Main Authors: Rouet, Cindy, Lee, Elizabeth A., Banks, Travis, O’Neill, Joseph, LeBlanc, Rachael, Somers, Daryl J.
• Format: Article
• Language: English
• Subjects: Agriculture; Alleles; Ascomycota - physiology; Base Sequence; Biochemistry; Biomedical and Life Sciences; Biotechnology; Black spot; Botanical research; Chromosome 1; Chromosome Mapping; Chromosome Segregation - genetics; Crosses, Genetic; Diplocarpon rosae; Disease Resistance - genetics; Diseases and pests; Foliar diseases; Gene mapping; Gene polymorphism; Genes, Plant; Genetic aspects; Genetic Association Studies; Genetic Markers; Genotyping; Host Specificity - genetics; Life Sciences; Marker-assisted selection; Models, Genetic; Original Article; Phenotype; Physiological aspects; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant immunology; Polymorphism; Polymorphism, Single Nucleotide - genetics; Quantitative trait loci; Quantitative Trait Loci - genetics; Rosa - genetics; Rosa - microbiology; Roses; Single nucleotide polymorphisms; Single-nucleotide polymorphism; Tetraploidy
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-019-03443-9

Key message A QTL for resistance to several races of black spot co-located with the known Rrd1 locus in Rosa. A polymorphism in muRdr1A linked to black spot resistance was identified and molecular markers were designed. Black spot, caused by Diplocarpon rosae , is one of the most serious foliar diseases of landscape roses that reduces the marketability and weakens the plants against winter survival. Genetic resistance to black spot (BS) exists and race-specific resistance is a good target to implement marker-assisted selection. High-density single nucleotide polymorphism-based genetic maps were created for the female parent of a tetraploid cross between ‘CA60’ and ‘Singing in the Rain’ using genotyping-by-sequencing following a two-way pseudo-testcross strategy. The female linkage map was generated based on 227 individuals and included 31 linkage groups, 1055 markers, with a length of 1980 cM. Race-specific resistance to four D. rosae races (5, 7, 10, 14) was evaluated using a detached leaf assay. BS resistance was also evaluated under natural infection in the field. Resistance to races 5, 10 and 14 of D. rosae and field resistance co-located on chromosome 1. A unique sequence of 32 bp in exon 4 of the muRdr1A gene was identified in ‘CA60’ that co-segregates with D. rosae resistance. Two diagnostic markers, a presence/absence marker and an INDEL marker, specific to this sequence were designed and validated in the mapping population and a backcross population derived from ‘CA60.’ Resistance to D. rosae race 7 mapped to a different location on chromosome 1.