The diploid origins of allopolyploid rose species studied using single nucleotide polymorphism haplotypes flanking a microsatellite repeat

Abstract

SummaryThe taxonomy of the genus Rosa is complex, not least because of hybridisations between species. We aimed to develop a method to connect the diploid Rosa taxa to the allopolyploid taxa to which they contributed, based on the sharing of haplotypes. For this we used an SNPSTR marker, which combines a short tandem repeat (STR; microsatellite) marker with single nucleotide polymorphisms (SNPs) in the flanking sequences. In total, 53 different sequences (haplotypes) were obtained for the SNPSTR marker, Rc06, from 20 diploid and 35 polyploid accessions from various species of Rosa. Most accessions of the diploid species had only one allele, while accessions of the polyploid species each contained two-to-five different alleles. Twelve SNPs were detected in the flanking sequences, which alone formed a total of 18 different haplotypes. A maximum likelihood dendrogram revealed five groups of haplotypes. Diploid species in the same Section of the genus Rosa contained SNP haplotypes from only one haplotype group. In contrast, polyploid species contained haplotypes from different haplotype groups. Identical SNP haplotypes were shared between polyploid species and diploid species from more than one Section of the genus Rosa. There were three different polymorphic repeat regions in the STR region. The STR repeat contained eight additional SNPs, but these contributed little to the resolution of the haplotype groups. Our results support hypotheses on diploid Rosa species that contributed to polyploid taxa. Finding different sets of haplotypes in different groups of species within the Sections Synstylae and Pimpinellifoliae supports the hypothesis that these may be paraphyletic.