A genetic linkage map of Physocarpus, a member of the Spiraeoideae (Rosaceae), based on RAPD, AFLP, RGA, SSR and gene specific markers

Abstract

Physocarpus opulifolius is a deciduous shrub native to North America belonging to the Spiraeoideae subfamily of the Rosaceae. The cultivars ÔLuteusÕ and ÔDiaboloÕ are grown in gardens for their ornamental foliage, golden and purple respectively. We developed a linkage map of P. opulifolius with a view to detecting markers for the leaf colour genes, which are under major gene control. A total of 162 molecular markers (128 RAPDs, 27 AFLPs, three RGA, three STS markers and one SSR) and the leaf colour genes Pur and Aur were scored in the Physocarpus progeny and used to create a linkage map covering 586.1 cM over nine linkage groups. There was an average of 18.2 markers per linkage group and a mean linkage group length of 65.1 cM. Both leaf colour genes were mapped. This is the first reported linkage map of a member of the Spireaeoideae and the mapping of a small number of transferable markers has demonstrated its utility to comparative mapping, which will complement existing comparative mapping efforts in other rosaceous subfamilies.

Physocarpus opulifolius (L.) Maxim ‘Donna May’: A New Compact, Purple-leafed Landscape Shrub

“…The resulting seedlings segregated for purple and green foliage and were generally intermediate in growth habit. Segregation of purple vs. green leaves in this population is consistent with the finding of Sutherland et al (2008) that 'Monlo' is heterozygous for Pur. Genotypes from this population with purple foliage and mildew resistance were retained as parents.…”

“…Leaf color segregation data from progeny of 'Donna May' are consistent with 'Donna May' being heterozygous for the Pur gene as would be expected from its pedigree. 'Donna May' and its compact purple-leafed siblings were allowed to intermate in isolation in 2007 (ninebark is self-incompatible; Sutherland et al, 2008). The segregation data for purple vs. green offspring from the bulked seed collected off of these plants fit the expected 3:1 ratio for offspring from parents heterozygous for Pur (Table 2).…”

“…Helping to spur on the increase in new cultivars is the fact that purple and gold foliage color in ninebark are simply inherited and easily recovered in progeny. Purple and gold foliage are controlled by different single genes (Pur and Aur located on linkage groups I and III, respectively) and by dominant alleles (Sutherland et al, 2008). Additional reasons for the increased popularity of ninebark is that it is a durable, easy-to-grow U.S. native shrub and can be used as an alternative to purple and yellow-leafed barberry in regions where barberry is deemed invasive (Lubell et al, 2011) or in situations in which the spines of barberry are a liability.…”

Genotyping-by-sequencing in an orphan plant species Physocarpus opulifolius helps identify the evolutionary origins of the genus Prunus

“…The ornamental genus Physocarpus (Nelliaea 2 n = 2 x = 18) in the Spiraeoideae was positioned as an immediate sister genus to Prunus in a comprehensive phylogeny of the Rosaceae [ 1 ]. A molecular map, based on a segregating F 2 progeny was reported for the species, which spanned the expected nine linkage groups and contained a total of 181 molecular markers across 586.1 cM, along with two genes controlling leaf colour [ 9 ]. Although the authors reported the positions of three sequence-characterised gene-specific markers and a single Malus SSR marker, the remaining 177 markers were either AFLP or RAPD markers and thus were not readily applicable to comparative genomic studies with other Rosaceous genera.…”

“…In this investigation, we have elaborated the previously published genetic linkage map of Physocarpus [ 9 ] using SNP markers identified through GBS. We used this map to study the extent of the genome diversification between the Physocarpus genus, with a base chromosome number of x = 9 and Prunus , x = 8, its phylogenetically close relation for which a full genome sequence is available.…”