Characterization and Comparison of Two Complete Plastomes of Rosaceae Species (Potentilla dickinsiivar.glabrataandSpiraeainsularis) Endemic to Ulleung Island, Korea

Potentilla dickinsiivar.glabrataandSpiraea insularisin the family Rosaceae are species endemic to Ulleung Island, Korea, the latter of which is listed as endangered. In this study, we characterized the complete plastomes of these two species and compared these with previously reported plastomes of other Ulleung Island endemic species of Rosaceae (Cotoneaster wilsonii,Prunus takesimensis,Rubus takesimensis, andSorbus ulleungensis). The highly conserved complete plastomes ofP. dickinsiivar.glabrataandS. insularisare 158,637 and 155,524 base pairs with GC contents of 37% and 36.9%, respectively. Comparative phylogenomic analysis identified three highly variable intergenic regions (trnT-UGU/trnL-UAA,rpl32/trnL-UAG, andndhF/rpl32) and one variable genic region (ycf1). Only 6 of the 75 protein-coding genes have been subject to strong positive selection. Phylogenetic analysis of 23 representative plastomes within the Rosaceae supported the monophyly ofPotentillaand the sister relationship betweenPotentillaandFragariaand indicated thatS. insularisis sister to a clade containingCotoneaster,Malus,Pyrus, andSorbus. The plastome resources generated in this study will contribute to elucidating the plastome evolution of insular endemic Rosaceae on Ulleung Island and also in assessing the genetic consequences of anagenetic speciation for various endemic lineages on the island.