Molecular and morphological data reveal hybrid origin of wild Prunus yedoensis (Rosaceae) from Jeju Island, Korea: implications for the origin of the flowering cherry.

The subgenus Cerasus of the genus Prunus includes several popular ornamental flowering cherries. Of the hundreds of cultivars, P. ×yedoensis ('Somei-yoshino') is the most popular and familiar cultivar in Korea and Japan and is considered to be of hybrid origin. However, the hybrid origin of P. ×yedoensis and its relationship to wild P. yedoensis, naturally occurring on Jeju Island, Korea, are highly controversial. We extensively sampled wild P. yedoensis, cultivated P. ×yedoensis, and numerous individuals from other species belonging to subgenus Cerasus on Jeju Island. Samples from 71 accessions, representing 13 species and one cultivar (P. ×yedoensis), were sequenced for nrDNA ITS/ETS (952 characters) and seven noncoding cpDNA regions (5421 characters) and subjected to maximum parsimony and maximum likelihood analysis. Additive polymorphisms in the ITS/ETS regions were confirmed by cloning amplicons from representative species. The nuclear (ITS/ETS and G3pdh) and cpDNA data, along with several morphological characteristics, provide the first convincing evidence for the hybrid origin of wild P. yedoensis. The maternal parent was determined to be P. spachiana f. ascendens, while the paternal parent was unresolved from the taxonomically complex P. serrulata/P. sargentii clade. The presence of two kinds of ribotypes was confirmed by cloning, and the possible origin of cultivated P. ×yedoensis from wild populations on Jeju Island was also suggested. Bidirectional and multiple hybridization events were responsible for the origin of wild P. yedoensis. Extensive gene flow was documented in this study, suggesting an important role of reticulate evolution in subgenus Cerasus.

Cho MS ，Kim CS ，Kim SH ，Kim TO ，Heo KI ，Jun J ，Kim SC ... -  《-》

Multiple Lines of Evidence for Independent Origin of Wild and Cultivated Flowering Cherry (Prunus yedoensis).

As with many other ornamental and cultivated plants that have been under human selection and cultivation for a long time, it has been a major challenge to trace back the complex evolutionary history of flowering cherry, Prunus yedoensis. This challenge has been further amplified by great morphological similarities, little molecular divergence, frequent natural and artificial hybridization, and poor documentation of breeding history among cultivated and wild flowering cherries. The origin and taxonomic distinction between wild P. yedoensis from Jeju Island, Korea, and one of the most popular cultivated flowering cherries, P. × yedoensis "Somei-yoshino" has been a controversy for the past few decades. We sampled many areas extensively, and using four different molecular markers we provided evidence for their independent origin. Wild P. yedoensis in Korea originated from multiple bidirectional hybridization events between two sympatric species, P. spachiana f. ascendens as the maternal species and P. serrulata var. spontanea/P. serrulata var. quelpaertensis as the most probable paternal species. On the contrary, our results supported a single artificial hybrid origin of P. × yedoensis "Somei-yoshino" from cultivated P. spachiana f. ascendens as the maternal species and P. speciosa, a species endemic to Izu Islands, as the paternal species. Based on extensive sampling, we provided strong evidence that wild and cultivated P. yedoensis are distinct taxonomic entities that have originated from different evolutionary processes. A potential for the development of new cultivars from wild P. yedoensis and conservation of diverse germplasms in situ insular setting and ex situ should be explored in the future.

Cho MS ，Kim SC 《Frontiers in Plant Science》

Complete chloroplast genome of Prunus yedoensis Matsum.(Rosaceae), wild and endemic flowering cherry on Jeju Island, Korea.

Cho MS ，Hyun Cho C ，Yeon Kim S ，Su Yoon H ，Kim SC ... -  《-》

Fine mapping of a locus presumably involved in hybrid inviability (HIs-1) between flowering cherry cultivar Cerasus × yedoensis 'Somei-yoshino' and its wild relative C. spachiana.

Flowering cherry is an extremely renowned ornamental tree, consisting of a variety of species and cultivars. Because cherry species have no strict barriers for interspecific hybridization before fertilization, identification of the gene underlying post-zygotic hybrid inviability will help breeders identify specimens for breeding and help us understand speciation mechanisms. In this study, we mapped the genetic linkages and physical genome sequences for a presumed hybrid inviability locus (HIs-1) that we observed in the seedlings crossed between Cerasus × yedoensis 'Somei-yoshino' and its wild relative C. spachiana. By the surveying linkage maps of 'Somei-yoshino' and C. spachiana, we identified correlation with seedling inviability only in linkage group 4 (LG4) of the 'Somei-yoshino' map. When we produced a finer-scaled map of HIs-1 in LG4, we found that HIs-1 is located between two microsatellite (SSR) markers with a 3.8 cM span. Using eight SSR markers based on peach genome sequences, we further refined the candidate region for HIs-1. This region was located between Pp04C001 and Pp04C007 markers, spanning 240 Kb of the peach genome, in which 45 transcribed genes had been estimated. From these candidate genes, it will be feasible to identify molecular mechanisms involved in cherry hybrid inviability.

Tsuruta M ，Mukai Y 《-》

Draft genome sequence of wild Prunus yedoensis reveals massive inter-specific hybridization between sympatric flowering cherries.

Baek S ，Choi K ，Kim GB ，Yu HJ ，Cho A ，Jang H ，Kim C ，Kim HJ ，Chang KS ，Kim JH ，Mun JH ... -  《GENOME BIOLOGY》