Hyuk-Jin Kim

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

BackgroundHybridization is an important evolutionary process that results in increased plant diversity. Flowering Prunus includes popular cherry species that are appreciated worldwide for their flowers. The ornamental characteristics were acquired both naturally and through artificially hybridizing species with heterozygous genomes. Therefore, the genome of hybrid flowering Prunus presents important challenges both in plant genomics and evolutionary biology.ResultsWe use long reads to sequence and analyze the highly heterozygous genome of wild Prunus yedoensis. The genome assembly covers >u200993% of the gene space; annotation identified 41,294 protein-coding genes. Comparative analysis of the genome with 16 accessions of six related taxa shows that 41% of the genes were assigned into the maternal or paternal state. This indicates that wild P. yedoensis is an F1 hybrid originating from a cross between maternal P. pendula f. ascendens and paternal P. jamasakura, and it can be clearly distinguished from its confusing taxon, Yoshino cherry. A focused analysis of the S-locus haplotypes of closely related taxa distributed in a sympatric natural habitat suggests that reduced restriction of inter-specific hybridization due to strong gametophytic self-incompatibility is likely to promote complex hybridization of wild Prunus species and the development of a hybrid swarm.ConclusionsWe report the draft genome assembly of a natural hybrid Prunus species using long-read sequencing and sequence phasing. Based on a comprehensive comparative genome analysis with related taxa, it appears that cross-species hybridization in sympatric habitats is an ongoing process that facilitates the diversification of flowering Prunus.

The complete chloroplast genome sequence of Hydrangea luteovenosa (Hydrangeaceae)

Abstract Hydrangea luteovenosa is a member of the family Hydrangeaceae. The complete chloroplast genome sequence of H. luteovenosa was characterized from MiSeq (Illumina Co.) pair-end sequencing data. The chloroplast genome of H. luteovenosa was 157,494u2009bp in length with a pair of inverted repeats (IRs) (25,126u2009bp) which were separated by a large single-copy (LSC) (86,596u2009bp) and a small single-copy regions (SSC) (18,646u2009bp). It contained 129 genes including 85 protein-coding genes, 36 tRNA genes, and 8 ribosomal RNA genes. The maximum-likelihood phylogenetic analysis with the previously reported chloroplast genomes showed that H. luteovenosa is most closely related to the tribe Hydrangeeae.