First Record of Comparative Plastid Genome Analysis and Phylogenetic Relationships among Corylopsis Siebold & Zucc. (Hamamelidaceae).

Corylopsis Siebold & Zucc. (Hamamelidaceae) is widely used as a horticultural plant and comprises approximately 25 species in East Asia. Molecular research is essential to distinguish Corylopsis species, which are morphologically similar. Molecular research has been conducted using a small number of genes but not in Corylopsis . Plastid genomes of Corylopsis species ( Corylopsis gotoana, Corylopsis pauciflora , and Corylopsis sinensis ) were sequenced using next-generation sequencing techniques. Repeats and nucleotide diversity that could be used as DNA markers were also investigated. A phylogenetic investigation was carried out using 79 protein-coding genes to infer the evolutionary relationships within the genus Corylopsis . By including new plastomes, the overall plastid genome structure of Corylopsis was similar. Simple sequence repeats of 73-106 SSRs were identified in the protein-coding genes of the plastid genomes, and 33-40 long repeat sequences were identified in the plastomes. The Pi value of the rpl33_rps18 region, an intergenic spacer, was the highest. Phylogenetic analysis demonstrated that Corylopsis is a monophyletic group and Loropetalum is closely related to Corylopsis . C. pauciflora, C. gotoana , and C. spicata formed a clade distributed in Japan, whereas C. sinensis , C. glandulifera , and C. velutina formed a clade that was distributed in China.