The complete plastome sequence of Platanthera japonica (Orchidaceae): an endangered medicinal and ornamental plant

Platanthera japonica (Thunb. ex A. Marray) Lindl belongs to the genus Platanthera within family Orchidaceae, is an endangered herbal species in the East Asia area. In this study, the complete plastome sequence (cpDNA) of P. japonica was determined by next-generation Illumina sequencing. The cpDNA of this herbal plant is 155,409 bp in size, with a pair of inverted repeat (IR) regions of 26,933 bp that separate a large single-copy (LSC) region of 84,049 bp and a small single-copy (SSC) region of 17,494 bp. The GC content in plastome is 36.9%, and the IR region (43.2%) is higher than that of the LSC and SSC region (34.4% and 29.7%, respectively), which is similar with other Orchidaceae plastomes. The assembled plastome encoded 133 genes, which included 38 tRNA genes, 8 rRNA genes, and 87 protein-coding genes. A total of 24 species were used to construct the phylogenetic relationships among P. japonica and other related species within Orchidaceae. The results showed that P. japonica is closely related to Platanthera chlorantha.