The plastome of Phaius hainanensis (Orchidaceae): an endangered species endemic to Hainan province, China

Phaius hainanensis C. Z. Tang et S. J. Cheng is a species with extremely small populations and is endemic to China. Genetic data of this orchid species is minimal. With the aim to identify appropriate chloroplast markers for the use in conservation biology studies, the plastome of P. hainanenisis was assembled. The plastome of P. hainanensis is 158,314 bp in length and contains a large single copy region of 86,700 bp in length, a small single copy region of 18,452 bp, and a pair of inverted repeats of 26,581 bp. The annotation predicted 114 unique genes, including 80 protein-coding, 30 tRNAs, and four rRNAs. Seventeen genes contained a single intron and two genes (clpP and ycf3) have two introns. The GC content of P. hainanensis is 36.9%. Phylogenetic analysis indicated P. hainanensis is closely related to P. tancarvilleae, and it also supported that Phaius and Calanthe are sister groups. The plastome data reported in this study will contribute to further studies of phylogeny and conservation of Phaius species.