Characterization and phylogenetic analysis of the complete plastome sequence of Thunia alba (Lindley) H. G. Reichenbach (Orchidaceae), a rare wild ornamental orchid

Thunia alba (Lindley) H. G. Reichenbach is a wild ornamental orchid, and it is a rare plant species with small populations. In this study, the complete chloroplast genome sequence of T. alba was assembled using short reads produced by high-throughput sequencing technologies. The whole chloroplast genome was 159,948 bp in length with a typical quadripartite structure, which consisted of a large single-copy (LSC), a small single-copy (SSC), and two inverted repeats (IRs). The sizes of LSC, SSC, and IR were 87,532, 18,852, and 26781 bp, with GC contents of 35.0%, 30.3%, and 43.2%, respectively. There were a total of 135 genes, which included 88 protein-coding genes, 8 rDNA genes, 38 tRNA genes, and a pseudogene. A phylogenetic tree was generated using the maximum-likelihood method, and the results revealed that T. alba was sister to Pleione bulbocodioides and Pleione formosana, with a support rate of 100%.