Chloroplast genome structure and phylogeny of Spiranthes sinensis, an endangered medicinal orchid plant

Spiranthes sinensis is an important medicinal plant of Spiranthes family and is currently in an endangered state. To better guide the systematic classification of S. sinensis, the complete genome of its chloroplast was sequenced and characterized. The complete chloroplast genome is 152,786 bp in length and contains a large single copy (LSC) region of 83,446 bp, a small single copy (SSC) region of 17,938 bp, and two inverted repeat (IR(A) and IR(B)) regions of 25,701 bp. The genome encodes 132 genes (112 unique genes), including 86 protein-coding genes (78 unique genes), 8 rRNA genes (4 unique genes), and 38 tRNA genes (30 unique genes). The total GC content of plasmid genome is 36.18%. Phylogenetic results indicated that S. sinensis is more closely related to Ludisia discolor, Goodyera schlechtendaliana, Goodyera fumata, and Goodyera procera. The study enriches the plasmid genomic information of S. sinensis and is of great significance for the genetic protection of this species.