The complete plastid genome of <i>Polygonatum gracile</i> P. Y. Li (Asparagaceae): characterization and phylogeny

<i>Polygonatum gracile</i> P. Y. Li is a perennial rhizomatous medicinal herb endemic to China with recognized medicinal value. Here, the first complete plastid genome of <i>P. gracile</i> is reported and characterized, and the phylogenetic relationships of <i>P. gracile</i> with other <i>Polygonatum</i> species are clarified by phylogenetic inferences based on complete plastid genome sequences. The complete plastid genome of <i>P. gracile</i> is 155,734 bp in length and exhibits the typical quadripartite circular structure consisting of a large single-copy (LSC, 84,385 bp) region, a small single-copy (SSC, 18,519 bp) region, and a pair of inverted repeat regions (IRa/b, 26,415 bp). A total of 112 unique genes, including 78 protein-coding genes, 30 tRNA genes, and four rRNA genes were identified. Seven protein-coding genes, eight tRNA genes, and four rRNA genes were duplicated in the IR regions. Phylogenetic reconstructions indicated that <i>P. gracile</i> belongs to sect. <i>Verticillata</i> and is most closely related to <i>P. zanlanscianense</i> Pamp. This study provides a basis for further phylogenetic reconstructions, conservation and utilization of <i>Polygonatum</i> species.