Comparative chloroplast genome analysis of medicinally important (Melanthiaceae) in China: Insights into genomic characterization and phylogenetic relationships.

Members of are perennial herbs widely used in traditional Chinese medicine to induce vomiting, resolve blood stasis and relieve pain. However, the intrageneric classification and phylogenetic relationships within have long been controversial due to the complexity of morphological variations and lack of high-resolution molecular markers. In this study, we reevaluated the infrageneric relationships with the genus using complete chloroplast genome sequence data. Herein, the complete cp genomes of ten species of were newly sequenced and characterized. The complete cp genomes of ten species of had the typical quadripartite structure, ranging from 151,597 bp to 153,711 bp in size and comprising a total of 135 genes. The structure of cp genomes (i.e., gene order, content, and genome components) was highly similar across species. The number of simple sequence repeats (SSRs) ranged from 63 to 78, and of long repeats ranged from 31 to 35. Eight highly divergent regions (, , , GCA, UUUUUG, GCUUCC, UGUUAA and ) were identified and are potentially useful for the DNA barcoding of . Phylogenetic analysis among 29 taxa based on cp genomes, total genes, protein-coding genes and intergenic regions strongly supported the monophyly of . The circumscription and relationships of the infrageneric taxa of were well-presented with great resolution. These results will facilitate the identification, taxonomy, and utilization of plants as well as the evolutionary studies of Melanthiaceae.