The Chloroplast Genome of Wild Saposhnikovia divaricata: Genomic Features, Comparative Analysis, and Phylogenetic Relationships

Abstract

Saposhnikovia divaricata, a well-known Chinese medicinal herb, is the sole species under the genus Saposhnikovia of the Apiaceae subfamily Apioideae Drude. However, information regarding its genetic diversity and evolution is still limited. In this study, the first complete chloroplast genome (cpDNA) of wild S. divaricata was generated using de novo sequencing technology. Similar to the characteristics of Ledebouriella seseloides, the 147,834 bp-long S. divaricata cpDNA contained a large single copy, a small single copy, and two inverted repeat regions. A total of 85 protein-coding, 8 ribosomal RNA, and 36 transfer RNA genes were identified. Compared with five other species, the non-coding regions in the S. divaricata cpDNA exhibited greater variation than the coding regions. Several repeat sequences were also discovered, namely, 33 forward, 14 reverse, 3 complement, and 49 microsatellite repeats. Furthermore, phylogenetic analysis using 47 cpDNA sequences of Apioideae members revealed that L. seseloides and S. divaricata clustered together with a 100% bootstrap value, thereby supporting the validity of renaming L. seseloides to S. divaricata at the genomic level. Notably, S. divaricata was most closely related to Libanotis buchtormensis, which contradicts previous reports. Therefore, these findings provide a valuable foundation for future studies on the genetic diversity and evolution of S. divaricata.