Chloroplast Genome of Salvia Sect. Drymosphace: Comparative and Phylogenetic Analysis

Abstract

Sect. Drymosphace is one of eight sections of Salvia subg. Glutinaria and includes 13 species and one dubious species that hold great economic value. Although the section is well supported, interspecific relationships remain unresolved. Moreover, most of this section’s plastome information remains unknown. In this study, we sequenced and assembled eight sect. Drymosphace plastomes and conducted comparative analyses within this section. The length of plastid genome sequences ranged from 151,330 bp to 151,614 bp, with 80 protein-coding, 30 tRNA, and four rRNA genes being annotated. The plastomes were found to be as conservative as other Lamiaceae species, showing high consistency and similarity in terms of gene content, order, and structure. Within the sect. Drymosphace, single-copy regions were more variable than IR regions, and the intergenic regions were more variable than the coding regions; nine hypervariable regions were detected, and some of them may be useful for the phylogenetic analysis of Salvia. The topologies inferred from all of the data sets indicated that sect. Drymosphace was monophyletic and that S. honania was sister to S. meiliensis. Compared to previous studies involving more sect. Drymosphace species, phylogenomic analyses can improve the phylogenetic resolution considerably.