The complete chloroplast genome sequences of 11 Panax species: Providing insights for evolution and species identification
Pengguo Xia, Yang Huang, Junqiao Zhu
Abstract
Several species in the Panax L .(Araliaceae) are known worldwide for their remarkable medicinal value. However, morphological similarities among the species of Panax , the high number of transitional types, and uneven intercontinental distribution have led to confusion in the taxonomic status of its species. In this study, the cp genomes of 11 Panax species were subjected to high-throughput sequencing comparison and analysis. Like most angiosperms, the cp genomes of the 11 species showed a typical tetrad structure, each encoding eight rRNA genes, 36–37 tRNA genes, and 85–88 protein genes. The cp genome sizes of the 11 Panax species ranged from 156,064 to 156,993 bp, consisting of a large single-copy region (86,095–86,322 bp), a single-copy region (17,935–18,174 bp), and two inverted repeat regions (25,887–26,136 bp). SSRs in Panax were mainly single nucleotide repeats. For the 11 Panax species, the analysis of Ka/Ks values showed that the ycf2 gene exhibited significant positive selection. Further, phylogenetic analyses revealed that 11 Panax species clustered together. Moreover, the highly variable regions we labeled will provide the basis for subsequent molecular marker studies to identify species within Panax . Overall, this study provides a basis for promoting the phylogeny, genetic studies, and resource protection of Panax species. • The genus Panax L. is recognized worldwide for its valuable medicinal properties. • Comparative genomics of this genus reveals conserved chloroplast gene arrangement. • Phylogenetic analysis confirms close relationships between Panax species. • Nucleotide diversity analysis identifies polymorphic sites of chloroplast genomes.