The complete plastome of : Comparative and phylogenetic analyses of the genus (Araliaceae).

(Araliaceae) is an endangered and medicinally important plant endemic to China. However, phylogenetic relationships within the genus have remained unclear. In this study, we sequenced the complete plastome of and included previously reported plastomes to better understand the relationships between species and plastome evolution within the genus . The plastome of is 156,069 base pairs (bp) in length, consisting of a pair of inverted repeats (IRs, each 25,887 bp) that divide the plastome into a large single copy region (LSC, 86,126 bp) and a small single copy region (SSC, 8169 bp). The plastome contains 114 unigenes (80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes). Comparative analyses indicated that the plastome gene content and order, as well as the expansion/contraction of the IR regions, are all highly conserved within . No significant positive selection in the plastid protein-coding genes was observed across the eight species, suggesting the plastomes may have undergone a strong purifying selection. Our phylogenomic analyses resulted in a phylogeny with high resolution and supports for . Nine protein-coding genes and 10 non-coding regions presented high sequence divergence, which could be useful for identifying different species.