Characterization of the complete chloroplast genome of <i>Aconitum umbrosum</i> (Ranunculaceae) and its phylogenetic implications

<i>Aconitum umbrosum</i> (Korsh.) Kom. is a member of <i>Aconitum</i> subg. <i>Lycoctonum</i> distributed in northeastern Asia, including the Russian Far East, northeastern China, and the northern part of the Korean Peninsula. Its series placement has been controversial: it was traditionally assigned to ser. <i>Lycoctonia</i> but was transferred to ser. <i>Longicassidata</i> in a recent molecular reclassification. To provide a plastid genomic resource and assess its plastid affinity, we sequenced and characterized the complete chloroplast genome of <i>A. umbrosum</i>. The plastome was 157,227 bp long and had a typical quadripartite structure consisting of an 88,083 bp large single-copy region, a 16,948 bp small single-copy region, and two 26,098 bp inverted repeats; the overall GC content was 37.98%. The genome contained 110 genes, comprising 78 protein-coding genes, 28 tRNA genes, and four rRNA genes, of which 19 genes (8 protein-coding, 7 tRNA, and 4 rRNA genes) were duplicated in the inverted repeats. A phylogenetic analysis of 74 shared chloroplast protein-coding genes from <i>A. umbrosum</i> and 25 related taxa placed <i>A. umbrosum</i> as a sister to <i>A. sinomontanum</i> and close to <i>A. barbatum</i> var. <i>hispidum</i> and <i>A. barbatum</i> var. <i>puberulum</i>. This phylogenetic topology shows partial agreement with the broadened concept of ser. <i>Longicassidata</i> but also suggests that the plastid-level boundary between ser. <i>Longicassidata</i> and ser. <i>Lycoctonia</i> remains unclear. The plastome reported here provides a useful resource for future comparative studies of <i>Aconitum</i>, especially within the subg. <i>Lycoctonum</i>.