Complete chloroplast genome of Asarum chungbuensis (CS Yook & JG Kim) BU Oh 2005 (Aristolochiaceae), a Korean endemic species

Asarum chungbuensis, a species endemic to Korea, has a limited distribution across the Korean Peninsula and is used in traditional medicine. Despite its importance, the genome structure, genetic composition, and phylogenetic relationships based on its chloroplast genome have not been documented. In this study, the complete chloroplast genome of A. chungbuensis was newly assembled. The chloroplast genome is 190,179 base pairs (bp) long, and the overall GC content (%) of the plastid was 36.8%. The chloroplast genome size of A. chungbuensis is longer than that of the normal chloroplast genome (160 kb) because of an inverted small single-copy (SSC) duplication that incorporates the SSC into an inverted repeat (IR) region. By extension, this duplication event causes this chloroplast genome to lack an SSC, unlike other formal structures. The chloroplast genome, with a tripartite structure, consisted of a single-copy region of 93,351 bp with a 34.6% GC content and two IR regions, each with a length of 48,414 bp and a 38.8% GC content. Additionally, it was found to have 113 genes, including 79 PCG genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis revealed that A. chungbuensis was grouped with A. heterotropoides var. seoulense, which diverged from the clade comprising A. koreanum and A. patens. The newly sequenced A. chungbuensis chloroplast genome could provide valuable genomic information for determining unique genome structures, especially for the assessment of genetic diversity, phylogenetic relationships, species conservation, and biogeographic studies of the genus Asarum.