Complete chloroplast genome sequence of Adenophora racemosa (Campanulaceae): Comparative analysis with congeneric species

Adenophora racemosa, belonging to the Campanulaceae, is an important species because it is endemic to Korea. The goal of this study was to assemble and annotate the chloroplast genome of A. racemosa and compare it with published chloroplast genomes of congeneric species. The chloroplast genome was reconstructed using de novo assembly of paired-end reads generated by the Illumina MiSeq platform. The chloroplast genome size of A. racemosa was 169,344 bp. In total, 112 unique genes (78 protein-coding genes, 30 tRNAs, and 4 rRNAs) were identified. A Maximum likelihood (ML) tree based on 76 protein-coding genes divided the five Adenophora species into two clades, showing that A. racemosa is more closely related to Adenophora stricta than to Adenophora divaricata. The gene order and contents of the LSC region of A. racemosa were identical to those of A. divaricata and A. stricta, but the structure of the SSC and IRs was unique due to IR contraction. Nucleotide diversity (Pi) >0.05 was found in eleven regions among the three Adenophora species not included in sect. Remotiflorae and in six regions between two species (A. racemosa and A. stricta).