Comparative and phylogeny analysis of Asarum caudigerum and A. cardiophyllum complete chloroplast genomes

The complete chloroplast genome of medicinal plant Asarum caudigerum Hance and its close relative A. cardiophyllum Franchet were sequenced using Illumina Hiseq technology, and assembled, annotated, and characterized by bioinformatic methods in this study. Then phylogenetic analysis of the complete chloroplast genomes of A. caudigerum, A. cardiophyllum, and twelve published species was conducted. The results indicated that the chloroplast genomes ranged from 186 215-186 985 bp in length, with a large single copy (LSC, 89 445-90 169 bp) and two inverted repeats (IRa/IRb, 48 387-48 408 bp). The overall GC content was 37.4%-37.5%. A total of 144 chloroplast genes were annotated, including 98 protein coding genes, 38 tRNA genes and 8 rRNA genes. In addition, complex genomic rearrangements were detected in the chloroplast genome of Asarum. Meanwhile, visual evaluation of the discrete type of the sequence indicated that the variation level of non-coding region was higher than that of coding region. Phylogenetic analyses suggested that A. caudigerum and A. cardiophyllum were clustered into a single clade and A. cardiophyllum, A. sieboldii var. seoulense, A. misandrum and A. maculatum were clustered into another single branch. These two clade were sister species. This study provides a scientific basis for the identification, phylogenetic relationship, molecular breeding of Asarum species.