Chloroplast genome features of an important medicinal and edible plant:Houttuynia cordata(Saururaceae)

Houttuynia cordata(Saururaceae), an ancient and relic species, has been used as an important medicinal and edible plant in most parts of Asia. However, because of the lack of genome information and reliable molecular markers, studies on its population structure, or phylogenetic relationships with other related species are still rare. Here, wede novoassembled the complete chloroplast (cp) genome ofH.cordatausing the integration of the long PacBio and short Illumina reads. The cp genome ofH.cordatashowed a typical quadripartite cycle of 160,226 bp. This included a pair of inverted repeats (IRa and IRb) of 26,853 bp, separated by a large single-copy (LSC) region of 88,180 bp and a small single-copy (SSC) region of 18,340 bp. A total of 112 unique genes, including 79 protein-coding genes, 29 tRNA genes, and four rRNA genes, were identified in this cp genome. Eighty-one genes were located on the LSC region, 13 genes were located on the SSC region, and 17 two-copy genes were located on the IR region. Additionally, 48 repeat sequences and 86 SSR loci, which can be used as genomic markers for population structure analysis, were also detected. Phylogenetic analysis using 21 cp genomes of the Piperales family demonstrated thatH.cordatahad a close relationship with the species within theAristolochiagenus. Moreover, the results of mVISTA analysis and comparisons of IR regions demonstrated that the cp genome ofH.cordatawas conserved with that of theAristolochiaspecies. Our results provide valuable information for analyzing the genetic diversity and population structure ofH.cordata, which can contribute to further its genetic improvement and breeding.