The first complete chloroplast genome sequence of Paris polyphylla var. emeiensis, a rare and endangered species

Comparative analysis of complete chloroplast genome sequences of five endangered species and new insights into phylogenetic relationships of Paris

Paris L. genus has been a precious traditional herb for more than 2000 years in China. However, due to overexploitation and habitat destruction, Paris is threatened by extinction. Similar morphological features cause the classification of Paris species in dispute. The chloroplast (cp) genome approach has been used to investigate the evolution of Paris. However, some studies confirm that the cp genome may result in misleading relationships because of the length variation, gaps/indels deletion, and incorrect models of sequence evolution in concatenated datasets. Therefore, there is a high demand for a reconstructed phylogenetic relationship and developed genetic markers to conserve these species. Recent studies have demonstrated that the protein-coding genes could provide a better phylogenetic relationship in the phylogenetic investigation. In this study, the complete cp genomes of five species were characterized, and the length of five cp genomes ranges from 162,927 bp to 165,267 bp, covering 89 protein-coding genes, 38 tRNA, and eight rRNA. The analysis of the repeat sequences, codon usage, RNA-editing sites, and comparison of cp genomes shared a high degree of conservation. Based on the protein-coding genes, the phylogenetic tree confirmed Paris's position in the order Melanthiaceae, providing maximum support for a sister relationship of the subgenera Paris sensu strict (Paris s.s.) with the Daiswa and Trillium. In addition, the molecular clock showed that subgenus Paris was inferred to have occurred at about 52.81 Mya, whereas subgenus Daiswa has originated at 24.56 Mya, which was consistent with the phylogenetic investigation. This study provided a valuable insight into the evolutionary dynamics of cp genome structure in the family Melanthiaceae, and it also contributes to the bioprospecting and conservation of Paris species.

The complete chloroplast genome sequence of Paris polyphylla var. alba H.Li & R.J.Mitchell and its phylogenetic analysis

Paris polyphylla var. alba is a medicinal plant commonly used in the southwest of China. This study characterized the complete chloroplast (cp) genome sequence of P. polyphylla var. alba to investigate its phylogenetic relationship in Melanthiaceae. The cp genome of P. polyphylla var. alba is 165,079 base pairs (bp) in length with 36.96% G + C content. The cp genome is divided into (a) large single copy (LSC) (84,393 bp), (b) small single copy (SSC) (16,066 bp), and (c) two inverted regions (32,310 bp). The cp genome contains 135 genes, including 89 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Phylogenetic analysis indicated that P. polyphylla var. alba is closest to P. polyphylla var. emeiensis, and Paris had a close relationship with Trillium in Melanthiaceae.

Chloroplast phylogenomic analysis provides insights into the evolution of Paris liiana sp. nov

Paris liiana sp. nov is a species of flowering herb of the genus Paris and widely distributed in the southwest of China. In this study, we sequenced the complete chloroplast (cp) genome of P. liiana sp. nov to investigate its phylogenetic relationship in genus Paris. The cp genome of P. liiana sp. nov was 163,860 bp in length, containing a large single-copy (LSC) region of 84,415 bp, a small single-copy (SSC) region of 12,947 bp, and a pair of inverted repeats (IRs) region of 33,249 bp. The overall GC content was 37.0%. The genome comprises of 135 genes, including 91 protein-coding genes, 37 tRNA genes, and 4 rRNA genes. Phylogenetic relationship analysis based on complete cp genome sequences exhibited that P. liiana sp. nov was most related to P. polyphylla var. yunnanensis.