Comparative Analysis of Chloroplast Genome Structure and Phylogenetic Relationships Among Six Taxa Within the Genus Catalpa (Bignoniaceae)

The complete plastome of Campsis radicans (L.) Bureau 1864 and its phylogenetic analysis

Campsis radicans (L.) Bureau 1864, a species of Bignoniaceae, has a widespread paleotropical distribution and is utilized for horticultural and traditional Chinese medicinal purposes. Despite the plant's significance, its genetic diversity must be better understood. In this study, we have successfully assembled and characterized the complete plastome of C. radicans, marking a significant advancement toward comprehending its genetic composition. The plastome is 153,630 bp long and harbors 130 genes, including 86 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Our phylogenomic analysis of the representative species of Bignoniaceae indicated that C. radicans formed a monophyletic sister clade of Campsis with C. grandiflora. These findings are crucial for conserving and utilizing this important plant species. They also highlight the potential for future research into the evolution and preservation of C. radicans, which could be advantageous in pharmaceutical applications.

Application of chloroplast genome in the identification of Phyllanthus urinaria and its common adulterants

BACKGROUND

Phyllanthus urinaria L. is extensively used as ethnopharmacological material in China. In the local marketplace, this medicine can be accidentally contaminated, deliberately substituted, or mixed with other related species. The contaminants in herbal products are a threat to consumer safety. Due to the scarcity of genetic information on Phyllanthus plants, more molecular markers are needed to avoid misidentification.

METHODS

In this study, the complete chloroplast genome of nine species of the genus Phyllanthus was de novo assembled and characterized.

RESULTS

This study revealed that all of these species exhibited a conserved quadripartite structure, which includes a large single copy (LSC) region and small single copy (SSC) region, and two copies of inverted repeat regions (IRa and IRb), which separate the LSC and SSC regions. And the genome structure, codon usage, and repeat sequences were highly conserved and showed similarities among the nine species. Three highly variable regions (trnS-GCU-trnG-UCC, trnT-UGU-trnL-UAA, and petA-psbJ) might be helpful as potential molecular markers for identifying P. urinaria and its contaminants. In addition, the molecular clock analysis results showed that the divergence time of the genus Phyllanthus might occur at ~ 48.72 Ma.

CONCLUSION

This study provides valuable information for further species identification, evolution, and phylogenetic research of Phyllanthus.