Sequence Analysis of the Plastomes of Two Tibetan Medicinal Plants of the Family .

BACKGROUND

With the rapid development of next-generation sequencing technology, more plants plastomes have been sequenced, further advancing species identification and phylogenetic studies. However, there are a few studies on the genetic and phylogenetic analysis of the plastomes of Hook. f. et Thoms. and Hook. f. et Thoms.

METHODS

In this study, we sequenced and analyzed the plastomes of Hook. f. et Thoms. and Hook. f. et Thoms., and conducted a phylogenetic analysis using 13 related species.

RESULTS

The results showed that the plastomes of both and had a typical tetrad structure, with sizes of 166,819 bp and 163,282 bp, respectively. We annotated 133 genes for and 120 genes for . A total of 72 and 43 simple repetitive sequences were detected in and , respectively. Codon preference analysis showed that the relative usage frequency of codons and the relative abundance of synonymous codons used were the same for both plastomes. Nucleotide polymorphism analysis identified seven variant loci with high nucleotide diversity (Pi) values, all located in the large single copy (LSC) region. Inverted repeat (IR) boundary analysis revealed differences in gene types and locations on both sides of the boundary, except for the small single copy/inverted repeat a (SSC/IRa) boundary. The phylogenetic analysis showed the species clustered into two major groups, one with five genera (, , , psis, and ) and the other with two genera (; and ).

CONCLUSIONS

Comparative analysis of the plastome genomic characteristics and phylogeny of and laid the foundation for identifying the above two species and the phylogenetic study and comprehensive exploitation of the .