AUTHOR=Qian Shaojuan , Zhang Yonghong , Lee Shiou Yih 

TITLE=Comparative Analysis of Complete Chloroplast Genome Sequences in Edgeworthia (Thymelaeaceae) and New Insights Into Phylogenetic Relationships

JOURNAL=Frontiers in Genetics

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.643552

DOI=10.3389/fgene.2021.643552

ISSN=1664-8021

ABSTRACT=<p>The complete chloroplast genomes of three species of <italic>Edgeworthia</italic> namely, <italic>Edgeworthia albiflora</italic>, <italic>Edgeworthia chrysantha</italic>, and <italic>Edgeworthia gardneri</italic> (Thymelaeaceae), are reported and characterized. The chloroplast genomes displayed a typical quadripartite structure with conserved genome arrangement and specific divergence. The genomes ranged in length from 172,708 to 173,621 bp and displayed similar GC content of 36.5–36.7%. A total of 138–139 genes were predicted, including 92–93 protein-coding, 38 tRNAs and eight rRNAs genes. Variation in the number of short simple repeats and inverted region boundaries of the three cp genomes were observed. A mutational hotspot was detected along the nucleotide sequence from the <italic>ndh</italic>F to the <italic>trn</italic>L-UAG genes. The chloroplast genome-based and internal transcribed spacer (ITS)-based phylogenetic analyses using maximum-likelihood (ML) and Bayesian inference (BI) revealed that <italic>E. albiflora</italic> diverged before <italic>E. chrysantha</italic> and <italic>E. gardneri</italic> and placed the <italic>Edgeworthia</italic> clade at the base of the Eurasian Daphne group with strong bootstrap support. With an effective taxonomic treatment of the species of <italic>Edgeworthia</italic>, further molecular analyses of their intra- and interspecific genetic variation are inclined to support the treatment of <italic>E. albiflora</italic> and <italic>E. gardneri</italic> as two natural groups. The genetic information obtained from this study will provide valuable genomic resources for the identification of additional species and for deducing the phylogenetic evolution of <italic>Edgeworthia</italic>.</p>