Angraecum, commonly known as Darwin’s orchid, is the largest genus of Angraecinae (Orchidaceae). This genus exhibits a high morphological diversity, making it as a good candidate for macroevolutionary studies. In this study, four complete plastomes of
Angraecum were firstly reported and the
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Angraecum, commonly known as Darwin’s orchid, is the largest genus of Angraecinae (Orchidaceae). This genus exhibits a high morphological diversity, making it as a good candidate for macroevolutionary studies. In this study, four complete plastomes of
Angraecum were firstly reported and the potential variability hotspots were explored. The plastomes possessed the typical quadripartite structure and ranged from 150,743 to 151,818 base pair (bp), with a guanine–cytosine (GC) content of 36.6–36.9%. The plastomes all contained 120 genes, consisting of 74 protein-coding genes (CDS), 38 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes; all
ndh genes were pseudogenized or lost. A total of 30 to 46 long repeats and 55 to 63 SSRs were identified. Relative synonymous codon usage (RSCU) analysis indicated a high degree of conservation in codon usage bias. The Ka/Ks ratios of most genes were lower than 1, indicating that they have undergone purifying selection. Based on the ranking of Pi (nucleotide diversity) values, five regions (
trnSGCU-
trnGGCC,
ycf1-
trnNGGU,
trnNGUU-
rpl32,
psaC-
ndhE and
trnSGCU-
trnGGCC) and five protein-coding genes (
rpl32,
rps16,
psbK,
rps8, and
ycf1) were identified. The consistent and robust phylogenetic relationships of
Angraecum were established based on a total of 40 plastomes from the Epidendroideae subfamily. The genus
Angraecum was strongly supported as a monophyletic group and sister to Aeridinae. Our study provides an ideal system for investigating molecular identification, plastome evolution and DNA barcoding for
Angraecum.
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