Characterization and Comparative Analysis of Complete Chloroplast Genome of Vachellia tortilis subsp. tortilis (Fabaceae)

The Vachellia tortilis subsp. tortilis is a dryland tree included in the Fabaceae family. The genus Vachellia includes 164 species, 38 subspecies, and 25 varieties. The taxonomic placement of Vachellia has historically been unstable; the genus was only recently segregated from Acacia. In this study, we sequenced and characterized the chloroplast genome of V. tortilis subsp. tortilis and compared it with those of related species. The total chloroplast genome length of V. tortilis subsp. tortilis was 164,956 bp, and it contained 132 genes: 87 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. Simple repeat analysis showed that the chloroplast genome of V. tortilis subsp. tortilis contained 273 repeats. Codon usage bias analysis showed that the chloroplast genome of V. tortilis subsp. tortilis encoded 24,633 codons. The phylogenetic analysis revealed two distinct clades in the genus Vachellia: the first comprises V. tortilis subsp. tortilis and Vachellia tortilis subsp. raddiana, while the second includes Vachellia flava, Vachellia seyal, and Vachellia nilotica. This study improves knowledge of evolutionary relationships in the genus Vachellia and provides valuable genetic resources.