Complete Chloroplast Genomes of 9 Impatiens Species: Genome Structure, Comparative Analysis, and Phylogenetic Relationships

<i>Impatiens</i> is a genus of functional herbaceous plants in the Balsaminaceae, which are not only of great ornamental value and one of the world's top three flower bedding plants but also have a wide range of medicinal and edible uses. Currently, the taxonomy and phylogenetic relationships of <i>Impatiens</i> species are still controversial. In order to better understand their chloroplast properties and phylogenetic evolution, nine <i>Impatiens</i> plants (<i>Impatiens repens</i>, <i>Impatiens rectirostrata</i>, <i>Impatiens baishaensis</i>, <i>Impatiens rostellata</i>, <i>Impatiens faberi</i>, <i>Impatiens oxyanthera</i>, <i>Impatiens tienchuanensis</i>, <i>Impatiens blepharosepala</i>, <i>Impatiens distracta</i>) were sequenced, and their complete chloroplast genomes were analysed. Nine species of <i>Impatiens</i> chloroplast genomes ranged in length from 150,810 bp (<i>I. rectirostrata</i>) to 152,345 bp (<i>I. blepharosepala</i>). The chloroplast genomes were all typical circular DNA molecules, and the GC content in each region was consistent with the published chloroplast genomes of <i>Impatiens</i> plants. The results showed that the seven mutational hotspots (<i>trnL-UAG</i>, <i>ndhG</i>, <i>ycf1</i>, <i>ccsA</i>, <i>rrn23</i>, <i>trnA-UGC</i>, and <i>ycf2</i>) could be used as supporting data for further analyses of the phylogenetic tree and species identification. In addition, the results of the phylogenetic tree support that Balsaminaceae is a monophyletic taxon, and that <i>Hydrocera triflora</i> is at the base of the branch, is the original species of Balsaminaceae, and is in a sister group relationship with <i>Impatiens</i> species. The results of this paper enrich the data of <i>Impatiens</i> chloroplast genomes, and the availability of these chloroplast genomes will provide rich genetic information for species identification, thus enhancing the taxonomic accuracy and phylogenetic resolution of <i>Impatiens</i>, and further promoting the investigation and rational use of <i>Impatiens</i> plant resources.