Complete Chloroplast Genomes and Comparative Analyses of Three Ornamental Impatiens Species

Abstract

Impatiens L., the largest genus in the family Balsaminaceae with approximately 1,000 species, is a controversial genus. Due to the conflict of morphological features and insufficient genomic resources, the studies of systematic evolution and understanding of taxonomic identification are considered to be very limited. Hence, we have sequenced the complete chloroplast genomes of three ornamental species (Impatiens balsamina, I. hawkeri, and I. walleriana), and compared them with previously published wild species data. We performed a detailed comparison of a highly similar basic structure, size, GC content, gene number, order, and functional array among them. Similarly, most divergent genes were detected from previous work in the literature. The mutational regions containing highly variable nucleotide hotspots were identified and may be used as potential markers for species identification and taxonomy. Furthermore, using whole chloroplast genome data to analysis the phylogenetic relationship of the Balsaminaceae species, we found that they were all part of a single clade. The three phenotypically different ornamental species were clustered together, suggesting that they were very likely to be closely related. We achieved and characterized the plastid genome structure, identified the divergence hotspots, and determined the phylogenetic and taxonomic positions of the three cultivated species in the Impatiens genus. The results may show that the chloroplast genome can be used to solve phylogenetic problems in or between the Impatiens genus and also provide genomic resources for the study of the Balsaminaceae family’s systematics and evolution.

Comparative analysis of chloroplast genome and new insights into phylogenetic relationships of Ajuga and common adulterants

“…Analysis of oligonucleotide repeat in seven cp genomes indicated that the number and length of repeat sequences differed among genomes and were distributed randomly, with repeat sequences ranging from 30 to 82 bp and most being within 30 -46 bp (Figure 4B). Meanwhile, 274 long repeats were identified, including 149 P repeats, 124 F repeats, and 1 R repeat, with P and F being more than R and C, a pattern consistent with most plastid genomes of angiosperms (Vu et al, 2020;Luo et al, 2022). R repeats were only present in A. campylantha, while C repeats were absent in all seven Ajuga species (Figure 4A).…”

Flower development and a functional analysis of related genes in Impatiens uliginosa

“…There are more than 1,000 species of Impatiens in the world ( Luo et al., 2022 ). Studies on their evolution and taxonomy show that the number of sepals is one of the signs of evolution.…”

Studies of the pollen characteristics and the taxonomic significance of Impatiens from the Yunnan–Guizhou Plateau

“…Impatiens is rich in germplasm resources, and there are approximately 120 species in the Yunnan-Guizhou Plateau (Luo et al, 2022). In this study of some areas of Yunnan and Guizhou, 48 species of Impatiens were collected, which is, of course, only a fraction of the local species.…”

“…There are two genera of the Balsaminaceae, and one is Impatiens. This genus is rich in germplasm resources, with more than 1 000 species in the world and more than 260 species in China (Luo et al, 2022). However, the classification of Impatiens is very challenging Hai-hao He 1 , Ming-lan Ma 1 , Xin-yi Chen 1 , Xin-yi Li 1 , Fan Li 1 , Qiu-yan Zhao 1 , Xiao-shuai He 1 , Yi Tan 1 , Su-ping Qu 2 , Hai-quan Huang 1, *, Mei-juan Huang 1, * because it is difficult to make and preserve specimens (Yu et al, 2016).…”

“…The primary classification methods of Impatiens are traditional taxonomy and molecular biology or a combination of both. In molecular biological classification, ITS sequences (Eddie et al, 2003;Yuan et al, 2004) and the chloroplast genomes (Luo et al, 2022) are commonly used for classification. Compared with molecular biology, traditional taxonomy primarily classifies plants based on morphology and palynology.…”