Complete Chloroplast Genomes and Comparative Analyses of Three Ornamental Impatiens Species

Complete chloroplast genomes of 13 species of the Impatiens genus for genomic features and phylogenetic relationships studies

Impatiens spp. are well-known ornamental and medicinal plants that are widely distributed in the highlands and mountains of southwestern China. This area is one of the hotspots for the distribution of Impatiens species, with typical karst landforms and abundant wild resources. Many of these species are endemic to a narrow distribution area, but their classification and relationships are relatively unclear because of insufficient field investigations, diverse morphological characteristics and lack of molecular information. In this study, chloroplast genome analysis of 13 species (including 2 synonyms) in karst habitats was conducted to study their characteristics and phylogenetic relationships. The results revealed that these chloroplast genomes all had double-stranded tetrad structures ranging in length from 151,284 bp to 152,421 bp, including a total of 113 genes, including 80 protein-coding genes, 29 transfer RNAs, and 4 ribosomal RNAs. SSRs mainly consist of A/T repeats and AT/AT repeats, while INEs mainly consist of positive repeats and palindromic repeats. The frequency of codon usage was essentially the same, with a total of 31 high-frequency codons detected, the vast majority ending in A/U. Five mutation hotspots were detected: rps16-trnQ-UUG, ndhF, ccsA-ndhD, ycf1, and trnN-GUU, among which ycf1 had the highest Pi value and the greatest potential as a DNA barcode marker. Our phylogenetic tree shows that all 13 species belong to Section Impatiens. And supported the classification of I. reptans and I. rhombifolia should as synonyms (BS = 100/PP = 1.00). This study comprehensively analyzed the cp genomes of different taxa, sheds light on the taxonomic intricacies of Impatiens species, provide valuable information into its phylogenetic and taxonomy.

Rethinking Conservation and Restoration Strategies of Endangered and Key Medicinal Clavicarpa Plants in Yunnan-Kweichow Plateau's Karst Areas Under Climate Change

The Clavicarpa species, valued for their pharmaceutical, ornamental, and economic importance, exhibit notable rarity and endemism in the Karst areas of the Yunnan-Kweichow Plateau in China. These species face significant threats from habitat loss and fragmentation, leading to a decline in biodiversity. To mitigate these threats, the Maxent algorithm was employed to analyze current and future distribution patterns, with a particular focus on the influence of climate variables in predicting potential distribution shifts and assessing extinction risks under the optimistic SSP1-2.6 and the pessimistic SSP5-8.5 socioeconomic scenarios. The EC-Earth3-Veg, MRI-ESM2-0, and MPI-ESM1-2-HR models were utilized for conservation status assessment and project future distributions for four time periods: the present, 2030s, 2050s, and 2070s. The minimum temperature during the coldest month (Bio 6) was identified as the most critical environmental factor, influencing both habitat contraction and expansion. Our modeling indicates that regions such as South, Central, and East China, particularly areas east of the Aihui-Tengchong line and south of the Yangtze River, exhibit the highest suitability for Clavicarpa species within the geographical coordinates of 18° N-45° N and 97° E-120° E. Conversely, climate change projections suggest a habitat expansion for Impatiens claviger, Impatiens tubulosa, Impatiens pritzelii, and Impatiens apalophylla, while Impatiens guizhouensis and Impatiens wilsonii face increased extinction risks. Specifically, I. claviger, I. tubulosa, and I. apalophylla are expected to shift northward, necessitating potential relocation to southern regions, while I. guizhouensis and I. wilsonii are projected to experience habitat losses of over 23.94% and 9.13%, respectively. Our research provides a robust scientific foundation for the conservation and sustainable utilization of these important pharmaceutical species and offers a framework for effective biodiversity management. We recommend using protected areas as a basis for the future conservation, breeding, cultivation, and utilization of Clavicarpa species.

Exploring the phylogenetic framework and trait evolution of Impatiens through chloroplast genome analysis

BACKGROUND

The genus Impatiens, which includes both annual and perennial herbs, holds considerable ornamental, economic, and medicinal value. However, it posed significant challenges for taxonomic and systematic reconstruction. This was largely attributed to its high intraspecific diversity and low interspecific variation in morphological characteristics. In this study, we sequenced samples from 12 Impatiens species native to China and assessed their phylogenetic resolution using the complete chloroplast genome, in conjunction with published samples of Impatiens. In addition, a comparative analysis of chloroplast genomes were conducted to explore the evolution of the chloroplast genome in Impatiens.

RESULTS

The chloroplast genomes of 12 Impatiens species exhibited high similarity to previously published samples in terms of genome size, gene content, and sequence. The chloroplast genome of Impatiens exhibited a typical four-part structure, with lengths ranging from 146,987 bp(I. morsei)- 152,872 bp(I. jinpingensis). Our results identified 10 mutant hotspot regions (rps16, rps16-trnG, trnS-trnR, and rpoB-trnC) that could serve as effective molecular markers for phylogenetic analyses and species identification within the Impatiens. Phylogenetic analyses supported the classification of Impatiens as a monophyletic taxon. The identified affinities supported the taxonomic classification of the subgenus Clavicarpa within the Impatiens, with subgenus Clavicarpa being the first taxon to diverge. In phylogenetic tree,the Impatiens was divided into eight distinct clades. The results of ancestral trait reconstruction suggested that the ancestral traits of Impatiens included a perennial life cycle, four sepals and three pollen grooves. However, the ancestral morphology regarding fruit shape, flower colour, and spacing length remained ambiguous.

CONCLUDE

Our study largely supported the family-level taxonomic treatment of Impatiens species in China and demonstrated the utility of whole chloroplast genome sequences for phylogenetic resolution. Comparative analysis of the chloroplast genomes of Impatiens facilitated the development of molecular markers.The results of ancestral trait reconstruction showed that the ancestor type of habit was perennial, the number of sepals was 4, and morphology and number of aperture was 3 colpus. The traits of capsule shape, flower colour, and spur length underwent a complex evolutionary process. Our results provided data support for further studies and some important new insights into the evolution of the Impatiens.

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

Impatiens uliginosa is a plant of the Impatiens, with peculiar flowers. In this study, we combined morphogenesis and molecular biology to explore its development of flowers. An analysis of basic observational data and paraffin sectioning showed that it took approximately 13 d for the floral organs to differentiate. An analysis of the development of inflorescences and floral organs by scanning electron microscopy showed that the inflorescence of I. uliginosa is a spiral raceme. The floral organs differentiated in the following order: lateral sepals (Ls), posterior sepal (Ps), anterior sepals (As), anterior petal (Ap), lateral petals (Lp), stamens (St) and gynoecium (Gy). I. uliginosa was found to have four sepals, and the connate stamens are caused by the fusion and growth of filament appendages. The results of fluorescence quantification and virus-induced gene silencing showed that I. uliginosa had its own unique model for flower development, and there was functional diversity of IuAP1 and IuDEF. Among them, IuAP1 controls the formation of bract s (Br), regulates the morphogenesis of posterior sepal, controls the anthocyanin precipitation of the anterior petals and the formation of lateral petals. IuDEF regulates the morphogenesis of lateral sepals, the length of development of the spur, and controls the size of yellow flower color plaques of the lateral petals. In this study, the process of flower development and the function of flower development genes of I. uliginosa were preliminarily verified. This study provides basic guidance and new concepts that can be used to study the development of Impatiens flowers.

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

Introduction

The potential contamination of herbal medicinal products poses a significant concern for consumer health. Given the limited availability of genetic information concerning Ajuga species, it becomes imperative to incorporate supplementary molecular markers to enhance and ensure accurate species identification.

Methods

In this study, the chloroplast (cp) genomes of seven species of the genus Ajuag were sequenced, de novo assembled and characterized.

Results

exhibiting lengths ranging from 150,342 bp to 150,472 bp, encompassing 86 - 88 protein-coding genes (PCGs), 35 - 37 transfer RNA, and eight ribosomal RNA. The repetitive sequences, codon uses, and cp genomes of seven species were highly conserved, and PCGs were the reliable molecular markers for investigating the phylogenetic relationship within the Ajuga genus. Moreover, four mutation hotspot regions (accD-psaI, atpH-atpI, ndhC-trnV(UAC), and ndhF-rpl23) were identified within cp genomes of Ajuga, which could help distinguish A. bracteosa and its contaminants. Based on cp genomes and PCGs, the phylogenetic tree preliminary confirmed the position of Ajuga within the Lamiaceae family. It strongly supported a sister relationship between Subsect. Genevense and Subsect. Biflorae, suggesting the merger of Subsect. Biflorae and Subsect. Genevenses into one group rather than maintaining separate categorizations. Additionally, molecular clock analysis estimated the divergence time of Ajuga to be around 7.78 million years ago.

Discussion

The species authentication, phylogeny, and evolution analyses of the Ajuga species may benefit from the above findings.