Hai-Quan Huang

The Impatiens plants are one of the world’s top three flower bed floriferous plants with important ornamental and horticultural values, vivid floral

Background The Impatiens plants are one of the world's top three flower bed floriferous plants with important ornamental and horticultural values, vivid floral colors are more likely to attract pollinators, and one of the important ornamental traits of flowers. This study was conducted to determine whether the flower color of Impatiens can be altered after induction, with the aim of clarifying the molecular basis underlying its variation and to offer a vital reference for developing novel Impatiens varieties. Compared with diploids, the flower color of colchicine-induced Impatiens showed obvious changes, the flowers changed from pinkish purple to orange. Results Integrated metabolomics and transcriptomics were comprehensively utilized to reveal the metabolic pathways of anthocyanin biosynthesis in non-mutant purple flowers and mutant orange. The floral hue discrepancies between Ih-WT and Ih-MU in Impatiens hybrida ‘Solarscape’ exhibit marked variations in luminance (L*), the red-green axis (a*), the yellow-blue axis (b*), and color intensity (Chroma c*). Specifically, the L* value of Ih-WT is significantly higher than that of Ih-MU, and the a*, b*, and Chroma c* values of Ih-WT are significantly greater than those of Ih-MU. Metabolomics identified 93 differential metabolites, most of which were Cyanidin and Pelargonidin-like metabolites, and the accumulation of Cyanidin and Pelargonidin was the principal factor underlying the petal color transition to orange in I. hybrida 'Solarscape'. The accumulation of Cyanidin and Pelargonidin was the main reason for the orange coloration of I. hybrida 'Solarscape' petals. Comparative analysis of the differential metabolites in the two flower samples indicated that the two anthocyanins, Pelargonidin-3-O-sophoroside and Cyanidin-3-O-sophoroside, were the pigments most likely to regulate petal coloration. Analysis of the transcriptome identified 1888 differentially expressed genes (DEGs), including key genes for anthocyanin synthesis (IhC4H, IhUFGT, IhDFR, and IhANS) and regulators (IhMYB308, IhNAC56, and IhMYC2) with high levels of expression of Ih-MU in orange flowers, indicating that they play a role in the regulation of anthocyanin biosynthesis. These genes may be pivotal for the biosynthesis of orange anthocyanins. Co-expression analysis of differentially expressed genes and the relative levels of differentially expressed anthocyanins revealed that each anthocyanin is strongly associated with multiple genes, indicating that the anthocyanin accumulation process is governed by multiple genes. The expression levels of these genes exhibited a statistically significant positive correlation with the relative concentrations of Pelargonidin-3-O-sophoroside, Cyanidin-3-O-(6-O-p-coumaroyl)-glucoside, and Cyanidin-3-O-sophoroside. Conclusions This study showed substantial alterations in color and anthocyanin synthesis in chemically mutagenized I. hybrida 'Solarscape' flowers, and these findings could provide some insight into the relationship between Impatiens and other flowers could offer a theoretical foundation for the breeding improvement of Impatiens and other flowers. Keywords: Impatiens hybrida 'Solarscape'; floral color variation; metabolomics; transcriptomics; anthocyanin biosynthesis

The phytoremediation of soil and water that has been significantly contaminated with metals has potential ecological and economical ramifications, as well as the advantages of high efficiency, and is an environmentally friendly method of ecological pollution control. This study aimed to examine the impact of varying concentrations of Copper (Cu²⁺) (0, 5, 10, 15, 20, and 25 mg·L⁻¹) on the growth, development, physiology, biochemistry, mineral elements, and features of Cu²⁺ enrichment of Impatiens uliginosa. This plant is endemic to Yunnan Province in China and is a wetland species. The results showed that the root lengths, stem diameters, plant height, and stem and leaf biomass of I. uliginosa showed a phenomenon of “low promotion and high inhibition,” while the root biomass showed a trend of gradual decreasing. At the early stage of Cu²⁺ stress (day 6), the activities of peroxidase and catalase and the contents of malondialdehyde (MDA) of I. uliginosa were directly proportional to the concentration of Cu²⁺. As the treatment time increased, the activation of a defense mechanism in vivo enabled I. uliginosa to adapt to the high Cu²⁺ environment, and the content of MDA gradually decreased. As the concentration of Cu²⁺ increased, its contents in the roots, stems, and leaves also gradually increased. In particular, when the concentration of Cu²⁺ reached 25 mg·L⁻¹, its contents in the roots of I. uliginosa increased by 39.16-fold compared with that of the control group (CK). The concentration-dependent influence of the contents of iron (Fe) and zinc (Zn) in the roots and leaves were observed. Low concentrations of Cu²⁺ promoted iron content in roots and leaves, and vice versa, while Zn content decreased with the increasing concentration of Cu²⁺. It was conclusively shown that I. uliginosa has the potential to remediate low concentrations of Cu²⁺ pollution in water and is a textbook ornamental plant to remediate bodies of water that are polluted with Cu²⁺.

Background: Impatiens is an important genus with rich species of garden plants, and its distribution is extremely extensive, which is reflected in its diverse ecological environment. However, the specific mechanisms of Impatiens’ adaptation to various environments and the mechanism related to lignin remain unclear. Results: Three representative Impatiens species,Impatiens chlorosepala (wet, low degree of lignification), Impatiens uliginosa (aquatic, moderate degree of lignification) and Impatiens rubrostriata (terrestrial, high degree of lignification), were selected and analyzed for their anatomical structures, lignin content and composition, and lignin-related gene expression. There are significant differences in anatomical parameters among the stems of three Impatiens species, and the anatomical structure is consistent with the determination results of lignin content. Furthermore, the thickness of the xylem and cell walls, as well as the ratio of cell wall thickness to stem diameter have a strong correlation with lignin content. The anatomical structure and degree of lignification in Impatiens can be attributed to the plant's growth environment, morphology, and growth rate. Our analysis of lignin-related genes revealed a negative correlation between the MYB4 gene and lignin content. The MYB4 gene may control the lignin synthesis in Impatiens by controlling the structural genes involved in the lignin synthesis pathway, such as HCT, C3H, and COMT. Nonetheless, the regulation pathway differs between species of Impatiens. Conclusions: This study demonstrated consistency between the stem anatomy of Impatiens and the results obtained from lignin content and composition analyses. It is speculated that MYB4 negatively regulates the lignin synthesis in the stems of three Impatiens species by regulating the expression of structural genes, and its regulation mechanism appears to vary across different Impatiens species. This study analyses the variations among different Impatiens plants in diverse habitats, and can guide further molecular investigations of lignin biosynthesis in Impatiens.

Impatiens uliginosa is a native and potential water body-restoring ornamental plant. In this study, RNA-Seq technology was used to analyze the transcriptome of its floral organs. Candidate genes related to flower color changes under copper stress were investigated through transcriptome screening, and the intrinsic mechanism of the effects of different concentrations of copper on I. uliginosa was revealed at the molecular level. The main findings were as follows: (1) Transcriptome sequencing analysis was performed on the flower organs of I. uliginosa treated with different concentrations of copper (0 mg·L⁻¹, 10 mg·L⁻¹, and 20 mg·L⁻¹). A total of 70,319 transcripts and 39,949 unigenes were obtained. An analysis of differentially expressed genes revealed structural genes including GT, ANS, CHI, and PAL; transcription factors including MYB and WD40; and transport factors including GST and ABC. (2) The gene expression levels of flower color changed in the flowering period of I. uliginosa at different copper concentrations. The expression levels of IuGT and IuGST genes in I. uliginosa were significantly different under different concentrations of copper treatments. Their expression levels were the highest at a copper concentration of 0 mg·L⁻¹ and the lowest at 20 mg·L⁻¹. In summary, the low expression of IuGT and IuGST genes was more conducive to the formation of white flowers of I. uliginosa.

Introduction: Flower color is one of the important ornamental traits in the plants, which plays an active role in attracting pollinators to pollinate plants and reproduce their offspring. The flower color of Impatiens uliginosa is rich, there are four main flower colors in nature: deep red, red, pink, and white. However, it remains unclear whether on four different flower colors mechanism of I. uliginosa.Methods: We investigate colorimetric measurement, observation of epidermal cells, cellular pH determination, extraction and determination of total anthocyanins and flavonoid, semi-quantitative determination of pigment components, and gene cloning and qRT-PCR of CHS genes to study four flower colors of I. uliginosa.Results: The L^* and b^* values were the highest in white flower, while the a^* values were the highest in pink flower. The same shape of epidermal cells was observed in different flower colors, which was all irregular flat polygons, and there were partial lignification. Their cellular pH values were weakly acidic, while the pH values of the deep red flower was the highest and the white flower was the lowest. The highest pigment content of the four flower colors was total anthocyanin content. And malvidin-3-galactosidechloride (C₂₃H₂₅ClO₁₂), cyanidin-3-O-glucoside (C₂₁H₂₁O₁₁) and delphinidin (C₁₅H₁₁O₇) were the main pigment components affecting the color of four different flower colors. The anthocyanin synthesis gene IuCHS was expressed in four flowers, and all three copies of it had the highest expression level in pink flower and the lowest expression level in white flower.Discussion: These results revealed the influence of main internal factors on four different flower colors of I. uliginosa, and provided a basis for further understanding of the intracellular and molecular regulatory mechanisms of flower color variation, and laid a foundation for the improvement of flower color breeding of Impatiens.

Impatiens L. is a genus of complex taxonomy that belongs to the family Balsaminaceae (Ericales) and contains approximately 1000 species. In this study, ISSR, trnL-trnnF, atpB-rbcL and DEF four molecular markers were used to analyze the genetic diversity and phylogenetic relationships among 32 species of Impatiens from eastern Yunnan. The results showed that the genetic similarity coefficient (GS) of these Impatiens resources ranged from 0.540 to 0.990, it indicated that the genetic diversity was relatively rich. However the genetic distance was relatively vague, and the evolutionary relationship was not obvious, which the phylogenetic trees were constructed by using the chloroplast genes atpB-rbcL and trnL-trnF. The genetic distance of the phylogenetic tree constructed by the DEF gene was relatively clear, the evolutionary relationship was obvious, and the result was consistent with ISSR. This indicated that DEF gene was greatly affected by plant habitat, and had abundant variation and a fast evolution rate, while atpB-rbcL and trnL-trnF genes had a slower evolution rate. And it was discovered that the flower morphological traits of the genus Impatiens can be employed as significant categorization markers. In particular, the wing shape can be used as an important flower morphological feature for the classification of the genus Impatiens in eastern Yunnan; and the results of using ISSR and DEF gene markers and flower morphological characteristics were consistent with the results of the interspecies division of Impatiens in this region. This study provided new basic data and a scientific basis for the protection, sustainable development, and utilization of Impatiens plant resources and genetic breeding in this region.

Background: Spur, a structure capable of producing and storing nectar, not only plays a vital role in the pollination process but also promotes the rapid diversification of some plant lineages, which is considered a key innovation in plants. Spur is the focus of many studies, such as evolution and ecological hypothesis, but the current understanding of spur development is limited. High-throughput sequencing of Impatiens uliginosa was carried out to study the molecular mechanism of its spur development, which is believed to provide some insights into the spur development of Impatiens. Results: Transcriptomic sequencing and analysis were performed on spurs and limbs of I. uliginosa at three developmental stages. A total of 47.83 Gb of clean data were obtained, and 49,716 unigene genes were assembled. After comparison with NR, Swiss-Prot, Pfam, COG, GO and KEGG databases, a total of 27,686 genes were annotated successfully. Through comparative analysis, 19,356 differentially expressed genes were found and enriched into 208 GO terms and 146 KEGG pathways, among which plant hormone signal transduction was the most significantly enriched pathway. One thousand thirty-two transcription factors were identified, which belonged to 33 TF families such as MYB, bHLH and TCP. Twenty candidate genes that may be involved in spur development were screened and verified by qPCR, such as SBP, IAA and ABP. Conclusions: Transcriptome data of different developmental stages of spurs were obtained, and a series of candidate genes related to spur development were identified. The importance of genes related to cell cycle, cell division, cell elongation and hormones in spur development was clarified. This study provided valuable information and resources for understanding the molecular mechanism of spur development in Impatiens.

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.