Nutrient availability and plant phenological stage influence the substrate microbiome in container-grown Impatiens walleriana 'Xtreme Red'

BACKGROUND

The microbiome plays a fundamental role in plant health and performance. Soil serves as a reservoir of microbial diversity where plants attract microorganisms via root exudates. The soil has an important impact on the composition of the rhizosphere microbiome, but greenhouse ornamental plants are commonly grown in soilless substrates. While soil microbiomes have been extensively studied in traditional agriculture to improve plant performance, health, and sustainability, information about the microbiomes of soilless substrates is still limited. Thus, we conducted an experiment to explore the microbiome of a peat-based substrate used in container production of Impatiens walleriana, a popular greenhouse ornamental plant. We investigated the effects of plant phenological stage and fertilization level on the substrate microbiome.

RESULTS

Impatiens plants grown under low fertilization rates were smaller and produced more flowers than plants grown under optimum and high fertilization. The top five bacterial phyla present in the substrate were Proteobacteria, Actinobacteria, Bacteriodota, Verrucomicrobiota, and Planctomycetota. We found a total of 2,535 amplicon sequence variants (ASV) grouped into 299 genera. The substrate core microbiome was represented by only 1.8% (48) of the identified ASV. The microbiome community composition was influenced by plant phenological stage and fertilizer levels. Phenological stage exhibited a stronger influence on microbiome composition than fertilizer levels. Differential abundance analysis using DESeq2 identified more ASVs significantly affected (enriched or depleted) in the high fertilizer levels at flowering. As observed for community composition, the effect of plant phenological stage on microbial community function was stronger than fertilizer level. Phenological stage and fertilizer treatments did not affect alpha-diversity in the substrate.

CONCLUSIONS

In container-grown ornamental plants, the substrate serves as the main microbial reservoir for the plant, and the plant and agricultural inputs (fertilization) modulate the microbial community structure and function of the substrate. The differences observed in substrate microbiome composition across plant phenological stage were explained by pH, total organic carbon (TOC) and fluoride, and across fertilizer levels by pH and phosphate (PO4). Our project provides an initial diversity profile of the bacteria occurring in soilless substrates, an underexplored source of microbial diversity.

Pollen wall development in Impatiens glandulifera: exine substructure and underlying mechanisms

The aim of this study was to investigate in detail the pollen wall ontogeny in Impatiens glandulifera, with emphasis on the substructure and the underlying mechanisms of development. Sporopollenin-containing pollen wall, the exine, consists of two parts, ectexine and endexine. By determining the sequence of developing substructures with TEM, we have in mind to understand in which way the exine substructure is connected with function. We have shown earlier that physical processes of self-assembly and phase separation are universally involved in ectexine development; currently, we try to clear up whether these processes participate in endexine development. The data received were compared with those on other species. The ectexine ontogeny of I. glandulifera followed the main stages observed in many other species, including the late tetrad stage named "Golden gates". It turned out that the same physico-chemical processes act in endexine development, especially expressed in aperture sites. Another peculiar phenomenon observed in exine development was the recurrency of micellar sequence at near-aperture and aperture sites where the periplasmic space is widened. It should be noted that, in the whole, the developmental substructures observed during the tetrad and early post-tetrad period are similar in species with columellate exines. Evidently, these basic physical processes proceed, reiterating again and again in different species, resulting in an enormous variety of exine structures on the base of a relatively modest number of genes. Granular and alveolar exines emerge on the base of the same basic processes but are arrested at spherical and cylindrical micelle mesophases correspondingly.

Benzylisoquinoline alkaloids with their antitumor activity from the aerial parts of Corydalis impatiens (pall.) Fisch

Phytochemical investigation on the aerial parts of Corydalis impatiens (pall.) Fisch (Papaveraceae) resulted in the identification of four previous undescribed benzylisoquinoline alkaloids, impatienines A-D (1-4), together with 14 known analogues (5-18). The structures of these compounds were elucidated by extensive spectroscopic analysis (IR, HR-ESIMS, 1D- and 2D-NMR) as well as ECD calculations. All the compounds obtained were investigated for their inhibitory effect on the growth of A549, H1299 and HepG2 cancer cells. Compounds 7 and 15 exhibited pronounced inhibition against the A549 cancer cells with IC50 values of 6.81 μM and 3.17 μM, while the positive control cisplatin was 1.83 μM. Compounds 1-3 showed moderate inhibitory on the H1299 cancer cells. Compounds 4, 10-12, and 16 showed signiffcant activity against HepG2 cancer cells with IC50 values range of 4.41-8.75 μM.

Past climate cooling and orogenesis of the Hengduan Mountains have influenced the evolution of Impatiens sect. Impatiens (Balsaminaceae) in the Northern Hemisphere

BACKGROUND

Impatiens sect. Impatiens is distributed across the Northern Hemisphere and has diversified considerably, particularly within the Hengduan Mountains (HDM) in southwest China. Yet, the infra-sectional phylogenetic relationships are not well resolved, largely due to limited taxon sampling and an insufficient number of molecular markers. The evolutionary history of its diversification is also poorly understood. In this study, plastome data and the most complete sampling to date were used to reconstruct a robust phylogenetic framework for this section. The phylogeny was then used to investigate its biogeographical history and diversification patterns, specifically with the aim of understanding the role played by the HDM and past climatic changes in its diversification.

RESULTS

A stable phylogeny was reconstructed that strongly supported both the monophyly of the section and its division into seven major clades (Clades I-VII). Molecular dating and ancestral area reconstruction suggest that sect. Impatiens originated in the HDM and Southeast China around 11.76 Ma, after which different lineages dispersed to Northwest China, temperate Eurasia, and North America, mainly during the Pliocene and Pleistocene. An intercontinental dispersal event from East Asia to western North America may have occurred via the Bering Land Bridge or Aleutian Islands. The diversification rate was high during its early history, especially with the HDM, but gradually decreased over time both within and outside the HDM. Multiple linear regression analysis showed that the distribution pattern of species richness was strongly associated with elevation range, elevation, and mean annual temperature. Finally, ancestral niche analysis indicated that sect. Impatiens originated in a relatively cool, middle-elevation area.

CONCLUSIONS

We inferred the evolutionary history of sect. Impatiens based on a solid phylogenetic framework. The HDM was the primary source or pump of its diversity in the Northern Hemisphere. Orogeny and climate change may have also shaped its diversification rates, as a steady decrease in the diversification rate coincided with the uplift of the HDM and climate cooling. These findings provide insights into the distribution pattern of sect. Impatiens and other plants in the Northern Hemisphere.

De-novo whole genome assembly of the orange jewelweed, Impatiens capensis Meerb. (Balsaminaceae) using nanopore long-read sequencing

The plant family Balsaminaceae comprises only two genera, and they are a study in contrasts. While Impatiens is an impressively prolific genus, with over 1,000 species and more being discovered each year, its sister genus, Hydrocera, has one solitary species, H. triflora. The two genera also differ in geographic distribution and habitat type (Impatiens species are widely distributed in much of the Old World and N. America, while H. triflora is confined to wetlands specific to S. India, Sri Lanka, and SE Asia). Other contrasting features include plant habit, habitat, floral architecture, mode of seed dispersal, and a host of other traits. The family Balsaminaceae is therefore an excellent model for studying speciation and character evolution as well as understanding the proximal and evolutionary forces that have driven the two genera to adopt such contrasting evolutionary paths. Various species of the Impatiens genus are also commercially important in the ornamental flower industry and as sources of phytochemicals that are of medicinal and other commercial value. As a preliminary step towards studying the genomic basis of the contrasting features of the two genera, we have sequenced and assembled, de novo, the genome of an iconic Impatiens species from N. America, namely I. capensis, and report our findings here.

Antioxidant activity and mineral content of Impatiens tinctoria A. Rich (Ensosila) tuber, an Ethiopian medicinal plant

Recently, an interest has surged in incorporating extracts of medicinal plants as active ingredients in cosmetic formulations, highlighting the need to analyze medicinal plants of cosmetic interest for phytochemicals and bioactivities. The tuber of the Ethiopian medicinal plant Impatiens tinctoria A. Rich (Ensosila) is used to make traditional cosmetics. The aim of the study was to investigate the antioxidant and mineral content of the Impatiens tinctoria tuber. Water, ethanol, and methanol were used during the extraction process. High phenolic content was found in methanol extract (107.8 ± 0.025 µg/ml GAE) followed by water extract (92.4 ± 0.02 µg/ml GAE). High flavonoid content was also obtained in methanol extract (136.7 ± 0.04 µg/ml QE). Strong 2,2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity was recorded for methanol extract with IC50 value of 44.4 µg/ml, compared with ethanol extract (97.54 µg/ml) and water extracts (98.24 µg/ml). The lower IC50 value of methanolic extract demonstrated strong antioxidant activity. The three elements that were most prevalent in Impatiens tinctoria tuber out of the eight elements examined were K (170 ± 0.05 mg/100 g sample), Ca (87 ± 0.08 mg/100 g sample), and Mg (16 ± 0.01 mg/100 g sample). The phenolics, flavonoids, and minerals found in Impatiens tinctoria A. Rich (Ensosila) tuber may protect against oxidative stress-related skin damage and thus deserving attention for future applications in cosmetics formulations.

Sympatric co-existence of two ecotypes of Impatiens noli-tangere (Balsaminaceae) with different morphology and flowering phenology

In angiosperms, intraspecific variation of flowering phenology may affect reproductive isolation and, consequently, speciation. This study focused on Impatiens noli-tangere (Balsaminaceae), which is distributed over broad latitudinal and altitudinal ranges in Japan. We aimed to reveal the phenotypic mixture of two ecotypes of I. noli-tangere with different flowering phenology and morphological traits in a narrow contact zone. Previous studies have shown that I. noli-tangere has early- and late-flowering types. The early-flowering type makes buds in June and is distributed at high-elevation sites. The late-flowering type makes buds in July and is distributed at low-elevation sites. In this study, we analyzed the flowering phenology of individuals at an intermediate elevation site where the early- and late-flowering types grow in sympatry (contact zone). We found no individuals showing intermediate flowering phenology at the contact zone, and early- and late-flowering types were clearly distinguishable. We also found that the differences in many other phenotypic traits between the early- and late-flowering types were maintained, including the number of flowers produced (total number of chasmogamous and cleistogamous flowers), leaf morphology (aspect ratio, number of serrations), seed traits (aspect ratio), and flower bud formation positions on the plant. This study showed that these two flowering ecotypes maintain many different traits in sympatry.

Impatiens balsamina: An updated review on the ethnobotanical uses, phytochemistry, and pharmacological activity

ETHNOPHARMACOLOGICAL RELEVANCE

Impatiens balsamina is an annual herb of the Balsaminaceae family, which is cultivated extensively in Asia as an ornamental plant. Notably, as a folk medicine, I. balsamina has been long prescribed for the treatment of rheumatism, isthmus, generalized pain, fractures, inflammation of the nails, scurvy, carbuncles, dysentery, bruises, foot diseases, etc. AIM OF THE STUDY: The paper overviews comprehensive information on ethnobotanical uses, phytochemistry, pharmacological activity, and toxicity of I. balsamina, aiming at laying a sturdy foundation for further development of I. balsamina.

MATERIALS AND METHODS

Research information was acquired through electronic databases such as Web of Science, PubMed, SciFinder, ScienceDirect, Google Scholar, and CNKI with the keyword "Impatiens balsamina ".

RESULTS

Briefly, more than 307 natural compounds have been separated and identified from various medicinal parts of I. balsamina, which are classified into diverse groups, like flavonoids, naphthoquinones, coumarins, terpenoids, sterols, phenols, fatty acids and their ester, naphthalene derivatives, nitrogen-containing compounds, polysaccharides, and other compounds. In particular, 2-methoxy-1,4-naphthoquinone, one of the naphthoquinones, is the predominant and most representative component. Moreover, I. balsamina furnishes numerous and complicated pharmacological activities, including antimicrobial, antiallergic, antipruritic, antitumor, antioxidant, anti-inflammatory, immunomodulatory, anti-hepatic fibrosis, insecticidal, and anthelmintic as well as enzyme-inhibiting activities, etc. Toxicological studies have shown that the hexane extract of the stems and leaves was less toxic, and the hydroalcoholic extract of stems was more toxic.

CONCLUSIONS

The paper contributes to updating the ethnobotanical uses, phytochemistry, pharmacological activity, and toxicity of I. balsamina, which offer abundant information for future investigations and applications of I. balsamina.

Allelochemical run-off from the invasive terrestrial plant Impatiens glandulifera decreases defensibility in Daphnia

Invasive species are a major threat for native ecosystems and organisms living within. They are reducing the biodiversity in invaded ecosystems, by outcompeting native species with e. g. novel substances. Invasive terrestrial plants can release allelochemicals, thereby reducing biodiversity due to the suppression of growth of native plants in invaded habitats. Aside from negative effects on plants, allelochemicals can affect other organisms such as mycorrhiza fungi and invertebrates in terrestrial ecosystems. When invasive plants grow in riparian zones, it is very likely that terrestrial borne allelochemicals can leach into the aquatic ecosystem. There, the often highly reactive compounds may not only elicit toxic effects to aquatic organisms, but they may also interfere with biotic interactions. Here we show that the allelochemical 2-methoxy-1,4-naphthoquinone (2-MNQ), produced by the ubiquitously occurring invasive terrestrial plant Impatiens glandulifera, interferes with the ability of Daphnia to defend itself against predators with morphological defences. Daphnia magna and Daphnia longicephala responded with morphological defences induced by chemical cues released by their corresponding predators, Triops cancriformis or Notonecta sp. However, predator cues in combination with 2-MNQ led to a reduction in the morphological defensive traits, body- and tail-spine length, in D. magna. In D. longicephala all tested inducible defensive traits were not significantly affected by 2-MNQ but indicate similar patterns, highlighting the importance to study different species to assess the risks for aquatic ecosystems. Since it is essential for Daphnia to adapt defences to the current predation risk, a maladaptation in defensive traits when simultaneously exposed to allelochemicals released by I. glandulifera, may therefore have knock-on effects on population dynamics across multiple trophic levels, as Daphnia is a key species in lentic ecosystems.

Contradictory effect of climate change on American and European populations of Impatiens capensis Meerb. - is this herb a global threat?

AIMS

The present study is the first-ever attempt to generate information on the potential present and future distribution of Impatiens capensis (orange balsam) under various climate change scenarios. Moreover, the differences in bioclimatic preferences of native and non-native populations were evaluated.

LOCATION

Global.

TAXON

Angiosperms.

METHODS

A database of I. capensis localities was compiled based on the public database - the Global Biodiversity Information Facility (GBIF), herbarium specimens, and a field survey in Poland. The initial dataset was verified, and each record was assigned to one of two groups - native (3664 records from North America) or non-native (750 records from Europe and the western part of North America). The analyses involved bioclimatic variables in 2.5 arc-minutes of interpolated climate surface downloaded from WorldClim v. 2.1. MaxEnt version 3.3.2 was used to conduct the ecological niche modeling based on presence-only observations of I. capensis. Forecasts of the future distribution of the climatic niches of the studied species in 2080-2100 were made based on climate projections developed by the CNRM/CERFACS modeling and Model for Interdisciplinary Research on Climate (MIROC-6).

MAIN CONCLUSIONS

Distribution models created for "present time" showed slightly broader potential geographical ranges of both native and invasive populations of orange balsam. On the other hand, some areas (e.g. NW Poland, SW Finland), settled by the species, are far outside the modeled climate niche, which indicates a much greater adaptation potential of I. capensis. In addition, the models have shown that climate change will shift the native range of orange balsam to the north and the range of its European populations to the northwest. Moreover, while the coverage of niches suitable for I. capensis in America will extend due to climate change, the European populations will face 31-95 % habitat loss.

De novo transcriptome sequencing of Impatiens uliginosa and the analysis of candidate genes related to spur development

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.

A new species of Impatiens and updated checklist of Balsaminaceae in Nepal

Impatiens nimspurjae (Impatiens, Balsaminaceae), a new species from Nepal is described based on molecular data and morphological characters. Notes on the diagnostic characters used to distinguish it from allied taxa are provided. I. nimspurjae is closely related with taxon belonging to sect. Racemosae (I. harae, I. radiata, I. wallichii, I. urticifolia) in having many-flowered racemose inflorescences, lateral sepals 2 (very rarely 4 with inner 2 reduced), capsule linear, seed ovoid, but differs by its sessile leaves, upper lobe of lower united petal not truncated, spur flattened at base. With the discovery of this new species and five species new records to Nepal, a checklist of Balsaminaceae having 57 species (8 endemic) in Nepal is updated. An identification key to the species of Imaptiens in Nepal is also provided.

Role of enemy release and hybridization in the invasiveness of Impatiens balfourii and I. glandulifera

Comparative studies with taxonomically and geographically paired alien species that exhibit different degrees of success in their invasions may help to identify the factors that determine invasiveness. Examples of such species in Europe include the noninvasive Impatiens balfourii and invasive I. glandulifera. We tested whether the low invasiveness of I. balfourii in Europe may be explained by strong pressure from local enemies. Earlier studies of these two species provided support for their hybridization. We tested this phenomenon as the potential occurrence of I. glandulifera × I. balfourii hybrids might promote the evolution of the invasiveness of I. balfourii. Both species were germinated from seeds collected in 2015 on the Swiss-Italian border in Insubria and utilized in three experiments: (1) a common garden enemy release test (leaf damage or pest pressure), (2) a test of the pressure exerted by a generalist enemy and (3) hybridization test. In the first test, the effect of enemies was assessed by the level of leaf damage and the number of pests. In the second test, a food choice experiment with a generalist herbivore (Cepaea snails) was performed. In the hybridization test, the plants were placed in a climatic chamber for self-pollination and hand cross-pollination. Analyses of enemy release and Cepaea snail preference revealed that I. balfourii experienced higher enemy pressure than I. glandulifera; however, this was not reflected in the performance of the plants. Although I. glandulifera was larger, I. balfourii had greater fecundity. Thus, the invasion success of I. glandulifera could not be unambiguously attributed to its greater degree of release from enemies compared with the noninvasive I. balfourii. Additionally, we did not obtain any evidence of hybridization between the two species. Thus, we obtained no support for the hypothesis that the evolution of the invasiveness of I. balfourii could be enhanced through hybridization with I. glandulifera.

Fast and Reproducible 96-Well Plate-Based Method for the Evaluation of the Antigerminative Potential of Plant Extracts and Phytotoxic Compounds

With the aim of evaluating the antigerminative activity of plant extracts, a miniaturized assay using 96-well plates (WP assay) was developed and compared to the long-established assay using Petri dishes (PD assay). The WP assay yielded results comparable to those of the PD assay using an ethanolic extract of the Himalayan balsam and lawsone as a standard. It also allowed the needed volume of the test solution to be cut by half and the number of required cress seeds to be cut by more than 1.5. The WP assay was then successfully applied to various extracts of Himalayan balsam, molecules (2,4-dichlorophenoxyacetic acid (2,4-D), glyphosate, and 2-methoxy-1,4-naphthoquinone (2-MNQ)) and target seeds (radish, lettuce, and wheat). By being adapted to a 96-well plate format, the antigerminative WP assay is a promising alternative to the PD assay. Besides, its convenience and low resource consumption make it ready for accelerated and high-throughput screening, as well as automation.

Plastic and quantitative genetic divergence mirror environmental gradients among wild, fragmented populations of Impatiens capensis

PREMISE

Habitat fragmentation generates molecular genetic divergence among isolated populations, but few studies have assessed phenotypic divergence and fitness in populations where the genetic consequences of habitat fragmentation are known. Phenotypic divergence could reflect plasticity, local adaptation, and/or genetic drift.

METHODS

We examined patterns and potential drivers of phenotypic divergence among 12 populations of jewelweed (Impatiens capensis) that show strong molecular genetic signals of isolation and drift among fragmented habitats. We measured morphological and reproductive traits in both maternal plants within natural populations and their self-fertilized progeny grown together in a common garden. We also quantified environmental divergence between home sites and the common garden.

RESULTS

Populations with less molecular genetic variation expressed less maternal phenotypic variation. Progeny in the common garden converged in phenotypes relative to their wild mothers but retained among-population differences in morphology, survival, and reproduction. Among-population phenotypic variance was 3-10× greater in home sites than in the common garden for 6 of 7 morphological traits measured. Patterns of phenotypic divergence paralleled environmental gradients in ways suggestive of adaptation. Progeny resembled their mothers less as the environmental distance between their home site and the common garden increased.

CONCLUSIONS

Despite strong molecular signatures of isolation and drift, phenotypic differences among these Impatiens populations appear to reflect both adaptive quantitative genetic divergence and plasticity. Quantifying the extent of local adaptation and plasticity and how these covary with molecular and phenotypic variation help us predict when populations may lose their adaptive capacity.

Mitochondrial Loci Enable Specific Quantitative Real-Time PCR Detection of the Pathogen Causing Contemporary Impatiens Downy Mildew Epidemics

Impatiens downy mildew (IDM) disease is a primary constraint on the production of Impatiens walleriana, a popular and economically important floriculture plant. IDM is caused by the biotrophic. oomycete Plasmopara destructor that emerged as a pathogen of I. walleriana in the 2000s. To enable P. destructor detection and quantification, a hydrolysis-probe-based quantitative PCR diagnostic assay was developed based on unique orientation and order of the mitochondrial cytochrome c oxidase subunit1 (cox1) and ATP synthase subunit alpha (atp1) genes in the genus Plasmopara. Nucleotide sequences and analysis of the cox1/atp1 region distinguished P. destructor and its sister-species P. obducens, consistent with prior phylogenetic analyses using cox2 and rDNA markers. Specificity for P. destructor was incorporated into a hydrolysis probe targeting the cox1 gene and flanking primers that amplified across the cox1/atp1 intergenic region. The limit of detection was 0.5 fg/μl of P. destructor DNA (∼100 plasmid copies/μl), with amplification efficiency = 0.95. The assay was validated against a panel of target and nontarget oomycetes, which showed that the primers were specific for Plasmopara spp., while the probe was specific for P. destructor infecting both I. walleriana and I. balsamina. Testing of Impatiens tissue collected from 23 locations across 13 states indicated all samples with IDM symptoms tested positive for P. destructor. Asymptomatic plants from two locations also tested positive for P. destructor.

Study on the Potential Application of Impatiens balsamina L. Flowers Extract as a Natural Colouring Ingredient in a Pastry Product

Flowers of the genus Impatiens are classified as edible; however, their inclusion in the human diet is not yet a common practice. Its attractive colours have stirred great interest by the food industry. In this sense, rose (BP) and orange (BO) I. balsamina flowers were nutritionally studied, followed by an in-depth chemical study profile. The non-anthocyanin and anthocyanin profiles of extracts of both flower varieties were also determined by high-performance liquid chromatography coupled to a diode array and mass spectrometry detector (HPLC-DAD-ESI/MS). The results demonstrated that both varieties presented significant amounts of phenolic compounds, having identified nine non-anthocyanin compounds and 14 anthocyanin compounds. BP extract stood out in its bioactive properties (antioxidant and antimicrobial potential) and was selected for incorporation in "bombocas" filling. Its performance as a colouring ingredient was compared with the control formulations (white filling) and with E163 (anthocyanins) colorant. The incorporation of the natural ingredient did not cause changes in the chemical and nutritional composition of the product; and although the colour conferred was lighter than presented by the formulation with E163 (suggesting a more natural aspect), the higher antioxidant activity could meet the expectations of the current high-demand consumer.

Multidirectional anti-melanoma effect of galactolipids (MGDG-1 and DGDG-1) from Impatiens parviflora DC. and their synergy with doxorubicin

The anti-melanoma potential of galactolipids: MGDG-1 and DGDG-1, isolated from Impatiens parviflora, and their synergistic effect with anticancer drug - doxorubicin (DOX) was investigated. Both compounds demonstrated time- and dose-dependent cytotoxicity against human melanoma cells of different metastatic potential. MGDG-1 was more effective than DGDG-1, with the highest activity against A375 cell line (IC₅₀ = 15.14 μg/mL). Both compounds acted selectively, were devoid of hepatotoxicity or mutagenicity. Additionally, MGDG-1 proved to be a tyrosinase inhibitor. Co-administration of MGDG-1 and DGDG-1 with DOX revealed a synergistic cytotoxic effect on melanoma cells. The cytotoxicity of all tested MGDG-1/DOX and DGDG-1/DOX cocktails was considerably higher than that of each agent administered alone. MGDG-1/DOX (Mix3) reduced the viability of A375 melanoma cells almost totally and this effect was 2-fold more potent as compared to DOX alone. Our study indicates that the overall effect is enhanced with the increasing concentration of MGDG-1 in the cocktail. These results open up a possibility for lowering therapeutic doses of chemotherapeutics such as doxorubicin when co-administrated with galactolipids. Thus, MGDG-1 can be prospectively considered as multidirectional anti-melanoma agent and can be recommended for further in vitro and in vivo studies, especially in search for effective combined therapy.

Complete Genome Sequence Resource for the Necrotrophic Plant-Pathogenic Bacterium Dickeya dianthicola 67-19 Isolated From New Guinea Impatiens

New Guinea impatiens (NGI, Impatiens hawkeri) are popular bedding plants that can be affected by a number of pathogens. Using 16S rDNA sequencing and genus-specific PCR, we identified the first Dickeya dianthicola strain isolated from NGI presented with blackleg symptoms, herein designated as D. dianthicola 67-19. Here, we report a high-quality complete and annotated genome sequence of D. dianthicola 67-19. The 4,851,809 bp genome was assembled with Nanopore reads and polished with Illumina reads, yielding 422× and 105× coverage, respectively. This closed genome provides a resource for future research on comparative genomics and biology of D. dianthicola, which could translate to improved detection and disease management.

Phytoremediation potential of Chromolaena odorata, Impatiens patula, and Gynura pseudochina grown in cadmium-polluted soils

To assess the cadmium (Cd) phytoremediation of three native plant species from Padeang zinc (Zn) mine area (Chromolaena odorata, Impatiens patula, and Gynura pseudochina), a hydroponic experiment was performed in nutrient solutions containing various concentrations of Cd (0, 5, 10, 20, and 50 mg L^-1) for 15 days. In the hydroponic experiment, C. odorata showed significantly higher total Cd content than those grown in 50 mg L^-1 Cd solutions. Only C. odorata and I. patula were chosen for the pot experiment. The plants were grown in spiked Cd-contaminated soils for 90 days, with different concentrations of Cd (0, 20, 40, 60, and 80 mg kg^-1). The results from the pot experiment revealed that both species accumulated more Cd in their root parts, with translocation factor values < 1. C. odorata exhibited the highest biomass production, relative growth rate, and Cd uptake or removal. The findings of the study clearly demonstrate the best uptake of C. odorata in Cd phytoremediation. Novelty statementEven though Chromolaena odorata, Impatiens patula, and Gynura pseudochina have been reported as a Cd accumulator but the assessment of these species by nutrient medium and the soil was not undertaken so far. The discovery of new Cd-accumulator plants has been hindered by the lack of efficient assessing. To assess the suitability of specific species of tropical plants that are able to uptake high amounts of Cd without risk of toxicity under conditions similar to the actual field study, is a novelty.

The readily transformable Impatiens walleriana efficiently attracts nectar feeding with Aedes and Culex mosquitoes in simulated outdoor garden settings in Mississippi and Florida

Mosquitoes rely upon plant nectars for their energy needs, a trait that has the potential to allow nectar to serve as a platform for producing and delivering toxins to nuisance and/or vector mosquito species. Impatiens walleriana (Order: Ericales, Family: Balsaminaceae) is a readily transformable and widely planted nectar plant that has been previously shown to attract mosquito nectar-feeding. However, those feeding studies were only conducted indoors and did not test if variable environmental conditions will affect nectar feeding. In this study, we tested incidence of nectar feeding from the extrafloral nectaries of I. walleriana with the mosquitoes Aedes aegypti, Ae. albopictus and Culex quinquefasciatus (Order: Diptera, Family: Culicidae) in simulated, outdoor garden settings in Mississippi and Florida. I. walleriana and other common garden plants (in a 1:4 ratio) were placed into a mesh-lined 4'x7' mesocosm along with 50 mosquitoes. To track nectar feeding, the nectar of I. walleriana was tagged with red dye and mosquitoes were analyzed for red dye fluorescence after feeding. Fluorescence analysis demonstrated that 81.9% of male and 86.6% of female mosquitoes fed on the nectar of I. walleriana within 24 h. This suggests that mosquitoes may readily feed on impatiens nectar in outdoor garden settings at temperate and semi-tropical sites, even when alternate common garden plants are available. This attraction capacity is essential for the further consideration of I. walleriana for development as a transgenic, mosquitocidal nectar plant.

Simulated pollinator declines intensify selection on floral traits that facilitate selfing and outcrossing in Impatiens capensis

PREMISE

Anthropogenic environmental change is causing pollinator populations to decline. These declines should intensify selection for floral traits that facilitate outcrossing by making plants more attractive to pollinators and/or for floral traits that facilitate selfing in the absence of pollinators. However, the effect of pollinator declines on selection on floral traits could be modified by other environmental factors such as herbivores.

METHODS

We studied the effect of simulated pollinator declines on selection on floral traits of Impatiens capensis, a mixed-mating species that produces both obligately selfing cleistogamous flowers and primarily outcrossing chasmogamous flowers. We measured directional selection differentials via seeds per plant on two traits that facilitate outcrossing (chasmogamous flower size and number) and one trait that facilitates selfing (cleistogamous flower number) in ambient, reduced pollinator access, and reduced pollinator access combined with increased foliar herbivory treatments.

RESULTS

Reduced pollinator access intensified selection for larger chasmogamous flowers and more cleistogamous flowers. In contrast, increased herbivory did not affect selection on any floral trait.

CONCLUSIONS

Reduced pollinator access intensified selection for a trait that facilitates outcrossing, suggesting that even species such as I. capensis that can autonomously self-pollinate have the potential to respond to pollinator declines by evolving floral traits that reinforce interactions between plants and pollinators. However, reduced pollinator access also intensified selection for a trait that facilitates selfing, suggesting that I. capensis could adapt to pollinator declines by evolving floral traits that maintain the production of both selfed and outcrossed seeds.

[Therapeutic effect of Impatiens balsamina, Lawsonia inermis L. and Henna on androgenetic alopecia in mice]

OBJECTIVE

To investigate the therapeutic effect of Impatiens balsamina, Lawsonia inermis L. and Henna in a C57BL/6 mouse model of androgenetic alopecia and explore the mechanisms.

METHODS

Forty-eight male C57BL/6 mice were randomized equally into blank control group, androgenetic alopecia model group, Impatiens balsamina group, Lawsonia inermis L. group, Henna group and minoxidil group. In all but those in the blank control group, the mice were subjected to dorsal subcutaneous injection of testosterone propionate solution (daily dose 5 mg/kg) to establish models of androgenetic alopecia and received subsequent treatment with topical application of the corresponding drugs on a daily basis for 35 days. The concentrations of testosterone, dihydrotestosterone and 5α reductase type Ⅱ in the serum and skin tissue were measured, and the histopathological changes of the skin tissues were observed.

RESULTS

All the tested drugs were capable of promoting new hair growth in the dorsal skin lesions of the mice. Among these drugs, Henna produced the most pronounced therapeutic effect and resulted in the highest dorsal hair density and a color change of the dorsal skin into gray; Lawsonia inermis L. showed the poorest therapeutic effect and resulted in the lowest dorsal hair density. The total number of follicles and the number of terminal hair follicles in a given field were significantly higher in all the drug treatment groups than in the model group (P < 0.05). In Impatiens balsamina group and Henna group, the contents of testosterone and dihydrotestosterone in the skin were significantly lower than those in the model group (P < 0.05). No significant difference was found in serum testosterone and dihydrotestosterone levels or skin 5α reductase type Ⅱ level between the drug treatment groups and the model group.

CONCLUSIONS

Impatiens balsamina, Lawsonia inermis L., and Henna all have therapeutic effects on androgenetic alopecia in C57BL/6 mice. The therapeutic effect of Impatiens balsamina and Henna is possibly achieved by reducing androgen content in local skin tissue.

Species- and developmental stage-specific effects of allelopathy and competition of invasive Impatiens glandulifera on co-occurring plants

Background

Impacts of invasive species on native communities are often difficult to assess, because they depend on a range of factors, such as species identity and traits. Such context-dependencies are poorly understood yet, but knowledge is required to predict the impact of invasions.

Materials and methods

We assessed species- and developmental stage-specificity of competitive and allelopathic effects of the invasive plant Impatiens glandulifera on different developmental stages of four native plant species. While some studies have shown a reduction in plant growth caused by I. glandulifera, the magnitude of its impact is ambiguous. For our study we used seedlings and juveniles of I. glandulifera and the native target species Geum urbanum, Filipendula ulmaria, Urtica dioica, and Salix fragilis (seedlings only of the latter), which often co-occur with I. glandulifera in different habitats. Plants were grown in competition with I. glandulifera or treated with I. glandulifera leaf material, or 2-metoxy-1,4-naphtoquinone (2-MNQ), its supposedly main allelochemical.

Results and conclusions

Overall I. glandulifera had a negative effect on the growth of all target species depending on the species and on the plant’s developmental stage. F. ulmaria was the least affected and U. dioica the most, and seedlings were less affected than juveniles. The species-specific response to I. glandulifera may lead to an altered community composition in the field, while growth reduction of seedlings and juveniles should give I. glandulifera an advantage in cases where plant recruitment is crucial. 2-MNQ led to minor reductions in plant growth, suggesting that it may not be the only allelopathic substance of I. glandulifera. Surprisingly, I. glandulifera was not fully tolerant to 2-MNQ. This autotoxicity could contribute to I. glandulifera population dynamics. We conclude that I. glandulifera reduces the growth of native vegetation and alters early successional stages without fully hindering it.

Antinociceptive activity of methanol extract of flowers of Impatiens balsamina

ETHNOPHARMACOLOGICAL RELEVANCE

Impatiens balsamina Linn. (Balsaminaceae), an annual herb locally called "Dopati", is cultivated as an ornamental garden plant in Bangladesh. Flowers of the plant are used in folk medicine to treat lumbago, neuralgia, burns and scalds.

AIM OF THE STUDY

This study evaluated the antinociceptive effect of the methanol extract of I. balsamina flowers (MIB).

MATERIALS AND METHODS

The extract was evaluated for antinociceptive activity using chemical- and heat-induced pain models such as acetic acid-induced writhing, hot plate, tail immersion and formalin test. To verify the possible involvement of opioid receptor in the central antinociceptive effect of MIB, naloxone was used to antagonize the effect. The effect of MIB on central nervous system (CNS) was also studied using hole cross and open field tests.

RESULTS

MIB demonstrated strong and dose-dependent antinociceptive activity in all the chemical- and heat-induced mice models (p<0.05). These findings imply the involvement of both peripheral and central antinociceptive mechanisms. The use of naloxone confirmed the association of opioid receptors in the central antinociceptive effect. MIB also showed significant central nervous system depressant effect (p<0.05).

CONCLUSION

This study reported the peripheral and central antinociceptive activity of the flowers of I. balsamina and rationalized the traditional use of the flower in the treatment of different painful conditions.

Within-plant distribution of twospotted spider mites (Acari: Tetranychidae) on impatiens: development of a presence-absence sampling plan

The twospotted spider mite, Tetranychus urticae Koch, is an important pest of impatiens, a floricultural crop of increasing economic importance in the United States. The large amount of foliage on individual impatiens plants, the small size of mites, and their ability to quickly build high populations make a reliable sampling method essential when developing a pest management program. In our study, we were particularly interested in using spider mite counts as a basis for releasing biological control agents. The within-plant distribution of mites was established in greenhouse experiments and these data were used to identify the sampling unit. Leaves were divided into three zones according to location on the plant: inner, intermediate, and other. On average, 40, 33, and 27% of the leaves belonged to the inner, intermediate, and other leaf zones, respectively. However, because 60% of the mites consistently were found on the intermediate leaves, intermediate leaves were chosen as the sampling unit. These results lead to the development of a presence-absence sampling method for T. urticae by using Taylor coefficients generic for this pest. The accuracy of this method was verified against an independent data set. By determining numerical or binomial sample sizes for consistently estimating twospotted spider mite populations, growers will now be able to determine the number of predatory mites that should be released to control twospotted spider mites on impatiens.

Effects on blood pressure decrease in response to PAF of Impatiens textori MIQ

A 35% EtOH extract of flowers of Impatiens textori MIQ. showed an inhibitory effect on blood pressure decrease in response to platelet activating factor (PAF) measured with a blood pressure monitoring system. Bioassay-guided fractionation of the 35% EtOH extract (IT) led to isolation of the flavones apigenin (1) and luteolin (3), which significantly inhibited blood pressure decrease in response to PAF. Their compounds and apigenin 7-glucoside (2), chrysoeriol (4), quercetin (5), quercetin 3-glucoside (6), kaempferol (7), kaempferol 3-glucoside (8) and kaempferol 3-rhamnosyldiglucoside (9) were also isolated from the flowers of I. textori for the first time. This study revealed that the flowers of I. textori might be a possible anti-allergy agent.

Dodder hyphae invade the host: a structural and immunocytochemical characterization

Dodder (Cuscuta pentagona) hyphae are unique amongst the parasitic weeds for their ability to apparently grow through the walls of the host plant. Closer examination reveals, however, that the hyphae do not grow through the host but rather induce the host to form a new cell wall (or extend the existing wall) to coat the growing hypha. This chimeric wall composed of walls from two species is even traversed by plasmodesmata that connect the two cytoplasms. Compositionally, the chimeric wall is quite different from the walls of either the host or in other cells of the dodder plant, on the basis of immunocytochemical labeling. The most striking differences were in the pectins, with much stronger labeling present in the chimeric wall than in either the host or other dodder walls. Interestingly, labeling with monoclonal antibodies specific to arabinan side chains of rhamnogalacturonan I pectin fraction was highly enriched in the chimeric wall, but antibodies to galactan side chains revealed no labeling. Arabinogalactan protein antibodies labeled the plasma membrane and vesicles at the tips of the hyphae and the complementary host wall, although the JIM8-reactive epitope, associated with very lipophilic arabinogalactan proteins, was found only in dodder cells and not the host. Callose was found in the plasmodesmata and along the forming hyphal wall but was found at low levels in the host wall. The low level of host wall labeling with anticallose indicates that a typical woundlike response was not induced by the dodder. When dodder infects leaf lamina, which have more abundant intercellular spaces than petioles or shoots, the hyphae grew both intra- and extracellularly. In the latter condition, a host wall did not ensheath the parasite and there was clear degradation of the host middle lamellae by the growing hyphae, allowing the dodder to pass between cells. These data indicate that the chimeric walls formed from the growth of the host cell wall in concert with the developing hyphae are unique in composition and structure and represent an induction of a wall type in the host that is not noted in surrounding walls.

Isolation of an antimicrobial compound from Impatiens balsamina L. using bioassay-guided fractionation

By using brine shrimp (Artemia salina) lethality test-guided fractionation, a single bioactive compound (LC(50)=26 ppm) was isolated from the 95% ethanol extract of the dried aerial parts of Impatiens balsamina L. and subsequently identified as 2-methoxy-1,4-naphthoquinone (MNQ). The structure of MNQ was confirmed by UV, FT-IR, MS, and 1-and 2-D NMR spectroscopy. The antimicrobial activity of MNQ was evaluated using 12 bacterial and eight fungal strains. Five gram-positive and two gram-negative bacteria as well as all eight fungi (including multi-drug resistant strains) tested were highly sensitive to MNQ. A tea prepared according to traditional methods was found to contain sufficient MNQ to account for its antimicrobial properties.

Interaction of Gibberellic Acid and Indoleacetic Acid in Impatiens

Gibberellic acid promotes doubling, early flowering, and fruiting directly in Impatiens. It also lengthens the stem, probably through a neutralization of auxin inhibitors. Such a mechanism would leave the growth-promoting auxins unchecked to produce the increased elongation characteristic of gibberellin application. It seems that application of additional auxin produces a rapid build-up of the auxin inhibitor(s) in the plant.