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The amount of atmospheric nitrogen-containing aerosols has increased dramatically due to the globally rising levels of nitrogen from fertilization and atmospheric deposition. Although the balance of carbon and nitrogen in plants is a crucial component of physiological and biochemical indexes and plays a key role in adaptive regulation, our understanding of how nitrogen-containing aerosols affect this remains limited; in particular, regarding the associated mechanisms. Using a fumigation particle generator, we generated ammonium nitrate solution (in four concentrations of 0, 15, 30, 60 kg N hm-2 year-1) into droplets, in 90% of which the diameters were less than 2.5 µm, in the range of 0.35-4 µm, and fumigated Iris germanica L. and Portulaca grandiflora Hook. for 30 days in April and August. We found that the weight percentage of nitrogen in the upper epidermis, mesophyll tissue, and bulk of leaves decreased significantly with the N addition rate, which caused a decrease of carbon:nitrogen ratio, due to the enhanced net photosynthetic rate. Compared with Portulaca grandiflora Hook., Iris germanica L. responded more significantly to the disturbance of N addition, resulting in a decrease in the weight percentage of nitrogen in the roots, due to a lower nitrogen use efficiency. In addition, the superoxide dismutase activity of the two plants was inhibited with a higher concentration of nitrogen sol; a reduction of superoxide dismutase activity in plants means that the resistance of plants to various environmental stresses is reduced, and this decrease in superoxide dismutase activity may be related to ROS signaling. The results suggest that inorganic nitrogen-containing aerosols caused excessive stress to plants, especially for Iris germanica L.

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Drought greatly affects the growth and development of garden plants and affects their ornamental value. WRKY transcription factors make up one of the largest transcription factor families in plants and they play an important role in the plant response to drought stress. However, the function of the WRKY gene in response to drought stress in Iris germanica, which is commonly used in landscaping, has not been studied. In this study, we isolated two WRKY transcription factor genes from Iris germanica, IgWRKY50 and IgWRKY32, which belong to Group II and Group III of the WRKY family, respectively. IgWRKY50 and IgWRKY32 could be induced by PEG-6000, high temperature and ABA in Iris germanica. IgWRKY50 and IgWRKY32 could quickly respond to drought and they peaked at 3 h after PEG-6000 treatment (19.93- and 23.32-fold). The fusion proteins IgWRKY50-GFP and IgWRKY32-GFP were located in the nucleus of mesophyll protoplasts of Arabidopsis. The overexpression of the IgWRKY50 and IgWRKY32 genes improved the osmotic tolerance of transgenic Arabidopsis, mainly exhibited by the transgenic plants having a higher germination rate and a longer total root length on 1/2 MS medium containing mannitol. Under PEG-6000 stress, the transgenic plants had higher stomatal closure than the wild type (WT). Under natural drought stress, the water loss rate of the isolated leaves of transgenic Arabidopsis was lower than that of WT, the contents of proline (Pro) and soluble protein (SP) and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the transgenic plants were higher, but the content of malondialdehyde (MDA) was lower. Furthermore, the expression of several stress-related genes (RD29A, DREB2A, PP2CA, and ABA2) was significantly increased in IgWRKY50- and IgWRKY32- overexpressing transgenic Arabidposis plants after drought treatment. These results suggest that IgWRKY50 and IgWRKY32, as two positive regulators, enhance the drought resistance of transgenic Arabidopsis by mediating the ABA signal transduction pathway. IgWRKY50 and IgWRKY32 can be used as candidate genes for molecular breeding of drought resistance in Iris.

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The family of B-box (BBX) transcription factors contains one or two B-BOX domains and sometimes also features a highly conserved CCT domain, which plays important roles in plant growth, development and stress response. Nevertheless, no systematic study of the BBX gene family in Iris germanica L. has been undertaken. In this study, a set of six BBX TF family genes from I. germanica was identified based on transcriptomic sequences, and clustered into three clades according to phylogenetic analysis. A transient expression analysis revealed that all six BBX proteins were localized in the nucleus. A yeast one-hybrid assay demonstrated that IgBBX3 has transactivational activity, while IgBBX1, IgBBX2, IgBBX4, and IgBBX5 have no transcriptional activation ability. The transcript abundance of IgBBXs in different tissues was divided into two major groups. The expression of IgBBX1, IgBBX2, IgBBX3 and IgBBX5 was higher in leaves, whereas IgBBX4 and IgBBX6 was higher in roots. The stress response patterns of six IgBBX were detected under phytohormone treatments and abiotic stresses. The results of this study lay the basis for further research on the functions of BBX gene family members in plant hormone and stress responses, which will promote their application in I. germanica breeding.

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BACKGROUND AND PURPOSE: Previous studies have shown the antioxidant, anti-inflammatory, immunomodulatory, and hypolipidemic activities of Iris germanica. The aim of the present study was to evaluate the protective effects of hydroalcoholic extract of Iris germanica rhizomes on streptozotocin-induced diabetic rats. EXPERIMENTAL APPROACH: Twenty-four male Wistar rats were randomly assigned into four groups including a normal control group, diabetic control group, diabetic groups treated for 4 weeks with 100 and 200 mg/kg/day of the Iris germanica extract (IGE). FINDINGS/RESULTS: Induction of diabetes significantly decreased the body weight gain and considerably increased the serum levels of glucose, triglyceride, blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Diabetes also diminished the antioxidant capacity of the liver (decrease of thiol groups) and significantly degenerated pancreatic islands. The IGE at both doses of 100 and 200 mg/kg significantly reduced the levels of glucose, triglyceride, AST, ALT, and ALP. Moreover, IGE increased the total antioxidant capacity of the liver and ameliorated pancreatic island morphology. The extract had no significant effect on body weight and BUN level. CONCLUSION AND IMPLICATION: These findings suggest that Iris germanica rhizomes inhibits the progression of hyperglycemia and hypertriglyceridemia and has protective effects against diabetes-induced injury of the liver and pancreas. Therefore, this plant has the potential to be used as a natural product for controlling diabetes.

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OBJECTIVES: Iris germanica L. is a medicinal plant, which has a long history of uses, mainly in medieval Persia and many places worldwide for the management of a wide variety of diseases. In this study, we aimed to review ethnopharmacological applications in addition to phytochemical and pharmacological properties of I. germanica. KEY FINDINGS: Ethnomedical uses of I. germanica have been reported from many countries such as China, Pakistan, India, Iran and Turkey. The medicinal part of I. germanica is the rhizome and the roots. Based on phytochemical investigations, different bioactive compounds, including flavonoids, triterpenes, sterols, phenolics, ceramides and benzoquinones, have been identified in its medicinal parts. Current pharmacological studies represent that the plant possesses several biological and therapeutic effects, including neuroprotective, hypoglycaemic, hypolipidaemic, antimicrobial, antioxidant, antiproliferative, anti-inflammatory, antiplasmodial, antifungal, immunomodulatory, cytotoxic and antimutagenic effects. SUMMARY: Although the majority of preclinical studies reported various pharmacological activities of this plant, however, sufficient clinical trials are not currently available. Therefore, to draw a definitive conclusion about the efficacy and therapeutic activities of I. germanica and its bioactive compounds, further clinical and experimental studies are required. Moreover, it is necessary to focus on the pharmacokinetic and safety studies on the extracts of I. germanica.

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BACKGROUND: The reblooming bearded iris (Iris germanica) can bloom twice a year, in spring and autumn. The extended ornamental period makes it more popular and brings additional commercial values. However, little is known about the reblooming mechanisms, making the breeding programs time-consuming and labor-wasting. Therefore, a comparative transcriptome profiling was conducted on once-bloomers and rebloomers from the same F1 generation on six development stages, and the candidate genes associated with reblooming were identified. RESULTS: A total of 100,391 unigenes were generated, the mean length being 785 bp. In the three comparisons (the floral initiation stage of spring flowering in once-bloomers (OB-T1) vs the floral initiation stage of spring flowering in rebloomers (RB-T1); RB-T1 vs the floral initiation stage of autumn flowering in rebloomers (RB-T5); OB-T1 vs RB-T5), a total of 690, 3515 and 2941 differentially expressed genes (DEGs) were annotated against the public databases, respectively. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis focused on the photoperiod response, the temperature insensitivity and the growth speed, to remove the redundant DEGs and figure out the candidate key genes. As a result, the following four genes, PHYTOCHROME A (PHYA), GIGANTEA (GI), SHORT VEGETATIVE PERIOD (SVP) and AUXIN RESPONSE FACTOR (ARF), were considered to be involved in the second floral initiation of the rebloomers. CONCLUSION: This research provides valuable information for the discovery of the reblooming-related genes. The insights into the molecular mechanisms of reblooming may accelerate the breeding of bearded iris and other perennials.

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Iris is one of the most popular and best-selling ornamental plants around the globe. Fusarium root rot disease, Fusarium oxysporum f.sp. gladioli (FOG) is one of the most serious disease of Iridaceae and Iris plants. In this study, three resistant and three susceptible Iris genotypes were inoculated with FOG isolates to evaluate expression of related genes promoting defense to disease at intervals times at two, four and six weeks post inoculation. Total RNA was extracted using an AccuZol™ reagent, and the first-strand Cdna was synthesized accordingly. Expression level of WRKY transcription factors (WRKY), lectin receptor kinase (LecRK), pathogenesis-related protein (PR3), lipoxygenase (LOX1) and ribosome-inactivating proteins (RIP) genes was investigated using quantitative polymerase chain reaction (qPCR). The transcriptional level of five defense-related genes were up-regulated in FOG-infected samples. The genes expression in resistant Iris genotypes NIOP3, NIOP15 and NIOP16 was much higher than susceptible NIOP1, NIOP12 and NIOP20 genotypes. The highest level of expression was observed in all the genes and genotypes at 6 weeks post inoculation. The phenotypic symptoms of genotypes and changes in the expression of genes confirmed resistance in Iris genotypes NIOP3, NIOP15 and NIOP16 in comparison to susceptible genotypes NIOP1, NIOP12 and NIOP20, and un-inoculated control Iris plants. Identifying disease-resistant genotypes can contribute to the development of new ornamental cultivars that can be deployed to ensure high quality and lasting Iris plants.

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BACKGROUND: Alzheimer's disease (AD) is the most common cause of dementia that is an irretrievable chronic neurodegenerative disease. In the current study, we have examined the therapeutic effects of Iris germanica extract on Amyloid ß (Aß) induced memory impairment. MATERIALS AND METHODS: Wistar rats were divided into five groups of 8 per each. Groups were as followed: control group which were normal rats without induction of AD, Aß group which received Aß (50 ng/side), iris 100 group which received Aß + Iris (100 mg/kg), iris 200 group which received Aß + Iris (200 mg/kg), and iris 400 group which received Aß + Iris (400 mg/kg). AD was established by intrahippocampal injection of 50 ng/µl/side Aß1-42. The day after surgery, animals in treatment groups received different doses of the aqueous extract of Iris by gavage for 30 days. Morris water maze test (MWM) was performed to assess the effects of I. germanica on learning and memory of rats with Aß induced AD. RESULTS: Data from MWM tests, including escape latency and traveled distance, demonstrated that I. germanica extract could markedly improve spatial memory in comparison to control. Moreover, the plant had a significantly better effect on the performance of AD rats in the probe test. CONCLUSION: I. germanica extract can successfully reverse spatial learning dysfunction in an experimental model of AD. Further neuro psyco-pharmacological studies are mandatory to reveal the mechanism of action of this natural remedy in the management of AD symptoms.

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ABSTRACT A new isoflavonoid glycoside, iridin A (9), along with eight known isoflavonoids: irilone 4'-methyl ether (1), irilone (2), irisolidone (3), irigenin S (4), irigenin (5), irilone 4'-O-β-D-glucopyranoside (6), iridin S (7), and iridin (8) were separated from Iris × germanica L., Iridaceae, rhizomes. The structural elucidation of these flavonoids was achieved with the aid of extensive spectroscopic techniques and comparing with the published data. They were estimated for their α-amylase and 1,1-diphenyl-2-picrylhydrazyl inhibitory capacities. Compounds 3, 5, and 9 showed α-amylase inhibitory activities with % inhibition 70.8, 67.5, and 70.5, respectively compared to acarbose (a reference α-amylase inhibitor). Moreover, 9 exhibited moderate antioxidant activity with IC50 8.91 µM.

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Iris species are well recognized as wealthy sources of isoflavonoids. In the present study, phytochemical investigation of the rhizomes of Iris germanica (Iridaceae) procure the isolation of two new isoflavonoids namely, 8-hydroxyirilone 5-methyl ether (2) and 8-hydroxyirilone (3), along with eight known isoflavonoids: irilone 4'-methyl ether (1), irilone (4), irisolidone (5), irigenin S (6), irigenin (7), irilone 4'-O-ß-d-glucopyranoside (8), iridin S (9), and iridin (10). The isolated flavonoids were structurally characterized with the assist of comprehensive spectroscopic analyses (UV, IR, 1D and 2D NMR, and HRMS) and comparing with the published data. They were estimated for their antioxidant and antidaibetic capacities using DPPH and α-amylase inhibition assays, respectively. Compounds 2, 3, and 4 exhibited prominent antioxidant activities with IC50 values of 12.92, 9.23, and 10.46µM, respectively compared to propyl gallate (IC50 7.11µM). Moreover, 2-5 possessed highest α-amylase inhibitory activity with % inhibition 66.1, 78.3, 67.3, and 70.1, respectively in comparison to acarbose (reference α-amylase inhibitor). Additionally, their structure-activity relationship has been discussed.

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This study was designed to investigate antioxidant and anticholinesterase potential of Iris germanica var; florentina. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential of plant samples were investigated by Ellman's assay. Antioxidant activity was performed using DPPH, H2O2 and ABTS free radical scavenging assays. Total phenolics and flavonoids contents were expressed in mg GAE/g dry weight and mg RTE/g, respectively. In AChE inhibition assay, Ig.Fl, Ig.Sp and Ig.Cf fractions exhibited highest activity with IC50 values of < 0.1, 5.64 and 19 µg/mL, respectively. In BChE inhibitory assay, Ig.Fl, Ig.Sp, Ig.Cf and Ig.Cr were most active with IC50 of < 0.1, < 0.1, 31 and 78 µg/mL, respectively. In DPPH assay, Ig.Fl and Ig.Cf exhibited highest inhibition of free radicals, 80.52% (IC50 = 9 µg/mL) and 78.30% (IC50 = 8 µg/mL), respectively. In ABTS assay Ig.Cr, Ig.Cf, Ig.Fl and Ig.Sp exhibited IC50 values of < 0.1, 2, 2 and 3 µg/mL, respectively.

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