Search Results (14)

A previous study of Narcissus species on the Maltese Islands had suggested the existence of a natural hybridogenous species. A fresh study on Narcissus in Malta was conducted in 2021 and 2023 with the primary aim of studying the previously reported populations of intermediate forms and to update the taxonomy of Narcissus in Malta. Four main taxa of native species were identified: N. deficiens, two distinct morphotypes of N. tazetta, and a new hybrid species. The species identified as N. deficiens replaces records of N. serotinus and N. obsoletus. One of the two morphotypes (“autumn-flowering”) is now combined as subsp. aequilimbus (previously described from Maltese material as Hermione aequilimba) and the other one (“spring-flowering”) corresponds to subsp. tazetta. The new hybrid is derived from N. deficiens and N. tazetta and is named N × briffae. This hybrid was previously incorrectly reported as N. elegans. Detailed morphometric analysis and ecological data justify these new taxonomic appraisals. A dichotomous identification key for eight Narcissus taxa (including non-native ones) is provided to facilitate the identification of the occurring and doubtful species recorded on the Maltese Islands. Full article

Essential oils are natural plant products that are very interesting, as they are important sources of biologically active compounds. They comprise eco-friendly alternatives to mosquito vector management, particularly essential oil nanoemulsion. Therefore, the aim of this study is to evaluate the effectiveness of 16 selected essential oils (1500 ppm) in controlling mosquitoes by investigating their larvicidal effects against the larvae and adults of the West Nile virus vector Culex pipiens L. (Diptera: Culicidae); the best oils were turned into nanoemulsions and evaluated under laboratory and field conditions. The results show that honeysuckle (Lonicera caprifolium) and patchouli (Pogostemon cablin) essential oils were more effective in killing larvae than the other oils (100% mortality) at 24 h post-treatment. The nanoemulsions of honeysuckle (LC₅₀ = 88.30 ppm) and patchouli (LC₅₀ = 93.05 ppm) showed significantly higher larvicidal activity compared with bulk honeysuckle (LC₅₀ = 247.72 ppm) and patchouli (LC₅₀ = 276.29 ppm) oils. L. caprifolium and P. cablin (100% mortality), followed by Narcissus tazetta (97.78%), Rosmarinus officinalis (95.56%), and Lavandula angustifolia (95.55%), were highly effective oils in killing female mosquitoes, and their relative efficacy at LT₅₀ was 5.5, 5.3, 5.8, 4.1, and 3.2 times greater, respectively, than Aloe vera. The results of the field study show that the honeysuckle and patchouli oils and their nanoemulsions reduced densities to 89.4, 86.5, 98.6, and 97.0% at 24 h post-treatment, respectively, with persistence for eight days post-treatment in pools. Nano-honeysuckle (100% mortality) was more effective than honeysuckle oils (98.0%). Our results show that honeysuckle and patchouli oils exhibited promising larvicidal and adulticidal activity of C. pipiens. Full article

The gene encoding 1-hydroxy-2-methyl-2-(E)-butenyl-4-pyrophosphate reductase, a key enzyme at the end of the methylerythritol 4-phosphate pathway (MEP), was cloned from the petals of Narcissus tazetta var. Chinensis ‘Jinzhanyintai’ and named NtHDR (accession number OQ739816). NtHDR exhibits a full-length coding sequence spanning 1380 base pairs, encoding a total of 460 amino acids. Through phylogenetic-tree analysis, it has been determined that NtHDR shared the closest evolutionary relationship with monocotyledons, specifically Asparagus officinalis and Zingiber officinale. Utilizing quantitative real-time PCR analysis, it was observed that NtHDR exhibited significant expression in both petals and corona, with expression levels varying throughout the flowering process of Narcissus. Specifically, in petals, NtHDR expression demonstrated a pattern of initial increase followed by subsequent decrease, while in corona, it consistently increased. Subsequent subcellular-localization experiments indicated that NtHDR was localized within the chloroplasts. To investigate the functional impact of NtHDR, a stable transformation was performed, where NtHDR was introduced into Nicotiana benthamiana. The resulting transgenic N. benthamiana flowers were analyzed using solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS) to characterize their volatile components. The analysis revealed the presence of the monoterpene compound linalool, as well as the phenylpropanoids benzyl alcohol and phenylethanol, within the floral fragrance components of the transgenic N. benthamiana plants. However, these compounds were absent in the floral fragrance components of wild-type tobacco plants, thus highlighting the impact of NtHDR transformation on the floral scent profile. Full article

Plants of the genus Narcissus are well-known for their characteristic corona morphology, which structural origins have been a bone of contention among scholars. With “Jinzhanyintai” (JZ) and “Yulinglong” (YLL)—two major close-originated cultivars of Chinese narcissus (Narcissus tazetta L. var. chinensis Roem)—as materials, anatomic observation was made on floral organs during corona morphogenesis by dissection with hands under a stereomicroscope, paraffin section, scanning electron microscopy, and high-resolution X-ray tomography. It was uncovered that corona primordia of both cultivars appeared following the end of the differentiation of other floral organs, with differentiation sites located at the inner wall of the juncture of the base of tepals and the upper margin of the hypanthium. Affected by staminal filaments, the corona primordia of JZ experienced a three-stage differentiation process, namely blockage from the second whorl of stamens, blockage from the first whorl of stamens, and healing of corona primordia. However, the expanded spatial structure of the first whorl of petal-like stamens blocked the path of differentiation of YLL corona primordia, giving rise to slow differentiation of the corona primordia at the base of the first whorl of petal-like stamens and malformed differentiation of the corona primordia in the interval between the two whorls of petal-like stamens. Thus, a fragmented structure consisting of typical and fragmented coronas was formed. Furthermore, petal-like stamens of YLL in the lower part had a corona-like morphology. The spatio-temporal specificity of corona differentiation convincingly demonstrates that the corona is a structure independent of and different from the typical four whorls of floral organs, but also highly correlated with stamen. Full article

Chinese narcissus (Narcissus tazetta var. chinensis) was introduced to China 1300–1400 years ago, and has grown naturally in southeastern China. It is a popular Chinese traditional potted flower and a well-known flowering bulb cultivated worldwide with only two white-tepal triploid cultivars, ‘Jinzhan Yintai’ and ‘Yulinglong’. Recently, a mutant with yellow tepals was observed and promptly became popular. To clarify the key pigment for color difference and its molecular mechanism of accumulation, we conducted pigment metabolite analysis and comparative transcriptome analysis on ‘Jinzhan Yintai’ and the yellow-flowered mutant. The results showed that there was no significant difference in total flavonoid content between the mutant and ‘Jinzhan Yintai’, whereas the total carotenoid content of the mutant was more than 10-fold higher than that of ‘Jinzhan Yintai’. Based on the RNA-sequencing results, sixty-four unigenes, corresponding to 29 enzymes associated with the carotenoid biosynthesis pathway, were analyzed in detail. A comparative KEGG pathway enrichment analysis, in conjunction with quantitative real-time PCR data, revealed the opposite gene expression mode of the carotenoid biosynthesis pathway. Compared with ‘Jinzhan Yintai ’, PSY and PDS were up-regulated in the three mid-flowering stages of the mutant, whereas NCED genes were strongly down-regulated, which likely contributed to carotenoid accumulation in chromoplasts of the tepals in the mutant. Full article

Narcissus tazetta var. chinensis M.Roem. (Chinese Narcissus) is a traditional and famous flower in China, and its corona shows a transition from green to yellow with the opening of flowers, which is of great ornamental value. To investigate the molecular mechanism of the corona color-forming in the Chinese Narcissus, in this study, a MYB gene was screened from the transcriptome of the corona by bioinformatics analysis methods, named NtMYB9. The expression level of the NtMYB9 gene was significantly higher in the corona than in the tepal, filament, ovary and leaf, and reached the highest level at the fourth period of complete coloration of the corona. The full-length sequence of the NtMYB9 coding region was cloned using the corona cDNA as a template. Sequence analysis revealed that NtMYB9 protein contained R2 and R3 domains, phylogenetic tree analysis showed that the NtMYB9 protein was most closely related to flavonol activators. Subcellular localization showed that NtMYB9 was localized in the nucleus. The overexpression of NtMYB9 gene into tobacco leaves and the expression level of seven enzyme genes related to the flavonoid biosynthesis pathway were significantly up-regulated. The transient transformation of Petunia × hybrida (Petunia) and Phalaenopsis aphrodite (Phalaenopsis) significantly revealed that the NtMYB9 gene could turn flowers yellow. These results suggest that the NtMYB9 gene is involved in the positive regulation of flavonoid biosynthesis in the Chinese Narcissus and may promote the synthesis of flavonols. In conclusion, these findings provide a valuable resource for further studies on the regulatory mechanism of the flavonoid biosynthesis pathway, and they are also beneficial to the molecular breeding of Chinese Narcissus. Full article

A link between the scent and color of Narcissus tazetta flowers can be anticipated due to their biochemical origin, as well as their similar biological role. Despite the obvious aesthetic and ecological significance of these colorful and fragrant components of the flowers and the molecular profiles of their pigments, fragrant formation has addressed in some cases. However, the regulatory mechanism of the correlation of fragrant components and color patterns is less clear. We simultaneously used one way to address how floral color and fragrant formation in different tissues are generated during the development of an individual plant by transcriptome-based weighted gene co-expression network analysis (WGCNA). A spatiotemporal pattern variation of flavonols/carotenoids/chlorophyll pigmentation and benzenoid/phenylpropanoid/ monoterpene fragrant components between the tepal and corona in the flower tissues of Narcissus tazetta, was exhibited. Several candidate transcription factors: MYB12, MYB1, AP2-ERF, bZIP, NAC, MYB, C2C2, C2H2 and GRAS are shown to be associated with metabolite flux, the phenylpropanoid pathway to the production of flavonols/anthocyanin, as well as related to one branch of the phenylpropanoid pathway to the benzenoid/phenylpropanoid component in the tepal and the metabolite flux between the monoterpene and carotenoids biosynthesis pathway in coronas. It indicates that potential competition exists between floral pigment and floral fragrance during Narcissus tazetta individual plant development and evolutionary development. Full article

Alkaloids produced by the bulbs of the Amaryllidaceae are a source of pharmaceutical compounds. The main alkaloid, galantamine, is a reversible acetylcholinesterase inhibitor and allosteric nicotinic receptor modulator, which slows cognitive and functional decline in mild to moderate dementia due to Alzheimer’s disease. Having a complex stereochemistry, the organic synthesis of galantamine for pharmaceutical uses is highly challenging and not always economically viable, and it is therefore isolated from Amaryllidaceae bulbs. In the present study, galantamine was extracted and quantified in Narcissus bulbs from five cultivars (cvs.), Fortune, Carlton, Ice Follies, Galilee and Ziva, which were grown in Israel under various conditions. Results show that the cvs. Fortune, Carlton and Ice Follies bulbs contained 285 ± 47, 452 ± 73 and 69 ± 17 µg g⁻¹ galantamine, respectively, while the Galilee and Ziva bulbs contained relatively low concentrations of galantamine (1–20 µg g⁻¹). Irrigation levels and pruning conditions did not affect the galantamine contents. Additionally, the alkaloids profile of the five cvs. was analyzed and characterized using LC-MS/MS showing that galantamine-type alkaloids were mainly detected in the Fortune and Carlton bulbs, lycorine-type alkaloids were mainly detected at the Galilee and Ziva bulbs and vittatine-type alkaloids were mainly detected in the Ice Follies bulbs. The present research is the first to characterize the alkaloids profile in the Narcissus bulbs of Galilee and Ziva, indigenous cvs. grown in Israel. The antiviral and anticancer alkaloids lycorine and lycorinine were the main alkaloids detected in the bulbs of those cultivars. Full article

R2R3-MYB transcription factors play important roles in the regulation of plant flavonoid metabolites. In the current study, NtMYB3, a novel R2R3-MYB transcriptional factor isolated from Chinese narcissus (Narcissus tazetta L. var. chinensis), was functionally characterized. Phylogenetic analysis indicated that NtMYB3 belongs to the AtMYB4-like clade, which includes repressor MYBs involved in the regulation of flavonoid biosynthesis. Transient assays showed that NtMYB3 significantly reduced red pigmentation induced by the potato anthocyanin activator StMYB-AN1 in agro-infiltrated leaves of tobacco. Over-expression of NtMYB3 decreased the red color of transgenic tobacco flowers, with qRT-PCR analysis showing that NtMYB3 repressed the expression levels of genes involved in anthocyanin and flavonol biosynthesis. However, the proanthocyanin content in flowers of transgenic tobacco increased as compared to wild type. NtMYB3 showed expression in all examined narcissus tissues; the expression level in basal plates of the bulb was highest. A 968 bp promoter fragment of narcissus FLS (NtFLS) was cloned, and transient expression and dual luciferase assays showed NtMYB3 repressed the promoter activity. These results reveal that NtMYB3 is involved in the regulation of flavonoid biosynthesis in narcissus by repressing the biosynthesis of flavonols, and this leads to proanthocyanin accumulation in the basal plate of narcissus. Full article

Since the skin is the major protective barrier of the body, it is affected by intrinsic and extrinsic factors. Environmental influences such as ultraviolet (UV) irradiation, pollution or dry/cold air are involved in the generation of radical oxygen species (ROS) and impact skin aging and dermal health. Assessment of human skin gene expression and other biomarkers including epigenetic factors are used to evaluate the biological/molecular activities of key compounds in cosmetic formulas. The objective of this study was to quantify human gene expression when epidermal full-thickness skin equivalents were exposed to: (a) a mixture of betaine, pentylene glycol, Saccharomyces cerevisiae and Rhodiola rosea root extract (BlendE) for antioxidant, skin barrier function and oxidative stress (with hydrogen peroxide challenge); and (b) a mixture of Narcissus tazetta bulb extract and Schisandra chinensis fruit extract (BlendIP) for various biomarkers and microRNA analysis. For BlendE, several antioxidants, protective oxidative stress biomarkers and many skin barrier function parameters were significantly increased. When BlendE was evaluated, the negative impact of the hydrogen peroxide was significantly reduced for the matrix metalloproteinases (MMP 3 and MMP 12), the skin aging and oxidative stress biomarkers, namely FBN2, ANXA1 and HGF. When BlendIP was tested for cell proliferation and dermal structural components to enhance the integrity of the skin around the eyes: 8 growth factors, 7 signaling, 7 structural/barrier function and 7 oxidative stress biomarkers were significantly increased. Finally, when BlendIP was tested via real-time RT-PCR for microRNA expression: miR-146a, miR-22, miR155, miR16 and miR21 were all significantly increased over control levels. Therefore, human skin gene expression studies are important tools to assess active ingredient compounds such as plant extract blends to advance dermal hypotheses toward validating cosmetic formulations with botanical molecules. Full article

R2R3 MYB transcription factors play key functions in the regulation of secondary metabolites. In the present study, a R2R3 MYB transcriptional factor NtMYB2 was identified from Chinese narcissus (Narcissus tazetta L. var. Chinensis Roem) and functionally characterized. NtMYB2 belongs to subgroup 4 of the R2R3 MYB transcription factor family that are related to repressor MYBs involved in the regulation of anthocyanin and flavonoids. Transient expression confirmed that NtMYB2 strongly reduced the red pigmentation induced by MYB- anthocyanin activators in agro-infiltrated tobacco leaves. Ectopic expression of NtMYB2 in tobacco significantly reduced the pigmentation and altered the floral phenotypes in transgenic tobacco flowers. Gene expression analysis suggested that NtMYB2 repressed the transcript levels of structural genes involved in anthocyanin biosynthesis pathway, especially the UFGT gene. NtMYB2 gene is expressed in all examined narcissus tissues; the levels of transcription in petals and corona is higher than other tissues and the transcription level at the bud stage was highest. These results show that NtMYB2 is involved in the regulation of anthocyanin biosynthesis pathway and may act as a repressor by down regulating the transcripts of key enzyme genes in Chinese narcissus. Full article

Chinese narcissus (Narcissus tazetta var. chinensis) is one of the ten traditional flowers in China and a famous bulb flower in the world flower market. However, only white color tepals are formed in mature flowers of the cultivated varieties, which constrains their applicable occasions. Unfortunately, for lack of genome information of narcissus species, the explanation of tepal color formation of Chinese narcissus is still not clear. Concerning no genome information, the application of transcriptome profile to dissect biological phenomena in plants was reported to be effective. As known, pigments are metabolites of related metabolic pathways, which dominantly decide flower color. In this study, transcriptome profile and pigment metabolite analysis methods were used in the most widely cultivated Chinese narcissus “Jinzhanyintai” to discover the structure of pigment metabolic pathways and their contributions to white tepal color formation during flower development and pigmentation processes. By using comparative KEGG pathway enrichment analysis, three pathways related to flavonoid, carotenoid and chlorophyll pigment metabolism showed significant variations. The structure of flavonoids metabolic pathway was depicted, but, due to the lack of F3ʹ5ʹH gene; the decreased expression of C4H, CHS and ANS genes; and the high expression of FLS gene, the effect of this pathway to synthesize functional anthocyanins in tepals was weak. Similarly, the expression of DXS, MCT and PSY genes in carotenoids synthesis sub-pathway was decreased, while CCD1/CCD4 genes in carotenoids degradation sub-pathway was increased; therefore, the effect of carotenoids metabolic pathway to synthesize adequate color pigments in tepals is restricted. Interestingly, genes in chlorophyll synthesis sub-pathway displayed uniform down-regulated expression, while genes in heme formation and chlorophyll breakdown sub-pathways displayed up-regulated expression, which also indicates negative regulation of chlorophyll formation. Further, content change trends of various color metabolites detected by HPLC in tepals are consistent with the additive gene expression patterns in each pathway. Therefore, all three pathways exhibit negative control of color pigments synthesis in tepals, finally resulting in the formation of white tepals. Interestingly, the content of chlorophyll was more than 10-fold higher than flavonoids and carotenoids metabolites, which indicates that chlorophyll metabolic pathway may play the major role in deciding tepal color formation of Chinese narcissus. Full article

The volatile components in single-flowered and double-flowered Chinese narcissus were identified by headspace-solid phase microextraction (HS-SPME) coupled with GC and GC/MS. Changes in aroma during the vase-life (days 0, 1, 2, 3, 4, 5 and 6) of two samples were also studied. A total of 35 compounds were identified, of which all were present in single-flowered and 26 in double-flowered samples. The main aroma components were (E)-β-ocimene, and benzyl acetate. Single-flowered narcissus have a higher percentage of benzyl acetate, while double-flowered narcissus have a higher percentage of 1,8-cineole. In vase-life, the total volatile component content peaked on day 2 for single-flowered and day 3 for the double-flowered narcissus. For both single-flowered and double-flowered narcissus flowers, the total content of volatile components had decreased significantly by day 4. Full article

Antimicrobial activity and cytotoxicity of fifty one extracts of different parts of 14 plants were studied. Ethanol, methanol, aqueous, butanol, and n-hexane extracts were tested against three Gram negative, two Gram positive bacteria, and two fungi. Cytotoxicity and phytochemical screening were determined using MTT and TLC assays, respectively. Of the fifty one extracts, twenty two showed activities against different microorganisms with MICs ranging from 62.5 to 1000 µg/mL. The highest activity (100% inhibition) was for a butanol extract of Rosa damascena receptacles against Salmonella typhimurium and Bacillus cereus (MIC of 62.5 and 250 µg/mL) respectively. Butanol extract of Narcissus tazetta aerial parts and aqueous extract of Rosa damascena receptacles were both active against Candida albicans (MIC of 125 µg/mL). Methicillin-resistant Staphylococcus aureus was inhibited by butanol, aqueous extracts of Rosa damascena receptacles and butanol extract of Inula viscosa flowers (MIC of 500, 500, and 250 µg/mL) respectively. Rosa damascena receptacles and Verbascum sinaiticum flowers ethanol extract showed lowest cytoxicity against Vero cell line (IC₅₀ of 454.11and 367.11). Most toxic was the ethanol extract of Ononis hirta aerial parts (IC₅₀ 72.50 µg/mL). Flavonoids and terpenoids were present in all plants. Ononis hirta and Narcissus tazetta contained alkaloids. The results validate the use of these plants and report for the first time bioactivity of Rosa damascena receptacles and further justifies the use of such screening programs in the quest for new drugs. Full article