Chemical composition, antioxidant and antimicrobial activities of essential oil from the aerial parts of Chuquiraga arcuataHarling grown in the highlands of Ecuador / Composición química, actividades antioxidantes y antimicrobianas del aceite esencial de las partes aéreas de Chuquiraga arcuataHarling cultivado en las tierras altas del Ecuador

Thechemical composition, antioxidant and antimicrobial activities of the essential oil from aerial parts (leaves and flowers) of Chuquiraga arcuataHarling grown in the Ecuadorian Andes were studied. One hundred and twenty-six compounds were identified in the essential oil. Monoterpene hydrocarbons (45.8%) and oxygenated monoterpenes (44.1%) had the major percentages. The most abundant compounds were camphor (21.6%), myrcene (19.5%), and 1,8-cineole (13.4%). Antioxidant activity was examined using DPPH, ABTS,and FRAP assays. The essential oil had a moderate scavenging effect and reduction of ferric ion capacity through FRAP assay. Antimicrobial activity of the essential oil was observed against four pathogenic bacteria and a fungus. The essential oil exhibited activity against all microorganism strains under test, particularly against Candida albicansand Staphylococcus aureuswith MICs of 2.43-12.10 µg/mL.

Se estudió la composición química, actividades antioxidantes y antimicrobianas del aceite esencial procedente de las partes aérea (hojas y flores) de Chuquiraga arcuataHarling cultivadas en los Andes ecuatorianos. Se identificaron 126 compuestos en el aceite esencial. Los hidrocarburos monoterpénicos (45,8%) y los monoterpenos oxigenados (44,1%) tuvieron el mayor porcentaje. Los compuestos más abundantes fueron alcanfor (21,6%), mirceno (19,5%) y 1,8-cineol (13,4%). La actividadantioxidante se examinó mediante ensayos DPPH, ABTS y FRAP. El aceite esencial tuvo un efecto eliminador moderado y una reducción de la capacidad de iones férricos mediante el ensayo FRAP. Se observó actividad antimicrobiana del aceite esencial contra cuatro bacterias y un hongo patógenos. El aceite esencial mostró actividad contra todas las cepas de microorganismos bajo prueba, particularmente contra Candida albicansy Staphylococcus aureuscon CMI de 2,43-12,10 µg/mL.

Potential role of Citrus bergamia flower essential oil against oral pathogens.

BACKGROUND: Oral bacterial infections are difficult to treat due to emergence of resistance against antibiotic therapy. Essential oils are considered emerging alternate therapy against bacterial infections and biofilms. We investigated Citrus bergemia flower essential oil against oral pathogens. METHODS: The essential oil was analsyed using Gas Chromatography(GC-MS), in silico investigations, antioxidant, antimicrobial, antibiofilm and antiquorum sensing assays. RESULTS: Gas Chromatography analysis confirmed presence of 17 compounds including 1,6-Octadien-3-ol,3,7-dimethyl, 48.17%), l-limonene (22.03%) and p-menth-1-ol, 8-ol (7.31%) as major components. In silico analysis showed compliance of all tested major components with Lipinski's rule, Bioavailability and antimicrobial activity using PASS (prediction of activity spectrum of substances). Molecular docking with transcriptional regulators 3QP5, 5OE3, 4B2O and 3Q3D revealed strong interaction of all tested compounds except 1,6-Octadien-3-ol,3,7-dimethyl. All tested compounds presented significant inhibition of DPPH (2,2-diphenyl-1-picrylhydrazyl) (IC50 0.65 mg/mL), H2O2 (hydrogen peroxide) (63.5%) and high FRAP (ferrous reducing antioxidant power) value (239.01 µg). In antimicrobial screening a significant activity (MIC 0.125 mg/mL) against Bacillus paramycoides and Bacillus chungangensis was observed. Likewise a strong antibiofilm (52.1 - 69.5%) and anti-QS (quorum sensing) (4-16 mm) activity was recorded in a dose dependent manner. CONCLUSION: It was therefore concluded that C. bergemia essential oil posess strong antioxidant, antimicrobial and antibiofilm activities against tested oral pathogens.

Extraction and characterization of fiber from the flower stalk of Sansevieria cylindrica.

A number of natural fibers are being proposed for use in composite materials, especially those extracted from local plants, especially those able to grow spontaneously as they are cost-efficient and have unexplored potential. Sansevieria cylindrica, within the Asparagaceae (previously Agavacae) family, has recently been considered for application in polymer and rubber matrix composites. However, its characterization and even the sorting out of technical fiber from the stem remains scarce, with little available data, as is often the case when the fabrication of textiles is not involved. In this study, Sansevieria cylindrica fibers were separated down to the dimensions of a filament at an 8-15 micron diameter from the stem of the plant, then characterized physically and chemically, using Fourier transform infrared spectroscopy (FTIR), morphologically by scanning electron microscopy (SEM), as well as their thermal degradation, by thermogravimetric analysis (TGA). Their crystallinity surface roughness was measured by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The results indicate over 70% cellulose fibers content with a very high crystallinity (92%) and small crystallite size (1.45 nm), which suggests a low water absorption, with thermal degradation peaking at 294°C. Despite this, due to the significant porosity of the cellular structure, the density of 1.06 g cm-3 is quite low for a mainly cellulose fiber. Roughness measurements indicate that the porosities and foamy structure result in a highly negative skewness (-3.953), in the presence of deep valleys, which may contribute to an effective relation with a covering resin.

Chinese cherry CpMYB44-CpSPDS2 module regulates spermidine content and florescence in tobacco.

The flower bud differentiation plays a crucial role in cherry yield and quality. In a preliminary study, we revealed the promotion of spermidine (Spd) in bud differentiation and quality. However, the molecular mechanism underlying Spd regulating cherry bud differentiation remains unclear. To address this research gap, we cloned CpSPDS2, a gene that encodes Spd synthase and is highly expressed in whole flowers and pistils of the Chinese cherry (cv. 'Manaohong'). Furthermore, an overexpression vector with this gene was constructed to transform tobacco plants. The findings demonstrated that transgenic lines exhibited higher Spd content, an earlier flowering time by 6 d, and more lateral buds and flowers than wild-type lines. Additionally, yeast one-hybrid assays and two-luciferase experiments confirmed that the R2R3-MYB transcription factor (CpMYB44) directly binds to and activates the CpSPDS2 promoter transcription. It is indicated that CpMYB44 promotes Spd accumulation via regulating CpSPDS2 expression, thus accelerating the flower growth. This research provides a basis for resolving the molecular mechanism of CpSPDS2 involved in cherry bud differentiation.

Analysis of pea mutants reveals the conserved role of FRUITFULL controlling the end of flowering and its potential to boost yield.

Monocarpic plants have a single reproductive phase in their life. Therefore, flower and fruit production are restricted to the length of this period. This reproductive strategy involves the regulation of flowering cessation by a coordinated arrest of the growth of the inflorescence meristems, optimizing resource allocation to ensure seed filling. Flowering cessation appears to be a regulated phenomenon in all monocarpic plants. Early studies in several species identified seed production as a major factor triggering inflorescence proliferative arrest. Recently, genetic factors controlling inflorescence arrest, in parallel to the putative signals elicited by seed production, have started to be uncovered in Arabidopsis, with the MADS-box gene FRUITFULL (FUL) playing a central role in the process. However, whether the genetic network regulating arrest is also at play in other species is completely unknown. Here, we show that this role of FUL is not restricted to Arabidopsis but is conserved in another monocarpic species with a different inflorescence structure, field pea, strongly suggesting that the network controlling the end of flowering is common to other plants. Moreover, field trials with lines carrying mutations in pea FUL genes show that they could be used to boost crop yield.

Transcriptomic and targeted metabolomic analyses provide insights into the flavonoids biosynthesis in the flowers of Lonicera macranthoides.

BACKGROUND: Flavonoids are one of the bioactive ingredients of Lonicera macranthoides (L. macranthoides), however, their biosynthesis in the flower is still unclear. In this study, combined transcriptomic and targeted metabolomic analyses were performed to clarify the flavonoids biosynthesis during flowering of L. macranthoides. RESULTS: In the three sample groups, GB_vs_WB, GB_vs_WF and GB_vs_GF, there were 25, 22 and 18 differentially expressed genes (DEGs) in flavonoids biosynthetic pathway respectively. A total of 339 flavonoids were detected and quantified at four developmental stages of flower in L. macranthoides. In the three sample groups, 113, 155 and 163 differentially accumulated flavonoids (DAFs) were detected respectively. Among the DAFs, most apigenin derivatives in flavones and most kaempferol derivatives in flavonols were up-regulated. Correlation analysis between DEGs and DAFs showed that the down-regulated expressions of the CHS, DFR, C4H, F3'H, CCoAOMT_32 and the up-regulated expressions of the two HCTs resulted in down-regulated levels of dihydroquercetin, epigallocatechin and up-regulated level of kaempferol-3-O-(6''-O-acetyl)-glucoside, cosmosiin and apigenin-4'-O-glucoside. The down-regulated expressions of F3H and FLS decreased the contents of 7 metabolites, including naringenin chalcone, proanthocyanidin B2, B3, B4, C1, limocitrin-3,7-di-O-glucoside and limocitrin-3-O-sophoroside. CONCLUSION: The findings are helpful for genetic improvement of varieties in L.macranthoides.

[Morphological study of sexual reproductive disorders in Ligusticum chuanxiong].

Chuanxiong Rhizoma is a well-known Sichuan-specific herbal medicine. Its original plant, Ligusticum chuanxiong, has been cultivated asexually for a long time. L. chuanxiong has sexual reproductive disorders, which restricts its germplasm innovation. However, there is little research on the reproductive system of L. chuanxiong. This study is based on a comparative anatomical research approach, using morphological dissection, paraffin sectioning, staining and compression, and combined with scanning electron microscopy technology, to observe and compare the flowers, fruits, and seeds at various stages of reproductive growth of L. chuanxiong and its wild relative L. sinense. The results showed that the meiosis of pollen mother cells is abnormal in L. chuanxiong anthers, and the size and number of microspores are uneven and inconsistent in the tetrad stage. tapetum cells are not completely degenerated during anther development. During the pollen ripening stage, there are fine cracks in the anther wall, while most anthers could not release pollen normally. The surface of mature pollen grains is concave and partially deformed, and the pollens are all inactive and cannot germinate in vitro. The starch, polysaccharides, and lipids in the pollen were insufficient. The filaments of L. chuanxiong are short at the flowering stage and recurved downward. Double-hanging fruits were observed in the fruiting stage, being wrinkled; with shriveled seeds. Compared with L. sinense at the same stage, the anthers of L. sinense developed normally, and the pollen grains are vigorous and can germinate in vitro. The double-hanging fruits of L. sinense are full and normal; at the flowering period, the filaments are long and erect, significantly higher than the stigma. Mature blastocysts are visible in the ovary of both L. chuanxiong and L. sinense, and there is no significant difference in stigmas. The conclusion is that during the development of L. chuanxiong stamens, the meiosis of pollen mother cells is abnormal, and tetrad, tapetum, filament and other pollen structures develop abnormally. L. chuanxiong has the characteristic of male infertility, which is an important reason for its sexual reproductive disorders.

HD-Zip proteins modify floral structures for self-pollination in tomato.

Cleistogamy is a type of self-pollination that relies on the formation of a stigma-enclosing floral structure. We identify three homeodomain-leucine zipper IV (HD-Zip IV) genes that coordinately promote the formation of interlocking trichomes at the anther margin to unite neighboring anthers, generating a closed anther cone and cleistogamy (flower morphology necessitating strict self-pollination). These HD-Zip IV genes also control style length by regulating the transition from cell division to endoreduplication. The expression of these HD-Zip IV genes and their downstream gene, Style 2.1, was sequentially modified to shape the cleistogamy morphology during tomato evolution and domestication. Our results provide insights into the molecular basis of cleistogamy in modern tomato and suggest targets for improving fruit set and preventing pollen contamination in genetically modified crops.

Green Synthesis of Zinc Oxide Nanoparticles from Althaea officinalis Flower Extract Coated with Chitosan for Potential Healing Effects on Diabetic Wounds by Inhibiting TNF-α and IL-6/IL-1ß Signaling Pathways.

Background: Diabetes Mellitus is a multisystem chronic pandemic, wound inflammation, and healing are still major issues for diabetic patients who may suffer from ulcers, gangrene, and other wounds from uncontrolled chronic hyperglycemia. Marshmallows or Althaea officinalis (A.O.) contain bioactive compounds such as flavonoids and phenolics that support wound healing via antioxidant, anti-inflammatory, and antibacterial properties. Our study aimed to develop a combination of eco-friendly formulations of green synthesis of ZnO-NPs by Althaea officinalis extract and further incorporate them into 2% chitosan (CS) gel. Method and Results: First, develop eco-friendly green Zinc Oxide Nanoparticles (ZnO-NPs) and incorporate them into a 2% chitosan (CS) gel. In-vitro study performed by UV-visible spectrum analysis showed a sharp peak at 390 nm, and Energy-dispersive X-ray (EDX) spectrometry showed a peak of zinc and oxygen. Besides, Fourier transforms infrared (FTIR) was used to qualitatively validate biosynthesized ZnO-NPs, and transmission electron microscope (TEM) showed spherical nanoparticles with mean sizes of 76 nm and Zeta potential +30mV. The antibacterial potential of A.O.-ZnO-NPs-Cs was examined by the diffusion agar method against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Based on the zone of inhibition and minimal inhibitory indices (MIC). In addition, an in-silico study investigated the binding affinity of A.O. major components to the expected biological targets that may aid wound healing. Althaea Officinalis, A.O-ZnO-NPs group showed reduced downregulation of IL-6, IL-1ß, and TNF-α and increased IL-10 levels compared to the control group signaling pathway expression levels confirming the improved anti-inflammatory effect of the self-assembly method. In-vivo study and histopathological analysis revealed the superiority of the nanoparticles in reducing signs of inflammation and wound incision in rat models. Conclusion: These biocompatible green zinc oxide nanoparticles, by using Althaea Officinalis chitosan gel ensure an excellent new therapeutic approach for quickening diabetic wound healing.

Continuous mowing differentially affects floral defenses in the noxious and invasive weed Solanum elaeagnifolium in its native range.

In weeds, disturbance has been found to affect life history traits and mediate trophic interactions. In urban landscapes, mowing is an important disturbance, and we previously showed that continuous mowing leads to enhanced fitness and defense traits in Solanum elaeagnifolium, Silverleaf Nightshade (SLN). However, most studies have been focused on foliar defenses, ignoring floral defenses. In this study we examined whether continuous mowing affected floral defenses in SLN using mowed and unmowed populations in South Texas, their native range. We found flowers of mowed SLN plants larger but lighter than unmowed plants. Additionally, flowers on plants that were mowed frequently were both heavier and larger. Mowed plants had higher spine density and consequently unmowed flowers had higher herbivore damage. Additionally, early instar Manduca sexta fed on mowed flower-based artificial diets showed no difference in mass than the control and unmowed; however, later instars caterpillars on unmowed diets gained significantly more mass than the mowed treatment and control. Mowed plants had higher spine density which may shed light on why unmowed flowers experienced higher herbivore damage. We found caterpillars fed on high mowing frequency diets were heavier than those on low mowing frequency diets. Collectively, we show that mowing compromises floral traits and enhances plant defenses against herbivores and should be accounted for in management.

Identification of microRNAs and their target genes associated with chasmogamous and cleistogamous flower development in Viola prionantha.

MAIN CONCLUSION: Differentially expressed microRNAs were found associated with the development of chasmogamous and cleistogamous flowers in Viola prionantha, revealing potential roles of microRNAs in the developmental evolution of dimorphic flowers. In Viola prionantha, chasmogamous (CH) flowers are induced by short daylight, while cleistogamous (CL) flowers are triggered by long daylight. How environmental factors and microRNAs (miRNAs) affect dimorphic flower formation remains unknown. In this study, small RNA sequencing was performed on CH and CL floral buds at different developmental stages in V. prionantha, differentially expressed miRNAs (DEmiRNAs) were identified, and their target genes were predicted. In CL flowers, Viola prionantha miR393 (vpr-miR393a/b) and vpr-miRN3366 were highly expressed, while in CH flowers, vpr-miRN2005, vpr-miR172e-2, vpr-miR166m-3, vpr-miR396f-2, and vpr-miR482d-2 were highly expressed. In the auxin-activated signaling pathway, vpr-miR393a/b and vpr-miRN2005 could target Vpr-TIR1/AFB and Vpr-ARF2, respectively, and other DEmiRNAs could target genes involved in the regulation of transcription, e.g., Vpr-AP2-7. Moreover, Vpr-UFO and Vpr-YAB5, the main regulators in petal and stamen development, were co-expressed with Vpr-TIR1/AFB and Vpr-ARF2 and showed lower expression in CL flowers than in CH flowers. Some V. prionantha genes relating to the stress/defense responses were co-expressed with Vpr-TIR1/AFB, Vpr-ARF2, and Vpr-AP2-7 and highly expressed in CL flowers. Therefore, in V. prionantha, CH-CL flower development may be regulated by the identified DEmiRNAs and their target genes, thus providing the first insight into the formation of dimorphic flowers in Viola.

RuBisCO Depletion and Subcellular Fractionation for Enhanced Florigen Detection in Arabidopsis.

In plants, complex signaling networks monitor and respond to environmental cues to determine the optimal time for the transition from the vegetative to reproductive phase. Understanding these networks requires robust tools to examine the levels and subcellular localization of key factors. The florigen FLOWERING LOCUS T (FT) is a crucial regulator of flowering time and occurs in soluble and membrane-bound forms. At low ambient temperatures, the ratio of these forms of FT undergoes a significant shift, which leads to a delay in the onset of flowering. To investigate these changes in FT localization, epitope-tagged FT protein can be isolated from plants by subcellular fractionation and its localization examined by immunoblot analysis of the resulting fractions. However, the highly abundant protein ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) can interfere with methods to detect and characterize low-abundance proteins such as FT. In this chapter, we present a method for analyzing the ratio of HA-tagged FT (HA:FT) in different subcellular fractions while mitigating the interference from RuBisCO by using protamine sulfate (PS) to deplete RuBisCO during protein purification, thereby enhancing HA:FT detection in fractionated samples.

Spillover effects from invasive Acacia alter the plant-pollinator networks and seed production of native plants.

Invasive flowering plants can disrupt plant-pollinator networks. This is well documented where invasives occur amongst native plants; however, the potential for 'spillover' effects of invasives that form stands in adjacent habitats are less well understood. Here we quantify the impact of two invasive Australian species, Acacia saligna and Acacia longifolia, on the plant-pollinator networks in fynbos habitats in South Africa. We compared networks from replicate 1 ha plots of native vegetation (n = 21) that were subjected to three treatments: (1) at least 400 m from flowering Acacia; (2) adjacent to flowering Acacia, or (3) adjacent to flowering Acacia where all Acacia flowers were manually removed. We found that native flowers adjacent to stands of flowering Acacia received significantly more insect visits, especially from beetles and Apis mellifera capensis, and that visitation was more generalized. We also recorded visitation to, and the seed set of, three native flowering species and found that two received more insect visits, but produced fewer seeds, when adjacent to flowering Acacia. Our research shows that 'spillover' effects of invasive Acacia can lead to significant changes in visitation and seed production of native co-flowering species in neighbouring habitats-a factor to be considered when managing invaded landscapes.

Cretaceous chloranthoids: early prominence, extinct diversity and missing links.

BACKGROUND: The Chloranthaceae comprise four extant genera (Hedyosmum, Ascarina, Chloranthus and Sarcandra), all with simple flowers. Molecular phylogenetics indicates that the Chloranthaceae diverged very early in angiosperm evolution, although how they are related to eudicots, magnoliids, monocots and Ceratophyllum is uncertain. Fossil pollen similar to that of Ascarina and Hedyosmum has long been recognized in the Early Cretaceous, but over the last four decades evidence of extinct Chloranthaceae based on other types of fossils has expanded dramatically and contributes significantly to understanding the evolution of the family. SCOPE: Studies of fossils from the Cretaceous, especially mesofossils of Early Cretaceous age from Portugal and eastern North America, recognized diverse flowers, fruits, seeds, staminate inflorescences and stamens of extinct chloranthoids. These early chloranthoids include forms related to extant Hedyosmum and also to the Ascarina, Chloranthus and Sarcandra clade. In the Late Cretaceous there are several occurrences of distinctive fossil androecia related to extant Chloranthus. The rich and still expanding Cretaceous record of Chloranthaceae contrasts with a very sparse Cenozoic record, emphasizing that the four extant genera are likely to be relictual, although speciation within the genera might have occurred in relatively recent times. In this study, we describe three new genera of Early Cretaceous chloranthoids and summarize current knowledge on the extinct diversity of the group. CONCLUSIONS: The evolutionary lineage that includes extant Chloranthaceae is diverse and abundantly represented in Early Cretaceous mesofossil floras that provide some of the earliest evidence of angiosperm reproductive structures. Extinct chloranthoids, some of which are clearly in the Chloranthaceae crown group, fill some of the morphological gaps that currently separate the extant genera, help to illuminate how some of the unusual features of extant Chloranthaceae evolved and suggest that Chloranthaceae are of disproportionate importance for a more refined understanding of ecology and phylogeny of early angiosperm diversification.

Molecular mechanisms of self-incompatibility in Brassicaceae and Solanaceae.

Self-incompatibility (SI) is a mechanism for preventing self-fertilization in flowering plants. SI is controlled by a single S-locus with multiple haplotypes (S-haplotypes). When the pistil and pollen share the same S-haplotype, the pollen is recognized as self and rejected by the pistil. This review introduces our research on Brassicaceae and Solanaceae SI systems to identify the S-determinants encoded at the S-locus and uncover the mechanisms of self/nonself-discrimination and pollen rejection. The recognition mechanisms of SI systems differ between these families. A self-recognition system is adopted by Brassicaceae, whereas a collaborative nonself-recognition system is used by Solanaceae. Work by our group and subsequent studies indicate that plants have evolved diverse SI systems.

A Long-Lived Alpine Perennial Advances Flowering under Warmer Conditions but Not Enough to Maintain Reproductive Success.

AbstractAssessing whether phenological shifts in response to climate change confer a fitness advantage requires investigating the relationships among phenology, fitness, and environmental drivers of selection. Despite widely documented advancements in phenology with warming climate, we lack empirical estimates of how selection on phenology varies in response to continuous climate drivers or how phenological shifts in response to warming conditions affect fitness. We leverage an unusual long-term dataset with repeated, individual measurements of phenology and reproduction in a long-lived alpine plant. We analyze phenotypic plasticity in flowering phenology in relation to two climate drivers, snowmelt timing and growing degree days (GDDs). Plants flower earlier with increased GDDs and earlier snowmelt, and directional selection also favors earlier flowering under these conditions. However, reproduction still declines with warming and early snowmelt, even when flowering is early. Furthermore, the steepness of this reproductive decline increases dramatically with warming conditions, resulting in very little fruit production regardless of flowering time once GDDs exceed approximately 225 degree days or snowmelt occurs before May 15. Even though advancing phenology confers a fitness advantage relative to stasis, these shifts are insufficient to maintain reproduction under warming, highlighting limits to the potential benefits of phenological plasticity under climate change.

Comparative proteomic analysis of papaya bud flowers reveals metabolic signatures and pathways driving hermaphrodite development.

Papaya (Carica papaya) is a trioecious species with female, male, and hermaphrodite plants. Given the sex segregation, selecting hermaphroditic plants is vital for orchard establishment due to their greater commercial value. However, selecting hermaphrodite plants through sexing is laborious and costly. Moreover, environmental stressors can exacerbate the issue by potentially inducing abnormal flower development, thus affecting fruit quality. Despite these challenges, the molecular mechanisms governing sex development in papaya remain poorly understood. Thus, this study aimed to identify proteins associated with sex development in female and hermaphrodite flowers of papaya through comparative proteomic analysis. Proteins from flower buds at the early and late developmental stages of three papaya genotypes (UENF-CALIMAN 01, JS12, and Sunrise Solo 72/12) were studied via proteomic analysis via the combination of the shotgun method and nanoESI-HDMSE technology. In buds at an early stage of development, 496 (35.9%) proteins exhibited significantly different abundances between sexes for the SS72/12 genotype, 139 (10%) for the JS12 genotype, and 165 (11.9%) for the UC-01 genotype. At the final stage of development, there were 181 (13.5%) for SS72/12, 113 (8.4%) for JS12, and 125 (9.1%) for UC-01. The large group of differentially accumulated proteins (DAPs) between the sexes was related to metabolism, as shown by the observation of only the proteins that exhibited the same pattern of accumulation in the three genotypes. Specifically, carbohydrate metabolism proteins were up-regulated in hermaphrodite flower buds early in development, while those linked to monosaccharide and amino acid metabolism increased during late development. Enrichment of sporopollenin and phenylpropanoid biosynthesis pathways characterizes hermaphrodite samples across developmental stages, with predicted protein interactions highlighting the crucial role of phenylpropanoids in sporopollenin biosynthesis for pollen wall formation. Most of the DAPs played key roles in pectin, cellulose, and lignin synthesis and were essential for cell wall formation and male flower structure development, notably in the pollen coat. These findings suggest that hermaphrodite flowers require more energy for development, likely due to complex pollen wall formation. Overall, these insights illuminate the molecular mechanisms of papaya floral development, revealing complex regulatory networks and energetic demands in the formation of male reproductive structures.

A novel O-methyltransferase Cp4MP-OMT catalyses the final step in the biosynthesis of the volatile 1,4-dimethoxybenzene in pumpkin (Cucurbita pepo) flowers.

BACKGROUND: Floral scents play a crucial role in attracting insect pollinators. Among the compounds attractive to pollinators is 1,4-dimethoxybenzene (1,4-DMB). It is a significant contributor to the scent profile of plants from various genera, including economically important Cucurbita species. Despite its importance, the biosynthetic pathway for the formation of 1,4-DMB was not elucidated so far. RESULTS: In this study we showed the catalysis of 1,4-DMB in the presence of 4-methoxyphenol (4-MP) by protein extract from Styrian oil pumpkin (Cucurbita pepo) flowers. Based on this finding, we identified a novel O-methyltransferase gene, Cp4MP-OMT, whose expression is highly upregulated in the volatile-producing tissue of pumpkin flowers when compared to vegetative tissues. OMT activity was verified by purified recombinant Cp4MP-OMT, illustrating its ability to catalyse the methylation of 4-MP to 1,4-DMB in the presence of cofactor SAM (S-(5'-adenosyl)-L-methionine). CONCLUSIONS: Cp4MP-OMT is a novel O-methyltransferase from C. pepo, responsible for the final step in the biosynthesis of the floral scent compound 1,4-DMB. Considering the significance of 1,4-DMB in attracting insects for pollination and in the further course fruit formation, enhanced understanding of its biosynthetic pathways holds great promise for both ecological insights and advancements in plant breeding initiatives.

Recovery of Cembratrien-Diols from Waste Tobacco (Nicotiana tabacum L.) Flowers by Microwave-Assisted Deep Eutectic Solvent Extraction: Optimization, Separation, and In Vitro Bioactivity.

Deep eutectic solvents (DESs) are novel solvents with physicochemical properties similar to those of ionic liquids, and they have attracted extensive attention for the extraction of bioactive compounds from different plant materials in the context of green chemistry and sustainable development. In this study, seven DESs with different polarities were explored as green extraction solvents for cembratrien-diols (CBT-diols) from waste tobacco flowers. The best solvent, DES-3 (choline chloride: lactic acid (1:3)), which outperformed conventional solvents (methanol, ethanol, and ethyl acetate), was selected and further optimized for microwave-assisted DES extraction using the response surface methodology. The maximum yield of CBT-diols (6.23 ± 0.15 mg/g) was achieved using a microwave power of 425 W, microwave time of 32 min, solid/liquid ratio of 20 mg/mL, and microwave temperature of 40 °C. Additionally, the isolated CBT-diols exhibited strong antimicrobial activity against Salmonella, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa and antitumor activity in the human liver cancer HepG2 and SMMC-7721 cell lines. This study highlights the feasibility of recovering CBT-diols from tobacco flower waste using DESs and provides opportunities for potential waste management using green technologies.

Floral visitors of sesame (Sesamum indicum L.): Elucidating their nectar-robbing behaviour and impacts on the plant reproduction.

Nectar robbing is common in angiosperms, especially in long tubular flowers or flowers with spurs that keep nectar out of reach of visitors. However, the robbing behaviour of bees is less understood. Here, we studied the sesame visitors, their robbing behaviour, and the impacts of robbing on plant reproductive fitness. Diverse insect species (primarily members of Hymenoptera) visited sesame flowers. The most effective pollinators were Amegilla zonata, Apis cerana, Apis dorsata, Apis florea, Ceratina binghami, Halictus acrocephalus and Xylocopa amethystina. Almost all visitors with variable percentages revealed the nectar-robbing phenomenon. Robbing activity depended on a complex of multiple attributes, including the visitor's body size, the corolla tube length, the availability and accessibility of nectar, and the resource-collecting task allocation of bees. Robbing activity varied according to flower-visiting species, flowering period and daytime. Robbing was comparatively higher in the late flowering period at 10.00-14.00 h. In the case of robbing visits, flower handling time was lower, and the visitation rate remained higher than non-robbing visits. Robbing visits did not significantly affect fruit and seed sets of sesame. Therefore, we can interpret the nectar-robbing interactions on sesame as commensal, with pollinators benefitting without altering the plant's reproductive fitness.