Effect of zinc oxide nanoparticles synthesized from Carya illinoinensis leaf extract on growth and antioxidant properties of mustard (Brassica juncea).

Background: The sustainability of crop production is impacted by climate change and land degradation, and the advanced application of nanotechnology is of paramount importance to overcome this challenge. The development of nanomaterials based on essential nutrients like zinc could serve as a basis for nanofertilizers and nanocomposite synthesis for broader agricultural applications and quality human nutrition. Therefore, this study aimed to synthesize zinc oxide nanoparticles (ZnO NPs) using pecan (Carya illinoinensis) leaf extract and investigate their effect on the growth, physiology, nutrient content, and antioxidant properties of mustard (Brassica juncea). Methods: The ZnO NPs were characterized by UV-Vis spectrophotometry, Dynamic Light Scattering (DLS), X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infra-Red Spectroscopy (FTIR). Mustard plants were subjected to different concentrations of ZnONPs (0, 20, 40, 60, 80, 100 and 200 mg L-1) during the vegetative growth stage. Results: The UV-Vis spectra of ZnO NPs revealed the absorption maxima at 362 nm and FTIR identified numerous functional groups that are responsible for capping and stabilizing ZnO NPs. DLS analysis presented monodispersed ZnO NPs of 84.5 nm size and highly negative zeta potential (-22.4 mV). Overall, the application of ZnO NPs enhanced the growth, chlorophyll content (by 53 %), relative water content (by 46 %), shoot biomass, membrane stability (by 54 %) and net photosynthesis significantly in a dose-dependent manner. In addition, the supplement of the ZnO NPs augmented K, Fe, Zn and flavonoid contents as well as overcome the effect of reactive oxygen species by increasing antioxidant capacity in mustard leaves up to 97 %. Conclusions: In conclusion, ZnO NPs can be potentially used as a plant growth stimulant and as a novel soil amendment for enhancing crop yields. Besides, the biofortification of B. juncea plants with ZnO NPs helps to improve the nutritional quality of the crop and perhaps potentiates its pharmaceutical effects.

The silicon regulates microbiome diversity and plant defenses during cold stress in Glycine max L.

Introduction: With climate change, frequent exposure of bioenergy and food crops, specifically soybean (Glycine max L.), to low-temperature episodes is a major obstacle in maintaining sustainable plant growth at early growth stages. Silicon (Si) is a quasi-essential nutrient that can help to improve stress tolerance; however, how Si and a combination of cold stress episodes influence plant growth, plant physiology, and microbiome diversity has yet to be fully discovered. Methods: The soybean plants were exposed to cold stress (8-10°C) with or without applying Si, and the different plant organs (shoot and root) and rhizospheric soil were subjected to microbiome analysis. The plant growth, physiology, and gene expression analysis of plant defenses during stress and Si were investigated. Results and discussion: We showed that cold stress significantly retarded soybean plants' growth and biomass, whereas, Si-treated plants showed ameliorated negative impacts on plant growth at early seedling stages. The beneficial effects of Si were also evident from significantly reduced antioxidant activities - suggesting lower cold-induced oxidative stress. Interestingly, Si also downregulated critical genes of the abscisic acid pathway and osmotic regulation (9-cis-epoxy carotenoid dioxygenase and dehydration-responsive element binding protein) during cold stress. Si positively influenced alpha and beta diversities of bacterial and fungal microbiomes with or without cold stress. Results showed significant variation in microbiome composition in the rhizosphere (root and soil) and phyllosphere (shoot) in Si-treated plants with or without cold stress exposures. Among microbiome phyla, Proteobacteria, Bacteroidota, and Ascomycota were significantly more abundant in Si treatments in cold stress than in control conditions. For the core microbiome, we identified 179 taxa, including 88 unique bacterial genera in which Edaphobacter, Haliangium, and Streptomyces were highly abundant. Enhanced extracellular enzyme activities in the cold and Si+cold treatments, specifically phosphatase and glucosidases, also reflected the microbiome abundance. In conclusion, this work elucidates cold-mediated changes in microbiome diversity and plant growth, including the positive impact Si can have on cold tolerance at early soybean growth stages - a step toward understanding crop productivity and stress tolerance.

The morphological and anatomical variability of the stems of an industrial hemp collection and the properties of its fibres.

Industrial hemp (Cannabis sativa L.) is identified as a leading fibre crop and there is increasing interest in C. sativa fibre due to its new range of industrial applications. However, the complexity of hemp germplasm resulted in insufficient information on the effect of genotypes on fibre quality and quantity. In this study, 16 fibre and non-fibre type hemp genotypes were evaluated to compare the morpho-anatomical differences of stems and physico-mechanical fibre properties under three retting methods and to understand the effect of stem colour on the properties of hemp fibres. Morphological markers were scored and stem anatomy was examined using live and herbarium collections. Stems were retted using chemical, enzymatic, and microbiological methods. The resulting fibres were tested for tensile strength, moisture retention, colour, bast and hurd dry weights. Hemp genotypes showed morphological variations that affect fibre processing and a unique pattern of fibre wedges in cross-sections of the basal internode. Fibre yield, tensile strength, colour, and moisture retention significantly varied among the genotypes. The hemp collection used in this study formed three clusters in principal component analysis and traits such as internodal length, node number, hurd yield, and tensile strength highly contributed to the total variability. Additionally, non-fibre type hemp genotypes that showed important fibre properties were identified. The hemp genotypes that were selected based on our approaches can be tailored towards the specificities of the end-usage of choice. Our methods will enable the exploration of hemp genetic diversity pertaining to fibre properties and contribute to the preliminary identification of genotypes as a supplement to genetic analyses.

Plant based radioprotectors as an adjunct to radiotherapy: advantages and limitations.

Radioprotectors are agents that have the potential to act against radiation damage to cells. These are equally invaluable in radiation protection, both in intentional and unintentional radiation exposure. It is however, complex to use a universal radioprotector that could be beneficial in diverse contexts such as in radiotherapy, nuclear accidents, and space travel, as each of these circumstances have unique requirements. In a clinical setting such as in radiotherapy, a radioprotector is used to increase the efficacy of cancer treatment. The protective agent must act against radiation damage selectively in normal healthy cells while enhancing the radiation damage imparted on cancer cells. In the context of radiotherapy, plant-based compounds offer a more reliable solution over synthetic ones as the former are less expensive, less toxic, possess synergistic phytochemical activity, and are environmentally friendly. Phytochemicals with both radioprotective and anticancer properties may enhance the treatment efficacy by two-fold. Hence, plant based radioprotective agents offer a promising field to progress forward, and to expand the boundaries of radiation protection. This review is an account on radioprotective properties of phytochemicals and complications encountered in the development of the ideal radioprotector to be used as an adjunct in radiotherapy.

Green Synthesis of Silver Nanoparticles with Antimicrobial Properties Using Phyla dulcis Plant Extract.

Foodborne illnesses caused by the consumption of food contaminated with foodborne pathogens at infectious doses are becoming a common health issue throughout the world. Metal nanoparticles with potential antimicrobial properties are an area that can be explored to discover novel antimicrobial agents. The traditional synthesis methods of metal nanoparticles involve the use of toxic chemicals and the generation of harmful byproducts. In this study, a greener method to synthesize silver nanoparticles (AgNPs) with potential antimicrobial properties was investigated. The aqueous extract of the medicinal plant Phyla dulcis Trev. (verbenaceae) was used as the reducing and stabilizing agent to synthesize AgNPs using microwave irradiation. The formation of AgNPs was confirmed using ultraviolet-visible spectroscopy by the appearance of characteristic surface plasmon resonance peaks in the 430-440 nm wavelength range. The size and stability of the AgNPs were studied using Zetasizer nano-series for 5 weeks after synthesis. The average particle size remained between 63 and 76 nm during the first 4 weeks and increased to 114 nm in the fifth week showing possible aggregation after the fourth week. The zeta potential remained between -20 and -24 mV throughout the 5 weeks showing relatively good stability. Scanning electron microscopy/energy dispersive X-ray spectroscopy showed the association of phytoconstituents with the AgNPs. X-ray photoelectron spectroscopy analysis confirmed the formation of metallic nanoparticles starting from silver nitrate. Finally, the AgNPs were tested to be effective against Escherichia coli O157:H7 (ATCC 43888), Salmonella Typhimurium (novobiocin and nalidixic acid resistant strain), Listeria monocytogenes (4b; ATCC 19115), and Staphylococcus aureus (ATCC 6538) strains, which are known to be common foodborne pathogens.

Comparative study of three Plumbago L. species (Plumbaginaceae) by microscopy, UPLC-UV and HPTLC.

This paper presents a comparative study of anatomy of leaves, stems and roots of three species of Plumbago, namely P. auriculata Lam., P. indica L. and P. zeylanica L. by light microscopy. The paper also provides qualitative and quantitative analysis of the naphthoquinone, plumbagin-a major constituent present in these species-using UPLC-UV. Microscopic examinations revealed the presence of distinctive differences in the anatomical features of the leaf, stem and root of the three species, and these can thus be used for identification and authentication of these species. UPLC-UV analysis showed the highest concentration of plumbagin in the roots of P. zeylanica (1.62% w/w) followed by the roots of P. indica (0.97% w/w) and then P. auriculata (0.33-0.53% w/w). In contrast, plumbagin was not detected in the stems and leaves of P. indica and in the leaves of P. auriculata, whereas very low concentrations (<0.02% w/w) of plumbagin were detected in the stems and leaves of P. zeylanica and in the stems of P. auriculata. HPTLC fingerprints of the leaf and root of the three species exhibited distinguishable profiles, while those of the stems were undifferentiated.

Functional identification of valerena-1,10-diene synthase, a terpene synthase catalyzing a unique chemical cascade in the biosynthesis of biologically active sesquiterpenes in Valeriana officinalis.

Valerian is an herbal preparation from the roots of Valeriana officinalis used as an anxiolytic and sedative and in the treatment of insomnia. The biological activities of valerian are attributed to valerenic acid and its putative biosynthetic precursor valerenadiene, sesquiterpenes, found in V. officinalis roots. These sesquiterpenes retain an isobutenyl side chain whose origin has been long recognized as enigmatic because a chemical rationalization for their biosynthesis has not been obvious. Using recently developed metabolomic and transcriptomic resources, we identified seven V. officinalis terpene synthase genes (VoTPSs), two that were functionally characterized as monoterpene synthases and three that preferred farnesyl diphosphate, the substrate for sesquiterpene synthases. The reaction products for two of the sesquiterpene synthases exhibiting root-specific expression were characterized by a combination of GC-MS and NMR in comparison to the terpenes accumulating in planta. VoTPS7 encodes for a synthase that biosynthesizes predominately germacrene C, whereas VoTPS1 catalyzes the conversion of farnesyl diphosphate to valerena-1,10-diene. Using a yeast expression system, specific labeled [(13)C]acetate, and NMR, we investigated the catalytic mechanism for VoTPS1 and provide evidence for the involvement of a caryophyllenyl carbocation, a cyclobutyl intermediate, in the biosynthesis of valerena-1,10-diene. We suggest a similar mechanism for the biosynthesis of several other biologically related isobutenyl-containing sesquiterpenes.

A new triterpene glycoside from Centella erecta.

A new (2α,3ß)-23-sulphonyl-2,3-dihydroxyurs-12-en-28-oic acid O-α-L-rhamnopyranosyl-(1 → 4)-O-ß-D-glucopyranosyl-(1 → 6)-O-ß-D-glucopyranosyl ester (1) together with eighteen known compounds were isolated from Centella erecta (L.f.) Fern. Their structures were elucidated mainly by NMR and HRESIMS, as well as on comparison with the reported data.

Two new triterpene glycosides from Centella asiatica.

Phytochemical investigation of the leaves of Centella asiatica resulted in the isolation and characterization of eight triterpenes and/or saponins [which were characterized as 23- O-acetylmadecassoside (1), asiatic acid (2), madecassic acid (3), asiaticoside C (4), asiaticoside F (5), asiaticoside (6), madecassoside (7), and 23- O-acetylasiaticoside B (8)] together with sitosterol 3-O-beta-glucoside ( 9), stigmasterol 3- O- beta-glucoside (10), and querectin-3- O-beta-D-glucuronide (11). A new ursane-derived saponin (23- O-acetylmadecassoside) and a new oleanane-derived saponin (23- O-acetylasiaticoside B) were found as well. Structure elucidation was done by using spectroscopic techniques (HR-ESI-MS, 1D and 2D NMR), chemical methods, and comparative literature studies.