Integrated analyses of ionomics, phytohormone profiles, transcriptomics, and metabolomics reveal a pivotal role of carbon-nano sol in promoting the growth of tobacco plants.

BACKGROUND: Carbon nano sol (CNS) can markedly affect the plant growth and development. However, few systematic analyses have been conducted on the underlying regulatory mechanisms in plants, including tobacco (Nicotiana tabacum L.). RESULTS: Integrated analyses of phenome, ionome, transcriptome, and metabolome were performed in this study to elucidate the physiological and molecular mechanisms underlying the CNS-promoting growth of tobacco plants. We found that 0.3% CNS, facilitating the shoot and root growth of tobacco plants, significantly increased shoot potassium concentrations. Antioxidant, metabolite, and phytohormone profiles showed that 0.3% CNS obviously reduced reactive oxygen species production and increased antioxidant enzyme activity and auxin accumulation. Comparative transcriptomics revealed that the GO and KEGG terms involving responses to oxidative stress, DNA binding, and photosynthesis were highly enriched in response to exogenous CNS application. Differential expression profiling showed that NtNPF7.3/NtNRT1.5, potentially involved in potassium/auxin transport, was significantly upregulated under the 0.3% CNS treatment. High-resolution metabolic fingerprints showed that 141 and 163 metabolites, some of which were proposed as growth regulators, were differentially accumulated in the roots and shoots under the 0.3% CNS treatment, respectively. CONCLUSIONS: Taken together, this study revealed the physiological and molecular mechanism underlying CNS-mediated growth promotion in tobacco plants, and these findings provide potential support for improving plant growth through the use of CNS.

Leaf grey spot caused by Arcopilus aureus on tobacco in China.

Tobacco (Nicotiana tabacum L.) is one of the most widely cultivated industrial crops worldwide. From April to July 2023, about 40% of tobacco seedlings in the greenhouse exhibited irregular taupe lesions in Zhengzhou, Henan Province, China. At an early stage of the lesion development, light grey spots with the diameter of 1-2 mm were observed, these spots gradually expanded and connected into large irregular lesions causing leaf wrinkling or withered. A total of 12 infected leaf tissues were sterilized with 75% ethanol for 45 s, rinsed three times in sterilized water and then plated on potato dextrose agar (PDA) medium for 10 days at 28°C in darkness. Seven fungal colonies that show the similar appearance were isolated and three of them (MB-1, MB-2 and MB-3) were used for subsequent identification. Colonies of these strains on PDA with loose mycelium and orange-red pigment on the underside, white aerial in the center and light yellow hyphae near the periphery, formed in the shape of a concentric ring pattern. Ascomata appeared from the 14th day, were black, spherical or ellipsoid with walls of textura angularis, and size was 53.8-101.1 µm × 50.3-104.3 µm (n=30). Terminal hairs were brown and straight, gradually tapering toward the tips. Asci clavate or fusiform, spore bearing part 16.2-29.2 × 7.3-11.4 µm (n=21), with 8 irregularly arranged ascospores, evanescent. Ascospores are brown at maturity, biapiculate, navicular or fusiform shapes with size of 8.7-12.8 µm × 4.8-6.9 µm (n=100), and more or less inaequilateral. Single spore strains derived from these strains exhibited the morphological features consistent with the original strains. The morphological characteristics of the fungus were consistent with the description of Arcopilus aureus (Chivers) X.W. Wang & Samson (= Chaetomium aureum Chivers) (Lee et al. 2019). Furthermore, the sequences of RPB2 region were amplified from these strains and the result sequences (GenBank accession no. OR513105-OR513108) all showed a 100.00% identity with A. aureus strain CBS 538.73 (GenBank accession no. KX976807.1). It was reported that the RPB2 gene was efficient in discriminating Arcopilus species (Tavares et al. 2022), thus a maximum likelihood (ML) phylogenetic tree based on the RPB2 gene sequences were constructed using MEGA 7.0 with 1000 replications of bootstrapping (Kumar et al. 2016), which revealed that these strains formed a well-supported clade with A. aureus strains of (CBS 153.52 and CBS538.73) (Wang et al. 2022). Pathogenicity analysis were performed on healthy flue-cured tobacco seedlings leaves (cv Y85) by using mycelial agar plugs (5 mm in diameter) and spore suspension (1×106 spores/mL), and the PDA plugs and sterile water were used for control group, respectively. Tobacco seedlings were incubated in a 25°C and 70% RH growth chamber. After seven days, the leaves showed obvious symptoms, with taupe lesions and yellow halos on the periphery, whereas no symptoms were found on the control leaves. The A. aureu was then reisolated from inoculated diseased leaves. Previously, A. aureus has been only reported to cause leaf black disease on Pseudostellaria heterophylla in China (Yuan et al. 2021). To our knowledge, this is the first reported of A. aureus causing tobacco leaf grey spot worldwide. Arcopilus aureus has been reported as a plant biocontrol fungus (Wang et al. 2013). However, due to the potential serious damage in tobacco seedlings caused by this fungus, the use of A. aureus as a plant biocontrol agent needs to be given more attention, and disease control measures of this pathogen should be developed.

Carbon nanosol-induced assemblage of a plant-beneficial microbiome consortium.

Carbon nanosol (CNS) is a carbon-based nanomaterial that promotes plant growth; however, its functional mechanisms and effects on the microbiome are not fully understood. Here, we explored the effects of CNS on the relationship between the soil, endophytic microbiomes and plant productivity. CNS treatment increased the fresh biomass of tobacco (Nicotiana tabacum L.) plants by 27.4% ± 9.9%. Amplicon sequencing analysis showed that the CNS treatment significantly affected the composition and diversity of the microbial communities in multiple ecological niches associated with tobacco, especially the bulk soil and stem endophytic microbiome. Furthermore, the application of CNS resulted in enhanced network connectivity and stability of the microbial communities in different niches, particularly in the soil, implying a strengthening of certain microbial interactions. Certain potentially growth-promoting root endophytic bacteria were more abundant under the CNS treatment. In addition, CNS increased the abundance of some endophytic microbial functional genes known to enhance plant growth, such as those associated with nutrient metabolism and the plant hormone biosynthesis pathways. We isolated two bacterial strains (Sphingopyxis sp. and Novosphingobium sp.) that were enriched under CNS treatment, and they were confirmed to promote tobacco plant growth in vitro. These results suggested that CNS might, at least in part, promote plant growth by enriching beneficial bacteria in the microbiome.

Effects of functional carbon nanodots on water hyacinth response to Cd/Pb stress: Implication for phytoremediation.

Phytoremediation is one of the effective, economic and green approaches to cope with the increasing worldwide heavy metal (HM) pollution. Here, we evaluate the effects of functional carbon nanodots (FCNs) against the hyperaccumulation capacity as well as the physiological and genetic responses of water hyacinth under Pb2+ or/and Cd2+ stress. The bioaccumulation efficiency, HM content and transfer factor, biomass, root development, chlorophyll content, antioxidant system and genes expression are investigated at various concentration of HMs. Based on the excellent adsorption capacity and plant growth regulation ability, FCNs and nitrogen doped FCNs (N-FCNs) cooperate with water hyacinth to improve their HMs removal efficiencies. FCNs and N-FCNs immobilize excess HMs ions in plant, smartly regulate enzymatic levels to mitigate oxidative damage, as well as regulate the microelement uptake and related gene expression, thus improve plant tolerance against HMs stress. Although Pb and Cd have antagonistic effects on bioaccumulation of water hyacinth to the single metal, FCNs and N-FCNs can cooperate with water hyacinth to raise the removal efficiency of HMs in water, and enhance plant tolerance under Pb-Cd combined stress. The promotion effects of FCNs and N-FCNs on phytoremediation are more effective than conventional carbon nanomaterials, including carbon nanotubes and graphene oxides. These findings demonstrate that the application of FCNs or N-FCNs can improve the phytoremediation efficiency in the restoration of HMs contaminated water area. This study provides important insights into the possibility of using FCNs-based nanomaterials and water hyacinth as synergistic system for remediation of Cd-Pb contaminated water area.

Carbon nanoparticles enhance potassium uptake via upregulating potassium channel expression and imitating biological ion channels in BY-2 cells.

BACKGROUND: Carbon nanoparticles (CNPs) have been reported to boost plant growth, while the mechanism that CNPs enhanced potassium uptake for plant growth has not been reported so far. RESULTS: In this study, the function that CNPs promoted potassium uptake in BY-2 cells was established and the potassium accumulated in cells had a significant correlation with the fresh biomass of BY-2 cells. The K+ accumulation in cells increased with the increasing concentration of CNPs. The K+ influx reached high level after treatment with CNPs and was significantly higher than that of the control group and the negative group treated with K+ channels blocker, tetraethylammonium chloride (TEA+). The K+ accumulation was not reduced in the presence of CNPs inhibitors. In the presence of potassium channel blocker TEA+ or CNPs inhibitors, the NKT1 gene expression was changed compared with the control group. The CNPs were found to preferentially transport K+ than other cations determined by rectification of ion current assay (RIC) in a conical nanocapillary. CONCLUSIONS: These results indicated that CNPs upregulated potassium gene expression to enhance K+ accumulation in BY-2 cells. Moreover, it was speculated that the CNPs simulated protein of ion channels via bulk of carboxyl for K+ permeating. These findings will provide support for improving plant growth by carbon nanoparticles.

Continuous cropping system altered soil microbial communities and nutrient cycles.

Understanding the response of microbial communities and their potential functions is essential for sustainability of agroecosystems under long-term continuous cropping. However, limited research has focused on investigating the interaction between soil physicochemical factors and microbial community dynamics in agroecosystems under long-term continuous cropping. This study probed into the physicochemical properties, metabolites, and microbial diversity of tobacco rhizosphere soils cropped continuously for 0, 5, and 20 years. The relative abundance of bacterial genera associated with nutrient cycling (e.g., Sphingomonas) increased while potential plant pathogenic fungi and beneficial microorganisms showed synergistic increases with the duration of continuous cropping. Variations in soil pH, alkeline nitrogen (AN) content, and soil organic carbon (SOC) content drove the shifts in soil microbial composition. Metabolites such as palmitic acid, 3-hydroxypropionic acid, stearic acid, and hippuric acid may play a key role in soil acidification. Those results enhance our ability to predict shifts in soil microbial community structure associated with anthropogenic continuous cropping, which can have long-term implications for crop production.

Characteristics of soil microbial communities in farmland with different comprehensive fertility levels in the Panxi area, Sichuan, China.

Soil bacterial communities are intricately linked to ecosystem functioning, and understanding how communities assemble in response to environmental change is ecologically significant. Little is known about the assembly processes of bacteria communities across agro-ecosystems, particularly with regard to their environmental adaptation. To gain further insights into the microbial community characteristics of agro-ecosystems soil in the Panxi area of Sichuan Province and explore the key environmental factors driving the assembly process of the microbial community, this study conducted field sampling in major farmland areas of Panxi area and used Illumina MiSeq high-throughput sequencing technology to conduct bacterial sequencing. Soil organic matter (SOM), alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK) and other environmental factors were determined. The membership function method and principal component analysis method were used to evaluate the fertility of the soil. The results revealed minimal differences in alpha diversity index among samples with different comprehensive fertility indices, while NMDS analysis showed that community differences between species were mainly reflected in high fertility and low fertility (R: 0.068, p: 0.011). Proteobacteria, Acidobacteria and Actinobacteria were the main types of microbial communities, accounting for more than 60% of the relative abundance. Proteobacteria accounted for a higher proportion in the high fertility samples, while Acidobacteria and Actinobacteria accounted for a higher proportion in the middle and low fertility samples. Both the neutral theoretical model and zero model analysis showed that the microbial communities in tobacco-planting soil with different comprehensive fertility indices presented a random assembly process. With the increase in environmental distance difference, the diversity of the microbial community in medium and low-fertility soil also increased, but there was no significant change in high-fertility soil. Redundancy analysis showed that pH and SOM were the key factors affecting microbial community composition. The results of this study can provide a theoretical reference for the study of environmental factors and microbial communities in tobacco-growing soil.

Mechanistic basis for mitigating drought tolerance by selenium application in tobacco (Nicotiana tabacum L.): a multi-omics approach.

The lack of irrigation water in agricultural soils poses a significant constraint on global crop production. In-depth investigation into microRNAs (miRNAs) has been widely used to achieve a comprehensive understanding of plant defense mechanisms. However, there is limited knowledge on the association of miRNAs with drought tolerance in cigar tobacco. In this study, a hydroponic experiment was carried out to identify changes in plant physiological characteristics, miRNA expression and metabolite profile under drought stress, and examine the mitigating effects of selenium (Se) application. The shoot dry weight of drought-stressed plants was approximately half (50.3%) of that in non-stressed (control) conditions. However, plants supplied with Se attained 38.8% greater shoot dry weight as compared to plants with no Se supply under drought stress. Thirteen miRNAs were identified to be associated with drought tolerance. These included 7 known (such as nta-miR156b and nta-miR166a) and 6 novel miRNAs (such as novel-nta-miR156-5p and novel-nta-miR209-5p) with the target genes of squamosa promoter-binding-like protein 4 (SPL4), serine/threonine protein phosphatase 2A (PPP2A), cation/calcium exchanger 4-like (CCX4), extensin-1-like (EXT1) and reduced wall acetylation 2 (RWA2). Further investigation revealed that the expression levels of Ext1 and RWA2 were significantly decreased under drought stress but increased with Se addition. Moreover, key metabolites such as catechin and N-acetylneuraminic acid were identified, which may play a role in the regulation of drought tolerance. The integrated analysis of miRNA sequencing and metabolome highlighted the significance of the novel-nta-miR97-5p- LRR-RLK- catechin pathway in regulating drought tolerance. Our findings provide valuable insights into the molecular mechanisms underlying drought tolerance and Se-induced stress alleviation in cigar tobacco.

Alleviation role of functional carbon nanodots for tomato growth and soil environment under drought stress.

The biotoxicity and environmental applications of carbon nanomaterials have always been the focus of research. In this research, functional carbon nanodots (FCNs) show high promotion effects on regulating the growth, development and yield of tomato under drought stress, due to their up-regulation effects on the physiological processes of plants including photosynthesis, antioxidant system, osmotic adjustment, as well as soil amelioration in physicochemical properties and microbial environment during vegetative and reproductive growth stage. The reduction of tissue water content and water use efficiency are moderated by FCNs through improving root vigor and osmolytes (soluble sugar and proline) level, which contributes to maintain the enzyme function, photosynthesis and nutrient uptake in plant. FCNs regulate the enzymatic and non-enzymatic antioxidant system to scavenge reactive oxygen species (ROS) and inhibit the lipid peroxidation, thus protect the membrane structure and function of plant cells under stress. FCNs up-regulate soil microbial communities under drought stress by regulating the soil pH, enzyme activity, organic carbon and organic matters contents. Our results prove that FCNs are biological friendly to plant growth and soil environment under drought stress, thus exhibit potential as emendator to promote plant tolerance and improve agricultural productivity in water-deficient areas.

Identification and Expression Profiles of Putative Soluble Chemoreception Proteins from Lasioderma serricorne (Coleoptera: Anobiidae) Antennal Transcriptome.

The cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), is a destructive stored product pest worldwide. Adult cigarette beetles are known to rely on host volatiles and pheromones to locate suitable habitats for oviposition and mating, respectively. However, little is known about the chemosensory mechanisms of these pests. Soluble chemoreception proteins are believed to initiate olfactory signal transduction in insects, which play important roles in host searching and mating behaviors. In this study, we sequenced the antennal transcriptome of L. serricorne and identified 14 odorant-binding proteins (OBPs), 5 chemosensory proteins (CSPs), and 2 Niemann-Pick C2 proteins (NPC2). Quantitative realtime PCR (qPCR) results revealed that several genes (LserOBP2, 3, 6, and 14) were predominantly expressed in females, which might be involved in specific functions in this gender. The five LserOBPs (LserOBP1, 4, 8, 10, and 12) that were highly expressed in the male antennae might encode proteins involved in specific functions in males. These findings will contribute to a better understanding of the olfactory system in this stored product pest and will assist in the development of efficient and environmentally friendly strategies for controlling L. serricorne.

A Stretchable and Safe Polymer Electrolyte with a Protecting-Layer Strategy for Solid-State Lithium Metal Batteries.

An elastic and safe electrolyte is demanded for flexible batteries. Herein, a stretchable solid electrolyte comprised of crosslinked elastic polymer matrix, poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), and flameproof triethyl phosphate (TEP) is fabricated, which exhibits ultrahigh elongation of 450%, nonflammability and ionic conductivity above 1 mS cm-1. In addition, in order to improve the interface compatibility between the electrolyte and Li anode and stabilize the solid-electrolyte interphase (SEI), a protecting layer containing poly(ethylene oxide) (PEO) is designed to effectively prevent the anode from reacting with TEP and optimize the chemical composition in SEI, leading to a tougher and more stable SEI on the anode. The LiFePO4/Li cells employing this double-layer electrolyte exhibit an 85.0% capacity retention after 300 cycles at 1 C. Moreover, a flexible battery based on this solid electrolyte is fabricated, which can work in stretched, folded, and twisted conditions. This design of a stretchable double-layer solid electrolyte provides a new concept for safe and flexible solid-state batteries.

Porous Polyamide Skeleton-Reinforced Solid-State Electrolyte: Enhanced Flexibility, Safety, and Electrochemical Performance.

The growing demand for safer lithium-ion batteries draws researchers' attention to solid-state electrolytes. In general, a desired electrolyte should be flexible, mechanically strong, and with high ionic conductivity. A solid-state electrolyte with a polymer as a matrix seems to be able to meet these demands. However, a pure polymer electrolyte lacks sufficient strength to suppress Li dendrites, and hybrids with ceramic components often lead to poor flexibility, both far from satisfactory. Herein, a solid-state electrolyte is designed by employing a mass-produced porous polyamide (PA) film infiltrated with polyethylene oxide (PEO)/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The PA/PEO/LiTFSI electrolyte is flexible but robust with a Young's modulus of up to 1030 MPa, ensuring steady Li//Li cycling without short circuit for more than 400 h. Also, the porous structure of the PA film decreases the crystalline regions and effectively enhances the ionic conductivity (2.05 × 10-4 S cm-1 at 30 °C). When cycled at 1C, solid-state LiFePO4//Li batteries assembled with the PA/PEO/LiTFSI electrolyte retain 82% capacity after 300 cycles (60 °C). In addition, a flexible LiFePO4//PA/PEO/LiTFSI//Li pouch cell can also work well in harsh operating environments, such as being folded, crimped, and pierced.

Improved Ionic Conductivity and Li Dendrite Suppression Capability toward Li7P3S11-Based Solid Electrolytes Triggered by Nb and O Cosubstitution.

It is still a big challenge to simultaneously enhance the ionic conductivity, dendrite suppression capability, and interfacial compatibility of sulfide solid electrolytes. In this work, a novel Li7P2.88Nb0.12S10.7O0.3 solid electrolyte is prepared via Nb and O cosubstitution of glass-ceramic Li7P3S11. This sulfide-based electrolyte possesses a high ionic conductivity (3.59 mS cm-1) at 298 K, improved critical current density (1.16 mA cm-2), and excellent interfacial compatibility between the sulfide electrolyte and Li2S active material. The improved electrochemical stability of the sulfide solid electrolyte against metallic lithium is attributed to the formation of Nb and Li2O at the interface, which can induce uniform Li deposition and prevent further side reaction. The all-solid-state Li/Li2S batteries based on this electrolyte exhibit remarkably enhanced cycling stability and rate performance.

Spectroscopic approach for the interaction of carbon nanoparticles with cytochrome c and BY-2 cells: Protein structure and mitochondrial function.

In this study, we employed multiple spectroscopic methods to analyze the effects of carbon nanoparticles (CNPs) on structure of cytochrome c (Cyt c) and mitochondrial function in plant cells. The tertiary structures of aromatic amino acid in Cyt c were not changed after addition of CNPs. Cyt c was found to be absorbed on the surfaces of CNPs in a non-linear manner and only bound Cyt c can be reduced. In addition, the binding of Cyt c was found to increase the diameter of CNPs at lower concentrations. The redox potential of Cyt c was almost not affected after treatment with CNPs. There were no obvious differences in cellular ATP after exposure to CNPs, and the mitochondrial membrane potential (MMP) was significantly decreased once the CNPs concentration exceeded 31.25 µg/mL. The levels of reactive oxygen species (ROS) also were increased in BY-2 cells. Taken together, these findings provide basis for the interactions between CNPs and Cyt c, as well as the effect of CNPs treatment on the mitochondria function in plant cells.

Highly hydrophilic carbon nanoparticles: uptake mechanism by mammalian and plant cells.

As one of the carbon based materials, the potential application of carbon nanoparticles (CNPs) has emerged in the promotion of plant growth. However, knowledge on the biological mechanism of how the CNPs interact with plant cells is limited. In this study, nanostructures of CNPs were examined. The particles exhibited particulate morphology and their size distribution was in the range of 18 to 70 nm, with an average size of 30 nm. Hydrophilic groups of COOH and OH were present on the surface of CNPs, and CNPs showed the common feature of graphitic sp2 hybridization carbons. The CNPs were determined to be biocompatible with these two cell lines, mammalian cells (A549 cells) and plant cells (BY-2 cells). The COOH groups on the surface of CNPs were functionalized via covalent binding with a fluorescent dye for improvement of the fluorescence. The fluorescent carbon nanoparticles (FCNPs) were found to cross the cell membrane and enter cells (A549 cells and BY-2 cells) in an energy-dependent manner. Subsequently, the mechanism of FCNPs interaction with the cell membrane was evaluated in the presence of inhibitors that specifically affect different endocytosis membrane proteins. The FCNPs mainly entered A549 cells through caveolin-mediated endocytosis and macropinocytosis, and clathrin-dependent endocytosis was also involved in the transportation of the FCNPs. Clathrin-independent endocytosis mediated in the internalization of FCNPs in BY-2 cells. The way FCNPs entering cells will provide a fundamental understanding of the influence of CNPs on cell membrane.

[Effects of potassium humate on ginger root growth and its active oxygen metabolism].

A pool-culture experiment was conducted to study the effects of potassium humate on the growth and active oxygen metabolism of ginger root. The results showed that applying potassium humate increased the root fresh mass and root vigor significantly, and promoted the root growth especially in later period. Potassium humate application obviously increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), decreased the content of MDA, and delayed the senescence of ginger root. After applying potassium humate, the soluble protein content in root was increased by 49.18%, 25.89% and 13.26%, and the yield was increased by 61.29%, 48.13% and 9.92%, respectively, compared with the treatments CK, same application rate of humic acid, and same application rate of potassium monoxide.