Carbon nanosol promotes plant growth and broad-spectrum resistance.

Carbon nanosol (CNS) is a carbon-based nanomaterial capable of promoting plant growth while the underlying mechanism involved in this process remains unknown. This study demonstrates that CNS promotes rice seedling growth under restricted concentrations. Macroelement transporter mutants were investigated to further investigate the CNS-mediated promotion of rice seedling growth. The genetic and physiological findings revealed that nitrate transporter 1.1B (NRT1.1B) and ammonium transporter 1 (AMT1) mutants inhibited the CNS-induced growth development of rice seedlings, whereas potassium transporter (AKT1) and phosphate transporter 8 (PT8) did not exhibit any inhibitory effects. Further investigations demonstrated the inhibition of CNS-mediated growth promotion via glutamine synthetase 1;1 (gs1;1) mutants. Additionally, the administration of CNS resulted in enhanced accumulation of chlorophyll in plants, and the promotion of CNS-induced growth was inhibited by yellow-green leaf 8 (YGL8) mutants and the chlorophyll biosynthetic gene divinyl reductase (DVR) mutants. According to these findings, the CNS promotes plant growth by stimulating chlorophyll biosynthesis. Furthermore, the presence of CNS enhanced the ability of rice to withstand blast, sheath blight (ShB), and bacterial blight. The nrt1.1b, amt1, dvr, and ygl8 mutants did not exhibit a broad spectrum effect. The positive regulation of broad-spectrum resistance in rice by GS1;1 suggests the requirement of N assimilation for CNS-mediated broad-spectrum resistance. In addition, an in vitro assay demonstrated that CNS inhibits the growth of pathogens responsible for blast, ShB, and bacterial blight, namely Magnaporthe oryzae, Rhizoctonia solani AG1-IA, and Xanthomonas oryzae pv. Oryzae, respectively. CNS application may also induce broad-spectrum resistance against bacterial and fungal pathogens, indicating that in addition to its antifungal and antibacterial properties, CNS application may also stimulate N assimilation. Collectively, the results indicate that CNS may be a potential nano-therapeutic agent for improved plant growth promotion while also providing broad-spectrum resistance.

Exploring Gas-Phase Chemical Reactions in NH3/B2H6 Systems for Chemical Vapor Deposition Using Reactive Molecular Dynamics.

Hexagonal boron nitride (hBN) has attracted significant attention as a two-dimensional (2D) material due to its unique structure and properties. In this paper, we investigated the gas-phase reactions between B2H6 and NH3 and the reaction pathways potentially leading to the synthesis of hBN by using ReaxFF-based reactive molecular dynamics (MD) simulations. From the hundreds of chemical reaction pathways observed in these MD simulations, we extracted a highly reduced chemical kinetic model to describe the gas-phase mixture evolution in chemical vapor deposition of hBN using B2H6 and NH3 as precursors. The intent is to integrate this chemical model into future computational fluid dynamics (CFD) simulations of actual hBN deposition testing and production reactors to provide enhanced insights for experimental synthesis processes and reactor optimization. The chemical model of this study will serve as a stepping stone for large-scale simulations.

Gibberellic acid signaling promotes resistance to saline-alkaline stress by increasing the uptake of ammonium in rice.

Gibberellic acid (GA) plays important roles in diverse biological processes in plants. However, its function in rice (Oryza sativa) resistance to saline-alkaline (SAK) stress is unclear. This study showed that SAK stimuli changed GA signaling gene expression levels. Genetic analyses using the mutants of key GA signaling regulators, Slender rice 1 (SLR1) and Dwarf 1(D1), demonstrated that SLR1 negatively, while D1 positively regulated the resistance of rice to SAK stress, suggesting that the GA signaling positively regulates the resistance of rice to SAK. Further analyses revealed that SLR1 interacted with and inhibited the transcription activation activity of IDD10 and bZIP23. Furthermore, IDD10 interacted with bZIP23 to activate Ammonium transporter 1;2 (AMT1;2), and slr1, IDD10 OX and bZIP23 OX accumulated more ammonium (NH4+), while idd10 and bzip23 accumulated less NH4+ than the wild-type (WT). In addition, the bzip23 mutant was more sensitive to SAK, while bZIP23 OX was less sensitive compared with the WT, suggesting that bZIP23 positively regulates the resistance of rice to SAK. These findings demonstrate that GA signaling promoted rice's SAK resistance by regulating NH4+ uptake through the SLR1-IDD10-bZIP23 pathway.

A new biphenanthrene with cytotoxic activity from Liparis nervosa (Thunb.) Lindl.

2,7,2'-Trihydroxy-3,4,4'7'-tetramethoxy-1,1'-biphenanthrene (1), a previously undescribed biphenanthrene, and five known phenanthrenes, i.e. 2,5-dihydroxy-4-methoxy-9,10-dihydroxyphenanthrene (2), 2,4-dihydroxy -7-methoxy-9,10-dihydroxyphenanthrene (3), 7-hydroxy-2-methoxy-phenanthrene-1,4-dione (4), 7-hydroxy-2-methoxy-9,10-dihydro-phenanthrene-1,4-dione (5), and 4,4',7,7'-tetrahydroxy-2,2'-dimethoxy-9,9',10,10'-tetrahydro-1,1'-biphenanthrene (6) were isolated from the whole plant (stems, leaves, roots and fruits) of Liparis nervosa (Thunb.) Lindl., which is a medicinal plant of the genus Liparis in the Orchidaceae family. The structures of isolates were identified using spectroscopic methods, including NMR and mass spectrometry. Additionally, the cytotoxic potency of all the isolates against human lung cancer A549 cell line was evaluated by an MTT assay. All the isolated compounds showed cytotoxic activities with IC50 values in the range of 10.20 ± 0.81 to 42.41 ± 2.34 µM. The obtained data highlight the importance of L. nervosa as a source of natural lead compounds for cancer therapy.

Single-cell analysis of human prepuce reveals dynamic changes in gene regulation and cellular communications.

BACKGROUND: The cellular and molecular dynamics of human prepuce are crucial for understanding its biological and physiological functions, as well as the prevention of related genital diseases. However, the cellular compositions and heterogeneity of human prepuce at single-cell resolution are still largely unknown. Here we systematically dissected the prepuce of children and adults based on the single-cell RNA-seq data of 90,770 qualified cells. RESULTS: We identified 15 prepuce cell subtypes, including fibroblast, smooth muscle cells, T/natural killer cells, macrophages, vascular endothelial cells, and dendritic cells. The proportions of these cell types varied among different individuals as well as between children and adults. Moreover, we detected cell-type-specific gene regulatory networks (GRNs), which could contribute to the unique functions of related cell types. The GRNs were also highly dynamic between the prepuce cells of children and adults. Our cell-cell communication network analysis among different cell types revealed a set of child-specific (e.g., CD96, EPO, IFN-1, and WNT signaling pathways) and adult-specific (e.g., BMP10, NEGR, ncWNT, and NPR1 signaling pathways) signaling pathways. The variations of GRNs and cellular communications could be closely associated with prepuce development in children and prepuce maintenance in adults. CONCLUSIONS: Collectively, we systematically analyzed the cellular variations and molecular changes of the human prepuce at single-cell resolution. Our results gained insights into the heterogeneity of prepuce cells and shed light on the underlying molecular mechanisms of prepuce development and maintenance.

ß-Glucanase Family Genes Promote Resistance to Sheath Blight in Rice by Inhibiting the Permeability of Plasmodesmata.

Rice sheath blight (ShB) caused by Rhizoctonia solani is one of the most serious diseases that threatens rice (Oryza sativa) production. However, the mechanisms of defense against ShB in rice remain largely unknown. In this study, we identified that the expression levels of ß-glucanase (OsBGL) family genes sensitively respond to infection by R. solani, and OsBGLs positively regulate rice resistance to ShB. In addition, OsBGL2 colocalized with AtPDCB1 at the plasmodesmata (PD) and limited the PD permeability. The level of callose accumulation in osbgls mutants and overexpressors was examined, and OsBGLs were found contribute to callose accumulation. Taken together, these data suggest that OsBGLs can regulate the deposition of callose at the PD to reduce its permeability to defend itself against ShB. Through the identification of these genes and the elucidation of their functions, this research fills the gap in the mechanism of PD permeability in rice ShB resistance.

bZIP23 interacts with NAC028 to modulate rice resistance to sheath blight disease.

Rice sheath blight disease (ShB) is a serious threat to rice production, and breeding ShB-resistance varieties is the most effective strategy for ShB control. However, the molecular mechanisms of rice resistance to ShB are largely unknown. In this study, the NAC transcription factor NAC028 was shown to be sensitive to ShB infection. ShB inoculation assays revealed that NAC028 is a positive regulator of ShB resistance. To elucidate the molecular basis of NAC028-mediated ShB resistance, another transcription factor (bZIP23) was identified as a NAC028-interacting protein. Results of the transcriptome and qRT-PCR analyses demonstrated that CAD8B, a key enzyme for lignin biosynthesis and ShB resistance, is regulated by both bZIP23 and NAC028. The combination of the yeast-one hybrid, ChIP-qPCR, and transactivation assays illustrated that both bZIP23 and NAC028 directly bind the CAD8B promoter and activate its expression. The transcriptional connection between bZIP23 and NAC028 was also investigated and the results of in vitro and in vivo assays demonstrated that NAC028 was one of the target genes of bZIP23, but not vice versa. The results presented here provide new insights into the molecular basis of ShB resistance and contribute to the potential targets for the ShB resistance breeding program.

Rhizoctonia solani transcriptional activator interacts with rice WRKY53 and grassy tiller 1 to activate SWEET transporters for nutrition.

INTRODUCTION: Rhizoctonia solani, the causative agent of the sheath blight disease (ShB), invades rice to obtain nutrients, especially sugars; however, the molecular mechanism via which R. solani hijacks sugars from rice remains unclear. OBJECTIVES: In this study, rice-R. solani interaction model was used to explore whether pathogen effector proteins affect plant sugar absorption during infection. METHODS: Yeast one-hybrid assay was used to identify Activator of SWEET2a (AOS2) from R. solani. Localization and invertase secretion assays showed that nuclear localization and secreted function of AOS2. Hexose transport assays verified the hexose transporter activity of SWEET2a and SWEET3a. Yeast two-hybrid assays, Bimolecular fluorescence complementation (BiFC) and transactivation assay were conducted to verify the AOS2-WRKY53-Grassy tiller 1 (GT1) transcriptional complex and its activation of SWEET2a and SWEET3a. Genetic analysis is used to detect the response of GT1, WRKY53, SWEET2a, and SWEET3a to ShB infestation. Also, the soluble sugar contents were measured in the mutants and overexpression plants before and after the inoculation of R. solani. RESULTS: The present study found that R. solani protein AOS2 activates rice SWEET2a and localized in the nucleus of tobacco cells and secreted in yeast. AOS2 interacts with rice transcription factor WRKY53 and GT1 to form a complex that activates the hexose transporter gene SWEET2a and SWEET3a and negatively regulate rice resistance to ShB. CONCLUSION: These data collectively suggest that AOS2 secreted by R. solani interacts with rice WRKY53 and GT1 to form a transcriptional complex that activates SWEETs to efflux sugars to apoplast; R. solani acquires more sugars and subsequently accelerates host invasion.

Red-light receptor phytochrome B inhibits BZR1-NAC028-CAD8B signaling to negatively regulate rice resistance to sheath blight.

Phytochrome (Phy)-regulated light signalling plays important roles in plant growth, development, and stress responses. However, its function in rice defence against sheath blight disease (ShB) remains unclear. Here, we found that PhyB mutation or shade treatment promoted rice resistance to ShB, while resistance was reduced by PhyB overexpression. Further analysis showed that PhyB interacts with phytochrome-interacting factor-like 15 (PIL15), brassinazole resistant 1 (BZR1), and vascular plant one-zinc-finger 2 (VOZ2). Plants overexpressing PIL15 were more susceptible to ShB in contrast to bzr1-D-overexpressing plants compared with the wild-type, suggesting that PhyB may inhibit BZR1 to negatively regulate rice resistance to ShB. Although BZR1 is known to regulate brassinosteroid (BR) signalling, the observation that BR signalling negatively regulated resistance to ShB indicated an independent role for BZR1 in controlling rice resistance. It was also found that the BZR1 ligand NAC028 positively regulated resistance to ShB. RNA sequencing showed that cinnamyl alcohol dehydrogenase 8B (CAD8B), involved in lignin biosynthesis was upregulated in both bzr1-D- and NAC028-overexpressing plants compared with the wild-type. Yeast-one hybrid, ChIP, and transactivation assays demonstrated that BZR1 and NAC028 activate CAD8B directly. Taken together, the analyses demonstrated that PhyB-mediated light signalling inhibits the BZR1-NAC028-CAD8B pathway to regulate rice resistance to ShB.

Mutation of phytochrome B promotes resistance to sheath blight and saline-alkaline stress via increasing ammonium uptake in rice.

Phytochrome B (PhyB), a red-light receptor, plays important roles in diverse biological processes in plants; however, its function in NH4 + uptake and stress responses of plants is unclear. Here, we observed that mutation in indeterminate domain 10 (IDD10), which encodes a key transcription factor in NH4 + signaling, led to NH4 + -sensitive root growth in light but not in the dark. Genetic combinations of idd10 and phy mutants demonstrated that phyB, but not phyA or phyC, suppressed NH4 + -sensitive root growth of idd10. PhyB mutants and PhyB overexpressors (PhyB OXs) accumulated more and less NH4 + , respectively, compared with wild-type plants. Real time quantitative polymerase chain reaction (RT-qPCR) revealed that PhyB negatively regulated NH4 + -mediated induction of Ammonium transporter 1;2 (AMT1;2). AMT1 RNAi plants with suppressed AMT1;1, AMT1;2, and AMT1;3 expression exhibited shorter primary roots under NH4 + conditions. This suggested that NH4 + uptake might be positively associated with root growth. Further, PhyB interacted with and inhibited IDD10 and brassinazole-resistant 1 (BZR1). IDD10 interacted with BZR1 to activate AMT1;2. NH4 + uptake is known to promote resistance of rice (Oryza sativa) to sheath blight (ShB) and saline-alkaline stress. Inoculation of Rhizoctonia solani demonstrated that PhyB and IDD10 negatively regulated and AMT1 and BZR1 positively regulated resistance of rice to ShB. In addition, PhyB negatively regulated and IDD10 and AMT1 positively regulated resistance of rice to saline-alkaline stress. This suggested that PhyB-IDD10-AMT1;2 signaling regulates the saline-alkaline response, whereas the PhyB-BZR1-AMT1;2 pathway modulates ShB resistance. Collectively, these data prove that mutation in the PhyB gene enhances the resistance of rice to ShB and saline-alkaline stress by increasing NH4 + uptake.

Comparative transcriptome analysis reveals that ATP synthases regulate Fusarium oxysporum virulence by modulating sugar transporter gene expressions in tobacco.

Fusarium oxysporum is a main causative agent of tobacco root rot, severely affecting tobacco growth. Here, 200 F. oxysporum strains were isolated and examined for their virulence toward tobacco plants. These strains were divided into disease class 1-3 (weak virulence), 4-6 (moderate virulence), and 7-9 (strong virulence). To understand the virulence mechanism of F. oxysporum, a comparative transcriptome study was performed using weak, moderate, and strong virulence-inducing strains. The results showed that expression levels of 1,678 tobacco genes were positively correlated with virulence levels, while expression levels of 3,558 genes were negatively associated with virulence levels. Interestingly, the expression levels of ATP synthase genes were positively correlated with F. oxysporum virulence. To verify whether ATP synthase gene expression is associated with F. oxysporum virulence, 5 strains each of strong, moderate, and weak virulence-inducing strains were tested using qRT-PCR. The results confirmed that ATP synthase gene expression is positively correlated with virulence levels. Knock-out mutants of ATP synthase genes resulted in a relatively weak virulence compared to wild-type as well as the inhibition of F. oxysporum-mediated suppression of NtSUC4, NtSTP12, NtHEX6, and NtSWEET, suggesting that ATP synthase activity is also associated with the virulence. Taken together, our analyses show that ATP synthases are key genes for the regulation of F. oxysporum virulence and provide important information for understanding the virulence mechanism of F. oxysporum in tobacco root rot.

Understanding Ozone Transport and Deposition within Indoor Surface Boundary Layers.

Ozone-initiated oxidation reactions on indoor surfaces meaningfully alter the chemical composition of indoor air and human exposure to air toxins. Ozone mass transport within the indoor surface boundary layer plays a key role in ozone-surface reaction kinetics. However, limited information is available on detailed ozone transport dynamics near realistic, irregular indoor surfaces. This paper presents a research framework to study the underlying mechanisms of ozone reactions with realistic indoor surfaces based on microscope scanning of surface material and detailed Computational Fluid Dynamics (CFD) simulation. The study results show that indoor surface topography can meaningfully affect ozone mass transport within a surface boundary layer, thereby modulating near-surface ozone concentration gradient and surface uptake. The results also reveal that the effective indoor surface area available for ozone reaction varies with indoor air speed and turbulent air mixing within the boundary layer. The detailed dynamic behaviors of ozone reactions with realistic indoor surfaces provide insights into the implications of pollutant-surface interactions on indoor chemistry and air quality.

Ac/Ds-Induced Receptor-like Kinase Genes Deletion Provides Broad-Spectrum Resistance to Bacterial Blight in Rice.

Rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) seriously affects rice yield production. The discovery and application of broad-spectrum resistance genes are of great advance for disease resistance breeding. Previously, we identified that multiple receptor-like kinase (RLK) family gene deletions induced by the Ac/Ds system resulted in a lesion mimic symptom. In this study, the mutant #29 showed that this lesion mimic symptom was isolated. Further analysis identified that four RLK genes (RLK19-22) were deleted in the #29 mutant. The #29 mutant exhibited broad-spectrum resistance to Xoo and subsequent analyses identified that pathogenesis-related genes PR1a, PBZ1, and cellular H2O2 levels were significantly induced in the mutant compared to wild-type plants. A genetic analysis revealed that reconstruction of RLK20, RLK21, or RLK22 rescued the lesion mimic symptom of the #29 mutant, indicating that these three RLKs are responsible for broad-spectrum resistance in rice. Further yeast two hybrid and bimolecular fluorescence complementation assays demonstrated that RLK20 interacts with RBOHB, which is a ROS producer in plants. Compared to wild-type plants, the #29 mutant was more, while #29/RLK20ox was less, susceptible to MV (methyl-viologen), an ROS inducer. Co-expression of RLK20 and RBOHB reduced RBOHB-promoted H2O2 accumulation in the cells. Taken together, our research indicated that the RLKs may inhibit RBOHB activity to negatively regulate rice resistance to Xoo. These results provide the theoretical basis and valuable information about the target genes necessary for the successful breeding of rice cultivars resistant to bacterial blight.

From Functional Characterization to the Application of SWEET Sugar Transporters in Plant Resistance Breeding.

The occurrence of plant diseases severely affects the quality and quantity of plant production. Plants adapt to the constant invasion of pathogens and gradually form a series of defense mechanisms, such as pathogen-associated molecular pattern-triggered immunity and microbial effector-triggered immunity. Moreover, many pathogens have evolved to inhibit the immune defense system and acquire plant nutrients as a result of their coevolution with plants. The sugars will eventually be exported transporters (SWEETs) are a novel family of sugar transporters that function as uniporters. They provide a channel for pathogens, including bacteria, fungi, and viruses, to hijack sugar from the host. In this review, we summarize the functions of SWEETs in nectar secretion, grain loading, senescence, and long-distance transport. We also focus on the interaction between the SWEET genes and pathogens. In addition, we provide insight into the potential application of SWEET genes to enhance disease resistance through the use of genome editing tools. The summary and perspective of this review will deepen our understanding of the role of SWEETs during the process of pathogen infection and provide insights into resistance breeding.

In situ temperature measurements in sooting methane/air flames using synchrotron x-ray fluorescence of seeded krypton atoms.

Synchrotron x-ray fluorescence has been used to measure temperatures in optically dense gases where traditional methods would fail. These data provide a benchmark for stringent tests of computational fluid dynamics models for complex systems where physical and chemical processes are intimately linked. The experiments measured krypton number densities in a sooting, atmospheric pressure, nonpremixed coflow flame that is widely used in combustion research. The experiments not only form targets for the models, but the simulations also identify potential sources of uncertainties in the measurements, allowing for future improvements.

Ammonium transporter 1 increases rice resistance to sheath blight by promoting nitrogen assimilation and ethylene signalling.

Sheath blight (ShB) significantly threatens rice yield production. However, the underlying mechanism of ShB defence in rice remains largely unknown. Here, we identified a highly ShB-susceptible mutant Ds-m which contained a mutation at the ammonium transporter 1;1 (AMT1;1) D358 N. AMT1;1 D358 N interacts with AMT1;1, AMT1;2 and AMT1;3 to inhibit the ammonium transport activity. The AMT1 RNAi was more susceptible and similar to the AMT1;1 D358 N mutant; however, plants with higher NH4+ uptake activity were less susceptible to ShB. Glutamine synthetase 1;1 (GS1;1) mutant gs1;1 and overexpressors (GS1;1 OXs) were more and less susceptible to ShB respectively. Furthermore, AMT1;1 overexpressor (AMT1;1 OX)/gs1;1 and gs1;1 exhibited a similar response to ShB, suggesting that ammonium assimilation rather than accumulation controls the ShB defence. Genetic and physiological assays further demonstrated that plants with higher amino acid or chlorophyll content promoted rice resistance to ShB. Interestingly, the expression of ethylene-related genes was higher in AMT1;1 OX and lower in RNAi mutants than in wild-type. Also, ethylene signalling positively regulated rice resistance to ShB and NH4+ uptake, suggesting that ethylene signalling acts downstream of AMT and also NH4+ uptake is under feedback control. Taken together, our data demonstrated that the AMT1 promotes rice resistance to ShB via the regulation of diverse metabolic and signalling pathways.

Non-radical mechanism and toxicity analysis of ß-cyclodextrin functionalized biochar catalyzing the degradation of bisphenol A and its analogs by peroxydisulfate.

Bisphenols (BPs) are distributed in worldwide as typical environmental hormones, which potentially harm the ecological environment and human health. In this study, four BPs, i.e., bisphenol A, bisphenol F, bisphenol S, and bisphenol AF, were used as prototypes to identify the intrinsic differences in degradation mechanisms correlated with the molecular structures in peroxydisulfate (PDS)-based advanced oxidation processes (AOPs). Electron transfer was the main way of modified biochar to trigger the heterogenous catalysis of PDS, which can cause the degradation of BPs. Phenolic hydroxyl groups on bisphenol pollutants were considered as possible active sites, and the existence of substituents was the main reason for the differentiation in the degradation efficiency of various bisphenols. Results of ecotoxicity prediction showed that most intermediates produced by the degradation of BPs in the ß-SB/PDS system, which was dominated by the electron transfer pathway, had a lower toxicity than the parent molecules, while the toxicity of several ring cleavage intermediates was higher. This study presents a simple modification scheme for the conversion of biochar into functional catalysts and provides insights into the mechanism of heterogeneous catalytic degradation mediated by modified biochar as well as the degradation differences of bisphenol pollutants and their potential ecotoxicity.