During development, cell fate determination hinges on the dynamic activities of multiple transcription factors (TFs), but how the activities of individual TFs contribute to developmental diversity remains incompletely understood. Here, we report that BZU2/ZmMUTE is responsible for the functional and spatial heterogeneity of the four-celled stomatal complexes in maize (Zea mays), in part through its liquid-liquid phase separation (LLPS) property. Genotypic and single-cell RNA-seq analyses confirmed previous findings that ZmMUTE is associated with lineage-specific gene expression during stomatal development, while providing additional resolution of cell-type-specific transcriptional programs. The intrinsically disordered region 4 (IDR4) promotes the formation of ZmMUTE condensates, which can recruit the ZmMUTE partner ZmSCRM and associate with transcriptionally active sites. These condensates are associated with enhanced DNA binding and target gene activation, potentially influencing the development of guard cells and subsidiary cells. IDR4 is also sufficient for conferring cell-to-cell mobility to AtMUTE, highlighting its conserved role in facilitating intercellular movement. Taken together, the dynamic behavior of ZmMUTE, owing to its condensational properties, appears to orchestrate cell-type-specific regulation, thereby enabling the emergence of the unique four-celled stomatal morphology.

Spike length (SL) is a crucial factor influencing yield in wheat (Triticum aestivum L.). In this study, a recombinant inbred line (RIL) population derived from the cross between Guixie 3 and Avocet S was utilized for genetic mapping of quantitative trait loci (QTL) controlling spike length. The results identified a total of 15 QTL distributed on chromosomes 2A, 2D, 4B, 5A, 5D, 6 A, 6B, and 6D. Among these, QSL.gaas-4B was mapped to a physical interval of 25.84–29.20 Mb (3.35 Mb) on chromosome 4B (Reference genome: Chinese Spring v2.1), which was detected across two environments (2023HB, 2024HB) and explained 18.09

RNA G-quadruplexes (G4s) formed at the 5'-end of the RNA component of human telomerase (hTR) are known to directly affect telomerase activity. However, the unfolding kinetics of hTR1-18 G4s at physiological K+ conditions have not been analyzed due to their extremely high thermal stability (Tm > 80°C). Here, we overcome this challenge by measuring the unfolding rates of hTR1-18 RNA G4s using single-molecule magnetic tweezers and bulk RNase digestion assays. We found that hTR1-18 RNA G4s exhibited exceptionally high mechanical stability and slow unfolding rates (10-7 s-1) in physiologically relevant 100 mm KCl buffer. Furthermore, we directly determined the digestion rate (kdig = 1.2 × 10-5 s-1) of hTR1-18 RNA G4s in the presence of a high concentration of 1 U/µL RNase T1, which suggests that the RNase T1 can digest folded RNA G4 structure. Importantly, G4-specific helicase DHX36 efficiently overcame this kinetic barrier, significantly reduced the fraction of folded hTR1-18 G4s from 99% to 16%, and rendered them susceptible to RNase degradation. These results illuminate the remarkable kinetic stability of RNA G4s and highlight the crucial role of helicase-dependent unfolding in controlling the persistence of RNA G4s in cells.

DNA:RNA hybrid G-quadruplexes (hG4s) are intermolecular G4 structures composed of guanine (G)-rich DNA and RNA strands. These structures play crucial regulatory roles in transcription and telomere stability. However, the absence of methods to produce uniform hG4s has limited systematic studies on their stability and unwinding. In this study, using human telomeric sequences as a model, we developed a PC (photocleavable)-linker-induced cleavage approach to generate hG4s with varying compositions and assessed their relative stability, revealing that hG4 stability increases with higher RNA content. We also showed that various G4-binding proteins recognize and bind to hG4 structures, with G4P exhibiting the highest affinity and effectively stabilizing hG4s. Additionally, the helicases Pif1 and RHAU were confirmed to efficiently unwind hG4 structures. Finally, we validated the roles of stabilizing and unwinding proteins in a transcription system. This study establishes a framework for investigating the stability and unwinding of hG4s and provides insights into modulating hG4 structures to regulate cellular processes.

Both DNA methylation and homologous recombination (HR) are extensively studied. In bacteria, Dam methylation is the most studied DNA modification, while RecA-mediated HR is a primary mechanism to repair DNA damages including double-stranded breaks, single-stranded gaps, and stalled replication forks. While HR regulation by proteins is extensively studied, whether methylation of DNA itself directly affects the functions of RecA and HR remains unclear. Mainly by single-molecule experiments, we report that Dam methylation of single-stranded DNA (ssDNA) promotes RecA assembly, partially by reducing the effective charge of ssDNA under counterion screening. Furthermore, Dam methylation of double-stranded DNA promotes homologous pairing, joint molecule growth, and strand exchange. In cellular experiments, dam deletion impairs HR, whereas hypermethylation of the adenines in the genome enhances HR in P1 transduction assays and DNA-damage sensitivity tests without significantly upregulated HR-related genes. In addition, the preference of RecA for Dam-methylated DNA in RecA assembly and homologous pairing is conserved across divergent species covering a gram-negative bacterium Klebsiella pneumoniae, a gram-positive bacterium Bacillus subtilis, and a flowering plant Arabidopsis thaliana. Dam methylation of ssDNA increases the ATPase activity of molecular motors such as RecQ helicase that containing RecA-like domains. These findings reveal effects of DNA methylation and mechanisms regulating RecA-mediated HR and molecular motors.

[This corrects the article DOI: 10.3389/fpls.2025.1556379.].

Hybrid chiral nanostructures hold great promise for next-generation photonic, catalytic, and biomedical technologies. However, the construction of hybrid chiral nanoparticles (NPs) with tunable chiroptical activity, high anisotropy factor (g-factor), and broad application potential remains a considerable challenge. Here, we report a chiral plasmon-dielectric coupling strategy to construct helicoid Au core-TiO2 shell nanostructures (GNH@TiO2) with enhanced and tunable chiroptical activity. By precisely controlling the TiO2 shell thickness, the optical activity profiles of the hybrid nanostructures are effectively extended to the near-infrared region with an enhanced g-factor up to 0.14. Systematic analysis indicates that the shell-dependent g-factors of GNH@TiO2 hybrids are closely associated with the chiral configuration of the hybrid structure induced by the coating of TiO2, as well as the electron transfer dynamics between GNH and TiO2. Moreover, the chiral GNH@TiO2 with a high g-factor exhibits asymmetric color modulation capability. Our findings provide a successful platform for engineering chiral hybrid nanostructures with tunable optical activities and mechanistic insights into the chiral plasmon-semiconductor interactions.

Introduction: Decaploid Camellia hainanica is a new tea oil Camellia species discovered in recent years that is unique to Hainan. This species has high nutritional and medicinal value and shows strong adaptability in the growth process. Mitochondria play an important role in plant cells and have an independent genetic system. Therefore, assembling and annotating the mitochondrial genome function of decaploid C. hainanica is of great significance. Methods: This study successfully assembled the mitochondrial genome of decaploid C. hainanica and comprehensively annotated its functional genes using the Nanopore sequencing platform. Results: Results showed that the mitochondrial genome is 902,617 bp in length, with a typical circular structure and a guanine-cytosine content of 45.79%. The genome encodes 64 protein-coding genes and contains a total of 76 genes, including 40 mRNA, 32 tRNA, 3 rRNA, and 1 pseudogene. Tetranucleotide repeats accounted for 38.60% of the simple sequence repeats. Only two genes, atp6 and sdh4, had a Ka/Ks ratio <1, whereas the Pi value of the sdh3 gene had a maximum of 0.00374 in these regions, suggesting that the sdh3 gene can be used as a molecular marker for the analysis of the mitochondrial genome of C. hainanica. From the relative synonymous codon usage (RSCU) analysis, 29 codons had RSCU values >1, 27 of which (93%) ended in A or U, indicating a bias for A/U endings is present in C. hainanica. During RNA editing, 48.24% (260 loci) of amino acids were changed from hydrophilic to hydryophobic, resulting in an increase in the hydrophobicity of the protein. Comparative analysis identified 34 homologous fragments between the mitochondrial and chloroplast genomes, with the longest fragment being 9,572 bp in length. Phylogenetic analysis of the genomes showed that the Hainanese and Vietnamese varieties of tea oil Camellia are sister species. Discussion: Results confirmed that the mitochondrial genomes of Hainanese and Vietnamese tea oil Camellia underwent gene rearrangement. Results also provided key data support for the utilization and conservation of tea oil germplasm resources and the breeding of varieties and are of great significance for promoting genetic evolution research, genetic breeding, and identification of tea oil Camellia.

Monovalent salts are generally believed to stabilize DNA duplex by weakening inter-strand electrostatic repulsion. Unexpectedly, our force-induced hairpin unzipping experiments and thermal melting experiments show that LiCl, NaCl, KCl, RbCl, and CsCl at concentrations beyond ~1 M destabilize DNA, RNA, and RNA-DNA duplexes. The two types of experiments yield different changes in free energy during melting, while the results that high concentration monovalent salts destabilize duplexes are common. The effects of these monovalent ions are similar but also have noticeable differences. From 1 M to 4 M, DNA duplex is destabilized by about 0.3 kBT/bp and the melting temperature decreases by about 10 oC. Our all-atom simulations reveal this effect is caused by overcharging, where excessive ion absorption inverts the effective DNA charge from negative to positive. Furthermore, our coarse-grained simulations obtain a phase diagram that indicates whether DNA overcharging occurs at a given cation valence and concentration. These findings challenge the traditional belief that DNA overcharging occurs only with multivalent ions and have significant implications for polyelectrolyte theory, DNA nanomaterials, DNA nanotechnology, and DNA biophysics. Experiments and simulations suggest monovalent salts destabilize DNA/RNA because of overcharging. These findings challenge views that overcharging requires multivalent ions, with implications for nanomaterials, nanotechnology, and biophysics.

BACKGROUND:The development of highly efficient and environmentally friendly plant virus inhibitors with novel structures mostly depends on the discovery of new targets. G-quadruplexes are non-classical high-level structures that are formed by guanine-rich nucleic acid sequences, which have significant biological functions. Small molecules that target the G-quadruplexes in the genomes of animal viruses have been shown to inhibit viral proliferation. However, the structure and function of the G-quadruplex in the plant virus genome have rarely been reported. Investigating the function of plant virus G-quadruplexes facilitates the discovery of new targets for screening viral inhibitors. RESULTS:In this study, we found that the 3'-end untranslated regions (3'UTRs) of cucumber mosaic virus (CMV) 1a, 2b, and CP genes all contain a putative G-quadruplex sequence (PQS) composed of the same base sequence, which was identified to fold into a G-quadruplex structure (CMV-3'UTR-PQS). In comparison to other G-quadruplex ligands, BRACO-19 exhibited the strongest binding affinity for the CMV-3'UTR-PQS. Further studies revealed BRACO-19 increased the ability of CMV-3'UTR-PQS to inhibit the expression of gene and exhibited an excellent anti-CMV activity. Moreover, BRACO-19 was found to induce the formation of intermolecular G-quadruplex structure from intramolecular G-quadruplex in CMV-3'UTR-PQS, and shifted the balance of the conformational ensemble of CMV-3'UTR-PQS in the direction of the compact conformation. CONCLUSION:This study suggested that CMV-3'UTR-PQS can be used as a target for screening viral inhibitors and provided new strategies for CMV prevention and control. © 2025 Society of Chemical Industry.

Limited by the activity-selectivity trade-off relationship, the electrochemical activation of small molecules (like O2, N2, and CO2) rapidly diminishes Faradaic efficiencies with elevated current densities (particularly at ampere levels). Nevertheless, some catalysts can circumvent this restriction in a two-electron oxygen reduction reaction (2e- ORR), a sustainable pathway for activating O2 to hydrogen peroxide (H2O2). Here we report 2e- ORR expedited in a fluorine-bridged copper metal-organic framework catalyst, arising from the water spillover effect. Through operando spectroscopies, kinetic and theoretical characterizations, it demonstrates that under neutral conditions, water spillover plays a dual role in accelerating water dissociation and stabilizing the key *OOH intermediate. Benefiting from water spillover, the catalyst can expedite 2e- ORR in the current density range of 0.1-2.0 A cm-2 with both high Faradaic efficiencies (99-84.9%) and H2O2 yield rates (63.17-1082.26 mg h-1 cm-2). Further, the feasibility of the present system has been demonstrated by scaling up to a unit module cell of 25 cm2, in combination with techno-economics simulations showing H2O2 production cost strongly dependent on current densities, giving the lowest H2O2 price of $0.50 kg-1 at 2.0 A cm-2. This work is expected to provide an additional dimension to leverage systems independent oftraditional rules.

Fusarium head blight (FHB) is a global detrimental disease affecting wheat production. While Guixie 3 shows strong resistance to FHB, its resistance mechanism is not well understood. Hence, this study aims to elucidate the genetic basis of disease resistance in Guixie 3 and identify new genetic resources for FHB resistance in wheat. The study used an F2:7 recombinant inbred line population developed by crossing Avocet S with Guixie 3. FHB resistance was phenotypically evaluated across 2 years and two locations (i.e., four environments) after single-floret inoculation, and it was genetically mapped using the wheat 55 K single-nucleotide polymorphism array. A total of 15 quantitative trait loci (QTLs) for FHB resistance were detected on chromosomes 1D (2), 2A (2), 2B (3), 2D.1 (2), 3B (1), 4A (1), 4B (1), 4D (1), 5A (1), and 5B.2 (1). Notably, a QTL on chromosome 2D.1, designated as Qfhb.gaas.2D.1–1, was consistently detected in two environments. This QTL spanned the interval AX-86163393 to AX-110072786, with a genetic interval of 45.12–46.51 cM and a physical interval of 35.68–37.04 Mb (1.36 Mb). It explained 14.07–33.00

Inorganic chiral hybrid nanostructures exhibit distinct chiroptical properties and functionalities compared to achiral systems and have attracted extensive attention due to their promising applications in photocatalytic, photoelectronic and information fields. However, significant challenges remain in constructing chiral hybrid nanostructures and exploring their chirality-dependent properties. Herein, we report chiral plasmonic metal-semiconductor core-shell nanostructures utilizing chiral gold nanohelicoid I (GNH I) as the core and titanium dioxide (TiO2) as the shell (denoted as GNH I@TiO2), and investigate their chirality-dependent photocatalytic properties. The results indicate the chiroptical activity of GNH I@TiO2 can be effectively regulated by varying the thickness of the TiO2 shell. The femtosecond transient absorption spectra (FTAS) study indicates that the effective coupling between the chiral core GNH I and the shell TiO2 not only promotes the chirality-dependent generation of hot carriers but importantly reduces the recombination of the generated carriers, leading to the chirality-dependent photocatalytic efficiencies. Consequently, the chiral GNH I@TiO2 hybrid nanostructures demonstrate chirality-dependent photocatalytic features when exposed to circularly polarized light (CPL). This work demonstrates a successful example of constructing chiral hybrid nanomaterials to enhance chiral light-matter interactions and facilitate their applications as potential chiroptical devices.

Water transportation to developing tissues relies on the structure and function of plant xylem cells. Plant microtubules govern the direction of cellulose microfibrils and guide secondary cell wall formation and morphogenesis. However, the relevance of microtubule-determined xylem wall thickening patterns in plant hydraulic conductivity remains unclear. In the present study, we identified a maize (Zea mays) semi-dominant mutant, designated drought-overly-sensitive1 (ZmDos1), the upper leaves of which wilted even when exposed to well-watered conditions during growth; the wilting phenotype was aggravated by increased temperatures and decreased humidity. Protoxylem vessels in the stem and leaves of the mutant showed altered thickening patterns of the secondary cell wall (from annular to spiral), decreased inner diameters, and limited water transport efficiency. The causal mutation for this phenotype was found to be a G-to-A mutation in the maize gene α-tubulin4, resulting in a single amino acid substitution at position 196 (E196K). Ectopic expression of the mutant α-tubulin4 in Arabidopsis (Arabidopsis thaliana) changed the orientation of microtubule arrays, suggesting a determinant role of this gene in microtubule assembly and secondary cell wall thickening. Our findings suggest that the spiral wall thickenings triggered by the α-tubulin mutation are stretched during organ elongation, causing a smaller inner diameter of the protoxylem vessels and affecting water transport in maize. This study underscores the importance of tubulin-mediated protoxylem wall thickening in regulating plant hydraulics, improves our understanding of the relationships between protoxylem structural features and functions, and offers candidate genes for the genetic enhancement of maize.

Arabidopsis (Arabidopsis thaliana) H+-ATPase1 (AHA1), a plasma membrane (PM)-localized H+-ATPase, plays a key role in plant alkali stress tolerance by pumping protons from the cytoplasm to the apoplast. However, its molecular dynamics are poorly understood. We report that many C2-domain ABA-related (CAR) protein family members interact with AHA1 in Arabidopsis. Single or double mutants of CAR1, CAR6, and CAR10 had no obvious phenotype of alkali stress tolerance, while their triple mutants showed significantly higher tolerance to this stress. The disruption of AHA1 largely compromised the increased alkali stress tolerance of the car1car6car10 mutant, revealing a key role of CARs in AHA1 regulation during the plant's response to a high alkali pH. Furthermore, variable-angle total internal reflection fluorescence microscopy was used to observe AHA1-mGFP5 in intact Arabidopsis seedlings, revealing the presence of heterogeneous diffusion coefficients and oligomerization states in the AHA1 spots. In the aha1 complementation lines, alkali stress curtailed the residence time of AHA1 at the PM and increased the diffusion coefficient and particle velocity of AHA1. In contrast, the absence of CAR proteins decreased the restriction of the dynamic behavior of AHA1. Our results suggest that CARs play a negative role in plant alkali stress tolerance by interacting with AHA1 and provide a perspective to investigate the regulatory mechanism of PM H+-ATPase activity at the single-particle level.

Plasma membrane (PM)-associated abscisic acid (ABA) signal transduction is an important component of ABA signaling. The C2-domain ABA-related (CAR) proteins have been reported to play a crucial role in recruiting ABA receptor PYR1/PYL/RCAR (PYLs) to the PM. However, the molecular details of the involvement of CAR proteins in membrane-delimited ABA signal transduction remain unclear. For instance, where this response process takes place and whether any additional members besides PYL are taking part in this signaling process. Here, the GUS-tagged materials for all Arabidopsis CAR members were used to comprehensively visualize the extensive expression patterns of the CAR family genes. Based on the representativeness of CAR1 in response to ABA, we determined to use it as a target to study the function of CAR proteins in PM-associated ABA signaling. Single-particle tracking showed that ABA affected the spatiotemporal dynamics of CAR1. The presence of ABA prolonged the dwell time of CAR1 on the membrane and showed faster lateral mobility. Surprisingly, we verified that CAR1 could directly recruit hypersensitive to ABA1 (HAB1) and SNF1-related protein kinase 2.2 (SnRK2.2) to the PM at both the bulk and single-molecule levels. Furthermore, PM localization of CAR1 was demonstrated to be related to membrane microdomains. Collectively, our study revealed that CARs recruited the three main components of ABA signaling to the PM to respond positively to ABA. This study deepens our understanding of ABA signal transduction.

Photodynamic Therapy (PDT) is recognized for its exceptional effectiveness as a promising cancer treatment method. However, it is noted that overexposure to the dosage and sunlight in traditional PDT can result in damage to healthy tissues, due to the low tumor selectivity of currently available photosensitizers (PSs). To address this challenge, we introduce herein a new strategy where the small molecule-targeted agent, erlotinib, is integrated into a boron dipyrromethene (BODIPY)-based PS to form conjugate 6 to enhance the precision of PDT. This conjugate demonstrates optical absorption, fluorescence emission, and singlet oxygen generation efficiency comparable to the reference compound 7, which lacks erlotinib. In vitro studies reveal that, after internalization, conjugate 6 predominantly accumulates in the lysosomes of HepG2 cells, exhibiting significant photocytotoxicity with an IC50 value of 3.01 µM. A distinct preference for HepG2 cells over HELF cells is observed with conjugate 6 but not with compound 7. In vivo experiments further confirm that conjugate 6 has a specific affinity for tumor tissues, and the combination treatment of conjugate 6 with laser illumination can effectively eradicate H22 tumors in mice with outstanding biosafety. This study presents a novel and potential PS for achieving precise PDT against cancer.

BACKGROUND:Maize is a major cereal crop world widely, however, the yield of maize is frequently limited by dehydration and even death of plants, which resulted from osmotic stress such as drought and salinity. Dissection of molecular mechanisms controlling stress tolerance will enable plant scientists and breeders to increase crops yield by manipulating key regulatory components. METHODS:The candidate OSR1 gene was identified by map-based cloning. The expression level of OSR1 was verified by qRT-PCR and digital PCR in WT and osr1 mutant. Electrophoretic mobility shift assay, transactivation activity assay, subcellular localization, transcriptome analysis and physiological characters measurements were conducted to analyze the function of OSR1 in osmotic stress resistance in maize. RESULTS:The osr1 mutant was significantly less sensitive to osmotic stress than the WT plants and displayed stronger water-holding capacity, and the OSR1 homologous mutant in Arabidopsis showed a phenotype similar with maize osr1 mutant. Differentially expressed genes (DEGs) were identified between WT and osr1 under osmotic stress by transcriptome analysis, the expression levels of many genes, such as LEA, auxin-related factors, PPR family members, and TPR family members, changed notably, which may primarily involve in osmotic stress or promote root development. CONCLUSIONS:OSR1 may serve as a negative regulatory factor in response to osmotic stress in maize. The present study sheds new light on the molecular mechanisms of osmotic stress in maize.

Photoluminescence (PL) metal nanoclusters (NCs) have attracted extensive attention due to their excellent physicochemical properties, good biocompatibility, and broad application prospects. However, developing water-soluble PL metal NCs with a high quantum yield (QY) and high stability for visual drug delivery remains a great challenge. Herein, we have synthesized ultrabright l-Arg-ATT-Au/Ag NCs (Au/Ag NCs) with a PL QY as high as 73% and excellent photostability by heteroatom doping and surface rigidization in aqueous solution. The as-prepared Au/Ag NCs can maintain a high QY of over 61% in a wide pH range and various ionic environments as well as a respectable resistance to photobleaching. The results from structure characterization and steady-state and time-resolved spectroscopic analysis reveal that Ag doping into Au NCs not only effectively modifies the electronic structure and photostability but also significantly regulates the interfacial dynamics of the excited states and enhances the PL QY of Au/Ag NCs. Studies in vitro indicate Au/Ag NCs have a high loading capacity and pH-triggered release ability of doxorubicin (DOX) that can be visualized from the quenching and recovery of PL intensity and lifetime. Imaging-guided experiments in cancer cells show that DOX of Au/Ag NCs-DOX agents can be efficiently delivered and released in the nucleus with preferential accumulation in the nucleolus, facilitating deep insight into the drug action sites and pharmacological mechanisms. Moreover, the evaluation of anticancer activity in vivo reveals an outstanding suppression rate of 90.2% for mice tumors. These findings demonstrate Au/Ag NCs to be a superior platform for bioimaging and visual drug delivery in biomedical applications.

Marine actinomycetes exhibit a high level of biodiversity and possess significant potential for the production of high-value secondary metabolites. During the course of investigation of marine actinobacteria from corals, two Saccharopolyspora strains, namely, HNM0983T and HNM0986T, were isolated from stony corals collected from the coastal area of Hainan Island. The 16S ribosomal RNA (rRNA) gene sequence analysis revealed that these two strains are putative novel taxa of the genus Saccharopolyspora. Whole-genome sequencing comparisons further confirmed the two strains as belonging to two novel Saccharopolyspora species, which can be distinguished phenotypically and chemically from their current closest phylogenetic relatives. Some genomic information of the genus Saccharopolyspora was compared for evaluating the production capacity of secondary metabolites. A total of 519 biosynthetic gene clusters (BGCs) from the genus Saccharopolyspora were used for analysis, and terpene BGCs were found to be widespread and most abundant in this genus. In addition, abundant novel BGCs in the genus Saccharopolyspora are not clustered with the known BGCs in the database, indicating that the metabolites of the genus Saccharopolyspora deserve further exploration. On the basis of these presented results, Saccharopolyspora montiporae sp. nov. (type strain = HNM0983T = CCTCC AA 2020014T = KCTC 49526T) and Saccharopolyspora galaxeae sp. nov. (type strain = HNM0986T = CCTCC AA 2020011T = KCTC 49524T) are proposed as the names for the new strains, respectively.