The Chemoreceptor Sensory Adaptation System Produces Coordinated Reversals of the Flagellar Motors on an Escherichia coli Cell.

In isotropic environments, an Escherichia coli cell exhibits coordinated rotational switching of its flagellar motors, produced by fluctuations in the intracellular concentration of phosphorylated CheY (CheY-P) emanating from chemoreceptor signaling arrays. In this study, we show that these CheY-P fluctuations arise through modifications of chemoreceptors by two sensory adaptation enzymes: the methyltransferase CheR and the methylesterase CheB. A cell containing CheR, CheB, and the serine chemoreceptor Tsr exhibited motor synchrony, whereas a cell lacking CheR and CheB or containing enzymatically inactive forms did not. Tsr variants with different combinations of methylation-mimicking Q residues at the adaptation sites also failed to show coordinated motor switching in cells lacking CheR and CheB. Cells containing CheR, CheB, and Tsr [NDND], a variant in which the adaptation site residues are not substrates for CheR or CheB modifications, also lacked motor synchrony. TsrΔNWETF, which lacks a C-terminal pentapeptide-binding site for CheR and CheB, and the ribose-galactose receptor Trg, which natively lacks this motif, failed to produce coordinated motor switching, despite the presence of CheR and CheB. However, addition of the NWETF sequence to Trg enabled Trg-NWETF to produce motor synchrony, as the sole receptor type in cells containing CheR and CheB. Finally, CheBc, the catalytic domain of CheB, supported motor coordination in combination with CheR and Tsr. These results indicate that the coordination of motor switching requires CheR/CheB-mediated changes in receptor modification state. We conclude that the opposing receptor substrate-site preferences of CheR and CheB produce spontaneous blinking of the chemoreceptor array's output activity. IMPORTANCE Under steady-state conditions with no external stimuli, an Escherichia coli cell coordinately switches the rotational direction of its flagellar motors. Here, we demonstrate that the CheR and CheB enzymes of the chemoreceptor sensory adaptation system mediate this coordination. Stochastic fluctuations in receptor adaptation states trigger changes in signal output from the receptor array, and this array blinking generates fluctuations in CheY-P concentration that coordinate directional switching of the flagellar motors. Thus, in the absence of chemoeffector gradients, the sensory adaptation system controls run-tumble swimming of the cell, its optimal foraging strategy.

Effects of Toxin-Antitoxin System HicAB on Biofilm Formation by Extraintestinal Pathogenic E. coli.

The type II toxin-antitoxin (T-A) HicAB system is abundant in several bacteria and archaea, such as Escherichia coli, Burkholderia Pseudomallei, Yersinia pestis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. This system engages in stress response, virulence, and bacterial persistence. This study showed that the biofilm-forming ability of the hicAB deletion mutant was significantly decreased to moderate ability compared to the extra-intestinal pathogenic Escherichia coli (ExPEC) parent strain and the complemented strain, which are strong biofilm producers. Congo red assay showed that the hicAB mutant maintained the ability to form curli fimbriae. Using RNA-seq and comparative real-time quantitative RT-PCR, we observed the difference in gene expression between the hicAB mutant and the parent strain, which was associated with biofilm formation. Our data indicate that the HicAB type II T-A system has a key role in biofilm formation by ExPEC, which may be associated with outer membrane protein (OMP) gene expression. Collectively, our results indicate that the hicAB type II T-A system is involved in ExPEC biofilm formation.

Pathogenicity and Whole Genome Sequence Analysis of a Pseudorabies Virus Strain FJ-2012 Isolated from Fujian, Southern China.

The outbreaks of pseudorabies have been frequently reported in Bartha-K61-vaccinated farms in China since 2011. To study the pathogenicity and evolution of the circulating pseudorabies viruses in Fujian Province, mainland China, we isolated and sequenced the whole genome of a wild-type pseudorabies virus strain named "FJ-2012." We then conducted a few downstream bioinformatics analyses including phylogenetic analysis and pathogenic analysis and used the virus to infect 6 pseudorabies virus-free piglets. FJ-2012-infected piglets developed symptoms like high body temperature and central nervous system disorders and had high mortality rate. In addition, we identified typical micropathological changes such as multiple gross lesions in infected piglets through pathological analysis and conclude that the FJ-2012 genome is significantly different from known pseudorabies viruses, in which insertions, deletions, and substitutions are observed in multiple immune and virulence genes. In summary, this study shed lights on the molecular basis of the prevalence and pathology of the pseudorabies virus strain FJ-2012. The genome of FJ-2012 could be used as a reference to study the evolution of pseudorabies viruses, which is critical to the vaccine development of new emerging pseudorabies viruses.

Load-sensitive coupling of proton translocation and torque generation in the bacterial flagellar motor.

The Salmonella flagellar motor consists of a rotor and about a dozen stator elements. Each stator element, consisting of MotA and MotB, acts as a proton channel to couple proton flow with torque generation. A highly conserved Asp33 residue of MotB is directly involved in the energy coupling mechanism, but it remains unknown how it carries out this function. Here, we show that the MotB(D33E) mutation dramatically alters motor performance in response to changes in external load. Rotation speeds of the MotA/B(D33E) and MotA(V35F)/B(D33E) motors were markedly slower than the wild-type motor and fluctuated considerably at low load but not at high load, whereas the rotation rate of the wild-type motor was stable at any load. At low load, pausing events were frequently observed in both mutant motors. The proton conductivities of these mutant stator channels in their 'unplugged' forms were only half of the conductivity of the wild-type channel. These results suggest that the D33E mutation induces a load-dependent inactivation of the MotA/B complex. We propose that the stator element is a load-sensitive proton channel that efficiently couples proton translocation with torque generation and that Asp33 of MotB is critical for this co-ordinated proton translocation.

Assembly and stoichiometry of FliF and FlhA in Salmonella flagellar basal body.

The bacterial flagellar export apparatus is required for the construction of the bacterial flagella beyond the cytoplasmic membrane. The membrane-embedded part of the export apparatus, which consists of FlhA, FlhB, FliO, FliP, FliQ and FliR, is located in the central pore of the MS ring formed by 26 copies of FliF. The C-terminal cytoplasmic domain of FlhA is located in the centre of the cavity within the C ring made of FliG, FliM and FliN. FlhA interacts with FliF, but its assembly mechanism remains unclear. Here, we fused yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP) to the C-termini of FliF and FlhA and investigated their subcellular localization by fluorescence microscopy. The punctate pattern of FliF-YFP localization required FliG but neither FliM, FliN, FlhA, FlhB, FliO, FliP, FliQ nor FliR. In contrast, FlhA-CFP localization required FliF, FliG, FliO, FliP, FliQ and FliR. The number of FlhA-YFP molecules associated with the MS ring was estimated to be about nine. We suggest that FlhA assembles into the export gate along with other membrane components during the MS ring complex formation in a co-ordinated manner.

G226, a new epipolythiodioxopiperazine derivative, triggers DNA damage and apoptosis in human cancer cells in vitro via ROS generation.

AIM: G226 is a novel derivative of epipolythiodioxopiperazines with potent inhibitory activity against cancer cells. Here, we sought to identify potential targets involved in the anti-cancer activity of G226. METHODS: Cell proliferation assay was conducted in a panel of 12 human cancer cell lines. The activities of topoisomerase I (Topo I) and Topo II were studied using supercoiled pBR322 DNA relaxation and kDNA decatenation assays. ROS production was assessed with probes DCFH-DA and H&E. Western blot analysis and flow cytometry were used to examine DNA damage, apoptosis and cell cycle changes. RESULTS: G226 displayed potent cytotoxicity in the 12 human cancer cell lines with a mean IC50 value of 92.7 nmol/L. This compound (1-100 µmol/L) selectively inhibited the activity of Topo II, and elevated the expression of phosphorylated-H2AX in a dose-dependent manner. In Topo II-deficient HL60/MX2 cells, however, G226-induced DNA damage, apoptosis and cytotoxicity were only partially reduced, suggesting that Topo II was not essential for the anti-tumor effects of G226. Furthermore, G226 (0.125-2 µmol/L) dose-dependently elevated the intracellular levels of H2O2 and in the cancer cells, and pretreatment with GSH, NAC or DTT not only blocked G226-induced intracellular accumulation of ROS, but also abrogated G226-mediated phosphorylation of H2AX, apoptosis and cytotoxicity. CONCLUSION: G226-mediated ROS production contributes to the anti-cancer activity of this compound.

G226, a novel epipolythiodioxopiperazine derivative, induces autophagy and caspase-dependent apoptosis in human breast cancer cells in vitro.

AIM: To investigate the effects of G226, a novel epipolythiodioxopiperazine derivative, on human breast cancer cells in vitro, and to explore its anticancer mechanisms. METHODS: A panel of human breast cancer cell lines (MDA-MB-231, MDA-MB-468, MCF-7, ZR-75-30, BT474, BT549, SK-BR-3, T47D and HBL100) was examined. Cell proliferation was measured using sulforhodamine B assay, and cell apoptosis was detected with flow cytometry and caspase activity assay. Western blotting, immunofluorescence and targeted gene knockdowns were used to study autophagy in the cells. RESULTS: G226 suppressed proliferation of the 9 breast cancer cell lines with a mean IC50 value of 48.5 nmol/L (the mean IC50 value of adriamycin, a reference compound, was 170.6 nmol/L). G226 induced dose-dependent apoptosis of MDA-MB-231 and MCF-7 cells, accompanied by markedly increased activities of caspase-8 and caspase-3/7, which were abolished by caspase inhibitors zVAD or zIETD. G226 also induced mitochondrial outer membrane permeabilization, resulted in the caspase-9 activation. Moreover, G226 dose-dependently enhanced the autophagy marker LC3-II and autophagy substrate p62 accumulation in the cells, which were co-localized with caspase-8. Silencing of p62 or LC3 partially diminished caspase-8 and subsequent caspase-3 activation. LC3 silencing partially reversed G226-induced apoptosis, but p62 silencing elicited a subtle effect on G226-induced apoptosis. CONCLUSION: The novel epipolythiodioxopiperazine derivative G226 exerts potent anticancer action against human breast cancer cells in vitro, via triggering autophagy and caspase-dependent apoptosis.

CheB localizes to polar receptor arrays during repellent adaptation.

Adaptation of the response to stimuli is a fundamental process for all organisms. Here, we show that the adaptation enzyme CheB methylesterase of Escherichia coli assembles to the ON state receptor array after exposure to the repellent l-isoleucine and dissociates from the array after adaptation is complete. The duration of increased CheB localization and the time of highly clockwise-biased flagellar rotation were similar and depended on the strength of the stimulus. The increase in CheB at the receptor array and the decrease in cytoplasmic CheB were both ~100 molecules, which represents 15 to 20% of the total cellular content of CheB. We confirmed that the main binding site for CheB in the ON state array is the P2 domain of phosphorylated CheA, with a second minor site being the carboxyl-terminal pentapeptide of the serine chemoreceptor. Thus, we have been able to quantify the regulation of the signal output of the receptor array by the intracellular dynamics of an adaptation enzyme.

Investigation of non-precious metal cathode catalysts for direct borohydride fuel cells.

Borohydride crossover in anion exchange membrane (AEM) based direct borohydride fuel cells (DBFCs) impairs their performance and induces cathode catalyst poisoning. This study evaluates three non-precious metal catalysts, namely LaMn0.5Co0.5O3 (LMCO) perovskite, MnCo2O4 (MCS) spinel, and Fe-N-C, for their application as cathode catalysts in DBFCs. The rotating disk electrode (RDE) testing shows significant borohydride tolerance of MCS. Moreover, MCS has exhibited exceptional stability in accelerated durability tests (ADTs), with a minimal reduction of 10 mV in half-wave potential. DFT calculations further reveal that these catalysts predominantly adsorb over , unlike commercial Pt/C which preferentially adsorbs . In DBFCs, MCS can deliver a peak power density of 1.5 W cm-2, and a 3% voltage loss after a 5 hours durability test. In contrast, LMCO and Fe-N-C have exhibited significantly lower peak power density and stability. The analysis of the TEM, XRD, and XPS results before and after the single-cell stability tests suggests that the diminished stability of LMCO and Fe-N-C catalysts is due to catalyst detachment from carbon supports, resulting from the nanoparticle aggregation during the high-temperature preparation process. Such findings suggest that MCS can effectively mitigate the fuel crossover challenge inherent in DBFCs, thus enhancing its viability for practical application.

Populational heterogeneity vs. temporal fluctuation in Escherichia coli flagellar motor switching.

The dynamic switching of the bacterial flagellar motor regulates cell motility in bacterial chemotaxis. It has been reported under physiological conditions that the switching bias of the flagellar motor undergoes large temporal fluctuations, which reflects noise propagating in the chemotactic signaling network. On the other hand, nongenetic heterogeneity is also observed in flagellar motor switching, as a large group of switching motors show different switching bias and frequency under the same physiological condition. In this work, we present simultaneous measurement of groups of Escherichia coli flagellar motor switching and compare them to long time recording of single switching motors. Consistent with previous studies, we observed temporal fluctuations in switching bias in long time recording experiments. However, the variability in switching bias at the populational level showed much higher volatility than its temporal fluctuation. These results suggested stable individuality in E. coli motor switching. We speculate that uneven expression of key regulatory proteins with amplification by the ultrasensitive response of the motor can account for the observed populational heterogeneity and temporal fluctuations.

'Living' PEGylation on gold nanoparticles to optimize cancer cell uptake by controlling targeting ligand and charge densities.

We report and demonstrate biomedical applications of a new technique--'living' PEGylation--that allows control of the density and composition of heterobifunctional PEG (HS-PEG-R; thiol-terminated poly(ethylene glycol)) on gold nanoparticles (AuNPs). We first establish 'living' PEGylation by incubating HS-PEG5000-COOH with AuNPs (∼20 nm) at increasing molar ratios from zero to 2000. This causes the hydrodynamic layer thickness to differentially increase up to 26 nm. The controlled, gradual increase in PEG-COOH density is revealed after centrifugation, based on the ability to re-suspend the pellet and increase the AuNP absorption. Using a fluorescamine-based assay we quantify differential HS-PEG5000-NH2 binding to AuNPs, revealing that it is highly efficient until AuNP saturation is reached. Furthermore, the zeta potential incrementally changes from -44.9 to +52.2 mV and becomes constant upon saturation. Using 'living' PEGylation we prepare AuNPs with different ratios of HS-PEG-RGD (RGD: Arg-Gly-Asp) and incubate them with U-87 MG (malignant glioblastoma) and non-target cells, demonstrating that targeting ligand density is critical to maximizing the efficiency of targeting of AuNPs to cancer cells. We also sequentially control the HS-PEG-R density to develop multifunctional nanoparticles, conjugating positively charged HS-PEG-NH2 at increasing ratios to AuNPs containing negatively charged HS-PEG-COOH to reduce uptake by macrophage cells. This ability to minimize non-specific binding/uptake by healthy cells could further improve targeted nanoparticle efficacy.

[Pharmacognostical study of Cyperus rotundus growing in Wen-River area].

OBJECTIVE: To study the macroscopic, microscopic identification and chemical components of Cyperus rotundus growing in Wen-River area. METHODS: The features of different parts of Cyperus rotundus were described by material morphology and microscopic identification, the chemical components of aerial part and rhizome of Cyperus rotundus were studied by chemical experiment and GC-MS analysis. RESULTS: Summarized the transverse section structure of rhizome, stem and leaf of Cyperus rotundus, the chemical components of aerial part and the components and relative content of volatile oil in rhizome were determined. CONCLUSION: This study provides reference for the drug identification and the daodi medicinal material exploitation of Cyperus rotundus.

High Prevalence, Genetic Diversity, and Recombination of Porcine Sapelovirus in Pig Farms in Fujian, Southern China.

Porcine sapelovirus (PSV) is a ubiquitous virus in farmed pigs that is associated with SMEDI syndrome, polioencephalomyelitis, and diarrhea. However, there are few reports on the prevalence and molecular characterization of PSV in Fujian Province, Southern China. In this study, the prevalence of PSV and a poetical combinative strain PSV2020 were characterized using real-time PCR, sequencing, and bioinformatics analysis. As a result, an overall sample prevalence of 30.8% was detected in 260 fecal samples, and a farm prevalence of 76.7% was observed in 30 Fujian pig farms, from 2020 to 2022. Noteably, a high rate of PSV was found in sucking pigs. Bioinformatics analysis showed that the full-length genome of PSV2020 was 7550 bp, and the genetic evolution of its ORF region was closest to the G1 subgroup, which was isolated from Asia and America; the similarity of nucleotides and amino acids to other PSVs was 59.5~88.7% and 51.7~97.0%, respectively. However, VP1 genetic evolution analysis showed a distinct phylogenetic topology from the ORF region; PSV2020 VP1 was closer to the DIAPD5469-10 strain isolated from Italy than strains isolated from Asia and America, which comprise the G1 subgroup based on the ORF region. Amino acid discrepancy analysis illustrated that the PSV2020 VP1 gene inserted twelve additional nucleotides, corresponding to four additional amino acids (STAE) at positions 898-902 AAs. Moreover, a potential recombination signal was observed in the 2A coding region, near the 3' end of VP1, owing to recombination analysis. Additionally, 3D genetic evolutionary analysis showed that all reference strains demonstrated, to some degree, regional conservation. These results suggested that PSV was highly prevalent in Fujian pig farms, and PSV2020, a PSV-1 genotype strain, showed gene diversity and recombination in evolutionary progress. This study also laid a scientific foundation for the investigation of PSV epidemiology, molecular genetic characteristics, and vaccine development.

Application of Decision Tree in PE Teaching Analysis and Management under the Background of Big Data.

With the continuous development of physical education reform, the defects and deficiencies of physical education teaching in colleges and universities are increasingly exposed. The reform of the original physical education teaching thought, education system, teaching mode, and method has achieved little. At present, the research on the prediction of physical education teaching achievements is mainly aimed at the prediction of athletes and physical education teaching achievements or the prediction of the past data of college students. This paper studies the physical education under the decision tree under the background of big data and constructs the physical education management system. When the number of tests reaches 40, the qualified rate of long-distance running is 65.2%, that of basketball is 68.1%, and that of volleyball is 68.2%. The quality of physical education teaching determines the lifeline of the development of school physical education teaching. In the process of collecting and selecting teaching materials, this paper enriches teaching materials and teaching reflection, cultivates one's own understanding, and improves the artistic appeal and creativity of teaching.

The Immune Efficacy of Inactivated Pseudorabies Vaccine Prepared from FJ-2012ΔgE/gI Strain.

An emerging pseudorabies virus (PRV) variant has been reported on Bartha-K61-vaccinated farms since 2011, causing great economic losses to China's swine-feeding industry. In this study, two vaccines, FJ-2012ΔgE/gI-GEL02 and FJ-2012ΔgE/gI-206VG, were administered to piglets for immune efficacy investigation. Humoral immunity response, clinical signs, survival rate, tissue viral load, and pathology were assessed in piglets. The results showed that both vaccines were effective against the PRV FJ-2012 challenge, the piglets all survived while developing a high level of gB-specific antibody and neutralizing antibody, the virus load in tissue was alleviated, and no clinical PR signs or pathological lesions were displayed. In the unimmunized challenged group, typical clinical signs of pseudorabies were observed, and the piglets all died at 7 days post-challenge. Compared with commercial vaccines, the Bartha-K61 vaccine group could not provide full protection, which might be due to a lower vaccine dose; the inactivated vaccine vPRV* group piglets survived, displaying mild clinical signs. The asterisk denotes inactivation. These results indicate that FJ-2012ΔgE/gI-GEL02 and FJ-2012ΔgE/gI-206VG were effective and could be promising vaccines to control or eradicate the new PRV epidemic in China.

Prebiotic-like cyclodextrin assisted silybin on NAFLD through restoring liver and gut homeostasis.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease with no currently approved treatment. The natural compound silybin (SLN) has versatile hepatoprotective efficacy with negligible adverse effects; however, poor absorption limits its clinical applications. Gut microbiota has been proposed to play a crucial role in the pathophysiology of NAFLD and targeted for disease control. Cyclodextrins, the cyclic oligosaccharides, were documented to have various health benefits with potential prebiotic properties. This study aimed to develop a silybin-2-hydroxypropyl-ß-cyclodextrin inclusion (SHßCD) to improve the therapeutic efficacy of SLN and elucidate the mechanisms of improvement. The results showed that SLN formed a 1:1 stoichiometric inclusion complex with HP-ß-CD. The solubility of SLN was increased by generating SHßCD, resulting in improved drug permeability and bioavailability. In high-fat diet (HFD)-fed hamsters, SHßCD modulated gut health by restoring the gut microbiota and intestinal integrity. SHßCD showed superior anti-lipid accumulation, antioxidant, and anti-inflammatory effects compared with SLN alone. Transcriptome analysis in the liver tissue implied that the improved inflammation and/or energy homeostasis was the potential mechanism. Therefore, SHßCD may be a promising alternative for the treatment of NAFLD, attributing to the dual functions of HßCD on drug absorption and gut microbial homeostasis.

Non-genetic individuality in Escherichia coli motor switching.

By analyzing 30 min, high-resolution recordings of single Escherichia coli flagellar motors in the physiological regime, we show that two main properties of motor switching-the mean clockwise and mean counter-clockwise interval durations-vary significantly. When we represent these quantities on a two-dimensional plot for several cells, the data do not fall on a one-dimensional curve, as expected with a single control parameter, but instead spread in two dimensions, pointing to motor individuality. The largest variations are in the mean counter-clockwise interval, and are attributable to variations in the concentration of the internal signaling molecule CheY-P. In contrast, variations in the mean clockwise interval are interpreted in terms of motor individuality. We argue that the sensitivity of the mean counter-clockwise interval to fluctuations in CheY-P is consistent with an optimal strategy of run and tumble. The concomittent variability in mean run length may allow populations of cells to better survive in rapidly changing environments by 'hedging their bets'.

Optical Properties of Thomson Scattering Diagnostics Lower Window Glass under Laser Irradiation.

Tokamak diagnostic window glass is an indispensable optical medium in fusion research. The transmittance of the device affects the optical performance and accuracy of the diagnostic system. Especially, the window glass serves as the entrance of the light source while performing the sealing function for the active diagnosis method represented by Thomson scattering diagnostics. In this work, we studied the influence of the laser irradiation and tokamak discharge on the EAST (Experimental Advanced Superconducting Tokamak) Thomson scattering diagnostic borosilicate glass window. Using X-ray photoelectron spectroscopy (XPS) and Raman scattering, we found that carbon-based impurities in the device aggravated the film damage due to laser irradiation, reducing the performance of the coating of the glass. Besides, the laser and the various rays of tokamak discharge generated many point defects in the glass, increasing the light absorption of the glass. These two factors caused the glass transmittance to drop significantly (from 99.99% to 77.62%). In addition, the long-term laser irradiation primarily reduced the transmittance, while environmental rays had a minor impact on the same. This work provides valuable insights into the selection and effective use of glass in optics-based diagnostics.

Zinc transporter LIVI controls epithelial-mesenchymal transition in zebrafish gastrula organizer.

Vertebrate gastrulation is a critical step in the establishment of body plan. During gastrulation, epithelial-mesenchymal transition (EMT) occurs. EMT is one of the central events of embryonic development, organ and tissue regeneration, and cancer metastasis. Signal transducers and activators of transcription (STATs) mediate biological actions such as cell proliferation, differentiation and survival in response to cytokines and growth factors, in a variety of biological processes. STATs are also important in EMT during gastrulation, organogenesis, wound healing and cancer progression. We previously showed that STAT3 is activated in the organizer during zebrafish gastrulation and its activity is essential for gastrulation movements. The requirement for STAT3 is cell-autonomous for the anterior migration of gastrula organizer cells, and non-cell-autonomous for the convergence of neighbouring cells. The molecular mechanisms of STAT's action in EMT, however, are unknown. Here we identify LIV1, a breast-cancer-associated zinc transporter protein, as a downstream target of STAT3 that is essential and sufficient for STAT3's cell-autonomous role in the EMT of zebrafish gastrula organizer cells. Furthermore, we demonstrate that LIV1 is essential for the nuclear localization of zinc-finger protein Snail, a master regulator of EMT. These results establish a molecular link between STAT3, LIV1 and Snail in EMT.

[Effects of arbuscular mycorrhizal fungi on metabolism of aroma substances in tobacco]. / ä¸›æžèŒæ ¹çœŸèŒå¯¹çƒŸè‰é¦™æ°”ç›¸å ³ç‰©è´¨ä»£è°¢çš„å½±å“.

Arbuscular mycorrhizal fungi (AMF) can promote nutrient absorption and improve stress resistance of host plants. The effects of AMF on aroma substance metabolism were rarely examined. In this study, we investigated the effects of AMF (Glomus mosseae) on glands and metabolism of aroma substances in tobacco leaves. The results showed that the density of gland hair and the relative expression of the glandular-specific lipid transporter gene NtLTP1, which was necessary to induce lipid secretion, were higher in the leaves of tobacco inoculated with AMF. The content of main aroma substances in tobacco leaves, such as carotenoids, chlorogenic acid and solanesol, were increased. Moreover, AMF inoculation increased the activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO), the key aroma substance synthesis enzymes, and caused upregulation in the relative expression of phenylalanine transaminase, polyphenoloxidase, flavonoids alcoholase and squalene synthase encoding genes. In all, the symbiosis with G. mosseae could increase the abundance and secretory activity of glandular hairs and promote the synthesis of aroma substances in tobacco leaves.