Cortical microstructural brain network mediates the association between personality trait of agreeableness and life satisfaction.

Personality traits are commonly regarded as relatively stable, whereas life satisfaction can fluctuate with time and circumstances, shaped by external influences and personal encounters. The correlation between personality traits and life satisfaction is well-established, yet the underlying neural mechanisms of the myelin-based microstructural brain network connecting them remain unclear. Here, we constructed individual-level whole-brain myelin microstructural networks from the MRI data of 1,043 healthy adults and performed correlation analysis to detect significant personality trait-related and life satisfaction-related subnetworks. A mediation analysis was used to verify whether the shared structural basis of personality traits and life satisfaction significantly mediated their association. The results showed that agreeableness positively correlated with life satisfaction. We identified a shared structural basis of the personality trait of agreeableness and life satisfaction. The regions comprising this overlapping network include the superior parietal lobule, inferior parietal lobule, and temporoparietal junction. Moreover, the shared microstructural connections mediate the association between the personality trait of agreeableness and life satisfaction. This large-scale neuroimaging investigation substantiates a mediation framework for understanding the microstructural connections between personality and life satisfaction, offering potential targets for assessment and interventions to promote human well-being.

Fusarium graminearum rapid alkalinization factor peptide negatively regulates plant immunity and cell growth via the FERONIA receptor kinase.

The plant rapid alkalinization factor (RALF) peptides function as key regulators in cell growth and immune responses through the receptor kinase FERONIA (FER). In this study, we report that the transcription factor FgPacC binds directly to the promoter of FgRALF gene, which encodes a functional homologue of the plant RALF peptides from the wheat head blight fungus Fusarium graminearum (FgRALF). More importantly, FgPacC promotes fungal infection via host immune suppression by activating the expression of FgRALF. The FgRALF peptide also exhibited typical activities of plant RALF functions, such as inducing plant alkalinization and inhibiting cell growth, including wheat (Triticum aestivum), tomato (Solanum lycopersicum) and Arabidopsis thaliana. We further identified the wheat receptor kinase FERONIA (TaFER), which is capable of restoring the defects of the A. thaliana FER mutant. In addition, we found that FgRALF peptide binds to the extracellular malectin-like domain (ECD) of TaFER (TaFERECD) to suppress the PAMP-triggered immunity (PTI) and cell growth. Overexpression of TaFERECD in A. thaliana confers plant resistance to F. graminearum and protects from FgRALF-induced cell growth inhibition. Collectively, our results demonstrate that the fungal pathogen-secreted RALF mimic suppresses host immunity and inhibits cell growth via plant FER receptor. This establishes a novel pathway for the development of disease-resistant crops in the future without compromising their yield potential.

Subcortical structural covariance predicts symptoms in children with different subtypes of ADHD.

Attention-deficit/hyperactivity disorder has increasingly been conceptualized as a disorder of abnormal brain connectivity. However, far less is known about the structural covariance in different subtypes of this disorder and how those differences may contribute to the symptomology of these subtypes. In this study, we used a combined volumetric-based methodology and structural covariance approach to investigate structural covariance of subcortical brain volume in attention-deficit/hyperactivity disorder-combined and attention-deficit/hyperactivity disorder-inattentive patients. In addition, a linear support vector machine was used to predict patient's attention-deficit/hyperactivity disorder symptoms. Results showed that compared with TD children, those with attention-deficit/hyperactivity disorder-combined exhibited decreased volume of both the left and right pallidum. Moreover, we found increased right hippocampal volume in attention-deficit/hyperactivity disorder-inattentive children. Furthermore and when compared with the TD group, both attention-deficit/hyperactivity disorder-combined and attention-deficit/hyperactivity disorder-inattentive groups showed greater nonhomologous inter-regional correlations. The abnormal structural covariance network in the attention-deficit/hyperactivity disorder-combined group was located in the left amygdala-left putamen/left pallidum/right pallidum and right pallidum-left pallidum; in the attention-deficit/hyperactivity disorder-inattentive group, this difference was noted in the left hippocampus-left amygdala/left putamen/right putamen and right hippocampus-left amygdala. Additionally, different combinations of abnormalities in subcortical structural covariance were predictive of symptom severity in different attention-deficit/hyperactivity disorder subtypes. Collectively, our findings demonstrated that structural covariance provided valuable diagnostic markers for attention-deficit/hyperactivity disorder subtypes.

Inhibition of histone acetyltransferase GCN5 by a transcription factor FgPacC controls fungal adaption to host-derived iron stress.

Poaceae plants can locally accumulate iron to suppress pathogen infection. It remains unknown how pathogens overcome host-derived iron stress during their successful infections. Here, we report that Fusarium graminearum (Fg), a destructive fungal pathogen of cereal crops, is challenged by host-derived high-iron stress. Fg infection induces host alkalinization, and the pH-dependent transcription factor FgPacC undergoes a proteolytic cleavage into the functional isoform named FgPacC30 under alkaline host environment. Subsequently FgPacC30 binds to a GCCAR(R = A/G)G element at the promoters of the genes involved in iron uptake and inhibits their expression, leading to adaption of Fg to high-iron stress. Mechanistically, FgPacC30 binds to FgGcn5 protein, a catalytic subunit of Spt-Ada-Gcn5 Acetyltransferase (SAGA) complex, leading to deregulation of histone acetylation at H3K18 and H2BK11, and repression of iron uptake genes. Moreover, we identified a protein kinase FgHal4, which is highly induced by extracellular high-iron stress and protects FgPacC30 against 26S proteasome-dependent degradation by promoting FgPacC30 phosphorylation at Ser2. Collectively, this study uncovers a novel inhibitory mechanism of the SAGA complex by a transcription factor that enables a fungal pathogen to adapt to dynamic microenvironments during infection.

Bio-perfume guns: Antifungal volatile activity of Bacillus sp. LNXM12 against postharvest pathogen Botrytis cinerea in tomato and strawberry.

Gray mold disease, caused by Botrytis cinerea is a major postharvest disease impacting fruits such as strawberries and tomatoes. This study explores the use of volatile organic compounds (VOCs) produced by Bacillus spp. as eco-friendly biocontrol agents against B. cinerea. In vitro experiments demonstrated that VOCs from Bacillus sp. LNXM12, B. thuringiensis GBAC46, and B. zhanghouensis LLTC93-VOCs inhibited fungal growth by 61.2%, 40.5%, and 21.6%, respectively, compared to the control. LNXM12 was selected for further experiments due to its highest control efficacy of 58.3% and 76.6% on tomato and strawberry fruits, respectively. The LNXM12 VOCs were identified through gas chromatography-mass spectrometry (GC-MS) analysis, and 22 VOCs were identified. Synthetic VOCs with the highest probability percentage, namely ethyloctynol, 3-methyl-2-pentanone (3M2P), 1,3-butadiene-N, N-dimethylformamide (DMF), and squalene were used in experiments. The results showed that the synthetic VOCs ethyloctynol and 3M2P were highly effective, with an inhibition rate of 56.8 and 57.1% against fungal mycelium radial growth at 120 µg/mL on agar plates. Trypan blue staining revealed strongly disrupted, deeper blue, and lysed mycelium in VOC-treated B. cinerea. The scanning and transmission electron microscope (SEM and TEM) results showed that fungal mycelium was smaller, irregular, and shrunken after synthetic VOC treatments. Furthermore, the synthetic VOCs Ethyloctynol and 3M2P revealed high control efficacy on tomatoes and strawberries infected by B. cinerea. The control efficacy on leaves was 67.2%, 66.1% and 64.5%, 78.4% respectively. Similarly, the control efficiency on fruits was 45.5%, 67.3% and 46.3% 65.1%. The expression of virulence genes in B. cinerea was analyzed, and the results revealed that selected genes BcSpl1, BcXyn11A, BcPG2, BcNoxB, BcNoxR, and BcPG1 were downregulated after VOCs treatment. The overall result revealed novel mechanisms by which Bacillus sp. volatiles control postharvest gray mold disease.

Transcriptomic analysis of Ralstonia solanacearum in response to antibacterial volatiles of Bacillus velezensis FZB42.

Volatile organic compounds (VOCs), produced by a variety of microbial species and used as biological agents, have been demonstrated to play a significant role in controlling phytopathogens. In continuation of our previous studies, we aim to elucidate the underlying mechanisms and pathways involved in interactions between pathogens and microbial VOCs. In the current study, we tested how VOCs produced by Bacillus velezensis FZB42 affect the growth of Ralstonia solanacearum TBBS1 in vitro.Query The result showed that the colony growth of R. solanacearum was reduced with an inhibition rate of 0.83 ± 0.043 as compared to the control 1.7 ± 0.076, respectively. The number of viable cells of R. solanacearum was significantly decreased to 7.68 CFU/mL as compared to the control (9.02 CFU/mL). In addition, transcriptomic analysis of R. solanacearum in response to VOCs produced by FZB42 was performed to better understand the effect of VOCs on R. solanacearum. The transcriptional response of R. solanacearum to FZB42-VOCs was determined using an Illumina RNA-seq approach. The results revealed significant changes in the expression of 2094 R. solanacearum genes, including 593 upregulated and 1501 downregulated genes. To validate the RNA-seq results, the expression of 10 genes was quantified using RT-qPCR. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were used to functionally annotate differentially expressed genes. Significant changes were observed in genes directly or indirectly related to virulence, including those related to bacterial invasion, motility, chemotaxis, and secretion systems. Overall, RNA-seq profiling provides new insights into the possible fundamental molecular mechanisms that are responsible for the reduction in growth and virulence of R. solanacearum upon application of FZB42-VOC.

High killing rate of nematode and promotion of rice growth by synthetic volatiles from Bacillus strains due to enhanced oxidative stress response.

The plant parasitic nematode Aphelenchoides besseyi is a major pest that poses serious threats to different vegetables and crop plants. In the present study, volatiles isolated from Bacillus spp. were utilized as green biocontrol agents to overcome nematodes. In in vitro experiment, Bacillus spp. GBSC56, SYST2, and FZB42 showed the strongest nematicidal activity with killing rates of 80.78%, 75.69%, and 60.45%, respectively, as compared with control. The selected synthetic volatile organic compounds (VOCs), namely albuterol, benzaldehyde (BDH), 1,2-benzisothiazol-3(2H)-one (1,2-HIT), dimethyl disulfide (DMDS), 2-undecanone (2-UD), and 1,3-propanediole (1,3-PD), exhibited strong nematicidal activity, with A. besseyi killing rate of 85.58%, 82.65%, 81.75%, 80.36%, 84.45%, and 82.36%, respectively, at 400 µg/mL. Microscopic analysis proved that the rapid mortality was due to the production of reactive oxygen species (ROS). Molecular docking attributed this ROS production to the nematicidal effect of synthetic VOCs on NADH DEHYDROGENASE SUBUNIT 2, which is known to play a critical role in the suppression of ROS in nematode models. In a greenhouse experiment, the Bacillus strains GBSC56, SYST2, and FZB42 and their synthetic VOCs significantly improved the physiological parameters in terms of growth promotion traits. In addition, selected genes related to growth promotion and defense genes showed a significant upregulation of their expression in rice seedlings treated with those synthetic VOCs. Overall, these findings revealed that the selected Bacillus strains and their synthetic VOCs possess high potential against A. besseyi. Moreover, this study also sheds new light on the mechanisms by which specific Bacillus nematicidal VOCs influence important genes involved in rice plant growth promotion and could effectively be used to suppress plant parasitic nematodes.

Broad-spectrum antagonistic potential of Bacillus spp. volatiles against Rhizoctonia solani and Xanthomonas oryzae pv. oryzae.

Rhizoctonia solani and Xanthomonas oryzae pv. oryzae (Xoo) are the two major diseases affecting the quality and quantity of rice production. In the current study, volatile organic compounds (VOCs) of Bacillus spp. were used as green biocontrol agents for plant diseases. In in vitro experiments, Bacillus spp. FZB42, NMTD17, and LLTC93-VOCs displayed strong antimicrobial volatile activity with inhibition rates of 76, 66, and 78% for R. solani and 78, 81, and 76% for Xoo, respectively, compared to control. The synthetic VOCs, namely Pentadecane (PDC), Benzaldehyde (BDH), 1,2-Benz isothiazol-3(2H)-one (1,2-BIT), and mixture (MIX) of VOCs showed high volatile activity with inhibition rates of 86, 86, 89, and 92% against R. solani and 81, 81, 82, and 86%, respectively, against Xoo as compared to control. In addition, the scanning and transmission electron microscopes (SEM and TEM) analyses were performed to examine the effect of Bacillus and synthetic VOC treatments on R. solani and Xoo morphology. The analysis revealed the deformed and irregularized morphology of R. solani mycelia and Xoo cells after VOC treatments. The microscopic analysis showed that the rapid inhibition was due to severe oxidative productions inside the R. solani mycelia and Xoo cells. By using molecular docking, it was determined that the synthetic VOCs entered the active binding site of trehalase and NADH dehydrogenase proteins, causing R. solani and Xoo cells to die prematurely and an accumulation of ROS. In the greenhouse experiment, FZB42, NMTD17, and LLTC93-VOCs significantly reduced the lesions of R. solani 8, 7, and 6 cm, and Xoo 7, 6, and 6 cm, respectively, then control. The synthetic VOCs demonstrated that the PDC, BDH, 1,2-BIT, and MIX-VOCs significantly reduced R. solani lesions on leaves 6, 6, 6, and 5 cm and Xoo 6, 5, 5, and 4 cm, respectively, as compared to control. Furthermore, plant defence-related genes and antioxidant enzymes were upregulated in rice plants. These findings provide novel mechanisms by which Bacillus antimicrobial VOCs control plant diseases.

Structural Brain Changes and Associated Symptoms of ADHD Subtypes in Children.

Attention-deficit/hyperactivity disorder (ADHD) is presumed to be heterogeneous, but the best way to characterize this heterogeneity remains unclear. Although considerable evidence suggests that the 2 different types of ADHD, inattention and combined, have different cognitive and behavioral profiles, and underlying neurobiologies, we currently lack information on whether these subtypes reflect separated brain structure changes. Structural magnetic resonance imaging scans (N = 234), diagnostic, and demographic information were obtained from the ADHD-200 database. Of this sample, 138 were Typically Developing people, 37 were ADHD-Combined, and 59 were ADHD-Inattentive patients. Freesurfer segmentation methods were used to measure cortical thickness, area, and volume, subcortical volume and hipposubfield volume. ADHD-Inattentive patients showed milder clinical symptoms but more serious cognitive injury than ADHD-Combined patients. In addition, dissociable structural brain changes were found in different subtypes of ADHD, particularly in terms of decreased subcortical volume in ADHD-Combined patients compared with Typically Developing people. Clinical symptoms were predominantly related to smaller rh_caudalanteriorcingulate thickness and left-Pallidum volume, whereas verbal IQ injury was correlated strongly with smaller rh_insula area. These findings indicate that there are significant differences in clinical symptoms and gray matter damage between ADHD-Combined and -Inattentive patients. This supports the growing evidence of heterogeneity in the ADHD-Inattentive subtype and the evidence of brain structure differences.

The collaborative monitored natural attenuation (CMNA) of soil and groundwater pollution in large petrochemical enterprises: A case study.

A large in-service petrochemical enterprises in Northeast China was taken as the research object, and the Collaborative Monitored Natural Attenuation (CMNA) for soil and groundwater pollution was carried out to remedy combined pollution and reduce environmental risks. The pollutants distributions were obtained based on detailed regional investigation (Mar. 2019), and feature pollutants in soil and groundwater were then screened. The spatiotemporal variations of feature pollutants and relative microbial responses were explored during the CMNA process. Furthermore, the CMNA efficiency of the contaminated site at initial stage was evaluated by calculation of natural attenuation rate constant. The results showed that the feature pollutants in soil were 2,2',5,5'-tetrachlorobiphenyl (2,2',5,5'-TCB) and petroleum hydrocarbons (C10∼C40), and the feature pollutant in groundwater was 1,2-dichloroethane (1,2-DCA). The concentrations of all feature pollutants decreased continuously during four years of monitoring. Feature pollutants played a dominant role in the variability of microbial species both in soil and groundwater, increasing the relative abundance of petroleum tolerant/biodegradation bacteria, such as Actinobacteria, Proteobacteria and Acidobacteriota. The average natural attenuation rate constant of 2,2',5,5'-TCB and C10∼C40 in soil was 0.0012 d-1 and 0.0010 d-1, respectively, meeting the screening value after four years' attenuation. The average natural attenuation rate constant of 1,2-DCA was 0.0004 d-1, which need strengthening measures to improve the attenuation efficiency.

Uncovering the spatio-temporal dynamics of crop-specific nutrient budgets in China.

Nitrogen (N) and phosphorus (P) are two critical nutrients for agroecosystems. In meeting food demands, human use of both nutrients has crossed planetary boundaries for sustainability. Further, there has been a dramatic shift in their relative inputs and outputs, which may generate strong N:P imbalances. Despite enormous efforts on agronomic N and P budgets, the spatio-temporal characteristics of different crop types in using nutrients are unknown as are patterns in the stoichiometric coupling of these nutrients. Thus, we analyzed the annual crop-specific N and P budgets and their stoichiometric relations for producing ten major crops at the provincial level of China during 2004-2018. Results show that, China has generally witnessed excessive N and P input over the past 15 years, with the N balance remaining stable while the P balance increasing by more than 170%, thus resulting in a decline in the N:P mass ratios from 10.9 in 2004 to 3.8 in 2018. Crop-aggregated nutrient use efficiency (NUE) of N has increased by 10% in these years while most crops have shown a decreasing trend of this indicator for P, which reduced NUE of P from 75% to 61% during this period. At the provincial level, the nutrient fluxes of Beijing and Shanghai have obviously declined, while the nutrient fluxes of provinces such as Xinjiang and Inner Mongolia have increased significantly. Although N management has made progress, P management should be further explored in the future due to eutrophication concerns. More importantly, N and P management strategies for sustainable agriculture in China should take account of not only the absolute nutrient use, but also their stoichiometric balance for different crops in different locations.

Imparting pH and temperature dual-responsiveness in a micellar solution of cationic surfactants by introducing a hydrotrope.

Over the recent years, intelligent, multi-responsive micelles have received considerable attention due to their promising application in a variety of fields, including biomedical technology, drug delivery, separation, and catalysis. However, the design of such systems with controlled self-assembly is challenging both experimentally and theoretically and is still in the nascent stage. In this study, a novel dual-stimuli triggered wormlike micellar solution is prepared by mixing cationic surfactants 3-hexadecyloxy-2-hydroxypropyltrimethylammonium bromide (R16HTAB) and sodium hydrogen phthalate (SHP). The viscoelasticity, aggregate morphology, and pH- and thermo-responsive behavior of the micellar solution are examined by rheological measurements, cryogenic-transmission electron microscopy (cryo-TEM), nuclear magnetic resonance (1H NMR) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The dual-sensitive fluid can be switched between a water-like state and a gel-like state by adjusting the pH and temperature. The variations in the flowing behavior are ascribed to the microstructural transition between wormlike micelles, short cylindrical micelles, and spherical micelles. Furthermore, based on the experimental results, dual-responsive behavior of the mixed solution is attributed to the different binding modes between SHP and the surfactant with the variation in the pH and temperature. We hope that the proposed system provides a new route for developing multi-stimuli-responsive materials that are capable of adapting to local environmental variations.

NLRP3 inflammasome inhibitor ameliorates ischemic stroke by reprogramming the phenotype of microglia/macrophage in a murine model of distal middle cerebral artery occlusion.

Stroke is one of the leading causes of death and disability worldwide. NLRP3 inflammasome has an essential role in the neuropathology of stroke. Recent studies report that shifting the microglial M1 phenotype to the M2 phenotype protects against ischemic stroke. In the present study, the precise effects of Tranilast, a NLPR3 inflammasome inhibitor, on stroke were evaluated. We established a murine model of distal middle cerebral artery occlusion (dMCAO) and administered Tranilast to dMCAO-induced stroke mice. The NLRP3 level, caspase 1 activity, and infarct volume stroke mice were measured. The sensorimotor function, pro-inflammatory cytokine production, and M1/M2 marker expression were measured. The M1 phenotype was induced by treatment of BV2 microglia with lipopolysacharide and interferon γ, and these BV-2 cells were further treated with Tranilast. The expression of CD16 and CD206 was monitored. dMCAO increased the NLRP3 expression and enhanced caspase 1 activity. Tranilast treatment significantly decreased the infarct volume, improved sensorimotor function, and suppressed the production of inflammatory cytokines in stroke mice. Moreover, Tranilast decreased the M1 marker level while promoting the expression of M2 markers. In summary, our findings suggest that Tranilast ameliorates ischemic stroke through stimulating M2 polarization of microglia.

Toxicity of Bacillus thuringiensis Strains Derived from the Novel Crystal Protein Cry31Aa with High Nematicidal Activity against Rice Parasitic Nematode Aphelenchoides besseyi.

The plant parasitic nematode, Aphelenchoides besseyi, is a serious pest causing severe damage to various crop plants and vegetables. The Bacillus thuringiensis (Bt) strains, GBAC46 and NMTD81, and the biological strain, FZB42, showed higher nematicidal activity against A. besseyi, by up to 88.80, 82.65, and 75.87%, respectively, in a 96-well plate experiment. We screened the whole genomes of the selected strains by protein-nucleic acid alignment. It was found that the Bt strain GBAC46 showed three novel crystal proteins, namely, Cry31Aa, Cry73Aa, and Cry40ORF, which likely provide for the safe control of nematodes. The Cry31Aa protein was composed of 802 amino acids with a molecular weight of 90.257 kDa and contained a conserved delta-endotoxin insecticidal domain. The Cry31Aa exhibited significant nematicidal activity against A. besseyi with a lethal concentration (LC50) value of 131.80 µg/mL. Furthermore, the results of in vitro experiments (i.e., rhodamine and propidium iodide (PI) experiments) revealed that the Cry31Aa protein was taken up by A. besseyi, which caused damage to the nematode's intestinal cell membrane, indicating that the Cry31Aa produced a pore-formation toxin. In pot experiments, the selected strains GBAC46, NMTD81, and FZB42 significantly reduced the lesions on leaves by up to 33.56%, 45.66, and 30.34% and also enhanced physiological growth parameters such as root length (65.10, 50.65, and 55.60%), shoot length (68.10, 55.60, and 59.45%), and plant fresh weight (60.71, 56.45, and 55.65%), respectively. The number of nematodes obtained from the plants treated with the selected strains (i.e., GBAC46, NMTD81, and FZB42) and A. besseyi was significantly reduced, with 0.56, 0.83., 1.11, and 5.04 seedling mL-1 nematodes were achieved, respectively. Moreover, the qRT-PCR analysis showed that the defense-related genes were upregulated, and the activity of hydrogen peroxide (H2O2) increased while malondialdehyde (MDA) decreased in rice leaves compared to the control. Therefore, it was concluded that the Bt strains GBAC46 and NMTD81 can promote rice growth, induce high expression of rice defense-related genes, and activate systemic resistance in rice. More importantly, the application of the novel Cry31Aa protein has high potential for the efficient and safe prevention and green control of plant parasitic nematodes.

The Role of Pyoluteorin from Pseudomonas protegens Pf-5 in Suppressing the Growth and Pathogenicity of Pantoea ananatis on Maize.

The rhizospheric bacterium Pseudomonas protegens Pf-5 can colonize the seed and root surfaces of plants, and can protect them from pathogen infection. Secondary metabolites, including lipopeptides and polyketides produced by Pf-5, are involved in its biocontrol activity. We isolated a crude extract from Pf-5. It exhibited significant surface activity and strong antibacterial activity against Pantoea ananatis DZ-12, which causes maize brown rot on leaves. HPLC analysis combined with activity tests showed that the polyketide pyoluteorin in the crude extract participated in the suppression of DZ-12 growth, and that the lipopeptide orfamide A was the major biosurfactant in the crude extract. Further studies indicated that the pyoluteorin in the crude extract significantly suppressed the biofilm formation of DZ-12, and it induced the accumulation of reactive oxygen species in DZ-12 cells. Scanning electron microscopy and transmission electron microscopy observation revealed that the crude extract severely damaged the pathogen cells and caused cytoplasmic extravasations and hollowing of the cells. The pathogenicity of DZ-12 on maize leaves was significantly reduced by the crude extract from Pf-5 in a dose-dependent manner. The polyketide pyoluteorin had strong antibacterial activity against DZ-12, and it has the potential for development as an antimicrobial agent.

Lysobacter enzymogenes antagonizes soilborne bacteria using the type IV secretion system.

Soil microbiome comprises numerous microbial species that continuously interact with each other. Among the modes of diverse interactions, cell-cell killing may play a key role in shaping the microbiome composition. Bacteria deploy various secretion systems to fend off other microorganisms and Type IV Secretion System (T4SS) in pathogenic bacteria was shown to function as a contact-dependent, inter-bacterial killing system only recently. The present study investigated the role played by T4SS in the killing behaviour of the soilborne biocontrol bacterium Lysobacter enzymogenes OH11. Results showed that L. enzymogenes OH11 genome encompasses genes encoding all the components of T4SS and effectors potentially involved in inter-bacterial killing system. Generation of knock-out mutants revealed that L. enzymogenes OH11 uses T4SS as the main contact-dependent weapon against other soilborne bacteria. The T4SS-mediated killing behaviour of L. enzymogenes OH11 decreased the antibacterial and antifungal activity of two Pseudomonas spp. but at the same time, protected carrot from infection by Pectobacterium carotovorum. Overall, this study showed for the first time the involvement of T4SS in the killing behaviour of L. enzymogenes and its impact on the multiple interactions occurring in the soil microbiome.

A pH, thermal and light triple-stimuli responsive micellar solution formed by a cationic surfactant and trans-o-hydroxycinnamic acid.

Controlling the viscoelastic characteristics of wormlike micelles is of great significance to both basic theory and practical applications. In this article, a novel multi-stimuli responsive wormlike micellar solution was prepared by mixing cationic surfactant 3-hexadecyloxy-2-hydroxypropyltrimethylammonium bromide (R16HTAB) with trans-o-hydroxycinnamic acid (OHCA). Rheological studies, nuclear magnetic resonance (1H-NMR) spectroscopy, UV-vis spectroscopy, and cryogenic-transmission electron microscopy (cryo-TEM) were utilized to investigate the wormlike micellar system's multi-responsive activity. The results showed that the self-assembled structure and viscoelasticity of the mixed system could be regulated by pH, temperature, and light irradiation. With the increasing trans-OHCA concentration, η0 of the mixed solution increases first and then decreases and the turning point is presented at 30 mM trans-OHCA, indicating the transformation of spherical micelles to wormlike micelles, and then to short micelles. The microstructure of the mixed systems could be reversibly altered by adjusting the pH between 6.41 and 3.90, which was ascertained by cryogenic-transmission electron microscopy (cryo-TEM). The relationship of temperature and η0 obeys the Arrhenius law, attributed to the decreasing micellar contour length. η0 of a 40 mM R16HTAB/15 mM OHCA solution sharply increases after UV irradiation, mainly because the cis-isomer could insert into the micelle more easily, and the transition mechanism was studied by UV-vis and 1H NMR. The multi-responsive self-assembled system may open a new vista for building multi-functional aggregates to adapt to various environmental changes.

5-Methoxyindole, a Chemical Homolog of Melatonin, Adversely Affects the Phytopathogenic Fungus Fusarium graminearum.

Fusarium graminearum is a destructive fungal pathogen that threatens the production and quality of wheat, and controlling this pathogen is a significant challenge. As the cost-effective homolog of melatonin, 5-methoxyindole showed strong activity against F. graminearum. In the present study, our results showed the strong adverse activity of 5-methoxyindole against F. graminearum by inhibiting its growth, formation, and conidia germination. In addition, 5-methoxyindole could induce malformation, reactive oxygen species (ROS) accumulation, and cell death in F. graminearum hyphae and conidia. In response to 5-methoxyindole, F. graminearum genes involved in scavenging reactive oxygen species were significantly downregulated. Overall, these findings reveal the mechanism of antifungal action of melatonin-homolog 5-methoxyindole. To the best of our knowledge, this is the first report that a novel melatonin homolog confers strong antifungal activity against F. graminearum, and 5-methoxyindole is a potential compound for protecting wheat plants from F. graminearum infection.

Novel Genetic Dysregulations and Oxidative Damage in Fusarium graminearum Induced by Plant Defense Eliciting Psychrophilic Bacillus atrophaeus TS1.

This study elaborates inter-kingdom signaling mechanisms, presenting a sustainable and eco-friendly approach to combat biotic as well as abiotic stress in wheat. Fusarium graminearum is a devastating pathogen causing head and seedling blight in wheat, leading to huge yield and economic losses. Psychrophilic Bacillus atrophaeus strain TS1 was found as a potential biocontrol agent for suppression of F. graminearum under low temperature by carrying out extensive biochemical and molecular studies in comparison with a temperate biocontrol model strain Bacillus amyloliquefaciens FZB42 at 15 and 25 °C. TS1 was able to produce hydrolytic extracellular enzymes as well as antimicrobial lipopeptides, i.e., surfactin, bacillomycin, and fengycin, efficiently at low temperatures. The Bacillus strain-induced oxidative cellular damage, ultrastructural deformities, and novel genetic dysregulations in the fungal pathogen as the bacterial treatment at low temperature were able to downregulate the expression of newly predicted novel fungal genes potentially belonging to necrosis inducing protein families (fgHCE and fgNPP1). The wheat pot experiments conducted at 15 and 25 °C revealed the potential of TS1 to elicit sudden induction of plant defense, namely, H2O2 and callose enhanced activity of plant defense-related enzymes and induced over-expression of defense-related genes which accumulatively lead to the suppression of F. graminearum and decreased diseased leaf area.

The "pseudo-pathogenic" effect of plant growth-promoting Bacilli on starchy plant storage organs is due to their α-amylase activity which is stimulating endogenous opportunistic pathogens.

Many representatives of the Bacillus subtilis species complex are known as plant growth-promoting rhizobacteria (PGPR) and are widely used in agriculture as biofertilizers and biocontrol agents. Two bacterial strains, "Korea isolate" and ZL918, taxonomically classified as being Bacillus amyloliquefaciens, isolated from disease-damaged plant organs, were alleged to cause bacterial rot in starchy storage plant organs. The aim of this study was to elucidate whether these findings have consequences for the general use of beneficial Bacilli in agriculture. Whole genome sequencing revealed that the pathogenic ZL918 was a representative of Bacillus velezensis. B. velezensis FZB42 and other representatives of the B. subtilis species complex caused the same symptoms of bacterial rot only when injected inside of potato tubers and onion bulbs, but not when inoculated onto the surface of the storage organs. It seemed that the pathogenic effect was due to starch hydrolyzing activity that likely stimulates propagation of endophytic bacteria inside of starchy tissues. After removing the inherent microbiota via Co60 γ-ray irradiation, the storage organs inoculated by either FZB42 or purified α-amylase did not develop rot symptoms. Two opportunistic pathogens, Pantoea ananatis and Pantoea agglomerans, isolated from the rotted area, were shown to cause bacterial rot in x-ray treated potato tuber and onion starchy tissues when the proteobacteria were applied in high concentration. This suggests that opportunistic pathogenic bacteria residing inside of the starchy storage organ are the causal agents of bacterial soft rot disease in potato tubers and other starchy plant storage organs.