Search Results (2,280)

Background: The intracellular pathogen Brucella requires biotin for survival, yet the role of its de novo synthesis intermediate enzyme, BioA, in virulence remains undefined. This study investigates the contribution of BioA to the pathogenicity of Brucella abortus. Methods: We constructed a ΔBioA mutant in Brucella abortus 104M via homologous recombination and characterized its phenotype using growth assays, electron microscopy, macrophage infection models, and murine splenic colonization. Virulence gene expression was quantified by RT-qPCR. Results: The ΔBioA mutant exhibited severe growth auxotrophy in a biotin-deficient medium and displayed damaged outer membrane integrity. Furthermore, intracellular survival in macrophages was reduced by approximately 95% compared to the wild-type strain at 48 h post-infection. Notably, mice infected with the mutant showed a significant decrease in both splenic bacterial loads and spleen weight at 3 weeks, concomitant with a marked downregulation of VirB type IV secretion system (T4SS) genes. Conclusions: This study is the first to identify BioA as a critical nexus linking biotin metabolism to Brucella virulence. We demonstrate that BioA deficiency attenuates pathogenicity by impairing both structural integrity and the transcription of key virulence-related genes (VirB operon), thereby nominating BioA as a novel and promising target for anti-brucellosis interventions. Full article

Integrating biochar with plant growth-promoting rhizobacteria (PGPR) is a promising strategy for sustainable soil management; however, the synergistic mechanisms governing rhizosphere microbial assembly remain inadequately understood. In this study, we investigated the combined effects of maize biochar (YM) and Bacillus amyloliquefaciens (BA) on tomato performance, soil physicochemical properties, and bacterial community dynamics via a controlled pot experiment. The results demonstrated that the synergistic treatment (YMBA) significantly enhanced tomato yield by 18.3% compared to the control, outperforming individual applications. This promotion was coupled with a comprehensive improvement in soil fertility, characterized by significant increases in soil organic matter (SOM), available nutrients (N, P, and K), and the activities of urease and acid phosphatase. High-throughput sequencing revealed that YMBA treatment significantly restructured the rhizosphere bacterial community, significantly increasing microbial richness and diversity. Notably, the synergistic application promoted the recruitment of beneficial taxa, particularly within the phylum Pseudomonadota. Mantel test analysis further elucidated that SOM and available phosphorus (AP) were the primary environmental drivers shaping the bacterial community turnover. Our findings suggest that biochar acts as a functional niche that facilitates B. amyloliquefaciens colonization and modulates the indigenous microbiota, providing a theoretical framework for utilizing cross-trophic synergies to optimize crop productivity and soil health. Full article

Neonatal infections remain a leading cause of morbidity and mortality worldwide, particularly among preterm and low-birth-weight infants and in low- and middle-income countries. This burden has intensified with the global increase in multidrug-resistant (MDR) bacteria, especially in neonatal intensive care units, where prolonged hospitalization, invasive interventions, and exposure to broad-spectrum antibiotics promote colonization, transmission, and invasive infection. In this narrative review, we explore the epidemiology and microbiological characteristics of MDR bacterial infections in newborns, alongside their associated risk factors, diagnostic challenges, treatment outcomes, and prevention strategies. Across different settings, Gram-negative pathogens, particularly Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii, account for a substantial proportion of severe neonatal infections, whereas methicillin-resistant Staphylococcus aureus remains important in selected units. The risk of MDR infection is driven by a complex interplay of factors, ranging from maternal and perinatal exposures to the inherent immunological vulnerability of newborns, hospital-based transmission, antibiotic selection pressure, and structural deficiencies in healthcare infrastructure. Diagnosis remains challenging because clinical presentations are nonspecific and culture-based methods are constrained by low blood volumes, prior antimicrobial exposure, and delayed turnaround times. Treatment is increasingly complicated due to resistance to standard empirical regimens, substantial regional variation in susceptibility profiles, and limited neonatal pharmacokinetic and safety data for reserve agents. Current evidence mainly supports surveillance-informed empirical therapy, susceptibility-guided treatment adjustment, antimicrobial stewardship, and strict infection prevention measures. Future progress will require neonatal-specific clinical trials, harmonized surveillance systems, stronger molecular epidemiology, and more equitable access to microbiological diagnostics and effective treatment. Full article

Microbial communities associated with the rhizosphere and phyllosphere are recognized as fundamental components influencing essential plant processes, including nutrient acquisition, growth promotion, and tolerance to stress. Biological control agents (BCAs), such as Trichoderma spp. and Bacillus spp., are widely applied in citrus crops. However, while BCAs effectiveness against plant pathogens is widely established, their resulting impact on indigenous, non-target bacterial and fungal communities remains poorly understood. The aim of this study was to evaluate the non-target effects of two commercial microbial formulations—one containing Trichoderma asperellum ICC 012 and T. gamsii ICC 080, and the other Bacillus amyloliquefaciens QST 713—on the resident microbiomes of Citrus volkameriana seedlings by using the amplicon-based metagenomic analysis, targeting the 16S rRNA and ITS1 regions. The application of the Trichoderma formulation as a soil drench in the rhizosphere resulted in minimal changes to the overall composition and diversity (α- and β-diversity) of the bacterial communities. This stability is considered a desirable trait for overall soil health. However, specific taxonomic changes were observed, such as a notable decrease in the genus Rhodococcus (0.4% vs. 1.5% in controls) among bacteria. In the fungal communities, the treatment led to a significant shift in phylum relative abundance, characterized by an increase in Basidiomycota (38% vs. 28% in controls) and a corresponding decrease in Ascomycota (51% vs. 56% in controls). Successful colonization was confirmed by a substantially higher relative abundance of the inoculated Trichoderma genus compared to control plants (1.4% vs. 0.1% in controls). Conversely, the foliar application of the Bacillus product induced a substantial restructuring of the phyllosphere bacterial community. This treatment caused a statistically significant reduction in bacterial α-diversity and a clear differentiation in community composition (β-diversity) relative to untreated controls. The successful colonization by the BCA resulted in the dominance of the Bacillus genus in the treated samples (27% vs. 2% in controls). Importantly, this ecological shift was accompanied by the enrichment of other beneficial bacterial taxa, including Sphingomonas (15% vs. 4% in controls) and the Burkholderia-Caballeronia-Paraburkholderia group (4% vs. 2% in controls). While fungal phyla abundances remained generally stable in the phyllosphere, specific genera such as Cladosporium (15% vs. 23% in controls) and Symmetrospora (21% vs. 13% in controls) prevailed post-treatment. In conclusion, these findings highlight the importance of considering non-target microbiome shift when implementing microbial biocontrol strategies in citrus production systems, since in this study was demonstrated that commercial BCAs exert a markedly differential influence based on the compartment of application: Trichoderma promoted ecological stability in the rhizosphere, whereas Bacillus induced a directional community shift in the phyllosphere. Full article

Pertussis is a highly contagious respiratory infection caused by Bordetella pertussis and remains a persistent global health challenge despite widespread vaccination. This review aims to analyze the immune pathogenesis of B. pertussis infection and to identify key immunological limitations of current acellular pertussis vaccines that contribute to ongoing transmission. A narrative review of the literature was conducted, focusing on mechanisms of host–pathogen interaction, immune evasion, and vaccine-induced immunity. Evidence indicates that although acellular vaccines effectively reduce disease severity, they fail to prevent nasopharyngeal colonization and transmission, largely due to insufficient induction of mucosal immunity, T helper 1 (Th1) and T helper 17 (Th17) responses, and airway tissue-resident memory T cells. In contrast, natural infection induces broader immune responses, including secretory IgA production and robust cellular immunity, which are associated with improved bacterial clearance. Emerging next-generation vaccine strategies, including mucosal, outer membrane vesicle-based, and live-attenuated platforms, demonstrate enhanced ability to reduce bacterial colonization in preclinical and clinical models. In conclusion, effective control of pertussis transmission will require vaccine approaches that replicate infection-induced immunity at the respiratory mucosa, emphasizing the need for redesigned immunization strategies. Full article

Cancer remains one of the leading causes of morbidity and mortality worldwide, and despite major advances in surgery, chemotherapy, radiotherapy, and immunotherapy, important therapeutic limitations persist, including systemic toxicity, therapeutic resistance, and poor drug penetration into hypoxic tumor regions. These challenges have renewed interest in alternative biological strategies, particularly the use of bacteria and bacterial toxins as antitumor agents. Certain bacterial species possess intrinsic tumor-targeting properties, including the ability to selectively colonize hypoxic and necrotic regions of solid tumors that are poorly accessible to conventional therapies. This review provides a comprehensive analysis of the mechanisms underlying bacteria-mediated anticancer activity, including selective tumor colonization, direct oncolysis, immune activation, and toxin-mediated cytotoxicity. Both obligate anaerobes (e.g., Clostridium and Bifidobacterium) and facultative anaerobes (e.g., Salmonella, Escherichia coli, and Listeria monocytogenes) are examined for their tumor-targeting potential. In addition, we discuss the oncological applications of several bacterial toxins and toxin-derived therapeutic constructs, including Cytolysin A (ClyA), Clostridium difficile toxin B (TcdB), diphtheria toxin, Pseudomonas aeruginosa exotoxin A, and Clostridium perfringens enterotoxin (CPE). Emerging strategies such as recombinant immunotoxins and bacterial-directed enzyme prodrug therapy (BDEPT) are also reviewed. Finally, current translational challenges, including pharmacokinetic limitations, immune clearance, and biosafety considerations, are analyzed, highlighting future directions for integrating bacteria-based platforms into next-generation cancer therapies. This approach reflects the growing interest in microbial strategies for oncology and underscores the potential of bacteria and their toxins as innovative tools in the development of targeted anticancer therapies. Full article

Naturally abundant endophytes colonize plants internally without causing harm to their host plants. Endophytes are likely to occupy the same ecological niches as phytopathogens and thus have a high potential to be effective biological control agents. Their demonstrated ability to suppress more than one plant pathogen suggests that they can offer a viable alternative to chemical fungicides and a strategy for decreasing the inoculum potential of soil-borne pathogens. Some biocontrol endophytes are also known to improve soil health and the overall health of plants. However, the results in greenhouse studies do not always translate to consistent field efficacy. In this study, the efficacy of three endophytic bacterial isolates (PRT (Bacillus subtilis), PSL (Bacillus amyloliquefaciens), and IMC8 (Bacillus thuringiesis) were evaluated against Phytophthora capsici in a field environment and compared with two commercial biological fungicides, Serenade^® (Bayer Crop Science, St Louis MO, USA) and Double Nickel^® (Certis Biologicals, Columbia, MO, USA), and water control. Plants were inoculated with the bacteria strains using seed treatment for early plant colonization before transplanting to a field infested with P. capsici. Treatments with commercial bio-fungicides followed label recommendations. Data on plant growth vigor, disease severity, number of fruits, fruit size, total yield per plant, and percent of diseased fruits displayed significant differences between the bacteria treatments. While PRT was the best treatment for most traits, followed by PSL on pepper, PSL and Double Nickel were the best treatments on tomatoes. IMC8 was best for plant vigor and larger fruit size, but with fewer fruits per plant on both crops. This study suggests bacterial isolates PRT, PSL, and IMC8 can provide additional products for growth promotion and P. capsici disease management in pepper and tomatoes. Full article

Achromobacter spp. are opportunistic pathogens in people with cystic fibrosis (PwCF), yet the role of the upper airways in their persistence and adaptation remains poorly understood. We investigated whether the sinonasal compartment may act as reservoir and evolutionary niche for Achromobacter spp. during airway infection. Twenty-two isolates obtained from paired nasal lavage and sputum samples of seven PwCF were analysed by whole-genome sequencing. Within each PwCF, identical clone types were detected in both airway compartments, supporting bacterial exchange between upper and lower airways. Despite clonal relatedness, substantial genomic diversification was observed between paired isolates. Genomic signatures indicative of elevated mutation rates were detected in a high number of isolates (73%) and in both airway compartments, highlighting widespread genomic diversification across the respiratory tract. Mobilome analysis revealed compartment-specific variations in insertion sequences, prophages, and integrative elements, suggesting genome plasticity. Additionally, mutation in an aspartate kinase gene was consistently associated with loss of biofilm formation in vitro, highlighting a potential link between this pathway and biofilm phenotype. Overall, our findings indicate that upper and lower airways represent interconnected but partially independent ecological niches where Achromobacter populations can diverge during colonization, supporting the view that both compartments contribute to their persistence and evolution in CF airways. Full article

Background: Inflammatory bowel disease (IBD) is a gut-based idiopathic disease characterized by chronic and relapsing inflammatory progression and intricate pathophysiology. It is now known that the key etiologies of IBD include immune dysregulation, imbalances in the gut microbiota, and metabolic disruptions. Probiotics are now the potential treatment for IBD, due to their ability to regulate the host immune system and microbiota of the gut. Methods: The current study analytically tested the preventive benefit of Bacillus licheniformis BL-01 on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and also expounded on its molecular pathogenesis. Results: Our results demonstrate that supplementation with BL-01 effectively mitigates DSS-induced weight loss, an elevated disease activity index (DAI), and colonic tissue injury in mice. Concomitantly, BL-01 rectifies dysregulated inflammatory cytokine profiles, attenuates oxidative stress, and restores the expression of colonic tight junction proteins as well as the number of goblet cells. Furthermore, BL-01 modulates the gut microbiota diversity by increasing the abundance of beneficial bacterial genera such as Duncaniella and decreasing the abundance of pathogenic genera such as Helicobacter. Notably, BL-01 restores DSS-induced microbial metabolic dysregulation, modulates key metabolic pathways including arachidonic acid metabolism and steroid hormone biosynthesis, and regulates associated metabolites to ameliorate UC. Finally, Bacillus licheniformis BL-01 mitigates oxidative stress, reverses gut dysbiosis and metabolic disorders, and has a protective effect on UC. Conclusions: The findings give new information on the development of probiotic-based therapeutics in the prevention and treatment of IBD. Full article

Arbuscular mycorrhizal fungi (AMF) are widely applied as bioinoculants to enhance crop performance, yet their broader ecological effects on rhizosphere microbial assembly under field conditions remain insufficiently understood. Here, we evaluated the impact of a commercial AMF inoculant and its carrier material on lettuce performance and rhizosphere microbial communities in an open-field experiment. We hypothesized that both viable AMF propagules and formulation components contribute to shifts in rhizosphere processes. Active AMF inoculation significantly increased root colonization and fresh biomass at harvest, confirming successful establishment and enhanced plant performance under field conditions. Colonization levels in the heat-inactivated carrier treatment were comparable to the non-inoculated control, indicating that the carrier did not inhibit indigenous AMF activity or induce nutrient-mediated suppression of symbiosis. Plant physiological responses were stage-dependent, supporting the context-dependent nature of AMF effects in dynamic field environments. High-throughput sequencing revealed no significant treatment effects on bacterial or fungal alpha diversity. However, beta-diversity analyses demonstrated significant compositional restructuring of rhizosphere communities, particularly within the bacterial domain. A stable core microbiome persisted across treatments, yet relative abundances and community evenness were altered by both active inoculation and carrier application. These results suggest that AMF inoculation reorganizes microbial community structure predominantly via shifts in ecological niche occupation. Collectively, our results show that AMF inoculation functions not only as a symbiotic nutrient-acquisition strategy but also as a driver of rhizosphere microbial reorganization under field conditions. Integrating plant performance with microbiome dynamics provides a more comprehensive framework for understanding and optimizing microbial inoculants in sustainable agricultural systems. Full article

Modification of PLA with functional nanoparticles is a promising approach for imparting new properties to the material. In this work, titanium nanoparticles (Ti NPs) and titanium dioxide nanoparticles (TiO₂ NPs) were synthesized by laser ablation and characterized by dynamic light scattering, spectrophotometry, and transmission electron microscopy. The average hydrodynamic diameter of Ti NPs was 12 nm, while that of TiO₂ NPs was 24 nm; both dispersions possessed a positive zeta potential (23–27 mV) and spherical morphology. L-PLA composite films containing 0.1 wt.% Ti NPs or TiO₂ NPs were obtained by solution casting. Atomic force and modulation-interference microscopy confirmed the uniform distribution of nanoparticles within the polymer matrix, although partial aggregation was observed. The introduction of TiO₂ NPs increased the water contact angle. Mechanical testing revealed a significant reinforcing effect: the addition of 0.1 wt.% NPs increased the Young’s modulus by 62–68% and the ultimate tensile strength by 16–18% while maintaining a ductile fracture pattern with elongation at break up to ~8%. Both types of composites generated reactive oxygen species (ROS) in aqueous solutions: Ti NPs increased H₂O₂ production by 5.5 times and TiO₂ NPs by 4.9 times, and they also induced the formation of hydroxyl radicals. The accumulation of 8-oxoguanine in DNA and long-lived oxidized protein species confirmed the materials’ ability to cause oxidative damage to biomacromolecules. For E. coli, growth inhibition reached 40.5% (for composites with Ti NPs) and 71% (for composites with TiO₂ NPs). The effect was even more pronounced for S. aureus, where inhibition levels were approximately 70% and 80%, respectively; flow cytometry confirmed the strong bactericidal effect, showing that materials containing TiO₂ NPs increased the proportion of dead cells to 25% for E. coli and ~68% for S. aureus. Cytotoxicity assessment on human fibroblasts (HSF) demonstrated the high biocompatibility of neat L-PLA and composites with Ti NPs (viability > 95%) and with TiO₂ NPs (viability ~93%). The obtained results indicate that L-PLA-based composites with Ti NPs and TiO₂ NPs exhibit pronounced ROS-mediated antibacterial activity without additional UV irradiation. These findings position these materials as highly promising candidates for active biodegradable food packaging to extend shelf-life and for biomedical devices, such as wound dressings and implants, where reducing the risk of bacterial colonization is critical. Full article

Neonatal meningitis-associated Escherichia coli (NMEC) is a formidable pathogen in veterinary medicine. The emergence of atypical, multidrug-resistant (MDR) variants complicates disease control. An Escherichia coli (E. coli) strain was isolated from the brain tissue of a deceased calf with acute meningitis. Comprehensive characterizations were performed, including whole-genome sequencing (WGS), multi-locus sequence typing (MLST), antimicrobial susceptibility testing (AST), murine pathogenicity assays, and RT-qPCR evaluation of neuroinflammatory cytokines. Results: The isolate (O18ab:H14) was identified as a capsule-deficient NMEC strain belonging to phylogroup A and sequence type ST1434. WGS showed that the genome size of this strain is 5.1 Mb, containing 73 strictly defined antimicrobial resistance genes and 202 virulence factors. These may be involved in the compensatory mechanism for capsule deficiency, and further functional verification is required. Phenotypically, it exhibited a robust MDR profile. In the murine model, the strain demonstrated high lethality, and induced severe multi-organ lesions characteristic of both meningitis and systemic sepsis. While intraperitoneal injection bypasses natural colonization routes, the brain-specific bacterial persistence and neuronal pathology imply neurotropic potential. Furthermore, RT-qPCR confirmed a severe neuroinflammatory response, marked by the significant upregulation of IL-1β, IL-6, and TNF-α in the infected brains. This study characterizes a novel, highly virulent, and MDR capsule-deficient NMEC/SEPEC hybrid strain. The findings emphasize the urgent need for continuous genomic surveillance of atypical E. coli pathotypes in livestock. Full article

Titanium alloys are widely used in dental implants due to their excellent mechanical properties. However, their inertness and poor antibacterial activity cause interfacial loosening and failure, shortening service life. This study integrates surface microtexturing with coating technologies, employing modified light-curing composite resins to boost the bioactivity of medical titanium alloys via surface modification. The results reveal that surface microtexturing enlarges the coating-substrate contact area by 42.5% compared with rough surfaces, concurrently diminishing stress per unit area, and the coating on microtextured Ti-6Al-4V (TC4) surfaces achieves adhesion with a damaged area of only 0.5%, thereby notably enhancing adhesion between the coating and TC4 matrix. In comparison, with rough surfaces (surface roughness of 0.658 μm), smooth TC4 planes (surface roughness of 0.014 μm) show a significantly reduced bacterial colony count (from 130 ± 6 to 42 ± 3) with an antibacterial rate of 67.7%, as the water contact angle on TC4 surfaces increases with decreasing roughness (reaching 80.95° on the smoothest surface), making bacterial adhesion more challenging and reducing colonization. The composite resin coating based on a mixture of titanium-doped hydroxyapatite and titanium dioxide (Ti-HA/TiO₂) further improves the antibacterial rate to 74.6% through a photocatalytic synergistic effect and endows TC4 with excellent remineralization capacity—mineralization deposits appear on the coated surface after 3 days of immersion in artificial saliva, while no obvious deposits are found on uncoated rough and smooth surfaces even after 7 days—thereby enhancing its bioactivity effectively. This study on the modification of Ti-based implant surfaces will enrich the field by introducing new technologies and methodologies. These advancements provide a theoretical basis for improvement of the remineralization capacity and antibacterial properties of Ti-based dental implants, thereby promoting broader biomedical applications. Full article

Pseudomonas plecoglossicida causes bacterial hemorrhagic ascites in ayu (Plecoglossus altivelis), a lethal disease characterized by abdominal distension with hemorrhagic ascites, multifocal organ hemorrhages, and histopathologically evident hepatocellular necrosis and inflammatory infiltration. The lack of effective treatments exacerbates mass mortalities, posing a significant threat to aquaculture. Given the severe pathogenesis of P. plecoglossicida infection—which involves bacterial colonization, tissue necrosis, and host immune dysregulation—effective therapeutic strategies are urgently needed. Through a screen of traditional Chinese medicine monomers, we identified harmine, an indole alkaloid derived from Peganum harmala seeds, as a potent agent against this pathogen. In vivo, harmine exhibited direct bactericidal activity by disrupting membrane integrity, as evidenced by increasing membrane permeability, and inhibiting biofilm formation. In an ayu infection model, harmine significantly increased host survival, reduced tissue bacterial load, and enhanced innate immunity by augmenting monocyte/macrophage phagocytosis and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis. Mechanistically, the Drug Affinity Responsive Target Stability assay was used to identify the molecular target of harmine, followed by functional validation through PRDX6−knockdown experiments. Harmine exhibited direct bactericidal activity by disrupting membrane integrity and inhibiting biofilm formation. In the ayu infection model, harmine significantly increased host survival, reduced tissue bacteria1 load, and enhanced innate immunity by augmenting monocyte/macrophage system and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis, the latter likely through modulation of PRDX6−mediated oxidative stress and downstream caspase signaling. Mechanistically, DARTS revealed that harmine binds to peroxiredoxin 6 (PRDX6), a multifunctional enzyme possessing peroxidase, phospholipase A₂, and lysophosphatidylcholine acyltransferase activities. This binding liberates TNF receptor-associated factor 6 (TRAF6), facilitating its mitochondrial translocation and association with the ECSIT signaling integrator complex, thereby amplifying mitochondrial reactive oxygen species (mROS) production and potentiating macrophage-mediated bacterial killing. These findings establish harmine as a promising therapeutic candidate for controlling P. plecoglossicida infections and underscore the value of host-directed immunomodulation derived from natural products in aquaculture medicine. Full article

This study investigates the impact of inoculating seeds with bacterial endophytes isolated from Vitis amurensis Rupr. on endophytic community composition in Arabidopsis thaliana (L.) Heynh. Ten bacterial isolates of the genera Agrobacterium, Bacillus, Curtobacterium, Erwinia, Frondihabitans, Gordonia, Pantoea, Pseudomonas, Sphingomonas, and Xanthomonas were applied to seeds and some visible phenotypic effects were observed on plant growth after two weeks. High-throughput sequencing of 16S rRNA revealed that the native endophytic microbiome of A. thaliana was dominated by Gammaproteobacteria, Actinomycetes, Bacteroidia, and Alphaproteobacteria. The key families were Microscillaceae, Chitinophagaceae, Rhizobiaceae, Rhodanobacteraceae, Nocardioi-daceae, Nocardiaceae, Xanthomonadaceae, Devosiaceae, Microbacteriaceae, Crocinitomi-caceae, Pseudomonadaceae, Solimonadaceae, Comamonadaceae, Caulobacteraceae, and Micrococcaceae. Arabidopsis seed inoculation with Agrobacterium sp. R8SCh-B12, Curtobacterium sp. P7SA-B3, and Gordonia aichiensis P6PL2 significantly reduced alpha diversity (Shannon index) and altered beta diversity relative to controls, indicating strong community restructuring. These three isolates, along with Pseudomonas sp. R8SCh-B2, Sphingomonas sp. RA62c-B5, Xanthomonas sp. R7SCh-B6, and Bacillus velezensis AMR25, successfully colonized the plant tissues, as evidenced by significant increases in genus-specific amplicon sequence variants, ASVs (up to 17,820-fold for Curtobacterium sp. ASV33). In contrast, Pantoea sp. P7SCH-B5, Erwinia sp. R8SCh-B3, and Frondihabitans sp. RA62c-B2 failed to colonize A. thaliana, despite being applied to the seeds, suggesting the existence of mechanisms restraining colonization. These findings demonstrate that only a subset of grapevine-derived endophytes can effectively colonize A. thaliana, and that successful colonization correlates with significant shifts in the native microbiome, even in the absence of overt phenotypic changes. This emphasizes the importance of strain-specific compatibility in plant–endophyte interactions. Thus, we report the first descriptions of several novel endophytes that colonized Arabidopsis plants and establish a convenient model to investigate plant–bacterial interactions. Full article