This study presents the detailed characterization of Bacillus altitudinis B16 (= VTCC 910232) through phenotypic, genomic, and metabolomic analyses, highlighting its potential for aquaculture applications. Strain B16 exhibited a non-hemolytic profile, strong biofilm formation, moderate thermotolerance, growth across pH 5.0-9.0, tolerance to up to 10% NaCl, and susceptibility to most tested antibiotics. The extracellular ethyl acetate extract showed notable in vitro anti-Vibrio activity against five species (14.7-21.3 mm inhibition zones) and an anti-inflammatory effect in RAW 264.7 macrophages (IC50 = 33.9 µg/mL), with low cytotoxicity (> 91% viability). Metabolomic profiling tentatively identified 25 metabolites, predominantly bioactive diketopiperazines, together with putative anthramycin-like and mazethramycin-like compounds. Genome analysis (3.79 Mb; GC content 41.5%; 3,905 coding sequences; 73 transfer RNAs) revealed biosynthetic gene clusters for surfactin and bacilysin, likely involved in antimicrobial compound biosynthesis. B16 also harbored numerous genes involved in stress response and environmental adaptation, particularly those in transport systems and signal transduction pathways. No plasmid was confidently identified, and the genome harbored two genomic islands lacking virulence- or antibiotic resistance-associated genes. Collectively, the integrated phenotypic, metabolomic, and genomic analyses revealed the biosynthetic potential and adaptive traits of strain B16, including multiple putatively identified metabolites with reported bioactivities, suggesting its promise as a biocontrol agent for aquaculture.

We report a draft genome of Bacillus sp. isolated from deep-sea sediment from hydrothermal vents. The genome size is 4.20 Mbp with a %GC content of 43.41. Our results highlight genes related to biofilm, chemotaxis, antimicrobials, and multidrug resistance. The extensive secondary metabolite diversity supports the presence of microbial interactions.

The type VII secretion system (T7SS) is an ATPase-powered molecular machine encoded by Actinomycetota (T7SSa) and Bacillota (T7SSb) that exports small alpha-helical effectors with functions in interbacterial competition, host colonization, and virulence. While T7SSb has been well characterized in Staphylococcus aureus and Bacillus subtilis, its presence and function within the order Lactobacillales have only been thoroughly investigated within the past decade. Experimental evidence for T7SSb function has now been established in select Streptococcus and Enterococcus species. Here, we review the current understanding of T7SSb in these genera, covering core machinery and secreted substrates, including LXG toxins and WXG100 proteins. We discuss the roles of T7SSb during interbacterial antagonism and host-pathogen interactions, including contributions to cytotoxicity and virulence, as well as mucosal colonization and persistence. We further review known regulators of the T7SSb and evaluate the ecological significance of T7SSb-mediated competition for microbial community stability. Finally, we highlight outstanding questions in the field, including mechanisms of effector delivery, structural determination of the apparatus, impact of effectors on host immunity, and potential therapeutic targeting of T7SSb components.

Polyhydroxyalkanoate (PHA) synthase (PhaRCYB4) from Bacillus cereus YB-4 is a useful enzyme that produces PHA with various molecular weights depending on the host. The PhaRCYB4 mutant with an amino acid replacement of alanine at position 77 with serine in the PhaCYB4 subunit, which synthesized low-molecular-weight PHA, exhibited 2-fold higher polymerization activity than that of the wild-type enzyme.

The Gram-negative bacterium Dickeya solani causes potato soft rot and blackleg, and effective control measures remain limited. We evaluated the agricultural potential of Aspergillus sulphureoviridis, a recently described and chemically unexplored fungus. Bioactivity-guided molecular networking of extracts that inhibited D. solani led to the isolation of six metabolites: cladobotrin IV (1), two new analogs cladobotrin VII and cladobotrin VIII (2 and 3), and the orsellinic acid-derived metabolites F9775A (4), F9775B (5), and violaceol I (6). Among these, the polyketide F9775B (5) inhibited both Bacillus subtilis and D. solani (IC50 89.4 and 59.3 µg/mL, respectively), while cladobotrin VIII (3) was active against B. subtilis (IC50 95 µg/mL). Furthermore, co-culture with the beneficial rhizobacterium B. subtilis revealed an additional interaction: A. sulphureoviridis induced a pronounced antifungal defense in B. subtilis. MALDI-MSI showed that this interaction spatially enriched canonical Bacillus lipopeptides (surfactins and fengycins) at the confrontation zone, whereas the shortened fengycins variants were detected only intracellularly within the Bacillus colony. This indicates that A. sulphureoviridis triggers B. subtilis to mobilize and secrete bioactive lipopeptides for defense while retaining the less active short-chain fengycin-like compounds intracellularly. Together, these results establish A. sulphureoviridis as both a source of antimicrobial compounds and an inducer of beneficial bacterial defenses, providing a rationale for further in-planta validation and development as a sustainable biocontrol agent.IMPORTANCEPotato soft rot and blackleg caused by Dickeya solani are difficult to control, creating a need for sustainable biocontrol strategies. Here, we show that the recently described fungus Aspergillus sulphureoviridis has a dual function relevant to crop protection. Bioactivity-guided molecular networking enabled the targeted discovery of six antibacterial metabolites, including two new cladobotrin analogs and the first cladobotrins reported from Aspergillus, and identified F9775B as the main metabolite active against D. solani. Using MALDI mass spectrometry imaging, we further demonstrate that A. sulphureoviridis does not act only through its own metabolites but also triggers Bacillus subtilis to enrich and deploy surfactin and fengycins at the interaction zone. These findings expand the known chemical diversity of A. sulphureoviridis and support its potential as a dual-function contributor to sustainable microbe-based biocontrol.

Chemical signaling between soil inhabitants is of tremendous importance to the health of many ecosystems, and at the same time detailed molecular knowledge underlying these conversations is surprisingly scarce. One of the major bacterial genera inhabiting the rhizosphere is Pseudomonas, of which most species are known to produce phenazines, which carry antibiotic properties. Pseudomonas chlororaphis, a common rhizosphere dwelling species with plant growth-promoting traits, produces phenazine-1-carboxamide (PCN). This study examines how the production of PCN by Pseudomonas affects another common species in soil that it often encounters, namely Bacillus subtilis. When both species were cultured at close distance, distinct and visible changes in colony morphologies were observed without changes in growth rates. Interestingly, a clear transformation occurred in the morphology of B. subtilis colonies in the presence of supplemented PCN, indicating the role of phenazines in affecting colony morphology. In addition, untargeted metabolomics analyses showed a decrease in the production of plipastatin and surfactin by B. subtilis in the presence of P. chlororaphis. Our results indicate that PCN induces changes in morphology and signaling of B. subtilis without significantly affecting its growth. We hypothesize that P. chlororaphis and B. subtilis sense one another and act to conserve energy while avoiding competition.

Mannan oligosaccharides (MOS) are valuable prebiotics, and enzymatic hydrolysis by β-mannanase is the preferred production route. Bacillus-derived GH26 β-mannanase (gmuG) holds industrial promise but suffers from low catalytic efficiency and weak pH stability. Here, we rationally engineered flexible loops near the active site via molecular dynamics, NMsim (normal mode-based geometric simulation), sequence conservation analysis, and MAESTRO prediction, and obtained the optimal double mutant M1 (E301K-T271V). Relative to the wild type, M1 showed 1.54-fold higher specific activity and nearly 2-fold improved pH stability at pH 8, with a nearly doubled kcat while retaining substrate affinity. Mechanistically, M1 enlarged the active site, shortened the attack distance of the catalytic residue, increased α-helix content, and rigidified neighboring loops. Fermentation optimization in Escherichia coli gave a maximum yield of 924.34 U/mL. This work offers an effective strategy for β-mannanase engineering and a high-performance biocatalyst for industrial MOS production.

The tomato leafminer, Tuta absoluta, poses a severe threat to tomato production in China, yet regional resistance patterns remain poorly characterized. This study investigates the insecticide resistance status and underlying molecular mechanisms in field populations of T. absoluta across major tomato-producing regions in China. Ten populations were evaluated for susceptibility to seven commonly used insecticides using standardized bioassays, alongside screening for resistance-associated target-site mutations in key genes. The results indicate that most populations remain susceptible to spinetoram, abamectin, and indoxacarb, supporting their continued effectiveness in field control. However, moderate resistance to emamectin benzoate was detected in several populations, with resistance ratios reaching up to 75.09 fold. Additionally, low to moderate resistance to Bacillus thuringiensis (Bt) and broflanilide was observed in certain regions. Although resistance ratios to bifenthrin were relatively low, consistently high LC50 values suggest a widespread reduction in baseline susceptibility. Molecular analyses revealed that the L1014F mutation in the voltage-gated sodium channel (VGSC) gene was fixed across all populations, while M918T and T929I mutations occurred at high frequencies. Notably, no significant correlation was found between these mutations and phenotypic resistance levels, and no resistance-associated mutations were detected in the nAChR gene. These findings highlight the complex and potentially multifactorial nature of resistance in Chinese T. absoluta populations and provide important guidance for optimizing insecticide rotation and resistance management strategies.

In the current industrial scenario, chromium (Cr) and lead (Pb) contamination poses a serious threat to agricultural ecosystems due to their toxic effects on plant growth and productivity. However, limited studies have explored the role of plant growth-promoting rhizobacteria (PGPR) in alleviating combined Cr and Pb stress in rice. Therefore, the present study investigated the potential of Pseudomonas putida, Bacillus amyloliquefaciens, and Pseudomonas fluorescens in mitigating metal-induced toxicity in rice (Oryza sativa L.) under different Cr and Pb levels [0 (without Cr and Pb stress), 100 and 200 mg kg[-][1])]. The research outcomes indicated that elevated levels of Cr and Pb stress in the soil significantly (P ≤ 0.05) decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics, while increasing oxidative stress biomarkers including malondialdehyde (MDA) and hydrogen peroxide (H2O2). Metal toxicity also altered antioxidant defense systems, sugar accumulation, proline metabolism, and the ascorbate-glutathione (AsA-GSH) cycle. However, the application of P. putida, B. amyloliquefaciens, and P. fluorescens significantly improved morphophysiological and biochemical attributes, enhanced antioxidant defense and related gene expression, reduced oxidative damage, and decreased Cr and Pb accumulation in plant tissues. Furthermore, PGPR application improved cellular fractionation and regulated stress-responsive metabolic pathways in O. sativa under metal-stressed conditions. Overall, the findings highlight the significant potential of these PGPR strains as sustainable biological agents for improving metal stress tolerance and physiological performance in O. sativa plants grown under Cr and Pb toxicity.

A valuable and sustainable residue derived from the distillation of Rosa damascena petals contains esters, diols, and hydroxyl compounds. Anbar (in Iranian culture, the highly aromatic compound is called Anbar.) was investigated for the first time through encapsulation into a tosylated β-cyclodextrin (βCD-Ts) inclusion complex. The βCD-Ts was synthesized via solvent and ball-milling methods and complexed with Anbar. Key components including lauric, oxalic, decanoic, formic and cyclopentadecanoic acids, ethyl propanoate and nitrogen-containing species were identified. The identification and systematic peak shifts of C = O stretching and aromatic C = C broadening confirmed the presence of hydrogen bonding, π-π and van der Waals interactions. A new and distinct crystalline phase (at 2θ 33 °C) was identified that was not present in either component. Thermal changes from about 360 °C (Anbar) to about 275 °C (complex) with about 99.2% mass loss confirmed encapsulation. The complex exhibited polarity-dependent solubility with water as the optimal solvent. A βCD-Ts to Anbar ratio of 5:1 yielded EE% of 64.9% +/- 2.81% and LC% of 11.51% +/- 0.82%. Particle size of Anbar was detected in the range of 63-288 nm. Antibacterial test was performed for 2 bacterial strains, Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative). The βCD-Ts-Anbar showed significantly larger inhibition zones against Bacillus subtilis compared to Escherichia coli. Overall, βCD-Ts-Anbar may have biomedical and industrial applications.

The RING finger E3 ligase group is a broadly distributed subfamily of E3 ubiquitin ligases characterized by the presence of a RING domain and is involved in various immunological responses. In this study, Ring finger protein 181 (RNF181) in Bombyx mori (B. mori) was identified and investigated its immunoregulatory function. The BmRNF181 gene is located on chromosome 6 and contains an open reading frame of 441 base pairs, encoding a protein consisting of 146 amino acids. The predicted molecular weight is 16.71 kDa, with a the theoretical isoelectric point of 6.50. The encoded protein possesses a characteristic RING domain and seven predicted phosphorylation sites. The recombinant protein was successfully expressed and purified using the pET-28a-BmRNF181 construct. Quantitative real-time PCR (qRT-PCR) analysis revealed that BmRNF181 was expressed in all examined tissues, with the highest level in the fat body and the lowest in the Malpighian tubules. Developmental expression profiling showed that the highest expression level occurs at the fifth instar larval stage. Following challenge with four different pathogens (Escherichia coli (E. coli), Beauveria bassiana (B. bassiana), Bacillus thuringiensis (B. thuringiensis), and B. mori nuclear polyhedrosis virus (BmNPV)). BmRNF181 expression in the fat body was significantly upregulated. Moreover, RNA interference-mediated knockdown of BmRNF181 dramatically increased the expression of antimicrobial peptide genes. These findings suggest that BmRNF181 acts as a negative regulator of the silkworm immune response.

Fusarium solani root rot of tomatoes causes severe production losses, and the development of safe biological management strategies is an urgent core industry need. In this study, the research material of the endophytic bacteria Bacillus endophyticus was used, and the research work was carried out in the following sequence of tests for the core aims of managing this disease and investigating its application value: Firstly, the antagonistic activity of the strain against Fusarium solani was tested by in vitro dual culture assay, and the mycelial growth inhibition rate was up to 68.2%. The strain was also shown to possess three plant growth-promoting features, including synthesis of the auxin indole-3-acetic acid (IAA), phosphorus solubilization, and cellulase production. In this work, a greenhouse experiment was conducted to confirm the effectiveness of the target biocontrol strain in controlling the disease. The test results showed the germination rate of damaged seeds in the treatment group was 88%, far higher than the 57% of the infected control group. The disease severity in plants decreased from 59.7% in the control to 18.3%, and the total biocontrol efficiency reached 69.3%. The treatment group showed a considerable rise in the activity of defense enzymes, suggesting that this strain has great potential for use in the field. These findings evidence the ability of B. endophyticus to enhance tomato growth and control root rot, induced by F. solani, suggesting its potential as a biocontrol agent towards sustainable production of tomatoes in an environmentally safe way.

Mycobacterium marinum is a slow-growing nontuberculous mycobacterium, most commonly causing cutaneous infection after prolonged or repeated exposure to contaminated aquatic environments. Diagnosis is frequently delayed because of its indolent course, nonspecific clinical features, and frequent misattribution to more common dermatologic conditions. We report the case of a 51-year-old immunocompromised woman who developed a progressive ulcerative lesion on the right wrist after a presumed spider bite following a farm visit. Despite multiple emergency department encounters and empiric antibacterial therapy, the lesion failed to improve. Acid-fast bacilli culture from a wound specimen ultimately grew M. marinum several weeks after initial presentation. Subsequent history revealed a previously undisclosed history of exposure to a home aquarium. Management was complicated by impaired oral antimicrobial absorption following prior bariatric surgery and incomplete clinical response to initial therapy, necessitating prolonged outpatient parenteral antimicrobial treatment, with eventual clinical resolution. This case underscores the impact of diagnostic anchoring bias, highlights the importance of thorough environmental exposure assessment beyond classic aquatic settings, and emphasizes early consideration of nontuberculous mycobacterial infection in chronic, nonhealing cutaneous lesions.