Search Results (1,525)

Microbial biocontrol agents often exhibit limited shelf life, which restricts their commercialization, storage, and large-scale agricultural application. In this study, freeze-drying (FD) microencapsulation was evaluated as a strategy to improve the stability of a wettable powder (WP) formulation based on Bacillus subtilis fermented broth using maltodextrin (MD) as a carrier. The physicochemical, structural, morphological, and antifungal properties of the resulting formulation were characterized. Physical characterization revealed complete solubility (100% at 0.1 g mL⁻¹), rapid wettability (2 s), and low hygroscopicity (3.86%), indicating favorable properties for handling and application. Scanning electron microscopy revealed irregular glass-like particles of different sizes, while Fourier transform infrared spectroscopy indicated the distribution of components within the maltodextrin matrix. The antifungal activity of the WP and the effects of its volatile organic compounds (VOCs) were evaluated against the phytopathogenic fungi Fusarium oxysporum, Fusarium solani, Fusarium graminearum, Rhizoctonia solani, and Sclerotinia sclerotiorum. The formulation inhibited fungal growth within the tested concentration range (0.1–0.2 g mL⁻¹), although no clear inhibition zone was observed for S. sclerotiorum. Furthermore, the WP maintained 65% viability after 24 months of storage at 4 °C. These results demonstrate the potential of FD microencapsulation to enhance the storage stability of Bacillus subtilis formulations while preserving their antifungal activity. Full article

Large-scale production of Bacillus thuringiensis, one of the most widely used biopesticides, is often limited by the high cost of conventional culture media. In this study, fermented cassava paste water (EFM), ripe mango pulp juice (CM), and cashew apple juice (JPC) were evaluated as alternative substrates for the liquid fermentation of B. thuringiensis var. kurstaki HD-1. Physicochemical analyses revealed acidic pH values and classified the substrates into two clusters: CM with high C/N ratios, organic matter, total sugars, and proteins, and EFM and JPC with lower C/N ratios and nutrient levels. Fermentation results indicated that JPC supported the highest biomass production (8.29 × 10¹³ CFU mL⁻¹), exceeding that in the standard Tryptone Soy Broth (TSB) medium. However, CM promoted the highest sporulation rate (1.46 × 10¹³ CFU mL⁻¹) and the greatest bioactive lipopeptides—iturins (102.2 mg L⁻¹) and surfactins (554.7 mg L⁻¹)—surpassing TSB. The antifungal activity of crude fermented CM, EFM, and TSB was evaluated against Sclerotium rolfsii. All samples significantly inhibited mycelial growth of the pathogen with no significant differences among substrates or concentrations tested. This study highlights the potential of B. thuringiensis-fermented agrowaste as a cost-effective, environmentally friendly biocontrol tool for Sclerotium rolfsii. Full article

Nutgall tree anthracnose, caused primarily by Colletotrichum species, acts as a primary bottleneck restricting the sustainable development of the Rhus chinensis industry. Developing green biocontrol strategies by screening molecular targets for novel fungicides is highly imperative. A strain designated as Serratia plymuthica WF63 was isolated from healthy R. chinensis tissues. The strain exhibited broad-spectrum antifungal activity and multiple plant growth-promoting (PGP) traits, including the production of protease, cellulase, and indole-3-acetic acid (IAA). In vivo experiments revealed that S. plymuthica strain WF63 achieved a biocontrol efficacy of over 50% against anthracnose pathogens (Colletotrichum nymphaeae and C. fioriniae) and demonstrated significant plant growth-promoting effects. Gas chromatography–mass spectrometry (GC-MS) analysis, combined with in vitro toxicity validation of pure compounds, identified hexahydro-2H-pyrido [1,2-a]pyrazin-3(4H)-one as a core antifungal component in the fermentation broth, with a half maximal effective concentration $\left(E{C}_{50}\right)$ of 133.88 mg·L⁻¹ against the target pathogen. These findings not only highlight S. plymuthica strain WF63 as a promising antifungal biological agent but also suggest that the specific nitrogen-containing heterocyclic compound may serve as a candidate scaffold for further fungicide optimization, pending comprehensive ecotoxicological evaluation. Full article

To identify novel field control strategies against Pyrrhalta aenescens (Coleoptera: Chrysomelidae) and provide scientific support for its biocontrol in urban tree management, this study investigated the virulence of Beauveria bassiana against this pest under laboratory conditions, as well as its physiological and biochemical effects. Bioassays using the dipping method showed that B. bassiana was pathogenic to all developmental stages of P. aenescens, with the highest virulence observed against early-instar larvae (1st and 2nd instars). For these stages, corrected mortality and mycosis rate were positively correlated with conidial concentration, and the median lethal time (LT₅₀) was the shortest. In contrast, pupae and eggs exhibited the strongest resistance to fungal infection. In leaf-disk choice tests, larvae significantly preferred untreated leaves or those treated with low concentrations of B. bassiana, displaying a concentration-dependent repellent response to the fungus. Physiological measurements revealed that larval body length and weight gain were significantly inhibited following fungal exposure. Further analysis indicated that B. bassiana infection markedly reduced total hemocyte counts and triggered intense melanization and nodulation responses, particularly in younger larvae. Overall, these results suggest that B. bassiana has strong potential for the biological control of P. aenescens. Control measures targeting early-instar larvae are recommended for cost-effective management, providing a scientific basis for developing eco-friendly control technologies based on this entomopathogenic fungus. Full article

Botrytis cinerea is a major phytopathogenic fungus responsible for substantial economic losses in horticultural crops, underscoring the need for sustainable alternatives to synthetic fungicides. This study investigated the influence of physical, chemical and biological culture parameters on the antifungal activity of culture filtrates produced by Trichoderma harzianum BOL-12QD. Culture conditions were sequentially optimised by evaluating light-filter exposure, carbon and nitrogen source composition, potato ecotype selection, co-cultivation with Botrytis cinerea, and volatile-mediated interactions. Antifungal activity was assessed using mycelial growth inhibition assays against Botrytis cinerea. Among the individual factors, violet-filter illumination, a medium containing 5 g L⁻¹ glucose and 250 g L⁻¹ potato extract, the Leke Pek’e potato ecotype, ammonium nitrate as nitrogen source, and co-cultivation with Botrytis cinerea at 10⁴ conidia mL⁻¹ produced the highest inhibitory effects. Sequential integration of these optimised conditions resulted in enhanced antifungal activity, reaching up to 62% inhibition. Volatile organic compounds produced by Trichoderma harzianum BOL-12QD exhibited only minimal antifungal activity under the conditions tested, suggesting that volatile-mediated antagonism plays a limited role in this system. In contrast, culture-dependent modulation of extracellular metabolite profiles was evidenced by comparative ¹H NMR fingerprinting, which revealed condition-specific spectral differences, with the optimised treatment displaying a distinct metabolic signature relative to all other conditions. Cytotoxicity assays in murine peritoneal macrophages showed no significant reduction in cell viability at concentrations up to 200 μg mL⁻¹. In vivo exposure to the optimised culture filtrate (250 mg kg⁻¹ d⁻¹ for 10 days) induced transient treatment-related clinical observations without mortality, indicating a need for further detailed toxicological characterisation. Overall, these findings demonstrate that the antifungal activity of Trichoderma harzianum BOL-12QD is strongly modulated by interacting environmental, nutritional and biological culture parameters. The results support the potential of optimised culture filtrates as a source of bioactive metabolites for biocontrol applications, while highlighting the importance of integrated biochemical and toxicological evaluation. Full article

Chemical agents have long been used to control plant diseases, but their effects on the environment and lack of alignment with sustainable development goals are making them gradually unsuitable. One trend in green agriculture is the use of Bacillus species for the biocontrol of plant diseases. Due to their vast metabolic and genetic diversity, Bacillus spp. can contribute significantly to the soil ecosystem, while also enhancing plant resilience to biotic and abiotic stresses. Bacillus spp. are widely used in the agrobiotech industry due to their multi-functional versatility and are well-known for protecting plants from numerous plant diseases. In this review, we discussed the diversity and functions of antimicrobial compounds (AMCs) produced by Bacillus spp., along with their roles in plant growth promotion (PGP), and immunity. Furthermore, we highlighted the potential of Bacillus spp. as biopesticides in host plants, ways to enhance their biocontrol efficacy, and also addressed their possibility to cause disease in host plants. Considering the beneficial impacts of Bacillus spp. on PGP and pathogen biocontrol and their disease-causing capability, we discussed the possible solutions for a safe development of Bacillus-based biocontrol agent (BCA). Collectively, these insights can guide the selection of Bacillus strains with broad-spectrum or target-specific activity against pathogens, ensuring minimal adverse effects on the host. Full article

Lactic acid bacteria (LAB) have been widely utilized in the production of fermented foods worldwide due to their well-established health-promoting benefits for both humans and animals. In addition to their nutritional value, LAB exhibit antagonistic activity against foodborne pathogens, particularly Salmonella spp., which are commonly associated with livestock and animal production systems. LAB exert a range of biological effects that can inhibit the growth of Salmonella and modulate its virulence. In the present study, the antagonistic potential of Weissella confusa WM36 was evaluated based on its ability to inhibit S. Typhimurium growth, disrupt biofilm formation, and suppress the expression of virulence-associated genes. A preliminary safety assessment of W. confusa WM36 was conducted through hemolytic activity and antibiotic susceptibility profiling. In addition, the biofunctional properties of its cell-free supernatant (CFS), herein referred to as postbiotic metabolites, were investigated with a particular focus on antioxidant activity. Experimental results demonstrated that W. confusa WM36 and its CFS at 40% (v/v) achieved a complete reduction (100%) of S. Typhimurium cell counts within 6 to 12 h of treatment. Furthermore, CFS at 20% and 40% (v/v) significantly impaired biofilm formation, while treatment with 20% (v/v) CFS markedly downregulated the expression of key virulence genes. The strain WM36 exhibited α-hemolytic activity and showed susceptibility to most of the antibiotics tested, although resistance to ceftriaxone and trimethoprim–sulfamethoxazole was observed. These findings provide preliminary information regarding its safety characteristics; however, further molecular and in vivo investigations are required to comprehensively evaluate its safety for practical applications. Additionally, the CFS exhibited notable antioxidant activity, with DPPH radical scavenging capacity of 8.90 ± 0.06 mM Trolox equivalents and ABTS radical scavenging power of 13.10 ± 1.42 mM Trolox equivalents. Collectively, these findings highlight the potential of W. confusa WM36 and its postbiotic metabolites as promising biocontrol and functional agents against S. Typhimurium, while further safety validation remains necessary. Full article

Root-knot nematodes (Meloidogyne javanica and M. incognita) constrain olive (Olea europaea L.) production and require safer alternatives to chemical nematicides. Despite the growing interest in microbial biocontrol agents, limited information is available on how application timing and microbial consortia influence nematode suppression and host biochemical responses in olive. This greenhouse study evaluated endophytic Trichoderma (T. harzianum) and Bacillus (B. subtilis), applied alone or in combination, either before or after nematode inoculation, to determine how biocontrol treatment timing influences nematode suppression, plant performance, and host biochemical responses. Across both nematode species, preventive application consistently outperformed curative application, and the combined treatment delivered the strongest overall protection. Preventive co-application reduced nematode infection, improved root and shoot growth, attenuated oxidative damage, and preserved chlorophyll more effectively than single-agent or post-inoculation treatments. Spectroscopic (Fourier Transform Infrared (FTIR)) and multivariate analyses further showed that effective treatments were associated with lower nematode-associated protein and lipid signals and stronger signatures of structural defense in root tissues. Although M. javanica caused greater physiological disruption than M. incognita, both species responded to the same general treatment pattern. These findings show that early establishment of microbial biocontrol agents is critical for durable suppression of root-knot nematodes in olive and supports preventive microbial consortia as a promising strategy for integrated nematode management. Full article

This study explores the use of endophytic fungi for the biocontrol of harmful aflatoxins (AFTs) in maize (Zea mays L.). The main objective of this study was to evaluate the effects of fungal pathogens and biocontrol agents on the corn seed germination and growth of seedlings under controlled conditions. Experiments were conducted under laboratory conditions in a growth chamber and in a greenhouse to assess the influence of environmental factors on seed performance and treatment efficacy. The growth chamber provided uniform conditions for physiological assessment while the greenhouses represented more realistic field conditions. Corn kernels were sown in sterile pots inside the growth chamber at standard conditions or in the greenhouse at controlled conditions and four treatment groups were established: untreated control seeds, seeds treated with non-AFT-producing (non-aflatoxigenic) strains (Trichoderma harzianum, T. asperellum and Aspergillus niger), seeds inoculated with AFT-producing (aflatoxigenic) strains (A. flavus and A. parasiticus), and seeds co-inoculated with both aflatoxigenic and non-aflatoxigenic strains (A. flavus and A. parasiticus with T. harzianum, T. asperellum or A. niger). High-performance liquid chromatography was utilized to detect and analyze the presence of AFTs. Co-culturing of A. flavus with T. harzianum resulted in a significant decrease in AFT levels, achieving a relative reduction of 99.3% compared to aflatoxigenic treatments alone. Among the isolates tested, T. harzianum and T. asperellum were the most effective at lowering AFT production of the aflatoxigenic strains, reducing the 5120 ± 560 µg/kg AFT level produced by A. flavus alone to 50.1 ± 1.10 and 63.1 ± 3.1 µg/kg, respectively. A. flavus negatively affected germination and early growth, whereas T. harzianum significantly enhanced both parameters. This study demonstrates that non-aflatoxigenic Trichoderma isolates can effectively mitigate AFT contamination and improve seedling growth, highlighting their potential as effective. sustainable, and locally adopted biocontrol agents for Pakistan’s chronic AFT problem under diverse environmental conditions—an area with minimal prior research and high national relevance. Full article

Massilia varians has potential as a probiotic to inhibit bacterial pathogens in aquaculture, but very limited information is available regarding its use in Chinese mitten crab Eriocheir sinensis for enhancing host immunity, antioxidant ability and intestinal microbiota homeostasis. In this study, a 40-day feeding trial was conducted to evaluate the protective effects of dietary supplementation with M. varians P2-4 on nonspecific immune response, antioxidant status, intestinal microbiota and resistance against Pseudomonas aeruginosa infection in E. sinensis. Results demonstrated that dietary supplementation with M. varians P2-4 at 6.0 × 10⁶ to 6.0 × 10⁸ CFU/g diet significantly boosted nonspecific immunity and improved antioxidant capability of E. sinensis, mainly as evidenced by markedly increased activities of plasma lysozyme, plasma superoxide dismutase, hepatopancreatic superoxide dismutase and catalase. Furthermore, crabs fed M. varians P2-4-supplemented diets exhibited markedly improvements in intestinal microbiota composition and diversity, and showed substantially enhanced survival following P. aeruginosa challenge, with 7-day relative percentage survival ranging from 76.9% to 100.0%. To the best of our knowledge, this is the first study to reveal that M. varians P2-4 supplementation functions as a new biocontrol strategy in E. sinensis by effectively improving the non-specific immunity, antioxidant status and intestinal microbiota to mitigate P. aeruginosa infection. Full article

Ornamental fountains in the Alhambra and Generalife (Granada, Spain) constitute complex socio-ecological systems where water, stone, and biological communities interact, making them highly vulnerable to biodeterioration caused by phototrophic microorganisms such as cyanobacteria, green algae, and diatoms. Conventional chemical biocides, although widely applied, present significant drawbacks including toxicity, material degradation, ecological imbalance, and limited long-term effectiveness. In this context, this study evaluated the potential of algicidal bacteria as a sustainable alternative for controlling phototrophic growth in heritage environments. Water samples from eight ornamental fountains were analyzed using 16S ribosomal RNA (16S rRNA) gene sequencing to characterize bacterial communities and identify taxa previously reported with algicidal activity. Statistical analyses were conducted to assess relationships between microbial community structure and biofilm development. In parallel, functional screening assays using filtered fountain waters against Chlorella vulgaris were performed to evaluate intrinsic inhibitory capacity. The most active sample was selected for bacterial isolation and further validation through co-culture assays, cell density measurements, and pulse-amplitude-modulated (PAM) fluorometry. A total of 18 genera with reported algicidal capacity were detected, representing a substantial fraction of the microbiome across all samples. However, no significant association was found between these taxonomic metrics and biofilm development, highlighting a decoupling between taxonomic composition and functional activity. The most active isolate, identified as Stenotrophomonas maltophilia strain LIG25, caused a rapid decline in photosynthetic efficiency and achieved more than 98% inhibition of algal growth. These findings demonstrate that ornamental fountain microbiomes represent a reservoir of native biocontrol agents and support the development of eco-friendly strategies for cultural heritage conservation. Full article

Tomato is susceptible to various fungal pathogens, including Alternaria alternata and Curvularia spicifera, which can cause extensive post-harvest losses. Chemical fungicides have limited effectiveness in controlling post-harvest fungal pathogens and pose risk to human health and the environment. Therefore, this study assessed indigenous isolates of three species of Trichoderma (Tr1: T. longibrachiatum; Tr2: T. harzianum; and Tr3: T. asperellum) as biocontrol agents against two fungal pathogens in vitro and in vivo and determined their physicochemical analysis and plant-growth-promoting traits. The three species of Trichoderma exhibited catalase production in vitro, while T. longibrachiatum and T. asperellum showed the highest potential for plant-growth promotion by producing indole-3-acetic acid and phosphate solubilization but not nitrogen-fixing capability. T. harzianum showed lower potential in these traits. Mycelial growth was found to be maximum (5.77–12.27 cm) at 30 °C and a pH of 7–9, but inhibition (2.60–5.13 cm) was recorded at the highest temperature (45 °C) and pH (11). In vivo, studies on tomato fruits indicated that T. longibrachiatum and T. asperellum significantly (p < 0.05) reduced lesion diameters of A. alternata by 53.60% and 48.71%, respectively, and C. spicifera by 55.58% and 56.19%, respectively, relative to the infected control. Besides their antifungal efficacy, the three species of Trichoderma enhanced tomato seedling growth, particularly at 1/10 filtrate dilution, and improved fruit quality parameters by increasing firmness and nitrate content, while reducing oxidative stress. Physicochemical analysis indicated that Trichoderma-treated fruits had better firmness, pH, and nitrate value coupled with a reduction in oxidative stress (reduced malondialdehyde content) compared to pathogen-infected controls. The indigenous isolates of the three species of Trichoderma provided high efficacy as biocontrol agents of the two fungal pathogens that cause post-harvest losses of tomato, suggesting that biological control can replace synthetic chemicals in preserving tomato under storage conditions and contribute to agricultural sustainability. Full article

Bretziella fagacearum (formerly Ceratocystis fagacearum (Bretz)) Hunt is a vascular pathogen responsible for oak wilt disease, which affects various oak species in North America. Once established, management options include root disruption, removal of infected wood, and fungicide application, each with variable efficacy. This is the first study to assess three commercial biofertilizers against B. fagacearum in vitro, using Spectrum supplemented with Pepzyme Clear (SPC), EM-1, and Power Gelatinase and Chitinase-producing Microorganism (PGCM), as no biological methods currently exist. These biofertilizers were chosen for microbes associated with improved nutrient uptake and for their potential biocontrol activity. We conducted dual-culture plate assays, volatile organic compounds (VOCs) assays, and non-volatile metabolite assays. EM-1 and PGCM exhibited the strongest antagonistic effects for dual-culture plate assays (56% and 68%, respectively) and for VOCs assays (62% and 47%, respectively). After 15 days of exposure to non-volatile metabolites, microscopic analysis revealed severe hyphal distortions from EM-1 and PGCM. These preliminary in vitro findings suggest that PGCM and EM-1 suppressed mycelial growth of B. fagacearum and may be used as biological control. Further field studies are needed to understand how environmental factors and soil–tree–microbe interactions can affect their efficacy against oak wilt disease. Full article

The β-1,3-glucanase gene family plays an important role in fungal cell wall degradation and is closely associated with the mycoparasitic interactions of biocontrol fungi. In this study, the β-1,3-glucanase gene family was identified in the mycoparasitic Alternaria alternata strain KMR13, and its expression patterns under Podosphaera pannosa spore induction were analyzed to investigate the role of the gene Aag25 in the degradation of P. pannosa spores. The β-1,3-glucanase gene was extracted from the genome using the bioinformatics method. According to the expression level of spore-induced genes of P. pannosa, the GH17 family genes that may be involved in mycoparasitism were screened, cloned, and expressed. The expressed protein was purified, and its activity and ability to destroy spores of P. pannosa were determined. A total of 30 β-1,3-glucanase genes were identified in strain KMR13, including 18 members of the GH16 family, 8 of the GH17 family, and 2 genes each from the GH64 and GH81 families. Transcriptome analysis revealed that 23 of these genes were expressed under spore induction. Based on differential expression analysis, the β-1,3-glucanase gene Aag25 was selected for prokaryotic expression. The recombinant Aag25 protein (~32.08 kDa) was successfully induced and purified, exhibiting an enzymatic activity of 1.464 U/mg protein. Functional assays demonstrated that recombinant Aag25 could effectively disrupt the cell walls of P. pannosa spores, leading to spore rupture and cytoplasmic leakage. These results indicate that Aag25 plays an important role in fungal cell wall degradation during the mycoparasitic process of strain KMR13 and provides a potential enzymatic resource for the development of biological control strategies targeting fungal pathogens. Full article

Fusarium oxysporum f. sp. lycopersici is one of the most destructive soilborne pathogens affecting tomato production, reducing plant growth and yield and highlighting the need for sustainable management alternatives. Streptomyces spp. are promising microbial candidates due to their ability to combine antifungal activity with plant growth promotion characteristics. The objective of this study was to evaluate the biofertilizer and antifungal potential of Streptomyces spp. in Chonto tomato (Solanum lycopersicum Mill.) under greenhouse conditions. Seventy actinobacterial strains were screened in vitro against F. oxysporum, and eight exhibited significant antagonistic activity. Based on antagonistic activity, enzymatic profile, cytotoxicity, and plant growth-promoting potential, strains 1B260 and 445 were selected for greenhouse assays. Strain 1B260 achieved 43.5% mycelial growth inhibition and showed the highest phosphate-solubilizing capacity (420 µg/mL), while both strains displayed proteolytic and cellulolytic activity, low cytotoxicity in human skin cell lines (HaCaT and HDFa), nitrogen fixation, and ammonia production. In greenhouse assays under non-infected conditions, 1B260 showed the most consistent biofertilizer effect, promoting stem elongation. Under pathogen pressure, strain 445 improved plant performance compared to the infected control. Overall, strains 1B260 and 445 exhibited complementary roles in tomato crop management, highlighting the potential of multifunctional Streptomyces inoculants for sustainable biofertilization and biocontrol strategies. Full article