Archives of Microbiology最新文献

Camellia oleifera and Elaeocarpus decipiens are significant economic crops in South China. However, their production is severely impacted by diseases caused by Colletotrichum gloeosporioides or Pseudocryphonectria elaeocarpicola, respectively. The phyllosphere microbiota of diseased plants represents an underexplored reservoir of functional microorganisms with bioactive potential. However, no prior studies have investigated antagonistic microorganisms from these communities against both pathogens. In this study, 45 fungal strains were isolated from six species of diseased plants in southern China. Their ability to produce secondary metabolites was evaluated using high-performance liquid chromatography (HPLC), leading to the selection of 20 strains with complex and unique chromatographic profiles as bioactive candidates. Dual-culture assays revealed that nine strains exhibited significant antagonism against C. gloeosporioides, producing extracellular antifungal metabolites with maximum antagonistic index of 218.64 ± 26.36% and inhibition rate of 57.92 ± 0.77%. Eight strains showed marked antagonistic activity against P. elaeocarpicola, also secreting antifungal compounds, with maximum antagonistic index of 106.66 ± 16.83 and inhibition rate of 74.99 ± 0.23%. Notably, strains DP13, DP14, and DP16 strongly inhibited both pathogens. Phylogenetic analysis identified the nine highly antagonistic strains as Diaporthe sp. (DP13), Chaetomium globosum (DP14), Muyocopron dipterocarpi (DP15), Muyocopron lithocarpi (DP16), Fusarium equiseti (DP20), Neopestalotiopsis sp. (DP28), Fusarium lateritium (DP32, DP33), and Diaporthe heliconiae (DP43). This study provides insights into exploring functional microorganisms from diseased phyllosphere microbiota and offers valuable resources for eco-friendly management of camellia anthracnose and Elaeocarpus blight, with DP13, DP14, and DP16 as promising broad-spectrum biocontrol candidates.

Fungal activity significantly contributes to the turnover of minerals and other nutrients in the environment. Some fungi exhibit a remarkable ability to accumulate heavy metals; however, the molecular basis of this process remains poorly understood. This study investigates the metal tolerance and uptake capabilities of Agaricus crocodilinus mycelium, focusing on cadmium (Cd) and zinc (Zn). The mycelium was isolated from a naturally growing sporocarp that showed a Cd concentration of 149 mg kg⁻¹ dry weight, roughly 100-fold higher than typical mushroom levels. Mycelial metal accumulation assays demonstrated a linear relationship for Cd uptake (R² = 0.9977) but a logarithmic relationship for Zn uptake (R² = 0.9965), suggesting unregulated Cd uptake and regulated Zn uptake. Comparison of the A. crocodilinus Zinc-regulated transporter/Iron-regulated transporter-like Protein (ZIP) gene AcZIP1, showed homology with known high-affinity Zn transporters in Agaricomycetes. Functional expression of AcZIP1 in Saccharomyces cerevisiae supported its role in Zn and Cd transport, with localization studies indicating its presence at the plasma membrane. Zn exposure reduced AcZIP1 expression in mycelium ~ 3-fold, while Cd had no significant effect. This study improves our understanding of the possible means of metal uptake in A. crocodilinus and other Agaricomycetes.

In this study, papain (also known as papaya proteinase I; EC 3.4.22.2), a cysteine protease derived from Carica papaya, a tropical fruit cultivated worldwide in tropical and subtropical regions, is used. Biofilm-forming Pseudomonas aeruginosa poses a major therapeutic challenge due to its heightened antibiotic tolerance and ability to persist in chronic infections. This study reports that the enzyme papain inhibits approximately 80% of Pseudomonas aeruginosa biofilm production at a sub-MIC dose of 80 µg/mL, along with reduced levels of pathogenic molecules, including 87% of total acyl-homoserine lactones, 83% of LasA, 85% of LasB, 89% of pyocyanin, 87% of rhamnolipids, and 86% of exoprotease activity. FE-SEM results have confirmed the absence of new biofilm and the disruption of preformed biofilm due to papain treatment of the bacterial cells. AFM results also indicate the lowering of height in papain treated bacterial biofilm. By targeting both preformed and newly formed biofilms, papain offers a promising, sustainable therapeutic strategy derived from a plant source to manage biofilm-associated infections, addressing a critical gap in current antimicrobial approaches. Therefore, papain, a natural antimicrobial protein, has the potential to eradicate biofilms at infected sites.

The increasing resistance of Helicoverpa armigera to currently deployed Bacillus thuringiensis (Bt) genes in transgenic crops necessitates the development of new insecticidal genes that can effectively control this pest. This study evaluates the in-planta efficacy of cry1Ac34, a truncated, plant codon-optimized gene derived from an Indian Bt isolate (SK-783). The cry1Ac34 gene was successfully introduced into Nicotiana tabacum through Agrobacterium-mediated transformation. Following the transformation, PCR-positive T₀ transgenic plants expressing the Cry1Ac34 protein were identified. Subsequent analyses of T₁ progeny lines, using Southern blotting and qRT-PCR, confirmed the stable integration and expression of the gene. Insect bioassays conducted with detached leaves from transgenic lines demonstrated impressive mortality rates of up to 95% in line C12 of T₁ against first larval instars of H. armigera. Protein expression levels in T₁ transgenic plants ranged from 0.86 µg/g to 1.36 µg/g fresh leaf weight. Additionally, the study observed significant sub-lethal effects, including reduced weight gain and larval growth, delays in pupation, and pre-pupal death. Histopathological analysis revealed disintegration of brush border membranes in the midguts of fourth instar larvae that had been fed transgenic leaves. The successful expression and efficacy of the codon-optimized cry1Ac34 gene highlight its potential as a viable solution for controlling H. armigera. This research suggests cry1Ac34 as a promising candidate for deployment in the development of new insect-resistant transgenic crops, which may help combat the escalating resistance challenges currently faced in agricultural pest management.

Mycotoxin contamination remains a significant challenge to poultry health and productivity globally. Conventional detoxification methods, such as chemical adsorption and thermal degradation, are often limited by high costs, nutrient losses, and incomplete toxin removal. In contrast, probiotics offer a promising biological alternative for mycotoxin detoxification. This review critically evaluates the role of probiotics, such as Lactobacillus, Bacillus, and Saccharomyces, in mitigating mycotoxin toxicity through mechanisms of adsorption to cell wall polysaccharides and enzymatic degradation. Probiotic strains Lactobacillus casei and Saccharomyces cerevisiae achieve adsorption efficiencies exceeding 90% for aflatoxins B (AFB₁), while Bacillus strains have demonstrated up to 65% reduction in deoxynivalenol levels in vitro. The detoxification efficacy of probiotics is highly strain- and dose-dependent, with reductions in AFB₁ residues ranging from 30 to 60% in poultry tissue during in vivo trials. While adsorption is well established, the in vivo enzymatic degradation mechanisms remain underexplored, with some strains showing up to a 40% reduction in toxin residues through enzymatic biotransformation. Additionally, emerging strategies using microbial consortia and genetically modified probiotics show promising results, with consortia reducing toxin loads by 40–65% in field trials. However, large-scale validation and consistent performance in commercial poultry production remain limited. This review identifies critical research gaps, including strain selection, biofilm regulation, and the need for standardized field-level efficacy trials. Probiotic-based detoxification is positioned as a biologically sustainable complement to, rather than a complete replacement for, conventional chemical methods, offering potential for safer feed and improved poultry health within a broader food safety framework.

Plants, being sessile organisms, are perpetually subjected to a spectrum of escalating abiotic stresses, which have detrimental repercussions on agriculture worldwide. In the forthcoming era of climate change and ecosystem degradation, fostering the use of beneficial microbiota in agroecosystems represents a major challenge towards sustainability. Some plant-associated bacteria, called Plant Growth Promoting Rhizobacteria (PGPR), may confer growth-promoting advantages to the host plant through enhancing nutrient uptake, altering hormone homeostasis, and/or improving tolerance to abiotic stress factors (drought, heavy metal, and salinity stress) in plants. These include promoting plant growth through the activation of antioxidant enzymes to detoxify reactive oxygen species, accumulation of compatible solutes to maintain osmotic homeostasis, suppression of lipid peroxidation to conserve membrane integrity, and emission of volatile organic compounds to induce systemic resistance. Additionally, PGPR synthesize phytohormones and exopolysaccharides that reinforce their persistence in soil, improve plant-water relations, and optimize nutrient uptake efficiency. In this regard, exploring the key ecological and evolutionary interactions between plants and their microbiomes is a prerequisite to developing innovative approaches and novel natural products that will complement conventional farming techniques. Collectively, these interactions fortify plant defense mechanisms, enhance physiological homeostasis, and promote adaptive plasticity in adverse environments. Herein, we describe the role of plant-microbe interactions in mitigating abiotic stress and fostering sustainable crop production. Leveraging multifactorial PGPR in agroecosystems strengthens the adaptive resilience of plants, reduces dependency on synthetic fertilizers, maintains soil microbiome integrity, cellular homeostasis, nutrient cycling, improves water retention, and ensures sustainable productivity in stress-prone and resource-limited regions.

Chikungunya virus (CHIKV) is one of the well-known arboviruses, transmitted via Aedes mosquitoes and infects humans through vector bites. The virus is endemic in certain countries; however, there is evidence suggesting that CHIKV may become widespread in non-endemic countries and may cause a significant burden on global health status in the future. In this context, exploring the characteristics of CHIKV enhances our understanding of it. This literature review examines alterations in host cell signaling induced by CHIKV, including those related to the phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK), janus kinase/signal transducers and activators of transcription (JAK/STAT), Wnt, transforming growth factor-β (TGF-β), and P53 pathways. We also review the effect of CHIKV on mitochondria and related processes, such as apoptosis, ferroptosis, and autophagy. The altered signals are involved in viral infection and manifestation. In that case, they may be suitable therapeutic targets for treating and preventing CHIKV. Multiple studies reveal that CHIKV infection alters the PI3K/AKT and MAPK pathways, indicating their essential involvement in host signaling. Hence, these pathways (and also other mentioned ones) may be proper candidates for treatment or prevention of the virus. Further studies are required to explore more details about CHIKV-induced intracellular signaling alternation and its subsequent effects. These findings provide a deeper understanding of the fundamental molecular mechanisms underlying CHIKV infection, paving the way for the development of antiviral strategies.

Erigeron breviscapus (Vant.) Hand-Mazz possesses anti-inflammatory and antioxidant properties, yet its therapeutic application is limited by the low yield of active components. Fermentation technology offers a promising strategy for enhancing the enrichment of these bioactive compounds. In this study, anaerobic self-induced fermentation was identified as the most effective approach among 12 evaluated fermentation strategies. Under optimized conditions, this method markedly increased the production of scutellarein—achieving a 20.35-fold enhancement—while reducing microbial α-diversity and inducing notable community restructuring, characterized by a shift from Proteobacteria to Firmicutes in bacteria and from Ascomycota to Basidiomycota in fungi. Metabolomic analysis revealed 223 differentially expressed metabolites, primarily enriched in flavonoid biosynthesis and phenylalanine metabolism pathways. Key bacterial genera, including Clostridium and Bacillus, showed strong correlations with increased flavonoid accumulation. Furthermore, the anaerobically self-fermented extract exhibited significantly enhanced antibacterial and antioxidant activities. These findings demonstrate that anaerobic self-induced fermentation represents an effective and targeted bioprocessing strategy for amplifying the bioactivity and therapeutic potential of E. breviscapus.

Zinc metalloproteases are pivotal catalytic enzymes that facilitate zinc-dependent selective cleavage of peptide bonds within proteins. Zinc metalloproteases are widely distributed across bacterial species, particularly pathogens, where they act as multifaceted virulence factors. Bacillus anthracis produces the zinc metalloproteases Lethal Factor (LF), InhA1, and Npr599, which exhibit versatile host-targeting activities, including disruption of immune responses, facilitation of bacterial dissemination and tissue invasion, and modulation of the bacterial secretome. GelE, from Enterococcus faecalis, regulates biofilm formation, bacterial adherence and dissemination, and expedites host invasion and inflammation. Burkholderia cenocepacia’s ZmpB contributes to antimicrobial tolerance and nutrient acquisition, whereas in Mycobacterium tuberculosis, Zmp1 mediates immunomodulatory functions, whilst Rip1 regulates intramembrane proteolysis and activates stress response pathways. This review consolidates current knowledge on bacterial zinc metalloproteases and their roles in disease, and advocates for comprehensive research that holistically elucidates zinc metalloproteases, as such integrated understanding is essential for their effective application as therapeutic targets.

Moisture stress is one of the major factors affecting crop productivity and food security. Although several management practices are available, eco-friendly microbial approaches provide sustainable solutions through mechanisms such as nutrient solubilization, phytohormone production, biofilm formation, osmolyte accumulation and metabolite production. Among plant growth-promoting microbes, yeasts remain less explored for their role in drought tolerance. The present study aimed to evaluate the potential of yeast in mitigating moisture stress and promoting rice growth. Fifty isolates were obtained from soil samples, of which 18 isolates survived up to 30% PEG 6000. Further, the isolates were evaluated for plant growth-promoting (PGP) traits, including the indole acetic acid, siderophore, and exopolysaccharides production, phosphorus and zinc solubilization, and biofilm formation under increasing PEG concentrations (0, 10, 20 and 30%). Among the 18, five well-performing isolates S2R2, CAL, SF, SA1, and V1BG were selected for further experiments. All these five isolates demonstrated ACC deaminase activity (maximum of 111.50 nmole of α-ketobutyrate mg^− 1 protein h^− 1) and osmolytes accumulation such as proline, trehalose and glycine betaine. Moreover, these isolates on seed biotization improved seed germination and seedling growth under moisture stress. Metabolite profiling revealed that production of phenols, alkaloids, and amino acids was predominant under PEG-induced stress and associated with plant growth promotion. Overall findings highlight the potential of yeast as bioinoculants for enhancing drought resilience and growth promotion in rice.