Search Results (622)

Research has evaluated the efficacy of various methods for eliminating endophytes from grass seeds, as well as changes in endophyte viability during seed storage under different conditions, indicating significant variation in different procedures and cultivars. Chemical seed treatment (tebuconazole and thiram) completely eliminated viable fungal mycelia, leaving no trace in any tested cultivar. Non-chemical methods, such as drying and microwave treatment, only partially reduced mycelial viability by 30.3% and 33.1%, respectively, with no statistically significant difference between them. A significant positive correlation was observed between the initial mycelial viability and its reduction. Lolium perenne cv. Vigor showed no impact from non-chemical methods, while Festuca rubra cv. Anielka exhibited the greatest reduction (79% after microwave treatment). Seed storage also impacted endophyte survival. Storage at +7 °C, +23 °C, and −20 °C reduced viability by 27.4%, 31.7%, and 37.3%, respectively. Positive correlations existed between initial viability and post-storage reductions. Similarly to elimination methods, cv. Vigor showed resistance to storage conditions. However, −20 °C storage proved least favorable for endophyte survival, particularly for Festuca pratensis cv. Artema, cv. Anielka, and Festuca ovina cv. Jolka. To maintain the viability of beneficial endophytes during seed storage, we must carefully control storage conditions, especially ambient temperature. Full article

Antrodia cinnamomea, a renowned rare medicinal fungus in China, is rich in active components, exhibiting pharmacological effects, such as liver protection, hypoglycemic activity, and anti-tumor properties. Aiming to address the lack of horizontal comparative studies on volatile components of A. cinnamomea under different culture methods and the limitations of traditional detection methods, this study investigated the mycelia of A. cinnamomea cultured by solid-state culture (SAC), liquid culture (LAC), and dish culture (DAC). The flavor profiles were comprehensively evaluated using a combination of electronic tongue (E-tongue), electronic nose (E-nose), gas chromatography–ion mobility spectrometry (GC-IMS), and multivariate statistical methods. Results from E-tongue and E-nose showed distinct flavor profiles among the three culture methods. A total of 75 volatile compounds were detected by GC-IMS, among which esters, alcohols, and ketones were the main components, accounting for 62.7%. Partial least squares discriminant analysis (PLS-DA) identified 41 characteristic volatile compounds, and cluster heatmaps and orthogonal partial least squares discriminant analysis (OPLS-DA) further validated the metabolic preferences among culture methods. These findings provide a scientific basis for improving A. cinnamomea product quality through targeted flavor enhancement, support the development of standardized functional foods, and establish a flavor fingerprint for authenticity assessment, advancing the high-value utilization of this medicinal fungus. Full article

Arthrobotrys flagrans is a typical nematode-trapping fungus that captures nematodes by producing three-dimensional networks. FlbD is a DNA-binding protein containing a Myb domain, which plays a significant role in fungal development. However, the biological function of FlbD in nematode-trapping fungi remains unknown. In this study, we analyzed the physicochemical properties and conserved domains of AfFlbD and constructed the AfFlbD knockout strains (ΔAfFlbD) using homologous recombination. Our functional analysis revealed that the mutants produced more cottony aerial mycelia at the colony center. Additionally, the cell length of the mutants was reduced, indicating that AfFlbD regulates cell morphology in A. flagrans. Chemical stress tolerance assays of the mutants demonstrated reduced sensitivity to NaCl and sorbitol stresses but increased sensitivity to SDS and H₂O₂ stresses compared to the WT strain. Interestingly, the mutants spontaneously produced traps, and its pathogenicity to nematodes was significantly enhanced, suggesting that AfFlbD negatively regulates the pathogenicity of A. flagrans. Furthermore, the number of chlamydospores produced by the mutants was markedly reduced, though their morphology remained unchanged. Fluorescence localization analysis showed that AfFlbD localizes to the nuclei of chlamydospores, thereby regulating chlamydospore formation. This study provides important theoretical insights into the biological function of the FlbD transcription factor and offers new perspectives for the application of nematode-trapping fungi as a method of controlling plant-parasitic nematodes. Full article

In this paper, cultivable actinobacteria were isolated, cultured, and identified from the heavily algal-bloomed waters of Taihu Lake using 16S rRNA gene sequencing. Among the isolates, a single strain exhibiting vigorous cyanocidal activity against Microcystis aeruginosa FACHB-905 was selected for further investigation. The cyanocidal efficacy and underlying mechanisms of this strain, designated TH05, were assessed through using chlorophyll content, cyanobacterial inhibition rate, and cyanobacterial cell morphology measurements. In addition, oxidative stress responses, expression of key functional genes in FACHB-905, and variations in microcystin concentrations were comprehensively evaluated. Cyanobacterial blooms caused by Microcystis aeruginosa pose serious ecological and public health threats due to the release of microcystins (MCs). In this study, we evaluated the cyanocidal activity and mechanism of a novel actinomycete strain, Streptomyces sp. TH05. Optimization experiments revealed that a light–dark cycle of 12 h/12 h, temperature of 25 °C, and pH 7 significantly enhanced cyanocidal efficacy. Under these conditions, TH05 achieved an 84.31% inhibition rate after seven days of co-cultivation with M. aeruginosa. Scanning electron microscopy revealed two distinct cyanocidal modes: direct physical attachment of TH05 mycelia to cyanobacterial cells, causing cell wall disruption, and indirect membrane damage via extracellular bioactive compounds. Biochemical analyses showed increased levels of malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) during the first five days, peaking at 2.47-, 2.12-, and 1.91-fold higher than control levels, respectively, indicating elevated oxidative stress. Gene expression analysis using elf-p as a reference showed that TH05 modulated key genes associated with photosynthesis (PsaB, PstD1, PstD2, RbcL), DNA repair and stress response (RecA, FtsH), and microcystin biosynthesis (McyA, McyD). All genes were upregulated except for RbcL, which was downregulated. In parallel, microcystin content peaked at 32.25 ng/L on day 1 and decreased to 16.16 ng/L by day 9, which was significantly lower than that of the control group on day 9 (29.03 ng/L). These findings suggest that strain TH05 exhibits potent and multifaceted cyanocidal activity, underscoring its potential for application in the biological control of cyanobacterial blooms. Full article

In this study, the molecular mechanism underlying melanin synthesis within the fermentation broth of Auricularia heimuer (A. heimuer) was explored. The absorbance at 500 nm, melanin yield, and tyrosinase activity in the fermentation broth were assessed across different fermentation durations. Mycelia samples were gathered on the 4th (R1), 8th (R2), and 10th (R3) days of liquid fermentation for transcriptome sequencing. As fermentation progressed, the absorbance, melanin yield, and tyrosinase activity in the broth rose. A total of 5915 differentially expressed genes (DEGs) were detected, with 1136 DEGs between R2 and R1, 3717 between R3 and R1, and 2950 between R3 and R2. Gene Ontology (GO) analysis showed that DEGs were significantly enriched in oxidoreductase activity and ribosome structural constituent terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed significant enrichment of DEGs in ribosome and amino acid metabolism pathways. Key DEGs, including transcription factors, glycosidases, P450 enzymes, laccases, and glutamate dehydrogenase, were identified during melanin production in the fermentation broth. These DEGs may play crucial roles in melanin synthesis. This study offers a foundation for further exploring the melanin synthesis mechanism in A. heimuer fermentation broth. Full article

The mycelia of Hericium erinaceus contain neuroprotective cyathane diterpenoids (e.g., erinacine A). There is evidence that cultivation of submerged mycelia with surfactants increases glucose uptake and biomass, but the impact on erinacine production is unknown. Here, we tested the impact of glucose and polysorbate 80 on the mycelial erinacine profiles of five Hericium strains cultivated under submergence, including those of Hericium erinaceus, Hericium americanum, and Hericium coralloides. Metabolite profiling confirmed that mycelial extracts contained 13% to 91% of the erinacines A, C and P in additive-free cultures of all strains, with the remainder secreted to the culture medium. Overall, erinacine P production was several orders of magnitude greater than that of the other erinacines, except for H. erinaceus (DAOMC 251029), where erinacine C was most evident. H. coralloides (DAOMC 251017) produced the greatest concentrations of erinacines A and P. For the most part mycelial erinacine concentrations were reduced in cultures co-supplemented with glucose and polysorbate 80. This treatment caused an 83–100% reduction in the concentrations of erinacines A, C, and P in the mycelial extracts of most strains. By contrast, there was evidence that glucose and polysorbate 80 had no effect on erinacine A production within mycelia of H. americanum, and erinacine P concentrations in H. erinaceus (DAOMC 251029) and H. americanum (DAOMC 251011). In most strains, the secretion of erinacines to the culture medium declined with glucose and polysorbate 80. Conversely, these additives increased the concentrations of erinacines C and P in the culture medium filtrate of H. americanum (DAOMC 21467) and yielded more secreted erinacine P in H. erinaceus (DAOMC 251029). The information provides feasible strategies to produce mycelia with unique erinacine profiles including those rich in erinacine P. Full article

Citral, an organic compound found in lemongrass (Cymbopogon citratus) oil and Litsea cubeba essential oil, has been reported to exhibit notable antifungal activity against Magnaporthe oryzae (M. oryzae), the pathogen of rice blast, which causes significant economic losses in rice production. However, the role of citral in inducing oxidative stress related to antifungal ability and its underlying regulatory networks in M. oryzae remain unclear. In this study, we investigated the oxidative effects of citral on M. oryzae and conducted transcriptomic and widely targeted metabolomic (WTM) analyses on the mycelia. The results showed that citral induced superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) activities but reduced glutathione S-transferase (GST) activity with 25% maximal effective concentration (EC₂₅) and 75% maximal effective concentration (EC₇₅). Importantly, citral at EC₇₅ reduced the activities of mitochondrial respiratory chain complex I, complex III and ATP content, while increasing the activity of mitochondrial respiratory chain complex II. In addition, citral triggered a burst of reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP) through the observation of fluorescence. Furthermore, RNA-seq analysis and metabolomics analysis identified a total of 466 differentially expression genes (DEGs) and 32 differential metabolites (DAMs) after the mycelia were treated with citral. The following multi-omics analysis revealed that the metabolic pathways centered on AsA, GSH and melatonin were obviously suppressed by citral, indicating a disrupted redox equilibrium in the cell. These findings provide further evidences supporting the antifungal activity of citral and offer new insights into the response of M. oryzae under oxidative stress induced by citral. Full article

In this study, we investigated the potential of a three-mushroom complex extract (GMK) to inhibit neuronal cell death induced by the activation of AMPA and NMDA receptors following glutamate treatment in NGF-differentiated PC12 neuronal cells. GMK significantly mitigated glutamate-induced excitotoxic neuronal apoptosis by reducing the elevated expression of BAX, a critical regulator of apoptosis, and restoring BCL2 levels. These neuroprotective effects were associated with redox regulation, as evidenced by the upregulation of SOD, CAT, and GSH levels, and the downregulation of MDA levels. Mechanistic studies further revealed that GMK effectively scavenged ROS by downregulating NOX1, NOX2, and NOX4, while upregulating NRF1, P62, NRF2, HO1, and NQO1. Additionally, in the same model, GMK treatment increased acetylcholine, choline acetyltransferase, and GABA levels while reducing acetylcholinesterase activity. These effects were also attributed to the regulation of redox balance. Furthermore, we investigated the antioxidant and anti-inflammatory mechanisms of GMK in LPS-stimulated BV2 microglia. GMK inhibited the activation of IκB and MAPK pathways, positively regulated the BCL2/BAX ratio, suppressed TXNIP activity, and upregulated NQO1 and NOX1. In conclusion, GMK improved neuronal excitotoxicity and microglial inflammation through the positive modulation of the redox regulatory system, demonstrating its potential as a natural resource for pharmaceutical applications and functional health foods. Full article

Citrus fruits are major economic and nutritional crops that are sometimes subjected to serious attacks by many fungal phytopathogens after harvesting. In this study, we focus on the structures of potential antifungal nanocomposites from artichoke leaf extract (Art), Art-mediated nanosilver (AgNPs), and their nanoconjugates with chitosan nanoparticles (Cht) to eradicate the blue mold fungus (Penicillium italicum) and preserve oranges during storage via nanocomposite-based edible coatings (ECs). The biosynthesis and conjugation of nanomaterials were verified using UV and infrared (FTIR) spectroscopy, electron microscopy (TEM and SEM) analysis, and DLS assessments. Art could effectually biosynthesize/cap AgNPs with a mean size of 10.35 nm, whereas the average size of Cht was 148.67 nm, and the particles of their nanocomposites had average diameters of 203.22 nm. All nanomaterials/composites exhibited potent antifungal action toward P. italicum isolates; the Cht/Art/AgNP nanocomposite was the most effectual, with an inhibition zone of 31.1 mm and a fungicidal concentration of 17.5 mg/mL, significantly exceeding the activity of other compounds and the fungicide Enilconazole (24.8 mm and 25.0 mg/mL, respectively). The microscopic imaging of P. italicum mycelia treated with Cht/Art/AgNP nanocomposites emphasized their action for the complete destruction of mycelia within 24 h. The orange (Citrus sinensis) fruit coatings, with nanomaterial-based ECs, were highly effectual for preventing blue mold development and preserved fruits for >14 days without any infestation signs; when the control infected fruits were fully covered with blue mold, the infestation remarks covered 12.4%, 5.2%, and 0% of the orange coated with Cht Art/AgNPs and Cht/Art/AgNPs. The constructed Cht/Art/AgNP nanocomposites have potential as effectual biomaterials for protecting citrus fruits from fungal deterioration and preserving their quality. Full article

This study investigated Morchella importuna strain degeneration during repeated subculturing and employed metabolomics, transcriptomics, and other techniques to explore its molecular mechanisms. Significant metabolic and transcriptional differences were observed between normal mycelia (NM) and degenerated mycelia (DG). Metabolomic analysis revealed 699 differentially expressed metabolites (DEMs) that were predominantly enriched in secondary metabolite biosynthesis pathways, particularly flavonoids and indole alkaloids. Total flavonoid content was markedly higher in NM than in DG, with most flavonoid compounds showing reduced levels in degenerated strains. Transcriptomic profiling revealed 2691 differentially expressed genes (DEGs), primarily associated with metabolic pathways and genetic information processing. Integrated analysis showed that metabolic dynamics were regulated by DEGs, with pyruvate metabolism being significantly enriched. The FunBGCeX tool identified biosynthetic gene clusters (BGCs) in the M. importuna genome, highlighting the critical role of the non-reducing polyketide synthase (NR-PKS) gene in flavonoid biosynthesis. This gene exhibited significantly downregulated expression in DG strains. These findings indicate that M. importuna degeneration resulted from systemic dysregulation of gene expression networks and metabolic pathway reorganization. The results presented herein also provide theoretical insights into degeneration mechanisms and potential prevention strategies for this edible fungus. Full article

With the increasing scarcity of traditional hardwood sawdust resources, developing sustainable substrates for edible fungi cultivation has become an urgent industrial priority. This study systematically evaluated the effects of bamboo sawdust substitutions (20%, 30%, 40%, and 50%) on mycelial growth, fruiting body development, and nutritional quality of Auricularia heimuer, while elucidating the underlying molecular mechanisms through transcriptome sequencing. The results demonstrated that bamboo substitution of ≤30% maintained normal mycelial growth and fruiting body differentiation, with 20% and 30% substitutions increasing yields by 5.30% and 3.70%, respectively, compared to the control. However, 50% substitution significantly reduced yield by 9.49%. Nutritional analysis revealed that 20–40% bamboo substitution significantly enhanced the contents of crude protein, polysaccharides, and essential minerals (calcium, iron, and selenium) in fruiting bodies. Transcriptome analysis identified upregulation of glycosyl hydrolase family genes and downregulation of redox-related genes with increasing bamboo proportions. Biochemical assays confirmed these findings, showing decreased oxidative substances and increased reductive compounds in mycelia grown with high bamboo content, which indicate disrupted cellular redox homeostasis. This study provides both a practical solution to alleviate the “edible mushrooms derived from lignicolous fungi–forest conflict” and fundamental insights into fungal adaptation mechanisms to non-wood substrates, thus establishing a theoretical foundation for the valorization of agricultural and forestry wastes. Full article

Pholiota adiposa is a macrofungi that is rich in nutrients and has a delicious taste. Eating more can improve human immunity and inhibit cancer. However, the P. adiposa yield is low and cannot meet market demand. Therefore, strain improvement was carried out by exploring the mechanism of stress adaptation in P. adiposa. In addition, fermentation of the four common grains by P. adiposa mycelia increased their nutrient content and improved their antioxidant capacity. The results revealed that the growth of the mycelium was greatest when sucrose was used as the carbon source at 25 °C. At 35 °C, the MDA content and cellulase enzyme activity of the mycelia decreased by 27.6% and 40.8%, respectively, from 2 to 4 days, and the SOD, CAT, and GR enzyme activities increased by 31.6%, 49.2%, and 1.2%, respectively. The fermentation results revealed that the soluble protein content, reducing sugar content, and DPPH free radical scavenging ability of the fermented grains were significantly greater than those of the unfermented grains. This study can be used to cultivate macrofungi with environmental adaptability and provides a basis for the utilization of biological waste and increased food nutrition. Full article

Heavy metal toxicity leads to impaired crop growth and reduced crop yields and product quality by disrupting plant nutrient uptake, inhibiting development, inducing oxidative stress, and causing cellular toxicity. Arbuscular mycorrhizal fungi (AMF) can play a crucial role in crops’ adaptation to manganese (Mn) toxicity by regulating nutrient uptake and altering subcellular compartmentalization. The present study examines the influence of intact extraradical mycelia (ERMs) from native AMF on wheat (Triticum aestivum) grown in Mn-toxic soil, with a focus on the tissue-specific and subcellular Ca, Mg, P, and Mn distribution. Wheat cultivated in soil pre-colonized using an intact ERM associated with Lolium rigidum or Ornithopus compressus exhibited enhanced growth and improved P contents. During the first week of growth, the Mn concentrations increased in the wheat’s roots and shoots, but Mn was subsequently reduced and sequestered within the cell wall. In contrast, in the absence of an intact ERM, the Mn accumulation in wheat followed an apparent continuous time-course pattern. AMF-mediated cell wall sequestration seems to contribute to Mn detoxification by limiting excessive cytoplasmic accumulation. Furthermore, AMF-driven changes in the element distribution suggest a dynamic response, wherein an early-stage nutrient uptake transitions into a long-term protective mechanism. These findings highlight the potential of AMF in mitigating Mn stress in crops, providing insights for sustainable agriculture and soil remediation strategies. Full article

Zinc and lysine have been identified as beneficial components of Flammulina filiformis. This work investigated the effects of different concentrations of Zn²⁺ on mycelia growth, zinc content, amino acid composition of F. filiformis. To explore the mechanism of action of zinc on lysine synthesis in F. filiformis mycelia, this work studied at the molecular level. The cultivated strain FV8 and the wild strain FV18 were utilized as the research subjects. Various concentrations of Zn²⁺ (0, 10, 20, 30 mg/L) were added in the PDA medium for the experiments. The results indicated that the maximum lysine content was reached in the 20 mg/L treatment. A positive correlation was identified between Zn²⁺ and the lysine content in F. filiformis mycelia, suggesting a regulatory role for Zn²⁺ in the expression of lysine synthesis pathway genes. Zn²⁺ has been observed to promote the upregulated expression of HDH and HCD, while concomitantly exerting a negative effect on the expression of AAT in key enzyme genes of the lysine synthesis pathway. The F. filiformis mycelia exhibited a notable enrichment capacity for zinc, with the highest zinc content observed in the 30 mg/L treatment. The zinc-enriched growth performance of wild strain FV18 was found to be superior to that of cultivated strain FV8, which is considered a suitable breeding material. This study provides a foundation for further exploration of the lysine synthesis pathway in F. filiformis mycelia, and selection of functional varieties of F. filiformis. Full article

Spent mushroom substrate (SMS), a waste product from mushroom cultivation, in addition to being rich in essential nutrients for crop growth, contains actively growing mushroom mycelia and metabolites that suppress some plant pathogens and pests. SMS thus has potential for fostering the suppressiveness of soil-borne pathogens of farms. This study determined the potential of using the spent Pleurotus ostreatus substrate (SPoS) to suppress the plant-parasitic nematode Radopholus similis in bananas. R. similis is the most economically important nematode in bananas worldwide. The effect of SPoS on R. similis was assessed through two in vivo (potted plants) experiments between May 2023 and June 2024. Five-month-old East African highland banana (genome AAA) plantlets that are highly susceptible to R. similis were used. In the first experiment, the plantlets were established in 3 L pots containing (i) pre-sterilized soil, (ii) pre-sterilized soil inoculated with nematodes, (iii) pre-sterilized soil mixed with 30% (v/v) SPoS, (iv) pre-sterilized soil mixed with 30% (v/v) SPoS followed by nematode inoculation, (v) SPoS without soil, and (vi) SPoS without soil inoculated with nematodes. The SPoS was already decomposed; thus, it may or may not have contained active mycelia. The nematodes were introduced two weeks after the SPoS application. In the second experiment, SPoS was introduced two weeks after nematode inoculation. The SPoS treatments without soil were not evaluated in the second experiment. Both experiments were monitored over a three-month period. Each screenhouse treatment contained four plants and was replicated thrice. In the first experiment, data were collected on changes in soil nutrient content, below- and aboveground biomass, root deaths, root necrosis due to nematode damage, and R. similis population in root tissues and soil. In the second experiment, data were collected on root deaths and the number of nematodes in root tissues and the soil. The SPoS improved crop biomass yield, reduced root damage, and colonization by R. similis. The potential of SPoS to improve the management of R. similis and banana production under field conditions needs to be determined. Full article