Search Results (401)

The majority of studies of fungal utilization of chitosan are associated with the production of a specific enzyme, chitosanase, which catalyzes the hydrolytic cleavage of the macrochain. In our opinion, the development of approaches to obtaining materials with new functional properties based on non-destructive chitosan transformation by living organisms and their enzyme systems is promising. This study was conducted using a wide range of classical and modern methods of microbiology, biochemistry, and physical chemistry. The ability of the ascomycete Fusarium oxysporum Schltdl. to modify films of chitosan with average-viscosity molecular weights of 200, 450, and 530 kDa was discovered. F. oxysporum was shown to use chitosan as the sole source of carbon/energy and actively overgrew films without deformations and signs of integrity loss. Scanning electron microscopy (SEM) recorded an increase in the porosity of film substrates. An analysis of the FTIR spectra revealed the occurrence of oxidation processes and crosslinking of macrochains without breaking β-(1,4)-glycosidic bonds. After F. oxysporum growth, the resistance of the films to mechanical dispersion and the degree of ordering of the polymer structure increased, while their solubility in the acetate buffer with pH 4.4 and sorption capacity for Fe²⁺ and Cu²⁺ decreased. Elemental analysis revealed a decrease in the nitrogen content in chitosan, which may indicate its inclusion into the fungal metabolism. The film transformation was accompanied by the production of extracellular hydrolase (different from chitosanase) and peroxidase, as well as biosurfactants. The results obtained indicate a specific mechanism of aminopolysaccharide transformation by F. oxysporum. Although the biochemical mechanisms of action remain to be analyzed in detail, the results obtained create new ways of using fungi and show the potential for the use of Fusarium and/or its extracellular enzymes for the formation of chitosan-containing materials with the required range of functional properties and qualities for biotechnological applications. Full article

Fungal cell walls, composed of polysaccharides and proteins, play critical roles in adaptation, cell division, and protection against environmental stress. Their polyglucan components are continuously remodeled by various types of glycosyl hydrolases (GHs) and transferases (GTs). In Saccharomyces cerevisiae and other ascomycetes, enzymes of the Dfg5 subfamily, which belong as GTs to the GH76 family, cleave an α1,4 linkage between glucosamine and mannose to facilitate covalent linkage of GPI-anchored proteins to the cell wall’s polyglucans. In contrast, the functions of other fungal GH76 subfamilies are not understood. We characterized CtGH76 from the sordariomycete Chaetomium thermophilum, a member of the Fungi/Bacteria-mixed GH76 subfamily, revealing conserved structural features and functional divergence within the GH76 family. Notably, our structural characterization by X-ray crystallography combined with glycan fragment screening indicated that CtGH76 can recognize GPI-anchors like members of the Dfg5 subfamily but shows a broader promiscuity toward other glycans with central α1,6-mannobiose motifs due to the presence of an elongated glycan-binding canyon. These findings provide new insights into GH76 enzyme diversity and fungal cell wall maturation. Full article

Rice blast disease, caused by the ascomycete fungus Magnaporthe oryzae (syn. Pyricularia oryzae), poses a severe threat to global rice production. Southern China, a major rice-growing region characterized by diverse agroecological conditions, faces substantial challenges from blast disease, yet our understanding of the genetic structure of M. oryzae populations in this region remains limited. Here, we analyzed 885 M. oryzae strains from 18 nurseries across four rice ecological regions in Southern China using a panel of genome-wide SNP markers. Phylogenetic and principal component analyses revealed three distinct clonal lineages: lineage I (58.19%), lineage II (21.36%), and lineage III (20.45%). Lineage I exhibited a broader geographic distribution compared to the other two lineages. Host-adapted divergence was observed across rice subspecies, with lineage III predominantly associated with japonica growing-regions, while lineages I and II mainly colonized indica rice-growing regions. Genetic diversity exhibited significant spatial heterogeneity, with the nucleotide diversity (π) ranging from 0.17 in South China to 0.32 in the Middle–Lower Yangtze River region, reflecting differential cropping systems. The predominantly negative Tajima’s D values across populations suggested recent expansion or selective sweeps, likely driven by host resistance pressures. High genetic differentiation between lineage I and other lineages contrasted with low divergence between lineages II and III, indicating distinct evolutionary trajectories. Furthermore, an uneven distribution of mating types among three genetic lineages was observed, suggesting limited sexual recombination within clonal lineages. The information obtained in this study may be beneficial in devising suitable strategies to control rice blast disease in Southern China. Full article

During a survey of ascomycetous fungi associated with plant litter and submerged wood in Jilin Province, China, two hyphomycetous fungi were discovered. Morphological examination and molecular phylogenetic analyses revealed that these isolates represent two species within the genus Torula, which are herein described as Torula changchunensis sp. nov. and a new host record of T. mackenziei. Detailed morphological characteristics are provided, and the phylogenetic relationships of the new species are also discussed. The new species differs from T. chinensis and T. phytolaccae by having smaller conidiogenous cells, smaller conidia, and fewer septa. Preliminary assessments were conducted on T. changchunensis and T. mackenziei to evaluate their antagonistic activity against two pathogenic fungi (Cladobotryum mycophilum and Botrytis cinerea) and two pathogenic bacteria (Staphylococcus aureus and Bacillus subtilis). Torula changchunensis sp. nov. exhibited 67.18% inhibition against C. mycophilum and moderate inhibition against the pathogenic bacteria, whereas Torula mackenziei showed moderate-to-weak inhibitory activity against both pathogenic fungi and bacteria. Full article

Magnaporthe oryzae (M. oryzae) is a phytopathogenic fungus that inflicts damage on vital crops, particularly rice. Its asexual reproduction leads to the generation of numerous conidia, which is a critical factor contributing to the prevalence of rice blast disease. However, the molecules regulating the asexual reproduction of M. oryzae are unknown. In our study, to identify the molecules capable of regulating the asexual reproduction of M. oryzae, compositions of the complete medium (CM) were screened. Results showed that acid-hydrolyzed casein (AHC) could remarkably promote conidial production. One M. oryzae conidiation inducer was isolated from AHC using high-performance liquid chromatography (HPLC) under the guidance of bioassay. Its structure was further elucidated as a decapeptide compound (pyroGlu-EQNQEQPIR) by LC-MS/MS, chemical synthesis, and conidium-inducing assays, named M. oryzae conidiation inducer decapeptide (MCIDP). MCIDP could significantly promote the conidiation of M. oryzae and two other filamentous ascomycetes (Botrytis cinerea and Fusarium graminearum). The Mps1 MAPK cascade signaling pathway is crucial for conidiation, and the effect of MCIDP on this pathway was investigated to elucidate the mechanism underlying conidiation enhancement. qRT-PCR analysis demonstrated that MCIDP could remarkably upregulate the gene expression within the Mps1 MAPK cascade signaling pathway, especially the WSC2, WSC3, PKC1, MKK1, MPS1, and MIG1. Furthermore, the ΔMowsc1, ΔMowsc2, ΔMowsc3, and ΔMomid2 mutant strains were constructed. Bioassay results showed that MCIDP failed to promote conidial formation and hyphal growth in these mutant strains. These findings indicate that MCIDP promotes conidiation of M. oryzae by modulating the Mps1 MAPK signaling pathway. Full article

Fungi are a diverse and essential group that play crucial ecological roles. However, they remain understudied in tropical countries like Ecuador in terms of their forest or protected areas, particularly across diverse ecosystem zones such as seasonal forests and salt flats. This study aimed to inventory fungal diversity in two specific zones: the dry forest (DF) and the salt flat (SF) within the Reserva Ecologica Arenillas (REAR), located in El Oro, Ecuador. The results recorded 162 specimens representing 47 species belonging to 34 genera, identified morphologically. Although statistically significant, the difference in species richness and abundance between the dry forest and the salt flat was minimal, with the dry forest showing slightly higher values. Nonetheless, certain species were prevalent in both ecosystems, such as Cerrena hydnoides, Pycnoporus sanguineus, Hexagonia tenuis, and Chondrostereum sp., alongside four species with resupinate habit, all of them growing on decayed wood. The Shannon and Simpson indices were calculated to assess alpha diversity, revealing higher diversity in the DF. To evaluate differences in community composition between habitats, non-metric multidimensional scaling (NMDS) and permutational analysis of variance (PERMANOVA) were applied, indicating greater species turnover and dominance of specific taxa in the DF compared to the SF. These findings highlight the importance of the fungal diversity found in the REAR while also pointing to the need for more exhaustive monitoring and comparative studies with other wild or protected areas to fully understand and conserve this biodiversity. Full article

Four different yeast strains were isolated from industrial gluten-free bread (GFB) purchased from a local supermarket. These strains, including Hyphopichia burtonii, Wickerhamomyces anomalus, Saccharomycopsis fibuligera, and Cyberlindnera fabianii, are responsible for spoilage, which consists of white powdery and filamentous colonies due to the fragmentation of hyphae into short-length fragments (dust-type spots) that is typical of the spoilage produced by chalk yeasts. The isolated strains were identified using genomic analysis. Among them, C. fabianii was also isolated, which is a rare ascomycetous opportunistic yeast species with low virulence attributes, uncommonly implicated in bread spoilage. The yeast growth was studied in vitro on Malt Extract Agar (MEA) at two temperatures (20 and 25 °C) and at different Aws (from 0.99 to 0.90). It was inferred that the temperature did not influence the growth. On the contrary, different Aws reduced the growth, but all the yeast strains could grow until a minimum Aw of about 0.90. Different preservatives (ethanol, hop extract, and sorbic and propionic acids) were used to prevent the growth. In MEA, the growth was reduced but not inhibited. In addition, the vapor-phase antimicrobial activity of different preservatives such as ethanol and hop extract was studied in MEA. Both preservatives completely inhibited the yeast growth either at 20 or at 25 °C. Both preservatives were found in GFB slices. Contrary to hop extract, 2% (v/w) ethanol completely inhibited all the strains. The spoilage was also confirmed by the presence of various compounds typically present in yeasts, derived from sugar fermentation and amino acid degradation. These compounds included alcohols, ketones, organic acids, and esters, and they were identified at higher concentrations in the spoiled samples than in the unspoiled samples. The concentration of acetic acid was low only in the spoiled samples, as this compound was consumed by yeasts, which are predominately present in the spoiled samples, to produce acetate esters. Full article

The World Health Organization (WHO) prioritized 19 fungal species based on the significant impact of these pathogens on human health, including the emergence of antifungal resistance, which highlights the necessity of finding new antifungal therapies. Among these novel therapeutic approaches, the antimicrobial pore-forming peptide C14R has shown to be promising against Candida albicans and Candida auris. In this study, the antifungal in vitro efficacy of C14R was assessed against six additional species from the WHO priority list, Cryptococcus neoformans, Cryptococcus gattii, Candida glabrata, Candida tropicalis, Candida parapsilosis and Candida krusei, as well as against Candida dubliniensis. This study shows that C14R has good antifungal activity against several clinical isolates of the studied species, with MIC values between 0.8476 and 10.88 µg/mL. Most notably, some of the studied isolates are resistant to commonly used antifungal drugs but are susceptible to the peptide. C14R showed, moreover, its capacity to disrupt Cryptococcus capsules, beyond its already proven capacity to disrupt plasma membranes, and its antifungal activity was not affected depending on the serotype or species assessed. The inclusion of basidiomycete and ascomycete yeasts allowed us to display the broad-spectrum potential of C14R, highlighting it as a promising candidate as an antifungal agent. Full article

In ex situ conservation, gut bacteria and fungi play a crucial role in maintaining the intestinal microecological balance of the gut, and disruptions in this system may negatively impact host health. The South China tiger (Panthera tigris amoyensis) is a critically endangered tiger subspecies currently surviving under human-managed care and captive breeding programs, with only a small number of individuals remaining. Disruption in the gut microbiota, particularly the proliferation of pathogenic bacteria, can be fatal for cubs. This study analyzed the composition and seasonal changes of the gut bacterial and fungal communities of South China tigers in captive and semi-released environments during the winter of 2023 and the summer of 2024, using 16S rRNA and ITS high-throughput sequencing. The results showed that the dominant gut bacteria were Bacillota, Actinomycetota, Fusobacteriota, Pseudomonadota, and Bacteroidota. The abundance of Bacillota decreased in summer and was slightly lower in captive tigers than in semi-released tigers. Fungal communities were dominated by Ascomycota, with a negative correlation observed between Ascomycota and Basidiomycota. The abundance of Ascomycetes was lower in summer but significantly higher in semi-released tigers than in captive ones. Diversity analysis revealed no significant effects of the season or the environment on bacterial α-diversity, and fungal α-diversity was also not significantly affected by seasonal variation. However, microbial diversity increased under semi-free-range conditions, with fungal richness significantly higher than in captive environments (p < 0.01). Principal coordinate analysis (PCoA) based on Bray–Curtis distances revealed significant differences in the community structures of both bacterial (Adonis, R² = 0.2364, p = 0.001) and fungal (Adonis, R² = 0.1542, p = 0.001) communities across different seasons and environments. These findings provide valuable insights into the health management strategies and ecological adaptation of South China tigers. Full article

Restrictions on antimicrobial use in food animal production have been imposed due to concerns over residue accumulation and the development of antibiotic resistance. Thus, there is a need to find potential and safe alternatives to antimicrobials. Some of these natural alternatives include yeasts and their derivatives. Yeasts are single-cell facultative anaerobic ascomycetous eukaryotic fungi that are comprehensively incorporated into poultry nutrition for their potential beneficial effects. They are available as probiotics (whole living yeast cells) or as prebiotics (bioactive derivative components, such as mannan-oligosaccharides, β-glucans, or chitin), along with nucleotides found in distillery yeast sludge or hydrolyzed yeast. The beneficial effects of yeasts and their derivatives stem from their ability to enhance production performance, stimulate immune responses, modulate gut microbiota, and reduce oxidative stress. This review explores the potential roles of yeasts and their derivatives in poultry nutrition. Their effects on productive performance (in broilers, layers, and breeders), carcass traits, immune response, gut health, and oxidative stress are investigated. Full article

Ectomycorrhizal fungi of the genus Tuber (Ascomycota) produce hypogeous ascomata commonly known as truffles. Despite their high ecological and economic importance, a considerable gap of knowledge exists concerning the diversity of Tuber species in the eastern Mediterranean region. In the frame of this study, more than 200 Tuber collections, originating from various regions of Greece, were examined. A new species to science, i.e., Tuber leptodermum, is formally described. Tuber leptodermum is grouped in the Maculatum clade, as revealed by the ITS and LSU rDNA concatenated phylogenetic tree, and appears as sister to T. foetidum. In addition, T. leptodermum exhibits distinct morphoanatomic features: it produces medium-sized, dark-brown ascomata with a thin pseudoparenchymatous peridium, composed of globose-to-angular cells and forms one-to-four-spored asci containing reticulate–alveolate, ellipsoid ascospores with broad meshes. Thirty other phylogenetic species are identified: seven of them (i.e., T. anniae, T. buendiae, T. conchae, T. dryophilum, T. monosporum, T. regianum and T. zambonelliae) constitute new records for the Greek mycobiota, while the presence of five other species is molecularly confirmed for the first time. Moreover, the existence of ten undescribed phylogenetic species is revealed, six of which are reported for the first time in Greece. Several taxonomic and phylogenetic issues and discrepancies in the genus Tuber are discussed in relation to the new findings. Full article

Grapevine trunk diseases (GTDs) are widespread worldwide, causing serious economic losses to the vitiviniculture industry. The etiology of the complex pathogenic mycobiome associated with this group of diseases is critical to implementing appropriate management strategies. Diseased grapevines exhibiting typical GTD symptoms were collected from vineyards in different provinces of Cyprus, resulting in 19 pycnidial isolates. A subsequent multilocus sequence analysis of six genetic loci (ITS, LSU, SSU, b-tub, tef1-a, and rpb2) identified them as Kalmusia variispora, and twelve representative isolates are included in the phylogenetic analyses. According to pathogenicity trials on two-year-old potted vines (cv. Mavro), all tested isolates were pathogenic, exhibiting light to dark brown discoloration and lesions of varying levels, ranging from 4 to 12.3 cm long. The capacity of K. variispora isolates to produce cell-wall-degrading exoenzymes was qualitatively estimated on solid media. Cellulase, pectinase, and laccase production were evident for all the tested isolates, except isolate CBS 151329, where the latter enzyme was undetected. The severity of the symptoms was consistent with the laccase-producing capacity. The present study confirmed the association of K. variispora with grapevines as a pathogen and represents the first description of this ascomycete as a GTD causal agent in Cyprus. This highly virulent species may play a significant role in the GTD complex, and its biological cycle and epidemiology should be further investigated. Full article

Rhizosphere microorganisms effectively exploit nutrient resources within the rhizosphere, while growth-promoting bacteria in this environment play a vital role in regulating soil fertility and enhancing plant health. In this study, we utilized a comprehensive approach that included the isolation, purification, and identification of dominant microorganisms, alongside high-throughput sequencing technology. This methodology was employed to analyze the primary microbial groups and their diversity within the rhizosphere soil of Helichrysum arenarium (L.) Moench in Altay, Xinjiang, China. By isolating bacterial strains from the rhizosphere soil using a dilution coating method, we successfully obtained 43 distinct strains. Subsequently, selective media were employed to screen for growth-promoting characteristics among these isolated strains derived from the rhizosphere soil of H. arenarium (L.) Moench. The results, obtained through high-throughput amplification sequencing, revealed diverse bacterial communities belonging to 35 phyla, 93 orders, 215 families, 324 genera, and 231 species associated with H. arenarium (L.) Moench, as well as fungal communities comprising 14 phyla, 47 orders, 96 families, 204 genera, and 571 species present in the rhizosphere soil. Among these identified communities, Actinobacteriota emerged as the predominant bacterial phylum while Ascomycetes and Mortieromycetes were recognized as the principal fungal phyla found in the rhizospheric soil of H. arenarium (L.) Moench. Analysis of culturable bacteria’s promotion activity within this rhizospheric environment indicated that three strains—S16, S31, and S29—exhibited the highest solubility index for inorganic phosphorus; additionally, the screened strains S7 and S10 demonstrated nitrogen-fixing capabilities. Furthermore, ten strains exhibiting excellent iron-bearing capacities were identified; notably, strain S16 displayed the highest D/d value indicating, its superior iron-bearing capacity. The growth-promoting bacteria were identified as Kocuria rosea, Priestia megaterium, Bacillus mobilis, Bacillus bataviensis, three variants of Bacillus mycoides, Bacillus paramobilis, Bacillus sonorensis, and Alcaligenes faecalis. This study provides a foundational understanding of how microorganisms in the rhizosphere of H. arenarium (L.) Moench influence soil nutrient release and offers valuable insights into enhancing yield and quality cultivation by isolating, screening, and identifying growth-promoting bacteria from rhizosphere soil. Full article

Rice blast caused by the ascomycete fungus Magnaporthe oryzea is one of the most widespread and destructive rice diseases worldwide. The most economical and effective strategy for controlling rice blast is the rational use and promotion of disease-resistant varieties. To enhance disease resistance, it is essential to analyze the resistance levels of rice varieties and the role of resistance (R) genes. To investigate blast resistance, R gene distribution, and their contributions in japonica rice, 287 varieties were evaluated through artificial inoculation. PCR detection was also performed using specific primers for eleven R genes. The results showed that 24.4% of the varieties exhibited moderate resistance (MR), indicating an overall moderate resistance level. The frequency of R genes varied significantly: Pib was the most prevalent (89.2%), followed by Pi5 (73.5%), Pita (62.4%), Pia (54.4%), Pikh (48.4%), Pik (41.1%), Pi9 (35.5%), Pizt (23.7%), Pit (10.8%), and Pi1 (10.5%). No Pigm was detected. Among these, Pik, Pi9, Pizt, and Pita contributed most significantly to disease resistance, with contributions of 42.4%, 38.2%, 38.2%, and 33.5%, respectively. The number of R genes detected in the tested varieties ranged from 0 to 9, with most varieties containing more than three genes. The highest proportion of resistant varieties was observed in those carrying six genes. The most common R gene combinations in resistant varieties were ‘Pib + Pita + Pi5 + Pikh + Pik + Pi9’ and ‘Pizt + Pib + Pita + Pia + Pi5 + Pik + Pi9’. In conclusion, these findings provide valuable insights into the breeding and utilizing blast-resistant japonica rice varieties in Anhui Province. Full article

This study reveals how microbial diversity relates to soil properties in Auricularia heimuer residue–chicken manure composting, presenting sustainable waste recycling solutions. These microbial-straw strategies are adaptable to various agroecological regions, offering flexible residue valorization approaches for local conditions, crops, and resources. This study examined the effects of composting Auricularia heimuer residue and chicken manure at three ratios (6:4, 7:3, 8:2) on soil properties, lignocellulose content, enzyme activity, microbial diversity, and maize growth. The compost was mixed into potting soil at different proportions (0:10 to 10:0). During composting, the temperature remained above 50 °C for more than 14 days, meeting safety and sanitation requirements. The composting process resulted in a pH range of 7–8, a stable moisture content of 60%, a color change from brown to gray-brown, the elimination of unpleasant odors, and the formation of loose aggregates. Lignocellulose content steadily decreased, while lignocellulosic enzyme activity and actinomycete abundance increased, indicating suitability for field application. Compared with the control (CK), total nitrogen, total phosphorus, and total potassium in the soil increased by 57.81–77.91%, 4.5–19.28%, and 301.09–577.2%, respectively. Lignin, cellulose, and hemicellulose increased 50.6–83.49%, 59.6–340.33%, and 150.86–310.5%, respectively. The activities of lignin peroxidase, cellulase, and hemicellulase increased by 9.05–36.31%, 6.7–36.66%, and 37.39–52.16%, respectively. Maize root weight, plant biomass, and root number increased by 120.87–138.59%, 117.83–152.86%, and 29.03–75.81%, respectively. In addition, composting increased the relative abundance of actinomycetes while decreasing the abundance of ascomycetes and ascomycetes. The relative abundance of Sphingomonas and Gemmatimonas increased, whereas pathogenic fungi such as Cladosporium and Fusarium decreased. Compost application also enhanced bacterial and fungal diversity, with bacterial diversity indices ranging from 6.744 to 9.491 (B1), 5.122 to 9.420 (B2), 8.221 to 9.552 (B3), and 6.970 to 9.273 (CK). Fungal diversity indices ranged from 4.811 to 8.583 (B1), 1.964 to 9.160 (B2), 5.170 to 9.022 (B3), and 5.893 to 7.583 (CK). Correlation analysis of soil physicochemical properties, lignocellulose content, enzymes, microbial community composition, and diversity revealed that total nitrogen, total phosphorus, total potassium, and lignocellulose content were the primary drivers of rhizosphere microbial community dynamics. These factors exhibited significant correlations with the dominant bacterial and fungal taxa. Additionally, bacterial and fungal diversity increased with the incorporation of Auricularia heimuer residue. In conclusion, this study elucidates the relationships between microbial diversity and soil properties across different proportions of Auricularia heimuer residue and chicken manure composting, offering alternative strategies for waste recycling and sustainable agricultural development. At present, the production of biobiotics using waste culture microorganisms is still in the laboratory research stage, and no expanded experiments have been carried out. Therefore, how to apply waste bacterial bran to the production of biocontrol biotics on a large scale needs further research. Full article