Journal of Fungi

The characterization of natural fungal diversity impacts our understanding of ecological and evolutionary processes and can lead to novel bioproduct discovery. Russula and Lactarius, both in the order Russulales, represent two large genera of ectomycorrhizal fungi that include edible as well as toxic varieties. Based on morphological and phylogenetic analyses, including nucleotide sequences of the internal transcribed spacer (ITS), the 28S large subunit of ribosomal RNA (LSU), the second largest subunit of RNA polymerase II (RPB2), the ribosomal mitochondrial small subunit (mtSSU), and the translation elongation factor 1-α (TEF1-α) gene sequences, we here describe and illustrate two new species of Russula and one new species of Lactarius from southern China. These three new species are: R. junzifengensis (R. subsect. Virescentinae), R. zonatus (R. subsect. Crassotunicatae), and L. jianyangensis (L. subsect. Zonarii). Full article

Fungi are known as prolific producers of bioactive secondary metabolites with applications across various fields, including infectious diseases, as well as in biological control. However, some of the well-known species are still underexplored. Our current study evaluated the production of secondary metabolites by the entomopathogenic fungus Beauveria neobassiana from Thailand. The fermentation of this fungus in a liquid medium, followed by preparative high-performance liquid chromatography (HPLC) purification, resulted in the isolation of a new tenellin congener, namely pretenellin C (1), together with five known derivatives (2–6). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy in combination with high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). We evaluated the antimicrobial and cytotoxic activities from all isolated compounds, as well as their inhibitory properties on biofilm formation by Staphylococcus aureus. Generally, tenellins displayed varying antibiofilm and cytotoxic effects, allowing us to propose preliminary structure-activity relationships (SARs). Among the tested compounds, prototenellin D (2) exhibited the most prominent antibiofilm activity, while its 2-pyridone congener, tenellin (4), demonstrated potent cytotoxic activity against all tested cell lines. Given the fact that the biological activities of the tenellins have so far been neglected in the past, our study could provide a good starting point to establish more concise structure-activity relationships in the near future. Full article

The endoparasitic fungus Hirsutella rhossiliensis is an important biocontrol agent of cyst nematodes in nature. To determine the potential parasitism of the fungus on a non-natural host, the pinewood nematode (Bursaphelenchus xylophilus) living in pine trees and the endophytic ability of the fungus on plants, in this paper, we first constructed and utilized a green fluorescent protein (GFP)-tagged H. rhossiliensis HR02 transformant to observe the fungal infection process on B. xylophilus and its colonization on Arabidopsis roots. Then, we compared the fungal parasitism on three species of nematodes with different lifestyles, and we found that the fungal parasitism is correlated with nematode species and stages. The parasitic effect of H. rhossiliensis on adults of B. xylophilus is similar to that on second-stage juveniles (J2) of the root-knot nematode Meloidogyne incognita after 24 h of inoculation, although the virulence of the fungus to second-stage juveniles of M. incognita is stronger than that to those of B. xylophilus and Caenorhabditis elegans. Moreover, the endophytism of H. rhossiliensis was confirmed. By applying an appropriate concentration of H. rhossiliensis conidial suspension (5 × 10⁶ spores/mL) in rhizosphere soil, it was found that the endophytic fungus can promote A. thaliana growth and reproduction, as well as improve host resistance against M. incognita. Our results provide a deeper understanding of the fungus H. rhossiliensis as a promising biocontrol agent against plant-parasitic nematodes. Full article

A review of selected studies on fungal endophytes confirms the paucity of Basidiomycota and basal fungi, with almost 90% attributed to Ascomycota. Reasons for the low number of Basidiomycota and basal fungi, including the Chytridiomycota, Mucoromycota, and Mortierellomycota, are advanced, including isolation procedure and media, incubation period and the slow growth of basidiomycetes, the identification of non-sporulating isolates, endophyte competition, and fungus–host interactions. We compare the detection of endophytes through culture-dependent methods and culture-independent methods, the role of fungi on senescence of the host plant, and next-generation studies. Full article

Flower blight caused by Neopestalotiopsis clavispora is an emerging disease of flamingo flower (Anthurium andraeanum Lind.) that negatively impacts flower production. The use of rhizosphere fungi as biocontrol agents is an alternative way to control this disease instead of using synthetic fungicides. This research aimed to screen the potential of rhizosphere fungi, Trichoderma spp., with diverse antifungal abilities to control N. clavispora and to reduce flower blight in flamingo flowers. A total of ten isolates were tested against N. clavispora by dual culture assay, and T1-02 was found to be the most effective isolate against N. clavispora, with inhibition of 78.21%. Morphology and molecular phylogeny of multiple DNA sequences of the genes, the internal transcribed spacer (ITS), translation elongation factor 1-α (tef1-α), and RNA polymerase 2 (rpb2) identified isolate T1-02 as Trichoderma virens. Sealed plate method revealed T. virens T1-02 produced volatile antifungal compounds (VOCs) against N. clavispora, with inhibition of 51.28%. Solid-phase microextraction (SPME) was applied to trap volatiles, and GC/MS profiling showed VOCs emitted from T. virens T1-02 contained a sesquiterpene antifungal compound—germacrene D. The pre-colonized plate method showed that T. virens T1-02 aggressively colonized in tested plates with inhibition of 100% against N. clavispora, and microscopy revealed direct parasitism onto fungal hyphae. Furthermore, the application of T. virens T1-02 spore suspension reduced the disease severity index (DSI) of flower blight in flamingo flowers. Based on the results from this study, T. virens T1-02 displays multiple antagonistic mechanisms and has the potential ability to control flower blight of flamingo flowers caused by N. clavispora. Full article

It is generally believed that mycorrhiza is a microecosystem composed of mycorrhizal fungi, host plants and other microscopic organisms. The mycorrhiza of Rhododendron dauricum is more complex and the diverse morphology of our investigated results displays both typical ericoid mycorrhizal characteristics and ectomycorrhizal traits. The characteristics of ectendoomycorrhiza, where mycelial invade from the outside into the root cells, have also been observed. In order to further clarify the mycorrhizal fungi members and other fungal communities of R. dauricum mycorrhiza, and explore the effects of vegetation and soil biological factors on their community structure, we selected two woodlands in the northeast of China as samples—one is a mixed forest of R. dauricum and Quercus mongolica, and the other a mixed forest of R. dauricum, Q. mongolica, and Pinus densiflor. The sampling time was during the local growing season, from June to September. High-throughput sequencing yielded a total of 3020 fungal amplicon sequence variants (ASVs), which were based on sequencing of the internal transcribed spacer ribosomal RNA (ITS rRNA) via the Illumina NovaSeq platform. In the different habitats of R. dauricum, there are differences in the diversity of fungi obtained from mycorrhizal niches, and specifically the mycorrhizal fungal community structure in the complex vegetation of mixed forests, where R. dauricum is found, exhibits greater stability, with relatively minor changes over time. Soil fungi are identified as the primary source of fungi within the mycorrhizal niche, and the abundance of mycorrhizal fungi from mycorrhizal niches in R. dauricum is significantly influenced by soil pH, organic matter, and available nitrogen. The relationship between soil fungi and mycorrhizal fungi from mycorrhizal niches is simultaneously found to be intricate, while the genus Hydnellum emerges as a central genus among mycorrhizal fungi from mycorrhizal niches. However, there is currently a substantial gap in the foundational research of this genus, including the fact that mycorrhizal fungi from mycorrhizal niches have, compared to fungi present in the soil, proven to be more sensitive to changes in soil moisture. Full article

Mucormycosis is known to be a rare opportunistic infection caused by fungal organisms belonging to the Mucorales order, which includes the Syncephalastrum species. These moulds are rarely involved in clinical diseases and are generally seen as contaminants in clinical laboratories. However, in recent years, case reports of human infections due to Syncephalastrum have increased, especially in immunocompromised hosts. In this study, we described two new Syncephalastrum species, which were isolated from human nails and sputum samples from two different patients. We used several methods for genomic and phenotypic characterisation. The phenotypic analysis relied on the morphological features, analysed both by optical and scanning electron microscopy. We used matrix-assisted laser desorption–ionization time-of-flight mass spectrometry, energy-dispersive X-ray spectroscopy, and BiologTM technology to characterise the proteomic, chemical mapping, and carbon source assimilation profiles, respectively. The genomic analysis relied on a multilocus DNA sequence analysis of the rRNA internal transcribed spacers and D1/D2 large subunit domains, fragments of the translation elongation factor-1 alpha, and the β-tubulin genes. The two novel species in the genus Syncephalastrum, namely S. massiliense PMMF0073 and S. timoneanum PMMF0107, presented a similar morphology: irregular branched and aseptate hyphae with ribbon-like aspects and terminal vesicles at the apices all surrounded by cylindrical merosporangia. However, each species displayed distinct phenotypic and genotypic features. For example, S. timoneanum PMMF0107 was able to assimilate more carbon sources than S. massiliense PMMF0073, such as adonitol, α-methyl-D-glucoside, trehalose, turanose, succinic acid mono-methyl ester, and alaninamide. The polyphasic approach, combining the results of complementary phenotypic and genomic assays, was instrumental for describing and characterising these two new Syncephalastrum species. Full article

The oleaginous yeast Yarrowia lipolytica is a prominent subject of biorefinery research due to its exceptional performance in oil production, exogenous protein secretion, and utilization of various inexpensive carbon sources. Many CRISPR/Cas9 genome-editing systems have been developed for Y. lipolytica to meet the high demand for metabolic engineering studies. However, these systems often necessitate an additional outgrowth step to achieve high gene editing efficiency. In this study, we introduced the eSpCas9 protein, derived from the Streptococcus pyogenes Cas9(SpCas9) protein, into the Y. lipolytica genome to enhance gene editing efficiency and fidelity, and subsequently explored the optimal expression level of eSpCas9 gene by utilizing different promoters and selecting various growth periods for yeast transformation. The results demonstrated that the integrated eSpCas9 gene editing system significantly enhanced gene editing efficiency, increasing from 16.61% to 86.09% on TRP1 and from 33.61% to 95.19% on LIP2, all without the need for a time-consuming outgrowth step. Furthermore, growth curves and dilution assays indicated that the consistent expression of eSpCas9 protein slightly suppressed the growth of Y. lipolytica, revealing that strong inducible promoters may be a potential avenue for future research. This work simplifies the gene editing process in Y. lipolytica, thus advancing its potential as a natural product synthesis chassis and providing valuable insights for other comparable microorganisms. Full article

Sporisorium reilianum, the causal agent of sorghum (Sorghum bicolor (L.) Moench) head smut, is present in most sorghum-producing regions. This seed replacement fungal disease can reduce yield by up to 80% in severely infected fields. Management of this disease can be challenging due to the appearance of different pathotypes within the pathogenic population. In this research, the genetic variability and pathogenicity of isolates collected from five Texas Counties was conducted. Due to the lack of available space, 21 out of 32 sequenced isolates were selected and evaluated for virulence patterns on the six sorghum differentials, Tx7078, BTx635, SC170-6-17 (TAM2571), SA281 (Early Hegari), Tx414, and BTx643. The results reveal the occurrence of a new pathotype, 1A, and four previously documented US pathotypes when the 21 isolates were evaluated for virulence patterns on the differentials. The most prevalent was pathotype 5, which was recovered from Brazos, Hidalgo, Nueces, and Willacy Counties, Texas. This pathotype was followed by 1A and 6 in frequency of recovery. Pathotype 4 was identified only from isolates collected from Hidalgo County, while pathotype 1 was from Burleson County, Texas. It appeared that the previous US head smut pathotypes (2 and 3) are no longer common, and the new pathotypes, 1A, 5, and 6, are now predominant. The phylogenetic tree constructed from the single-nucleotide polymorphism (SNP) data through the neighbor-joining method showed high genetic diversity among the tested isolates. Some of the diverse clades among the tested isolates were independent of their sampled locations. Notably, HS37, HS49, and HS65 formed a clade and were classified as 1A in the virulence study, while HS 61 and HS 66, which were collected from Nueces County, were grouped and identified as pathotype 5. Full article

Objectives: Invasive fungal spondylodiscitis (IFSD) is rare and could be lethal in certain circumstances. The previous literature revealed limited data concerning its outcomes. This study aimed to establish a risk-scoring system to predict the one-year mortality rate of this disease. Methods: A total of 53 patients from a multi-centered database in Taiwan were included in this study. All the clinicopathological and laboratory data were retrospectively analyzed. Variables strongly related to one-year mortality were identified using a multivariate Cox proportional hazards model. A receiver operating characteristic (ROC) curve was used to express the performance of our IFSD scoring model. Results: Five strong predictors were included in the IFSD score: predisposing immunocompromised state, the initial presentation of either radiculopathy or myelopathy, initial laboratory findings of WBC > 12.0 or <0.4 10³/µL, hemoglobin < 8 g/dL, and evidence of candidemia. One-year mortality rates for patients with IFSD scores of 0, 1, 2, 3, and 4 were 0%, 16.7%, 56.3%, 72.7%, and 100%, respectively. The area under the curve of the ROC curve was 0.823. Conclusions: We developed a practical scoring model with easily obtained demographic, clinical, and laboratory parameters to predict the probability of one-year mortality in patients with IFSD. However, more large-scale and international validations would be necessary before this scoring model is commonly used. Full article

We have found 117 taxa of lichenicolous fungi in the studied area. In this paper, we describe five taxa: Arthonia boomiana on Nephromopsis chlorophylla, Lawalreea burgaziana on Platismatia glauca, Pronectria scrobiculatae on Lobarina scrobiculata, Trichonectria parmeliellae on Parmeliella testacea and Trichonectria rubefaciens ssp. cryptoramalinae on Ramalina. Furthermore, the next records are interesting chorologically from the Iberian Peninsula: Arthophacopsis parmeliarum, Catillaria lobariicola, Lichenopuccinia poeltii, Myxotrichum bicolor, Nanostictis christiansenii, Niesslia lobariae, Opegrpaha sphaerophoricola, Pronectria fragmospora, Rhymbocarpus aggregatus, R. neglectus, and Tremella cetrariicola. Full article

Agaricus belongs to Agaricaceae and is one of the most well-known macrofungi, with many edible species. More than 300 Agaricus specimens were collected during a three-year macrofungal resource field investigation in Northeast China. Based on morphological observations and multi-gene (ITS + nrLSU + tef1-a) phylogenetic analyses, six new Agaricus species, i.e., Agaricus aurantipileatus, A. daqinggouensis, A. floccularis, A. griseopileatus, A. sinoagrocyboides, and A. velutinosus, were discovered. These new species belong to four sections within different subgenera: A. (subg. Agaricus) sect. Agaricus, A. (subg. Flavoagaricus) sect. Arvenses, A. (subg. Minores) sect. Minores, and A. (subg. Pseudochitonia) sect. Xanthodermatei. Morphological descriptions, line illustrations, and basidiomata photographs of these new species are provided, and their differences from similar species are discussed. Full article

Nitric oxide (NO) is a natural reactive nitrogen species (RNS) that alters proteins, DNA, and lipids and damages biological activities. Although microorganisms respond to and detoxify NO, the regulation of the cellular metabolic mechanisms that cause cells to tolerate RNS toxicity is not completely understood. We found that the proline and arginine auxotrophic proA5 and argB2 mutants of the fungus Aspergillus nidulans require more arginine and proline for normal growth under RNS stress that starves cells by accumulating fewer amino acids. Fungal transcriptomes indicated that RNS stress upregulates the expression of the biosynthetic genes required for global amino acids, including proline and arginine. A mutant of the gene disruptant, cpcA, which encodes the transcriptional regulation of the cross-pathway control of general amino acid synthesis, did not induce these genes, and cells accumulated fewer amino acids under RNS stress. These results indicated a novel function of CpcA in the cellular response to RNS stress, which is mediated through amino acid starvation and induces the transcription of genes for general amino acid synthesis. Since CpcA also controls organic acid biosynthesis, impaired intermediates of such biosynthesis might starve cells of amino acids. These findings revealed the importance of the mechanism regulating amino acid homeostasis for fungal responses to and survival under RNS stress. Full article

Saprolegniosis is a major destructive disease in freshwater aquaculture. The destructive economic impact of saprolegniosis on freshwater aquaculture necessitates further study on the range of Saprolegnia species within Atlantic salmon fish farms. This study undertook a thorough analysis of a total of 412 oomycete and fungal isolates that were successfully cultured and sequenced from 14 aquaculture sites in Scotland across a two-year sampling period. An ITS phylogenetic analysis of all isolates was performed according to whether they were isolated from fish or water samples and during enzootic or epizootic periods. Several genera of oomycetes were isolated from sampling sites, including Achlya, Leptolegnia, Phytophthora, and Pythium, but by far the most prevalent was Saprolegnia, accounting for 66% of all oomycetes isolated. An analysis of the ITS region of Saprolegnia parasitica showed five distinct phylotypes (S2–S6); S1 was not isolated from any site. Phylotype S2 was the most common and most widely distributed phylotype, being found at 12 of the 14 sampling sites. S2 was overwhelmingly sampled from fish (93.5%) and made up 91.1% of all S. parasitica phylotypes sampled during epizootics, as well as 67.2% of all Saprolegnia. This study indicates that a single phylotype may be responsible for Saprolegnia outbreaks in Atlantic salmon fish farms, and that water sampling and spore counts alone may be insufficient to predict Saprolegnia outbreaks in freshwater aquaculture. Full article

This is the first record of the fungus Flavocillium subprimulinum in Mexico. The isolate was taxonomically characterised and cultured in potato dextrose broth (PDB), Czapek–Dox broth (CzDoxB), and sweet potato dextrose broth (SPDB) to obtain its filtrates (FLCF). The nematocidal activity (NA) of three FLCF concentrations was assessed against Haemonchus contortus L3. Protease activity (PA) was assessed with SDS-PAGE, followed by a zymogram. The NA of the FLCF reached 94.43% in PDB and 95.82% in CzDoxB, respectively, at 100 mg/mL. Lower mortality (64%) was found in SPDB at 100 mg/mL. SDS-PAGE showed bands (in PBS) of ~25, ~40, and ~55 kDa. The zymogram showed protein bands (PBs) with PA in the media, including PBs of ~14, ~40, and ~55 kDa. This study establishes the basis for exploring the potential use of this fungus against H. contortus, which is considered the most pathogenic parasite affecting lambs. Full article

Three new wood-inhabiting fungal species, Cerioporus yunnanensis, Perenniporiopsis sinensis, and Sarcoporia yunnanensis, are proposed based on a combination of the morphological features and molecular evidence. Cerioporus yunnanensis is characterized by the pileate basidiomata having a fawn brown to black pileal surface, a dimitic hyphal system with clamped generative hyphae, and the presence of the fusoid cystidioles and cylindrical basidiospores (9–12.5 × 3.5–5 µm). Perenniporiopsis sinensis is distinct from the osseous pileus with verrucose, an orange-yellow to dark reddish-brown pileal surface with a cream margin, a trimitic hyphal system with clamped generative hyphae, and the presence of the fusiform cystidioles and ellipsoid basidiospores (9–11 × 5.5–6.5 µm). Sarcoporia yunnanensis is typical of the pileate basidiomata with a salmon to reddish-brown pileal surface, a monomitic hyphal system with clamped generative hyphae, and the presence of the ellipsoid basidiospores (4–5.5 × 2.5–4 µm). Sequences of ITS + nLSU + mt-SSU + TEF1 + RPB1 + RPB2 genes were used for the phylogenetic analyses using maximum likelihood, maximum parsimony, and Bayesian inference methods. The multiple genes with six loci analysis showed that the three new species nested within the order Polyporales, in which C. yunnanensis and P. sinensis nested into the family Polyporaceae, and S. yunnanensis grouped into the family Sarcoporiaceae. Full article

Plant defensins are a large family of small cationic proteins with diverse functions and mechanisms of action, most of which assert antifungal activity against a broad spectrum of fungi. The partial mechanism of action has been resolved for a small number of members of plant defensins, and studies have revealed that many act by more than one mechanism. The plant defensin Ppdef1 has a unique sequence and long loop 5 with fungicidal activity against a range of human fungal pathogens, but little is known about its mechanism of action. We screened the S. cerevisiae non-essential gene deletion library and identified the involvement of the mitochondria in the mechanism of action of Ppdef1. Further analysis revealed that the hyperpolarisation of the mitochondrial membrane potential (MMP) activates ROS production, vacuolar fusion and cell death and is an important step in the mechanism of action of Ppdef1, and it is likely that a similar mechanism acts in Trichophyton rubrum. Full article

Brown leaf spot disease caused by Alternaria spp. is among the most common diseases of potato crops. Typical brown spot symptoms were observed in commercial potato-cultivation areas of northern Korea from June to August 2020–2021. In total, 68 isolates were collected, and based on sequence analysis of the internal transcribed spacer (ITS) region, the collected isolates were identified as Alternaria spp. (80.9%). Phylogenetic analysis revealed that a majority of these isolates clustered within a clade that included A. alternata. Additionally, the ITS region and rpb2 yielded the most informative sequences for the identification of A. alternata. Pathogenicity tests confirmed that the collected pathogens elicited symptoms identical to those observed in the field. In pathogenicity tests performed on seven commercial cultivars, the pathogens exhibited strong virulence in both wound and non-wound inoculations. Among the cultivars tested, Arirang-1ho, Arirang-2ho, and Golden Ball were resistant to the pathogens. Furthermore, among the fungicides tested in vitro, mancozeb and difenoconazole were found to be effective for inhibiting mycelial growth. In summary, our findings suggest that A. alternata plays a critical role in leaf disease in potato-growing regions and emphasise the necessity of continuous monitoring and management to protect against this disease in Korea. Full article

Among pollution remediation technologies, advanced oxidation processes (AOPs) are genuinely efficient since they are based on the production of strong, non-selective oxidants, mainly hydroxyl radicals (·OH), by a set of physicochemical methods. The biological counterparts of AOPs, which may be referred to as advanced bio-oxidation processes (ABOPs), have begun to be investigated since the mechanisms of induction of ·OH production in fungi are known. To contribute to the development of ABOPs, advanced oxidation of a wide number of dyes by the white-rot fungus Pleurotus eryngii, via a quinone redox cycling (QRC) process based on Fenton’s reagent formation, has been described for the first time. The fungus was incubated with 2,6-dimethoxy-1,4-benzoquinone (DBQ) and Fe³⁺-oxalate, with and without Mn²⁺, leading to different ·OH production rates, around twice higher with Mn²⁺. Thanks to this process, the degradative capacity of the fungus increased, not only oxidising dyes it was not otherwise able to, but also increasing the decolorization rate of 20 dyes by more than 7 times in Mn²⁺ incubations. In terms of process efficacy, it is noteworthy that with Mn²⁺ the degradation of the dyes reached values of 90–100% in 2–4 h, which are like those described in some AOPs based on the Fenton reaction. Full article