Diversity and taxonomy of Chaetomium and chaetomium-like fungi from indoor environments

Sunken Riches: Ascomycete Diversity in the Western Mediterranean Coast through Direct Plating and Flocculation, and Description of Four New Taxa

The Mediterranean Sea stands out as a hotspot of biodiversity, whose fungal composition remains underexplored. Marine sediments represent the most diverse substrate; however, the challenge of recovering fungi in culture hinders the precise identification of this diversity. Concentration techniques like skimmed milk flocculation (SMF) could represent a suitable solution. Here, we compare the effectiveness in recovering filamentous ascomycetes of direct plating and SMF in combination with three culture media and two incubation temperatures, and we describe the fungal diversity detected in marine sediments. Sediments were collected at different depths on two beaches (Miracle and Arrabassada) on the Spanish western Mediterranean coast between 2021 and 2022. We recovered 362 strains, and after a morphological selection, 188 were identified primarily with the LSU and ITS barcodes, representing 54 genera and 94 species. Aspergillus, Penicillium, and Scedosporium were the most common genera, with different percentages of abundance between both beaches. Arrabassada Beach was more heterogeneous, with 42 genera representing 60 species (Miracle Beach, 28 genera and 54 species). Although most species were recovered with direct plating (70 species), 20 species were exclusively obtained using SMF as a sample pre-treatment, improving our ability to detect fungi in culture. In addition, we propose three new species in the genera Exophiala, Nigrocephalum, and Queenslandipenidiella, and a fourth representing the novel genus Schizochlamydosporiella. We concluded that SMF is a useful technique that, in combination with direct plating, including different culture media and incubation temperatures, improves the chance of recovering marine fungal communities in culture-dependent studies.

Anti-inflammatory Polyketides from an Endophytic Fungus Chaetomium sp. UJN-EF006 of Vaccinium bracteatum

Seven new polyketides including three chromone derivatives (1-3) and four linear ones incorporating a tetrahydrofuran ring (4-7), along with three known compounds (8-10), were obtained from the fermentation of an endophytic fungus (Chaetomium sp. UJN-EF006) isolated from the leaves of Vaccinium bracteatum. The structures of these fungal metabolites have been elucidated by spectroscopic means including MS, NMR and electronic circular dichroism. A preliminary anti-inflammatory screening with the lipopolysaccharide (LPS) induced RAW264.7 cell model revealed moderate NO production inhibitory activity for compounds 1 and 4. In addition, the expression of three LPS-induced inflammatory factors IL-6, iNOS and COX-2 was also blocked by 1 and 4.

A novel enrofloxacin-degrading fungus, Humicola sp. KC0924g, isolated from the rhizosphere sediment of the submerged macrophyte Vallisneria spiralis L

A novel enrofloxacin-degrading fungus was isolated from a rhizosphere sediment of the submerged macrophyte Vallisneria spiralis L.. The isolate, designated KC0924g, was identified as a member of the genus Humicola based on morphological characteristics and tandem conserved sequence analysis. The optimal temperature and pH for enrofloxacin degradation by strain KC0924g were 28 °C and 9.0, respectively. Under such condition, 98.2% of enrofloxacin with an initial concentration of 1 mg L-1 was degraded after 72 h of incubation, with nine possible degradation products identified. Four different metabolic pathways were proposed, which were initiated by cleavage of the piperazine moiety, hydroxylation of the aromatic ring, oxidative decarboxylation, or defluorination. In addition to enrofloxacin, strain KC0924g also degraded other fluoroquinolone antibiotics (ciprofloxacin, norfloxacin, and ofloxacin), malachite green (an illegal additive in aquaculture), and leucomalachite green. Pretreatment of cells of strain KC0924g with Cu2+ accelerated ENR degradation. Furthermore, it was speculated that a flavin-dependent monooxygenase was involved in ENR degradation, based on the increased transcriptional levels of these two genes after Cu2+ induction. This work enriches strain resources for enrofloxacin remediation and, more importantly, would facilitate studies on the molecular mechanism of ENR degradation with degradation-related transcriptome available.

Two new species of Sordariomycetes (Chaetomiaceae and Nectriaceae) from China

Rich and diverse fungal species occur in different habitats on the earth. Many new taxa are being reported and described in increasing numbers with the advent of molecular phylogenetics. However, there are still a number of unknown fungi that have not yet been discovered and described. During a survey of fungal diversity in different habitats in China, we identified and proposed two new species, based on the morphology and multi-gene phylogenetic analyses. Herein, we report the descriptions, illustrations and molecular phylogeny of the two new species, Bisifusariumkeratinophilumsp. nov. and Ovatosporasinensissp. nov.

Identification and application of an endophytic fungus Arcopilus aureus from Panax notoginseng against crop fungal disease

Endophytic fungi are important microbial resources for developing novel antibacterial and antifungal drugs to prevent and control crop diseases. Panax notoginseng has been used as a Chinese medicinal herb for a long time, as it has various bioactivities. However, information on endophytic fungi isolated from Panax notoginseng is rare. In this study, an endophytic fungus known as SQGX-6, which was later identified as the golden hair fungus Arcopilus aureus, was isolated from Panax notoginseng. SQGX-6 was extracted using ethyl acetate, and the active components of the fungus were identified using ultra-performance liquid chromatography-mass spectrometry (UHPLC-MS). The antifungal and antioxidant activities of the extract were determined and evaluated in vitro and in vivo. SQGX-6 and its extract inhibited the growth of Corn stalk rot (Fusarium graminearum), Corn southern leaf blight (Helminthosporium maydis), and Tomato gray mold (Botrytis cinerea) in vitro. The free radical scavenging rates for 2,2-Diphenyl-1-pyridinyl hydrazide (DPPH) radical scavenging activity, 3-Ethylbenzothiazoline-6-Sulfonic Acid Radical scavenging (ABTS) activity were also downregulated by the SQGX-6 extract. In vivo, the SQGX-6 extract inhibited the mycelial growth rates of the three aforementioned fungi and downregulated malondialdehyde (MDA) content and upregulated peroxidase (POD) and phenylalanine ammonia-lyase (PAL) content in fruits, leading to significant reduction in damage to cherry tomatoes caused by Botrytis cinerea. UHPLC-MS was performed to identify various active substances, including Alkaloids, Azoles, Benzofurans, Coumarins, Flavonoids, Organic acids, Phenols, and plant growth regulators contained in the extract. These results suggested that the endophytic fungus SQGX-6 of Panax notoginseng and its extract have excellent antifungal and antioxidant activities, and thus, it is an important microbial resource for the developing novel drugs against plant fungal infections.

Degradation Potential of Xerophilic and Xerotolerant Fungi Contaminating Historic Canvas Paintings

Fungi are important contaminants of historic canvas paintings worldwide. They can grow on both sides of the canvas and decompose various components of the paintings. They excrete pigments and acids that change the visual appearance of the paintings and weaken their structure, leading to flaking and cracking. With the aim of recognizing the most dangerous fungal species to the integrity and stability of paintings, we studied 55 recently isolated and identified strains from historic paintings or depositories, including 46 species from 16 genera. The fungi were categorized as xero/halotolerant or xero/halophilic based on their preference for solutes (glycerol or NaCl) that lower the water activity (aw) of the medium. Accordingly, the aw value of all further test media had to be adjusted to allow the growth of xero/halophilic species. The isolates were tested for growth at 15, 24 °C and 37 °C. The biodeterioration potential of the fungi was evaluated by screening their acidification properties, their ability to excrete pigments and their enzymatic activities, which were selected based on the available nutrients in paintings on canvas. A DNase test was performed to determine whether the selected fungi could utilize DNA of dead microbial cells that may be covering surfaces of the painting. The sequestration of Fe, which is made available through the production of siderophores, was also tested. The ability to degrade aromatic and aliphatic substrates was investigated to consider the potential degradation of synthetic restoration materials. Xerotolerant and moderately xerophilic species showed a broader spectrum of enzymatic activities than obligate xerophilic species: urease, β-glucosidase, and esterase predominated, while obligate xerophiles mostly exhibited β-glucosidase, DNase, and urease activity. Xerotolerant and moderately xerophilic species with the highest degradation potential belong to the genus Penicillium, while Aspergillus penicillioides and A. salinicola represent obligately xerophilic species with the most diverse degradation potential in low aw environments.

Ascus function: From squirt guns to ooze tubes

Unlike the mechanism of ballistospore discharge, which was not solved until the 1980s, the operation of asci as pressurized squirt guns is relatively straightforward and was understood in the nineteenth century. Since then, mycologists have sought to understand how structural adaptations to asci have allowed the ascomycetes to expel spores of different shapes and sizes over distances ranging from a few millimeters to tens of centimeters. These modifications include the use of valves at the tips of asci that maintain ascus pressure and expel spores at the highest speeds, and gelatinous appendages that connect spores after release and create larger projectiles with greater momentum than single spores. Clever experiments in the twentieth century coupled with meticulous microscopic studies led investigators to understand how asci with complicated apical structures worked and mathematical models produced estimates of launch speeds. With the recent application of high-speed video microscopy, these inferences about ascus function have been tested by imaging the motion of spores on a microsecond timescale. These experiments have established that ascospore discharge is the fastest fungal movement and is among the fastest movements in biology. Beginning with the history of the study of asci, this review article explains how asci are pressurized, how spores are released, and how far spores travel after their release. We also consider the efficiency of ascospore discharge relative to the mechanism of ballistospore discharge and examine the way that the squirt gun mechanism has limited the morphological diversity of ascomycete fruit bodies.

A conceptual framework for nomenclatural stability and validity of medically important fungi: a proposed global consensus guideline for fungal name changes supported by ABP, ASM, CLSI, ECMM, ESCMID-EFISG, EUCAST-AFST, FDLC, IDSA, ISHAM, MMSA, and MSGERC

The rapid pace of name changes of medically important fungi is creating challenges for clinical laboratories and clinicians involved in patient care. We describe two sources of name change which have different drivers, at the species versus the genus level. Some suggestions are made here to reduce the number of name changes. We urge taxonomists to provide diagnostic markers of taxonomic novelties. Given the instability of phylogenetic trees due to variable taxon sampling, we advocate to maintain genera at the largest possible size. Reporting of identified species in complexes or series should where possible comprise both the name of the overarching species and that of the molecular sibling, often cryptic species. Because the use of different names for the same species will be unavoidable for many years to come, an open access online database of the names of all medically important fungi, with proper nomenclatural designation and synonymy, is essential. We further recommend that while taxonomic discovery continues, the adaptation of new name changes by clinical laboratories and clinicians be reviewed routinely by a standing committee for validation and stability over time, with reference to an open access database, wherein reasons for changes are listed in a transparent way.

Botryorhodines K and L, two new cytotoxic depsidones from a fungus of the genus Arcopilus

Botryorhodines K (1) and L (2), two new depsidone derivatives, along with one known metabolite, 4-O-demethylbarbatic acid (3), were isolated from the culture extract of a fungus of the genus Arcopilus. The structures of 1‒3 were determined by the analysis of NMR and MS spectral data and the absolute configuration of 1 was established by single-crystal X-ray diffraction analysis. Compounds 1 and 2 showed antimicrobial activity against Gram-positive bacteria and cytotoxicity against murine leukemia P388 cells.

Addition of Five Novel Fungal Flora to the Xylariomycetidae (Sordariomycetes, Ascomycota) in Northern Thailand

The deviation of conventional fungal niches is an important factor in the implications of hidden fungal diversity and global fungal numbers. The Xylariomycetidae (Sordariomycetes, Ascomycota), which is also referred to as xylarialean taxa, has a wide range of species that demonstrate a high degree of variation in their stromatic characteristics, showing either conspicuous or inconspicuous forms. In this study, samples were collected while focusing on temporal and spatial parameters and substrate characteristics. Based on internal transcribed spacer (ITS), 28S large subunit rDNA (LSU), RNA polymerase II second largest subunit (RPB2), and β-tubulin (TUB2) multigene phylogeny and morphology, five new species are introduced as Muscodor brunneascosporus, M. lamphunensis (Xylariaceae), Nigropunctata hydei, N. saccata (Incertae sedis), and Xenoanthostomella parvispora (Gyrotrichaceae). Plant substrates in the early stages of decay and attached to the host were feasible sample niches, with an emphasis on the collection of inconspicuous, hidden xylarialean species. The appearance of inconspicuous saprobic xylarialean forms during the rainy season may be linked to the change in nutritional mode, from endophytic mode during the dry season to saprobic in the wet. Therefore, it would be fascinating to concentrate future research on how seasonal fluctuations affect nutritional mode shifts, especially in northern Thailand, which would provide the optimal spatial characteristics. In order to establish a comprehensive linkage between endophytic and saprobic modes, it is imperative to have a substantial representation of endophytic isolate sequences resembling inconspicuous xylariaceous fungi within publicly accessible databases.

Evaluation of MALDI-TOF MS, sequencing of D2 LSU rRNA and internal transcribed spacer regions (ITS) for the identification of filamentous fungi isolated from a pharmaceutical facility

The identification of filamentous fungi through culture characterization may be hampered by phenotypic variability. Information obtained from the identification of microorganisms are important for investigation of sources of contamination of a product or process. The aim of this study was to identify filamentous fungal strains (n = 50) isolated from a pharmaceutical facility by using Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), as well as D2 domain of the large-subunit (LSU) ribosomal RNA gene and internal transcribed spacer regions (ITS) sequencing. MALDI-TOF MS system only identified five strains at the species level, while 45 were not identified. The analysis through GenBank allowed the identification of up to 19 strains at the species level, while MycoBank allowed the identification of up to nine strains at the species level. The databases identified up to 11 genera: Penicillium, Aspergillus, Cladosporium, Chaetomium, Coniochaeta, Curvularia, Diaporthe, Fusarium, Trichoderma, Rhizopus and Microdochium. MALDI-TOF MS showed an insufficient database to identify the species of fungi. DNA sequencing was the best methodology to identify to the genus level but was unable to differentiate between closely related species. Therefore further methods for the identification of filamentous fungi from pharmaceutical areas at species level need to be developed.

Chemical diversity and biological activities of specialized metabolites from the genus Chaetomium: 2013-2022

Chaetomium (Chaetomiaceae), a large fungal genus consisting of at least 400 species, has been acknowledged as a promising resource for the exploration of novel compounds with potential bioactivities. Over the past decades, emerging chemical and biological investigations have suggested the structural diversity and extensive potent bioactivity of the specialized metabolites in the Chaetomium species. To date, over 500 compounds with diverse chemical types have been isolated and identified from this genus, including azaphilones, cytochalasans, pyrones, alkaloids, diketopiperazines, anthraquinones, polyketides, and steroids. Biological research has indicated that these compounds possess a broad range of bioactivities, including antitumor, anti-inflammatory, antimicrobial, antioxidant, enzyme inhibitory, phytotoxic, and plant growth inhibitory activities. This paper summarizes current knowledge referring to the chemical structure, biological activity, and pharmacologic potency of the specialized metabolites in the Chaetomium species from 2013 to 2022, which might provide insights for the exploration and utilization of bioactive compounds in this genus both in the scientific field and pharmaceutical industry.

Amesia hispanica sp. nov., Producer of the Antifungal Class of Antibiotics Dactylfungins

During a study of the diversity of soilborne fungi from Spain, a strain belonging to the family Chaetomiaceae (Sordariales) was isolated. The multigene phylogenetic inference using five DNA loci showed that this strain represents an undescribed species of the genus Amesia, herein introduced as A. hispanica sp. nov. Investigation of its secondary metabolome led to the isolation of two new derivatives (2 and 3) of the known antifungal antibiotic dactylfungin A (1), together with the known compound cochliodinol (4). The planar structures of 1-4 were determined by ultrahigh performance liquid chromatography coupled with diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IM-MS/MS) and extensive 1D and 2D nuclear magnetic resonance (NMR) spectroscopy after isolation by HPLC. All isolated secondary metabolites were tested for their antimicrobial and cytotoxic activities. Dactylfungin A (1) showed selective and strong antifungal activity against some of the tested human pathogens (Aspergillus fumigatus and Cryptococcus neoformans). The additional hydroxyl group in 2 resulted in the loss of activity against C. neoformans but still retained the inhibition of As. fumigatus in a lower concentration than that of the respective control, without showing any cytotoxic effects. In contrast, 25″-dehydroxy-dactylfungin A (3) exhibited improved activity against yeasts (Schizosaccharomyces pombe and Rhodotorula glutinis) than 1 and 2, but resulted in the appearance of slight cytotoxicity. The present study exemplifies how even in a well-studied taxonomic group such as the Chaetomiaceae, the investigation of novel taxa still brings chemistry novelty, as demonstrated in this first report of this antibiotic class for chaetomiaceous and sordarialean taxa.

Molecular epidemiology of clinical filamentous fungi in Qatar beyond Aspergillus and Fusarium with notes on the rare species

Due to an increasing number of patients at risk (i.e., those with a highly compromised immune system and/or receiving aggressive chemotherapy treatment), invasive fungal infections (IFI) are increasingly being reported and associated with high mortality rates. Aspergillus spp., particularly A. fumigatus, is the major cause of IFI caused by filamentous fungi around the world followed by Fusarium spp., however, other fungi are emerging as human pathogens. The aim of this study was to explore the epidemiology and prevalence of the non-Aspergillus and non-Fusarium filamentous fungi in human clinical samples over an 11-year period in Qatar using molecular techniques. We recovered 53 filamentous fungal isolates from patients with various clinical conditions. Most patients were males (75.5%), 9.4% were immunocompromised, 20.7% had IFI, and 11.3% died within 30 days of diagnosis. The fungal isolates were recovered from a variety of clinical samples, including the nasal cavity, wounds, respiratory samples, body fluids, eye, ear, tissue, abscess, and blood specimens. Among the fungi isolated, 49% were dematiaceous fungi, followed by Mucorales (30%), with the latter group Mucorales being the major cause of IFI (5/11, 45.5%). The current study highlights the epidemiology and spectrum of filamentous fungal genera, other than Aspergillus and Fusarium, recovered from human clinical samples in Qatar, excluding superficial infections, which can aid in the surveillance of uncommon and emerging mycoses.

Da Vinci's yeast: Blastobotrys davincii f.a., sp. nov

A new species of the yeast genus Blastobotrys was discovered during a worldwide survey of culturable xerophilic fungi in house dust. Several culture-dependent and independent studies from around the world detected the same species from a wide range of substrates including indoor air, cave wall paintings, bats, mummies, and the iconic self-portrait of Leonardo da Vinci from ca 1512. However, none of these studies identified their strains, clones, or OTUs as Blastobotrys. We introduce the new species as Blastobotrys davincii f.a., sp. nov. (holotype CBS H-24879) and delineate it from other species using morphological, phylogenetic, and physiological characters. The new species of asexually (anamorphic) budding yeast is classified in Trichomonascaceae and forms a clade along with its associated sexual state genus Trichomonascus. Despite the decade-old requirement to use a single generic name for fungi, both names are still used. Selection of the preferred name awaits a formal nomenclatural proposal. We present arguments for adopting Blastobotrys over Trichomonascus and introduce four new combinations as Blastobotrys allociferrii (≡ Candida allociferrii), B. fungorum (≡ Sporothrix fungorum), B. mucifer (≡ Candida mucifera), and Blastobotrys vanleenenianus (≡ Trichomonascus vanleenenianus). We provide a nomenclatural review and an accepted species list for the 37 accepted species in the Blastobotrys/Trichomonascus clade. Finally, we discuss the identity of the DNA clones detected on the da Vinci portrait, and the importance of using appropriate media to isolate xerophilic or halophilic fungi.

Taxonomy of Botryotrichum luteum sp. nov. based on Morphology and Phylogeny Isolated from Soil in Korea

In this study, a fungal strain KNUF-22-025 belonging to the genus Botryotrichum was isolated from the soil in Korea. The cultural and morphological characteristics of this strain differed from those of closely related species. On malt extract agar, strain KNUF-22-025 showed slower growth than most of the related species, except B. domesticum. The conidia size (9.6-21.1 × 9.9-18.4 µm) of strain KNUF-22-025 was larger than those of B. piluliferum, B. domesticum, and B. peruvianum but smaller than those of B. atrogriseum and B. iranicum. Conidiophores in strain KNUF-22-025 (137 µm) were longer than those in other closely related species but shorter than those in B. atrogriseum. Multi-locus analysis of molecular markers, such as ITS, 28S ribosomal DNA, RBP2, and TUB2 revealed that strain KNUF-22-025 was distinct from other Botryotrichum species. Thus, this strain is proposed as a novel species based on morphological characteristics along with molecular phylogeny and named Botryotrichum luteum sp. nov.

Key insights into secondary metabolites from various Chaetomium species

Endophytic fungi have proved to be a major source of secondary metabolites, wherein the genus Chaetomium has emerged as a source of multifarious bioactive natural compounds belonging to diverse classes such as chaetoglobosins, epipolythiodioxopiperazines, azaphilones, xanthones, anthraquinone, chromones, depsidones, terpenoids, and steroids. The objective of this review is to encapsulate recent findings on various Chaetomium strains, such as C. globosum, C. cupreum, C. elatum, C. subspirale, C. olivaceum, C. indicum, and C. nigricolor known for production of beneficial secondary metabolites, with an insight into their origin and function. A thorough literature survey was conducted for obtaining Chaetomium-derived secondary metabolites, with a scope of future application into drug development efforts. More than 100 secondary metabolites, with various beneficial properties such as antitumor, cytotoxic, antimalarial, and enzyme inhibitory activities, were enlisted. We believe this review will enhance the understanding of beneficial effects conferred by various Chaetomium-derived secondary metabolites and emphasize their potential in serving novel drug development efforts. KEY POINTS: • Identified Chaetomium-derived metabolites with potential for drug development. • More than 100 beneficial metabolites are enlisted. • Benefits include anti-cancerous, antimalarial, and anti-enzymatic properties.

A Variety of Fungal Species on the Green Frogs' Skin (Pelophylax esculentus complex) in South Banat

In the last several decades, amphibian populations have been declining worldwide. Many factors have been linked to global amphibian decline, including habitat destruction, pollution, introduced species, global environmental changes, and emerging infectious diseases. Recent studies of amphibian skin infections were mainly focused on the presence of chytridiomycosis, neglecting other members of the frogs' skin communities. The diversity pattern of fungal dwellers on the skin of green frogs (Pelophylax esculentus complex) was investigated. A total of 100 adults were sampled from three localities in South Banat (northern Serbia) over three consecutive years and detected fungal dwellers were identified using light microscopy and ITS and BenA gene sequencing. Structures belonging to fungi and fungus-like organisms including a variety of spores and different mycelia types were documented in the biofilm formed on amphibian skin, and are classified into 10 groups. In total, 42 fungal isolates were identified to species, section, or genus level. The difference in mycobiota composition between sampling points (localities and green frog taxa) was documented. The highest number of fungal structures and isolates was recorded on the hybrid taxon P. esculentus and locality Stevanove ravnice. Parental species showed a markedly lower diversity than the hybrid taxon and were more similar in diversity patterns and were placed in the same homogenous group. The locality Stevanove ravnice exhibited more pronounced differences in diversity pattern than the other two localities and was placed in a distinct and separate homogenous group. Among the fungal isolates, the highest isolation frequency was documented for Alternaria alternata, Aspergillus sp. sect. Nigri, Epicoccum nigrum, Fusarium proliferatum, and Trichoderma atroviride. Among the documented species, dematiaceous fungi, causative agents of chromomycosis in amphibians, were also recorded in this research with high isolation frequency. Also, some rare fungal species such as Quambalaria cyanescens and Pseudoteniolina globosa are documented for the first time in this research as microbial inhabitants of amphibian skin.

Trichocladium solani sp. nov.—A New Pathogen on Potato Tubers Causing Yellow Rot

A new species, Trichocladium solani, was isolated from potato (Solanum tuberosum L.) tubers from Russia. The species has no observed teleomorph and is characterized morphologically by non-specific Acremonium-like conidia on single phialides and chains of swollen chlamydospores. Phylogenetic analysis placed the new species in a monophyletic clade inside the Trichocladium lineage with a high level of support from a multi-locus analysis of three gene regions: ITS, tub2, and rpb2. ITS is found to be insufficient for species delimitation and is not recommended for identification purposes in screening studies. T. solani is pathogenic to potato tubers and causes lesions that look similar to symptoms of Fusarium dry rot infection but with yellowish or greenish tint in the necrotized area. The disease has been named “yellow rot of potato tubers”.

Pigment produced from Arcopilus aureus isolated from grapevines: Promising natural yellow colorants for the food industry

Interest in the use of natural non-toxic pigments by the food industry has grown. Some filamentous fungi are producers of natural pigments that are more stable at temperature and pH than other pigments also classified as natural, such as those produced by plants. Production potential of natural pigments by endophytic fungi from grapevines was evaluated. Arcopilus aureus was selected as a potential source for a yellow pigment, which was characterized and tested for stability to variations in temperature and pH. Components, cochlioquinol II and riboflavin, were detected, which has not previously been reported in A. aureus. The pigment was stable and showed increased absorption at lower / acidic pH. These results provide information on the potential of this fungus and a yellow pigment for the first time, which can be used for further development and industrial application.

Acrophialophora jodhpurensis: an endophytic plant growth promoting fungus with biocontrol effect against Alternaria alternata

In this study, efficiency of the endophytic fungal isolate Msh5 was evaluated on promoting tomato plant growth and controlling Alternaria alternata, the causal agent of early blight in tomatoes. Morphological and molecular (ITS and tub2 sequences) analyses revealed that the fungal isolate, Msh5, was Acrophialophora jodhpurensis (Chaetomium jodhpurense Lodha). This beneficial fungus was capable of producing indole-3-acetic acid (IAA), urease, siderophore, extracellular enzymes, and solubilized phosphate. Under laboratory conditions, the Msh5 isolate of A. jodhpurensis inhibited A. alternata growth in dual culture, volatile and non-volatile metabolites assays. The supernatant of this endophytic fungus was capable of reducing spore germination and altering the hyphal structure of A. alternata and the spores produced germ tubes showed vacuolization and abnormal structure compared to the control. Also, the effect of A. jodhpurensis on plant growth parameters (such as shoot and root weight and length) and suppressing A. alternata was investigated in vivo via seed inoculation with spores of A. jodhpurensis using 1% sugar, 0.5% carboxymethyl cellulose (CMC) or 0.5% molasses solution as stickers. Colonization of tomato roots by the endophytic fungus resulted in significant increasing plant growth parameters and reduction in the progress of the diseases caused by A. alternata compared to the controls. Among the different coating materials used as stickers, sugar was found to be the most effective for enhancing plant growth parameters and decreasing the disease progress. Therefore, A. jodhpurensis isolate Msh5 can be suggested as a potential biofertilizer and biocontrol agent for protecting tomato plants against A. alternata.

Corrections to recent changes in the taxonomy of the Sordariales

The classification of taxa belonging to the Sordariales has been problematic over the years. With the beginning of the DNA era, ascospore morphology, which was the main criterium for the delimitation of taxa in the Sordariales, was demonstrated to not be useful for inferring taxonomic relationships especially at the genus level. In the past decades, the combination of both morphological and molecular data allowed the reclassification of these taxa. Recently, a study of some often overlooked Diaporthomycetidae and Sordariomycetidae included a new taxonomic classification for members of the Sordariales, many of which were based on nomenclatural errors or which lacked sufficient data to support their hypotheses. The authors did not contribute any new DNA sequences, but instead relied on datasets generated by previous authors in their published phylogenetic studies. Surprisingly, different results were obtained contradicting these previous studies and, in an act of taxonomic vandalism, five new families were introduced without performing further molecular analyses to verify the incongruencies with these previous studies. Three of these new families, which we consider doubtful, are Bombardiaceae, Lasiosphaeridaceae and Zygospermellaceae. The family Strattoniaceae is here considered superfluous since it was introduced to accommodate only a single genus and delimited based on a species that is not the type species of Strattonia. The Neoschizotheciaceae was erected based on the new genus Neoschizothecium, which was introduced to accommodate members of Schizothecium since Huang et al. (2021) considered Schizothecium as a synonym of Podospora after misinterpreting their type species as the same. However, Schizothecium and Podospora have been two independent genera based on two different type species for half a century, making Neoschizothecium and Neoschizotheciaceae superfluous. Moreover, they proposed 32 new combinations, 16 of which are now superfluous or doubtful. Most of these taxonomic errors could have been avoided if a proper literature review had been performed. Two examples are the new superfluous combinations of Triangularia tarvisina and Cladorrhinum olerum, because the former is considered conspecific with Triangularia setosa, and the latter conspecific with Cladorrhinum foecundissimum, the anamorph of Arnium olerum. The focus of the current review is to provide a scientifically responsible alternative to the erroneous novelties proposed at the family, genus and species level in the recent classification of Sordariales.

Morpho-molecular characterisation of Arecophila, with A. australis and A. clypeata sp. nov. and A. miscanthi comb. nov

Three arecophila-like fungal samples were collected on dead culms of gramineous plants in China. Morphological studies of our new collections and the herbarium specimen of Arecophila gulubiicola (generic type) were conducted and the morphological affinity of our new collections with Arecophila was confirmed. Maximum likelihood and Bayesian analyses using combined ITS, LSU, rpb2 and β-tubulin data from our collections revealed the phylogeny of Cainiaceae. The monospecific genus Alishanica (type species Al. miscanthi), which had been accepted in Cainiaceae, is revisited and synonymised under Arecophila. Based on morphology and phylogeny, Arecophila australis sp. nov. and A. clypeata sp. nov. are introduced as new species, while A. miscanthi is a new record for China. All the new collections are illustrated and described.

Diversity of biologically active secondary metabolites in the ascomycete order Sordariales

Ascomycetes belonging to the order Sordariales are a well-known reservoir of secondary metabolites with potential beneficial applications. Species of the Sordariales are ubiquitous, and they are commonly found in soils and in lignicolous, herbicolous, and coprophilous habitats. Some of their species have been used as model organisms in modern fungal biology or were found to be prolific producers of potentially useful secondary metabolites. However, the majority of sordarialean species are poorly studied. Traditionally, the classification of the Sordariales has been mainly based on morphology of the ascomata, ascospores, and asexual states, characters that have been demonstrated to be homoplastic by modern taxonomic studies based on multi-locus phylogeny. Herein, we summarize for the first time relevant information about the available knowledge on the secondary metabolites and the biological activities exerted by representatives of this fungal order, as well as a current outlook of the potential opportunities that the recent advances in omic tools could bring for the discovery of secondary metabolites in this order.

A Culture-Based Study of Micromycetes Isolated from the Urban Nests of Grey Heron (Ardea cinerea) in SW Poland

Simple Summary

Fungi inhabiting bird nests may pose a serious threat to living organisms. Therefore, the main goal of the study was to identify cultivable fungi in the nest of grey heron (Ardea cinerea) located near the city centre of Wrocław (Poland). Overall, 10 different fungal species were obtained which were both cosmopolitan and potentially hazardous to humans, homoiothermous animals and plants. The greatest number of fungal species was obtained from the nest fragments with visible fungal growth, and the least from western conifer seed bugs (Leptoglossus occidentalis) inhabiting the nests. The damp chamber allowed isolation of Aspergillus fumigatus, Penicillium coprophilum, and P. griseofulvum as directly related to the occurrence of visible fungal growth on plant fragments of grey heron nests.

Abstract

There are many positive relationships between micromycetes and birds: They can spread fungal spores, and fungi facilitate cavity woodpecker excavation by preparing and modifying excavation sites. In turn, bird nests are mainly a source of potentially zoopathogenic fungi. The Wrocław city centre hosts the biggest grey heron breeding colony in Poland with at least 240 breeding birds pairs. To assess the possible public health risks associated with bird nests, the goal of the present study was to identify cultivable fungi present in the nests of grey herons (Ardea cinerea) in Wrocław. Additionally, attempts were made to determine whether the obtained species of fungi may pose a potential threat to animal health. Fungi were cultured at 23 and 37 ± 0.5 °C, and identified based on phenotypic and genotypic traits. Moreover, during routine inspection, visible fungal growth in some of the nests was found. Overall, 10 different fungal species were obtained in the study (Alternaria alternata, Aspergillus fumigatus, Botryotrichum piluliferum, Cladosporium cladosporioides, Epicoccum layuense, Mucor circinelloides, M.hiemalis, Penicillium atramentosum, P.coprophilum, and P.griseofulvum). They are both cosmopolitan species and a source of potential threat to humans, homoiothermous animals and plants. The greatest number of fungal species was obtained from the nest fragments with visible fungal growth incubated at 23 °C, and the least from western conifer seed bugs (Leptoglossus occidentalis) inhabiting the nests. The species such as A. fumigatus, P. coprophilum, and P.griseofulvum can be directly related to the occurrence of visible fungal growth on plant fragments of grey heron’s nests.

Synergistic effects of crop residue and microbial inoculant on soil properties and soil disease resistance in a Chinese Mollisol

The soil-borne disease caused by Fusarium graminearum seriously affects the corn quality. Straw can greatly improve soil quality, but the effect is limited by its nature and environmental factors. This study explored the impact of straw-JF-1(biocontrol bacteria) combination on soil environment and soil disease resistance. The results showed that the combined treatment increased the proportion of soil large and small macro-aggregates by 22.50 and 3.84%, with soil organic carbon (SOC) content by 16.18 and 16.95%, respectively. Compared to treatment with returning straw to the field alone, the straw-JF-1 combination increased the soil content of humic acid, fulvic acid, and humin by 14.06, 5.50, and 4.37%, respectively. Moreover, A metagenomics showed that returning straw to the field alone increased the abundance of disease-causing fungi (Fusarium and Plectosphaerella), however, the straw-JF-1 combination significantly suppressed this phenomenon as well as improved the abundance of probiotic microorganisms such as Sphingomonas, Mortierella, Bacillus, and Pseudomonas. Functional analysis indicated that the combination of straw and JF-1 improved some bacterial functions, including inorganic ion transport and metabolism, post-translational modification/protein turnover/chaperones and function unknown, fungal functions associated with plant and animal pathogens were effectively inhibited. Pot experiments showed that the straw-JF-1 combination effectively inhibited the Fusarium graminearum induced damage to maize seedlings. Therefore, the combination of straw and JF-1 could be a practical method for soil management.

In vitro activity of eight antifungal drugs against Chaetomiaceae

The incidence of infections caused by uncommon Chaetomiaceae (Chaetomium and related species) in humans has increased in the recent years. The in vitro activity of eight antifungal drugs (amphotericin B, five azoles, two echinocandins) against 42 morphologically identified Chaetomium strains was determined according to the Clinical and Laboratory Standards Institute (CLSI) guideline. The strains were subsequently identified based on sequences of the internal transcribed spacer 1 and 2 including the intervening 5.8S nrDNA region (ITS) and the partial β tubulin gene (tub2). Chaetomium globosum (n = 24), was the most frequently isolated species, followed by Amesia atrobrunnea (syn. Chaetomium atrobrunnea, n = 6), Dichotomopilus dolichotrichus (syn. Chaetomium dolichotrichum, n = 2) and Acrophialophora jodhpurensis, Chaetomium coarctatum, C. elatum, C. gracile, C. subaffine, C. tarraconense, C. unguicola, Dichotomopilus sp., Dichotomopilus variostiolatus, Ovatospora brasiliensis (all represented by a single strain). The geometric means of the minimum inhibitory concentrations/minimum effective concentrations (MICs/MECs) of the antifungals across all strains were (in increasing order): micafungin 0.12 µg/ml, itraconazole and posaconazole 0.21 µg/ml, amphotericin B 0.25 µg/ml, voriconazole 0.45 µg/ml, isavuconazole 0.54 µg/ml, caspofungin 2.57 µg/ml, and fluconazole 45.25 µg/ml. Micafungin had the lowest geometric mean followed by amphotericin B which had the largest range against tested isolates. All examined C. globosum strains had similar antifungal susceptibility patterns. Fluconazole and caspofungin could not be considered as an option for treatment of infections caused by Chaetomium and chaetomium-like species.

LAY SUMMARY

Infections caused by uncommon fungi such as Chaetomium have increased in the recent years. Chaetomium globosum has been reported from onychomycosis and phaeohyphomycosis. This species often induces superficial infections in immunocompetent patients. The taxonomy of Chaetomium spp. has changed dramatically in the last years. Antifungal treatment is a crucial step for managing these kinds of infections. Therefore, the in vitro activity of eight antifungal drugs against Chaetomium strains was determined and β-tubulin (tub2) sequencing was applied to identify the strains. Chaetomium globosum was the most frequent species in our dataset. Based on the results of susceptibility testing, micafungin had the lowest geometric mean followed by amphotericin B. Fluconazole and caspofungin cannot be considered a proper treatment option for infections caused by Chaetomium and chaetomium-like species.

Insights into the Lignocellulose-Degrading Enzyme System of Humicola grisea var. thermoidea Based on Genome and Transcriptome Analysis

Humicola grisea var. thermoidea is a thermophilic ascomycete and important enzyme producer that has an efficient enzymatic system with a broad spectrum of thermostable carbohydrate-active (CAZy) enzymes. These enzymes can be employed in lignocellulose biomass deconstruction and other industrial applications. In this work, the genome of H. grisea var. thermoidea was sequenced. The acquired sequence reads were assembled into a total length of 28.75 Mbp. Genome features correlate with what was expected for thermophilic Sordariomycetes. The transcriptomic data showed that sugarcane bagasse significantly upregulated genes related to primary metabolism and polysaccharide deconstruction, especially hydrolases, at both pH 5 and pH 8. However, a number of exclusive and shared genes between the pH values were found, especially at pH 8. H. grisea expresses an average of 211 CAZy enzymes (CAZymes), which are capable of acting in different substrates. The top upregulated genes at both pH values represent CAZyme-encoding genes from different classes, including acetylxylan esterase, endo-1,4-β-mannosidase, exoglucanase, and endoglucanase genes. For the first time, the arsenal that the thermophilic fungus H. grisea var. thermoidea possesses to degrade the lignocellulosic biomass is shown. Carbon source and pH are of pivotal importance in regulating gene expression in this organism, and alkaline pH is a key regulatory factor for sugarcane bagasse hydrolysis. This work paves the way for the genetic manipulation and robust biotechnological applications of this fungus.

IMPORTANCE Most studies regarding the use of fungi as enzyme producers for biomass deconstruction have focused on mesophile species, whereas the potential of thermophiles has been evaluated less. This study revealed, through genome and transcriptome analyses, the genetic repertoire of the biotechnological relevant thermophile fungus Humicola grisea. Comparative genomics helped us to further understand the biology and biotechnological potential of H. grisea. The results demonstrate that this fungus possesses an arsenal of carbohydrate-active (CAZy) enzymes to degrade the lignocellulosic biomass. Indeed, it expresses more than 200 genes encoding CAZy enzymes when cultivated in sugarcane bagasse. Carbon source and pH are key factors for regulating the gene expression in this organism. This work shows, for the first time, the great potential of H. grisea as an enzyme producer and a gene donor for biotechnological applications and provides the base for the genetic manipulation and robust biotechnological applications of this fungus.

A Putative C2H2 Transcription Factor CgTF6, Controlled by CgTF1, Negatively Regulates Chaetoglobosin A Biosynthesis in Chaetomium globosum

Gα signaling pathway as well as the global regulator LaeA were demonstrated to positively regulate the biosynthesis of chaetoglobosin A (ChA), a promising biotic pesticide produced by Chaetomium globosum. Recently, the regulatory function of Zn2Cys6 binuclear finger transcription factor CgcheR that lies within the ChA biosynthesis gene cluster has been confirmed. However, CgcheR was not merely a pathway specific regulator. In this study, we showed that the homologs gene of CgcheR (designated as Cgtf1) regulate ChA biosynthesis and sporulation in C. globosum NK102. More importantly, RNA-seq profiling demonstrated that 1,388 genes were significant differentially expressed as Cgtf1 deleted. Among them, a putative C2H2 transcription factor, named Cgtf6, showed the highest gene expression variation in zinc-binding proteins encoding genes as Cgtf1 deleted. qRT-PCR analysis confirmed that expression of Cgtf6 was significantly reduced in CgTF1 null mutants. Whereas, deletion of Cgtf6 resulted in the transcriptional activation and consequent increase in the expression of ChA biosynthesis gene cluster and ChA production in C. globosum. These data suggested that CgTF6 probably acted as an end product feedback effector, and interacted with CgTF1 to maintain a tolerable concentration of ChA for cell survival.

Occupational exposure to fungi on recyclable paper pots and growing media and associated health effects - A review of the literature

Different types of pots and growing and casing media, including biodegradable materials, are used for plant and mushroom production. The fungus Peziza ostracoderma has gained attention for its visible growth on growing media for plants and casing media for mushrooms. Through a review of the literature we aim to evaluate whether exposure to fungi from recyclable pots and different growing and casing media occurs and causes occupational health effects. Based on the published papers, specific fungal species were not related to a specific medium. Thus P. ostracoderma has been found on paper pots, peat, sterilized soil, vermiculite, and rockwool with plants, and on peat, pumice, and paper casing for mushrooms. It has been found in high concentrations in the air in mushroom farms. Also Acremonium spp., Aspergillus niger, A. fumigatus, Athelia turficola, Aureobasidium pullulans, Chaetomium globosum, Chrysonilia sitophila, Cladosporium spp., Cryptostroma corticale, Lecanicillium aphanocladii, Sporothrix schenckii, Stachybotrys chartarum, and Trichoderma spp. have been found on different types of growing or casing media. Most of the fungi have also been found in the air in greenhouses, but the knowledge about airborne fungal species in mushroom farms is very limited. Eight publications describe cases of health effects associated directly with exposure to fungi from pots or growing or casing media. These include cases of hypersensitivity pneumonitis caused by exposure to: A. fumigatus, A. niger, Au. pullulans, Cr. corticale, P. ostracoderma, and a mixture of fungi growing on different media. Different approaches have been used to avoid growth of saprophytes including: chemical fungicides, the formulation of biodegradable pots and growing media and types of peat. To increase the sustainability of growing media different types of media are tested for their use and with the present study we highlight the importance of also considering the occupational health of the growers who may be exposed to fungi from the media and pots.

Chaetomium and Chaetomium-like Species from European Indoor Environments Include Dichotomopilus finlandicus sp. nov

The genus Chaetomium is a frequently occurring fungal taxon world-wide. Chaetomium and Chaetomium-like species occur in indoor environments, where they can degrade cellulose-based building materials, thereby causing structural damage. Furthermore, several species of this genus may also cause adverse effects on human health. The aims of this research were to identify Chaetomium and Chaetomium-like strains isolated from indoor environments in Hungary and Finland, two geographically distant regions of Europe with drier and wetter continental climates, respectively, and to study their morphological and physiological properties, as well as their extracellular enzyme activities, thereby comparing the Chaetomium and Chaetomium-like species isolated from these two different regions of Europe and their properties. Chaetomium and Chaetomium-like strains were isolated from flats and offices in Hungary, as well as from schools, flats, and offices in Finland. Fragments of the translation elongation factor 1α (tef1α), the second largest subunit of RNA polymerase II (rpb2) and β-tubulin (tub2) genes, as well as the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster were sequenced, and phylogenetic analysis of the sequences performed. Morphological examinations were performed by stereomicroscopy and scanning electron microscopy. Thirty-one Chaetomium sp. strains (15 from Hungary and 16 from Finland) were examined during the study. The most abundant species was Ch. globosum in both countries. In Hungary, 13 strains were identified as Ch. globosum, 1 as Ch. cochliodes, and 1 as Ch. interruptum. In Finland, 10 strains were Ch. globosum, 2 strains were Ch. cochliodes, 2 were Ch. rectangulare, and 2 isolates (SZMC 26527, SZMC 26529) proved to be representatives of a yet undescribed phylogenetic species from the closely related genus Dichotomopilus, which we formally describe here as the new species Dichotomopilus finlandicus. Growth of the isolates was examined at different temperatures (4, 15, 20, 25, 30, 37, 35, 40, and 45 °C), while their extracellular enzyme production was determined spectrophotometrically.

Effects of chloropicrin fumigation combined with biochar on soil bacterial and fungal communities and Fusarium oxysporum

Chloropicrin (CP) can cause long-term damage to beneficial microbes which reduces soil health. Biochar (BC) can mitigate against the effects of CP by reducing the time for beneficial microbes to recover after CP fumigation. In this study, we used Real-Time Quantitative PCR to determine the effects of different rates of BC added to CP-fumigated soil on the speed of recovery of bacteria and fungi population and on changes to gene copy number of the target pathogen Fusarium oxysporum. And then we compared the structure and composition of the beneficial microbial community in the different treatments soil by using High throughput Illumina sequencing. As the results shown, adding 1 or 3% BC after CP fumigation accelerated the recovery of bacterial and fungal populations without increasing F. oxysporum abundance. BC also promoted the recovery of beneficial bacteria Rokubacteria and Latescibacteria damaged by CP. And these two bacteria may be related to the immunity of soil to F. oxysporum. In CP-fumigated soil, BC improved the disease resistance of the soil by increasing beneficial microbes, such as Steroidobacter, Sphingomonas, Purpureocillium and Mortierella. This combination of CP and BC is a new concept that could encourages the development of a healthy and sustainable soil ecosystems while controlling plant pathogens.

Genome and Secretome Analysis of Staphylotrichum longicolleum DSM105789 Cultured on Agro-Residual and Chitinous Biomass

Staphylotrichum longicolleum FW57 (DSM105789) is a prolific chitinolytic fungus isolated from wood, with a chitinase activity of 0.11 ± 0.01 U/mg. We selected this strain for genome sequencing and annotation, and compiled its growth characteristics on four different chitinous substrates as well as two agro-industrial waste products. We found that the enzymatic mixture secreted by FW57 was not only able to digest pre-treated sugarcane bagasse, but also untreated sugarcane bagasse and maize leaves. The efficiency was comparable to a commercial enzymatic cocktail, highlighting the potential of the S. longicolleum enzyme mixture as an alternative pretreatment method. To further characterize the enzymes, which efficiently digested polymers such as cellulose, hemicellulose, pectin, starch, and lignin, we performed in-depth mass spectrometry-based secretome analysis using tryptic peptides from in-gel and in-solution digestions. Depending on the growth conditions, we were able to detect from 442 to 1092 proteins, which were annotated to identify from 134 to 224 putative carbohydrate-active enzymes (CAZymes) in five different families: glycoside hydrolases, auxiliary activities, carbohydrate esterases, polysaccharide lyases, glycosyl transferases, and proteins containing a carbohydrate-binding module, as well as combinations thereof. The FW57 enzyme mixture could be used to replace commercial enzyme cocktails for the digestion of agro-residual substrates.

Recent developments in less known and multi-resistant fungal opportunists

Fungal infections have increased in recent years due to host factors, such as oncohaematological and transplant-related disorders, immunosuppressive therapy, and AIDS. Additionally, molecular and proteomic facilities have become available to identify previously unrecognizable opportunists. For these reasons, reports on less-known and recalcitrant mycoses, such as those caused by black fungi, hyaline filamentous fungi, coelomycetes, Mucorales, and non-Candida yeasts have emerged. In this review, novel taxonomy in these groups, which often are multi-resistant to one or several classes of antifungals, is discussed. Clinical presentations, diagnosis and current treatment of some major groups are summarised.

First report of Arcopilus aureus causing leaf black spot disease of Pseudostellaria heterophylla in China

Pseudostellaria heterophylla (family Caryophyllaceae) is a perennial herbaceous plant. Its tuberous roots are highly valued in traditional Chinese medicine. It is mainly cultivated in a geo-authentic production zone located in the Guizhou, Anhui, Shandong, and Fujian provinces of China (Zhao et al. 2016). The herb is widely used for treating lung diseases and as a spleen tonic (Pang et al. 2011). A severe leaf black spot disease was observed on P. heterophylla in China, from 2018 to 2020. Plants displayed water-soaking symptoms in the early stage of infection, then the watery areas turned brown-red and a black mold appeared on the lesions. At a later stage, the leaf spots showed concentric rings surrounded by a yellow halo, and the initial infection site became dry and necrotic (Supplementary Figure S1). Nine infected plants were collected from three cultivation fields in Shibing County (N 27°4'21", E 108°8'0"), Guizhou province, on April 13th, 2019. The fungus was consistently isolated from symptomatic leaves on potato dextrose agar (PDA) medium according to the method described by Larran et al (2002). A total of 22 isolates were obtained, including 7 isolates of Arcopilus and 15 isolates of Trichoderma. The growth rates of isolate MJ2-2b on PDA and oatmeal agar (OA) medium were 3 to 5 mm/day at 25 °C (Supplementary Figure S2A and S2B). Mycelium of isolate MJ2-2b was dense, yellowish-brown on PDA, while it was sparse, bright-red on OA. Also, the mycelium secreted brownish-red pigment on both PDA and OA. Ascomata when mature were water drop and limoniform. Lateral hairs were brown, erect or flexuous, tapering towards the tips. Ascospores when mature were greyish-white to grey, limoniform, or fusiform to pyriform (Supplementary Figure S2C and S2D). Further, the beta-tubulin gene (Tub2) of the fungus was amplified by using primer pairs T1 and TUB4Rd as described by Wang et al (2016) and subjected to sequencing. NCBI nucleotide BLAST results showed that sequences from seven isolates had a 99.86% identity with A. aureus (strain ChL-C, GenBank accession No. MG889987.1) (Supplementary Figure S2F). Molecular phylogenetic analysis by maximum likelihood method using MEGA 7 confirmed that the fungal isolate clustered with A. aureus. Hence, the causal agent was identified as A. aureus based on morphological and molecular characteristics. The sequence was deposited in GenBank (accession No. MW531453). Pathogenicity tests were conducted on 15-day old tissue-cultured seedlings according to Ghanbary et al (2018) (Supplementary Figure S3). Leaves of 16 seedlings were inoculated with 1×1 mm 5-day-old PDA-grown mycelial plugsof the fungal isolate. The experiment was repeated 3 times. After 10 days, the inoculated leaves showed the same symptoms observed on plants in the field. The associated fungal pathogen was consistently re-isolated from the inoculated seedlings and identified by Tub2 gene sequencing. At present, there are no reports of A. aureus causing disease of plants. To the best of our knowledge, this is the first report of leaf black spot disease on P. heterophylla caused by A. aureus in China.

Mycobiota Associated with the Vascular Wilt of Poplar

In 2017, a 560-ha area of hybrid poplar plantation in northern Poland showed symptoms of tree decline. The leaves appeared smaller, yellow-brown, and were shed prematurely. Twigs and smaller branches died without distinct cankers. Trunks decayed from the base. The phloem and xylem showed brown necrosis. Ten percent of the trees died 1–2 months after the first appearance of the symptoms. None of these symptoms were typical for known poplar diseases. The trees’ mycobiota were analysed using Illumina sequencing. A total of 69 467 and 70 218 operational taxonomic units (OTUs) were obtained from the soil and wood. Blastocladiomycota and Chytridiomycota occurred only in the soil, with very low frequencies (0.005% and 0.008%). Two taxa of Glomeromycota, with frequencies of 0.001%, occurred in the wood. In the soil and wood, the frequencies of Zygomycota were 3.631% and 0.006%, the frequencies of Ascomycota were 45.299% and 68.697%, and the frequencies of Basidiomycota were 4.119% and 2.076%. At least 400 taxa of fungi were present. The identifiable Zygomycota, Ascomycota, and Basidiomycota were represented by at least 18, 263 and 81 taxa, respectively. Many fungi were common to the soil and wood, but 160 taxa occurred only in soil and 73 occurred only in wood. The root pathogens included species of Oomycota. The vascular and parenchymal pathogens included species of Ascomycota and of Basidiomycota. The initial endophytic character of the fungi is emphasized. Soil, and possibly planting material, may be the sources of the pathogen inoculum, and climate warming is likely to be a predisposing factor. A water deficit may increase the trees’ susceptibility. The epidemiology of poplar vascular wilt reminds grapevine trunk diseases (GTD), including esca, black foot disease and Petri disease.

Foliar Endophytic Fungi Inhabiting an Annual Grass Along an Aridity Gradient

Mutualistic fungi are known to increase plant tolerance to abiotic and biotic stress. Therefore, it is expected that along aridity gradients the diversity and composition of symbiotic fungal community will be associated with climate. We examined the diversity of foliar endophytic fungi, inhabiting an annual grass, growing in three different climates (arid, Mediterranean, and wet Mediterranean) along the Israeli aridity gradient. Among the identified endophyte taxa, some were unique to each site, some were common to the two sites located in the extremes of the gradient, but none was common to all sites. Although most fungal endophyte taxa identified were not related to stress adaptation, we detected two that are considered to benefit plants by mitigating stress: Cladosporium and Trichoderma. Cladosporium is highly osmotolerant, frequently found in saline environments. Trichoderma is a biocontrol agent, frequently found in mesic environments. These findings support the hypothesis that species composition of foliar endophytic fungi is associated with stress adaptation of plants.

Staphylotrichum sinense sp. nov., a new hyphomycete (Chaetomiaceae) from China

Staphylotrichum sinense, a new hyphomycete classified in the Chaetomiaceae (Ascomycota), was isolated from soil in Jianshui county, Yunnan Province. It is characterized by globose and ochreous conidia born laterally on aerial hyphae, and micronematous, unbranched and 0-1-septate conidiophores, sometimes reduced to conidiogenous cells. Morphologically, Staphylotrichum sinense is similar to Staphylotrichum boninense, but it can be distinguished by lacking of macronematous conidiophores and having larger conidia. Phylogenetically Staphylotrichum sinense formed a single clade within Staphylotrichum species, and is closely related to Staphylotrichum boninense and Staphylotrichum brevistipitatum.

Delimitation and phylogeny of Dictyochaeta, and introduction of Achrochaeta and Tubulicolla, genera nova

Dictyochaeta (Chaetosphaeriaceae) is a phialidic dematiaceous hyphomycete with teleomorphs classified in Chaetosphaeria. It is associated with significant variability of asexual morphological traits, which led to its broad delimitation. In the present study, six loci: nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode), nuc 18S rDNA (18S), nuc 28S rDNA (28S), DNA-directed RNA polymerase II second largest subunit gene (RPB2), translation elongation factor 1-α (TEF1-α), and β-tubulin (TUB2), along with comparative morphological and cultivation studies, are used to reevaluate the concept of Dictyochaeta and establish species boundaries. Based on revised species, morphological characteristics of conidia (shape, septation, absence or presence of setulae), collarettes (shape), and setae (presence or absence) and an extension of the conidiogenous cell proved to be important at the generic level. The dual DNA barcoding using ITS and TEF1-α, together with TUB2, facilitated accurate identification of Dictyochaeta species. Thirteen species are accepted, of which seven are characterized in this study; an identification key is provided. It was revealed that D. fuegiana, the type species, is a complex of three distinct species including D. querna and the newly described D. stratosa. Besides, a new species, D. detriticola, and two new combinations, D. callimorpha and D. montana, are proposed. An epitype of D. montana is selected. Dictyochaeta includes saprobes on decaying wood, bark, woody fruits, and fallen leaves. Dictyochaeta is shown to be distantly related to the morphologically similar Codinaea, which is resolved as paraphyletic. Chaetosphaeria talbotii with a Dictyochaeta anamorph represents a novel lineage in the Chaetosphaeriaceae; it is segregated from Dictyochaeta, and a new genus Achrochaeta is proposed. Multigene phylogenetic analysis revealed that D. cylindrospora belongs to the Vermiculariopsiellales, and a new genus Tubulicolla is introduced.

Name Changes for Fungi of Medical Importance, 2018 to 2019

The current article summarizes recent changes in nomenclature for fungi of medical importance published in the years 2018 to 2019, including new species and revised names for existing ones. Many of the revised names have been widely adopted without further discussion. However, those that concern common pathogens of humans may take longer to achieve general usage, with new and current names reported together to engender increasing familiarity with the correct taxonomic classification.

A Pilot Study on Baseline Fungi and Moisture Indicator Fungi in Danish Homes

In many complaint cases regarding bad indoor environments, there is no evidence of visible fungal growth. To determine if the problems are fungi-related, dust sampling is the method of choice among building surveyors. However, there is a need to differentiate between species belonging to a normal, dry indoor environment and species belonging to a damp building envelope. The purposes of this pilot study were to examine which fungal species are present in problem-free Danish homes and to evaluate different detection and identification methods. Analyses showed that the fungal diversity outside was different from the diversity inside and that the composition of fungal species growing indoors was different compared to those found as spores, both indoors and outdoors. Common for most homes were Pseudopithomyceschartarum, Cladosporiumallicinum and Alternaria sect. Infectoriae together with Botrytis spp., Penicilliumdigitatum and Pen. glabrum. The results show that ITS sequencing of dust samples is adequate if supported by thorough building inspections and that food products play as large a role in the composition of the baseline spora as the outdoor air and surrounding vegetation. This pilot study provides a list of baseline fungal species found in Danish homes with a good indoor environment.

Identification and molecular characterization of Subramaniula asteroides causing human fungal keratitis: a case report

Background

Keratitis due to by filamentous fungi are not easy to diagnose thus causing a delay in correct therapy. There are many descriptions of keratitis due to Candida, Fusarium and Aspergillus genera. Subramaniula genus has only recently been reported to cause human infections and there are few descriptions of eye infections due to this filamentous fungus. Diagnosis of fungal keratitis is usually based on microscopic and cultural techniques of samples obtained by corneal swabbing or scraping. Considering the amount of time required to obtain culture results it is wise to use other diagnostic methods, such as molecular analyses. Therapeutic options against these fungi are limited by low tissue penetration in the eye due to ocular barriers. We describe the first case of S. asteroides human keratitis treated with isavuconazole.

Case presentation

We describe a rare case of fungal keratitis unresponsive to antimicrobial treatment in a 65-year-old male patient without a history of diabetes or immunological diseases. He reported that the onset of symptoms occurred during a long holiday in Cape Verde Island. Initial treatment with topical antibiotics associated to steroids were ineffective, allowing a slow clinical progression of disease to corneal perforation. On admission in our Hospital, slit-lamp examination of the left eye showed conjunctival congestion and hyperemia, a large inferior corneal ulceration with brown pigment, corneal edema, about 3 mm of hypopyon and irido-lenticular synechiae. The slow clinical progression of the disease to corneal perforation and the aspect of the ulcer were consistent with a mycotic etiology. Molecular methods used on fungal colonies isolated by Sabouraud’s dextrose agar cultures allowed the identification of Subramaniula asteroids from corneal scraping. Antimicrobial test showed a good susceptibility of this filamentous fungus to voriconazole and isavuconazole. Moreover, this fungal keratitis was successfully treated with isavuconazole, without side effects, observing a progressive clinical improvement.

Conclusions

Molecular methods may be useful for the identification of filamentous fungal keratitis on scraping samples thus shortening the time of diagnosis. Systemic therapy by isavuconazole could be useful to treat the filamentous fungal keratitis, reducing the possible adverse effects due to the use of voriconazole by systemic administration.

Essential Oils as Alternative Biocides for the Preservation of Waterlogged Archaeological Wood

Waterlogged archaeological wood is exposed to a high risk of biological degradation during the post-excavation phases of storage and restoration. For this reason, often biocides must be used to preserve wooden remains. In the present work three essential oils (cinnamon, wild thyme, and common thyme) were tested as possible alternative biocides to use in the preservation of waterlogged archaeological wood. The oils were first tested in vitro to establish the minimum inhibitory concentration (MIC) and to evaluate the biocidal activity on selected fungal strains. Then, the established MIC was applied on waterlogged archaeological wood samples and during an actual restoration treatment. The effectiveness of the oils was evaluated through cultural analyses, ATP quantification, and next-generation sequencing. The results showed that the oils caused a significant decrease in the vitality of fungal mycelia grown in vitro and of the microbiota present in treated wood and storage water. Furthermore, an influence on the composition of the bacterial communities of treated wood samples was observed. Although further tests are needed to evaluate interferences with the materials used during restoration procedures, essential oils could be considered as a possible alternative to the currently used biocide.

Characterization of cultural traits and fungicidal activity of strains belonging to the fungal genus Chaetomium

AIMS

Compare and characterize Chaetomium strains with special regard to their potentialities as biocontrol agents.

METHODS AND RESULTS

Twelve strains of the fungal genus Chaetomium from diverse ecological niches were identified as belonging to six different species. Large differences were observed between the strains with regard to temperature requirements for mycelial growth and pigmentation of culture filtrates. Culture filtrates and ethyl acetate extracts were assayed for fungicidal effects against important phytopathogens both on agar media and in multiwell plates. The samples from Chaetomium globosum were particularly active against Botrytis cinerea, Pyrenophora graminea and Bipolaris sorokiniana, while those from C. cochliodes and C. aureum were inhibitory towards Phytophthora infestans, and P. infestans and Fusarium culmorum respectively. To narrow down the active principle, the most promising extracts were separated by preparative HPLC and the resulting fractions tested in bioassays. Chaetoglobosins were identified as active compounds produced by C. globosum.

CONCLUSIONS

The bioassays revealed C. aureum and C. cochliodes as promising candidates for use in biocontrol. Both showed remarkably good activity against the prominent plant pathogen P. infestans.

SIGNIFICANCE AND IMPACT OF THE STUDY

We provide the first systematic study comparing six different Chaetomium species with regard to their use as biocontrol agents.