Mycologia最新文献

Lignocellulosic biomass is a complex carbon source with recalcitrant properties whose degradation via industrial enzymatic hydrolysis is challenging, directly affecting the cost of reliable energy production. In nature, filamentous fungi, including Trichoderma species, degrade lignocellulose via an arsenal of hydrolytic and oxidative enzymes that act synergistically to process it into soluble sugar monomers. This work explored the genomic content of Trichoderma atroviride and Trichoderma harzianum strains with hydrolytic abilities by identifying regions possessing degradative enzyme-encoding genes, namely, hydrolytic clusters. We employed bacterial artificial chromosome (BAC) methodology to target specific genomic regions and explore their genetic organization, proximal gene context, and gene expression under degradative conditions. With this tool, it was possible to inspect the linear structure and expression profile of target hydrolytic-rich genomic regions. The present work offers a perspective on the organization of genome regions related to carbohydrate metabolism. This study revealed novel genes and genome regions that are positively regulated during cellulose degradation, contributing to elucidating differences in gene organization that potentially impact hydrolysis among Trichoderma species.

The impact of plant-bacterial symbioses in roots on plant-fungal interactions in distant tissues, such as leaves, remains a significant knowledge gap, particularly for tropical legume trees. In this study, we analyzed the ITS2 sequences of fungal endophytes from eight tropical Fabaceae species, differing in their ability to form root nodules, to explore patterns in foliar fungal community composition. Our findings reveal differences in fungal community richness and composition between nodulating and non-nodulating species, with non-nodulating species hosting a richer and more diverse fungal community. Specifically, non-nodulating plants supported 72 taxonomic orders and 130.5 fungal amplicon sequence variants (ASVs), compared with 45 orders and 42.7 ASVs in nodulating plants. Moreover, 40% of fungal orders were exclusive to non-nodulating species. These patterns provide insights into the diversity of fungal endophytes in tropical legumes and lay the groundwork for future research on plant-microbe interactions. This study emphasizes the need for further exploration of the ecological factors influencing fungal community composition in tropical forest ecosystems.

Spot and blight diseases are prevalent in the paddy sector, particularly in Malaysia, and are caused by the pathogens Burkholderia glumae and Curvularia lunata. To combat these issues, chemical pesticides, fungicides, and antibiotics are commonly used due to their affordability and ease of application. However, their excessive use has led to serious environmental issues, including groundwater pollution, soil contamination, and toxicity to non-target organisms. To address these concerns, nanotechnology, especially the "green synthesis" method, has recently gained attention. One approach uses metabolites from microbes as reducing agents to synthesize metal oxide nanoparticles, offering a more environmentally friendly alternative to conventional disease control methods. This study aims to explore the ability of a soil-derived fungal isolate to synthesize zinc oxide nanoparticles (ZnO-NPs) and to characterize the physicochemical properties and antimicrobial activity of the generated ZnO-NPs against paddy pathogens. In this study, a single fungal isolate capable of growing on potato dextrose agar (PDA) supplemented with 2 mM ZnSO₄·7H₂O was obtained from soil. The isolate, identified as Lecanicillium coprophilum, demonstrated the ability to synthesize ZnO-NPs. Characterization of the synthesized ZnO-NPs using various analytical techniques revealed distinct rod- and spherical shaped nanoparticles with a hexagonal wurtzite structure. Antimicrobial assessment showed that higher ZnO-NP concentrations led to greater inhibition of B. glumae and C. lunata. This study highlights the potential of green-synthesized ZnO-NPs as an eco-friendly alternative for managing paddy diseases.

Wood-boring insects play an important role in turnover of trees and biomass in temperate forests and interact with a functionally diverse mycobiome. However, the diversity and dynamics of ambrosia beetles, other wood-boring insects, and their fungi remain relatively poorly understood in the forests of temperate South America. Baseline knowledge of insect and fungal diversity is therefore needed to provide a foundation for understanding the potential future dynamics of these critically important ecosystems in the context of global change. This study aimed to document fungal diversity that could be obtained in culture from larvae, adults, and galleries of ambrosia beetles (Gnathotrupes spp.) and a carpenter moth (Chilecomadia valdiviana) from lenga (Nothofagus pumilio) in northwest Patagonia, Argentina. Long molecular barcodes from fungal cultures isolated from galleries, larvae, and adult insects were obtained using nanopore sequencing. Fungal assemblages associated with Gnathotrupes spp. (32 unique taxa) and C. valdiviana (17 unique taxa) differed in structure and composition but shared 11 distinct taxa. Differences were found between fungal assemblages associated with C. valdiviana gut tracts and galleries. Fungal assemblages found in galleries and insect bodies of Gnathotrupes varied among species, seasons, and health conditions of the host crown. Our results also showed that the ophiostomatoid fungi Raffaelea spp. and yeast Cyberlindnera sp. were commonly found with Gnathotrupes spp. whereas Ambrosiozyma angophorae and Oidiodendron sp. were found with C. valdiviana. Species of the blue stain fungi Ophiostoma patagonicum, O. nothofagi, an unidentified Sporothrix sp. and Huntiella decorticans were found with both beetles and moths, and O. patagonicum was the most frequently isolated species. This is the first comprehensive study of microbiota isolated from Gnathotrupes spp. and C. valdiviana.

The seventh part of this series devoted to the phylogeny and taxonomy of powdery mildews presents the phylogeny and taxonomy of species assigned to the genera Leveillula, Phyllactinia, Pleochaeta, and Queirozia (Erysiphaceae tribe Phyllactinieae). Phylogenetic trees based on multiple loci (ITS+28S, CAM, GADPH, GS, IGS, RPB2, and TUB) are presented. All species with available sequence data are included. The present analyses aim at providing a reference for analyses of powdery mildews of tribe Phyllactinieae. A special focus is on the generic distinction at the base of tribe Phyllactinieae and between Leveillula and Phyllactinia. The inclusion of a larger number of phylogenetically basal Phyllactinia spp. and multiple loci allowed a better insight into the phylogeny of tribe Phyllactinieae and confirmed that Leveillula spp. are nested within the Phyllactinia clade. As a consequence, Leveillula is reduced to synonymy with Phyllactinia. Additionally, Queirozia was found to be nested within the Pleochaeta clade, and as such we have reduced Queirozia to synonymy with Pleochaeta. Multiple species have been sequenced for the first time, in particular multiple North American species. Erysiphe betulae, E. orbicularis, E. polychaeta, E. saxaouli, Phyllactinia antarctica, Ph. broussonetiae-kaempferi, Ph. hamamelidis, Ph. kakicola, Ph. pyri-serotinae, Ph. salmonii, Ph. zanthoxylicola, Uncinula lynchii, and U. shiraiana are epitypified. The new species Ph. amelanchieris, sp. nov. Ph. fraxini-pennsylvanicae, sp. nov. and Ph. oemleriae, sp. nov. are described, and the new combinations Phyllactinia buddlejae, Ph. cleomes, Ph. cylindrospora, Ph. farinosa, Ph. golovinii, Ph. guilanensis, Ph. jaczewskii, Ph. lactucae-seriolae, Ph. lactucarum, Ph. lanugiosa, Ph. lappae, Ph. mindii, Ph. oxalidicola, Ph. picridis, Ph. rubiae, Ph. saxaoulii, Ph. taurica, Ph. thevenotiae, Ph. ulmi (comb. et stat. nov.), Ph. verbasci, Ph. wissadulae, and Pleochaeta erysiphoides are introduced. Furthermore, Phyllactinia sect. Basiphyllactinia, sect. nov. Phyllactinia sect. Leveillula, comb. et stat. nov. and Pleochaeta sect. Ovulariopsis, comb. et stat. nov. are presented.

Traditional microbiological methods to assess the antagonistic effect of yeasts in controlling phytopathogen fungi are often slow and based on subjective growth measurements. Therefore, isothermal microcalorimetry (IMC) is proposed as a novel, sensitive, and accurate technique that measures the heat released during the metabolic processes of microorganisms. For this reason, this study aimed to evaluate the antagonistic effect of Meyerozyma guilliermondii LMA-Cp01 on Cladosporium cladosporioides, using the mycelial growth diameter technique and IMC. The thermokinetic parameters issued from the thermogenic and thermogenic integrated curves, such as maximum growth rate, lag phase, total produced heat, and time to peak, showed variations as a function of the yeast concentration used. The deconvolution of the thermogenic curves, using the asymmetric double sigmoidal function (Asym2sig) model, allowed independent estimation of the growth of C. cladosporioides and M. guilliermondii. Pearson correlation coefficients were calculated to better understand the relationship between the two techniques. The correlations showed that the total heat of the fungal deconvoluted curves has a high correlation (larger than -0.98) with the in vitro inhibition percentage. Therefore, this study supports using IMC as an alternative to complement classical methods of fungal inhibition using yeast.

The mismanagement of wastewater containing 2,4-dichlorophenoxyacetic acid (2,4-D) is responsible for serious environmental pollution. One possible solution to this problem is the implementation of remediation techniques that use living organisms, such as fungi, to reduce herbicide levels in different matrices. This study aimed to characterize and select non-aflatoxigenic Aspergillus section Flavi strains with the ability to tolerate and remove 2,4-D in synthetic agricultural wastewater. Their aflatoxigenicity was assessed through an analytical method, followed by the amplification of the four main genes involved in aflatoxin synthesis. Four non-toxigenic strains (RCA 2, RCA 4, RCA 5, and RCA 10) tolerated up to 25 mM of the herbicide and were subsequently identified as A. oryzae. An ecophysiological assay revealed that the best conditions for their growth were 1 mM of 2,4-D at pH 7 and 25 C, and that only one set of conditions (5 mM of 2,4-D, pH 9, and 25 C) completely inhibited development in one of the strains. Finally, removal assays were performed in synthetic wastewater, in which residual 2,4-D levels were quantified by high-performance liquid chromatography ultraviolet detection (HPLC-UV) and tandem mass spectrometry (MS/MS). Three of the four A. oryzae strains removed over 40% of the herbicide in the medium after 7 d of incubation, and close to or more than 60% after 14 d. Therefore, these strains could potentially be considered for the design of bioaugmentation strategies aimed at reducing 2,4-D contamination in wastewater.

Many morning glories (family Convolvulaceae) contain ergot alkaloids-important bioactive compounds produced exclusively by fungi. The ergot alkaloids of the few investigated morning glories are associated with the presence of a symbiotic Clavicipitaceous fungus. The genus Periglandula (Clavicipitaceae) was erected recently for two epibiotic species of morning glory symbionts. Biochemical and limited sequence data indicate that Ipomoea tricolor, a commonly cultivated morning glory from Mexico, contains a Periglandula species, but no signs of the fungus have ever been detected. Our goal was to isolate and describe this fungus, which we hypothesize represents a new species. Observation of fungal hyphae in evacuated seed coats of I. tricolor and subsequent transfer onto malt extract agar resulted in cultures of the symbiont isolated from the plant. The fungus grew slowly as white hyphae and sometimes aggregated into synnema-like structures, both of which lacked spores. We isolated sufficient DNA to sequence the genome with Illumina technology. Phylogenetic analyses based on multiple genes indicated that the symbiont of I. tricolor was distinct from, but related to, the two described species of Periglandula previously observed in other species of morning glories. Using quantitative polymerase chain reaction (qPCR), the fungus was quantified most abundantly in hypocotyls of I. tricolor, with lesser quantities in stems, cotyledons, and leaves. The fungus was not detected in roots, although ergot alkaloids were abundant in all tissues including roots. We conclude that the symbiotic fungus of I. tricolor is a distinct species of Periglandula and propose the name Periglandula clandestina, sp. nov.

Melanins are the pigments with diverse protective functions in a wide range of organisms. The ability of lichens to synthesize melanins is an important adaptation in response to adverse light conditions, including ultraviolet (UV) irradiation and high light. Previously, we demonstrated that melanization of the lichen Lobaria pulmonaria is accompanied by the accumulation of melanin granules in the upper cortex. However, very little information is available on the morphology and physicochemical properties of these particles. Here, for the first time, we used polyclonal antibodies against eumelanin to visualize melanin in the upper cortex of L. pulmonaria and confirm its identity. Using scanning electron microscopy, we showed that extracted melanins are large, spherical aggregates, with an average size of 230 nm. The aggregates had an irregular and unstable structure and displayed high adhesive properties, according to atomic force microscopy. Purification using size exclusion chromatography showed that melanins coeluted with polysaccharides. Purified particles were visualized as discrete structures (subaggregates) with an average size of 42 nm and displayed higher stability and lower adhesive properties than non-purified aggregates. In colloidal aqueous systems, melanin particles formed aggregates with particle sizes of 279 and 212 nm for the non-purified and purified samples, respectively, suggesting that the removal of the polysaccharide component during purification causes the condensation of the polyaromatic structure of melanin. Taken together, our results suggest that melanin particles extracted from UV-melanized thalli of the lichen L. pulmonaria comprise a supramolecular assembly of melanin and polysaccharides. Analysis of the size, ζ-potential, and polydispersity index suggests that melanin particles are capable of structural rearrangements that lead to changes in their nanomechanical properties. The ability of the melanin to bind to polysaccharides may enhance the structural robustness of mycobiont cell walls and increase the tolerance of lichen thalli to stressful environments.

Didymellaceae is one of the largest families in the Pleosporales, encompassing main genera of Phoma-like fungi including Ascochyta, Didymella, and Stagonosporopsis and representing underestimated biodiversity. Plants in the Convolvulaceae often grow as weeds in many climates and host a wide range of fungi in the Didymellaceae. This study identified 22 Didymellaceae strains isolated from plants in the Convolvulaceae according to the consolidated species concept (CSC) using phylogenetic, micromorphological, and cultural features. Multilocus phylogenetic analysis inferred from nucleotide sequences of the internal transcribed spacer (ITS), large subunit (28S) of ribosomal DNA, partial DNA-directed RNA polymerase II subunit (rpb2), and β-tubulin (tub2) genes revealed well-supported monophyletic clades corresponding to 16 Didymellaceae species. Reported here for the first time from the Convolvulaceae hosts are Didymella americana, D. bellidis, D. glomerata, D. pomorum, D. segeticola, D. sinensis, D. tanaceti, Nothophoma brennandiae, N. gossypiicola, Phomatodes nebulosa, Stagonosporopsis caricae, S. heliopsidis, and S. inoxydabilis. Additionally, three new species were described: Didymella pseudomacrophylla, sp. nov. Epicoccum convolvulicola, sp. nov. and Epicoccum pseudoplurivorum, sp. nov. Seven species are reported for the first time from Russia: D. bellidis, D. segeticola, D. sinensis, D. tanaceti, N. brennandiae, P. nebulosa, and S. caricae, and one species, S. heliopsidis, for the first time from Kazakhstan.