Ima Fungus最新文献

Leafcutter ants farm a fungal cultivar (Leucoagaricus gongylophorus) that converts inedible vegetation into food that sustains colonies with up to millions of workers. Analogous to edible fruits of crops domesticated by humans, L. gongylophorus has evolved specialized nutritional rewards-swollen hyphal cells called gongylidia that package metabolites and are consumed by ant farmers. Yet, little is known about how gongylidia form, and thus how fungal physiology and ant provisioning collectively govern farming performance. We explored the process of gongylidium formation using advanced microscopy to image the cultivar at scales of nanometers, and both in vitro experiments and in silico analyses to examine the mechanisms of gongylidia formation when isolated from ant farmers. We first used transmission electron, fluorescence, and confocal microscopy imaging to see inside hyphal cells. This imaging showed that the cultivar uses a process called autophagy to recycle its own cellular material (e.g. cytosol, mitochondria) and then shuttles the resulting metabolites into a vacuole whose continual expansion displaces other organelles and causes the gongylidium cell's bulging bulb-like appearance. We next used scanning electron microscopy and light microscopy to link this intracellular rearrangement to the external branching patterns of gongylidium cells as they clump together into edible bundles called staphyla. We next confirmed that autophagy plays a critical role in gongylidium formation both: (1) in vitro as gongylidium suppression occurred when isolated fungal cultures were grown on media with autophagy inhibitors, and (2) in silico as differential transcript expression (RNA-seq) analyses showed upregulation of multiple autophagy gene isoforms in gongylidia relative to undifferentiated hyphae. While autophagy is a ubiquitous and often highly derived process across the tree of life, our study reveals a new role for autophagy as a mechanism of functional integration between ant farmers and their fungal crop, and potentially as a signifier of higher-level homeostasis between uniquely life-time committed ectosymbionts.

Among molecular-based techniques for fungal identification, Sanger sequencing of the primary universal fungal DNA barcode, the internal transcribed spacer (ITS) region (ITS1, 5.8S, ITS2), is commonly used in clinical routine laboratories due to its simplicity, universality, efficacy, and affordability for fungal species identification. However, Sanger sequencing fails to identify mixed ITS sequences in the case of mixed infections. To overcome this limitation, different high-throughput sequencing technologies have been explored. The nanopore-based technology is now one of the most promising long-read sequencing technologies on the market as it has the potential to sequence the full-length ITS region in a single read. In this study, we established a workflow for species identification using the sequences of the entire ITS region generated by nanopore sequencing of both pure yeast isolates and mocked mixed species reads generated with different scenarios. The species used in this study included Candida albicans (n = 2), Candida tropicalis (n = 1), Nakaseomyces glabratus (formerly Candida glabrata) (n = 1), Trichosporon asahii (n = 2), Pichia kudriavzevii (formerly Candida krusei) (n = 1), and Cryptococcus neoformans (n = 1). Comparing various methods to generate the consensus sequence for fungal species identification, the results from this study indicate that read clustering using a modified version of the NanoCLUST pipeline is more sensitive than Canu or VSEARCH, as it classified species accurately with a lower abundance cluster of reads (3% abundance compared to 10% with VSEARCH). The modified NanoCLUST also reduced the number of classified clusters compared to VSEARCH, making the subsequent BLAST+ analysis faster. Subsampling of the datasets, which reduces the size of the datasets by approximately tenfold, did not significantly affect the identification results in terms of the identified species name, percent identity, query coverage, percentage of reads in the classified cluster, and the number of clusters. The ability of the method to distinguish mixed species within sub-populations of large datasets has the potential to aid computer analysis by reducing the required processing power. The herein presented new sequence analysis pipeline will facilitate better interpretation of fungal sequence data for species identification.

Fucose is a deoxyhexose sugar present and studied in mammals. The process of fucosylation has been the primary focus in studies relating to fucose in animals due to the presence of fucose in Lewis antigens. Very few studies have reported its presence in Fungi, mostly in Mucoromycotina. The constitution of 25% and 12% of this sugar in the carbohydrates of cell wall in the respective Umbelopsis and Mucorales strains boosts the need to bridge the gap of knowledge on fucose metabolism across the fungal tree of life. In the absence of a network map involving fucose proteins, we carried out an in-silico approach to construct the fucose metabolic map in Fungi. We analyzed the taxonomic distribution of 85 protein families in Fungi including diverse early diverging fungal lineages. The expression of fucose-related protein-coding genes proteins was validated with the help of transcriptomic data originating from representatives of early diverging fungi. We found proteins involved in several metabolic activities apart from fucosylation such as synthesis, transport and binding. Most of the identified protein families are shared with Metazoa suggesting an ancestral origin in Opisthokonta. However, the overall complexity of fucose metabolism is greater in Metazoa than in Fungi. Massive gene loss has shaped the evolutionary history of these metabolic pathways, leading to a repeated reduction of these pathways in most yeast-forming lineages. Our results point to a distinctive mode of utilization of fucose among fungi belonging to Dikarya and the early diverging lineages. We speculate that, while Dikarya used fucose as a source of nutrients for metabolism, the early diverging group of fungi depended on fucose as a building block and signaling compound.

Araucaria araucana is an ancient conifer, native to the mountain ranges in Chile and Argentina. These trees host a large number of organisms, mainly insects, strongly or even exclusively associated with them. The recent emergence of a novel canker disease on A. araucana has emphasised the importance of fungi associated with these iconic trees and has resulted in the discovery of various new species. In this study, we considered the identity of an unknown calicioid fungus consistently found on resin on the branches of A. araucana. Preliminary phylogenetic analyses placed isolates in the recently described sub-class Cryptocaliciomycetidae, closest to Cryptocalicium blascoi. However, the morphology of the ascomata and its occurrence in a unique niche suggested that the closest relative could be Resinogalea humboldtensis (Bruceomycetaceae, incertae sedis), a fungus with similar sporing structures found on resin of Araucaria humboldtensis in New Caledonia. There are no living cultures or sequence data available for either R. humboldtensis or its supposed closest relative, Bruceomyces castoris, precluding sequence-based comparisons. Morphological comparisons of the sporing structures on A. araucana confirmed that the ascomatal morphology of our unknown calicioid fungus and R. humboldtensis are almost identical and resemble each other more so than B. castoris or Cr. blascoi. A phylogenetic analysis based on the small subunit (SSU), internal transcribed spacer (ITS) and large subunit (LSU) rDNA regions resolved our strains into two clades with Cr. blascoi as its closest relative. Further analyses applying the Genealogical Concordance Phylogenetic Species Recognition (GCPSR) based on ITS, mini chromosome maintenance protein complex (MCM7), RNA polymerase II second largest subunit (RPB2) and translation elongation factor 1-alpha (TEF) gene regions, confirmed that strains represent two new species. Based on our morphological observations and phylogenetic analyses, we introduce two new Resinogalea species, R. araucana and R. tapulicola, and reclassify the genus in the subclass Cryptocaliciomycetidae.

During the construction and assembly of the Mars 2020 mission components at two different NASA cleanrooms, several fungal strains were isolated. Based on their colony morphology, two strains that showed yeast-like appearance were further characterized for their phylogenetic position. The species-level classification of these two novel strains, using traditional colony and cell morphology methods combined with the phylogenetic reconstructions using multi-locus sequence analysis (MLSA) based on several gene loci (ITS, LSU, SSU, RPB1, RPB2, CYTB and TEF1), and whole genome sequencing (WGS) was carried out. This polyphasic taxonomic approach supported the conclusion that the two basidiomycetous yeasts belong to hitherto undescribed species. The strain FJI-L2-BK-P3^T, isolated from the Jet Propulsion Laboratory Spacecraft Assembly Facility, was placed in the Naganishia albida clade (Filobasidiales, Tremellomycetes), but is genetically and physiologically different from other members of the clade. Another yeast strain FKI-L6-BK-PAB1^T, isolated from the Kennedy Space Center Payload Hazardous and Servicing Facility, was placed in the genus Cystobasidium (Cystobasidiales, Cystobasidiomycetes) and is distantly related to C. benthicum. Here we propose two novel species with the type strains, Naganishia kalamii sp. nov. (FJI-L2-BK-P3^T = NRRL 64466 = DSM 115730) and Cystobasidium onofrii sp. nov. (FKI-L6-BK-PAB1^T = NRRL 64426 = DSM 114625). The phylogenetic analyses revealed that single gene phylogenies (ITS or LSU) were not conclusive, and MLSA and WGS-based phylogenies were more advantageous for species discrimination in the two genera. The genomic analysis predicted proteins associated with dehydration and desiccation stress-response and the presence of genes that are directly related to osmotolerance and psychrotolerance in both novel yeasts described. Cells of these two newly-described yeasts were exposed to UV-C radiation and compared with N. onofrii, an extremophilic UV-C resistant cold-adapted Alpine yeast. Both novel species were UV resistant, emphasizing the need for collecting and characterizing extremotolerant microbes, including yeasts, to improve microbial reduction techniques used in NASA planetary protection programs.

The Microsporum canis complex consists of one zoophilic species, M. canis, and two anthropophilic species, M. audouinii and M. ferrugineum. These species are the most widespread zoonotic pathogens causing dermatophytosis in cats and humans worldwide. To clarify the evolutionary relationship between the three species and explore the potential host shift process, this study used phylogenetic analysis, population structure analysis, multispecies coalescent analyses, determination of MAT idiomorph distribution, sexual crosses, and macromorphology and physicochemical features to address the above questions. The complex of Microsporum canis, M. audouinii and M. ferrugineum comprises 12 genotypes. MAT1-1 was present only in M. canis, while the anthropophilic entities contained MAT1-2. The pseudocleistothecia were yielded by the mating behaviour of M. canis and M. audouinii. Growth rates and lipase, keratinolysis and urea hydrolytic capacities of zoophilic M. canis isolates were all higher than those of anthropophilic strains; DNase activity of M. ferrugineum exceeded that of M. canis. The optimum growth temperature was 28 °C, but 22 °C favoured the development of macroconidia. Molecular data, physicochemical properties and phenotypes suggest the adaptation of zoophilic M. canis to anthropophilic M. ferrugineum, with M. audouinii in an intermediate position.

Cordyceps is a diverse genus of insect pathogenic fungi, with about 180 accepted species, including some well-known ones used as ethnic medicine and/or functional food. Nevertheless, mitogenomes are only available for four members of the genus. The current study reports the mitogenome of Cordyceps blackwelliae, a newly described entomopathogenic fungus. The 42,257-bp mitogenome of the fungus encoded genes typically found in fungal mitogenomes, and a total of 14 introns inserted into seven genes, including cob (1 intron), cox1 (4), cox3 (3), nad1 (1), nad4 (1), nad5 (1), and rnl (3). RNA-Seq analysis revealed differential expression of mitochondrial genes and supported annotations resulting from in silico analysis. There was clear evidence for polycistronic transcription and alternative splicing of mitochondrial genes. Comparison among mitogenomes of five different Cordyceps species (i.e., C. blackwelliae, C. chanhua, C. militaris, C. pruinosa, and C. tenuipes) revealed a high synteny, with mitogenome size expansion correlating with intron insertions. Different mitochondrial protein-coding genes showed variable degrees of genetic differentiation among these species, but they were all under purifying selection. Mitochondrial phylogeny based on either nucleotide or amino acid sequences confirmed the taxonomic position of C. blackwelliae in Cordycipitaceae, clustering together with C. chanhua. This study promotes our understanding of fungal evolution in Cordyceps.

Although there is a continuous increase in available molecular data, not all sequence identities in public databases are always properly verified and managed. Here, the sequences available in GenBank for Fuscoporia (Hymenochaetales) were validated. Many morphological characters of Fuscoporia overlap among the species, emphasizing the role of molecular identification for accuracy. The identities of 658 Fuscoporia GenBank internal transcribed spacer (ITS) sequences were assessed using ITS phylogeny, revealing 109 (16.6%) misidentified and 196 (29.8%) unspecified sequences. They were validated and re-identified based on the research articles they were published in and, if unpublished, based on sequences from the type, type locality-derived sequences, or otherwise reliable sequences. To enhance the resolution of species delimitation, a phylogenetic assessment of a multi-marker dataset (ITS + nrLSU + rpb2 + tef1) was conducted. The multi-marker phylogeny resolved five of the twelve species complexes found in the ITS phylogeny and uncovered five new Fuscoporia species: F. dolichoseta, F. gilvoides, F. koreana, F. reticulata, and F. semicephala. The validated ITS sequences in this study may prevent further accumulation of misidentified sequences in public databases and contribute to a more accurate taxonomic evaluation of Fuscoporia species.

The genus is a special and crucial taxonomic rank compared with others above the species level, because a species has to be placed in a certain genus instead of any other higher ranks. With more and more new species being described, the placements of their generic position are sometimes incorrect due to the simple phylogenies resulting from inappropriate sampling. Here, we focus on the taxonomy of a small wood-inhabiting fungal genus Hyphodermella. With the most comprehensive sampling to date, the phylogenetic position of Hyphodermella within Phanerochaetaceae is rearranged by employing the same ITS and nLSU regions as in previous studies and also the ITS, nLSU, rpb1, rpb2 and tef1α regions. Three species are excluded from Hyphodermella: H. poroides is placed in a newly introduced monotypic genus Pseudohyphodermella, while H. aurantiaca and H. zixishanensis are transferred to Roseograndinia. Hyphodermella suiae is described as a new species from South China and Vietnam. Keys to eight species in Hyphodermella and five in Roseograndinia are provided. Beyond solving the taxonomic issue of Hyphodermella itself, the current study also aims to suggest that all fungal taxonomists especially beginners should keep in mind to sample as many comprehensive taxa as possible in phylogenetic analyses.

Some Ophiocordyceps species infecting ants are able to manipulate the host behavior. The hosts are manipulated in order to move to location that are advantageous for fungal spore transmission. Ophiocordyceps species that are able to manipulate the ant's behavior are called "zombie-ant fungi". They are widespread within tropical forests worldwide, with relatively few reports from subtropical monsoon evergreen broad-leaf forest. Zombie-ant fungi have been described and reported in different countries worldwide. However, there were a few reports from China. This study proposed six new species of zombie-ant fungi from China based on multi-gene (SSU, LSU, TEF, RPB1 and RPB2) phylogenetic analyses and morphological characteristics. Six novel species of Ophiocordyceps from China were identified as the Ophiocordyceps unilateralis core clade, forming a separate lineage with other species. Six novel species of Ophiocordyceps with hirsutella-like asexual morphs exclusively infecting ants were presented herein, namely, Ophiocordyceps acroasca, Ophiocordyceps bifertilis, Ophiocordyceps subtiliphialida, Ophiocordyceps basiasca, Ophiocordyceps nuozhaduensis and Ophiocordyceps contiispora. Descriptions and illustrations for six taxon were provided. Five of these species were collected from the subtropical monsoon evergreen broad-leaf forest, and one was collected from the rainforest and subtropical monsoon evergreen broad-leaf forest. This work proposes that the same host of Camponotus can be infected by multiple ant pathogenic fungi, while multiple ants of Polyrhachis can be infected by the same pathogenic fungi at the same time. This study contributes towards a better understanding of the evolutionary relationship between hosts and fungi, and provides novel insights into the morphology, distribution, parasitism, and ecology of Ophiocordyceps unilateralis sensu lato. We have provided a method for obtaining living cultures of Ophiocordyceps unilateralis complex species and their asexual morphs based on the living cultures, which is of significant value for further studies of Ophiocordyceps unilateralis complex species in the future.