Journal of Fungi最新文献

Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense (Foc), is a destructive vascular disease that seriously threatens global banana production. To investigate the contribution of histidine metabolism to Foc growth and pathogenicity, we functionally characterized FoHis2, a putative histidinol-phosphate phosphatase in Foc race 4 (Foc4). Targeted deletion of FoHis2 severely compromised histidine prototrophy, with the ΔFoHis2 mutant growing slowly on potato dextrose agar and even more slowly on minimal medium (MM, no histidine added). Exogenous histidine fully restored the mutant growth to wild-type (WT) levels, whereas histidinol supplementation rescued the colony size but not the reduced aerial mycelium formation. The ΔFoHis2 mutant exhibited markedly reduced vegetative growth and hyphal branching, and increased sensitivity to elevated H₂O₂ concentrations, compared with the WT strain. Consistent with the oxidative stress phenotype, peroxisome-associated genes were down-regulated in the ΔFoHis2 mutant. FoHis2 was dispensable for conidiation, cell wall integrity, and fusaric acid and beauvericin biosynthesis. Pathogenicity assays showed that the deletion of FoHis2 severely compromised cellophane penetration and greatly reduced disease incidence and severity on Cavendish banana plantlets, whereas genetic complementation restored the WT phenotypes. These results indicate that FoHis2-mediated histidine biosynthesis is essential for metabolic homeostasis, stress adaptation, and full virulence in Foc4, and highlight histidine metabolism as a potential target for controlling Fusarium wilt in banana.

The fungal pathogen Metschnikowia bicuspidata causes "milky disease" in the Chinese mitten crab (Eriocheir sinensis), which poses substantial challenges to sustainable aquaculture development considering the current lack of effective treatment interventions. To address this issue, in laboratory validation, we developed two rapid recombinase polymerase amplification (RPA) detection methods for M. bicuspidata in E. sinensis targeting the histone acetyltransferase B-type subunit 2 gene (HAT-B2): an electrophoretic assay (RPA-AGE) and a colloidal gold lateral flow dipstick assay (RPA-LFD). We optimized RPA-AGE and RPA-LFD protocols for specific pathogen detection. Target detection was achieved within 35 min using RPA-AGE (30 min amplification at 37 °C followed by 5 min agarose gel electrophoresis), whereas RPA-LFD provided results in 15 min with high specificity (10 min amplification at 37 °C plus 5 min strip reading). Both methods exhibited exclusive specificity to M. bicuspidata, with no cross-reactivity with six pathogens, including Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, Candida albicans, Saccharomyces cerevisiae, and Microsporidia sp. The detection sensitivity of both platforms reached 4.8 copies/μL in laboratory validation. For field testing, the detection results from 30 field samples showed that although the 70% detection rate was lower than the 83.3% achieved by quantitative PCR, these approaches surpassed the detection rate of conventional PCR (53.3%). Notably, the RPA-LFD platform is applicable under field conditions as no specialized equipment is required. These rapid, sensitive, and specific detection systems provide practical tools for the early diagnosis and containment of M. bicuspidata infections in aquaculture settings.

Cordycepin is a key active component of Cordyceps militaris, but the molecular mechanism underlying temperature-regulated biosynthesis remains unclear. In this study, Cordyceps militaris strain KN-1 was used as experimental material, with low-temperature (15 °C), control (20 °C), and high-temperature (25 °C) treatments applied during the fruiting body stage. Transcriptomics, untargeted metabolomics, weighted gene co-expression network analysis (WGCNA), and Reverse Transcription quantitative PCR (RT-qPCR) validation were integrated to elucidate the molecular mechanism of temperature-mediated cordycepin biosynthesis. The results showed that 25 °C increased fruiting body cordycepin content by 84%, while 15 °C reduced it. Transcriptomic analysis identified differentially expressed genes (DEGs) enriched in transmembrane transport and fatty acid metabolism, and untargeted metabolomics revealed differential metabolites (DAMs) enriched in lipids and organic acids, indicating that temperature primarily affects Cordyceps militaris membrane function. WGCNA showed that the MEblue module was positively correlated with cordycepin (r = 0.93), with Major Facilitator Superfamily (MFS) members accounting for the highest proportion (47.1%) that may affect cordycepin transmembrane transport. Multi-omics analysis indicated that high temperature promotes cordycepin accumulation through the synergistic regulation of multiple pathways: upregulating genes in the pentose phosphate pathway, purine metabolism, and cordycepin biosynthetic gene cluster (Cns1-Cns3), increasing protective agent pentostatin content, downregulating cordycepin-degrading genes, and enhancing cordycepin transmembrane transport. This study clarifies the molecular mechanism of temperature-mediated cordycepin accumulation, providing a theoretical basis for improving cordycepin production via temperature regulation, optimizing Cordyceps militaris strain quality, and facilitating efficient industrial production.

Although RNA sequencing (RNA-seq) enables rapid transcriptome profiling, functional annotation of fungal transcriptomes remains challenging. Existing tools prioritize broad taxonomic coverage, and reference genomes are scarce for non-model species. This study aimed to develop a fungal-specific functional annotation workflow to support rapid and accurate functional analyses downstream of RNA-seq, independent of reference genome availability. To evaluate the workflow, RNA-seq data from 57 samples of Lentinula edodes strain H600 (shiitake mushroom) were retrieved, along with full-length transcript sequencing (Iso-Seq) data and corresponding RNA-seq data from 20 samples of Phakopsora pachyrhizi (Asian soybean rust) from public databases. The workflow successfully annotated over 96% of protein-coding transcripts and demonstrated applicability to Iso-Seq data. Functional enrichment analyses revealed higher-resolution functional detection than existing annotation tools. Furthermore, integrating homology searches against fungal-specific databases with expression pattern-based annotations highlighted the workflow's utility for target identification in genome editing and other applications. Overall, the results of this study highlight the potential of the developed workflow in facilitating the discovery of functionally important transcripts and their translation into biotechnological applications.

Species of the ascomycetous genus Cladobotryum (Hypocreales, Hypocreaceae) are ecologically and economically important mycoparasites that cause cobweb disease in cultivated and wild mushrooms. Despite their significance as fungal pathogens and producers of bioactive metabolites, the taxonomy of Cladobotryum remains unresolved due to extensive morphological plasticity, complex teleomorph-anamorph connections, and the presence of cryptic species. This study employs an integrative approach combining micro- and macromorphological characterization, multi-locus phylogeny (ITS, rpb2, and tef-1a), and comparative genomics to clarify the taxonomic position of the Greek isolate Cladobotryum sp. ATHUM 6904, previously designated as an unclassified red-pigmented (URP) strain. Phylogenetic analyses demonstrated that URP strains form a distinct, well-supported clade closely related to C. tenue and C. rubrobrunnescens, yet genetically and morphologically distinct from both. Comparative genomic analyses of isolate ATHUM 6904 and the ex-type strains of C. tenue and C. rubrobrunnescens revealed pronounced divergence in transposable element content, mitochondrial genome architecture, gene order, orthologous gene composition, secondary metabolite biosynthetic potential, and overall genomic distance. Micro- and macromorphological comparisons further supported the differentiation of isolate ATHUM 6904 from both reference species. Based on the combined molecular, morphological, and genomic evidence, the Greek isolate ATHUM 6904 is described as a novel species, Cladobotryum rhodochroum sp. nov.

Sphingolipids are a class of amphipathic lipids characterized by a sphingoid base backbone, which can be classified into glycosphingolipids and sphingomyelins. They exhibit structural complexity and functional diversity, being widely distributed in eukaryotes and some bacterial species. Sphingolipids are important regulators of signal transduction and cellular homeostasis and are involved in numerous biological processes, including cell polarity establishment, energy metabolism, proliferation, and differentiation. However, research on fungal sphingolipids remains limited. This review provides an overview of sphingolipid species, structural features, and their biosynthesis and degradation in fungi. It also summarizes their essential functions in maintaining cell membrane structure, influencing morphological development, pathogenicity, and homeostasis, and participating in apoptosis. Additionally, the potential of antifungal agents targeting the sphingolipid pathway and their application prospects are discussed. Finally, current challenges and future directions in fungal sphingolipid research are highlighted to support the investigation of their mechanisms and the development of antifungal therapies targeting sphingolipid metabolic pathways.

Barnyard grass, a widespread and persistent weed in rice paddies, belongs to the same family as rice and may act as a bridge host for the rice blast fungus. This study utilized comparative genomics to analyze six Pyricularia oryzae strains isolated from barnyard grass (Baicao series) and rice (GDYJ7 and ZJX18), integrating pathogenicity assays, whole-genome sequencing, and functional annotation. Pathogenicity tests demonstrated host specificity, as Baicao series strains caused typical lesion symptoms on barnyard grass but not on rice leaves, while GDYJ7 and ZJX18 caused lesions mainly on rice. Genomic analyses indicated that Baicao series strains possessed larger genomes (41.04 Mb to 41.16 Mb) with a higher content of repetitive sequences (6.68% to 7.09%) compared to rice strains GDYJ7 and ZJX18 (38.69 Mb and 39.05 Mb; 3.66% and 3.71% repeats). Phylogenetic analysis confirmed that Baicao series strains represent a grass-infecting pathotype of P. oryzae species, as they were grouped with the established grass-isolated P. oryzae strains, while GDYJ7 and ZJX18 were grouped with rice-isolated P. oryzae strains. However, Baicao series, GDYJ7 and ZJX18 are all relatively distant from P. grisea species. PCR amplification revealed that Baicao series strains harbored significantly fewer avirulence genes (Avr-Pib, Avr-Pizt, PWL3) than GDYJ7 and ZJX18 (Avr-Pib, Avr-Pizt, Avr-Pi9, Avr-Pik, PWL2), with Baicao9 retaining only Avr-Pib. In summary, our results suggested that the genomic sequences of the barnyard grass-isolated strains serve as a valuable resource for the study of P. oryzae strains with differential host preference and provide novel insights into the evolution of pathogen genomes during host adaptation.

Protein phosphorylation modification plays a role in cells' response to oxidative stress, a key factor leading to postharvest browning of Flammulina filiformis. However, the molecular mechanism by which protein phosphorylation contributes to postharvest browning of F. filiformis remains unclear. This study aimed to characterize the basal phosphoproteomic landscapes associated with variations in different browning phenotypes of F. filiformis. Using data-independent acquisition (DIA) mass spectrometry, we comprehensively profiled the phosphorylation dynamics in susceptible-to-browning (SB) and resistant-to-browning (RB) cultivars at harvest and after 24 h storage. We identified 84,244 phosphorylation sites on 4494 phosphoproteins, with the SB cultivar displaying more altered sites (21,195) than the RB (16,087). Functional enrichment analysis revealed that the differential phosphorylation was significantly implicated in kinases and energy metabolism pathways. Notably, the SB cultivar exhibited a more pronounced phosphorylation profile on key proteins involved in ATP synthesis and glycolysis. Protein-protein interaction (PPI) network analysis further indicated a kinase-mediated regulatory network targeting core energy metabolism components, including ATP synthase and 6-phosphofructokinase. This distinct phosphosignature in the SB cultivar correlated with its more severe browning phenotype and a sharper decline in ATP content during storage. Our findings suggest that divergent phosphorylation-mediated regulation of energy metabolism is strongly associated with the differential postharvest browning susceptibility between these two cultivars, providing a valuable molecular resource for future functional studies.

Soil alkalinization constitutes a significant abiotic stress factor that severely constrains global agricultural productivity. The application of alkali-tolerant endophytes represents a promising strategy for enhancing crop resilience. This study focused on the isolation and characterization of alkali-resistant endophytic fungi derived from wild soybean (Glycine soja), aiming to elucidate their potential in promoting host plant growth and to investigate their molecular responses to alkali stress. From an initial collection of 39 wild soybean endophytic fungal isolates, 12 strains demonstrated significant alkali tolerance, as evidenced by increased mycelial dry weight under both mild and intense alkali stress. Among these, two strains, designated WDR2 and WDR5, demonstrated particularly pronounced biomass enhancement and were taxonomically identified as Fusarium verticillioides through comprehensive morphological and molecular analyses. Subsequent inoculation assays conducted on maize (Zea mays) revealed that both fungal strains significantly alleviated the inhibitory effects of alkali stress on root system architecture. Comparative evaluations in soybean indicated that the growth-promoting effects of these endophytes were host-specific and varied according to fungal strain, stress intensity, and inoculation timing. Transcriptomic profiling via RNA-Seq under mild alkali stress identified 589 and 182 differentially expressed genes (DEGs) in WDR2 and WDR5, respectively, with only 43 DEGs shared between the two strains, indicating largely strain-specific transcriptional adaptations. Functional enrichment analysis revealed several shared mechanisms underlying alkaline adaptation in both fungi species, including the maintenance of ion homeostasis, remodeling of the cell wall, and regulation of protein complex assembly and oxidative stress responses. Moreover, distinct metabolic adaptations were identified: WDR2 exhibited significant enrichment in cellular integrity and modulation of membrane-related processes, as well as amino sugar and nucleotide sugar metabolism pathways. In contrast, WDR5 was enriched in phosphate ion transport and related transporter functions, glycerol kinase activity, and glycerolipid and glutathione metabolism. In summary, this study successfully identified two novel alkali-tolerant wild soybean endophytic fungi, WDR2 and WDR5. The results provide valuable insights into their divergent molecular adaptation strategies and highlight their potential application as bio-inoculants to enhance crop productivity in alkaline soils.

Villosiclava virens (anamorph: Ustilaginoidea virens) is a fungal pathogen that causes rice false smut, one of the most devastating diseases of rice. The Uvpks1 gene encoding polyketide synthase is responsible for the biosynthesis of ustilaginoidins, a major group of mycotoxins in V. virens. In this study, three strains, including the Uvpks1 deletion mutant ΔUvpks1, the complementation strain ΔUvpks1-C1, and the wild-type isogenic strain P1 of V. virens, were employed to investigate the role of Uvpks1 in shaping the metabolic profile and in the development, stress responses, and pathogenicity of V. virens. The deletion of Uvpks1 led to both the elimination of ustilaginoidin biosynthesis and the induction of many other secondary metabolite biosynthetic pathways. It decreased mycelial growth and sporulation, fungal tolerance to Congo red-induced cell wall damage stress, and susceptibility to the fungicides epoxiconazole and prochloraz. Meanwhile, it increased hyphal hydrophobicity, resistance to H₂O₂-induced oxidative stress and metal cation stress, and susceptibility to the fungicide azoxystrobin. Furthermore, the deletion of Uvpks1 resulted in reduced fungal pathogenicity toward rice plants. The findings reveal the functions of Uvpks1 in shaping the metabolic profile, development, stress responses, and pathogenicity of V. virens, which will be beneficial for developing new strategies to control rice false smut and ustilaginoidins.