Frontiers in fungal biology最新文献

Introduction: Given the growing recognition of Fomitopsis betulina for its bioactive potential, the influence of cultivation parameters on its mycelial development, metabolite production in submerged culture, and associated antioxidant activity remains insufficiently explored.

Methods: This study investigated the effects of various cultivation parameters on biomass accumulation, total phenolic content (TPC), and free radical scavenging activity, assessed using the Folin-Ciocalteu and DPPH assays respectively.

Results and discussion: Among solvents tested, methanol and 70% ethanol were most effective for phenolic extraction, yielding 20.54±0.11 and 19.39±0.14mg GAE/g, respectively, while some solvents demonstrated strong DPPH inhibition (≥90%). A cultivation at 25°C supported optimal biomass accumulation (5.23±0.10g/L), phenolic compound total yield (101.10mg GAE/L), and antioxidant activity (91.66±0.40%). Static cultivation conditions promoted surface mycelial growth and resulted in the highest biomass yield (5.28±0.15g/L), strong DPPH inhibition (≥90%), and phenolic synthesis (101.75mg GAE/L). Among carbon sources, maltose favored biomass formation, whereas xylose led to the highest DPPH inhibition (89.68±0.91%) and TPC (16.08±0.06mg GAE/g; total yield: 15.92mg GAE/L). Of the nitrogen sources evaluated, ammonium sulfate supported the greatest biomass accumulation (2.64±0.21g/L), while ammonium nitrate enhanced antioxidant activity (80.54±3.10%). Although urea produced the highest TPC per gram of dry biomass (11.32±0.05mg GAE/g), ammonium sulfate resulted in the highest phenolic total yield (18.43mg GAE/L). An initial medium pH of 6.0 was identified as optimal for maximizing biomass growth, phenolic compound production, and antioxidant capacity. The cultivation parameters were ranked in order of influence as: temperature > duration of static cultivation > pH > duration of agitation > carbon source > nitrogen source. These findings provide a foundation for the targeted optimization of cultivation conditions to enhance biomass production, phenolic compound accumulation, and antioxidant activity in F. betulina (GenBank accession: PQ184655). The results contribute to the broader understanding of fungal secondary metabolite production and support future applications in biotechnology and functional food development. .

Plants establish environmental connections through mycorrhizal symbiosis. These relationships enable them to obtain nutrients and cope with stress while simultaneously exchanging information through subterranean networks. A unified understanding of the molecular mechanisms underlying mycorrhizal interactions that drive adaptation and survival has not yet been achieved, in part because research on them stems from diverse fields of research, such as mycorrhizal ecology and plant epigenetics. This review presents recent studies demonstrating that epigenetic control serves as a central system enabling plants to adapt and maintain stable relationships with mycorrhizal fungi. We begin by describing different types of mycorrhizae. We then analyze mycorrhizal symbiosis by integrating plant and fungal genomic data with molecular evidence on DNA methylation, histone modification, chromatin remodeling, and small RNA pathways. We demonstrate that mycorrhizal symbiosis depends on changing chromatin states, which influence the regulation of the establishment, maintenance, and efficiency of symbiotic connections. They also regulate the balance between nutrient uptake and defense. They may underlie mycorrhizal stress and transgenerational "memory." We review studies showing that RNA interference between different species enables reorganization of gene expression between plant and fungal cells. Finally, we identify key knowledge gaps and propose future research directions aimed at discovering reliable markers of mycorrhizal responses for epi-breeding and the development of climate-resilient agroecosystems.

Introduction: Rhino-orbital-cerebral mucormycosis (ROCM) is a rare, rapidly progressive, and fatal invasive fungal infection. This case series is the first to systematically characterize ROCM presenting primarily as cerebral infarction on imaging and highlights the value of metagenomic next-generation sequencing (mNGS) in the early diagnosis of such critical and atypical cases.

Main symptoms and important clinical findings: All seven patients had diabetes mellitus, with six concurrently presenting with ketoacidosis. Universal clinical features included fever and a fixed, dilated pupil. Most patients exhibited facial swelling (6/7, 85.7%) and visual impairment (5/7, 71.4%). Cerebral infarction was confirmed by head magnetic resonance imaging (MRI) in all individuals.

The main diagnoses therapeutic interventions and outcomes: The diagnosis was confirmed in all cases by the detection of Rhizopus species sequences via mNGS of cerebrospinal fluid (CSF). Six patients received treatment with amphotericin B cholesteryl sulfate complex, and two of these also underwent surgical debridement. Ultimately, only one patient survived, yielding a mortality rate of 85.7% (6/7).

Conclusion: ROCM should be highly suspected in diabetic patients presenting with acute cerebral infarction accompanied by fever and facial or ocular symptoms. mNGS enables rapid and early etiological diagnosis of ROCM, which is crucial for improving outcomes. Earlier diagnosis, combined antifungal therapy, and surgical intervention may be associated with better prognosis.

Background: The changing epidemiology of candidemia indicates a rise in non-albicans Candida species, especially resistant Candida auris and emerging Candida utilis. Although iron impacts fungal virulence, its role in these species remains poorly understood. This study investigates how manipulating iron levels influences biofilm formation, virulence enzymes, and antifungal susceptibility in clinical isolates.

Methods: A total of 216 isolates of Candida utilis, Candida albicans, and Candida auris from bloodstream infections over two years were identified via phenotypic methods, MALDI-TOF MS, VITEK 2, and 18S rRNA PCR. Susceptibility was tested using disc diffusion and broth microdilution with ferrous sulphate (FeSO₄). Virulence enzyme activities and biofilm formation were assessed under iron-rich and control conditions.

Results: Candida auris showed multidrug resistance, especially to fluconazole and caspofungin, with iron increasing caspofungin MICs up to 16-fold. Candida utilis exhibited strong biofilm formation and increased phospholipase and proteinase activities in the presence of FeSO₄, and also showed 4- to 32-fold increases in fluconazole resistance. Biofilm biomass was unaffected by iron, but enzyme activities varied by species and enzyme. Candida albicans had high proteinase and haemolysin activity but responded minimally to iron.

Conclusions: Iron differentially influences virulence-associated traits (biofilm-related enzyme activities) and antifungal resistance across these Candida species. C. utilis exhibits iron-responsive increases in phospholipase and proteinase activities together with amplified azole resistance, while C. auris shows iron-linked enhancement of echinocandin resistance and sustained expression of key virulence-associated enzymes. These results underscore the importance of accounting for host iron levels and species-specific responses when managing candidemia and indicate the potential for therapies targeting iron.

Background: Beauveria bassiana is an entomopathogenic fungus that can establish an intimate endophytic relationship with plants. Otherwise, microbial volatile organic compounds (VOCs) are important chemicals for plant recognition and interactions. Therefore, this study provides novel evidence of the biochemical and physiological responses of plants to VOCs emitted by B. bassiana and 3-methylbutanol (3MB) as the most abundant compound emitted by the fungus.

Methods: Sorghum plants were exposed to the standard 3MB and VOCs emitted by the fungal strains AS5 and AI2 of B. bassiana isolated from soil and a mycosed insect cadaver, respectively. The accumulation of reactive oxygen species (ROS) such as superoxide anion (O₂ ^•¯) and H₂O₂; quantification of phytohormones such as salicylic acid (SA), jasmonic acid (JA), and indole-3-acetic acid (IAA) and phenolic compounds in leaves (4-coumaric acid and flavonoids); and the expression of genes SbPR-1 and SbCOI1 related to the activation of SA- and JA-signaling defense pathways, respectively, were analyzed.

Results and discussion: VOCs emitted by B. bassiana and 3MB stimulate plant growth, likely by triggering the production of ROS and IAA. Furthermore, these fungal compounds increased the expression levels of SbPR-1 and SbCOI1 at 2 d and SbCOI1 at 7 d. Consistently, an increase in the content of SA, JA, and phenolic compounds was observed in the inoculated plants.

Conclusion: VOCs emitted by B. bassiana and 3-MB promote sorghum growth and activate adaptive defense traits. Moreover, VOCs from AS5 triggered a stronger biochemical response in plants than VOCs emitted by AI2. These results suggested that the response of the plant was strain-specific. Finally, 3MB is a fungal compound that may stimulate plant growth and defense.

The growing need for sustainable energy sources has led to the exploration of bioelectricity generation from microorganisms, with fungi showing considerable potential for powering small-scale robotic systems. Fungal bioelectricity stems from the ability of fungal mycelium to facilitate extracellular electron transfer, a process that can be exploited in microbial fuel cells (MFCs) for clean energy production. This field is gaining traction as fungi, with their extensive mycelial networks, offer unique conductive properties. These networks, providing a large surface area and excellent conductivity, make fungi well-suited for incorporation into fungal-based microbial fuel cells (FMFCs). Successful FMFC design and optimization require attention to critical factors such as electrode material, microbial interactions, and environmental conditions to enhance performance. Moreover, the use of fungi in small-scale robotic systems, forming biohybrid robots, holds significant promise for autonomous operations in applications like environmental monitoring and bio-inspired robotics. While fungal bioelectricity presents exciting opportunities, challenges such as energy efficiency, scalability, and integration persist. Nevertheless, ongoing research continues to advance the development of self-sustaining, environmentally friendly robotic systems powered by fungal bioelectricity, providing new avenues in renewable energy and robotics.

The diversity of marine fungi associated with macroalgae in Peru remains largely unknown, and no studies have provided holistic data on their biodiversity or their role as plant growth promoters in maize under salinity stress conditions. Endophytic and epiphytic fungi were isolated from the macroalgae Caulerpa sp., Ulva sp., Ahnfeltiopsis sp., and Chondracanthus chamissoi, collected from Yacila and Cangrejos beaches (Piura, Peru), while marine bacteria were provided by the Microbial Biotechnology Research Laboratory of the National University of Frontera. The growth-promoting properties of these marine microorganisms were evaluated prior to their inoculation in maize. Fungal isolates were phylogenetically characterized by ITS sequencing as Penicillium sp. YAFL13, Penicillium sp. YUFE7, Talaromyces stollii YAFL19, T. stollii YAFL4, T. amestolkiae YCFR3, Aspergillus sydowii CCDF2, A. sydowii YFep2, and A. sydowii YFep3. In total, 12 marine fungi were isolated and used in the assays along with 10 marine bacteria. Based on antimicrobial activity, IAA synthesis, siderophore production, phosphate solubilization, and hydrolytic enzyme production, three fungal strains (Penicillium sp. YAFL13, A. sydowii CCDF2, and A. sydowii YFep2) and two bacterial strains (Bacillus sp. YCFR5 and Pantoea agglomerans YAFL6) were selected. Among them, A. sydowii CCDF2 significantly enhanced maize growth parameters, highlighting its promising potential as a plant inoculant. This study represents one of the few reports on marine microorganisms associated with marine macroalgae, revealing a valuable fungal diversity and its potential role in promoting maize growth under saline stress conditions.

Fungi synthesize a wide variety of secondary metabolites (SMs). The genes of the biosynthetic pathways of many of these compounds are encoded by biosynthetic gene clusters (BGCs), which typically consist of a core biosynthetic enzyme, tailoring enzymes, transporters, and pathway-specific regulators. One of the well-studied fungal SMs is the polyketide terrein, which is produced by Aspergillus terreus and exhibits a wide range of biological activities, such as cytotoxic, phytotoxic, and antibacterial effects. The structure and function of the terrein BGC, the functions of the encoded proteins, and the processes controlling the transcriptional regulation of the BGC are summarized in this mini review. Both pathway-specific and global regulators and epigenetic regulation are presented. Furthermore, similar BGCs identified in other fungal taxa are introduced in short. Despite significant advances, key aspects of terrein biosynthesis, such as some protein functions, details of the BGC regulation, and SM ecological functions remain unresolved. Filling in these gaps will help us better understand the biology of fungal SMs and could pave the way for biotechnological applications.

Trichoderma spp. are the most widely used fungal species in biofertilizers due to their capacity to enhance soil quality, suppress plant pathogens, and promote plant growth. However, due to the popularity of Trichoderma spp., usages in agricultural systems have raised significant environmental and safety concerns. This review mainly emphasizes the mechanisms that underlie the ecological dominance and competitive nature of Trichoderma spp. over native microbial communities and then explores the multifunctional role of Trichoderma spp. in soil ecosystems, which mainly focus on its interactions within the rhizosphere that influence dynamics plant-microbe interactions and nutrient cycling. This article also highlights potential ecological imbalances associated with prolonged or repeated applications of Trichoderma spp. which include changes in soil microbial biodiversity and the decline of beneficial native microbiota. Furthermore, it evaluates the safety issues of Trichoderma-based biofertilizers by focusing their bioactive metabolites and potential effects on humans, animals, and non-target living things. Therefore, the review addresses the importance of site-specific application strategies, monitoring protocols, and comprehensive ecotoxicological assessments to mitigate unintended environmental and health concerns. By synthesizing recent findings and identifying key knowledge gaps, this work provides a framework for the responsible and sustainable integration of Trichoderma spp. into modern agroecological systems.

Introduction: Candidiasis, an opportunistic fungal infection, is increasingly caused by non-albicans Candida species that show reduced fluconazole susceptibility, mainly due to ERG11 overexpression. This study aimed to identify Candida species, determine fluconazole resistance using VITEK 2 and disc diffusion methods, and detect ERG11 gene mutations in Candida tropicalis.

Methodology: A total of 410 clinical samples were included in this laboratory-based prospective study conducted at a tertiary care hospital in Mysuru. Fluconazole-resistant Candida species were identified using the Vitek-2 system and disc diffusion methods. The ERG11 gene of fluconazole-resistant strains of Candida tropicalis was amplified by polymerase chain reaction (PCR) and subjected to high-resolution melt (HRM) analysis to detect A395T and C461T mutations.

Results: A total of 410 Candida species were isolated from 410 clinical isolates during the study period, with 61% (250/410) from males and 39% (160/410) from females. Among the 410 isolates tested by Vitek-2, 29 (7.07%) were resistant to fluconazole, with the majority being C. tropicalis (51.7%). Of the 15 C. tropicalis isolates tested, A395T and C461T mutations in the ERG11 gene were detected in 6 isolates. These isolates showed high minimum inhibitory concentrations (MICs) to azoles. Discrepancies between Vitek-2 and PCR findings likely reflect the multifactorial nature of fluconazole resistance and the presence of resistance mechanisms beyond the targeted ERG11 mutations.

Conclusion: The study concludes that antifungal susceptibility testing (AST) using Vitek-2 is a preferred method in the laboratory for identifying Candida species and performing susceptibility testing due to its ease of use and cost-effectiveness. Disc diffusion can be utilized in resource-limited settings to guide treatment, while PCR and newer molecular methods offer valuable opportunities for researching different mechanisms and mutations responsible for fluconazole resistance, a widely used antifungal for treatment and prevention.