Journal of Fungi

Ustilago esculenta is a dimorphic fungus that specifically infects Zizania latifolia, causing stem swelling and the formation of an edible fleshy stem known as jiaobai. The pathogenicity of U. esculenta is closely associated with the development of jiaobai and phenotypic differentiation. Msb2 acts as a key upstream sensor in the MAPK (mitogen-activated protein kinase) signaling pathway, playing critical roles in fungal hyphal growth, osmotic regulation, maintenance of cell wall integrity, temperature adaptation, and pathogenicity. In this study, we cloned the UeMsb2 gene from U. esculenta (GenBank No. MW768949). The open reading frame of UeMsb2 is 3015 bp in length, lacks introns, encodes a 1004-amino-acid protein with a conserved serine-rich domain, and is localized to the vacuole. Expression analysis revealed that UeMsb2 is inducibly expressed during both hyphal growth and infection processes. Deletion of UeMsb2 did not affect haploid morphology or growth rate in vitro but significantly impaired the strain’s mating ability, suppressed filamentous growth, slowed host infection progression, and downregulated the expression of b signaling pathway genes associated with pathogenicity. Notably, the deletion of UeMsb2 did not influence the in vitro growth of U. esculenta under hyperosmotic, thermal, or oxidative stress conditions. These findings underscore the critical role of UeMsb2 in regulating the pathogenicity of U. esculenta. This study provides insights into the interaction between U. esculenta and Z. latifolia, particularly the mechanisms that drive host stem swelling. Full article

Boletaceae, the largest and most diverse family of Boletales (Agaricomycetes and Basidiomycota), is both ecologically and economically important. Although many taxa have been described in China, the diversity of the family still remains incompletely understood. In the present study, Pseudophylloporus baishanzuensis gen. nov., sp. nov. and Rubroleccinum latisporus gen. nov., sp. nov. are proposed based on morphological and molecular phylogenetic analyses. These findings contribute to a deeper understanding of the diversity within the Boletaceae family. Full article

Nakaseomyces glabrata (Candida glabrata), the second most prevalent Candida pathogen globally, has emerged as a major clinical threat due to its ability to develop high-level azole resistance. In this study, two new 5,6-dihydrotetrazolo[1,5-c]quinazoline derivatives (c11 and c12) were synthesized and characterized using IR, LC-MS, ¹H, and ¹³C NMR spectra. Along with 13 previously reported analogues, these compounds underwent in vitro antifungal testing against clinical N. glabrata isolates using a serial dilution method (0.125–64 mg/L). Remarkably, compounds c5 and c1 exhibited potent antifungal activity, with minimum inhibitory concentrations of 0.37 μM and 0.47 μM, respectively—about a 20-fold improvement in μM concentration over standard drugs like amphotericin B, caspofungin, and micafungin. A detailed structure–activity relationship analysis revealed crucial molecular features enhancing antifungal potency. Extensive molecular docking studies across 18 protein targets explored potential binding pockets and affinities of the lead compounds. A robust 3D-QSAR model, incorporating molecular descriptors Mor26m and Mor29e, displayed good predictive ability for antifungal activity. In silico predictions indicated an absence of herbicidal effect, negligible environmental toxicity (to honeybees, avian species, and aquatic organisms), and mild human toxicity concerns for these compounds. This comprehensive approach aims to develop novel and effective antifungal compounds against the clinically relevant pathogen N. glabrata. Full article

Monascinol (Msol), an analog of monascin (MS) produced by Monascus pilosus, possesses potential anti-inflammatory properties. This study compares the effects of M. pilosus SWM-008 fermented red mold rice, which contains the functional components MS and Msol, on liver and kidney damage related to diabetic complications in rats. An animal model of liver and kidney injury was induced by an intraperitoneal injection of streptozotocin (STZ) at 65 mg/kg body weight combined with nicotinamide (NA) at 150 mg/kg body weight. Our findings indicate that Msol significantly reduces STZ-NA induced pro-inflammatory markers, including interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) in both liver and kidney tissues. Significant improvements were noted in the histopathological assessments. Msol was more effective than MS in suppressing renal IL-1β and COX-2 expressions. In summary, the findings indicate that Msol shows potential as a novel therapeutic agent for treating liver and kidney injuries associated with diabetic complications. Full article

Batkoa is a genus of entomophthoralean fungi often associated with insect epizootics, particularly in phytophagous hemipterans. Encapsulation has become a promising strategy for improving the shelf life and sporulation of these fungi post-application. This study aims to (i) compare the virulence of the submerged propagules and primary conidia of Batkoa sp. ESALQ1199 against Dalbulus maidis; (ii) formulate submerged propagules in calcium alginate beads with co-formulants; (iii) assess the colony-forming units and sporulation of encapsulated beads dried with different kaolin concentrations (0%, 2%, 4%, 8% and 10%); (iv) determine the shelf life of dried bead formulations containing 10% kaolin, comparing washed and unwashed beads treated with a 4% sucrose solution; and (v) assess the sporulation capacity of beads with 10% kaolin, washed and unwashed with 4% sucrose solution, over time under humid conditions. Our results demonstrated that primary conidia and submerged propagules effectively killed 82.4% and 57.8% of adult corn leafhoppers, respectively. Co-formulants maintained viability above 80% in dried propagules, while control samples dropped to 45%, indicating the sensitivity of submerged propagules to the drying process. Encapsulated Batkoa sp. retained the same concentration of viable propagules per bead and the number of conidia produced (sporulation) for 30 days at 28 °C. The sporulation of fresh beads increased during the incubation period, plateauing after 27 days. This suggests that Batkoa sp. beads can produce primary conidia under humid field conditions, serving as a potential inoculum source for new infections. Full article

As environmental and health concerns increase, the trend toward sustainable agriculture is moving toward using biological agents. About 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species in these products. However, the name T. harzianum has often been used incorrectly in culture collections, databases, and scientific literature due to the division of the Harzianum clade (HC) into more than 95 cryptic species, with only one being named T. harzianum. In this study, 49 strains previously identified as T. harzianum in three surveys of Trichoderma species from soils in South and Central America were re-identified using phylogenetic analyses based on tef1α, rpb2, and ITS sequences obtained from GenBank. These were combined with the HC species from two other studies, which were identified based on the current taxonomy. Based on the results of the five surveys of the total 148 strains in HC, 11 species were identified. T. afroharzianum, T. lentiforme, and T. endophyticum, followed by T. azevedoi and T. harzianum, were the dominant species of the HC in South and Central America. This is the first report to identify dominant Trichoderma species within the HC in South and Central American soil based on multiple studies. These results will be useful in selecting strains within the clade for the formulation of biocontrol and biofertilizer products on the continent. Full article

Pythiosis, a rare and formidable infectious disease caused by Pythium insidiosum, is characterized by profound uncertainties in achieving definitive diagnoses, suboptimal outcomes, and an exceptionally high mortality rate. Here, we present a rare case of human spinal pythiosis in southern China. With advanced metagenomic sequencing technology, Pythium insidiosum was pinpointed as the causative pathogen. We discovered that the inoculation of either tissue fragments or homogenate yielded more successful results and enabled a moderate extension of the culture duration to 5–10 days through an exhaustive comparison of diverse inoculation and culture conditions for general clinical specimens. A pronounced genetic affinity of the isolated strain towards the Pythium insidiosum strain MCC 13 was detected after a comprehensive whole-genome sequencing analysis. Antifungal agents exhibited negligible sensitivity towards Pythium insidiosum in an antimicrobial susceptibility test. Conversely, antibacterial agents such as oxazolidinones, tetracyclines, macrolides, and amphenicols demonstrated varying degrees of sensitivity, albeit with most of their minimum inhibitory concentrations (MICs) substantially surpassing the safe concentration ranges for effective clinical treatment. Notably, tigecycline stood out as a promising candidate, exhibiting favorable therapeutic effects at moderate concentrations, making it a potential drug of choice for the control of pythiosis. A combined susceptibility test suggested that combinations of tetracyclines with macrolides, oxazolidinones, and amphenicols exhibited synergistic antibacterial effects, with the combination of doxycycline and trimethoprim–sulfamethoxazole (TMP-SMX) in particular playing a pivotal role. To our surprise, the MICs of iron chelators, specifically deferiprone and deferoxamine, against the strain were exceedingly low, which led to the speculation that exogenous iron chelators may have competitively inhibited the iron-chelating enzymes of the strain. The research derived from this single, rare case has certain limitations, but considering that there are currently no reports of invasive infections of deep organs in humans caused by Pythium insidiosum, the above findings can offer novel insights into the treatment of invasive pythiosis. Combination therapy based on tetracyclines, especially tigecycline, the use of TMP-SMX, and the adjunctive use of iron chelators, represent promising approaches to tackle the clinical challenges in the treatment of invasive pythiosis. However, further studies, including similar cases of spinal pythiosis and in vivo trials, are still needed to validate them. In addition, while paying attention to the therapeutic potentials of the above plans, we should also closely monitor the risks and side effects that may arise from excessive MICs or the expanded use of related drugs during the treatment process. Full article

The global rise in population has led to an increased demand for food production, necessitating the adoption of sustainable agricultural practices. Traditional methods often rely on synthetic chemicals that negatively impact both human health and the environment. This study aimed to screen soil fungal strains for plant-growth-promoting traits, specifically focusing on their ability to solubilize phosphates, produce indole-3-acetic acid (IAA), and synthesize siderophores. Fungal strains were identified using rDNA sequencing of the ITS regions, and their growth-promoting abilities were assessed in vitro. Aspergillus flavus JKJ7, Talaromyces purpureogenus JKJ12, and Trichoderma koningiopsis JKJ18 exhibited varying degrees of phosphate solubilization, with T. purpureogenus JKJ12 solubilizing the highest amount of tricalcium phosphate (TCP), while A. flavus JKJ7 was the most effective in solubilizing phytic acid calcium salt (PCS). In terms of IAA production, A. flavus JKJ7 produced the highest auxin concentration (68.51 mg/L), followed by T. koningiopsis JKJ18 and T. purpureogenus JKJ12. Additionally, A. flavus JKJ7 produced the highest amount of siderophores (83.7%), indicating its potential for improving iron uptake in plants. Principal Component Analysis (PCA) revealed distinct functional capabilities among the strains, particularly in phosphate solubilization and IAA production, suggesting their complementary use in consortium formulations. These results indicate that these fungal strains possess significant plant-growth-promoting traits and could be used as bioinoculants for sustainable agriculture, either as single strains or in combination Full article

The present study reports the ability of a fungal isolate Aspergillus ochraceus DY1, obtained from rotten wood, to degrade alkali lignin (AL) and lignocelluloses in an efficient manner. The efficiency of degradation was monitored by measuring the percentage of decolorization and utilizing GC-MS for identifying degradation products at different time intervals (10, 20, 30, and 40 days). The optimal degradation of alkali lignin (AL) was achieved at 0.01% concentration, 25 °C, and pH 7, resulting in 63.64% degradation after 40 days of incubation. A GC-MS analysis revealed significant degradation products, including n-hexadecanoic acid, octadecane, butylated hydroxytoluene, 2,6,11-trimethyl-dodecane, dibutyl phthalate, oleic acid, 3,5-dimethoxy-phenol acetate, and 2-(phenylmethylene)- cyclohexanone. Structural changes in AL were confirmed through HSQC 2D NMR and size-exclusion chromatography, indicating depolymerization and reduced molecular weight. Furthermore, A. ochraceus DY1 demonstrated substantial biomass loss in corn stover (62.5%) and sugarcane bagasse (50%) after 7 days of solid-state fermentation. Surface morphological depletion was observed in the bio-treated corn stover through SEM and confocal microscopy, which was not seen in the untreated one. These findings underscore the potential of A. ochraceus DY1 for efficient lignin degradation, with promising applications in biofuel production, waste management in the paper and pulp industry, and the synthesis of value-added bioproducts. Full article

In this paper, we present a novel class of hybrid polyketides, tenuazamines A–H (1–8), which exhibit a unique tautomeric equilibrium from Alternaria alternata FL7. The elucidation of the structures was achieved through a diverse combination of NMR, HR-ESIMS, and ECD methods, with a focus on extensive spectroscopic data analysis. Notably, compounds 1, 4, 8–9 exhibited potent toxic effects on the growth of Arabidopsis thaliana. This research expands the structural diversity of tenuazonic acid compounds derived from endophytic fungi and provides potential hit compounds for the development of herbicides. Full article

In the industrial production of Lentinula edodes and Pleurotus eryngii, slow growth of the mother seed and insufficient hyphal vitality can significantly affect the cultivation process. To shorten the growth period on traditional PDA medium, two strains of L. edodes and P. eryngii were cultured with different proportions of P. tuber-regium and Wolfiporia hoelen sclerotium powders added into the medium to investigate the effect on the mycelial growth. Compared to the PDA, the addition of sclerotia powder significantly enhanced the growth of mycelia, with an optimal addition ratio of 2%. Transcriptome sequencing was performed after culturing L. edodes and P. eryngii on PDA, PDA with 2% P. tuber-regium sclerotium powder, and PDA with 2% W. hoelen sclerotium powder. GO enrichment analysis of the differentially expressed genes (DEGs) of L. edodes and P. eryngii strains cultured in the sclerotia powder media showed significant changes in oxidoreductase and glucosidase activities. Changes were observed in KEGG annotation for carbohydrate metabolism, glycolysis, pyruvate metabolism, and other energy metabolic pathways. Moreover, carbohydrate-active enzyme (CAZyme) family genes were predominantly upregulated. The increase in the activity of CAZyme and oxidoreductases promotes the degradation of nutrients in the sclerotia into small-molecule substances, which explains why the sclerotia powder culture medium promotes mycelial growth. Full article

The complex structure of the plant cell wall makes it difficult to use the biomass produced by biosynthesis. For this reason, the search for new strains of microorganisms capable of efficiently degrading fiber is a topic of interest. For these reasons, the present study aimed to evaluate both the microbiological and enzymatic characteristics of the fungus Curvularia kusanoi L7strain. For this, its growth in different culture media was evaluated. Wheat straw mineralization was evaluated by gas chromatography assisted by infrared spectroscopy. The production of endo- and exoglucanase, laccase, and peroxidase enzymes in submerged solid fermentation of wheat and sugarcane bagasse were characterized. The strain efficiently mineralized raw wheat straw, showing a significant decrease in signals associated with cellulose, hemicellulose, and lignin in the infrared spectra. High enzyme productions were achieved in submerged solid fermentation of both substrates, highlighting the high production of endoglucanases in sugarcane bagasse (2.87 IU/mL) and laccases in wheat (1.64 IU/mL). It is concluded that C. kusanoi L7 is an ascomycete with a versatile enzyme production that allows it to exhaustively degrade complex fibers such as raw wheat straw and sugar cane bagasse, making it a microorganism with great potential in the bioconversion of plant biomass. Full article

Citrus spp. represent an economically important fruit tree crop worldwide. However, molecular mechanisms underlying the interaction between citrus and the Colletotrichum gloeosporioides remain largely unexplored. In this study, we analyzed the physiological and transcriptomic changes in Citrus sinensis at different stages of incubation with C. gloeosporioides. The results indicated that C. gloeosporioides infection rapidly triggered necrosis in the epicarp of C. sinensis fruits, decreased the total flavonoid contents, and suppressed the activity of catalase, peroxidase, and superoxide dismutase enzymes. Upon inoculation with C. gloeosporioides, there were 4600 differentially expressed genes (DEGs) with 1754 down-regulated and 2846 up-regulated after six hours, while there were only 580 DEGs with 185 down-regulated and 395 up-regulated between six and twelve-hours post-inoculation. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the DEGs, which exhibited consistent up-regulation, were associated with metabolic processes and stress responses. Through Weighted Gene Co-Expression Network Analysis, 11 key genes have been identified that could potentially play a role in the transcriptional regulation of this process, including the transcription factor bHLH189. Furthermore, the infection of C. gloeosporioides had a notable effect on both the flavonoid metabolism and the metabolic pathways related to reactive oxygen species. Our findings help to understand the interaction between citrus and C. gloeosporioides and unveil how new insights into how C. gloeosporioides circumvents citrus defense mechanisms. Full article

Fusarium oxysporum, the pathogen responsible for apple replant disease (ARD), is seriously threatening the apple industry globally. We investigated the antagonistic properties of Trichoderma strains against F. oxysporum HS2, aiming to find a biological control solution to minimize the dependence on chemical pesticides. Two of the thirty-one Trichoderma strains assessed through plate confrontation assays, L7 (Trichoderma atroviride) and M19 (T. longibrachiatum), markedly inhibited = F. oxysporum, with inhibition rates of 86.02% and 86.72%, respectively. Applying 1 × 10⁶ spores/mL suspensions of these strains notably increased the disease resistance in embryonic mung bean roots. Strains L7 and M19 substantially protected Malus robusta Rehd apple rootstock from ARD; the plant height, stem diameter, leaf number, chlorophyll content, and defense enzyme activity were higher in the treated plants than in the controls in both greenhouse and field trials. The results of fluorescent labeling confirmed the effective colonization of these strains of the root soil, with the number of spores stabilizing over time. At 56 days after inoculation, the M19 and L7 spore counts in various soils confirmed their persistence. These results underscore the biocontrol potential of L7 and M19 against HS2, offering valuable insights into developing sustainable ARD management practices. Full article

Diaporthe (anamorph: Phomopsis) species are endophytes or fungal pathogens for many different plant species. Soybean (Glycine max) can be infected by many different Diaporthe species; among them, D. caulivora and D. longicolla are responsible for the most significant damages. Diaporthe goulteri is a species that was only recently described and has so far been found on sunflower (Helianthus annuus) in Australia and an unknown host in Thailand. Here, we report isolation of D. goulteri from soybean in southern Germany, molecular species identification, and additional morphological description. We also show that D. goulteri can infect soybean and describe the symptoms we observed, both on the plant where the isolate came from and following artificial inoculation. Full article

Frogeye leaf spot on soybeans is traditionally considered as a southern disease in the United States but its impact in North Central USA has been rising in recent years. In this study, we investigated the population structure and mating type distribution in the C. sojina population from Indiana, USA. Based on 27 single nucleotide polymorphism markers, 49 multi-locus genotypes (MLGs) were identified in 234 isolates collected from 29 counties in Indiana in 2020. Bayesian analysis grouped the 49 MLGs into three clusters. This grouping was supported by principal coordinate analysis and, in large part, by the unweighted pair group method with arithmetic mean and minimal spanning tree. Only one mating-type idiomorph was found in each isolate and in each MLG. The MAT1-1 idiomorph was found in 22 MLGs and the MAT1-2 idiomorph was found in 27 MLGs. Based on clone-corrected data, the distribution of mating-type idiomorphs did not deviate significantly from 1:1 ratio in Indiana as a whole and in 22 out of 24 counties where two or more MLGs were found. Thirty MLGs contained QoI-resistant isolates and 22 MLGs contained QoI-sensitive isolates, with three MLGs containing both types of isolates. MLG1, the most common MLG with 90 isolates, contained mostly QoI-resistant isolates. Interestingly, MLG1 was also the dominant genotype in the Tennessee population collected in 2015, suggesting that MLG1 has been a dominant genotype in a wider region for many years. Based on the standard index of association ($\overline{r}$_d), the Indiana population as a whole was in significant linkage disequilibrium. However, in five out of 16 counties where three or more MLGs were found, the null hypothesis of linkage equilibrium was not rejected. Tests of linkage disequilibrium between locus pairs showed that 33.3% of locus pairs on the same contigs were in significant disequilibrium and 17.7% of locus pairs on different contigs were in significant disequilibrium. The possibility of a cryptic sexual stage was discussed. Full article

Black spot, one of the major diseases of kiwifruit, is caused by Alternaria alternata. A comprehensive investigation into its pathogenicity mechanism is imperative in order to propose a targeted and effective control strategy. The effect of L-arginine on the pathogenicity of A. alternata and the underlying mechanisms were investigated. The results showed that treatment with 5 mM L⁻¹ of L-arginine promoted spore germination and increased the colony diameter and lesion diameter of A. alternata in vivo and in vitro, which were 23.1% and 9.3% higher than that of the control, respectively. Exogenous L-arginine treatment also induced endogenous L-arginine and nitric oxide (NO) accumulation by activating nitric oxide synthase (NOS), arginine decarboxylase (ADC) and ornithine decarboxylase (ODC). In addition, exogenous L-arginine triggered an increase in reactive oxygen species (ROS) levels by activating the activity and inducing gene expression upregulation of NADPH oxidase. The hydrogen peroxide (H₂O₂) and superoxide anion (O₂^.−) levels were 15.9% and 2.2 times higher, respectively, than in the control group on the second day of L-arginine treatment. Meanwhile, antioxidant enzyme activities and gene expression levels were enhanced, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR). In addition, exogenous L-arginine stimulated cell wall-degrading enzymes in vivo and in vitro by activating gene expression. These results suggested that exogenous L-arginine promoted the pathogenicity of A. alternata by inducing the accumulation of polyamines, NO, and ROS, and by activating systems of antioxidants and cell wall-degrading enzymes. The present study not only revealed the mechanism by which low concentrations of L-arginine increase the pathogenicity of A. alternata, but also provided a theoretical basis for the exclusive and precise targeting of A. alternata in kiwifruit. Full article

Truffles are valuable underground mushrooms with significant economic importance. In recent years, their cultivation has achieved satisfactory results, but not for all species. The harvesting of white truffles (Tuber magnatum Picco) is still dependent on natural production, which is at risk due to various issues, such as improper forest management. A useful practice to protect natural resources is to promote the expansion of productive forests. In this study, we investigate the dynamics of the microbiome in an old and new truffle forest using an amplicon sequencing approach of the fungal ITS region and the prokaryotic 16S rRNA gene. We monitor the soil biological community’s development to compare differences and similarities between the primary productive forest and the expanding area over a two-year sampling period. In particular, we observed the colonization of vacant ecological niches by certain fungi, such as those belonging to the genus Mortierella. Additionally, we examined the competitive interactions between saprotrophs and ectomycorrhizal fungi (ECM). In both study areas, the bacterial community was dominated by Pseudomonadota, Planctomycetota, and Actinomycetota. The behavior of the Tuber genus differed significantly from other ECMs and displayed positive correlations with bacterial taxa such as Ktedonobacter, Zavarzinella, and Sphingomonas. The present work provides an initial overview of expanding white truffle habitats. Further, more specific research is needed to explore potential connections between individual taxa. Full article