Trichoderma is a diverse genus in the family Hypocreaceae (Hypocreales) with significant ecological roles in forest ecosystem. They contribute to nutrient cycling through decomposition of organic matter and enhance plant growth. Owing to this importance, the morphological, molecular, and enzymatic characteristics of Trichoderma species have been extensively studied worldwide. Approximately, 495 species have been reported worldwide, whereas only 50 species have been recorded in Korea. To narrow this gap, 11 Trichoderma strains were isolated from soil samples collected from fir and deciduous forests in 2013 and 2017. Morphological observations and multi-marker phylogenetic analyses were subsequently conducted using the second largest subunit of RNA polymerase II (rpb2) and translation elongation factor 1-alpha (tef1) regions. Among the strains, four unrecorded Trichoderma species in Korea were identified: T. chlamydosporum, T. concentricum, T. hirsutum, and T. italicum. This study expands the known diversity of Trichoderma in Korea and provides detailed cultural characteristics and phylogenetic relationships of these four unrecorded species.

Penicillium crustosum and Penicillium solitum are common molds known for their ability to thrive at cool temperatures and low water activities. They are frequently associated with the contamination of cheeses, pome fruits, and meats. While many strains of these species are recognized for producing bioactive metabolites, their volatile metabolism remains poorly understood. In this study, a comprehensive gas chromatography–mass spectrometry (GC–MS) was employed to identify and analyze the volatile organic compounds (VOCs) emitted by P. crustosum strain G10 and P. solitum SA. When cultivated on laboratory media, a total of 25 distinct VOCs were identified from P. crustosum G10, and 17 from P. solitum SA. The VOCs produced by G10 were classified into six categories based on their functional groups: alcohols (four compounds), nitriles (three compounds), alkenes (four compounds), ketones (two compounds), esters (five compounds), and alkanes (three compounds). Notably, several of these VOCs have known biological activities. For instance, 2-tetradecanol and benzyl nitrile have been developed as environmentally safe pest control agents; (E)-5-eicosene exhibits anticancer function; and 4-acetylphenoxyacetic acid shows potential for the inhibition of HIV. Additionally, (Z)-7-hexadecene, octadecanal, and 5-dodecyldihydro-2(3H)-furanone are recognized as insect volatile pheromones. The VOCs from P. solitum SA were grouped into four main categories: alcoholic compounds (two VOCs), aromatic compounds (four VOCs), esters (three VOCs), and alkene compounds (three VOCs). The discussion of these compounds’ potential applications offers new perspectives on their future utilization.

This paper documents 17 newly recorded species belonging to the orders Eurotiales, Hypocreales, Pleosporales, Venturiales, and Wallemiales. These species were obtained from freshwater, brackish water, and soil habitats and identified using phenotypic techniques combined with DNA sequence data. Two species belonged to the order Eurotiales (Talaromyces calidominioluteus, and T. endophyticus); two species belonged to the order Hypocreales (Parasarocladium wereldwijsianum, and Simplicillium lamellicola); 11 species belonged to the order Pleosporales (Allophoma tropica, Alternaria longxiensis, Anteaglonium parvulum, Camarosporomyces flavigenus, Edenia achyranthi, Hongkongmyces thailandicus, Periconia imperatae, Pseudopithomyces pavgii, Septoriella huberti, Spegazzinia tessarthra, and Torula chiangmaiensis); one species belonged to the order Venturiales (Scolecobasidium terrestre); and one species belonged to the order Wallemiales (Wallemia mellicola). Detailed descriptions, illustrations, and phylogenetic analysis results of these species have been provided.

Komatsuna (Brassica rapa var. perviridis) is one of the most common leafy vegetables in Japan. In recent years, the frequent occurrence of abnormally high temperatures is becoming a threat for komatsuna as it is vulnerable to high temperature stress. In natural ecosystems, most plants coexist with endophytic fungi as a strategy to adapt to stressful environments. Among known symbiotic fungi, there are dark septate endophytes (DSEs), which are unique due to their prevalence under stressed environmental conditions. This study aimed to evaluate the use of DSEs to improve komatsuna growth using a greenhouse farming system, as a practice to improve sustainable agriculture. We examined the effect of inoculation with three DSE isolates: Phialocephala fortinii KS.F.6 (Pf), Exophiala pisciphila KS.F.3.4 (Ep) and Veronaeopsis simplex Y34 (Vs), on the growth of komatsuna under high temperature stress. The preliminary experiment showed that inoculation with isolates Ep and Vs reduced the heat injury index and increased the number of surviving plants under 35 °C heat stress. Furthermore, the greenhouse experiment showed that Ep and Vs increase the number of leaves, fresh weight, and dry weight of komatsuna. This is considered the first report of DSE symbiosis potential for komatsuna high-temperature-stress mitigation and growth performance induction.

Helix-loop-helix (HLH) transcription factors are essential regulators of various cellular processes, including growth, differentiation, and development. In Aspergillus fumigatus, a major fungal pathogen, the HLH transcription factor encoded by the AfudrnA gene plays a critical role in the organism’s asexual reproductive cycle. This study provides a comprehensive analysis of AfudrnA and its function in conidiation, a key asexual reproductive process. Through targeted deletion of AfudrnA, we observed a dramatic reduction in conidia production, leading to an aconidial phenotype, which suggests that AfudrnA is indispensable for conidiation in A. fumigatus. The deletion mutants, however, showed no significant changes in growth rate or sensitivity to antifungal agents, indicating that AfudrnA specifically influences conidiation rather than general growth or stress responses. To confirm the role of AfudrnA, we reintroduced the gene into the deletion mutants, which restored normal conidiation, further underscoring its essential role in the process. Moreover, expression analysis revealed that AfudrnA is highly expressed during the early stages of conidiation, with transcript levels peaking 6 h after induction of asexual development. Interestingly, the deletion of AfudrnA also led to a significant downregulation of brlA, a key regulator of conidiation, highlighting a potential regulatory interaction between these two factors. These findings elucidate the critical role of AfudrnA in the conidiation of A. fumigatus and contribute to our understanding of the molecular mechanisms governing asexual reproduction in filamentous fungi. This study not only enhances our knowledge of fungal biology but also provides potential targets for therapeutic intervention against fungal pathogens.

Macrofungi play vital roles in forest ecosystems as decomposers, mycorrhizal symbionts, pathogens, and bioindicators of biodiversity. However, research on macrofungal diversity remains limited, particularly in ecologically preserved regions where long-term monitoring is crucial. Kyodong Island, located near the Military Demarcation Line in the Republic of Korea, has remained relatively isolated, making it a valuable site for studying fungal biodiversity. This study aimed to assess the macrofungal diversity of Kyodong Island, marking the first large-scale and comprehensive fungal survey. Between March and September 2024, 226 fungal specimens were collected and identified into 99 species based on morphological and molecular analyses. Six previously unrecorded species from Korea were confirmed in this study: Hypoxylon ticinense from the Ascomycota and five species from Basidiomycota (Amanita subovalispora, Collybiopsis hirtella, Hohenbuehelia grisea, Pseudosperma yunnanense, and Russula pseudojaponica). The results revealed a high diversity of saprotrophic fungi (79.8%) followed by ectomycorrhizal (19.19%) and parasitic (1.01%) species, with dominant genera including Amanita and Collybiopsis. Notably, the presence of fungal species previously documented in tropical climates suggests a possible northward shift in fungal distribution, likely influenced by climate change. These findings highlight the ecological importance of Kyodong Island as a reservoir of fungal diversity and emphasize the necessity of continued biodiversity monitoring. Future research should focus on long-term ecological monitoring, the effects of climate change and human impact on fungal distribution, and the functional roles of newly recorded species in sustaining forest ecosystems.

This study aimed to establish a fungal symbiont culture collection for coastal dune conservation and determine the diversity and distribution of endophytic fungi in rocky coastal dunes at Gimnyeong and Woljeong in the Jeju Islands. Endophytic fungi can promote plant growth and induce systemic resistance to environmental stress and infections in host plants. The native plant species thriving in these habitats play a crucial role in preventing coastal erosion. A total of 138 fungal endophytes were isolated from two plant groups: basalt-dwelling lithophytes (83 isolates) and sandy soil-dwelling halophytes (55 isolates). The host plants belonged to nine orders, 11 families, 14 genera, and 14 species. Molecular identification and phylogenetic analysis based on internal transcribed spacer (ITS) regions classified the isolates into six fungal classes, 11 orders, 15 families, and 22 genera. The dominant classes were Sordariomycetes (51.45%), Eurotiomycetes (26.09%), Dothideomycetes (18.84%). The dominant genera were Penicillium (33.58%), Fusarium (16.79%), Aspergillus (15.33%), and Talaromyces (10.22%). Endophyte diversity, as measured by Shannon’s diversity index (2.131), was higher in basalt-habitat lithophytes than in sandy soil-dwelling halophytes. However, no distinct pattern was observed in the variation of endophyte diversity or richness across plant life cycles (annual, perennial, or biennial species).

Pine wilt disease caused by pine wood nematodes (PWN) have been reported to give severe damage in many countries worldwide. Many measures of PWN management have been implemented, including using the nematophagous fungus Esteya vermicola as a biological control agent. However, understanding on the interaction between this fungus and pine trees is still limited. This study aimed to evaluate the effects of resinous compounds on spore germination and mycelial growth of E. vermicola in vitro. Research results showed that resinous compounds from pine trees significantly affect spore germination and mycelial growth of E. vermicola. In which, (+)α-pinene, (-)α-pinene, and (-)limonene completely inhibited spore germination and mycelial growth, with 100% of spore germination inhibition rate (SGIR) and mycelial growth inhibition rate (MGIR). The mixture of 14 resinous compounds also indicated potent inhibition of spore germination and mycelial growth of E. vermicola, with 100% and 91.8% SGIR and MGIR, respectively. These results suggest that trunk injection of spore suspension of E. vermicola to pine tree could be unsuccessful and ineffective for the control of pine wilt disease.

The plant pathogenic fungus Ascochyta rabiei produces solanapyrones, which are polyketide-derived secondary metabolites, during its saprobic growth on straws. Previously, we utilized A. rabiei as a heterologous host to produce a lichen-derived polyketide with anticancer activities. This study aimed to establish A. rabiei as a sustainable biorefinery for production of biologically active compounds through two objectives: optimizing culture conditions on agricultural waste substrates for polyketide production and generating a clean host using the Cre-loxP system for reusable antibiotic resistance markers. We found that soy hull is the most effective substrate among lignocellulosic materials. Neither light nor the addition of extra divalent cations were required for solanapyrone production in A. rabiei. Production of solanapyrones peaked 18 days after culture on soy hull pellets. To generate a clean host, we deleted the pks1 gene, involved in melanin biosynthesis, and the sol1 gene, responsible for solanapyrone production. Antibiotic resistance markers used in genetic transformation were recycled by establishing a Cre-loxP system in A. rabiei. In this system, Cre recombinase was expressed under the control of a promoter inducible during sporulation to mitigate the cytotoxicity of Cre. Here, we set the groundwork for developing A. rabiei as an environmentally-friendly biorefinery by generating a clean host with a Cre-loxP marker recycling system and optimizing growth conditions with soy hull pellets.

Edible mushroom cultivation often involves sterilizing the substrate, or a similar heat process like pasteurization, to facilitate mycelial colonization. Chemical treatments are an alternative approach that is also employed in some regions. Mycelial growth and density were analyzed in vitro by capturing daily photographs using a digital camera, with sterilized substrate serving as the control treatment. Our findings revealed that both fermented and sterilized substrates had similar growth patterns, although fermented treatment required a longer incubation time for full substrate colonization. Mycelium in fermented substrate had a denser structure compared to sterilized treatment, reflecting the interactions with the naturally-present microorganisms within the substrate. Conversely, mycelium in sterilized treatment exhibited faster substrate colonization times but had a less dense mycelial structure. Yeast and bacterial colonies were present throughout the fermentation process and 7 days after P. ostreatus mycelium inoculation, indicating active microbial communities during colonization. An initial decrease in CFU on the 3rd day, followed by an increase by the 7th day, suggests a shift toward anaerobic and facultative microorganisms due to oxygen depletion during fermentation. Mold colonies disappeared by the end of fermentation. Despite the complex interactions between yeast, bacteria, and P. ostreatus mycelium, the naturally-present microorganisms in the substrate appear to have at least neutral effects, enabling mycelial growth.