Mycobiology最新文献

A novel fungal strain, designated KNUF-21-045, was isolated from the rhizosphere soil beneath a Korean fir (Abies koreana) tree in Muju-gun, Jeollabuk-do, Korea. To elucidate its taxonomic status, multilocus sequence analysis was conducted using sequences of the internal transcribed spacer regions, the large subunit ribosomal RNA, and the actin gene. Phylogenetic analysis revealed that strain KNUF-21-045 clustered with Arthrographis globosa and Arthrographis arxii but formed a distinct and well-supported lineage. The strain grew optimally on oatmeal agar and tolerated temperatures from 15 to 42 °C, showing higher thermotolerance than A. globosa but slightly lower than the type species, Arthrographis kalrae. Microscopically, it exhibited hyaline, septate hyphae, simple or poorly differentiated conidiophores, and broad conidiogenous hyphae producing doliiform to cylindrical arthroconidia. Unlike A. globosa and A. arxii, the isolate produced terminal and intercalary chlamydospores, while a trichosporiella-like synasexual morph, present in A. kalrae and A. arxii, was absent. Based on its distinct phylogenetic position and unique morphological and physiological characteristics, strain KNUF-21-045 is identified as a novel species of Arthrographis, for which the name Arthrographis abieticola sp. nov. is proposed.

Mite-pathogenic Akanthomyces attenuatus JEF-147 was liquid-cultured to produce blastospores as an active ingredient of formulations, which is more practical and cost-effective method than currently used solid cultures although stress resistance remains a challenge. In this work, first starch- or glucose-based artificial liquid culture media were used to culture JEF-147 with high miticidal activity against two-spotted spider mites (Tetranychus urticae) in flask conditions. The starch-based medium produced significantly higher numbers of blastospores than the glucose-based medium. JEF-147 blastospores from the glucose-based medium showed faster pathogenesis than those from starch-based medium. This liquid cultured was scaled up in a 2.5-L bioreactor with the glucose-based medium and 1.0 v/v/m of air supply. Production of blastospores was initiated 36 h after inoculation, but active blastospore production was not observed even in 94 h. Alternatively, the glucose-based medium was supplemented with magnesium sulfate at 1% (w/w) in the same bioreactor conditions, and it produced large number of blastospores. This work suggests that JEF-147 blastospores from the glucose-based liquid culture could be used for mite control and the supplement of salt to the medium possibly ensures the production of blastospores in a scale-up conditions. Specific optimization of salt and culture parameters in the scale up conditions and field study would be essential works to be followed.

Foliicolous or leaf-dwelling lichens are mostly found in (sub-)tropical rainforests; due to their sensibility to environmental changes, they may serve as biological indicators for rainforest ecosystems. In Korea, the northward shift of subtropical conditions due to global climate change has emphasized the importance of understanding foliicolous lichen diversity and distribution, as they are now increasingly found in these latitudes. This study revises the taxonomy and distribution of foliicolous species in the family Strigulaceae in Korea through ITS-based identification and multigenetic analyses using four additional genetic markers (SSU, LSU, TEF1-α, and RPB2). The results support Racoplaca pelta sp. nov. and Reticula ambigua gen. nov. et sp. nov. as distinct phylogenetic lineages. Newly obtained ITS sequences confirmed that previously misidentified specimens of Strigula subelegans (KoLRI016349 and KoLRI016333) and Racoplaca melanobapha (KoLRI016334) correspond to S. multiformis and R. pelta, respectively. In addition, the distribution of Strigulaceae, once known only from Jeju Island within Korea, was found to extend to four additional southern islands: An, Ga-geo, Geo-mun, and Gwan-mae.

A fungal strain NIBRFGC000512623, belonging to the family Cucurbitariaceae, was isolated from a stink bug (Lelia decempunctata) collected from Gunwi-gun, Daegu, South Korea. Phylogenetic analyses based on the concatenated nucleotide sequences of internal transcribed spacer (ITS) regions and partial sequences of large subunit 28S rRNA, β-tubulin, and RNA polymerase II subunit genes revealed that the strain belonged to the genus Allocucurbitaria but occupied a distinct phylogenetic position. The strain NIBRFGC000512623 was compared with closely related species A. botulispora and A. Mori and morphologically distinguished from A. botulispora by its colony color on MEA medium (white vs. dark olive-brown), A. mori by the smaller size of its conidiogenous cells. According to molecular phylogeny and morphology, we suggested the new species Allocucurbitaria koreanum sp. nov. and provided a descriptive illustration.

Naematelia aurantialba, a rare yellow edible fungus with both nutritional and medicinal properties, is of significant importance in industrial cultivation due to its color-changing characteristics. This study was designed to develop novel color-changing germplasm resources and to explore associated functional genes. We applied aeronautical mutagenesis to the strains and utilized whole-genome resequencing to analyze the mutational profiles, thereby identifying candidate genes associated with color change. In the color-changed strains, we detected 201 SNPs and 307 InDels, predominantly located in the upstream (46.83%) and downstream (43.77%) regions of genes. By integrating SNP and InDels data, we identified seven mutational sites that were co-mutated in at least three strains. Gene annotation of these sites revealed 29 candidate genes, including three with unknown functions, which may significantly influence the color change trait in N. aurantialba. qRT-PCR results indicated significant differences in the expression of NAU27003649 between white and yellow strains, suggesting its potential role in the color variation. This research pioneers the application of aviation mutagenesis to generate new germplasm for N. aurantialba, offering new insights into the genetic basis of its color change traits.

Olive anthracnose, caused by Colletotrichum species, is one of the most destructive fungal diseases affecting olive fruit worldwide. With the expansion of olive cultivation into East Asia, including Jeju Island, South Korea, it is necessary to characterize local Colletotrichum populations. This study investigated Colletotrichum species associated with olive anthracnose in Korea and their pathogenicity. Using morphological characterization and multilocus phylogenetic analysis (ITS, GAPDH, CHS-1, ACT, and TUB2), we found that four Colletotrichum species are associated with olive anthracnose in Korea: C. fioriniae, C. nymphaeae, C. fructicola, and C. siamense. Pathogenicity tests confirmed that all four species cause typical anthracnose symptoms on olives, confirming their role as causal agents of olive anthracnose in Korea.

Several Pseudocercospora species were recognized as leaf spot pathogens on various vitaceous plants worldwide. Of them, Pseudocercospora vitis on Vitis spp. and Ps. ampelopsidis on Ampelopsis glandulosa var. heterophylla were reported to occur in Korea to date. The species diversity of the genus Pseudocercospora associated with vitaceous plants in Korea was revised in the scope of multigene sequence analyses and detailed morphological examinations. This study includes the introduction of new host finding for Ps. vitis, Vitis labrusca × Vitis vinifera "Campbell Early" in Korea, and one new species, Ps. neovitis sp. nov. on Vitis flexuosa. Illustrations of diseased plants with micrographs of pathogens, generated phylogenetic trees, and a discussion, including comparisons with related Pseudocercospora species are presented here.

Terrestrial isopods serve as key decomposers in soil ecosystems and harbor diverse microbial communities that may contribute to their ecological functions. However, specific mycobiome composition of terrestrial isopods remains unknown. Therefore, in this study, we investigated and compared the fungal communities associated with the two terrestrial isopods, Armadillidium vulgare and Spherillo obscurus, which co-occur in island habitats in South Korea. Through metabarcoding based on the internal transcribed spacer region, we characterized fungal communities using 16 individuals collected from the Heuksan and Eocheong Islands. In total, 252 operational taxonomic units were identified, of which 27 were shared between the two hosts. Comparatively, S. obscurus harbored a significantly more diverse and phylogenetically rich fungal community, including taxa from Ascomycota, Basidiomycota, and Mortierellomycota, whereas A. vulgare was largely dominated by Mycosphaerella (Dothideomycetes, Ascomycota). Alpha and beta diversity analyses revealed the host-associated enrichment, rather than the geographic location, as the primary factor influencing the mycobiome composition. Linear discriminant analysis further revealed host specialists, with distinct fungal taxa showing preferential associations with each isopod species. Our findings suggest that host identity strongly influences the fungal community assembly in isopods and that S. obscurus supports diverse ecological niches for fungal colonization. Overall, this study provides novel insights into host-fungus interactions and expands the current understanding of symbiotic mycobiomes in soil macroinvertebrates.

Cherry trees are the most widely planted landscape trees in Korea. They are also a vital tourist resource in many countries. However, cherry trees are frequently affected by brown shot-hole disease. In the early stages of this disease, brown, round spots appear on the leaves. As the symptoms worsen, some tissue falls off, forming shot hole-shaped lesions. Severely affected cherry trees may lose most leaves prematurely, reducing photosynthesis and affecting the number of blossoms the following year. Mycosphaerella cerasella has been identified as the primary causal pathogen of brown shot-hole disease in Korea. However, other fungal species can also cause shot-hole symptoms on plant leaves. Therefore, it is important to investigate the pathogens responsible for brown shot-hole disease in cherry trees. In this study, we isolated, identified, and analyzed the pathogenicity of fungi from cherry tree leaves infected with brown shot-hole disease collected from nationwide Korea. Our findings indicate that fungi from the genera Alternaria, Diaporthe, Epicoccum, and Botryosphaeria were frequently isolated from symptomatic leaves. Additionally, we observed regional differences in pathogen distribution. Based on these results, we propose that these four genera are the major fungal pathogens responsible for brown shot-hole disease in cherry trees in Korea.

The genus Golovinomyces (Erysiphaceae, Ascomycota) comprises obligate biotrophic fungi responsible for powdery mildew diseases on many economically important and wild plant species, mainly within the Asteraceae. From 1987 to 2024, we collected about 1000 samples of Golovinomyces spp. across Korea and performed morphological observation along with multi-locus sequence analyses (including internal transcribed spacer, large subunit, intergenic spacer, and glyceraldehyde-3-phosphate dehydrogenase). Resolving five previous ambiguous species complexes, Golovinomyces ambrosiae, Golovinomyces artemisiae, Golovinomyces biocellatus, Golovinomyces cichoracearum, and Golovinomyces orontii, clarified species boundaries and refined previous identifications. As a result, this study identified 21 Golovinomyces species, representing an increase from 15 species previously recorded in Korea. A new species, Golovinomyces physalidis, was described as the causal agent of powdery mildew on Physaliastrum echinatum and Physalis alkekengi var. franchetii. Additionally, five species (Golovinomyces chrysanthemi, Golovinomyces latisporus, Golovinomyces monardae, Golovinomyces montagnei, and Golovinomyces riedlianus) and three host plants (Achillea ptarmica var. acuminata, P. echinatum, and Xanthium italicum) were newly documented in Korea. The present findings establish an updated taxonomic framework for Golovinomyces species, thereby improving identification accuracy and enhancing disease management.