Mycobiology最新文献

Helvella, commonly known as saddle fungi, is a genus in the Helvellaceae family and is distributed globally. Recent comprehensive studies on Helvella have revealed that some Helvella species exhibit endemic traits and that many morphologically similar, cryptic species are phylogenetically distant. In this study, 202 Korean Helvella specimens collected between 1986 and 2023 were reevaluated through morphological analysis and phylogenetic characterization using barcode sequences, including nrLSU (nuclear Large Subunit Ribosomal DNA), hsp90 (Heat Shock Protein 90), and ITS (Internal Transcribed Spacer). The investigation confirmed the presence of at least 35 phylogenetic species in Korea. Among these, eight species (H. atroides, H. fistulosa, H. liquii, H. lobata, H. rugosa, H. subglabroides, H. sublactea, H. varia) were identified as previously unrecorded species in Korea, and seven new species (H. densipila, H. flavopus, H. macrospora, H. griseobrunnea, H. pseudolobata, H. parviflava, H. suborentitomentosa) were discovered. Of the 13 previously recorded Korean Helvella species, only three (H. ephippioides, H. macropus, H. orienticripsa) were confirmed, while the remaining ten species (H. acetabulum, H. atra, H. compressa, H. costifera, H. crispa, H. elastica, H. sublicia, H. fibrosa, H. lacunosa, H. pezizoides) were not detected in the samples studied. This study enhances our understanding of the distribution of Helvella species of Korea, revealing significant discrepancies between historical records and current findings. The discovery of new species and previously un-recorded species underscores the importance of continuous monitoring and reevaluation of fungal biodiversity.

This study was conducted to investigate the growth characteristics and morphology of Pleurotus ostreatus mycelium during co-cultivation with Pseudomonas putida. For selection of the most effective Pseudomonas species in coculture, Three strains of Pseudomonas putida and one strain of Pseudomonas fluorescens were co-cultured with heuktari, one of the varieties of P. ostreatus, on NPDA agar medium to observe the growth pattern of mycelium. It was found that the microorganism affecting mycelium growth during co-cultivation was P. putida KACC 10275, and co-cultivation of these two species resulted in enhanced mycelium growth on both NPDA and sawdust agar media. Furthermore, while primordium formation and fruit body development did not occur on plates inoculated only with heuktari, fruit bodies were observed only on plates where heuktari and P. putida were co-cultured, as confirmed by cultivation in the growth chamber for the same duration.

Small galls and white blisters with cup-like fungal structures were observed on the leaves of Machilus thunbergii (Lauraceae), a tree species native to East Asia. Based on its distinctive symptoms and aster-shaped spores, the causal agent was identified as Asteroconium saccardoi. Despite its unique characteristics, the genus Asteroconium remains taxonomically unresolved (incertae sedis) within the phylum Ascomycota due to the absence of both sequence data and available culture. The present study successfully obtained ITS and LSU rDNA sequences from its fresh spore masses formed on M. thunbergii. Phylogenetic analysis revealed that A. saccardoi belongs to the order Exobasidiales under Basidiomycota. Detailed morphological characteristics of basidia and basidiospores were documented, providing comprehensive insights into the taxonomy and phylogeny of Asteroconium within Exobasidiales.

An improved sporulation method for Pythium aphanidermatum on 10% V₈-juice agar was developed to generate substantial quantities of zoospores. We conducted experiments using a 4 × 4 factorial design to evaluate the effects of temperature (20, 25, 30, and 35 °C) and incubation time (2, 3, 4, and 5 days) on zoospore production from isolates HSv05 and KACC 48066. The results indicated that a temperature of 30 °C consistently yielded the highest numbers of zoospores across all incubation periods. Applying the same temperature (30 °C) and all incubation periods to other isolates (CCp03, CCp04, CCp05, HSv10, and KACC 40156) also resulted in higher numbers of zoospores regardless of incubation times compared with that under the control condition (25 °C and 2 days). Further virulence tests of isolate HSv05 revealed that high concentrations of zoospores (5 × 10² - 10⁵ zoospores/ml) induced severe rot symptoms; however, a low concentration of 10² zoospores/ml produced only considerably weak symptoms on inoculated potato tubers. No symptoms appeared in tubers inoculated with 0 (uninoculated control) or 10¹ zoospores/ml. These findings suggest that our sporulation method can help obtain adequate zoospores for various basic and applied studies, including pathogen identification, virulence assessment, resistance resource screening, and control strategy development.

During an investigation of Korean Ascomycetes in 2023, we found two undescribed species from South Korea. We analyzed them using a combined approach, including morphological and phylogenetic analyses of the rDNA regions (internal transcribed spacer and large subunit). The two species were identified to belong to the genus Geoglossum; the species G. simile and a new species named G. subdifforme sp. nov. The phylogenetic tree constructed using the ITS region showed that G. subdifforme is closely related to G. difforme. These species are distinguishable by certain morphological characteristics, particularly the size and septae of ascospores. Morphologically, G. simile is related to G. glabrum, but it is distinguishable by the morphological characteristics of paraphyses as well as ITS sequences. In this study, the descriptions, photographs, and phylogenetic relationships of these Geoglossum species are presented.

In this study, we aimed to develop simple sequence repeat (SSR) markers for evaluating resources in Armillaria ostoyae and examine their transferability to Armillaria gallica, related species. SSR markers were developed using the released A. ostoyae whole-genome sequence (GenBank assembly accession: GCA_900157425.1). The SSR regions were analyzed using the MISA (MIcroSAtellite identification tool) program. A total of 2319 SSR loci consisting of 922 (39.76%) mononucleotide, 763 (32.90%) trinucleotide, and 517 (22.29%) dinucleotide motifs were identified. Marker design involved an arbitrary choice of 150 SSR loci, considering motif abundance. A total of 22 strains of A. ostoyae were analyzed using the developed markers, and 105 markers were successfully amplified. The mean values of major allele frequency, number of alleles, expected heterozygosity, observed heterozygosity, and polymorphism information content (PIC) values were approximately 5.89, 5.4, 0.541, 0.255, and 0.504, respectively. A. gallica was analyzed, and 52 markers (49.5%) were successfully amplified to evaluate the transferability of the developed SSR markers. When these markers were used, the mean values of major allele frequency, number of alleles, expected heterozygosity, observed heterozygosity, and PIC were calculated to be approximately 0.615, 4.3, 0.517, 0.133, and 0.502, respectively. In conclusion, SSR markers were developed using the genome of A. ostoyae, and some of these markers exhibited transferability to A. gallica. These results can be used for resource evaluation of A. ostoyae and A. gallica.

Ambrosia fungi are well-known for their symbiotic interactions with ambrosia beetles, acting as a sole food source of larvae and adult beetles. As a first step to reveal these interactions, extensive survey on the fungal symbionts of ambrosia beetles dwelling in Korea. Eight fungal species isolated from 15 ambrosia beetle species were not known for their presence in Korea. Seven of these belonged to two orders of Ascomycota; Microascales (Ambrosiella beaveri, A. catenulate, and A. roeperi) and Ophiostomatales (Leptographium verrucosum, Raffaelea cyclorhipidii, R. subfusca, and Sporothrix eucastaneae) and one to Polyporales of Basidiomycota (Irpex subulatus). This is the first report of these species in Korea with taxonomic descriptions.

Chytridiomycota is the most species-rich phylum of basal lineage fungi with a worldwide distribution. Its species constitute essential components of freshwater ecosystems. However, the diversity of this group in Korea remains understudied. A survey of Chytridiales and Rhizophydiales fungi was conducted in soil and freshwater environments in Korea, and seven strains were isolated. Based on morphological and molecular data, a previously unidentified, novel Rhizophydium species was discovered, designated Rhizophydium multiplex sp. nov. In addition, Chytriomyces hyalinus and Globomyces pollinis-pini were isolated for the first time in Korea. Detailed descriptions and illustrations of the three species are provided. This study highlights the potential diversity of chytrid fungi in Korea.

Garlic (Allium sativum) is an indispensable ingredient for enriching and diversifying Indonesian cuisine taste. Indonesian people always use garlic for their daily dishes and any traditional foods. Due to its widespread culinary use, its availability in the market become critical. The main challenge to consistently growing this garlic is Fusarium oxysporum f. sp. cepae, which wilts Allium plants. The application of arbuscular mycorrhiza fungi (AMF) + Bacillus amyloliquefaciens B1 on local garlic varieties named Lumbu Hijau could effectively control F. oxysporum through in vitro and in vivo experiments. In the in vitro test, B. amyloliquefaciens B1 successfully suppressed the growth of F. oxysporum up to 53.41%. The consortium application in the greenhouse reduced disease incidence by up to 39.17%, and the efficacy of this biocontrol reached 84%. In addition, this approach also positively influenced plant growth, such as plant height, total wet shoot and root weight, and also tuber weight. As such, it is essential to use this consortium of microorganisms in field research and carry out a comprehensive investigation to identify any possible phenomena that may arise in the rhizosphere after application.

Laccases are enzymes capable of oxidizing phenolic compounds and are important tools in different industrial processes. Heterologous expression of laccases is of great interest in biotechnological applications but achieving high expression levels is challenging. Three different laccases have been identified in the chestnut blight fungus Cryphonectria parasitica, among which a tannic acid-inducible laccase (laccase3) was successfully expressed using Saccharomyces cerevisiae. To obtain high and stable expression of fungal laccases, we cloned the gene encoding an extracellular laccase (Laccase1) of C. parasitica into a yeast episomal vector, used the resulting vectors to transform S. cerevisiae, and optimized the culture conditions of the selected transformants for Laccase1 production. We also tested the significance of the signal peptide of Laccase1 in the secretion of expressed Laccase1 and compared it with the widely used rice amylase signal peptide. Among the four constructs tested using a yeast episomal vector, full-length Laccase1 containing an endogenous signal peptide, showed the highest laccase activity. Interestingly, the stability of the recombinant vector expressing laccase was lower than that of the mock transformant, suggesting a detrimental effect of the Laccase1-expressing vector on host cells. Thus, we optimized the culture conditions to produce Laccase1 and the resulting optimum culture conditions identified through one-factor-at-a -time (OFAT) were 2% sucrose; 3% yeast nitrogen base without amino acid; pH 5.0; and 30 °C. The laccase activity was found to be 2.2 U/mL in optimal culture conditions, resulting in a 6.5-fold increase compared to the conventional culture medium.