Wood-decay fungi (WDF) play a significant role in recycling nutrients, using enzymatic and mechanical processes to degrade wood. Designated as a biodiversity hot spot, Central Siberia is a geographically important region for understanding the spatial distribution and the evolutionary processes shaping biodiversity. There have been several studies of WDF diversity in Central Siberia, but identification of species was based on morphological characteristics, lacking detailed descriptions and molecular data. Thus, the aim of this study was to identify WDF in Central Siberia, regarding the degradation of host trees based on both morphological and molecular analyses. We collected 106 WDF samples from Krasnoyarsk and the Republic of Khakassia in 2014 and 2017, and identified a total of 52 fungal species from six main host tree genera. In order to assess the host preference of the WDF, we examined previous literature, and data from this study. We confirmed a division in host preference of WDF between gymnosperms and angiosperms. DNA-based identification and host preference assessment of the WDF provide preliminary data on WDF diversity and their role in nutrient cycles in the ecosystem of Central Siberia. To fully understand WDF diversity in Central Siberia, continuous long-term surveys, including DNA sequence data, are needed.

Fungal species in the genera Armillaria and Desarmillaria (Physalacriaceae, Agaricales) are well known for their symbiotic relationships with Gastrodia elata and Polyporus umbellatus, important components of traditional medicine in Asia. In addition, some species in these genera cause Armillaria root disease, which has had a negative economic impact by damaging and destroying urban, horticultural and forest trees. Five species within Armillaria and Desarmillaria have been previously reported in South Korea, based primarily on basidioma morphology: A. cepistipes, A. gallica, A. mellea, A. ostoyae and D. tabescens (reported as A. tabescens). This study re‐evaluated 60 specimens of Armillaria and Desarmillaria using morphological features and molecular phylogenetic analyses of the ITS and partial translation elongation factor‐1α (tef1) sequences. In addition, spatial distributions of each Armillaria and Desarmillaria species in South Korea were determined from combined data based on basidioma collections and environmental DNA (eDNA). Six species (A. cepestipes, A. gallica, A. mellea, A. nabsnona, A. ostoyae and D. tabescens) and three lineages of A. gallica (A. gallica clade 1–3) were identified in South Korea from both specimens and eDNA. Most of the basidioma specimens used in this study were previously identified as A. mellea; however, in this study, no basidioma specimens were identified as A. mellea, although this species was detected on Jeju Island from eDNA samples. The detection of A. nabsnona was a new report for South Korea. Consistent with previous phylogenetic studies, the tef1 analysis had better resolution than the ITS analysis. These distribution data of Armillaria and Desarmillaria species will contribute to better management of Armillaria root disease as well as cultivation of G. elata and P. umbellatus in South Korea.

Trees in forest ecosystems constantly interact with the soil fungal community, and this interaction plays a key role in nutrient cycling. The diversity of soil fungal communities is affected by both environmental factors and host tree species. We investigated the influence of both of these factors by examining the total fungal communities in the rhizospheric soil of climax tree species that have similar ecological roles (Carpinus cordata, an ectomycorrhizal [ECM] tree, and Fraxinus rhynchophylla, an arbuscular mycorrhizal [AM] tree) in temperate forests with continental climates of Mt. Jeombong, South Korea. Fungal communities were assessed by Illumina-MiSeq sequencing the internal transcribed spacer (ITS) region of environmental DNA, and comparing their environmental factors (season and soil properties). We found that soil fungi of the two forest types differed in terms of community structure and ecological guild composition. The total fungal community composition changed significantly with seasons and soil properties in the F. rhynchophylla forest, but not in the C. cordata forest. However, potassium and carbon were significantly correlated with fungal diversity in both forests, and a positive correlation was found only between symbiotrophs of C. cordata and the carbon to nitrogen (C/N) ratio. Thus, the effects of environmental factors on soil fungal communities depended on the host trees, but some factors were common in both forests. Our results indicate that individual tree species should be considered when anticipating how the fungal communities will respond to environmental change.

The pine mushroom (Tricholoma matsutake; Agaricales, Tricholomataceae) is an ectomycorrhizal fungus that produces a commercially valuable, edible mushrooms. Attempts to artificially cultivate T. matsutake has so far been unsuccessful. One method used to induce T. matsutake to produce fruiting bodies of in the wild is shiro (mycelial aggregations of T. matsutake) transplantation. In vitro ectomycorrhization of T. matsutake with seedlings of Pinus densiflora has been successful, but field trials showed limited production of fruiting bodies. Few studies have been done to test what happens after transplantation in the wild, whether T. matsutake persists on the pine seedling roots or gets replaced by other fungi. Here, we investigated the composition and the interaction of the root fungal microbiome of P. densiflora seedlings inoculated with T. matsutake over a 3 year period after field transplantation, using high-throughput sequencing. We found a decline of T. matsutake colonization on pine roots and succession of mycorrhizal fungi as P. densiflora seedlings grew. Early on, roots were colonized by fast-growing, saprotrophic Ascomycota, then later replaced by early stage ectomycorrhiza such as Wilcoxina. At the end, more competitive Suillus species dominated the host roots. Most of the major OTUs had negative or neutral correlation with T. matsutake, but several saprotrophic/plant pathogenic/mycoparasitic species in genera Fusarium, Oidiodendron, and Trichoderma had positive correlation with T. matsutake. Four keystone species were identified during succession; two species (Fusarium oxysporum, and F. trincintum) had a positive correlation with T. matsutake, while the other two had a negative correlation (Suillus granulatus, Cylindrocarpon pauciseptatum). These findings have important implications for further studies on the artificial cultivation of T. matsutake.

Macrofungi play important roles in forest ecology as wood decayers, symbionts, and pathogens of living trees. For the effective forest management, it is imperative to have a comprehensive overview of macrofungi diversity in specific areas. As a part of the National Institute of Biological Resources projects for discovering indigenous fungi in Korea, we collected macrofungi in Gayasan National Park from 2017 to 2018. These specimens were identified based on morphological characteristics and sequence analysis of internal transcribed spacer (ITS) or the nuclear large subunit rRNA (LSU) region. We discovered 17 macrofungi new to Korea: