A Novel Acremonium Species Isolated from Air Samples in Korea.

The aim of this study was to characterize a new fungal species, Acremonium conglutinatum, isolated from air samples collected in Wando, South Korea. Phylogenetic analysis based on the internal transcribed spacer and large subunit regions revealed its unique position within the genus Acremonium. The isolated strain displayed distinct morphological characteristics, including ellipsoid or bent-ellipsoid conidia formed in clusters on the phialides. These features differentiate the new species from closely related species within the genus. This study describes the morphological and molecular characteristics of A. conglutinatum and emphasizes its phylogenetic relationships with other Acremonium spp. The identification of this novel species contributes to our understanding of the diversity and ecological role of Acremonium.

Asymbiotic Spore Production of Rhizoglomus intraradices in a Medium Containing Myristate.

This study examined the effects of myristate on an asymbiotic culture of Rhizoglomus intraradices, a species of arbuscular mycorrhizal fungi (AMF; Glomeromycota). Mycelial growth and sporulation in a modified medium containing myristate were observed. The findings demonstrated that myristate induced R. intraradices spore formation, with daughter spores having a smaller diameter than the parent spores. This observation is consistent with previous studies on other Rhizoglomus species. Further studies are needed to investigate the potential for continuous culture, mass production using daughter spores, and the application of AMF colonization techniques in plants.

Community of Endophytic Fungi from Alpine Conifers on Mt. Seorak.

Endophytic fungi occupy various ecological niches, which reinforces their diversity. As few studies have investigated the endophytic fungi of alpine conifers, we focused on four species of alpine conifers in this study-Abies nephrolepis, Pinus pumila, Taxus cuspidata var. nana, and Thuja koraiensis-and examined them for endophytic fungi. A total of 108 endophytic fungi were isolated. There were four taxa in A. nephrolepis, 12 in P. pumila, 18 in T. cuspidata var. nana, and 17 in T. koraiensis; these were divided into five classes: Agaricomycetes (3.2%), Dothideomycetes (29.0%), Leotiomycetes (15.0%), Sordariomycetes (41.9%), and Orbiliomycetes (1.6%). The most prevalent fungi were Sydowia polyspora (22.7%) and Xylariaceae sp. (22.7%) in P. pumila, Phomopsis juglandina (16.1%) in T. cuspidata var. nana, and Thuja-endophytes sp. 1 (70.0%) in T. koraiensis. However, there was no dominant species growing in A. nephrolepis. Some host plants were analyzed using next-generation sequencing. We obtained 4618 reads for A. nephrolepis and 2268 reads for T. koraiensis. At the genus level, the top three endophytic fungi were Ophiostomataceae_uc (64.6%), Nectriaceae_uc (15.5%), and unclassified organism (18.0%) in A. nephrolepis and Nectriaceae_uc (41.9%), Ophiostomataceae_uc (41.8%), and Magnaporthaceae_uc (9.2%) in T. koraiensis. Our results show that there are different communities of endophytic fungi among different host plants, even if the host plants are in the same region. Such ecological niches are important in terms of the ecological restoration of alpine conifers.

Effect of Temperature, pH, and Media on the Mycelial Growth of Tuber koreanum.

Members of the genus Tuber are ectomycorrhizal fungi; this genus includes more than 180 species worldwide. In the present study, the optimal pH, temperature, and medium suitable for the mycelial growth of the Korean truffle, Tuber koreanum, were determined. Mycelium of T. koreanum, isolated from fruiting bodies collected in Korea, was used to investigate the effects of these environmental factors. The results showed that malt extract agar and potato dextrose agar were the most suitable for the mycelial growth of T. koreanum when cultured at a pH of 6.0 at 25 °C for 30 days.

Mycorrhization of Quercus spp. with Tuber huidongense and T. himalayense Collected in Korea.

Fungi of the genus Tuber are ectomycorrhizal fungi that form a symbiotic relationship mainly with oak and hazel trees. Tuber spp. exhibit a highly selective host plant preference; thus, for cultivation purposes it is important to select an appropriate host plant for successful mycorrhization. In addition, as mycorrhizal characteristics differ according to Tuber spp., it is necessary to understand the differences in mycorrhizae according to the fungal species. Tuber huidongense and Tuber himalayense were recently discovered in Korea; therefore, we used spore suspensions from these two species to inoculate two species of oak trees, Quercus acutissima and Quercus dentata, to compare colonization rates and morphologies of the mycorrhizae. The colonization rates demonstrated that the different Tuber spp. favored different host plant species. In addition, unique morphological and anatomical characteristics were observed for T. huidongense and T. himalayense depending on the host species. These findings can lead to new economically important agricultural activities related to truffle cultivation in Korea.

Diversity and community structure of ectomycorrhizal mycorrhizal fungi in roots and rhizosphere soil of Abies koreana and Taxus cuspidata in Mt. Halla.

In this study, the roots and rhizosphere soil of Abies koreana and Taxus cuspidata were collected from sites at two different altitudes on Mt. Halla. Ectomycorrhizal fungi (EMF) were identified by Illumina MiSeq sequencing. The proportion of EMF from the roots was 89% in A. koreana and 69% in T. cuspidata. Among EMF in rhizosphere soils, the genus Russula was the most abundant in roots of A. koreana (p < 0.05). The altitude did not affect the biodiversity of EMF communities but influenced fungal community composition. However, the host plants had the most significant effect on EMF communities. The result of the EMF community analysis showed that even if the EMF were isolated from the same altitudes, the EMF communities differed according to the host plant. The community similarity index of EMF in the roots of A. koreana was higher than that of T. cuspidata (p < 0.05). The results show that both altitude and host plants influenced the structure of EMF communities. Conifers inhabiting harsh sub-alpine environments rely strongly on symbiotic relationships with EMF. A. koreana is an endangered species with a higher host specificity of EMF and climate change vulnerability than T. cuspidata. This study provides insights into the EMF communities, which are symbionts of A. koreana, and our critical findings may be used to restore A. koreana.

Diversity, Distribution, and Host Plant of Endophytic Fungi: A Focus on Korea.

Endophytic fungi occupy inner plant tissues, which results in various interactions between the fungus and host. Studies on endophytic fungi have been conducted in Korea for over 30 years. This paper summarizes the published results of those studies. The endophytic fungi of approximately 132 plant species in Korea have been studied since the 1990s, resulting in over 118 publications. The host plants featured in these studies comprised 3 species of mosses, 34 species of woody plants, and 95 species of herbaceous plants. At the family level, the most studied plants were members of the Poaceae family, covering 18 species. Regionally, these studies were conducted throughout Korea, but over half of the studies were conducted in Gyeongsangbuk-do, Gangwon-do, and Chungcheongnam-do. Relatively few studies have been conducted in a metropolis such as Seoul. We confirmed 5 phyla, 16 classes, 49 orders, 135 families, 305 genera, and 855 taxa of endophytic fungi, excluding Incertae sedis, whose relationship with others are unknown. Most of the endophytic fungi belonged to Ascomycota (93.2%), and a few belonged to Basidiomycota (3.6%). Since the diversity of endophytic fungi differs depending on the host plant, plant tissue, and distribution region, future studies should be conducted on multiple host plants and in various regions. Future studies on endophytic fungi are expected to broaden, including genomics and taxonomic and ecological studies of secondary metabolites.

Report on a New Truffle Species, Tuber koreanum sp. nov., from Korea.

The truffle and ectomycorrhizal roots formed by Tuber sp. were collected from the rhizosphere of Quercus aliena in Korea. The morphological characteristics of the ascoma, and molecular phylogenetic analysis using sequences from the internal transcribed spacer (ITS) and large subunit (LSU) of ribosomal DNA, translation elongation factor 1-alpha (TEF), and RNA polymerase second largest subunit (RPB2) regions confirmed the distinct morphology of the truffle. This truffle belongs to a monophyletic clade among the other Tuber species in the phylogeny. This study describes the truffle, Tuber koreanum, as a new species reported from Korea.

Taxonomy of Arthrinium minutisporum sp. nov., Pezicula neosporulosa, and Acrocalymma pterocarpi: New Records from Soil in Korea.

The strains 17E-042, 17E-039, and NC13-171 belong to Ascomycota and were isolated from soil collected from Sancheong-gun and Yeongam-gun, Korea. The strain 17E-042 produced white mycelial colonies that developed a sienna color with a round margin on potato dextrose agar (PDA), and the reverse side developed a light sienna color. Morphologically, this strain was similar to the strains of Arthrinium phragmites and A. hydei, but the shorter conidial size of the newly identified strain (17E-042) was distinct. The strain 17E-039 produced macroconidia that were pale yellow to orange-brown, elongated-ellipsoid to oblong, round at both ends, primarily straight but sometimes slightly curved, 0-septate, thin-walled, and filled with numerous droplets, having diameters of 20.4-34.3 × 8.0-12.0 µm. And the strain NC13-171 formed hyaline to light brown chlamydospores, solitary or in a chain. Multigene phylogenetic analyses were conducted using sequence data obtained from internal transcribed spacer (ITS) regions, 28S rDNA large subunit (LSU), ß-tubulin (TUB2), translation elongation factor 1-alpha (TEF1-α), and RNA polymerase II large subunit (RPB2) genes. The results of molecular phylogeny, the detailed descriptions and illustrations of each species strongly support our proposal that these strains from soil in Korea be designated as Arthrinium minutisporum sp. nov. and two new records of Pezicula neosporulosa and Acrocalymma pterocarpi.

Acaulosproa koreana, a New Species of Arbuscular Mycorrhizal Fungi (Glomeromycota) Associated with Roots of Woody Plants in Korea.

A new species of arbuscular mycorrhizal fungi (Glomeromycota), Acaulospora koreana, was isolated from forest soils in South Korea. This novel fungus was collected from the rhizosphere of Lindera obtusiloba and Styrax obassia in forest and propagated with Sorghum bicolor in pot. Morphological characteristics of spores of A. koreana are rarely distinguished from Acaulospora mellea, which is reported as one of the most abundant mycorrhizal species in Korea. However, molecular evidence of rDNA sequence using improved primers for glomeromycotan fungal identification strongly supported that A. koreana is different from A. mellea but also any other species belonging to the genus Acaulospora. This is the first novel glomeromycatan fungus introduced in South Korea, but it suggests that there is a high possibility for discovering new arbuscular mycorrhizal fungi considering the abundance of plant species and advanced phylogenetic analysis technique.

Effects of Arbuscular Mycorrhizal Fungi and Soil Conditions on Crop Plant Growth.

We investigated the effects on various crops of inoculation with species of arbuscular mycorrhizal fungi (AMF) in soils from different sources and selected AMF species suitable for domestic environment-friendly farming. Effects on plants varied with the AMF species used. In carrot, Scutellospora heterogama, Acaulospora longula, and Funneliformis mosseae had a positive effect on growth of the host, whereas AMF had only weak effects on the growth of red pepper and leek. AMF inoculation had positive effects on the growth of carrot and sorghum. The results of this study indicate the nature of the relationship between soil, plants, and AMF; this study therefore has important implications for the future use of AMF in environment-friendly agriculture.

Differences among Endophytic Fungal Communities Isolated from the Roots of Cephalanthera longibracteata Collected from Different Sites in Korea.

Orchidaceous plants have symbiotic relationships with endophytic fungi, including mycorrhizal fungi, which play important roles in the seed germination and growth of the host plants. In this study, endophytic fungal communities isolated from the roots of Cephalanthera longibracteata collected from three different sites in Korea were analyzed, and it was determined whether fungal communities were preferentially correlated with the sites. The fungal isolates were identified by sequence analysis of the internal transcribed spacer regions of rDNA. In total, 30 species of endophytic fungi, including two species of mycorrhizal fungi belonging to the genus Tulasnella, were identified. Leptodontidium orchidicola showed the highest frequency and was isolated from all root samples. Species diversity and richness were not significantly different among sites. However, the community structure of the endophytic fungi significantly differed among sites, suggesting that the site characteristics affected the community composition of the endophytic fungi colonizing the roots of C. longibracteata. Our findings will aid in developing methods involving the use of symbiotic fungi for orchid conservation and restoration in native habitats.

Two Endophytic Diaporthe Species Isolated from the Leaves of Astragalus membranaceus in Korea.

We characterized two endophyte fungi from the leaves of Astragalus membranaceus in Korea. The isolated strains were identified on the basis of the morphological characters and sequences analysis of the internal transcribed spacer and large subunit regions of the rDNA and ß-tubulin gene. To the best of our knowledge, this is the first report of Diaporthe oncostoma and Diaporthe infecunda in Korea, and we have provided descriptions and figures.

Community Structures of Arbuscular Mycorrhizal Fungi in Soils and Plant Roots Inhabiting Abandoned Mines of Korea.

In this study, we collected rhizosphere soils and root samples from a post-mining area and a natural forest area in Jecheon, Korea. We extracted spores of arbuscular mycorrhizal fungi (AMF) from rhizospheres, and then examined the sequences of 18S rDNA genes of the AMF from the collected roots of plants. We compared the AMF communities in the post-mining area and the natural forest area by sequence analysis of the AMF spores from soils and of the AMF clones from roots. Consequently, we confirmed that the structure of AMF communities varied between the post-mining area and the natural forest area and showed significant relationship with heavy metal contents in soils. These results suggest that heavy metal contamination by mining activity significantly affects the AMF community structure.

Growth Characteristics of Rhizophagus clarus Strains and Their Effects on the Growth of Host Plants.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level.

Diversity of endophytic fungi isolated from korean ginseng leaves.

We investigated the diversity of the foliar endophytes of Korean ginseng. Endophytic fungi were isolated from healthy leaves of mountain-cultivated ginseng (MCG) and field-cultivated ginseng (FCG) at 4 sites in Chungbuk Province. A total of 24 species of fungal endophytes were identified using molecular approaches. Additionally, the diversity of these endophytic fungi was compared between MCG and FCG. The major isolated endophytes were Edenia gomezpompae and Gibberella moniliformis in the MCG and FCG samples, respectively. The results suggest that ginseng endophytes have different community structures in different environments, and this understanding may prove useful in ginseng cultivation.

Root Age-Dependent Changes in Arbuscular Mycorrhizal Fungal Communities Colonizing Roots of Panax ginseng.

In this study, we examined arbuscular mycorrhizal fungal (AMF) community structure colonizing field-cultivated ginseng roots according of different ages, such as 1- to 5-year-old plant, collected from Geumsan-gun, Korea. A total of seven AMF species namely, Funnelliformis caledonium, F. moseae, Gigaspora margarita, Paraglomus laccatum, P. occultum, Rhizophagus irregularis, and Scutellospora heterogama were identified from the roots using cloning, PCR-restriction fragment length polymorphism and sequence analysis of the large subunit region in rDNA. AMF species diversity in the ginseng roots decreased with the increase in root age because of the decreased species evenness. In addition, the community structures of AMF in the roots became more uniform. These results suggest that the age of ginseng affects mycorrhizal colonization and its community structure.

Diversity of arbuscular mycorrhizal fungi and their roles in ecosystems.

Arbuscular mycorrhizal fungi (AMF) have mutualistic relationships with more than 80% of terrestrial plant species. This symbiotic relationship is ancient and would have had important roles in establishment of plants on land. Despite their abundance and wide range of relationship with plant species, AMF have shown low species diversity. However, molecular studies have suggested that diversity of these fungi may be much higher, and genetic variation of AMF is very high within a species and even within a single spore. Despite low diversity and lack of host specificity, various functions have been associated with plant growth responses to arbuscular mycorrhizal fungal colonization. In addition, different community composition of AMF affects plants differently, and plays a potential role in ecosystem variability and productivity. AMF have high functional diversity because different combinations of host plants and AMF have different effects on the various aspects of symbiosis. Consequently, recent studies have focused on the different functions of AMF according to their genetic resource and their roles in ecosystem functioning. This review summarizes taxonomic, genetic, and functional diversities of AMF and their roles in natural ecosystems.

Ectomycorrhizal Fungal Communities of Red Pine (Pinus densiflora) Seedlings in Disturbed Sites and Undisturbed Old Forest Sites.

This study aimed to investigate differences in ectomycorrhizal (ECM) fungal communities between disturbed sites and undisturbed old forest sites. ECM root tips of Pinus densiflora were collected from 4 sites disturbed by human activities and 3 undisturbed old forest sites adjacent to the disturbed sites. Results in this study showed that the number of ECM root tips, species diversity, and number of species were significantly higher in the disturbed sites than in the undisturbed sites, suggesting that the ECM fungal community structure was affected by the degree of disturbance.

Diversity and seasonal variation of endophytic fungi isolated from three conifers in mt. Taehwa, Korea.

The needled leaves of three conifer species were collected in Mt. Taehwa during different seasons of the year. Total 59 isolates and 19 species of endophytic fungi were isolated from the leaves and identified using morphological and molecular characteristics. As a result, Shannon index was different in its host plant; Larix kaempferi had a highest value of species diversity. According to the sampling season, 9 species of 19 species were isolated during fall season. The results suggest that the existing of host plant and sampling season are major factors of distribution of endophytic fungi.