Uncharted Diversity and Ecology of Saprolegniaceae (Oomycota) in Freshwater Environments

The fungal-like family Saprolegniaceae (Oomycota), also called “water mold,” includes mostly aquatic saprophytes as well as notorious aquatic animal pathogens. Most studies on Saprolegniaceae have been biased toward pathogenic species that are important to aquaculture rather than saprotrophic species, despite the latter’s crucial roles in carbon cycling of freshwater ecosystems. Few attempts have been made to study the diversity and ecology of Saprolegniaceae; thus, their ecological role is not well-known. During a survey of oomycetes between 2016 and 2021, we investigated the diversity and distribution of culturable Saprolegniaceae species in freshwater ecosystems of Korea. In the present study, members of Saprolegniaceae were isolated and identified at species level based on their cultural, morphological, and molecular phylogenetic analyses. Furthermore, substrate preference and seasonal dynamics for each were examined. Most of the species were previously reported as animal pathogens; however, in the present study, they were often isolated from other freshwater substrates, such as plant debris, algae, water, and soil sediment. The relative abundance of Saprolegniaceae was higher in the cold to cool season than that in the warm to hot season of Korea. This study enhances our understanding of the diversity and ecological attributes of Saprolegniaceae in freshwater ecosystems.

Two New Species and Three New Records of Ascomycetes in Korea

During a survey of plant-inhabiting fungi and water niches from Korea, noteworthy fungi were collected; among them, two new species, Paracamarosporium noviaquum sp. nov. and Phyllosticta gwangjuensis sp. nov., are described based on morphology and multi-gene phylogenies. Paracamarosporium noviaquum was characterized by its production of 1-celled and 2-celled conidia, forming conidiomata on only potato dextrose agar medium. Phyllosticta gwangjuensis was characterized by conidia hyaline, ovoid to ellipsoid shape, rounded at both ends, containing numerous guttulae or with a single large central guttule. Additional species were identified as Cosmospora lavitskiae, Monochaetia cameliae, and Roussoella doimaesalongensis, which are reported as new record species from Korea. Detailed descriptions and illustrations of these taxa are provided herein.

Seven Undescribed Aspergillus Species from Different Niches in Korea

An investigation of species of the genus Aspergillus present in arthropod, freshwater, and soil led to the discovery of seven undescribed species in Korea. Based on their morphological characteristics and molecular phylogeny analyses using a combined data set of b-tubulin (BenA) and calmodulin (CaM) sequences, the isolated strains CNUFC IGS2-5, CNUFC YJ1-19, CNUFC WD27, CNUFC U8-70, CNUFC AS2-24, CNUFC S32-1, and CNUFC U7-48, were identified as Aspergillus brunneoviolaceus, A. capensis, A. floccosus, A. inflatus, A. parvulus, A.polyporicola, and A. spelaeus, respectively. In the present study, the detailed morphological descriptions and phylogenetic relationships of these species are provided.

New Species and Eight Undescribed Species Belonging to the Families Aspergillaceae and Trichocomaceae in Korea

During a survey of fungal diversity associated with insects, mud, soil, and freshwater niches in different areas in Korea, nine interesting fungal strains were isolated. Based on their morphological characteristics and molecular phylogeny analyses, using a combined data set of β-tubulin (BenA), calmodulin (CaM), and second largest subunit of RNA polymerase (RPB2) sequences, the strains CNUFC AM-44, CNUFC JCW3-4, CNUFC S708, CNUFC WT202, CNUFC AS1-29, CNUFC JCW3-5, CNUFC JDP37, and CNUFC JDP62 were identified as Aspergillus alabamensis, A. floridensis, A. subversicolor, Penicillium flavigenum, P. laevigatum, P. lenticrescens, Talaromyces adpressus, and T. beijingensis, respectively. The strain CNUFC JT1301 belongs to series Westlingiorum in section Citrina and is phylogenetically related to P. manginii.However, slow growth when cultivated on CYA, MEA, CREA is observed and the property can be used to easily distinguish the new species from these species. Additionally, P. manginii is known to produce sclerotia, while CNUFC JT1301 strain does not. Herein, the new fungal species is proposed as P. aquadulcis sp. nov. Eight species, A. alabamensis, A. floridensis, A. subversicolor, P. flavigenum, P. laevigatum, P. lenticrescens, T. adpressus, and T. beijingensis, have not been previously reported in Korea. The present study expands the known distribution of fungal species belonging to the families Aspergillaceae and Trichocomaceae in Korea.

Seven New Records of Penicillium Species Belonging to Section Lanata-Divaricata in Korea

Penicillium species are known to be ubiquitous environmental saprophytes. In the survey of diversity of genus Penicillium , seven new records of Penicillium species belonging to section Lanata-Divaricata were isolated from freshwater and soil samples collected from different locations in Korea. Based on morphological characteristics and multilocus phylogenetic analysis of the rDNA internal transcribed spacer region (ITS), β-tubulin (BenA), and calmodulin (CaM) genes, the isolated strains were identified as P. annulatum, P. camponotum, P. echinulonalgiovense, P. globosum, P. limosum, P. onobense, and P. yunnanense, respectively. This study presents detailed phylogenetic analyses and morphological descriptions of these species that contribute to section Lanata-Divaricata in Korea.

Six Newly Recorded Fungal Taxa from Freshwater Niche in Korea

Six interesting fungal strains were isolated during a survey of fungal diversity associated with freshwater; these strains were designated as CNUFC YJW2-22, CNUFC MSW11-6-2, CNUFC HRS5-3, CNUFC MSW242-6, CNUFC DMW2-2, and CNUFC CPWS-1. Based on a polyphasic approach including phylogenetic analyses of internal transcribed space (ITS), large subunit (LSU), beta-tubulin (BenA), and calmodulin (CaM) gene sequences, morphological analyses, the six strains were found to be identical to Acremonium guillematii, Cadophora novi-eboraci, Lectera nordwiniana, Mycoarthris corallina, Talaromyces siamensis, and Tetracladium globosum, respectively. To our knowledge, these are the first records of the rare Lectera, Mycoarthris, and Tetracladium genera in Korea, and the first reports of A. guillematii, C. novi-eboraci, L. nordwiniana, M. corallina, T. siamensis, and Te. globosum in a freshwater environment.

Seven New Records of Penicillium Species Belonging to Section Lanata-Divaricata in Korea

Penicillium species are known to be ubiquitous environmental saprophytes. In the survey of diversity of genus Penicillium , seven new records of Penicillium species belonging to section Lanata-Divaricata were isolated from freshwater and soil samples collected from different locations in Korea. Based on morphological characteristics and multilocus phylogenetic analysis of the rDNA internal transcribed spacer region (ITS), β-tubulin (BenA), and calmodulin (CaM) genes, the isolated strains were identified as P. annulatum, P. camponotum, P. echinulonalgiovense, P. globosum, P. limosum, P. onobense, and P. yunnanense, respectively. This study presents detailed phylogenetic analyses and morphological descriptions of these species that contribute to section Lanata-Divaricata in Korea.

Six Newly Recorded Fungal Taxa from Freshwater Niche in Korea

Six interesting fungal strains were isolated during a survey of fungal diversity associated with freshwater; these strains were designated as CNUFC YJW2-22, CNUFC MSW11-6-2, CNUFC HRS5-3, CNUFC MSW242-6, CNUFC DMW2-2, and CNUFC CPWS-1. Based on a polyphasic approach including phylogenetic analyses of internal transcribed space (ITS), large subunit (LSU), beta-tubulin (BenA), and calmodulin (CaM) gene sequences, morphological analyses, the six strains were found to be identical to Acremonium guillematii, Cadophora novi-eboraci, Lectera nordwiniana, Mycoarthris corallina, Talaromyces siamensis, and Tetracladium globosum, respectively. To our knowledge, these are the first records of the rare Lectera, Mycoarthris, and Tetracladium genera in Korea, and the first reports of A. guillematii, C. novi-eboraci, L. nordwiniana, M. corallina, T. siamensis, and Te. globosum in a freshwater environment.

Isolation and Characterization of Four Unrecorded Mucor Species in Korea

During an investigation of fungi of the order Mucorales from freshwater and sediment samplesin Korea, we isolated six strains, NNIBRFG6649, NNIBRFG6255, NNIBRFG1498, CNUFCYJ13,CNUFC-YR7, and NNIBRFG2739. The morphology and phylogeny of these strains wereanalyzed. Based on the morphological characteristics and molecular data from internal transcribedspacer (ITS) region, the isolates NNIBRFG6649 and NNIBRFG6255 were identified asMucor abundans, and M. aligarensis, respectively. The isolates NNIBRFG1498 and CNUFC-YJ13were identified as M. moelleri, whereas the isolates CNUFC-YR7 and NNIBRFG2739 were identifiedas M. heterogamus. To the best of our knowledge, M. abundans, M. aligarensis, M. moelleri,and M. heterogamus have not yet been reported in Korea.

Isolation and Characterization of Four Unrecorded Mucor Species in Korea

During an investigation of fungi of the order Mucorales from freshwater and sediment samplesin Korea, we isolated six strains, NNIBRFG6649, NNIBRFG6255, NNIBRFG1498, CNUFCYJ13,CNUFC-YR7, and NNIBRFG2739. The morphology and phylogeny of these strains wereanalyzed. Based on the morphological characteristics and molecular data from internal transcribedspacer (ITS) region, the isolates NNIBRFG6649 and NNIBRFG6255 were identified asMucor abundans, and M. aligarensis, respectively. The isolates NNIBRFG1498 and CNUFC-YJ13were identified as M. moelleri, whereas the isolates CNUFC-YR7 and NNIBRFG2739 were identifiedas M. heterogamus. To the best of our knowledge, M. abundans, M. aligarensis, M. moelleri,and M. heterogamus have not yet been reported in Korea.

Isolation and Characterization of Two Rare Mucoralean Species with Specific Habitats

The order Mucorales, the largest in number of species within the Mucoromycotina, comprises typically fast-growing saprotrophic fungi. During a study of the fungal diversity of undiscovered taxa in Korea, two novel mucoralean strains, CNUFC-GWD3-9 and CNUFC-EGF1-4, were isolated from specific habitats including freshwater and fecal samples, respectively. On the basis of their morphological characteristics and sequence analyses of internal transcribed spacer and large subunit ribosomal DNA, the CNUFC-GWD3-9 and CNUFC-EGF1-4 isolates were confirmed to be Gilbertella persicaria and Pilobolus crystallinus, respectively. It is ecologically, pathologically, and mycologically significant to find such rare zygomycetous fungi in such specific habitats.

Isolation and Characterization of Three Zygomycetous Fungi in Korea: Backusella circina, Circinella muscae, and Mucor ramosissimus

While surveying undiscovered fungal taxa in Korea, three rare zygomycetous fungal strains, CNUFC-PTF2-1, CNUFC-TF3-1, and CNUFC-ESAF3-1, were isolated from soil, leaf, and freshwater samples, respectively. The strains were analyzed morphologically as well as phylogenetically based on the internal transcribed spacer region and 28S rDNA sequences. Sequence analysis of the two loci revealed that the isolates, CNUFC-PTF2-1, CNUFC-TF3-1, and CNUFC-ESAF3-1, were identified as Backusella circina, Circinella muscae, and Mucor ramosissimus, respectively. These species have not yet been previously described in Korea.

Four New Records of Ascomycete Species from Korea

While evaluating fungal diversity in freshwater, grasshopper feces, and soil collected at Dokdo Island in Korea, four fungal strains designated CNUFC-DDS14-1, CNUFC-GHD05-1, CNUFC-DDS47-1, and CNUFC-NDR5-2 were isolated. Based on combination studies using phylogenies and morphological characteristics, the isolates were confirmed as Ascodesmis sphaerospora, Chaetomella raphigera, Gibellulopsis nigrescens, and Myrmecridium schulzeri, respectively. This is the first records of these four species from Korea.

Isolation and Characterization of Three Unrecorded Zygomycete Fungi in Korea: Cunninghamella bertholletiae, Cunninghamella echinulata, and Cunninghamella elegans

In a survey of undiscovered taxa in Korea, three zygomycete fungal strains–EML-W31, EML-HGD1-1, and EML-RUS1-1–were isolated from freshwater, grasshopper fecal, and soil samples in Korea. On the basis of the morphological characteristics and phylogenetic analysis of internal transcribed spacer and 28S rDNA, the isolates of EML-W31, EML-HGD1-1, and EML-RUS1-1 were confirmed to be Cunninghamella bertholletiae, Cunninghamella echinulata, and Cunninghamella elegans, respectively. These species have not been previously described in Korea.

Phylogenetic Status of Two Undescribed Zygomycete Species from Korea: Actinomucor elegans and Mucor minutus

During a survey of fungal diversity of the order Mucorales, three zygomycete isolates, CNUFC-YR113-1, CNUFC-KNU16-7, and CNUFC-BS1-1 were isolated from freshwater and soil samples in Korea. The strains were analyzed both morphologically and phylogenetically based on internal transcribed spacer and 28S rDNA gene sequences. Based on their morphology and phylogeny, the CNUFC-YR113-1 and CNUFC-KNU16-7 isolates were identified as Actinomucor elegans, and CNUFC-BS1-1 was identified as Mucor minutus. To the best of our knowledge, the species A. elegans and M. minutus, belonging to an undiscovered taxon, have not been previously described in Korea.

Characterization of Two Species of Acremonium (Unrecorded in Korea) from Soil Samples: A. variecolor and A. persicinum

During a survey of fungal diversity of the order Hypocreales in Korea, two Acremonium isolates, CNUFC-1YSRS2-4 and CNUFC-GSNPF3-1, were isolated from soils collected on a bank of the Yeongsan River, Naju, and in a forest on the Mt. Daegak located on Sinsi Island, Gunsan, South Korea, respectively. Based on the morphological characteristics and sequence analysis of the internal transcribed spacer and D1/D2 domains of 28S ribosomal DNA, the isolates CNUFC-1YSRS2-4 and CNUFC-GSNPF3-1 were identified as A. variecolor and A. persicinum, respectively. These 2 species represent novel Hypocreales isolates in Korea.