Culturable Fungi from Urban Soils in China I: Description of 10 New Taxa

Keratinophilic fungi are a group that can degrade and utilize keratin-rich material. It is also because of this ability that many taxa can cause infections in animals or humans but remain poorly studied.

Culturable fungi associated with the marine shallow-water hydrothermal vent crab Xenograpsus testudinatus at Kueishan Island, Taiwan

Reports on fungi occurring on marine crabs have been mostly related to those causing infections/diseases. To better understand the potential role(s) of fungi associated with marine crabs, this study investigated the culturable diversity of fungi on carapace of the marine shallow-water hydrothermal vent crab Xenograpsus testudinatus collected at Kueishan Island, Taiwan. By sequencing the internal transcribed spacer regions (ITS), 18S and 28S of the rDNA for identification, 12 species of fungi were isolated from 46 individuals of X. testudinatus: Aspergillus penicillioides, Aspergillus versicolor, Candida parapsilosis, Cladosporium cladosporioides, Mycosphaerella sp., Parengyodontium album, Penicillium citrinum, Penicillium paxili, Stachylidium bicolor, Zasmidium sp. (Ascomycota), Cystobasidium calyptogenae and Earliella scabrosa (Basidiomycota). With additional data from other published reports, a total of 26 species of fungi (23 Ascomycota, three Basidiomycota) have been recorded from X. testudinatus. Aspergillus is the most speciose genus on the crab, followed by Penicillium and Candida. All but one species (Xylaria arbuscula) had been previously isolated from substrates in the marine environment, although many are typical terrestrial taxa. None of the recorded fungi on X. testudinatus are reported pathogens of crabs, but some have caused diseases of other marine animals. Whether the crab X. testudinatus is a vehicle of marine fungal diseases requires further study.

Fungal Diversity of Selected Habitat Specific Cynorkis Species (Orchidaceae) in the Central Highlands of Madagascar

About 90% of Cynorkis species are endemic to the biodiversity hotspot of Madagascar. This terrestrial habitat-specific genus received little study for fungal diversity to support conservation. We evaluated the diversity of culturable fungi of 11 species and soil characteristics from six sites spanning a >40 km radius in and along the region’s inselbergs. Peloton-forming fungi were grown in vitro from root/protocorm slices and positively identified using DNA sequencing. The fungal diversity was then correlated with soil pH, NO3-N, P, and K. All species harbored either putative mycorrhizal associates in the Rhizoctonia complex or Hypocreales fungi. Tulasnella Operational Taxonomic Units (OTUs) were most prevalent in all soil types while Serendipita OTUs were found in species inhabiting granite/rock outcrops in moist soil (seepage areas). Most Cynorkis species were present in soil with low NO3-N and P levels with diversity of mycorrhizal fungi inversely correlated to NO3-N levels. Of the different orchid life stages sampled, only one species (Cynorkis fastigiata) yielded putative mycorrhizal fungi from juvenile stages. As diversity of mycorrhizal fungi of Cynorkis spp. was negatively correlated with NO3-N, and majority of the studied taxa were found in soils with low NO3-N and P contents, reintroduction studies must include analysis of N and P in detail. For the first time, we showed that the assemblage of culturable fungi in the roots of habitat-specific species of Cynorkis (Orchidaceae) are intimately tied to specific soil characteristics.

Fungi from dead arthropods and bats of Gomantong Cave, northern Borneo, Sabah (Malaysia)

Borneo is a biodiversity and ecotourism hotspot, yet one of its least-studied ecosystems is their limestone caves. Not many studies have been conducted on the role fungi play in tropical cave ecosystems, and no fungal surveys have been conducted in the caves of Sabah, Malaysia. Here, we assess the mycofloral diversity on bat and arthropod cadavers in one of the most popular ecotourism destinations of northern Borneo, Gomantong caves. Opportunistic sampling of cadavers within the Semud Hitam chamber of Gomantong cave yielded nine dead arthropods and four dead bats. Twenty-four culturable fungi were isolated, of which 14 morphological taxonomic units (MTU) were observed. Twelve of the 14 MTUs underwent molecular characterization of the ITS gene region to confirm identification. All fungi were Ascomycetes except for one Basidiomycete isolate. Aspergillus spp. had the highest occurrence (45.8%), followed by Penicillium spp. (25.0%), and Fusarium sp. (12.5%). Ceratobasidium sp., Diaporthe sp., Pestalotiopsis sp., and Xylaria feejeensis were isolated once each. No more than one fungal taxon was isolated from each arthropod cadaver, and not all arthropods yielded culturable fungi. Bat cadavers yielded 14 out of 24 isolates (58.3%), with the highest occurrence of the fungi sampled from their skin. Our results corroborate that bats and arthropods play a role in fungal dispersion and introduction in the cave because their exteriors are likely to harbor fungi they are exposed to in the environment. We also conclude that cadavers are important substrates for fungal growth and proliferation, perpetuating the role of fungi as important decomposers in caves. This study provides a baseline of information of the mycobiome of Bornean caves for future bioprospecting and potential biotechnological applications.

Uncovering fungal community composition in natural habitat of Ophiocordyceps sinensis using high-throughput sequencing and culture-dependent approaches

Background The fungal communities inhabiting natural Ophiocordyceps sinensis play critical ecological roles in alpine meadow ecosystem, contribute to infect host insect, influence the occurrence of O. sinensis, and are repertoire of potential novel metabolites discovery. However, a comprehensive understanding of fungal communities of O. sinensis remain elusive. Therefore, the present study aimed to unravel fungal communities of natural O. sinensis using combination of high-throughput sequencing and culture-dependent approaches. Results A total of 280,519 high-quality sequences, belonging to 5 fungal phyla, 15 classes, 41 orders, 79 families, 112 genera, and 352 putative operational taxonomic units (OTUs) were obtained from natural O. sinensis using high-throughput sequencing. Among of which, 43 genera were identified in external mycelial cortices, Ophiocordyceps, Sebacinia and Archaeorhizomyces were predominant genera with the abundance of 95.86, 1.14, 0.85%, respectively. A total of 66 genera were identified from soil microhabitat, Inocybe, Archaeorhizomyces, unclassified Thelephoraceae, Tomentella, Thelephora, Sebacina, unclassified Ascomycota and unclassified fungi were predominant genera with an average abundance of 53.32, 8.69, 8.12, 8.12, 7.21, 4.6, 3.08 and 3.05%, respectively. The fungal communities in external mycelial cortices were significantly distinct from soil microhabitat. Meanwhile, seven types of culture media were used to isolate culturable fungi at 16 °C, resulted in 77 fungal strains identified by rDNA ITS sequence analysis, belonging to 33 genera, including Ophiocordyceps, Trichoderma, Cytospora, Truncatella, Dactylonectria, Isaria, Cephalosporium, Fusarium, Cosmospora and Paecilomyces, etc.. Among all culturable fungi, Mortierella and Trichoderma were predominant genera. Conclusions The significantly differences and overlap in fungal community structure between two approaches highlight that the integration of high-throughput sequencing and culture-dependent approaches would generate more information. Our result reveal a comprehensive understanding of fungal community structure of natural O. sinensis, provide new insight into O. sinensis associated fungi, and support that microbiota of natural O. sinensis is an untapped source for novel bioactive metabolites discovery.

Fruit host-dependent fungal communities in the microbiome of wild Queensland fruit fly larvae

Bactrocera tryoni (Froggatt), the Queensland fruit fly (Qfly), is a highly polyphagous tephritid fly that is widespread in Eastern Australia. Qfly physiology is closely linked with its fungal associates, with particular relationship between Qfly nutrition and yeast or yeast-like fungi. Despite animal-associated fungi typically occurring in multi-species communities, Qfly studies have predominately involved the culture and characterisation of single fungal isolates. Further, only two studies have investigated the fungal communities associated with Qfly, and both have used culture-dependant techniques that overlook non-culturable fungi and hence under-represent, and provide a biased interpretation of, the overall fungal community. In order to explore a potentially hidden fungal diversity and complexity within the Qfly mycobiome, we used culture-independent, high-throughput Illumina sequencing techniques to comprehensively, and holistically characterized the fungal community of Qfly larvae and overcome the culture bias. We collected larvae from a range of fruit hosts along the east coast of Australia, and all had a mycobiome dominated by ascomycetes. The most abundant fungal taxa belonged to the genera Pichia (43%), Candida (20%), Hanseniaspora (10%), Zygosaccharomyces (11%) and Penicillium (7%). We also characterized the fungal communities of fruit hosts, and found a strong degree of overlap between larvae and fruit host communities, suggesting that these communities are intimately inter-connected. Our data suggests that larval fungal communities are acquired from surrounding fruit flesh. It is likely that the physiological benefits of Qfly exposure to fungal communities is primarily due to consumption of these fungi, not through syntrophy/symbiosis between fungi and insect ‘host’.