Fungal Community Shift Along Steep Environmental Gradients from Geothermal Soils in Yellowstone National Park.

Geothermal soils offer unique insight into the way extreme environmental factors shape communities of organisms. However, little is known about the fungi growing in these environments and in particular how localized steep abiotic gradients affect fungal diversity. We used metabarcoding to characterize soil fungi surrounding a hot spring-fed thermal creek with water up to 84 °C and pH 10 in Yellowstone National Park. We found a significant association between fungal communities and soil variable principal components, and we identify the key trends in co-varying soil variables that explain the variation in fungal community. Saprotrophic and ectomycorrhizal fungi community profiles followed, and were significantly associated with, different soil variable principal components, highlighting potential differences in the factors that structure these different fungal trophic guilds. In addition, in vitro growth experiments in four target fungal species revealed a wide range of tolerances to pH levels but not to heat. Overall, our results documenting turnover in fungal species within a few hundred meters suggest many co-varying environmental factors structure the diverse fungal communities found in the soils of Yellowstone National Park.

First Genome of Labyrinthula sp., an Opportunistic Seagrass Pathogen, Reveals Novel Insight into Marine Protist Phylogeny, Ecology and CAZyme Cell-Wall Degradation.

Labyrinthula spp. are saprobic, marine protists that also act as opportunistic pathogens and are the causative agents of seagrass wasting disease (SWD). Despite the threat of local- and large-scale SWD outbreaks, there are currently gaps in our understanding of the drivers of SWD, particularly surrounding Labyrinthula spp. virulence and ecology. Given these uncertainties, we investigated the Labyrinthula genus from a novel genomic perspective by presenting the first draft genome and predicted proteome of a pathogenic isolate Labyrinthula SR_Ha_C, generated from a hybrid assembly of Nanopore and Illumina sequences. Phylogenetic and cross-phyla comparisons revealed insights into the evolutionary history of Stramenopiles. Genome annotation showed evidence of glideosome-type machinery and an apicoplast protein typically found in protist pathogens and parasites. Proteins involved in Labyrinthula SR_Ha_C's actin-myosin mode of transport, as well as carbohydrate degradation were also prevalent. Further, CAZyme functional predictions revealed a repertoire of enzymes involved in breakdown of cell-wall and carbohydrate storage compounds common to seagrasses. The relatively low number of CAZymes annotated from the genome of Labyrinthula SR_Ha_C compared to other Labyrinthulea species may reflect the conservative annotation parameters, a specialized substrate affinity and the scarcity of characterized protist enzymes. Inherently, there is high probability for finding both unique and novel enzymes from Labyrinthula spp. This study provides resources for further exploration of Labyrinthula spp. ecology and evolution, and will hopefully be the catalyst for new hypothesis-driven SWD research revealing more details of molecular interactions between the Labyrinthula genus and its host substrate.

Two new species of the Fusarium fujikuroi species complex isolated from the natural environment.

Two new species in the Fusarium fujikuroi species complex (FFSC) are introduced. One of these, represented by strain CBS 454.97 was isolated from plant debris (Striga hermonthica) in the Sudan, while the second, represented by strains CBS 119850 and CBS 483.94, which originated from soil in Australia. Molecular analyses were performed including TEF1 spanning 576 bp region, 860 bp region of rPB2, and 500 bp BT2 region. Phylogenetic trees based on these regions showed that the two species are clearly distinct from all known taxa in the F. fujikuroi species complex. Based on phenotypic, physiological characters and molecular data, we introduce Fusarium sudanense and Fusarium terricola as novel species in the complex.

Diversity, morphology, and molecular phylogeny of Diatrypaceae from southern China.

During an investigation of Diatrypaceae from southern China, 10 xylariales-like taxa have been collected. Morphological and multi-gene analyses confirmed that these taxa reside in Diatrypaceae and represent eight novel taxa and two new records belonging to six genera (viz., Allocryptovalsa, Diatrype, Diatrypella, Paraeutypella, Peroneutypa, and Vasilyeva gen. nov.). Vasilyeva gen. nov. was proposed to accommodate Vasilyeva cinnamomi sp. nov. Among the other collections, seven new species were introduced (viz., Diatrype camelliae-japonicae sp. nov., Diatrype rubi sp. nov., Diatrypella guiyangensis sp. nov., Diatrypella fatsiae-japonicae sp. nov., Paraeutypella subguizhouensis sp. nov., Peroneutypa hainanensis sp. nov., and Peroneutypa qianensis sp. nov.), while two were reported as new records from China (Allocryptovalsa rabenhorstii and Diatrype enteroxantha). For Diatrypaceae, the traditional taxonomic approach based on morphology may not be applicable.

Fungal Species from Rhododendron sp.: Discosia rhododendricola sp.nov, Neopestalotiopsis rhododendricola sp.nov and Diaporthe nobilis as a New Host Record.

In the present study, we report two new asexual fungal species (i.e., Discosia rhododendricola, Neopestalotiopsis rhododendricola (Sporocadaceae) and a new host for a previously described species (i.e., Diaporthe nobilis; Diaporthaceae). All species were isolated from Rhododendron spp. in Kunming, Yunnan Province, China. All taxa are described based on morphology, and phylogenetic relationships were inferred using a multigenic approach (LSU, ITS, RPB2, TEF1 and TUB2). The phylogenetic analyses indicated that D. rhododendronicola sp. nov. is phylogenetically related to D. muscicola, and N. rhododendricola sp. nov is related to N. sonnaratae. Diaporthe nobilis is reported herein as a new host record from Rhododendron sp. for China, and its phylogeny is depicted based on ITS, TEF1 and TUB2 sequence data.

Polyrhizophydium stewartii, the first known rhizomycelial genus and species in the Rhizophydiales, is closely related to Batrachochytrium.

Molecular and ultrastructural investigations of the Chytridiomycota during the last 20 years have led to the separation of new orders, including the Rhizophydiales. Most species in this order are morphologically similar, possessing monocentric, eucarpic, spherical thalli. Here, based on analysis of nuc 18S and 28S rDNA, we add the new genus and species Polyrhizophydium stewartii to the order. This saprobe of moribund aquatic plant leaves is the first known rhizomycelial species in the order. In our molecular phylogeny, P. stewartii groups with the amphibian pathogens Batrachochytriuim dendrobatidis and B. salamandrivorans, making it of particular interest to investigators studying evolutionary pathways associated with host-switching and morphological adaptation.

Veronaeaaquatica sp. nov. (Herpotrichiellaceae, Chaetothyriales, Eurotiomycetes) from submerged bamboo in China.

BACKGROUND: Freshwater fungi are highly diverse and ecologically important in freshwater systems. In China, more than 1000 species of freshwater fungi are known. Here, we present a brown-spored hyphomycetes that was collected on a submerged decaying bamboo culm in a forest stream in China. NEW INFORMATION: Phylogenetic analyses of combined LSU, ITS and TUB2 sequences confirm the placement of our new strain in Veronaea (Herpotrichiellaceae), sister to V.japonica. Veronaeaaquatica sp. nov. differs from related taxa V.compacta and V.japonica in having longer conidiophores and cylindrical to pyriform or subclavate conidia with 0-2 septa. Veronaeaaquatica also has darker brown hyphae compared to V.japonica. A morphological description and detailed illustrations of V.aquatica are provided.

The Split Personality of Beauveria bassiana: Understanding the Molecular Basis of Fungal Parasitism and Mutualism.

Fungal pathogenicity toward insects has independently evolved several times, resulting in specialist and generalist pathogens, some of whom have maintained aspects of their previous lifestyles. Being able to grow as an endophyte (engaging in a mutualistic interaction with plants) or saprophyte (recycling nutrients back into the environment), the generalist (broad-host-range) fungus Beauveria bassiana does not need to rely on insect hosts to complete its life cycle. The diverse lifestyles of this fungus, saprophyte, pathogen, and symbiont, provide a unique system, with available genetic tools, to examine host-pathogen interactions, plant-fungus mutualistic relationships, and fungal development. This commentary highlights overlooked pathogenic and mutualistic aspects of B. bassiana that assist this fungus in shifting along the saprobe/parasite/mutualist continuum. Addressing these knowledge gaps and scrutinizing valuable players driving such a spectrum of ecological interactions will enrich our knowledge of fundamental environmental microbiology and help develop new approaches to pest control and sustainable farming.

Novel species of Pestalotiopsis fungi on Dracaena from Thailand.

A survey of the diversity and distribution of microfungi on Dracaena leaf litter in Songkhla Province (Thailand) yielded two collections of pestalotiopsis-like fungi. Analyses of a combined ITS, TEF1-α and TUB2 sequence data matrix were applied to infer the phylogenetic position of these new isolates in Pestalotiopsis. The phylogenies indicated that these two isolates were monophyletic and constituted a distinct lineage that perceived a taxonomic novelty in Pestalotiopsis. This clade shared a close phylogenetic affinity with P. adusta, P. krabiensis, P. pandanicola and P. papuana. The comparison of morphological features with the phylogenetically closely related taxa are given and the new species is introduced as Pestalotiopsis dracaenicola sp. nov. with comprehensive descriptions and illustrations herein.

Arbuscular mycorrhizal fungi alleviate oxidative stress induced by ADOR and enhance antioxidant responses of tomato plants.

The behaviour of tomato plants inoculated with arbuscular mycorrhizal (AM) fungi grown in the presence of aqueous extracts from dry olive residue (ADOR) was studied in order to understand how this symbiotic relationship helps plants to cope with oxidative stress caused by ADOR. The influence of AM symbiosis on plant growth and other physiological parameters was also studied. Tomato plants were inoculated with the AM fungus Funneliformis mosseae and were grown in the presence of ADOR bioremediated and non-bioremediated by Coriolopsis floccosa and Penicillium chrysogenum-10. The antioxidant response as well as parameters of oxidative damage were examined in roots and leaves. The data showed a significant increase in the biomass of AM plant growth in the presence of ADOR, regardless of whether it was bioremediated. The establishment and development of the symbiosis were negatively affected after plants were exposed to ADOR. No differences were observed in the relative water content (RWC) or PS II efficiency between non-AM and AM plants. The increase in the enzymatic activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione-S-transferase (GST; EC 2.5.1.18) were simultaneous to the reduction of MDA levels and H2O2 content in AM root growth in the presence of ADOR. Similar H2O2 levels were observed among non-AM and AM plants, although only AM plants showed reduced lipid peroxidation content, probably due to the involvement of antioxidant enzymes. The results highlight how the application of both bioremediated ADOR and AM fungi can alleviate the oxidative stress conditions, improving the growth and development of tomato plants.