Three new genera of fungi from extremely acidic soils

Extremely acidic soils (pH<3) harbour poorly diversified mycobiota that are very different from less acidic habitats. During investigations of the mycobiota from several highly acidic soils in the Czech Republic and a coastal site in the Antarctic Peninsula, a group of hyaline fungal isolates was obtained. Based on phenotype and nuclear ribosomal DNA sequences (ITS region, SSU, LSU), the isolates belonged to three phylogenetic lineages within two different classes, Sordariomycetes and Leotiomycetes (Pezizomycotina, Ascomycota). The first lineage is described here as a new genus and species Acidothrix acidophila gen. nov. et sp. nov. (Amplistromataceae, Sordariomycetes, Ascomycota). The most closely related species to this new clade are woodinhabiting fungi. The isolates belonging to the second and the third lineages are also described as two new genera and species Acidea extrema gen. nov. et sp. nov. and Soosiella minima gen. nov. et sp. nov. (Helotiales, Leotiomycetes, Ascomycota). Their position and the relationships within Helotiales are discussed. Soosiella minima was acidotolerant, Acidothrix acidophila and Acidea extrema exhibited both acidotolerant and acidophilic characteristics. All the species were slightly halophilic. The adaptation of hyaline fungi from mesophilic lineages to highly acidic environments has been revealed. The association between highly acidic and Antarctic habitats is discussed.http://link.springer.com/journal/11557hb201

Diversity and taxonomy of fungi inhabiting extremely acidic and saline soils of natural and anthropogenic origin in the Czech Republic

Highly acidic environments represent some of the most extreme habitats for the microbial growth. For a long time it has been assumed that these sites are populated exclusively by prokaryotes. However recently, eukaryotic organisms including fungi have been found to be abundant and important component of acidophilic communities. Concerning fungal diversity only fragmentary data are available indicating that highly acidic sites harbour specific and low-diversified fungal communities dominated by dematiaceous fungi. In the present work we focused on the cultivable mycobiota occupying highly acidic (pH < 3) soils which are at the same time saline (sulfate-rich) and are located at geographically isolated localities in the Czech Republic. This study should provide a deep insight into the diversity and biogeographical pattern of acidophilic/tolerant fungi. A combination of classical and specialized cultivation techniques was successfully applied since it significantly contributed to the broadening of the detected fungal spectrum. The revealed fungal assemblages inhabiting highly acidic sites worldwide are closely similar and differ from the ones known from less acidic habitats. The core of the fungal assemblage under study consisted of phylogenetically unrelated and often globally distributed fungi..

Diversity and taxonomy of fungi inhabiting extremely acidic and saline soils of natural and anthropogenic origin in the Czech Republic

Highly acidic environments represent some of the most extreme habitats for the microbial growth. For a long time it has been assumed that these sites are populated exclusively by prokaryotes. However recently, eukaryotic organisms including fungi have been found to be abundant and important component of acidophilic communities. Concerning fungal diversity only fragmentary data are available indicating that highly acidic sites harbour specific and low-diversified fungal communities dominated by dematiaceous fungi. In the present work we focused on the cultivable mycobiota occupying highly acidic (pH < 3) soils which are at the same time saline (sulfate-rich) and are located at geographically isolated localities in the Czech Republic. This study should provide a deep insight into the diversity and biogeographical pattern of acidophilic/tolerant fungi. A combination of classical and specialized cultivation techniques was successfully applied since it significantly contributed to the broadening of the detected fungal spectrum. The revealed fungal assemblages inhabiting highly acidic sites worldwide are closely similar and differ from the ones known from less acidic habitats. The core of the fungal assemblage under study consisted of phylogenetically unrelated and often globally distributed fungi..

Diverzita a taxonomie mikroskopických hub v extrémně kyselých zasolených půdách přirozeně vzniklých a antropogenních stanovišť v České republice

Silně kyselé substráty (pH < 3) představují pro život mikroorganismů jedno z nejextrémnějších prostředí. Dlouhou dobu panoval názor, že tento typ habitatu osidlují výhradně prokaryotní organismy. Nicméně výsledky recentních studií ukázaly, že mikrobiální společenstvo silně kyselých substrátů je tvořeno z velké části rovněž eukaryotickou složkou zahrnující vedle řas a protist také houby. O diverzitě acidofilních/tolerantních hub, je prozatím k dispozici jen málo informací, které ukazují, že zdejší houbové společenstvo je druhově chudé, specifické s převahou demáciových druhů. Předkládaná práce se zabývá studiem diverzity a taxonomie kultivovatelných druhů hub osidlujících silně kyselé a zároveň zasolené (sulfátové) půdy, a to na několika geograficky izolovaných lokalitách v rámci České republiky. Porovnání našich dat s dalšími dostupnými informacemi o houbách izolovaných z podobných silně kyselých míst ve světě umožní odhalit druhy tvořící základ zdejšího společenstva a jejich případnou podobnost, a zároveň pomohou objasnit otázku rozšíření acidofilních/tolerantních hub. S cílem rozšířit detekované houbové spektrum byla pro izolaci úspěšně použita kombinace standardně užívaných a speciálních metod. Naše výsledky ukázaly, že silně kyselé substráty po celém světě skrývají velmi podobné houbové...Highly acidic environments represent some of the most extreme habitats for the microbial growth. For a long time it has been assumed that these sites are populated exclusively by prokaryotes. However recently, eukaryotic organisms including fungi have been found to be abundant and important component of acidophilic communities. Concerning fungal diversity only fragmentary data are available indicating that highly acidic sites harbour specific and low-diversified fungal communities dominated by dematiaceous fungi. In the present work we focused on the cultivable mycobiota occupying highly acidic (pH < 3) soils which are at the same time saline (sulfate-rich) and are located at geographically isolated localities in the Czech Republic. This study should provide a deep insight into the diversity and biogeographical pattern of acidophilic/tolerant fungi. A combination of classical and specialized cultivation techniques was successfully applied since it significantly contributed to the broadening of the detected fungal spectrum. The revealed fungal assemblages inhabiting highly acidic sites worldwide are closely similar and differ from the ones known from less acidic habitats. The core of the fungal assemblage under study consisted of phylogenetically unrelated and often globally distributed fungi...Department of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Saprotrophic soil micromycetes in extreme sites (on the example of National Natural Reserve "SOOS", Czech Rebublic)

Katedra botanikyDepartment of BotanyPřírodovědecká fakultaFaculty of Scienc

Correlative evidence for co-regulation of phosphorus and carbon exchanges with symbiotic fungus in the arbuscular mycorrhizal Medicago truncatula.

Research efforts directed to elucidation of mechanisms behind trading of resources between the partners in the arbuscular mycorrhizal (AM) symbiosis have seen a considerable progress in the recent years. Yet, despite of the recent developments, some key questions still remain unanswered. For example, it is well established that the strictly biotrophic AM fungus releases phosphorus to- and receives carbon molecules from the plant symbiont, but the particular genes, and their products, responsible for facilitating this exchange, are still not fully described, nor are the principles and pathways of their regulation. Here, we made a de novo quest for genes involved in carbon transfer from the plant to the fungus using genome-wide gene expression array targeting whole root and whole shoot gene expression profiles of mycorrhizal and non-mycorrhizal Medicago truncatula plants grown in a glasshouse. Using physiological intervention of heavy shading (90% incoming light removed) and the correlation of expression levels of MtPT4, the mycorrhiza-inducible phosphate transporter operating at the symbiotic interface between the root cortical cells and the AM fungus, and our candidate genes, we demonstrate that several novel genes may be involved in resource tradings in the AM symbiosis established by M. truncatula. These include glucose-6-phosphate/phosphate translocator, polyol/monosaccharide transporter, DUR3-like, nucleotide-diphospho-sugar transferase or a putative membrane transporter. Besides, we also examined the expression of other M. truncatula phosphate transporters (MtPT1-3, MtPT5-6) to gain further insights in the balance between the "direct" and the "mycorrhizal" phosphate uptake pathways upon colonization of roots by the AM fungus, as affected by short-term carbon/energy deprivation. In addition, the role of the novel candidate genes in plant cell metabolism is discussed based on available literature

Little Cross-Feeding of the Mycorrhizal Networks Shared Between C3-Panicum bisulcatum and C4-Panicum maximum Under Different Temperature Regimes

Common mycorrhizal networks (CMNs) formed by arbuscular mycorrhizal fungi (AMF) interconnect plants of the same and/or different species, redistributing nutrients and draining carbon (C) from the different plant partners at different rates. Here, we conducted a plant co-existence (intercropping) experiment testing the role of AMF in resource sharing and exploitation by simplified plant communities composed of two congeneric grass species (Panicum spp.) with different photosynthetic metabolism types (C3 or C4). The grasses had spatially separated rooting zones, conjoined through a root-free (but AMF-accessible) zone added with 15N-labeled plant (clover) residues. The plants were grown under two different temperature regimes: high temperature (36/32°C day/night) or ambient temperature (25/21°C day/night) applied over 49 days after an initial period of 26 days at ambient temperature. We made use of the distinct C-isotopic composition of the two plant species sharing the same CMN (composed of a synthetic AMF community of five fungal genera) to estimate if the CMN was or was not fed preferentially under the specific environmental conditions by one or the other plant species. Using the C-isotopic composition of AMF-specific fatty acid (C16:1ω5) in roots and in the potting substrate harboring the extraradical AMF hyphae, we found that the C3-Panicum continued feeding the CMN at both temperatures with a significant and invariable share of C resources. This was surprising because the growth of the C3 plants was more susceptible to high temperature than that of the C4 plants and the C3-Panicum alone suppressed abundance of the AMF (particularly Funneliformis sp.) in its roots due to the elevated temperature. Moreover, elevated temperature induced a shift in competition for nitrogen between the two plant species in favor of the C4-Panicum, as demonstrated by significantly lower 15N yields of the C3-Panicum but higher 15N yields of the C4-Panicum at elevated as compared to ambient temperature. Although the development of CMN (particularly of the dominant Rhizophagus and Funneliformis spp.) was somewhat reduced under high temperature, plant P uptake benefits due to AMF inoculation remained well visible under both temperature regimes, though without imminent impact on plant biomass production that actually decreased due to inoculation with AMF

Mutabilis in mutabili: Spatiotemporal dynamics of a truffle colony in soil

The functioning of ectomycorrhizal (ECM) symbioses is closely related to the development of the soil mycelial phase the ECM fungi. The properties and spatiotemporal dynamics of such mycelia in ecosystems is, however, poorly understood. Here we show, using a soil colony of summer truffle (Tuber aestivum) as a model, that an ECM mycelium may only grow and colonize newly-opened soil patches when soil temperatures rise above certain threshold, in this case +10 °C, provided other requirements such as sufficient soil moisture are fulfilled. Extension rates of truffle mycelium in the fields was recorded as >0.3 μm min−1, several-fold greater than that predicted from laboratory cultures. Further, we demonstrated that there was a consistent spatial differentiation in mycelium growth patterns within the fungal colony on a decimeter scale, changing from “diffusion” type of growth at the colony margin to “colony-front” pattern further away from the colony margin. This change was clearly accompanied by shifting structure of soil microbial communities with Terrimonas sp. and another unidentified bacterium correlating with the “colony-front” mycelium growth pattern, and Sphingomonas sp. and Lysobacter brunnescens with the “diffusion” type of mycelium growth. Possible implications of the observed truffle colony differentiation are discussed for processes like fruit-body formation and dispersal of this ECM fungus. Our data indicate that the thallus of T. aestivum has to be considered as a principally variable (“mutabilis”) being in space and time, whose behavior correlates with conditions in ever changing soil environment (“in mutabili”)