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Diversity of thermophilic fungi from the Sevilleta. These are majority rule consensus trees derived from bootstrap (1000 replicates) parsimony analysis of ribosomal ITS sequences. Each of the isolates from this study (designated ThNM) fell into one of two orders within the Ascomycota, either Sordariales (A) or Eurotiales (B). Among the New Mexico isolates are strains closely related to known thermophilic species, including the two thermophilic members of the Chaetomiaceae for which complete genome sequences have been obtained (T. terrestris and M. thermophila). The Sordariales tree was rooted with Neurospora discreta. The Eurotiales tree was midpoint rooted. For CBS strains 202.75 and 203.75, we use the name Myceliophthora heterothallica, recently suggested by van den Brink et al. (2012). This species originally was described as Thielavia heterothallica (von Klopotek 1976).
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We report a comprehensive multi-year study of thermophilic fungi at the Sevilleta National Wildlife Refuge in central New Mexico. Recovery of thermophilic fungi from soils showed seasonal fluctuations, with greater abundance correlating with spring and summer precipitation peaks. In addition to grassland soils, we obtained and characterized isolate...
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Elucidation of fungal biomass degradation is important for understanding the turnover of biological materials in nature and has important implications for industrial biomass conversion. In recent years there has been an increasing interest in elucidating the biological role of thermophilic fungi and in characterization of their industrially useful...
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... For each sampling point, 1 L of fluid was taken in sterile bottles and conserved at 4°C until use. To selectively enrich for fungi, the Emerson YpSs Broth, ½ strength was used (ATCCÒ Medium 2370 (ATCCÒ, USA) [23]) supplemented with 50 mg/L of ampicillin [24]. This medium was used in the past to isolate thermophilic fungi from corn grains [25]. ...
Progresses in geothermal energy and deep drilling technologies have opened a new window into the terrestrial subsurface. This provides direct access to deep geothermal fluids used to produce heat and electricity, creating an opportunity to isolate and characterize novel microbial strains from these extreme habitats. In this study, we report the co-isolation of two fungal strains. Penicillium citrinum (strain HEK1) was isolated first and thought to be axenic. However, upon exposure to stress (frost and ethanol), a second strain, corresponding to the dimorphic yeast Meyerozyma guilliermondii (strain HEK2), appeared in HEK1 cultures. Strain HEK2 appeared first in the cultures and was followed by the subsequent re-growth of strain HEK1, underscoring their close relationship. Moreover, strain HEK2, able to switch from yeast cells to pseudohyphae when growing alone, did not produce pseudohyphae when in direct contact with strain HEK1. Altogether, our results indicate an intricate interaction between these strains that may allow them to thrive in the deep subsurface. These two fungi represent the first fungal strains isolated from deep geothermal fluids. Their presence within the fluids was confirmed through molecular analysis. The isolation of these strains emphasizes the importance of considering fungi when investigating microbial diversity in subsurface geothermal environments.
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Highlights
First fungal strains isolated from a geothermal power plant
The two fungal strains were co-isolated from a geothermal fluid used for heat production
Surprising isolation of the cell-switching yeast upon stress exposure of an apparently axenic culture of the filamentous fungus
Fungal strains with high resistance to stressors and no apparent competition for carbon sources
... These locales were predominantly populated by Ascomycota genera . Similar trends were observed by Huang et al., (2023), Liu et al., (2023), Morgenstern et al., (2012), andPowell et al., (2012), highlighting Ascomycota and Basidiomycota as prevalent phyla (Morgenstern et al., 2012;Powell et al., 2012;Huang et al., 2023;Liu et al., 2023). A study by Salano et al., (2017) in Kenya also noted Ascomycota and Basidiomycota as dominant in hot spring fungal communities, suggesting their adaptation to high temperatures (Salano et al., 2017). ...
... These locales were predominantly populated by Ascomycota genera . Similar trends were observed by Huang et al., (2023), Liu et al., (2023), Morgenstern et al., (2012), andPowell et al., (2012), highlighting Ascomycota and Basidiomycota as prevalent phyla (Morgenstern et al., 2012;Powell et al., 2012;Huang et al., 2023;Liu et al., 2023). A study by Salano et al., (2017) in Kenya also noted Ascomycota and Basidiomycota as dominant in hot spring fungal communities, suggesting their adaptation to high temperatures (Salano et al., 2017). ...
Temperature is a critical abiotic factor which determines the microbial diversity in several spheres of earth. Based on the microbial preference for their optimal range of temperature, microorganisms are classified in thermophiles, mesophiles and psychrophiles. However, in an environmental niche with gradient temperature i.e., across hot via warm to cold temperate region with other similar abiotic factors like pH and elemental compositions etc., how the microbial diversity changes with respect to temperature is largely unknown? Similarly, the abundance of various types of temperature-dependent bacteria like thermophiles, thermotolerant, mesophiles, psychro-tolerant and psychrophilic bacteria in a wide range of thermal gradient having antibiotic resistance and ARGs are also unknown. Here in this study, we have found that only specific bacteria tolerant to specific temperature grows optimally in their respective micro-environments. However, there were some commonly shared microbial communities among the mesophiles and psychrophiles but they did not contribute to bacterial abundance. Metagenomic analysis shows the prevalence of Pseudomonadota (Proteobacteria), Bacillota (Firmicutes), Bacteroidota (Bacteroidetes) and these phyla showed a linear increase or decrease in their abundance with respect to temperature. Temperature was the governing factor in shaping the bacterial diversity that was statistically significant by regression models in these microenvironments. Other factors such as pH and various elements, possessed insignificant effect on bacterial diversity. The abundance of mesophilic ARGs were predominant in the distinct thermal microenvironments which suggested that the antibiotic resistance was conferred by mesophiles at large and very few psychrophiles might also play a role in it. Presence of gyrase genes showcased the adaptability of the thermophilic bacteria across the thermal gradients. However, the minimal percentage of reverse gyrase also confirmed that the hot regions were devoid of any hyper-thermophilic microbes. Thermophilic bacteria were found to be devoid of antibiotic resistance. Regression analysis showed the inverse correlation of temperature with antibiotic resistance, i.e., antibiotic resistance decreases with increase in temperature. Antibiotic resistance is maximum at moderate temperatures and usually decreases with the increase and decrease in temperature from the optimum. These studies were carried out in pristine ecosystems with less anthropogenic activities. However, these decisive arguments could be also highlighted by further studying such environments. Furthermore, there is a great scope to perform such studies in contaminated environments that habits such thermal gradients.
... However, the Chytridiomycota, Glomeromycota, and Zygomycota groups made up only a meagre fraction of the total communities (Liu et al., 2018). This trend was not isolated to Liu et al.'s research, as similar findings were reported in the works of Mouchacca (1997), Morgenstern et al. (2012), andPowell et al. (2012), all of which showcased Ascomycota and Basidiomycota as the most prevalent phyla (Mouchacca, 1997;Morgenstern et al., 2012;Powell et al., 2012). A recent investigation by Salano et al. (2017) in Kenya also noted that Ascomycota and Basidiomycota dominated the fungal communities in hot springs, pointing to the possibility that these two groups harbour genuine thermophilic communities that can withstand high temperatures (Salano et al., 2017). ...
... However, the Chytridiomycota, Glomeromycota, and Zygomycota groups made up only a meagre fraction of the total communities (Liu et al., 2018). This trend was not isolated to Liu et al.'s research, as similar findings were reported in the works of Mouchacca (1997), Morgenstern et al. (2012), andPowell et al. (2012), all of which showcased Ascomycota and Basidiomycota as the most prevalent phyla (Mouchacca, 1997;Morgenstern et al., 2012;Powell et al., 2012). A recent investigation by Salano et al. (2017) in Kenya also noted that Ascomycota and Basidiomycota dominated the fungal communities in hot springs, pointing to the possibility that these two groups harbour genuine thermophilic communities that can withstand high temperatures (Salano et al., 2017). ...
Hot springs are like nature’s spas, which include warm and humid aquatic habitats that serve as a sanctuary for a diverse range of microorganisms, including bacteria, archaea, viruses, and eukaryotes fungi. Among these, fungi are one of the most important microorganisms, carrying out essential functions that often go unnoticed but are crucial in accelerating biological processes. These organisms have adapted to survive under a wide range of thermal conditions. While thermophilic fungi can withstand the scorching heat of deserts and hyper-saline conditions, other variants like mesophilic and psychrophilic fungi prefer more moderate and colder temperatures, respectively. The study employs shotgun metagenomic sequencing to obtain a fine-grained taxonomic classification of lesser-known species and microbial eukaryotes. This study aims to explore the relationship between fungal diversity and temperature in three distinct thermal zones; thermophilic (hot spring), mesophilic (plain field), and psychrophilic (semi-frigid zone) zones. The findings of our study demonstrated that there is a notable and positive association between the diversity of fungi and temperature, suggesting that temperature is a key factor in moulding fungal communities. However, it is important to note that further research is necessary to elucidate the underlying causal mechanisms of this relationship. Overall, our study adds to the knowledge of how environmental factors influence microbial diversity and can aid in the development of strategies for the conservation and management of fungal communities. Fungi are essential for many industrial applications, and their role in causing illnesses is also significant, making this research valuable for both scientific and practical purposes.
... Thermophily evolved independently multiple times across the fungal tree of life [10] and a few species are able to withstand temperatures up to ~ 60 °C [11]. Thermophilic fungi have been found in different habitats responding to a range of different environmental pressures and can also occur outside of thermal areas [12]. Additionally, fungi are well known to withstand other extreme abiotic factors including broad pH ranges, especially mycorrhizal fungi have been found to be sensitive to pH [13,14]. ...
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.
... Species of Thermomyces, Chaetomium, and Mycothermus are the most exist genera in different environments. Among them, Thermomyces lanuginosus and Mycothermus thermophilus are found as the most abundant (Powell et al. 2012). Curvularia protuberata from Dichanthelium lanuginosum is isolated from geothermal soils at temperature ranging between 38 and 65 ° of Lassen Volcanic and Yellowstone National Parks (Ali et al. 2018). ...
Fungi display an extraordinary level of structural and functional diversity with an estimated 1.5–5.1 million extant species. But, only 100,000 fungal species have so far been described. Fungi are one of the most important groups of eukaryotic organisms that are exploited for metabolites of potential therapeutic value as well as applications in diverse industries; by the way, fungal metabolites have a long history of both adverse and beneficial effects. Fungal biomolecules are an indispensable tool planned to accelerate the pace of the current research regarding the diverse roles of fungal biomolecules. The chapter encompasses a wide range of topics related to biomolecules synthesized and secreted by various fungal ecological groups useful in industrial, pharmaceutical, agricultural, and biotechnology sectors. Topics related to fungal enzymes have highlighted the significance of such enzymes in textile industries and environmental cleanup programs through the absorption of toxic heavy metals from soil, sludge, and industrial wastes.
... For instance, plant compost, herbivore dung, municipal waste, bird nests, wood chip piles (Korniłłowicz-Kowalska and Kitowski 2013;Ahirwar et al. 2017;Noreen et al. 2019), as well as fermenting foods are known habitats for thermophilous fungi (Zhang et al. 2016). Furthermore, the detection of thermophilous fungi in various types of soil has been often reported (Eggins and Malik 1969;Powell et al. 2012;Ahirwar et al. 2017). As a result of the unstable temperatures, the occurrence of mesophilic fungi, including heatresistant species, is common in these habitats. ...
... Thermophilous fungi have specific physiological and ecological requirements; however, different species in this group display different adaptations to temperature ranges and carbon sources (Powell et al. 2012;Morgenstern et al. 2012;Thanh et al. 2019). This diversity allows thermophilous fungi to colonize several niches and sub-habitats (Ahirwar et al. 2017;Salar 2018). ...
Thermophilic, thermotolerant and heat-resistant fungi developed different physiological traits, enabling them to sustain or even flourish under elevated temperatures, which are life-hostile for most other eukaryotes. With the growing demand of heat-stable molecules in biotechnology and industry, the awareness of heat-adapted fungi as a promising source of respective enzymes and biomolecules is still increasing. The aim of this study was to test two different strategies for the efficient isolation and identification of distinctly heat-adapted fungi from easily accessible substrates and locations. Eight compost piles and ten soil sites were sampled in combination with different culture-dependent approaches to describe suitable strategies for the isolation and selection of thermophilous fungi. Additionally, an approach with a heat-shock treatment, but without elevated temperature incubation led to the isolation of heat-resistant mesophilic species. The cultures were identified based on morphology, DNA barcodes, and microsatellite fingerprinting. In total, 191 obtained isolates were assigned to 31 fungal species, from which half are truly thermophilic or thermotolerant, while the other half are heat-resistant fungi. A numerous amount of heat-adapted fungi was isolated from both compost and soil samples, indicating the suitability of the used approaches and that the richness and availability of those organisms in such environments are substantially high.
... Maheshwari et al. (2000) proposed a new classification, in which thermophilic fungi are defined as those species with an optimum growth temperature of 45 °C or above. Thermophilic fungi were reported in a variety of environments, such as in composting systems (Kane and Mullins 1973;Straatsma et al. 1994), pond sediments (Ellis 1980), and different soil types (Pan et al. 2010;Powell et al. 2012). However, soil represents an important source of heat-resistant fungi (Jesenskfá et al. 1993). ...
We surveyed the diversity of cultivable fungi isolated from cold and hot volcanic soils of Deception Island, Antarctica. Seventy-four fungal isolates were identified; these belonged to 17 taxa in the genera Aspergillus, Penicillium, Pseudogymnoascus, Purpureocillium, and Mortierella. The fungal assemblages showed low diversity, richness, and dominance indices. The Aspergillus taxa were dominant in the soils at 0 °C, 50 °C, and 100 °C. Aspergillus lacticoffeatus, Aspergillus cf. ruber, Penicillium citrinun, and Purpureocillium sodanum were present only in soils having a temperature of 100 °C. Aspergillus calidoustus was present in all thermal soils and displayed the highest densities. The majority of fungi displayed mesophilic behavior; however, different isolates of Aspergillus lacticoffeatus and Aspergillus niger were able to grow at 50 °C; these are phylogenetically close to the causative agents of aspergillosis in immunocompromised individuals. Deception Island perhaps represents one of the most visited regions in Antarctica and the tourism there has increased over the last 20 years, especially by elderly tourists, probably with weak immune systems, come in contact with the resident microorganisms, including the thermo-resistant opportunistic Aspergillus species.
... The comprehensive study of the physiology and systematics of these organisms, however, did not begin until the Second World War (Emerson 1968). Although multiple definitions have been employed for fungal thermophiles, one working definition is that thermophilic fungi are those that grow better at 45 C than at 25 C (Powell et al. 2012). Although this definition is somewhat arbitrary, it can be used to distinguish between thermophilic and thermotolerant fungi: both have the ability to grow at 45 C or above but thermotolerant fungi grow better at lower temperatures (Cooney and Emerson 1964). ...
... The early studies of thermophilic fungi focused on compost (Miehe 1907;Emerson 1968), but it is now clear that they inhabit diverse ecosystems and can be isolated from a wide variety of substrates. They have been found in arid ecosystems (Powell et al. 2012), waterlogged grasslands, aquatic sediments, and the dung of birds and mammals (Singh et al. 2003). The ubiquitous nature of thermophilic fungi may be the result of both spore dispersal and their ability to degrade a wide array of organic materials (Salar and Aneja 2007). ...
... Sequences from this study are shown in bold. Sequences designated with "ThNM" numbers are from a previous study of thermophiles obtained from an arid grassland in New Mexico (Powell et al. 2012). GenBank numbers for sequences used for comparison are shown in parentheses. ...
Corn bins in the midwestern United States can reach temperatures up to 52 C. High temperatures combined with sufficient moisture and humidity in bins provide the perfect environment to promote the growth of thermophilic and thermotolerant fungi. In this article, we characterize for the first time thermophilic and thermotolerant fungi in corn grain bins using culture-based methods and pyrosequencing techniques. Corn samples were collected from local farms in western Illinois. Samples were plated and incubated at 50 C using a variety of approaches. Of several hundred kernels examined, more than 90% showed colonization. Species identified using culture methods included Thermomyces lanuginosus, Thermomyces dupontii, Aspergillus fumigatus, Thermoascus crustaceus, and Rhizomucor pusillus. Pyrosequencing was also performed directly on corn grain using fungal-specific primers to determine whether thermophilic fungi could be detected using this technique. Sequences were dominated by pathogenic fungi, and thermophiles were represented by less than 2% of the sequences despite being isolated from 90% of the grain samples using culturing techniques. The high abundance of previously undocumented viable fungi in corn could have negative implications for grain quality and pose a potential risk for workers and consumers of corn-derived products in the food industry. Members of the Sordariales were absent among thermophile isolates and were not represented in nuc rDNA internal transcribed spacer (ITS) sequences. This is in striking contrast with results obtained with other substrates such as litter, dung, and soils, where mesophilic and thermophilic members of the Sordariaceae and Chaetomiaceae are common. This absence appears to reflect an important difference between the ecology of Sordariales and other orders within the Ascomycota in terms of their ability to compete in microhabitats rich in sugars and living tissues.
... Thermotolerant communities were dominated by A. fumigatus; A. niger was the second most abundant Aspergillus species prevailing in the winter thermotolerant communities at Wadi Shaharut (Grishkan 2018). A. fumigatus is known as one of the most frequent and abundant thermotolerant species in a variety of desert regions (e.g., Abdullah et al. 1986;Bokhary 1998;Christensen 1981;Halwagy et al. 1982;Mouchacca 1993;Oliveira et al. 2013;Powell et al. 2012;Ranzoni 1968). This species also dominated microfungal communities isolated at 45 °C from the soil of the Arava Valley. ...
This chapter presents the results of mycological studies conducted in the soils of Israeli deserts covering more than 60% of the country, with annual rainfall ranging from more than 300 mm in the northwest to about 25 mm in the extreme south. In spite of hostility, the desert soils maintained a comparatively rich culturable fungal diversity—more than 420 species. This diversity has displayed remarkable adaptive strategies to harsh desert stresses reflected in diverse phenotypic and biological traits: (a) melanin-containing fungi with large, thick-walled, and multicellular conidia dominated the majority of topsoil communities and lost their dominant position either to the species with picnidial fruit bodies in the less UV-radiated area located 190 m below sea level or to thermophilic Aspergillus fumigatus in the extremely hot localities; (b) melanized species with protective spore morphology prevailed also in the deep layers of bare playa profiles characterized by high salinity and strongly limited water infiltration; (c) mesic Penicillium spp. dominated in the middle depths of sandy and playa profiles due to the ability of their abundantly produced small spores to penetrate during water infiltration; (d) aspergilli (mainly A. fumigatus) and sexual ascomycetes with perithecial fruit bodies comprised a basic part of thermotolerant mycobiota; (e) in most hostile environments, the structure of microfungal communities was subjected to relatively small spatiotemporal variations, while the density of fungal isolates fluctuated drastically, with highly positive dependence on organic matter content; and (f) distinct genetic structure and mode of reproduction characterized the population of A. nidulans from southern Negev.
... Fungi play an important role in this system; their exothermic metabolism raises the nest temperature to approximately 45 °C, similar to the heating process in natural composting (Seymour and Bradford 1992;Tiquia et al. 1996Tiquia et al. , 2002Tiquia 2005). In contraposition, some authors suggested that thermophily arose as an adaptation to seasonal changes and high daytime temperatures rather than as an adaptation for the occupation of new high-temperature niches (Powell et al. 2012). ...
... Among them, Thermomyces lanuginosus and Mycothermus thermophilus (syn. S. thermophilum) are not only present but also often found as the most abundant (Pan et al. 2010;Powell et al. 2012;De Gannes et al. 2013;Langarica-Fuentes et al. 2014a, b, 2015Oliveira et al. 2016). On the other hand, some species have not been recorded since they were identified for the first time, such as the Basidiomycota G. colossus. ...
One of the most fascinating properties of microorganisms is their ability to adapt to extreme environments. While several extremes of physical and chemical factors may drive particular communities, temperature plays a major influence on the functions of biomolecules and the maintenance of their biological structures. The maximum temperature limit for eukaryotes has been recorded as 62 °C, and only a few species of the kingdom Fungi are known to be truly thermophilic. Although distributed in taxonomically distinct lineages, thermophilic fungi constitute an ecologically well-defined group. In this review, we list 46 thermophilic fungal species belonging to 23 genera. There are representatives from the phyla Mucoromycota, Ascomycota, and Basidiomycota. Thermophilic fungi are common in habitats wherever organic matter decomposition takes place, leading to self-heating environments. Although thermophilic fungi have a great interest in biotechnology, knowledge of their ecology is still not clear. However, using the expertise from the applied perspective, one could perceive the roles of these fungi in nature. Here, we discuss the various concepts of thermophilic fungi and how they developed through time in the literature, their classification, biology, biogeography, putative ecological roles, and mechanisms for adaptations to thermophily.
