Comparison of the diversity,composition, and host recurrence of xylariaceous endophytes in subtropical,cool temperate,and subboreal regions in Japan

The diversity, composition, and host recurrence of endophytic fungi in the Xylariaceae were compared in subtropical (ST), cool temperate (CT), and subboreal forests (SB) in Japan based on the 28S ribosomal DNA sequences from fungal isolates. A total of 610 isolates were obtained from the leaves of 167 tree species in three sites, which were classified into 42 operational taxonomic units (OTUs) at the 99 % similarity level of the 28S rDNA sequence. ST, CT, and SB yielded 31, 13, and three OTUs, respectively. The OTU richness, diversity, and evenness of fungal communities were in the order: ST > CT > SB. The 42 OTUs were assigned to nine genera in the Xylariaceae: Xylaria, Annulohypoxylon, Anthostomella, Biscogniauxia, Nemania, Hypoxylon, Muscodor, Daldinia, and Rosellinia. Xylarioid isolates in the subfamily Xylarioideae outnumbered Hypoxyloid isolates in the subfamily Hypoxyloideae in ST and CT, whereas the opposite was found in SB. Sørensen’s quotient of similarity was generally low between the three sites. Host recurrence of fungal OTUs was evaluated with the degree of specialization of interaction network between xylariaceous endophytes and plant species and compared between the three sites. We found that the networks in the three sites showed a significantly higher degree of specialization than simulated networks, where partners were associated randomly. Permutational multivariate analyses of variance indicated that plant family and leaf trait significantly affected the OTU composition in ST, which can account for the specialization of interaction network and host recurrence of xylariaceous endophytes.     

Diversity and dynamics of fungal endophytes in leaves, stems and roots of Stellera chamaejasme L. in northwestern China

This study was conducted to explore fungal endophyte communities inhabiting a toxic weed (Stellera chamaejasme L.) from meadows of northwestern China. The effects of plant tissue and growth stage on endophyte assemblages were characterized. Endophytes were recovered from 50 % of the samples, with a total of 714 isolates. 41 operational taxonomical units (OTUs) were identified, consisting of 40 OTUs belonging primarily to Ascomycota and 1 OTU belonging to Basidiomycota. Pleosporales and Hypocreales were the orders contributing the most species to the endophytic assemblages. The total colonization frequency and species richness of endophytic fungi were higher in roots than in leaves and stems. In addition, for the plant tissues, the structure of fungal communities differed significantly by growth stages of leaf emergence and dormancy; for the plant growth stages, the structure of fungal communities differed significantly by plant tissues. This study demonstrates that S. chamaejasme serves as a reservoir for a wide variety of fungal endophytes that can be isolated from various plant tissues.     

Fungal Endophytes of Aquatic Macrophytes: Diverse Host-Generalists Characterized by Tissue Preferences and Geographic Structure

Most studies of endophytic symbionts have focused on terrestrial plants, neglecting the ecologically and economically important plants present in aquatic ecosystems. We evaluated the diversity, composition, host and tissue affiliations, and geographic structure of fungal endophytes associated with common aquatic plants in lentic waters in northern Arizona, USA. Endophytes were isolated in culture from roots and photosynthetic tissues during two growing seasons. A total of 226 isolates representing 60 putative species was recovered from 9,600 plant tissue segments. Although isolation frequency was low, endophytes were phylogenetically diverse and species-rich. Comparisons among the most thoroughly sampled species and reservoirs revealed that isolation frequency and diversity did not differ significantly between collection periods, among species, among reservoirs, or as a function of depth. However, community structure differed significantly among reservoirs and tissue types. Phylogenetic analyses of a focal genus (Penicillium) corroborated estimates of species boundaries and informed community analyses, highlighting clade- and genotype-level affiliations of aquatic endophytes with both sediment- and waterborne fungi, and endophytes of proximate terrestrial plants. Together these analyses provide a first quantitative examination of endophytic associations in roots and foliage of aquatic plants and can be used to optimize survey strategies for efficiently capturing fungal biodiversity at local and regional scales.     

High diversity of root-associated fungi isolated from three epiphytic orchids in southern Ecuador

Knowledge of fungal root-associates is essential for effective conservation of tropical epiphytic orchids. We investigated the diversity of root-associated fungi of Cyrtochilum myanthum, Scaphyglottis punctulata and Stelis superbiens from a tropical mountain rainforest in southern Ecuador, using a culture dependent approach. We identified 115 fungal isolates, corresponding to 49 fungal OTUs, based on sequences of the nrDNA ITS and partial 28S region. Members of Ascomycota were unambiguously dominant (37 OTUs), including Trichoderma sp. as the most frequent taxon. Members of Basidiomycota (Agaricales and Polyporales) and Mucoromycota (Umbelopsidales and Mortierellales) were also identified. Four potential mycorrhizal OTUs of Tulasnellaceae and Ceratobasidiaceae were isolated from C. myanthum and S. superbiens. Fungal community composition was examined using Sørensen and Jaccard indices of similarity. Alfa diversity was significantly different between C. myanthum and S. superbiens. No difference in beta diversity of the fungal communities between the 3 orchid species and the collecting sites was detected. The study revealed a high diversity of fungi associated with orchid roots. Our results contribute to a better understanding of specific relationships between epiphytic orchids and their root-associated fungi.     

Culturable fungal endophytes in roots of Enkianthus campanulatus (Ericaceae)

Roots of plants in the genus Enkianthus, which belongs to the earliest diverging lineage in the Ericaceae, are commonly colonized by arbuscular mycorrhizal (AM) fungi. We documented the community of fungal root endophytes associated with Enkianthus species using a culture-based method for better understanding the members of root-colonizing fungi, except for AM fungi. Fungal isolates were successfully obtained from 610 out of 3,599 (16.9 %) root segments. Molecular analysis of fungal cultures based on ribosomal internal transcribed spacer (ITS) sequences yielded 63 operational taxonomical units (OTUs: 97 % sequence similarity cutoff) from 315 representative isolates. Further phylogenetic analysis showed that most (296 isolates) belonged to Ascomycota and were either members of Helotiales (Dermataceae, Hyaloscyphaceae, Phialocephala and Rhizoscyphus ericae aggregate), Oidiodendron, or other Pezizomycotina. Twenty-three out of 63 OTUs, which mainly consisted of Leotiomycetes, showed high similarities with reference sequences derived from roots of other ericaceous plants such as Rhododendron. The results indicated that Enkianthus houses variable root mycobionts including putative endophytic and mycorrhizal fungi in addition to AM fungi.     

Characteristics of endophytic fungi from Polygonum hydropiper suggest potential application for P-phytoextraction

Endophytes may play important roles in phytoremediation; however, little information is available on the endophytes of phosphorus (P)-accumulating plants and their potential application in P-phytoextraction. Here, 30 endophytic fungi were isolated from Polygonum hydropiper and classified into 24 taxonomic groups, with 76.7% being Ascomycota and 23.3% being Basidiomycota. Metarhizium anisopliae, Guignardia mangiferae and Phaeophlebiopsis peniophoroides were the dominant species. The Simpson and Shannon diversity indices were higher in shoots than in roots. The isolates had varied plant-growth-promoting traits with all being indole-3-acetic acid positive and only 18 exhibiting siderophore activities. P solubilization capability varied with fungal species and P sources; it correlated negatively with pH but positively with organic acids in a tricalcium phosphate medium. However, in a phytin medium, it did not correlate with pH, but positively with phosphatase activities. Five endophytes were found to have the greatest potential as inoculants to assist P. hydropiper in future P-phytoextraction studies.     

Diversity,Molecular Phylogeny,and Bioactive Potential of Fungal Endophytes Associated with the Himalayan Blue Pine (Pinus wallichiana)

In this study, we investigated the diversity of fungal endophytes associated with Pinus wallichiana from the Western Himalayas, with emphasis on comparison of endophytic communities harbored by the stem and needle tissues of the host and their antimicrobial potential. A total number of 130 isolates, comprising of 38 different genera, were recovered from 210 fragments of the plant. Among the isolated fungi, only a single isolate, Tritirachium oryzae, belonged to the Phylum Basidiomycota whereas the rest belonged to Ascomycota. Dothideomycetes was the dominant class with the highest isolation frequency of 49.2 %. The most frequent colonizers of the host were Alternaria spp., Pestalotiopsis spp., Preussia spp., and Sclerostagonospora spp. The diversity and species richness were higher in needle tissues than in the stems. Antimicrobial activities were displayed by extracts from a total number of 22 endophytes against one or more pathogens. Endophytes designated as P1N13 (Coniothyrium carteri), P2N8 (Thielavia subthermophila), P4S6b (Truncatella betulae), P7N10 (Cochliobolus australiensis), and P8S4 (Tritirachium oryzae) were highly active against Candida albicans. Broad spectrum antimicrobial activities were obtained with the extracts of P8-S4 (Tritirachium oryzae) and P5-N26 (Coniochaeta gigantospora) that were potentially active against the Gram-positive and Gram-negative bacteria as well as the fungal pathogen, Candida albicans. The most prominent antagonistic activity against fungal pathogens was shown by P8-S4 (Tritirachium oryzae), P5-N31a (Truncatella spadicea), and P5-N20 (Fusarium larvarum). Our findings indicate that Pinus wallichiana harbors a rich endophytic fungal community with potential antimicrobial activities. Further studies are needed to understand the ecology and evolutionary context of the associations between the Himalayan pine and its endophytes.     

Taxus associated fungal endophytes: anticancerous to other biological activities

Endophytes are the plant microorganisms that flourish inside plants (endosphere) and support the growth under normal and challenging environmental circumstances. Besides biological activities, microbial endophytes are important for their contribution in adaptation and survival of the host plants under stressed environments. While various species of Taxus have been globally recognized mainly due to their anticancer property, emphasis has also been on isolation of taxol producing endophytes in view of the taxonomic (endangered) status of the species. Furthermore, Taxus associated endophytes are also being recognized for the biological activities other than taxol production. The present study reviews the diversity of Taxus associated endophytes along with their biological activities. Available literature on Taxus associated endophytes revealed that T. chinensis has received maximum attention (19.5 %), followed by T. wallichiana (18.5 %), T. baccata (16.4 %), T. cuspidata (11.3 %), and T. mairei (10.3 %); with a minimum number of reports accounted for T. globose (1.0 %), and T. celebica (2.0 %). Most fungal endophytes have been identified as ascomycetes. Basidiomycetous endophytes have been reported in a limited number of studies. No endophytes have yet been identified from three species, namely T. controta (West Himalayan yew), T. floridana (Florida yew), and T. canadensis (Canadian yew). A total of 70 diverse endophytic species have been reported from different Taxus species. Fusarium sp. (25.2 %), Aspergillus sp. (17.6 %), Alternaria sp. (11.3 %), Penicillium sp. and Cladosporium sp. (10.0 %) are the five dominant genera. Furthermore, 59.6 % of studies from the reported literature are related to taxol production by fungal endophytes, 9.6 % related to antimicrobial activity, and a combined 15.3 % related to other biological activities, i.e., antifeeding, antimitogenic, antioxidant and cytotoxic activities. Additionally, 3.8 % of fungal endophytes were not studied for any of their biological activities. Only three bacterial endophytes namely Burkholderia sp., Enterobacter sp., and Pseudomonas sp., have been recorded from Taxus along with their contribution in plant growth, antagonistic, and antioxidant activities. Isolation and characterization of microbial endophytes from Taxus plant parts is important for the associated ecology and medicinally important biological activities. It will support the much-required conservation strategy of Taxus species. Further, isolation of plant growth promoting microorganisms from Taxus will help in propagation of the species.     

Endophytes from an Australian native plant are a promising source of industrially useful enzymes

Endophytes are microorganisms that live within plant tissues that are potential sources of novel bioactive compounds, including enzymes. We have identified endophytes of the Australian native plant Eremophilia longifolia which were screened for the production of industrially useful enzymes. Seventeen fungal endophytes were isolated from the leaves of E. longifolia and enzyme production was investigated within a range of pH (3.5, 5.5, 7 and 9) and temperatures (9, 25, 37 and 50 °C). Amylase was the most common enzyme encountered with numerous isolates showing production throughout the temperature and pH ranges. Protease production was also seen over the conditions tested but was more dominant at lower pH and temperature. Activity was not observed for other enzymes including ligninase, xylanase and cellobiohydrolase. Enzymes from isolates of Preussia minima, Alternaria sp. and an unclassified fungus, which showed highest activity in screening assays, were investigated further. Enzyme production was verified by zymography and the amylase activity of P. minima was found to be significantly greater than that of Aspergillus oryzae particularly in alkaline conditions and low temperature which are desirable properties for the detergent industry. This work shows that enzymes with potential use in industry can be readily identified in fungal endophytes.     

Fungal endophytes of invasive Phagramites australis populations vary in species composition and fungicide susceptibility

Phragmites australis subsp. australis (Poaceae) is an aggressively invasive reed that threatens both freshwater and saltwater ecosystems in North America. We sampled P.a. australis plants for fungal endophytes at seven sites across a short geographic range near a freshwater lake in Michigan. Compared to previous studies, our data reveal novel variation in the diversity and abundance of fungal endophytes within P.a. australis. Within each sampling site we observed 4–10 morphologically unique, culturable fungi. Since fungal endophytes can confer significant benefits to their plant host, we hypothesized that fungal endophytes are important for mediating plant invasions. To test this hypothesis we first had to establish a protocol to experimentally control fungal endophytes within P.a. australis, which does not easily grow from sterile seed. We therefore investigated the effect of fungicides as a potential method for eliminating fungi from living plant tissue such as rhizomes. We selected the ten most abundant fungi isolated from P.a. australis and tested their susceptibility to three commonly available fungicides. Response to the fungicides varied across fungal isolates, demonstrating physiological variation and fungicide-resistant phenotypes.     

Shifts in Symbiotic Endophyte Communities of a Foundational Salt Marsh Grass following Oil Exposure from the Deepwater Horizon Oil Spill

Symbiotic associations can be disrupted by disturbance or by changing environmental conditions. Endophytes are fungal and bacterial symbionts of plants that can affect performance. As in more widely known symbioses, acute or chronic stressor exposure might trigger disassociation of endophytes from host plants. We tested this hypothesis by examining the effects of oil exposure following the Deepwater Horizon (DWH) oil spill on endophyte diversity and abundance in Spartina alterniflora – the foundational plant in northern Gulf coast salt marshes affected by the spill. We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill. DNA sequence-based estimates showed that oil exposure shifted endophyte diversity and community structure. Plants from oiled areas exhibited near total loss of leaf fungal endophytes. Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites. These results show that plant-endophyte symbioses can be disrupted by stressor exposure, and indicate that symbiont community disassembly in marsh plants is an enduring outcome of the DWH spill.     

Diversity and ubiquity of xylariaceous endophytes in live and dead leaves of temperate forest trees

To test the hypothesis that xylariaceous endophytes were ubiquitous on live and dead leaves of various tree species in the field, xylariaceous fungi were isolated from live leaves and bleached and nonbleached portions of dead leaves of a total of 94 tree species in a cool temperate forest in Japan. The biodiversity of xylariaceous endophytes was evaluated as the richness of operational taxonomic units (OTUs) determined by phylogenetic analysis of the nucleotide sequence of the D1/D2 region of the LSU rDNA of fungal isolates. A total of 326 isolates of xylariaceous fungi were isolated from live and dead leaves and classified into 15 OTUs. The three major OTUs, Xylaria sp.1, Nemania sp., and Biscogniauxia sp., accounted for 94% (308 isolates) of the total number of isolates, and were isolated from various live and dead leaves. Xylaria sp.1 was frequently encountered on bleached portions (which were produced due to the selective decomposition of lignin) of dead leaves of broad-leaved deciduous tree species. The results suggest that xylariaceous endophytes did not show host specificity and had a saprobic phase on dead leaves in their life cycles and that Xylaria sp.1 was capable of decomposing lignin in the field conditions.     

The endophytic fungal communities associated with the leaves and roots of the common reed (Phragmites australis) in Lake Trasimeno (Perugia,Italy) in declining and healthy stands

We surveyed the fungal endophytes in the leaves and roots of Phragmites australis plants along a gradient of reed decline at Lake Trasimeno (central Italy) in Oct. 2010. An integrated approach consisting of cultivation and molecular identification was used. Endophytes were recovered from 61.59 % of the samples, with a total of 1 541 isolates. On the basis of a molecular analysis of the rDNA Internal Transcribed Spacer (ITS) region, 25 operational taxonomic units (OTUs) were identified. Fusarium sp. (OTU 21) and Gibberella moniliformis (OTU 1) were the most frequently isolated fungi. Comparisons of the leaf and root samples demonstrated spatial heterogeneity in the endophyte assemblages among the plant parts and sites. In this study, we have shown that reed plants in different states of decline harbour different endophytic communities. This finding may help to understand the very complex scenario of reed die-back.     

Geographic locality and host identity shape fungal endophyte communities in cupressaceous trees

Understanding how fungal endophyte communities differ in abundance, diversity, taxonomic composition, and host affinity over the geographic ranges of their hosts is key to understanding the ecology and evolutionary context of endophyte–plant associations. We examined endophytes associated with healthy photosynthetic tissues of three closely related tree species in the Cupressaceae (Coniferales): two native species within their natural ranges [Juniperus virginiana in a mesic semideciduous forest, North Carolina (NC); Cupressus arizonica, under xeric conditions, Arizona (AZ)], and a non-native species planted in each site (Platycladus orientalis). Endophytes were recovered from 229 of 960 tissue segments and represented at least 35 species of Ascomycota. Isolation frequency was more than threefold greater for plants in NC than in AZ, and was 2.5 (AZ) to four (NC) times greater for non-native Platycladus than for Cupressus or Juniperus. Analyses of ITS rDNA for 109 representative isolates showed that endophyte diversity was more than twofold greater in NC than in AZ, and that endophytes recovered in AZ were more likely to be host-generalists relative to those in NC. Different endophyte genera dominated the assemblages of each host species/locality combination, but in both localities, Platycladus harboured less diverse and more cosmopolitan endophytes than did either native host. Parsimony and Bayesian analyses for four classes of Ascomycota (Dothideomycetes, Sordariomycetes, Pezizomycetes, Eurotiomycetes) based on LSU rDNA data (ca 1.2 kb) showed that well-supported clades of endophytes frequently contained representatives of a single locality or host species, underscoring the importance of both geography and host identity in shaping a given plant's endophyte community. Together, our data show that not only do the abundance, diversity, and taxonomic composition of endophyte communities differ as a function of host identity and locality, but that host affinities of those communities are variable as well.     

Novel and highly diverse fungal endophytes in soybean revealed by the consortium of two different techniques

Fungal endophytes were isolated from the leaves of soybean cultivars in Brazil using two different isolation techniques — fragment plating and the innovative dilution-to-extinction culturing — to increase the species richness, frequency of isolates and diversity. A total of 241 morphospecies were obtained corresponding to 62 taxa that were identified by analysis of the internal transcribed spacer (ITS) of the ribosomal DNA (rDNA). The Phylum Ascomycota predominated, representing 99% and 95.2% of isolates in the Monsoy and Conquista cultivars, respectively, whereas the Phylum Basidiomycota represented 1% and 4.8% of isolates, respectively. The genera Ampelomyces, Annulohypoxylon, Guignardia, Leptospora, Magnaporthe, Ophiognomonia, Paraconiothyrium, Phaeosphaeriopsis, Rhodotorula, Sporobolomyces, and Xylaria for the first time were isolated from soybean; this suggests that soybean harbours novel and highly diverse fungi. The yeasts genera Rhodotorula and Sporobolomyces (subphylum Pucciniomycotina) represent the Phylum Basidiomycota. The species richness was greater when both isolation techniques were used. The diversity of fungal endophytes was similar in both cultivars when the same isolation technique was used except for Hill’s index, N₁. The use of ITS region sequences allowed the isolates to be grouped according to Order, Class and Phylum. Ampelomyces, Chaetomium, and Phoma glomerata are endophytic species that may play potential roles in the biological control of soybean pathogens. This study is one of the first to apply extinction-culturing to isolate fungal endophytes in plant leaves, thus contributing to the development and improvement of this technique for future studies.     

Spatial and temporal variation of fungal endophytic richness and diversity associated to the phyllosphere of olive cultivars

Fungal endophytes are micro-organisms that colonize healthy plant tissues without causing disease symptoms. They are described as plant growth and disease resistance promoters and have shown antimicrobial activity. The spatial-temporal distribution of endophytic communities in olive cultivars has been poorly explored. This study aims to investigate the richness and diversity of endophytic fungi in different seasons and sites, within the Alentejo region, Portugal. Additionally, and because the impact of some pathogenic fungi (e.g. Colletotrichum spp.) varies according to olive cultivars; three cultivars, Galega vulgar, Cobrançosa and Azeiteira, were sampled. 1868 fungal isolates were identified as belonging to 26 OTUs; 13 OTUs were identified to the genera level and 13 to species level. Cultivar Galega vulgar and season autumn showed significant higher values in terms of endophytic richness and diversity. At site level, Elvas showed the lowest fungal richness and diversity of fungal endophytes. This study reinforces the importance of exploring the combined spatio-temporal distribution of the endophytic biodiversity in different olive cultivars. Knowledge about endophytic communities may help to better understand their functions in plants hosts, such as their ecological dynamics with pathogenic fungi, which can be explored for their use as biocontrol agents.     

Fungal endophyte diversity and community patterns in healthy and yellowing leaves of Citrus limon

Fungal endophytes on citrus plants have been little studied, and the effects of citrus diseases on their incidence and diversity have not been addressed. In this study, we examined the foliar fungal endophytes of Citrus limon in the vicinity of Yaoundé, Cameroon, with emphasis on the differences between endophyte communities in healthy and yellowing leaves. From 82.3 % of the 480 leaf fragments, a total of 482 isolates were recovered and analysis of ITS sequences revealed 20 phylotypes. All fungal endophytes were ascomycetes and, except for one species, were common plant pathogens. Mycosphaerella and its anamorphs (34.2 % of all isolates), and Colletotrichum gloeosporioides (50.4 % of all isolates), were isolated most frequently. Mycosphaerellaceous species dominated in healthy leaves, and were absent from yellowing leaves. C. gloeosporioides was isolated significantly more frequently from yellowing than healthy leaves. Yellowing leaves had a significantly higher overall infection frequency but, in contrast, the least species diversity. Difference in the endophyte assemblages of healthy and yellowing leaves suggests that yellowing of leaves may facilitate the incidence of certain endophytes and impose growth inhibition on others.     

Impact of environmental variables on the isolation,diversity and antibacterial activity of endophytic fungal communities from Madhuca indica Gmel. at different locations in India

A total of 1,897 isolates of endophytic fungi from Madhuca indica Gmel., representing 40 morphologically distinct fungal taxa were obtained from 2,700 segments of stem, bark and leaf from three different locations (Loc 1, Loc 2 and Loc 3) in Uttar Pradesh, India. Out of 40 taxa, 28 were identified microscopically and the remaining 12 by molecular methods. Coelomycetes (62.41 %) were the most prevalent fungal group followed by hyphomycetes (28.89 %) and ascomycetes (8.70 %). Colonisation frequency (CF) was greater in stem (82.55 %) than in leaf (65.00 %) and bark (63.22 %). Due to the dominance of a few taxa, species richness and Shannon and Simpson diversity indices were lower in stem than in leaf and bark at each location. Interestingly, less rainfall and lower temperatures disfavoured the overall colonisation of fungal endophytes at Loc 2. The stem samples from all locations were very similar in their endophytic composition, whereas bark and leaf samples showed differences. The dominant endophytic fungi isolated were Phomopsis sp. 1 (9.185 %), and Colletotrichum gloeosporioides (7.00 %). Principal component analysis showed 55 % tissue specificity with 51.08 % maximum variance. Antibacterial activity revealed that 58.33 % endophytic fungi were active against at least one or more bacterial pathogens, whereas the crude extract of five endophytic fungi inhibited the growth of five or more than five (50 %) of the pathogens tested. This report illustrates the value of having an adequate sample size from different tissues and different locations for species and chemical diversity in search of novel natural products.     

Fungal palaeodiversity revealed using high‐throughput metabarcoding of ancient DNA from arctic permafrost

The taxonomic and ecological diversity of ancient fungal communities was assessed by combining next generation sequencing and metabarcoding of DNA preserved in permafrost. Twenty‐six sediment samples dated 16 000–32 000 radiocarbon years old from two localities in Siberia were analysed for fungal ITS. We detected 75 fungal OTUs from 21 orders representing three phyla, although rarefaction analyses suggested that the full diversity was not recovered despite generating an average of 6677 ± 3811 (mean ± SD) sequences per sample and that preservation bias likely has considerable effect on the recovered DNA. Most OTUs (75.4%) represented ascomycetes. Due to insufficient sequencing depth, DNA degradation and putative preservation biases in our samples, the recovered taxa probably do not represent the complete historic fungal community, and it is difficult to determine whether the fungal communities varied geographically or experienced a composition shift within the period of 16 000–32 000 bp . However, annotation of OTUs to functional ecological groups provided a wealth of information on the historic communities. About one‐third of the OTUs are presumed plant‐associates (pathogens, saprotrophs and endophytes) typical of graminoid‐ and forb‐rich habitats. We also detected putative insect pathogens, coprophiles and keratinophiles likely associated with ancient insect and herbivore faunas. The detection of putative insect pathogens, mycoparasites, aquatic fungi and endophytes broadens our previous knowledge of the diversity of fungi present in Beringian palaeoecosystems. A large group of putatively psychrophilic/psychrotolerant fungi was also detected, most likely representing a modern, metabolically active fungal community.     

Soil fungal community variation by large-scale reclamation in Sanjiang plain,China

Large-scale marshland reclamation can cause substantial changes to the soil fungal community by disturbances associated with the growth of crop plants and by the addition of fertilizers and pesticides. In this study, high-throughput sequencing of the fungal-specific internal transcribed spacer (ITS) gene region was used to identify fungal taxa. We analyzed the variation in soil fungi diversity and community composition in marshland, paddy, and farmland corn soils, and investigated the relationship between soil fungal community composition and soil physicochemical characteristics to quantify the effect of large-scale reclamation on marshland soil environment in the Sanjiang Plain, northeast China. Marshland soil contained most of the 1997 operational taxonomic units (OTUs) found across all sites (1241), while paddy soil had only 614 OTUs and farmland corn soil 817 OTUs. All reclaimed lands presented a decline in richness and diversity of soil fungi at the OTU level, and soil fungal richness was significantly different between marshland and reclaimed sites (P < 0.05), although it did not differ significantly between marshland and farmland corn sites. Additionally, soil fungal community composition showed different trends and structure after the reclamation. One-way analysis of variance showed Basidiomycota, Zygomycota, Glomeromycota, and Chytridiomycota composition differed significantly between marshland and reclaimed sites (P < 0.05). Nine dominant genera (relative abundance >1.5% in at least one site) and many unclassified genera showed significant variation between marshland and reclaimed sites, including Blumeria, Tomentella, Peziza, Hypholoma, Zopfiella, Mrakia, and Fusarium. Soil fungal community composition and diversity were affected by soil moisture, pH, total carbon (C), available nitrogen (N), soil organic carbon, soil dissolved organic carbon, and C/N (the ratio of total carbon to total nitrogen). The present results contribute to understanding the fungal community in marshland ecosystems, and the role of environmental variability as a predictor of fungal community composition.