Soil fungal community structure and function response to rhizoma perennial peanut cultivars.

BACKGROUND: Crop-associated microorganisms play a crucial role in soil nutrient cycling, and crop growth, and health. Fine-scale patterns in soil microbial community diversity and composition are commonly regulated by plant species or genotype. Despite extensive reports in different crop or its cultivar effects on the microbial community, it is uncertain how rhizoma peanut (RP, Arachis glabrata Benth.), a perennial warm-season legume forage that is well-adapted in the southern USA, affects soil microbial community across different cultivars. RESULTS: This study explored the influence of seven different RP cultivars on the taxonomic composition, diversity, and functional groups of soil fungal communities through a field trial in Marianna, Florida, Southern USA, using next-generation sequencing technique. Our results showed that the taxonomic diversity and composition of the fungal community differed significantly across RP cultivars. Alpha diversity (Shannon, Simpson, and Pielou's evenness) was significantly higher in Ecoturf but lower in UF_Peace and Florigraze compared to other cultivars (p < 0.001). Phylogenetic diversity (Faith's PD) was lowest in Latitude compared to other cultivars (p < 0.0001). The dominant phyla were Ascomycota (13.34%), Mortierellomycota (3.82%), and Basidiomycota (2.99%), which were significantly greater in Florigraze, UF_Peace, and Ecoturf, respectively. The relative abundance of Neocosmospora was markedly high (21.45%) in UF_Tito and showed large variations across cultivars. The relative abundance of the dominant genera was significantly greater in Arbrook than in other cultivars. There were also significant differences in the co-occurrence network, showing different keystone taxa and more positive correlations than the negative correlations across cultivars. FUNGuild analysis showed that the relative abundance of functional guilds including pathogenic, saprotrophic, endophytic, mycorrhizal and parasitic fungi significantly differed among cultivars. Ecoturf had the greatest relative abundance of mycorrhizal fungal group (5.10 ± 0.44), whereas UF_Peace had the greatest relative abundance of endophytic (4.52 ± 0.56) and parasitic fungi (1.67 ± 0.30) compared to other cultivars. CONCLUSIONS: Our findings provide evidence of crop cultivar's effect in shaping fine-scale fungal community patterns in legume-based forage systems.

Metabolic profiling, antimicrobial, anticancer, and in vitro and in silico immunomodulatory investigation of Aspergillus niger OR730979 isolated from the Western Desert, Egypt.

Ten fungal species were isolated from soil in the Western Desert and Wadi El-Natron in Egypt. All fungal isolates were morphologically recognized down to the species level. Methanol extracts of fungal mycelia and ethyl acetate extracts of culture filtrate from the isolated fungi were evaluated for antimicrobial activity against six pathogenic bacteria and one pathogenic yeast (Candida albicans ATCC20231). Only ethyl acetate extracts of Fusarium circinatum, Aspergillus niger, and Aspergillus terreus culture filtrates showed significant antimicrobial activity against the majority of the investigated pathogens. The culture filtrate extract of Aspergillus niger exhibited notable cytotoxicity towards the breast cancer (MCF-7) cell line, with the lowest detected IC50 recorded at 8 µg/µl. Whereas Fusarium circinatum and Aspergillus terreus had IC50s of 15.91 µg/µl and 18 µg/µl, respectively. A gas chromatography-mass spectroscopy (GC-MS) investigation of A. niger's potent extract revealed 23 compounds with different biological activities. Glycidyleoleate was found to be the main extract component. Aspergillus niger extract was chosen to study its possible cytotoxic mechanism. The extract was found to induce apoptosis and cell cycle arrest at the < 2n stage. Despite a significant increase in caspases 8 and 9, the production levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) have shown a significant decrease. The high interaction of glycidyleoleate against the studied cytokines' binding receptors was demonstrated via docking studies. In conclusion, the available data revealed that the culture filtrate extract of A. niger possesses promising antimicrobial, cytotoxic, and immunomodulatory properties.

Plant Community Associates with Rare Rather than Abundant Fungal Taxa in Alpine Grassland Soils.

The importance of the rare microbial biosphere in maintaining biodiversity and ecological functions has been highlighted recently. However, the current understanding of the spatial distribution of rare microbial taxa is still limited, with only a few investigations for rare prokaryotes and virtually none for rare fungi. Here, we investigated the spatial patterns of rare and abundant fungal taxa in alpine grassland soils across 2,000 km of the Qinghai-Tibetan plateau. We found that most locally rare fungal taxa remained rare (13.07%) or were absent (82.85%) in other sites, whereas only a small proportion (4.06%) shifted between rare and abundant among sites. Although they differed in terms of diversity levels and compositions, the distance decay relationships of both the rare and the abundant fungal taxa were valid and displayed similar turnover rates. Moreover, the community assemblies of both rare and abundant fungal taxa were predominantly controlled by deterministic rather than stochastic processes. Notably, the community composition of rare rather than abundant fungal taxa associated with the plant community composition. In summary, this study advances our understanding of the biogeographic features of rare fungal taxa in alpine grasslands and highlights the concordance between plant communities and rare fungal subcommunities in soil. IMPORTANCE Our current understanding of the ecology and functions of rare microbial taxa largely relies on research conducted on prokaryotes. Despite the key ecological roles of soil fungi, little is known about the biogeographic patterns and drivers of rare and abundant fungi in soils. In this study, we investigated the spatial patterns of rare and abundant fungal taxa in Qinghai-Tibetan plateau (QTP) alpine grassland soils across 2,000 km, with a special concentration on the importance of the plant communities in shaping rare fungal taxa. We showed that rare fungal taxa generally had a biogeographic pattern that was similar to that of abundant fungal taxa in alpine grassland soils on the QTP. Furthermore, the plant community composition was strongly related to the community composition of rare taxa but not abundant taxa. In summary, this study significantly increases our biogeographic and ecological knowledge of rare fungal taxa in alpine grassland soils.

Abiotic and Biotic Drivers of Soil Fungal Communities in Response to Dairy Manure Amendment.

Modern agriculture often relies on large inputs of synthetic fertilizers to maximize crop yield potential, yet their intensive use has led to nutrient losses and impaired soil health. Alternatively, manure amendments provide plant available nutrients, build organic carbon, and enhance soil health. However, we lack a clear understanding of how consistently manure impacts fungal communities, the mechanisms via which manure impacts soil fungi, and the fate of manure-borne fungi in soils. We assembled soil microcosms using five soils to investigate how manure amendments impact fungal communities over a 60-day incubation. Further, we used autoclaving treatments of soils and manure to determine if observed changes in soil fungal communities were due to abiotic or biotic properties, and if indigenous soil communities constrained colonization of manure-borne fungi. We found that manure amended soil fungal communities diverged from nonamended communities over time, often in concert with a reduction in diversity. Fungal communities responded to live and autoclaved manure in a similar manner, suggesting that abiotic forces are primarily responsible for the observed dynamics. Finally, manure-borne fungi declined quickly in both live and autoclaved soil, indicating that the soil environment is unsuitable for their survival. IMPORTANCE Manure amendments in agricultural systems can impact soil microbial communities via supplying growth substrates for indigenous microbes or by introducing manure-borne taxa. This study explores the consistency of these impacts on soil fungal communities and the relative importance of abiotic and biotic drivers across distinct soils. Different fungal taxa responded to manure among distinct soils, and shifts in soil fungal communities were driven largely by abiotic factors, rather than introduced microbes. This work demonstrates that manure may have inconsistent impacts on indigenous soil fungi, and that abiotic properties of soils render them largely resistant to invasion by manure-borne fungi.

Do ectomycorrhizal exploration types reflect mycelial foraging strategies?

Ectomycorrhizal exploration types are commonly assumed to denote spatial foraging patterns and resource-related niches of extraradical mycelia. However, empirical evidence of the consistency of foraging strategies within exploration types is lacking. Here, we analysed ectomycorrhizal foraging patterns by incubating root-excluding ingrowth mesh bags filled with six different substrates in mature Picea abies forests. High-throughput sequencing was used to characterise ectomycorrhizal fungal communities in the mesh bags and on adjacent fine roots after one growing season. Contrary to expectations, many ectomycorrhizal genera of exploration types that are thought to produce little extraradical mycelium colonised ingrowth bags extensively, whereas genera commonly associated with ample mycelial production occurred sparsely in ingrowth bags relative to their abundance on roots. Previous assumptions about soil foraging patterns of exploration types do not seem to hold. Instead, we propose that variation in the proliferation of extraradical mycelium is related to intergeneric differences in mycelial longevity and the mobility of targeted resources.

The high diversity of Scedosporium and Lomentospora species and their prevalence in human-disturbed areas in Taiwan.

Scedosporium and Lomentospora are important opportunistic pathogens causing localized or disseminated infection in humans. Understanding their environmental distribution is critical for public hygiene and clinical management. We carried out the first environmental survey in urbanized and natural regions in Taiwan. Overall, Scedosporium and Lomentospora species were recovered in 132 out of 273 soil samples (48.4%) across Taiwan. We morphologically and molecularly identified six Scedosporium and one Lomentospora species. All four major clinical relevant species were isolated with high frequency, i.e., Scedosporium apiospermum (42.4%), S. boydii (21.8%), Lomentosporaprolificans (14.5%), S. aurantiacum (8.5%); two clinically minor species, Pseudallescheria angusta (6.7%) and S. dehoogii (5.6%), and a saprobic species, S. haikouense (0.6%), had moderate to rare incidence. These fungal species had high incidence in urban (48.6%) and hospital (67.4%) soil samples, and had limited distribution in samples from natural regions (5%). Multivariate analysis of the fungal composition revealed strong evidence of the preferential distribution of these fungi in urban and hospital regions compared with natural sites. In addition, strong evidence suggested that the distribution and abundance of these fungal species were highly heterogeneous in the environment; samples in vicinity often yielded varied fungal communities. We concluded that these fungal species were prevalent in soil in Taiwan and their occurrences were associated with human activities. Although, hygiene sensitive sites such as hospitals were not harboring heavier fungal burdens than other urban facilities in our survey, still, aware should be taken for the high frequency of these clinical relevant species around hospital regions.

Scedosporium and Lomentospora are two fungal genera that can cause infections to wildlife and humans. Our experiment demonstrated that these fungi are ubiquitous in the soil in Taiwan. Their proximity to human-dwelling regions raises our awareness of their exposure to those who are susceptible.

Long-Read Sequencing Analysis Revealed the Impact of Forest Conversion on Soil Fungal Diversity in Limu Mountain, Hainan.

Soil fungi are essential to soil microorganisms that play an important role in the ecosystem's soil carbon cycle and mineral nutrient transformation. Understanding the structural characteristics and diversity of soil fungal communities helps understand the health of forest ecosystems. The transition from tropical rainforest to artificial forest greatly impacts the composition and diversity of fungal communities. Hainan Limushan tropical rainforest National Park has a large area of artificial forests. Ecologists have conducted in-depth studies on the succession of animals and plants to regenerate tropical rainforests. There are few reports on the diversity of soil fungi and its influencing factors in the succession of tropical rainforests in Limu Mountain. In this study, 44 soil samples from five different stands were collected in the tropical rainforest of Limushan, Hainan. High-throughput sequencing of rDNA in its region was used to analyze fungal communities and study their α and ß diversity. Analysis of variance and multiple regression models was used to analyze soil variables and fungal functional groups to determine the effects of interaction between fungi and environmental factors. A total of 273,996 reads and 1290 operational taxonomic units (OTUs) were obtained, belonging to 418 species, 325 genera, 159 families, eight phyla, 30 classes, and 73 orders. The results showed that the composition of soil fungal communities in the five stands was similar, with ascomycetes accounting for 70.5% and basidiomycetes accounting for 14.7%. α and ß diversity analysis showed that soil fungi in Limushan tropical rainforest had high abundance and diversity. Multiple regression analysis between soil variables and functional groups showed that organic matter, TN, TP, TK, and AK were excellent predictors for soil fungi. TP was the strongest predictor in all functional groups except soil saprotroph. Organic matter and total nitrogen were the strongest predictors of soil rot. The transformation from tropical rainforest to artificial forest in Limushan did not change the soil fungal community structure, but the richness and diversity of soil fungi changed. The forest transformation did not lead to decreased soil fungal abundance and diversity. Different vegetation types and soil properties affect the diversity of soil fungal communities. We found that Caribbean pine plantations can improve soil fungal diversity, while long-term Eucalyptus spp. plantations may reduce soil fungal diversity.

Two New Species of Talaromyces Sect. Trachyspermi Discovered in China.

Two new species of sect. Trachyspermi isolated from soil are proposed, namely, T. albidus (ex-type AS3.26143T) and T. rubidus (ex-type AS3.26142T), based on the integrated taxonomic methods. Morphologically, T. albidus is characterized by slow growth, white gymnothecia, singly-borne asci and ellipsoidal echinulate ascospores. Talaromyces rubidus is distinguished by restricted growth, moderate to abundant red soluble pigment on CYA and YES, biverticillate penicilli, and  commonly ovoid to globose echinulate conidia. The two proposed novelties are further confirmed by the phylogenetic analyses of the concatenated BenA-CaM-Rpb2-ITS sequence matrix and the individual BenA, CaM, Rpb2 and ITS sequence matrices. Talaromyces albidus is closely related to T. assiutensis and T. trachyspermus, while T. rubidus is in the clade containing T. albobiverticillius, T. rubrifaciens, T. catalonicus, T. heiheensis, T. erythromellis, T. halophytorum, T. pernambucoensis, T. solicola and T. aerius.

Spatiotemporal dynamics and functional characteristics of the composition of the main fungal taxa in the root microhabitat of Calanthe sieboldii (Orchidaceae).

BACKGROUND: Endophytic fungi play a critical ecological role in the growth and development of orchids, but little is known about the spatial and temporal dynamics of fungal diversity or the ecological functions of fungi during orchid growth and reproduction. Calanthe sieboldii Decne. is listed in the Chinese National Key Protected Wild Plants as a class I protected wild plant. To understand the community characteristics of root and soil fungi of the orchid during its reproductive seasons, we investigated the community composition, spatial and temporal dynamics, and functional characteristics of the orchid microhabitat fungi by using diversity and ecological functional analyses. RESULTS: We discovered that there were three, seven, and four dominant fungal families in the orchid's roots, rhizoplane soil, and rhizosphere soil, respectively. Tulasnellaceae, Aspergillaceae, and Tricholomataceae were the dominant fungi in this endangered orchid's microhabitats. The closer the fungal community was to the orchid, the more stable and the less likely the community composition to change significantly over time. The fungal communities of this orchid's roots and rhizoplane soil varied seasonally, while those of the rhizosphere soil varied interannually. Saprophytic fungi were the most abundant in the orchid's fungal community, and the closer the distance to the orchid, the more symbiotic fungi were present. CONCLUSIONS: The fungi in different parts of the root microhabitat of C. sieboldii showed different spatiotemporal dynamic patterns. The fungal community near the orchid roots was relatively stable and displayed seasonal variation, while the community further away from the roots showed greater variation. In addition, compared with the soil fungi, the dominant endophytic fungi were more stable, and these may be key fungi influencing orchid growth and development. Our study on the spatiotemporal dynamics and functions of fungi provides a basis for the comprehensive understanding and utilization of orchid endophytic fungi.

Keratinophyton chongqingense sp. nov. and Keratinophyton sichuanense sp. nov., from soil in China.

Keratinophyton is a genus of well-known keratinophilic fungi found in various terrestrial habitats. During a survey of keratinolytic fungi in China, a total of 12 isolates of Keratinophyton species, representing eight taxa, were obtained from the soil. Two of these isolates were described as new species based on their morphological characteristics and molecular analyses of the internal transcribed spacer region and the rRNA gene of the nuclear large subunit. Descriptions and illustrations of these two novel species, which are named Keratinophyton chongqingense sp. nov. and Keratinophyton sichuanense sp. nov., are provided herein.

Plant effects on and response to soil microbes in native and non-native Phragmites australis.

Plant-soil feedbacks (PSFs) mediate plant community dynamics and may plausibly facilitate plant invasions. Microbially mediated PSFs are defined by plant effects on soil microbes and subsequent changes in plant performance (responses), both positive and negative. For microbial interactions to benefit invasive plants disproportionately, native and invasive plants must either (1) have different effects on and responses to soil microbial communities or (2) only respond differently to similar microbial communities. In other words, invasive plants do not need to cultivate different microbial communities than natives if they respond differently to them. However, effects and responses are not often explored separately, making it difficult to determine the underlying causes of performance differences. We performed a reciprocal-transplant PSF experiment with multiple microbial inhibition treatments to determine how native and non-native lineages of Phragmites australis affect and respond to soil bacteria, fungi, and oomycetes. Non-native Phragmites is a large, fast-growing, cosmopolitan invasive plant, whereas the North American native variety is comparatively smaller, slower growing, and typically considered a desirable wetland plant. We identified the effects of each plant lineage on soil microbes using DNA meta-barcoding and linked plant responses to microbial communities. Both Phragmites lineages displayed equally weak, insignificant PSFs. We found evidence of slight differential effects on microbial community composition, but no significant differential plant responses. Soils conditioned by each lineage differed only slightly in bacterial community composition, but not in fungal composition. Additionally, native and non-native Phragmites lineages did not significantly differ in their response to similar soil microbial communities. Neither lineage appreciably differed when plant biomass was compared between those grown in sterile and live soils. Targeted microbial inhibitor treatments revealed both lineages were negatively impacted by soil bacteria, but the negative response was stronger in non-native Phragmites. These observations were opposite of expectations from invasion theory and imply that the success of non-native Phragmites, relative to the native lineage, does not result from its interaction with soil microorganisms. More broadly, quantifying plant effects on, and responses to soil microbes separately provides detailed and nuanced insight into plant-microbial interactions and their role in invasions, which could inform management outcomes for invasive plants.

Diversity of soil fungi in the vineyards of Changli region in China.

This study aimed to elucidate the fungal diversity of Changli vineyard soil in China. High-throughput sequencing technology was used to investigate the diversity and composition of soil fungi in five vineyards from different geographical locations in Changli. Although the five vineyards had similar fungal communities, the diversity, composition, and distribution of the high-abundance species differed. Ascomycota, Basidiomycota, and Mortierellomycota were dominant phyla. Among the 14 high-abundance genera of fungi, Odiodendron, Pleotrichocladium, and Plectosephalella have rarely been reported in other vineyards and are unique to the Changli region. In addition, Solicoccozyma aeria and Solicoccozyma terrea were the dominant species in the five vineyards and have rarely been reported in domestic vineyards. Additionally, Rhizophagus, Wardomyces, Mortierella, Volutella, and Cryptococcus were significantly different among the five vineyard soils. Among these species, Mortierella was highly abundant in each vineyard, but its contents were significantly different across vineyards. These findings enrich the information on the composition and diversity of soil fungi in the vineyard of the Changli region, which helps to explore the regional or distinctive sensorial attributes of wine from the perspective of microbial biogeography.

Consolidation of Chloridium: new classification into eight sections with 37 species and reinstatement of the genera Gongromeriza and Psilobotrys.

Chloridium is a little-studied group of soil- and wood-inhabiting dematiaceous hyphomycetes that share a rare mode of phialidic conidiogenesis on multiple loci. The genus has historically been divided into three morphological sections, i.e. Chloridium, Gongromeriza, and Psilobotrys. Sexual morphs have been placed in the widely perceived genus Chaetosphaeria, but unlike their asexual counterparts, they show little or no morphological variation. Recent molecular studies have expanded the generic concept to include species defined by a new set of morphological characters, such as the collar-like hyphae, setae, discrete phialides, and penicillately branched conidiophores. The study is based on the consilience of molecular species delimitation methods, phylogenetic analyses, ancestral state reconstruction, morphological hypotheses, and global biogeographic analyses. The multilocus phylogeny demonstrated that the classic concept of Chloridium is polyphyletic, and the original sections are not congeneric. Therefore, we abolish the existing classification and propose to restore the generic status of Gongromeriza and Psilobotrys. We present a new generic concept and define Chloridium as a monophyletic, polythetic genus comprising 37 species distributed in eight sections. In addition, of the taxa earlier referred to Gongromeriza, two have been redisposed to the new genus Gongromerizella. Analysis of published metabarcoding data showed that Chloridium is a common soil fungus representing a significant (0.3 %) proportion of sequence reads in environmental samples deposited in the GlobalFungi database. The analysis also showed that they are typically associated with forest habitats, and their distribution is strongly influenced by climate, which is confirmed by our data on their ability to grow at different temperatures. We demonstrated that Chloridium forms species-specific ranges of distribution, which is rarely documented for microscopic soil fungi. Our study shows the feasibility of using the GlobalFungi database to study the biogeography and ecology of fungi. Taxonomic novelties: New genus: Gongromerizella Réblová; New sections: Chloridium section Cryptogonytrichum Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium section Gonytrichopsis Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium section Metachloridium Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium section Volubilia Réblová, Hern.-Restr., M. Kolarík & F. Sklenar; New species: Chloridium bellum Réblová & Hern.-Restr., Chloridium biforme Réblová & Hern.-Restr., Chloridium detriticola Réblová & Hern.-Restr., Chloridium gamsii Réblová & Hern.-Restr., Chloridium guttiferum Réblová & Hern.-Restr., Chloridium moratum Réblová & Hern.-Restr., Chloridium peruense Réblová & Hern.-Restr., Chloridium novae-zelandiae Réblová & Hern.-Restr., Chloridium elongatum Réblová & Hern.-Restr., Chloridium volubile Réblová & Hern.-Restr.; New varieties: Chloridium bellum var. luteum Réblová & Hern.-Restr., Chloridium detriticola var. effusum Réblová & Hern.-Restr., Chloridium chloridioides var. convolutum Réblová & Hern.-Restr.; New combinations: Chloridium section Gonytrichum (Nees & T. Nees) Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium section Mesobotrys (Sacc.) Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium section Pseudophialocephala (M.S. Calabon et al.) Réblová, Hern.-Restr., M. Kolarík & F. Sklenar, Chloridium simile (W. Gams & Hol.-Jech.) Réblová & Hern.-Restr., Chloridium chloridioides (W. Gams & Hol.-Jech.) Réblová & Hern.-Restr., Chloridium subglobosum (W. Gams & Hol.-Jech.) Réblová & Hern.-Restr., Chloridium fuscum (Corda) Réblová & Hern.-Restr., Chloridium ypsilosporum (Hol.-Jech.) Réblová & Hern.-Restr., Chloridium costaricense (G. Weber et al.) Réblová & Hern.-Restr., Chloridium cuneatum (N.G. Liu et al.) Réblová & Hern.-Restr., Fusichloridium cylindrosporum (W. Gams & Hol.-Jech.) Réblová, Gongromeriza myriocarpa (Fr.) Réblová, Gongromeriza pygmaea (P. Karst.) Réblová, Gongromerizella lignicola (F. Mangenot) Réblová, Gongromerizella pachytrachela (W. Gams & Hol.-Jech) Réblová, Gongromerizella pini (Crous & Akulov) Réblová; New name: Chloridium pellucidum Réblová & Hern.-Restr.; Epitypifications (basionyms): Chaetopsis fusca Corda, Gonytrichum caesium var. subglobosum W. Gams & Hol.-Jech.; Lectotypification (basionym): Gonytrichum caesium Nees & T. Nees. Citation: Réblová M, Hernández-Restrepo M, Sklenár F, Nekvindová J, Réblová K, Kolarík M (2022). Consolidation of Chloridium: new classification into eight sections with 37 species and reinstatement of the genera Gongromeriza and Psilobotrys. Studies in Mycology 103: 87-212. doi: 10.3114/sim.2022.103.04.

Shift of soil fungal communities under afforestation in Nanliu River Basin, southwest China.

Although soil fungi play a pivotal role in determining soil ecosystematic feedbacks to afforestation, there remains a big knowledge gap in the effects of afforestation on soil fungal communities, especially at a watershed scale. In this study, the variations of soil fungal diversity and community structures under afforestation were investigated in Nanliu River Basin, where paddy field and dry farmland were converted to eucalyptus plantation at an unprecedented speed. Spatial distance along the upper, middle and lower reaches of the Basin were also considered to analyze the dominant sources of the variations. The results demonstrated that eucalyptus afforestation had little effect on soil fungal diversity but could significantly influence fungal community structures. As paddy field and dry farmland converted to eucalyptus plantation, dominant fungal phylum shifted from Ascomycota to Ascomycota and Basidiomycota. Compared with afforestation from dry farmland, much bigger variation of fungal community structures was found in afforestation from paddy field. In addition, the significant change of fungal community structures exhibited in the upper reaches was from dry farmland, while presented in the middle reaches was from paddy field. However, afforestation comprised a larger source of variation than spatial distance within the soil fungal community structures, and Fusarium, Westerdykella,Zopfiella and Scleroderma were the most sensitive genera affected by afforestation. These results showed that afforestation did not always cause soil fungal diversity change and the heterogeneity of fungal community structures under afforestation was mainly controlled by original land use practices, while spatial distance partly decided the results.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study.

Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Invasion-induced root-fungal disruptions alter plant water and nitrogen economies.

Despite widespread evidence that biological invasion influences both the biotic and abiotic soil environments, the extent to which these two pathways underpin the effects of invasion on plant traits and performance remains unknown. Leveraging a long-term (14-year) field experiment, we show that an allelochemical-producing invader affects plants through biotic mechanisms, altering the soil fungal community composition, with no apparent shifts in soil nutrient availability. Changes in belowground fungal communities resulted in high costs of nutrient uptake for native perennials and a shift in plant traits linked to their water and nutrient use efficiencies. Some plants in the invaded community compensate for the disruption of nutritional symbionts and reduced nutrient provisioning by sanctioning more nitrogen to photosynthesis and expending more water, which demonstrates a trade-off in trait investment. For the first time, we show that the disruption of belowground nutritional symbionts can drive plants towards alternative regions of their trait space in order to maintain water and nutrient economics.

Drought induces shifts in soil fungal communities that can be linked to root traits across 24 plant species.

Root traits respond to drought in a species-specific manner, but little is known about how soil fungal communities and root traits respond to drought in concert. In a glasshouse experiment, we determined the response of soil pathogens, saprotrophs, and mutualistic and all fungi associated with the roots of 24 plant species subjected to drought. At harvest, soil fungal communities were characterized by sequencing. Data on root traits were extracted from a previously published work. Differences in fungal beta diversity between drought and control were plant species specific. For some species, saprotrophic fungi increased in relative abundance and richness with drought, whereas mutualistic fungi showed the opposite pattern. Community structure of pathogenic fungi was plant species specific but was slightly affected by drought. Pathogen composition was correlated with specific root surface area and root : shoot, saprotroph abundance with root tissue density, whereas mutualist composition was correlated with root : shoot. All these were the fungal attributes that best predicted shoot mass. Fungal response to drought depended highly on the fungal group and was related to root trait adjustments to water scarcity. This provides new insights into the role that root trait adjustments to drought may have in modulating plant-fungus interactions in grasslands ecosystems.

Root traits explain rhizosphere fungal community composition among temperate grassland plant species.

While it is known that interactions between plants and soil fungi drive many essential ecosystem functions, considerable uncertainty exists over the drivers of fungal community composition in the rhizosphere. Here, we examined the roles of plant species identity, phylogeny and functional traits in shaping rhizosphere fungal communities and tested the robustness of these relationships to environmental change. We conducted a glasshouse experiment consisting of 21 temperate grassland species grown under three different environmental treatments and characterised the fungal communities within the rhizosphere of these plants. We found that plant species identity, plant phylogenetic relatedness and plant traits all affected rhizosphere fungal community composition. Trait relationships with fungal communities were primarily driven by interactions with arbuscular mycorrhizal fungi, and root traits were stronger predictors of fungal communities than leaf traits. These patterns were independent of the environmental treatments the plants were grown under. Our results showcase the key role of plant root traits, especially root diameter, root nitrogen and specific root length, in driving rhizosphere fungal community composition, demonstrating the potential for root traits to be used within predictive frameworks of plant-fungal relationships. Furthermore, we highlight how key limitations in our understanding of fungal function may obscure previously unmeasured plant-fungal interactions.

Fungal community dynamics across a forest-alpine ecotone.

Climate change is causing upward shift of forest lines worldwide, with consequences for soil biota and carbon (C) sequestration. We here analyse compositional changes in the soil biota across the forest line ecotone, an important transition zone between different ecosystems. We collected soil samples along transects stretching from subalpine mountain birch forests to alpine heath. Soil fungi and micro-eukaryotes were surveyed using DNA metabarcoding of the ITS2 and 18S markers, while ergosterol was used to quantify fungal biomass. We observed a strong shift in the soil biota across the forest line ecotone: Below the forest line, there were higher proportions of basidiomycetes and mucoromycetes, including ectomycorrhizal and saprotrophic fungi. Above it, we observed relatively more root-associated ascomycetes, including Archaeorhizomycetes, ericoid mycorrhizal fungi and dark septate endophytes. Ergosterol and percentage C content in soil correlated strongly and positively with the abundance of root-associated ascomycetes. The predominance of ectomycorrhizal and saprotrophic fungi below the forest line probably promote high C turnover, while root-associated ascomycetes above the forest line may enhance C sequestration. With further rise in forest lines, there will be a corresponding shift in the below-ground biota, probably leading to enhanced release of soil C.

Stochastic community assembly decreases soil fungal richness in arid ecosystems.

Uncovering the linkages between community assembly and species diversity is a fundamental issue in microbial ecology. In this study, a large-scale (transect intervals of 1257.6 km) cross-biome soil survey was conducted, which ranged over agricultural fields, forests, wetlands, grasslands and desert, in the arid regions of northwest China. The aim was to investigate the biogeographic distribution, community assembly and species co-occurrence of soil fungi. The fungal communities in agricultural soils exhibited a steeper distance-decay slope and wider niche breadths, and were more strongly affected by stochastic assembly processes, than fungi in other natural habitats. A strong relationship was revealed between soil fungal richness and community assembly in arid ecosystems, with the influence of stochastic assembly processes decreasing with increasing fungal richness. Moreover, aridity was the most important environmental factor influencing fungal richness, ß-diversity and species co-occurrence patterns. Specifically, the predicted increase in arid conditions will probably reduce fungal richness and network complexity. These findings represent a considerable advance in linking fungal richness to mechanisms underlying the biogeographic patterns and assembly processes of fungal communities in arid ecosystems. These results can thus be used to forecast species co-occurrence and diversities pattern of soil fungi under climate aridity and land-use change scenarios.