Distribution Of Fungal Communities Research Articles

The presence of a significant endophytic fungus in mycobiome of rice seed compartments

Seed microbial communities have been known to have a crucial role in the life cycle of a plant. In this study, we examined the distribution of the fungal communities in three compartments (husk, brown rice, and milled rice) of the fourteen rice seed samples. Ten fungal genera distributed throughout the three compartments of the rice seeds were identified as the core mycobiome of the rice seeds, regardless of collecting regions or cultivars. Based on the diversity analysis, the distribution of the fungal community in milled rice was found to be more diversified, evenly distributed, and differently clustered from the other two compartments. Among the core mycobiome, Moesziomyces dominated almost 80% of the fungal communities in the outer compartments of rice seeds, whereas the abundances of other endophytic pathogenic fungi declined. Our results provide that antagonistic yeast Moesziomyces may be able to control the endogenous pathogenic fungal communities in rice seeds, hence maintaining the quality of rice seeds. In addition, the distribution of fungal communities differs depending on the rice seed’s compartment, indicating that the compartment can affect the distribution of the seed microbial community.

Fungal community composition varies spatially in a commercial potato field in response to soil properties and topographic features

The factors influencing the spatial distribution of fungal communities are commonly examined over large spatial scales but not at smaller scales. Given this, the extent to which soil properties and topographic features contribute to the diversity and distribution of fungal communities in an agricultural field needs to be further explored. We investigated the spatial distribution of soil fungal community composition from a ~1100 m long transect with 83 sampling points in a commercial potato field with a rolling landform. The relative abundance of Ascomycota, Basidiomycota and Mortierellomycota showed medium to strong spatial dependence with an autocorrelation range varying from ~43 to 92 m, similar to the autocorrelation range of soil properties and topographic features. Most of the variability in fungal and saprotrophic community composition was explained by soil properties (15% and 11%, respectively) and spatial distance (16% and 15% respectively). While topographic features contributed 8% and 5% of variability to total fungi and saprotrophic community composition, respectively. The fungal and saprotrophic community compositions were correlated with SOC, pH and slope curvature, however, richness and Pielou’s evenness of the fungal communities and fungal biomass were not correlated with soil properties or topographic features. The results suggest that the spatial variation in fungal and saprotrophic community composition in response to soil properties and topographic features in this agricultural landscape was due to differences in assemblages of fungal Amplicon Sequence Variants (ASVs) but not in differences in the number of fungal ASVs or fungal biomass measured using phospholipids fatty acids.

Unveiling the mycobiome of ecological importance from termitarium soils

BackgroundTermitarium is an intricate biological home with exceptional physicochemical soil properties and numerous beneficial microbiomes. The termitarium microbiome plays a role in several bionetwork processes. It contributes significantly to sustainable agriculture, forestry, and horticulture. In contrast to the immense number of research works focusing on termitarium bacteria and archaea, the amount of study about termitarium fungal communities is limited. This is despite the fact that fungi significantly contribute to the cycling of energy and matter on Earth. Thus, this study investigates the metagenomic datasets from termitarium soil collected from agricultural soils, to obtain a depiction of their mycobiome of ecological importance.ResultsOur dataset showed that Ascomycota was the most rank phylum, while Basidiomycota was the next in rank. Specifically, we identified numerous fungi of commercially importance, for example, producers of cellulases and cellulosomes. This was strengthened with the presence of functional genes/enzymes capable of promoting plant growth traits and defence system. Analysis further shown that soil properties influenced the distribution of fungal communities. Magnesium, nitrogen, and potassium, for example, were observed to be among the best predictor of fungal distribution and explained 87.40% of the total variation.ConclusionThis study epitomize further insights into the mycobiome of termitarium soils that are of ecological interest. Again, with some of our sequences assembled as uncategorized fungi, further studies are recommended for the evaluation of the metabolic potentials of these fungi as there is a possibility of the discovery of new fungi or genes of industrial or environmental applications.

Effects of Continuous Cropping on the Physiochemical Properties, Pesticide Residues, and Microbial Community in the Root Zone Soil of Lycium barbarum

Continuous cropping is a common obstacle limiting the high quality and yield of Lycium barbarum （wolfberry）. To clarify the response of soil characteristics of the wolfberry root zone to continuous cropping years, we systematically determined the physicochemical properties and pesticide residues of soils in the wolfberry root zone with different continuous cropping years. In addition, soil bacterial and fungal communities were characterized using high-throughput sequencing technology. The results were as follows： The content of total salt and imidacloprid in the root zone of wolfberry increased with increasing years of continuous cropping. Compared to that with 2 and 9 years, the total salt content in the root zone of wolfberry with 15 years of continuous cropping increased by 51.97% and 54.33%, respectively, and the imidacloprid content increased by 39.58% and 36.61%, respectively. Alkaline nitrogen and available potassium showed an increasing and then decreasing trend. Compared to that with 2 and 15 years, alkaline nitrogen and available potassium in the root-soil of wolfberry with 9 years of continuous cropping increased by 16.94%-28.09% and 18.31%-18.34%, respectively. The diversity and abundance of bacterial communities and the abundance of fungal communities were higher in the root-soil of wolfberry with 9 years of continuous cropping compared to that with 15 years of continuous cropping. In addition, the increase in continuous cropping years also increased the accumulation of harmful plant pathogens such as Pseudomonas, Arthrobacter, Actinomucor, and Trichoderma in the root zone of L. barbarum. Soil total salinity, organic matter, alkaline hydrolyzable nitrogen, and available potassium were the main factors influencing the distribution of bacterial communities. Soil alkaline hydrolyzable nitrogen, available potassium, and ammonium nitrogen were the main factors influencing the distribution of fungal communities. In addition, the soil bacteria in the root zone of L. barbarum were dominated by metabolic functions； in particular, amino acid metabolism, energy metabolism, and nucleotide metabolism were most abundant in the root soil of wolfberry with 9 years of continuous cropping, whereas the highest abundance of functional genes related to membrane translocation was found in the root-soil of wolfberry with 15 years of continuous cropping. The soil fungi were all dominated by saprophytic trophic types, followed by pathogenic cross-nutrients in the root zone of L. barbarum. In conclusion, long-term continuous cropping induced changes in the soil microenvironment in the root zone of L. barbarum, increased soil residues of harmful pesticides and the enrichment of plant pathogens, and reduced the diversity of soil bacterial and fungal communities. Therefore, it is necessary to control the rate of application of soil nutrients and pesticides in the management of L. barbarum and to carry out deep ploughing and deep tilling in good time, and the turnover of old plants in the cultivation of L. barbarum.

Fungal aerosols over the Northwest Pacific to Arctic Ocean: The influence of air mass and environmental factors

Bioaerosols, prevalent in the atmosphere, serve as carriers for microbe transmission and can also act as Cloud Condensation Nuclei (CCN) and Ice Nuclei (IN), exerting significant influence on cloud microphysics, radiative forcing, precipitation processes, and global climate dynamics. In this study, we conducted a comprehensive study of airborne fungi from the Northwest Pacific to the Arctic Ocean. During the 9th Chinese National Arctic Research Expedition (Chinare, 2018) cruise, total suspended particulate matter (TSP) samples were collected, followed by high-throughput sequencing to determine the microbial community's structure. Ascomycota and Basidiomycota are widespread in marine fungal aerosols along this route, with a notably higher abundance of Epicoccum and Cladosporium in fungal aerosols from the low-latitude Northwest Pacific compared to the high-latitude Arctic Ocean region. The composition of fungal communities depended on air mass transport processes and environmental factors. Long-range transport of terrestrial air masses not only enriches the abundance of fungal aerosols but also increases the relative abundance of dominant genera such as Basidiomycota, Epicoccum and Cladosporium. The knowledge gap about fungal aerosols over the Arctic route from the Northwest Pacific to the Arctic Ocean was filled in part by this work. This study deepens our understanding of how environmental factors and terrestrial air masses influence the composition and distribution of fungal community, offering valuable insights into the interconnections between marine and terrestrial ecosystems and their potential impacts on climate and atmospheric processes.

Response of Soil Fungal Community in Coastal Saline Soil to Short-Term Water Management Combined with Bio-Organic Fertilizer

This study aimed to elucidate the response of soil microbial communities to saline soil amelioration via biological organic fertilizer. A year-long experiment was conducted on coastal saline soil, employing water and fertilizer strategies. Three treatments were compared: dry field (control, CK), paddy field (W), and combined dry and irrigated fields with biological organic fertilizer (BW). Soil DNA was extracted and sequenced using high-throughput methods, revealing significant reductions in soil electrical conductivity (EC) and pH with W and BW treatments. Moreover, the BW treatment notably increased soil organic carbon content by 17.2%, as well as soil urease and alkaline phosphatase activity. Fungal community richness increased, with the BW treatment showing a 36% rise in the ACE index and a 24% increase in the Shannon index, while the Simpson index decreased by 59%. Dominant fungal phyla were Ascomycota, Mortierellomycota, and Basidiomycota, with Basidiomycota prevailing at the genus level. Redundancy analysis (RDA) indicated that soil pH, EC, and organic carbon were key determinants of fungal community distribution, with the BW treatment correlating negatively with pH and salt and positively with soil organic carbon (SOC). Fungal functional groups varied among treatments, with saprophytic fungi predominating, but the BW treatment showed a higher relative abundance of animal pathogenic fungi. In summary, the integration of biological organic fertilizer with flooding ameliorates soil properties and influences the changes in soil fungal community structure and function in the short term. These results could enhance the scientific basis for the efficient utilization and development of saline soil resources in coastal areas.

The Impact of Artificial Restoration of Alpine Grasslands in the Qilian Mountains on Vegetation, Soil Bacteria, and Soil Fungal Community Diversity.

To understand how the soil microbial community structure responds to vegetation restoration in alpine mining areas, this study specifically examines the grassland ecosystem in the Qianmalong mining area of the Qilian Mountains after five years of artificial restoration. High-throughput sequencing methods were employed to analyze soil bacteria and fungi microbial characteristics in diverse grassland communities. Combined with modifications in vegetation diversity as well as soil physicochemical properties, the impact of vegetation restoration on soil microbiome diversity in this alpine mining area was investigated. The findings indicated that the dominant plants were Cyperus rotundus, Carex spp., and Elymus nutans. As the extent of the grassland's restoration increased, the number of plant species, importance values, and plant community diversity showed an increasing trend. The plant functional groups were mainly dominated by Cyperaceae, followed by Poaceae. Plant height, density, plant cover, frequency, and aboveground biomass showed an increasing trend, and soil water content (SWC) increased. While soil pH and soil electrical conductivity (EC) exhibited a declining trend, available phosphorus (AP), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3-N), soil organic carbon (SOC), and soil water content (SWC) showed an increasing trend. The dominant bacterial communities were Actinobacteriota, Proteobacteria, Acidobacteriota, Chloroflexi, Firmicutes, and Gemmatimonadota, while the dominant fungal communities were Ascomycota, Mortierellomycota, Basidiomycota, unclassified_k_Fungi, and Glomeromycota. Significant differences were detected within soil microbial community composition among different degrees of restoration grasslands, with bacteria generally dominating over fungi. SWC, TP, and TN were found to be the main soil physicochemical factors affecting the distribution of soil bacterial communities' structure; however, SOC, TN, and NO3-N were the primary factors influencing the soil distribution of fungal communities. The results of this study indicate that different degrees of vegetation restoration in alpine mining areas can significantly affect soil bacterial and fungal communities, and the degree of restoration has varying effects on the soil bacteria and fungi community structure in alpine mining areas.

Drivers and human impacts on topsoil bacterial and fungal community biogeography across Australia.

Soil microbial diversity mediates a wide range of key processes and ecosystem services influencing planetary health. Our knowledge of microbial biogeography patterns, spatial drivers and human impacts at the continental scale remains limited. Here, we reveal the drivers of bacterial and fungal community distribution in Australian topsoils using 1384 soil samples from diverse bioregions. Our findings highlight that climate factors, particularly precipitation and temperature, along with soil properties, are the primary drivers of topsoil microbial biogeography. Using random forest machine-learning models, we generated high-resolution maps of soil bacteria and fungi across continental Australia. The maps revealed microbial hotspots, for example, the eastern coast, southeastern coast, and westcoast were dominated by Proteobacteria and Acidobacteria. Fungal distribution is strongly influenced by precipitation, with Ascomycota dominating the central region. This study also demonstrated the impact of human modification on the underground microbial community at the continental scale, which significantly increased the relative abundance of Proteobacteria and Ascomycota, but decreased Chloroflexi and Basidiomycota. The variations in microbial phyla could be attributed to distinct responses to altered environmental factors after human modifications. This study provides insights into the biogeography of soil microbiota, valuable for regional soil biodiversity assessments and monitoring microbial responses to global changes.

Characterization of fungal communities in aerosols: Coastal waters vs. open oceans

Bioaerosols have an important influence on both the environment and human health. Current research on bioaerosols more focuses on bacterial aerosols, while the research of fungal aerosols could not be neglected, especially in marine environments. We present a study on the spatial distribution of fungal communities in aerosols over the South Yellow Sea (SYS), the East China Sea (ECS) and the northwestern Pacific (NWP) in autumn, further taking into account the influences of particle size differences and environmental factors. We found that the fungal concentrations at the junction of the South Yellow Sea and the East China Sea (SYS-ECS) were significantly greater than those at the junction of the East China Sea and the NWP (ECS-NWP) and the NWP (NWP1, NWP2, NWP5, and NWP9) (p < 0.05). Spatial differences in the richness and diversity of fungal communities were observed across different sea areas. Additionally, both the concentration and richness of fungal aerosols gradually decreased with increasing off-coast distance, suggesting that the influence of terrestrial sources on fungal aerosols over coastal waters was higher than open oceans. According to CCA (canonical correspondence analysis), the fungal community structures in the northern China marginal seas (NCMS) were influenced by the water-soluble ions F−, NO3−, and Ca2+, which primarily originated from anthropogenic activities, whereas wind speed exerted a significant impact on fungal community structure in the NWP. These results illustrate that the community structures of fungal aerosols depend on sampling site locations, source areas, particle size, and transport mechanisms. This research contributes to the understanding of fungal aerosols over the marine environment and reveals the impacts of environmental factors on fungal aerosols.

Characteristics and Dominant Influencing Factors of the Fungal Community Structure in Soils Co-contaminated with Rare Earth Elements and Heavy Metals

Rare earth elements (REEs) have been listed as emerging pollutants and are often enriched together in soils with heavy metals (HMs), which results in ecological crises. The ecological effects caused by REEs have been attracting increasing amounts of attention, but most studies neglect the synergistic effect of REEs and HMs. The soil fungal community plays an important role in maintaining ecosystem functions, and understanding the fungal community structure and its dominant influencing factors in the co-contaminated soils will help to develop soil remediation strategies that could reduce or remedy the impacts of human production activities on the environment. Currently, the effects of long-term contamination of REEs and HMs on the soil fungal communities remain unclear. The Baotou rare earth tailings dam (Inner Mongolia, China) was used as the area of study, and soil samples co-contaminated with REEs and HMs were collected. Illumina high-throughput sequencing with ITS1 gene amplicons was used to analyze the fungal community diversity and structural characteristics. The results showed that the heterogeneity of soil environmental variables determined the distribution of fungal communities in a small area and constituted its own unique ecological niche in the co-contaminated environment. The fungal community richness and diversity in the co-contaminated soils were significantly lower than those in the uncontaminated soils, and the composition of the fungal community was significantly different. The results of a random forest (RF) analysis showed that TN was the most important factor that affected the fungal community richness and diversity, followed by REEs, Zn, and AK. The results of a canonical correspondence analysis (CCA) showed that Zn was the most important factor that affected the fungal community structure. A variation partitioning analysis (VPA) was performed to quantify the relative contributions of different environmental variables on the changes in fungal community structure, and the analytical results showed that all the detected environmental variables could explain 93.3% of the variation in soil fungal community. The combined effect of soil physicochemical properties and pollution factors (REEs and HMs) accounted for 58.5% of the total variation, and their contribution alone accounted for 13.5% and 21%, respectively. The effects of these pollution factors on the fungal communities were slightly higher than those of the soil physicochemical properties. The synergistic contributions of REEs and HMs were 40.1%, and their individual effects were 21.8% and 17.9%, respectively. Therefore, the soil physicochemical properties, REEs, and HMs regulated the fungal community structure and composition in concert. The synergistic contributions of REEs and HMs were greater than their individual effects, and these results suggest that it is necessary to further strengthen the risk control of the co-contamination of REEs and HMs in the soil environment.

Exploring the temporal dynamics of rumen bacterial and fungal communities in yaks (Bos grunniens) from 5 days after birth to adulthood by full-length 16S and 18S rRNA sequencing.

The rumen of ruminants is inhabited by complex and diverse microorganisms. Young animals are exposed to a variety of microorganisms from their mother and the environment, and a few colonize and survive in their digestive tracts, forming specific microflora as the young animals grow and develop. In this study, we conducted full-length sequencing of bacterial and fungal communities in the rumen of pastured yaks of different ages (from 5 days after birth to adulthood) using amplified sequencing technology. The results showed that the rumen microflora of Zhongdian yaks changed gradually from 5 to 180 days after birth and tended to stabilize at 2 years of age. The rumen of adult yaks was the most suitable for the growth and reproduction of most bacteria. Bactria diversity of the yak rumen increased gradually from 5 days after birth to adulthood. With the growth of yaks, different dominated bacteria were enriched in different groups, but Prevotella remained highly abundant in all groups. The yak rumen at 90 days of age was the most suitable for the growth and reproduction of most fungi, and 90 days of age could be a cut-off point for the distribution of fungal communities. Fungal Thelebolus was the firstly reported in yak rumen and was enriched in the yak rumen of 90 days after birth. The most abundant and balanced fungal genera were found in adult yaks, and most of them were only detected in adult yaks. Our study reported on the rumen bacterial and fungal communities of Zhongdian yaks grazed at different ages and provided insights into the dynamic changes of dominant microflora with yak growth.

Decline in Morel Production upon Continuous Cropping Is Related to Changes in Soil Mycobiome.

The black morel Morchella sextelata (Morchellaceae, Pezizales) is a valuable edible mushroom that can be cultivated on a large scale, but a severe yield decline is observed during continuous cropping. The effect of long-term cropping on soil-borne diseases and the dysbiosis of the microbiome and how these biotic factors affect the morel yield are not well understood. To help fill this knowledge gap, we designed an indoor experiment to investigate the influence of black morel cropping regimes on soil physicochemical properties, richness and distribution of fungal community, and morel primordial production. In this study, we employed rDNA metabarcoding and microbial network analysis to evaluate the effect of non-continuous and continuous cropping regimes on the fungal community during three developmental stages of black morel production, namely, the bare soil mycelium, mushroom conidial, and primordial stages. The results showed that during the first year, M. sextelata mycelium overwhelmed the resident soil fungal community by reducing the alpha diversity and niche breadth of soil fungal patterns by a greater amount compared to the continuous cropping regime, leading to high crop yield of 12.39 ± 6.09/quadrat but less complex soil mycobiome. To sustain continuous cropping, exogenous nutrition bags and morel mycelial spawn were consecutively added to the soil. The additional nutrient input stimulated the growth of fungal saprotrophic decomposers. The degrading activity of soil saprotrophs, including M.sextelata, caused a significant increase in soil nutrient content. This led to an inhibitory effect on the formation of morel primordia, resulting in a sharp decline to 0.29 ± 0.25/quadrat and 0.17 ± 0.24/quadrat, respectively, in the final morel cropping. Our findings provided a dynamic overview of the soil fungal community during morel mushroom production, allowing us to identify beneficial and detrimental fungal taxa in the soil mycobiome involved in morel cultivation. The information acquired from this study can be applied to mitigate the adverse impact of continuous cropping on the yield of black morel.

Changes of Arbuscular Mycorrhizal Fungal Community and Glomalin in the Rhizosphere along the Distribution Gradient of Zonal Stipa Populations across the Arid and Semiarid Steppe.

ABSTRACTArbuscular mycorrhizal fungi (AMF) have been reported to have a wide distribution in terrestrial ecosystems and to play a vital role in ecosystem functioning and symbiosis with Stipa grasses. However, exactly how AMF communities in the rhizosphere change and are distributed along different Stipa population with substituted distribution and their relationships remain unclear. Here, the changes and distribution of the rhizosphere AMF communities and their associations between hosts and the dynamic differences in the glomalin-related soil protein (GRSP) in the rhizosphere soil of seven Stipa species with spatial substitution distribution characteristics in arid and semiarid grasslands were investigated. Along with the substituted distribution of the Stipa populations, the community structures, taxa, species numbers, and alpha diversity index values of AMF in the rhizosphere changed. Some AMF taxa appeared only in certain Stipa species, but there was no obvious AMF taxon turnover. When the Stipa baicalensis population was replaced by the Stipa gobica population, the GRSP tended to decline, whereas the carbon contribution of the GRSP tended to increase. Stipa grandis and Stipa krylovii had a great degree of network modularity of the rhizosphere AMF community and exhibited a simple and unstable network structure, while the networks of Stipa breviflora were complex, compact, and highly stable. Furthermore, with the succession of zonal populations, the plant species, vegetation coverage, and climate gradient facilitated the differentiation of AMF community structures and quantities in the rhizospheres of different Stipa species. These findings present novel insights into ecosystem functioning and dynamics correlated with changing environments.IMPORTANCE This study fills a gap in our understanding of the soil arbuscular mycorrhizal fungal community distribution, community composition changes, and diversity of Stipa species along different Stipa population substitution distributions and of their adaptive relationships; furthermore, the differences in the glomalin-related soil protein (GRSP) contents in the rhizospheres of different Stipa species and GRSP’s contribution to the grassland organic carbon pool were investigated. These findings provide a theoretical basis for the protection and utilization of regional biodiversity resources and sustainable ecosystem development.

Croatian white grape variety Maraština: First taste of its indigenous mycobiota

The indigenous vineyard mycobiota contribute both to wine quality and vineyard sanitary status. Wines made from same grape variety but from different geographical locations are appreciated for their diversity. Because no information on indigenous mycobiota of Croatian grapevines is available, the aim of the present study was to start filling this knowledge gap by characterizing the indigenous mycobiota of Maraština variety. The use of metataxonomic approach has enabled the identification of 25 different fungal genera present on Maraština grape berries collected from 11 vineyards located within the Croatian coastal winegrowing region of Dalmatia (Northern Dalmatia, Dalmatian hinterland, Central and Southern Dalmatia). The substantial regional and local scale differences in their distribution were observed. Overall, Aureobasidium was the dominant genus followed by Cladosporium and Metschnikowia. Botrytis and Plenodomus were associated with the vineyards located in Central and Southern Dalmatia, whereas Pichia was associated with Northern Dalmatia vineyards. The largest abundance of Buckleyzyma, Cladosporium, Eremothecium, Fusarium, Papiliotrema, and Rhodotorula was observed in Dalmatian hinterland. Moreover, data suggested that climate conditions and soil type partially influenced the distribution of fungal communities. The local-scale differences emerged also for the physicochemical characteristics of fresh musts. The high malic acid content supported the development of Metschnikowia, and inhibited Fusarium growth, whereas a positive correlation between Erysiphe and pH values was observed. Sporobolomyces and Cystobasidium were negatively associated with high glucose concentration. The revealing of Maraština indigenous mycobiota provided information on the members of fungal community negatively influencing the grapevine sanitary status as well as those which could be employed in disease biocontrol.

Diversity and structure of soil fungal communities unveil the building history of a burial mound of ancient Japan (Tobiotsuka Kofun, Okayama Prefecture)

Kofuns are burial mounds of ancient Japan (3rd-7th century CE, defined as Kofun Period). The construction history and archaeological significance of Kofuns of the Late Kofun Period (6th-7th century) still need to be characterized. This study dealt with Tobiotsuka Kofun (Okayama Prefecture, Japan) and aimed to investigate if diversity and structure of soil fungal communities, and their relationships with soil characteristics, beyond reflecting present vegetation, may be informative on the construction history of the burial mound. In particular the analyses aimed to verify the supposed presence of a boundary between the original hill and the potential anthropic backfill. Soil fungal communities were characterized by high-throughput sequencing (Illumina MiSeq technology), at the ground and through different archaeological soil layers. Approximately 1.5 × 106 high quality ITS2 sequences, clustered in 1875 OTUs, were obtained from 59 sampling points, distributed inside the burial chamber and on the Kofun external slopes. Heterogeneity and vertical distribution of fungal communities, considered in terms of taxonomic and trophic groups, generally showed a compatible pattern with present-day topographic conditions and vegetation. However, the chemical soil analyses and fungal distribution with depth, in particular that of saprotrophic fungi, cannot be explained by natural soil development and ecological context only, and point towards the presence of a former topsoil layer that was disturbed and at least partially buried by the Kofun construction.

Environmental controls of soil fungal abundance and diversity in Australia's diverse ecosystems

Soil fungi are vital for ecosystem functioning, but an understanding of their ecology is still growing. A better appreciation of their ecological preferences and the controls on the composition and distribution of fungal communities at macroecological scales is needed. Here, we used one of the most extensive continental-scale datasets on soil fungi and modelled the relative abundance of dominant fungal phyla and community diversity in Australian soils from forests, grasslands, shrublands, woodlands, and croplands. Across these diverse ecosystems, the Ascomycota and Basidiomycota dominate Australian soils, and fungal diversity declines as climates become more arid. Climate and the water balance exert dominant control on soil fungal abundance and diversity, mediated by interactions between ecosystem type, the ensuing vegetation and edaphic factors, such as organic matter, clay and iron-oxide mineralogy, pH and nutrients. Soil organic matter and mineralogy, represented by absorptions of visible–near-infrared (vis–NIR) radiation, helped to improve characterisation of the abiotic controls on soil fungi. This better representation of edaphic factors improved the predictability of the models by up to 40%. Our findings contribute to the understanding of fungal ecology at a macroecological scale. They help to appreciate better the links between fungi, soil and the environment, which underpin ecosystem stability and resilience and have implications for developing strategies for preservation, adaptation and mitigation of global change.

Distribution of mycotoxin-producing fungi across major rice production areas of China

Mycotoxin contamination of rice (Oryza sativa), especially that from aflatoxins (AFTs), is one of the greatest chemical hazards to humans and animals. However, few studies have investigated the relationships between fungal communities and mycotoxin contamination of rice grains. In the present study, we collected rice grain samples from 10 provinces in the northeastern (NE), southeastern (SE), and southwestern (SW) regions of China, encompassing the major rice-producing areas of China. The Fungal diversities of rice grains were significantly different among different regions and significantly higher in the SE and SW regions compared to the NE region. Geographic location was highly associated with fungal community alpha and beta diversity differences. Environmental variables determined the distribution of fungal communities, with winter mean temperature (WMT), mean annual precipitation (MAP), harvest mean wind speed (HMW), and grain moisture (GM) being the most important factor shaping the fungal communities, and the higher HMW could significantly reduce the abundance of aflatoxigenic fungi and aflatoxins. The Aspergillus flavus and A. parasiticus were defined as the major AFT-producing fungal taxa observed in the SE and SW region communities. The NE region exhibited a lower risk of AFT contamination due to its much lower prevalence of toxigenic fungi. Furthermore, keystone taxa of co-occurrence network analyses indicated that species belonging to the genera Clonostachys, Cryptococcus, Hannaella, Leptosphaerulina, Leptosphaeria, Phaeosphaeria, Sarocladium, Sphaerulina, Wallemia and Ustilaginoidea exhibited abundances that were negatively correlated with AFT-producing fungal abundances and could potentially inhibit the growth of AFT-producing fungi. The results provide potentially important data for the strategic guidance of local rice grains storage in order to better control toxin contamination and improve grain quality.

On the origin of feces: Fungal diversity, distribution, and conservation implications from feces of small mammals

AbstractFungi are highly diverse, but only a small fraction of the total estimated species have been characterized. Often, the extent of diversity and distribution of fungal communities is difficult or near impossible to assess due to the fact that many fungi are cryptic and persist predominantly hidden within substrates such as soil or plant material. This is particularly true for hypogeous sporocarps, such as truffles and false truffles, which are extremely difficult to survey in a systematic manner. However, hypogeous fungi have evolved traits that make them highly attractive to animals, such as small mammals, which ingest and disperse fungal spores through defecation. Here, samples of feces from 138 small mammal museum vouchers collected in the western United States were assessed for total fungal diversity using a dual‐index metabarcoding approach. Our findings exhibit many identifications within the mushroom‐forming fungi (Agaricomycetidae), with 65 of the 138 samples containing sequences belonging to several species of the false truffle‐forming genus Rhizopogon. Metadata for each collection, such as geospatial coordinates, can be used as a proxy for the presence or absence of Rhizopogon species identified in their feces. Utilizing these proxy data from only a few years of sampling, these records quadrupled the rate of observations of Rhizopogon made over the past 100 years, including some species that have only been recorded once previously. This substantial increase in datapoints has implications for how fungal distributions are interpreted, with direct impact on standard assessment tools for fungal conservation.

Variation in Fungal Community in Grapevine (Vitis vinifera) Nursery Stock Depends on Nursery, Variety and Rootstock.

Grapevine trunk diseases (GTDs) are caused by cryptic complexes of fungal pathogens and have become a growing problem for new grapevine (Vitis vinifera) plantations. We studied the role of the nursery, variety, and rootstock in the composition of the fungal communities in root collars and graft unions of planting material in Catalonia (NE Spain). We compared necrosis and fungal communities in graft unions and root collars at harvest, and then after three months of cold storage. We evaluated combinations of eleven red and five white varieties with four common rootstocks coming from six nurseries. Fungal communities were characterized by isolation and metabarcoding of the ITS2 region. Our data suggests that nursery followed by rootstock and variety had significant effects on necrosis and fungal community structure in graft and root tissues. Within the plant, we found large differences in terms fungal community distribution between graft and root tissues. Graft unions housed a significantly higher relative abundance of GTD-related Operational Taxonomic Units (OTUs) than root collars. More severe necrosis was correlated with a lower relative abundance of GTD-related OTUs based on isolation and metabarcoding analyses. Our results suggest that nurseries and therefore their plant production practices play a major role in determining the fungal and GTD-related fungal community in grapevine plants sold for planting. GTD variation across rootstocks and varieties could be explored as a venue for minimizing pathogen load in young plantations.

Aflatoxins and fungal community distribution during harvesting and processing of Platycladi Semen

This study aimed to analyze aflatoxins content and fungal community distribution in the harvesting and processing of Platycladi Semen, and explore the key link that affects aflatoxins contamination. The related Platycladi Semen samples of different maturity periods(cone non-rupture period, early rupture, and complete rupture period) and different processing periods(before drying, during 2-d drying, during 7-d drying, before and after seed scale removal, before and after peeling, 1 d after color sorting, and 7 d after color sorting) were collected for identifying the fungal community composition on sample surface by ITS amplicon sequencing. Then the content of aflatoxins B_1, B_2, G_1 and G_2 was determined by HPLC-MS/MS. The results showed that during the harvesting of Platycladi Semen from cone non-rupture to complete rupture, aflatoxins were only detected in the seed scale and seed coat, with aflatoxin G_2 in the seed scale and aflatoxin B_1 in the seed coat. During the drying, with the prolongation of drying time, aflatoxins B_1 and G_2 were detected simultaneously in the seed scale, aflatoxin B_1 in the seed coat, and low-content aflatoxin B_1 in the seed kernel. During subsequent processing, the aflatoxin content in seed kernel during subsequent processing was slighted increased. As demonstrated by fungal detection, Aspergillus flavus was not present during the harvesting of Platycladi Semen, but present during the drying and processing. Its content in the seed coat during the drying process was relatively higher. In short, Platycladi Semen should be harvested as soon as possible after it becomes fully mature. Drying process is the key link of preventing aflatoxin contamination. It is advised to build a sunlight room or adopt similar settings, standardize the operations in other processes, and keep the surrounding environment clean to minimize aflatoxin contamination.