The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications

Metagenomic and meta-metabolomic analysis of traditional Korean rice vinegar productions shows a large variability between producers

Cereal vinegars have been used for thousands of years, especially in Asian countries. These vinegars are still produced in a traditional way by a spontaneous, consecutive, alcoholic and acetic acid fermentation process in open vats under non-sterile conditions, which can lead to an unstable and inconsistent flavor and quality. The present study characterized the microbial diversity of complete, traditional Korean rice vinegar productions at two producers (A and B), from steamed rice to rice vinegar, applying high-throughput amplicon-based and shotgun metagenomic sequencing, in combination with meta-metabolomic analysis. Functional analysis based on metagenome-assembled genomes provided insights into the genetic potential of the different microorganisms involved. Producer A used nuruk, a traditional starter, and seed vinegar to start the alcoholic and acetic acid fermentation phases, respectively, which resulted in highly controlled productions even when different fermentation vessels were used. Producer B used only nuruk to start the vinegar productions, and the spontaneous inoculation of acetic acid bacteria did fail in one of the productions. The addition of nuruk resulted in a simultaneous rice starch saccharification and alcoholic fermentation phase characterized by producer-specific moulds, yeasts, and lactic acid bacteria (LAB). During the acetic acid fermentation phase at both producers (a) novel Acetobacter species, related to A. pasteurianus was found. The simultaneous presence of several LAB species made it hard to link them with the production of specific metabolites. Also, the species contributing to ester formation, important for the flavor, was not clear and requires further research.

Gut microbiota-derived butyrate alleviates the impairment of mice intestinal integrity caused by Toxoplasma gondii infection

Chronic infection with Toxoplasma gondii (T. gondii) results in severe damages to the integrity of intestinal barrier, however, both the underlying mechanism and feasible intervention strategies are still little known. Here, we found that both the chronic infection of T. gondii and transplanting gut microbiota from T. gondii-infected mice severely impaired the mice intestinal integrity, which was characterized by significantly decreased thickness of inner mucus layer and down-regulated expression of three tight junction proteins Occludin, ZO-1, and Claudin (p < 0.05). Moreover, T. gondii infection also led to mice intestinal microbiota dysbiosis, especially butyrate-producing bacteria, and significantly changed the expression of several senescence-associated markers, including 6- and 7- fold upregulation for P16, P21, and 6-fold downregulation for Lamin B1 at mRNA levels, and 2-fold downregulation for β-galactosidase at protein levels (p < 0.05). Interestingly, subsequent administration with dietary butyrate could alleviate T. gondii-induced intestinal integrity impairment and cell senescence, revealing a significant increase of the inner mucus layer thickness (p < 0.001), and a remarkable decrease in P16, P21, β-galactosidase expression levels while an upregulation of Lamin B1 expression (p < 0.05). Taken together, our study revealed that T. gondii-induced dysbiosis of gut microbiota, especially butyrate-producing bacteria, contributes to the intestinal impairment, potentially via promoting cell senescence. In addition, administration with the metabolite, butyrate, could be a promising therapeutic measure against T. gondii infection.

Impacts of different plastic residues on soil volatile profiles associated with microbiome dynamics

Plastic pollution poses a significant threat to soil ecosystems, yet the role of volatile organic compounds (VOCs) in plastic degradation is not well-studied. The present research focuses on the impact of polyethylene (PE), polylactic acid (PLA), and poly(butylene-adipate-co-terephthalate) (PBAT) residues on soil in a 12-week long lab-scale aerobic experiment. The study focused on the dynamics of VOC profiles, soil physicochemical properties, and microbial communities. PBAT, known for its biodegradability, produced a distinct VOC profile with hazardous compounds such as 1,3-butadiene, which is consistently associated with cardiovascular diseases and leukemia. Microbial analysis of PBAT revealed distinct bacterial and fungal diversity responses, along with unique KEGG pathway profiles compared to PE and PLA, suggesting its biodegradation process may involve biofilm formation and quorum sensing. Correlation analysis based on the relevant abundance of specific microbes exhibited strong positive correlations, such as Streptomyces with propyne emission and Hydrogenispora with ethylene emission. These results demonstrated distinct biodegradation patterns of various plastics in soil, identified through the combination of VOC detection and microbiome analysis.

Uncharacterized members of the phylum Rozellomycota dominate the fungal community of a full-scale slow sand filter for drinking water production

Slow sand filters (SSFs) for drinking water production are habitats for diverse microbes from multiple domains of life, which are integral to the ability of SSFs to purify water. While cultivation-independent analyses of the prokaryotic communities of SSFs have provided valuable insights, little attention has been paid to fungi inhabiting SSFs. This study characterized the fungal communities in the sand biofilm of one established, one inoculated and one non-inoculated SSF. The removal of the top-layer of sand ("scraping") allowed fungal communities in the top and subsurface layers of sand to be analyzed using amplicon sequencing of the ITS2 region of fungal rRNA genes. The top layers of SSF sand contained fungal communities dominated by phylum Ascomycota (43.5-75.6 %). After scraping, high abundances (>70 %) of phylum Rozellomycota were revealed in the established filter. These fungi were also detected in an inoculated filter, but not in a non-inoculated filter, suggesting potential dispersal to new filters by inoculation. The diverse Rozellomycota sequences potentially represented 6 different order-level clades, with most being related to previously observed Branch03 Rozellomycota. Their roles in SSF function are unknown but may be related to the removal of indicator bacteria as this phylum includes potential parasites of grazing eukaryotes. Fungi known to constitute microbial risk or contribute to micropollutant biodegradation were in low abundance and only sporadically detected. Lifestyle traits could be predicted for 61.8 % of fungi in the SSF biofilm; most of these were saprotrophic microfungi or yeasts. This study presents an overview of the composition of fungal communities in full-scale SSF, and their potential interactions with water quality. It also highlights the need for more knowledge regarding the ecology of "dark matter"-fungi, such as Rozellomycota, and presents an accessible and societally relevant environment for future research of these microbes.

Response of abundant and rare microbial species to 40-year long-term fertilization practices irrespective of bulk and rhizosphere soils

Fertilization practices could exert significant influence on the diversity, interactions, and functions of soil microorganisms. However, little is known about how specific microbial groups and their interactions adapt or evolve in response to agricultural practices, especially long-term mineral fertilization. Here we explored the community assembly process shaping the microbial community and co-occurrence networks of abundant and rare groups based on a high-throughput sequencing approach in a field experiment with 40 years of mineral nitrogen (N) and phosphorus (P) fertilization. The results indicated that fertilization (25-51 %) had a strong impact on microbial community structure, while little difference were found between rhizosphere and bulk soils irrespective of abundant and rare microbial groups. Deterministic processes primarily govern the assembly of both abundant and rare bacterial and fungal taxa. Random forest analysis revealed that soil pH and N-related nutrients (i.e. nitrate nitrogen (NO3--N), dissolved organic nitrogen (DON) and ammonium nitrogen (NH4+-N)) were the key factors influencing microbial community structure. Structural equation modeling and mantel test further indicated that deterministic factors, particularly soil pH, influence co-occurrence network complexity by modulating the microbiome. Overall, these findings provide insights into factors shaping the microbial community assembly and co-occurrence network dynamics in agroecosystems subjected to long-term fertilization.

Ecological restoration reduces greenhouse gas emissions by altering planktonic and sedimentary microbial communities in a shallow eutrophic lake

Ecological restoration is a promising approach to alleviate eutrophication. However, its impacts on greenhouse gas (GHG) emissions and the underlying microbial mechanisms in different habitats of lakes remain unclear. To address this knowledge gap, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes at both water-air and sediment-water interfaces of eutrophic (Caohai) and restored area (Dapokou) of Dianchi Lake, a typical eutrophic lake in China. Meanwhile, we investigated the responses of planktonic and sedimentary bacterial and fungal communities by high-throughput sequencing. Our results indicated that 6 years of ecological restoration significantly reduced CO2 and N2O fluxes by 1.0-3.6 and 2.2-2.8 folds respectively, with more pronounced variations at the water-air interface than the sediment-water interface. Ecological restoration also shifted the structures of planktonic bacterial and fungal communities remarkably, leading to a significant reduction in the relative abundances of Actinobacteriota (by 70.94%), Bacteroidota (by 61.65%), Planctomycetota (by 74.18%) and Chytridiomycota (by 95.44%). Correlation analyses further suggested that GHG fluxes at the water-air interface were significantly correlated with planktonic microbial community composition (P < 0.05), and the significant reduction of CO2 and N2O fluxes under ecological restoration could be attributed to the decreased abundances of organic matter decomposers (such as hgcI_clade, Sporichthyaceae and Acidibacter) and increased abundances of autotrophs (such as Hydrogenophaga and Cyanobium_PCC-6307) in water. Collectively, our findings verify the importance of ecological restoration in reducing GHG emissions in inland lake ecosystems, providing new insights for addressing global climate change and advancing carbon neutrality.

Mucosal immune responses and intestinal microbiome associations in wild spotted hyenas (Crocuta crocuta)

Little is known about host-gut microbiome interactions within natural populations at the intestinal mucosa, the primary interface. We investigate associations between the intestinal microbiome and mucosal immune measures while controlling for host, social and ecological factors in 199 samples of 158 wild spotted hyenas (Crocuta crocuta) in the Serengeti National Park, Tanzania. We profile the microbiome composition using a multi-amplicon approach and measure faecal immunoglobulin A and mucin. Probabilistic models indicate that both immune measures predicted microbiome similarity among individuals in an age-dependent manner. These associations are the strongest within bacteria, intermediate within parasites, and weakest within fungi communities. Machine learning models accurately predicted both immune measures and identify the taxa driving these associations: symbiotic bacteria reported in humans and laboratory mice, unclassified bacteria, parasitic hookworms and fungi. These findings improve our understanding of the gut microbiome, its drivers, and interactions in wild populations under natural selection.

Fungi as a Critical Component of Lake Microbiota in Response to Cyanobacterial Harmful Algal Blooms

Cyanobacterial Harmful Algal Blooms (CyanoHABs) pose a growing threat to lake ecosystems. While microbial communities constitute the resilient power of lake ecosystems to CyanoHAB disturbances, the role of fungi remains underexplored. Here, the dynamics of size-fractionated fungal and associated bacterial communities were tracked across the peak and decline stages of a CyanoHAB event in shallow subtropical Lake Taihu. The results revealed that the composition of fungal and bacterial communities in separated size fractions varied between bloom stages, with enrichment patterns likely influenced by their reliance on algal-derived nutrients. Null model-based analysis revealed a shift in fungal community assembly, from dominance by dispersal limitation (44%) and drift (30%) at the peak stage to increased homogeneous selection (44%) at the early decline stage, whereas bacterial communities remained predominantly shaped by stochastic processes, highlighting their distinct responses to cyanobacterial biomass decomposition. Comparative topological analysis of microbial co-occurrence networks showed strengthened cross-kingdom fungi-bacteria interactions as the bloom declined, especially within decomposing cyanobacterial colonies, facilitating nutrient cycling and accelerating cyanobacterial biomass removal. These findings led to a conceptual model proposing fungi as critical members of the freshwater microbiome in eutrophic lakes, driving biogeochemical cycling and potentially contributing to the resilience of the lake ecosystem against CyanoHABs.

Morphological and molecular identification of fungi isolated from spoilt apples in Ota metropolis

Spoilage of apples continues to be a significant issue in the fruit industry. This study aimed to isolate and identify fungal species on deteriorated apples collected from three different locations in Ota market, Ota, Ogun State, Nigeria. A total of eighteen (18) samples of red delicious and Granny Smith apples with obvious spoilage were collected, and their surfaces were sterilized using 85% ethanol. After that, the samples were cultivated on potato dextrose agar (PDA) supplemented with 30 mg/l of chloramphenicol, and incubated at 30 °C for five to seven days. From the subcultures of the primary plates, pure fungal cultures were obtained and were identified by morphological characterization and internal transcribed spacer (ITS1/ITS4) gene method. Ten fungi that cause spoilage in apples have been identified and grouped into six distinct classes. Among the 40 isolates, the most common one was Trametes polyzona strain MT9, accounting for 27.5% of the total isolates. The second most prevalent isolate was Geotrichum candidum strain MT10, with six isolates, representing 15% of the total. The least frequent was Fusarium sp. strain MT3, with only one isolate, amounting to 2.5%. It was in this connection, that a sequence analysis of the ITS regions of the nuclear-encoded rDNA was conducted, revealing significant alignments with Aspergillus sp., Lasiodiplodia theobromae, Curvularia aeria, and Trametes polyzona. This research investigation sought to elucidate the relationships between specified species, yielding a biocontrol strategy for mitigating fruit deterioration and conserving quality.

Severe drought impacts tree traits and associated soil microbial communities of clonal oaks

BACKGROUND

Biotic and abiotic factors, including plant age, soil pH, soil organic matter concentration, and especially water availability, significantly influence soil microbial populations and plant characteristics. While many ecosystems are adapted to occasional droughts, climate change is increasing the frequency and severity of drought events, which negatively impacts plant productivity and survival. Long-lived, drought-sensitive tree species such as Quercus robur are particularly vulnerable to water shortages. Drought also alters soil microbial communities, reducing and reshaping microbial diversity, biomass, and activity, which can in turn disrupt key ecosystem functions. The objective of this study was to investigate the effects of natural drought conditions on soil physicochemical variables, plant traits and microbial communities of the oak clone DF159 in Central Germany. Our research focuses on two study sites, Bad Lauchstädt and Kreinitz, which differ in soil water retention capacity. Data collection spans two periods: before and after a severe drought in 2018. Oak traits and environmental data was collected from 2011 to 2023 covering two oak time series with trees planted annually between 2010 and 2019. Microbial communities were analyzed every second year between 2015 and 2021 around trees representing five different ages.

RESULTS

We found that plant traits, including apical growth, branch elongation and number of shoot flushes, were positively correlated with precipitation and relative humidity. Although the study sites differed in oak leaf number per shoot flush and number of shoot flushes, the 2018 drought negatively impacted all measured plant traits, regardless of sites. Soil bacterial richness and diversity declined at both study sites, independent of plant age, while fungal richness specifically increased in Bad Lauchstädt, which has a higher water-holding capacity, following the drought event. Bacterial community composition was more strongly affected by drought than fungal communities, whereas the latter was more responsive to plant age than bacterial communities.

CONCLUSIONS

Given their strong functional links during drought, interactions among vegetation, microbial communities, and soil functioning may ultimately influence major ecosystem services. Bacterial communities were particularly sensitive to drought, while fungal communities exhibited greater resistance, suggesting their potential role in supporting plant survival under drought stress. These findings highlight the risk that prolonged drought may cause irreversible shifts in microbial communities, with significant implications for soil functions and plant-microbe interactions.

Mycorrhizal Fungi Influence on Mature Tree Growth: Stronger in High-Nitrogen Soils for an EMF-Associated Tree and in Low-Nitrogen Soils for Two AMF-Associated Trees

The plant-mycorrhizal fungi relationship can range from mutualistic to parasitic as a function of the fungal taxa involved, plant ontogeny, as well as the availability of resources. Despite the implications this relationship may have on forest carbon cycling and storage, we know little about how mature trees may be impacted by mycorrhizae and how this impact may vary across the landscape. We collected growth data of two arbuscular mycorrhizal fungi (AMF)-associated tree species, Acer rubrum and A. saccharum, and one ectomycorrhizal fungi (EMF)-associated tree species, Quercus rubra, to assess how the mycorrhizal fungi-plant association may vary along a gradient of nitrogen (N) availability. Individual assessments of fungal taxa relative abundances showed non-linear associations with tree growth; positive associations for the two AMF-associated trees were mostly under low N, whereas positive to neutral associations for the EMF-associated tree mainly took place at high N. Only A. rubrum exhibited greater tree growth with its tree soil-specific mycorrhizal community when compared with predictions under a random mycorrhizal soil community. Because mycorrhizal fungi are likely to mediate how plants respond to warming, increasing levels of N deposition and of atmospheric CO2, understanding these relationships is critical to accurately forecasting tree growth.

Partial mycoheterotrophy in Apostasia wallichii, an early-diverging Asian tropical orchid

All orchids exhibit mycoheterotrophy during their early development stages, which predisposes certain species to retain this nutritional mode into adulthood. Consequently, many orchids adopt partial mycoheterotrophy, a mixotrophic strategy combining carbon acquisition through both autotrophy and mycoheterotrophy. However, whether this strategy represents an ancestral trait remains contested. This study examines the fungal symbionts and nutritional strategies of the early-diverging orchid Apostasia wallichii and a sympatric, photosynthetic orchid, Cystorchis variegata, in tropical Asia (Sabah, Malaysian Borneo). Specifically, we explored their potential nutritional modes and mycobionts by analysing δ13C and δ15N isotopic profiles and employing high-throughput DNA sequencing. Community profiling via metabarcoding revealed that the A. wallichii individuals investigated were predominantly associated with putatively saprotrophic Botryobasidium fungi, while C. variegata was simultaneously associated with non-ectomycorrhizal rhizoctonias, saprotrophic non-rhizoctonia fungi, and ectomycorrhizal fungi. Additionally, stable isotope analysis showed that both A. wallichii and C. variegata were significantly enriched in 13C and 15N compared to co-occurring autotrophic plants, indicating partial mycoheterotrophy. Our findings, particularly the discovery of partial mycoheterotrophy associated with non-ectomycorrhizal fungi in A. wallichii, suggest that partial mycoheterotrophy in green orchids may be more widespread than previously believed and could represent an ancestral trait intrinsic to orchids.

Green, variegated, and albino Cremastra variabilis provide insight into mycoheterotrophic evolution associated with wood-decaying fungi

With approximately 31,000 species, orchids begin life as mycoheterotrophs, relying on fungi to meet their carbon demands. Notably, some green orchids retain the ability to acquire carbon through fungal associations (partial mycoheterotrophy) and occasionally produce albino or, more rarely, variegated phenotypes. A linear relationship has been observed between leaf chlorophyll content and dependence on fungal-derived carbon, particularly in orchids associated with ectomycorrhizal (ECM) fungi, but whether such plasticity is similarly robust among orchids associated with non-ECM fungi remains underexplored. Here, we focused on the green, variegated, and albino forms of Cremastra variabilis, which likely lack ECM associations, to investigate (i) whether the degree of mycoheterotrophy, indicated by 13C enrichment, correlates with chlorophyll content, and (ii) whether nutritional shifts align with changes in plant structure and mycorrhizal communities. Our results show that rhizoctonia fungi were dominant in green individuals with high chlorophyll levels and lacking coralloid rhizomes, whereas albino and most variegated individuals possessing coralloid rhizomes primarily associate with Psathyrellaceae fungi. Chlorophyll content and carbon stable isotope abundances were negatively correlated, indicating a gradient of increasing mycoheterotrophy from green to albino forms in individuals with coralloid rhizomes. In conclusion, C. variabilis maintains a flexible balance between photosynthesis and mycoheterotrophy, likely shaped by its subterranean morphology and fungal associations, with wood-decaying Psathyrellaceae fungi providing greater support for mycoheterotrophic nutrition than rhizoctonia fungi.

Fermentative Yeast Diversity at the Northern Range Limit of Their Oak Tree Hosts

Fermentative yeasts play important roles in both ecological and industrial processes, but their distribution and abundance in natural environments are not well understood. We investigated the diversity of yeasts at the northern range limit of their oak tree hosts (Quercus spp.) in Sweden, and identified climatic and ecological conditions governing their distribution. Yeasts were isolated from bark samples from 28 forests and identified to the species level using DNA metabarcoding. Most communities were dominated by species in the Saccharomycetaceae family, especially by species of Saccharomyces, Kluyveromyces and Pichia. Each genus showed a distinct latitudinal and longitudinal distribution, and both temperature and precipitation metrics predicted significant variation in their abundance. Consistent with this, laboratory assays revealed significant effects of temperature on the growth of strains collected from different longitudes and latitudes. We found that older trees harbour more diverse and more balanced fermentative yeast communities with more evenly distributed species abundances. Communities across trees were more similar when sharing a common dominant species. This work provides a baseline for future studies on the impact of climate change on the fermentative yeast biodiversity of temperate forests in northern latitudes and contributes to a growing collection of wild isolates for potential biotechnological applications.

Assessing population exposure to airborne fungi in the UK over one year using high-throughput sequencing (HTS) metabarcoding methods

Airborne fungi are significant contributors to allergic and infectious disease. While microscopy remains the primary method for fungal identification, high-throughput sequencing (HTS) enables untargeted analysis of a much wider range of environmental taxa. This study used HTS to better characterise airborne fungal composition over a 12-month period in two UK locations, the city of Leicester in central England and a rural site in Chilton (Oxfordshire) approximately 115 km further south. Air samples were collected over a year. A subset of 240 samples (120 per location) were analysed by HTS with a combined internal transcribed spacer region (ITS2) and D1/D2 region of the large subunit (LSU) metabarcoding approach. With statistical imputation a representative 12-month dataset was created. Differences in fungal diversity and composition were explored, incorporating meteorological data. HTS analysis identified 272 fungal genera across locations and seasons, approximately 4-fold more than in other studies using traditional microscopy methods. Fungal diversity, richness and composition at the two locations were broadly similar with some taxa-specific differences likely reflecting land-use types (urban vs rural) and/or local meteorological variables. In particular, air temperature and precipitation significantly influenced fungal composition. This study demonstrates the value of HTS for characterising airborne fungi. While it does not provide absolute quantitation, HTS could be used as a screening tool to identify novel associations between fungal exposure and health outcomes, and should be used in combination with quantitative methods, such as microscopy and quantitative PCR (qPCR). Greater spatial and temporal understanding of the wide range of airborne fungal exposure is crucial for exploring associated health impacts and developing improved public health interventions and alert systems for susceptible individuals.

The diversity of prokaryotes and fungi hosted in crude oils

The diversity of prokaryotes and fungi in crude oils has not been understood clearly, though unique microbial communities may be hosted in crude oil. This study investigated the chemical compositions and microbial communities of crude oils from Henan, Bamianhe, and Jianghan oilfields of China. Statistical analysis revealed significant variations of both prokaryotic and fungal communities (P < 0.05) within different oilfields and oils with different biodegradation levels. Diversity analysis showed little difference in prokaryotic, but a significant difference in fungal (P < 0.05). Prokaryotic diversity was higher in heavily biodegraded oils than those in unaltered and slightly biodegraded oils; the opposite was true for fungal diversity (P < 0.05). Moreover, thermophilic prokaryotes were detected mainly in biodegraded heavy oils produced by the practice of thermal recovery from Henan and Bamianhe oilfields, and halophilic prokaryotes were detected mainly in oils from sandstone reservoirs containing hypersaline formation water from Jianghan Oilfield. Accordingly, microbial communities in oils are affected by oil biodegradation, extraction practices, and natural environments of native inhabitants in subsurface petroleum reservoirs.IMPORTANCEThe biological activities of endogenous microorganisms in crude oil play an important role in the production and development of crude oil. Although there have been many microbiological investigations of crude oil-contaminated sites, our understanding of the phylogenetic diversity, metabolic capabilities, and community dynamics of microbial communities within crude oil is far from complete. In this paper, the prokaryotic and fungal communities of three oil fields in different regions of China were analyzed, and several factors affecting microbial degradation were further identified. This study provides a new direction for the subsequent investigation of microbial activities inside crude oil.

Unlocking the agro-physiological potential of wheat rhizoplane fungi under low P conditions using a niche-conserved consortium approach

Plant growth-promoting fungi (PGPF) hold promise for enhancing crop yield. This study delves into the fungal diversity of the wheat rhizoplane across seven Moroccan agricultural regions, employing a niche-conserved strategy to construct fungal consortia (FC) exhibiting higher phosphorus (P) acquisition and plant growth promotion. This study combined culture-independent and culture-dependent methods exploring taxonomic and functional diversity in the rhizoplane of wheat plants obtained from 28 zones. Twenty fungal species from eight genera were isolated and confirmed through internal transcribed spacer (ITS) Sanger sequencing. P solubilization (PS) capacity was assessed for individual species, with Talaromyces sp. (F11) and Rhizopus arrhizus CMRC 585 (F12) exhibiting notable PS rates, potentially due to production of organic acids such as gluconic acid. PGPF traits and antagonism activities were considered when constructing 28 niche-conserved FC (using isolates from the same zone), seven intra-region FC (different zones within a region), and one inter-region FC. Under low P conditions, in planta inoculation with niche-conserved FC (notably FC14 and FC17) enhanced growth, physiological parameters, and P uptake of wheat, in both vegetative and reproductive stages. FC14 and FC17, composed of potent fungi such as F11 and F12, demonstrated superior plant growth benefits compared with intra- and inter-region constructed FC. Our study underscores the efficacy of the niche-conserved strategy in designing synthetic fungal community from isolates within the same niche, proving significant agro-physiological potential to enhance P uptake and plant growth of wheat.

Altered precipitation and nighttime warming reshape the vertical distribution of soil microbial communities

Soil depth determines microbial community composition. Yet, it remains largely unexplored how climate changes affect the vertical distribution of soil microbial communities. Here, we investigated the effects of altered precipitation and nighttime warming on microbial communities in the topsoils (0-20 cm) and subsoils (20-50 cm) of a temperate grassland in Inner Mongolia, China. As commonly observed under nutrient scarcity conditions, bacterial and fungal α-diversity and network complexity decreased with soil depth. However, protistan α-diversity and network complexity increased, which was attributed to less niche overlap and smaller body size. Strikingly, the slopes of linear regressions of microbial α-diversity/network complexity and soil depth were all reduced by altered precipitation. Microbial community composition was significantly influenced by both depth and reduced precipitation, and to a lesser extent by nighttime warming and elevated precipitation. The ribosomal RNA gene operon (rrn) copy number, a genomic proxy of bacterial nutrient demand, decreased with soil depth, and the percentages of positive network links were higher in the subsoil, supporting the "hunger game" hypothesis. Both reduced precipitation and nighttime warming decreased the rrn copy number in the subsoils while increasing the percentages of positive links, enhancing potential niche sharing among bacterial species. The stochasticity level of bacterial and fungal community assemblies decreased with soil depth, showing that depth acted as a selection force. Altered precipitation increased stochasticity, attenuating the depth's filtering effect and diminishing its linear relationship with microbial diversity. Collectively, we unveiled the predominant influence of altered precipitation in affecting the vertical distribution of soil microbial communities.IMPORTANCEUnderstanding how climate change impacts the vertical distribution of soil microbial communities is critical for predicting ecosystem responses to global environmental shifts. Soil microbial communities exhibit strong depth-related stratification, yet the effects of climate change variables, such as altered precipitation and nighttime warming, on these vertical patterns have been inadequately studied. Our research uncovers that altered precipitation disrupts the previously observed relationships between soil depth and microbial diversity, a finding that challenges traditional models of soil microbial ecology. Furthermore, our study provides experimental support for the hunger game hypothesis, highlighting that oligotrophic microbes, characterized by lower ribosomal RNA gene operon (rrn) copy numbers, are selectively favored in nutrient-poor subsoils, fostering increased microbial cooperation for resource exchange. By unraveling these complexities in soil microbial communities, our findings offer crucial insights for predicting ecosystem responses to climate change and for developing strategies to mitigate its adverse impacts.

Identifying rhizosphere bacteria and potential mechanisms linked to compost suppressiveness towards Fusarium oxysporum

BACKGROUND

Soilborne fungal phytopathogens pose a significant threat to global food security. While chemical control remains an effective method for managing these pathogens, increasing regulations due to health and environmental concerns, along with rising fungicide resistance, have restricted their use, underscoring the urgent need for sustainable alternatives. The use of compost to enhance soil fertility and suppress plant diseases is well documented. Several studies have underlined the role of microorganisms in disease suppression, but the mechanisms facilitating this disease suppression remain unclear. We evaluated the impact of compost amendment on the composition and functional capacity of the rhizosphere microbiome in cucumber plants (Cucumis sativus) inoculated with Fusarium oxysporum f. sp. radicis-cucumerinum (FORC) under controlled greenhouse conditions using amplicon sequencing, shotgun metagenomic and culture-based techniques.

RESULTS

Compost amendment significantly reduced FORC-induced disease in cucumber relative to non-amended treatments. While FORC inoculation resulted in significant shifts in microbial (bacterial and fungal) community composition in the rhizosphere of non-amended plants, this phenomenon was substantially less pronounced in the rhizosphere of compost-amended plants. Specifically, compost amendment sustained the presence of Actinomycetota (Streptomyces, Actinomadura, Saccharomonospora, Pseudonocardia, Glycomyces, Thermobifida) and Bacillota (Planifilum, Novibacillus) in FORC inoculated plants, that diminished significantly in inoculated plants without compost. These taxa contained a myriad of non-ribosomal peptides and polyketides synthetases biosynthetic gene clusters (BGCs) with putative antimicrobial and iron-chelating functions. We successfully isolated two Streptomyces strains from FORC-suppressing compost amended rhizospheres that were almost identical to the Streptomyces bin2 (99% ortho ANI) metagenome assembled genome identified in the shotgun metagenome analysis. These strains produced extracellular metabolites that inhibited growth of FORC in-vitro and contained BGCs that encode for compounds with potential antimicrobial capacity.

CONCLUSIONS

Based on results presented in this study, we demonstrate that compost alleviates FORC-induced dysbiosis of the rhizosphere microbiome, maintaining abundance of specific bacterial taxa. These bacterial groups may contribute to disease suppression through a myriad of mechanisms including iron chelation and production of fungal antagonizing secondary metabolites.

Lactobacillus Restructures the Micro/Mycobiome to Combat Inflammation-Mediated Right Ventricular Dysfunction in Pulmonary Arterial Hypertension

BACKGROUND

Inflammation suppresses right ventricular (RV) function in pulmonary arterial hypertension (PAH). In particular, we showed GP130 (glycoprotein-130) signaling promotes pathological microtubule remodeling and RV dysfunction in rodent PAH. Emerging data demonstrate the intestinal microbiome regulates systemic inflammation, but the impact of modulating the gut microbiome on the GP130-microtubule axis in RV failure is unknown.

METHODS

Two weeks following monocrotaline injection, rats were administered daily Lactobacillus rhamnosus (4×107 colony-forming units) via oral gavage for 10 days. Next-generation metagenomics and internal transcribed spacer 2 sequencing delineated fecal bacterial and fungal compositions. SomaScan proteomics measured levels of 7596 serum proteins. RV immunoblots quantified protein abundances. Light or super resolution confocal microscopy assessed RV, lung, and jejunal morphology. Echocardiography and invasive closed-chest pressure-volume loops evaluated PAH severity and RV function. The relationship between Lactobacillus abundance and RV function was assessed in 65 patients with PAH.

RESULTS

Lactobacillus administration restructured both the intestinal micro- and mycobiome. The alteration in the gut ecosystem improved intestinal health as demonstrated by increased jejunal villus length and glycocalyx thickness and diminished intestinal permeability biomarkers. Serum proteomics revealed Lactobacillus modulated systemic inflammation and decreased circulating GP130 ligands. Lactobacillus-mediated suppression of GP130 signaling blunted pathological microtubule remodeling in RV cardiomyocytes. Microtubule-associated phenotypes, including RV cardiomyocyte and nuclear hypertrophy, transverse tubule integrity, and connexin-43 localization, were all corrected with Lactobacillus. These cellular changes manifested as improved RV function despite no significant alteration in PAH severity. Finally, patients with PAH and detectable fecal Lactobacillus had superior RV function despite similar mean pulmonary arterial pressure and pulmonary vascular resistance as compared with those without detectable Lactobacillus.

CONCLUSIONS

Lactobacillus supplementation restructures the gut micro/mycobiome, restores intestinal health, dampens systemic inflammation, and reduces GP130 ligands and associated RV cardiomyocyte microtubule remodeling. These data identify a novel microbiome-inflammation-microtubule axis that has therapeutic relevance for RV dysfunction.

Soil and its microbiome in translocated meadows in the context of habitats in the receptor area

Turf translocation, which is undertaken to mitigate the destruction of valuable habitats, can challenge the soil biota. We investigated translocated protected Molinion meadows in the context of the surrounding environments. Soil and soil microorganisms were examined in meadows translocated four years earlier to a habitat garden in recycled land. Neighbouring habitats, comprised of woodland, cropland and fallow, represented the receptor area, while meadows that remained near the donor area were treated as reference areas. The soil moisture, compaction, reactivity and nutrient availability were examined. The microbial properties studied included taxon-specific markers for a quantitative PCR and Fatty Acid Analysis, N transformation (nitrification potential and ammonia oxygenase gene quantification), as well as the composition and diversity of bacteria, archaea, fungi and protists through soil DNA metabarcoding. The translocated soils were more compacted and had smaller water retention, which impacted the soil communities. A switch from N immobilisation to ammonification and a high diversity of fungi, including a greater richness of saprotrophic and symbiotrophic species occurred, with a higher relative abundance of Ascomycota. Amendments in Stramenopila, Chlorophyta and Alveolata communities were present. A low ratio of ammonia oxidising archaea and bacteria (AOA:AOB; 0.4 translocated vs. 4.9 reference) indicated a degradation of the wet meadow status, which created a suitable environment for copiotrophs. The initial increase in biodiversity pointed out habitat deterioration leading to the loss of specific, protected communities. The use of 'omics' was a sensitive indicator of changes that occurred at the level of the microbiome structure rather than the biomass.

The impact of polyvinyl chloride microplastics on carbon and nitrogen cycling in peat-forming environments: relevance of the filler additive calcium carbonate (CaCO3)

Peat-forming wetlands (PFW) are crucial in the global C-cycle, yet they are increasingly threatened by various anthropogenic pressures, including microplastic (MP) pollution. We investigate the impacts of polyvinyl chloride (PVC) and its additive, calcium carbonate (CaCO3) on organic matter (OM) degradation in PFW. We conducted two experiments: first, by mixing peat soil with increasing concentrations of crushed sanitary PVC-MP (0.3 %, 3 %, and 30 %) and second, by assessing the role of CaCO₃ in modulating these impacts. Our findings revealed significant alterations in peat chemical properties largely mediated by CaCO3 (i.e. increased pH, and Ca2+, Mg2+, K+ concentrations). PVC-MP increased carbon dioxide (CO2) and methane (CH4) production, as well as dissolved organic carbon release. CaCO3 may have enhanced CO2 release through its dissolution and contributed to CH4 production as a C source for a more diverse and active methanogenic community (higher mcrA gene abundance). Shifts in microbial community composition (e.g. reduction of Acidobacteriae and increase in active fermenters, such as Clostridia) and metabolism (higher lignin-like compounds degradation and P-uptake activity but lower activity of labile-C degrading enzymes) also contributed in the C-cycle alterations. PVC-MP enhanced denitrification (narG gene abundance) but reduced relative proportion of the ammonia-oxidizing archaea Nitrososphaeria, leading to inhibition of nitrification. The effects of PVC-MP were concentration-dependent, with CaCO₃ strongly influencing on the C cycle, while its impact on the N cycle was only partial, suggesting potential effect of other additives, such as plasticisers. Overall, our results highlight a significant disruption of microbial processes due to MP pollution, leading to increased greenhouse gas emissions and significant implications on the role of PFW as global C-sinks.

The gut microbiome and metabolome in children with a first febrile urinary tract infection: a pilot study

BACKGROUND

Urinary tract infection (UTI) is a common bacterial infection in the pediatric population. Febrile urinary tract infection (fUTI) can lead to severe complications such as urosepsis as well as kidney scarring, chronic kidney disease, and systemic hypertension. Recent research supports the hypothesis that dysbiosis of the microbiome may play a role in the pathogenesis and development of fUTI in infants. Our main aim was to compare the shift in gut microbiota composition between children with the first fUTI and controls.

METHODS

We conducted an observational study with 17 children with the first fUTI compared to 18 healthy controls. We performed analysis of the gastrointestinal microbiome and measurements of metabolites in stool and urine.

RESULTS

In the gut microbiome, we found significant differences with lower α-diversity the Shannon index) and significantly lower relative abundance of probiogenic bacteria (short-chain fatty acids (SCFA)) in children with the first episode of fUTI before the start of antibiotic therapy. Furthermore, our findings confirm that the length of breastfeeding has significant influence on gut microbiota composition, reducing pathogenic bacteria and enhancing beneficial taxa. Shannon diversity, duration of breastfeeding, and specific taxa, particularly Faecalibacterium and Escherichia, emerged as strong predictors linked to the development of fUTI.

CONCLUSIONS

This study demonstrates that gut microbiome changes are associated with the onset of fUTI in children. Machine learning models identified Shannon index, specific bacterial taxa, and breastfeeding as strong predictors of fUTI. The study highlighted the potential role of the gut microbiome in preventing fUTI.

Land Use Types Drive the Distinct Patterns of Bacterial and Fungal Communities in Soils from the Semi-arid Area

Land types and ways of utilization significantly influence soil microbial communities in arid and semi-arid regions, which are vital for nutrient cycling and ecosystem functionality. In this study, the soil bacterial and fungal communities of five land types, including natural grasslands, farmlands, artificial grasslands, uncultivated lands, and riverbeds in the semi-arid lower reaches of the Heihe River, China, were investigated. Farmlands exhibited the highest bacterial Chao1 richness and Shannon diversity, while uncultivated soils had the lowest bacterial Chao1 richness. Fungal diversity was highest in uncultivated soils compared to farmlands. Principal coordinate analysis (PCoA) showed distinct microbial community structures across land types, with Actinobacteria, Proteobacteria, Firmicutes, and Chloroflexi dominating bacterial communities, and Ascomycota and Basidiomycota dominating fungal communities. Life history strategies revealed distinct patterns between bacterial and fungal communities within farmland soils and artificial grassland soils. Microbial community assembly in natural grasslands was primarily deterministic, with limited stochastic influence, while farmlands exhibited mixed assembly processes. Co-occurrence network analysis showed more stable and cooperative microbial networks in natural grasslands, while farmland networks were more competitive and reliant on key species. These findings provide important insights into the role of land use in shaping microbial diversity and ecosystem function, offering guidance for sustainable land management in semi-arid oasis regions.

Urban soils immobilize harmful microbes and antibiotic resistance genes

Exposure to harmful microbiomes and antibiotic resistance genes (ARGs) can negatively affect human health. However, the contribution of vegetation and soils to the airborne microbiota transferred indoors (AMTI) remains unclear. We used our newly-developed airborne microbial sampler (VenTube) to collect AMTI samples from 72 neighborhoods in Shanghai. The AMTI sampling coincided with simultaneous adjacent phyllosphere and soil microbes. We characterized the microbial communities using next-generation sequencing and quantitative PCR, and employed traceability analysis to identify the sources of AMTI. Our findings revealed that both bacterial and fungal communities in AMTI predominantly originated from phyllosphere, which was estimated to contribute up to 52.3 % and 67.2 % of the bacterial and fungal communities, respectively. Notably, there was extensive co-transfer of potential human pathogens (PHP) between phyllosphere microbes and AMTI. Surprisingly, although the soil harbored higher levels of PHP and respiratory diseases (RDs)-associated ARGs than AMTI, it contained fewer RDs-associated microbes overall. Furthermore, soil sulfur enrichment due to an increase in Ligustrum trees influenced the release of RDs-associated microorganisms from the soil. Collectively, our study emphasizes that the elevated levels of RDs-associated microbes in AMTI primarily derived from phyllosphere microbes. We also highlight that soils may limit the spread of RDs-associated microbes and ARGs.

The Diversity of the Genus Tuber in Greece-A New Species to Science in the Maculatum Clade and Seven First National Records

Ectomycorrhizal fungi of the genus Tuber (Ascomycota) produce hypogeous ascomata commonly known as truffles. Despite their high ecological and economic importance, a considerable gap of knowledge exists concerning the diversity of Tuber species in the eastern Mediterranean region. In the frame of this study, more than 200 Tuber collections, originating from various regions of Greece, were examined. A new species to science, i.e., Tuber leptodermum, is formally described. Tuber leptodermum is grouped in the Maculatum clade, as revealed by the ITS and LSU rDNA concatenated phylogenetic tree, and appears as sister to T. foetidum. In addition, T. leptodermum exhibits distinct morphoanatomic features: it produces medium-sized, dark-brown ascomata with a thin pseudoparenchymatous peridium, composed of globose-to-angular cells and forms one-to-four-spored asci containing reticulate-alveolate, ellipsoid ascospores with broad meshes. Thirty other phylogenetic species are identified: seven of them (i.e., T. anniae, T. buendiae, T. conchae, T. dryophilum, T. monosporum, T. regianum and T. zambonelliae) constitute new records for the Greek mycobiota, while the presence of five other species is molecularly confirmed for the first time. Moreover, the existence of ten undescribed phylogenetic species is revealed, six of which are reported for the first time in Greece. Several taxonomic and phylogenetic issues and discrepancies in the genus Tuber are discussed in relation to the new findings.

Impacts of sulfur application on microbial communities and functional attributes in rubber plantation soil

Elemental sulfur is widely used in fungicide applications to control crop diseases in agricultural systems, but its effects on soil microbial communities are largely unknown. In China, significant amounts of elemental sulfur are sprayed annually on rubber plantations to support crop performance. To investigate the effects of sulfur spraying on microbial diversity, composition, interactions, and functionalities in rubber plantation soil, soil samples from rubber plantations in Yunnan, South China, were collected, and bacterial and fungal communities were analyzed through high-throughput sequencing. Results showed that sulfur application did not alter the alpha diversity but the beta diversity of the soil bacterial community. Notably, sulfur disturbed the relative abundances of Chloroflexi and Planctomycetes. Certain bacteria (e.g., Bacillus and Sinomonas) thrived under sulfur treatment, influencing nutrient cycling. The ecological network analysis revealed enhanced bacterial and fungal interconnections. Sulfur application had a limited impact on microbial phenotypes and community functions, yet it inhibited sulfur compound respiration. These findings indicate that sulfur spraying can shift microbial community composition and influence nutrient cycling by favoring specific microbial groups. Despite its limited impact on microbial phenotypes, sulfur affects key metabolic processes, such as sulfur respiration, which are vital for soil health and microbial activity. The results highlight the need for sustainable sulfur management to optimize nutrient cycling and soil health on rubber plantations.

A Long-Term Ecological Research Data Set From the Marine Genetic Monitoring Program ARMS-MBON 2018-2020

Molecular methods such as DNA/eDNA metabarcoding have emerged as useful tools to document the biodiversity of complex communities over large spatio-temporal scales. We established an international Marine Biodiversity Observation Network (ARMS-MBON) combining standardised sampling using autonomous reef monitoring structures (ARMS) with metabarcoding for genetic monitoring of marine hard-bottom benthic communities. Here, we present the data of our first sampling campaign comprising 56 ARMS units deployed in 2018-2019 and retrieved in 2018-2020 across 15 observatories along the coasts of Europe and adjacent regions. We describe the open-access data set (image, genetic and metadata) and explore the genetic data to show its potential for marine biodiversity monitoring and ecological research. Our analysis shows that ARMS recovered more than 60 eukaryotic phyla capturing diversity of up to ~5500 amplicon sequence variants and ~1800 operational taxonomic units, and up to ~250 and ~50 species per observatory using the cytochrome c oxidase subunit I (COI) and 18S rRNA marker genes, respectively. Further, ARMS detected threatened, vulnerable and non-indigenous species often targeted in biological monitoring. We show that while deployment duration does not drive diversity estimates, sampling effort and sequencing depth across observatories do. We recommend that ARMS should be deployed for at least 3-6 months during the main growth season to use resources as efficiently as possible and that post-sequencing curation is applied to enable statistical comparison of spatio-temporal entities. We suggest that ARMS should be used in biological monitoring programs and long-term ecological research and encourage the adoption of our ARMS-MBON protocols.

Urbanization leads to asynchronous homogenization of soil microbial communities across biomes

Soil bacterial and fungal communities play fundamental roles in biogeochemical cycles and ecosystem stability. Urbanization alters soil properties and microbial habitats, driving shifts in community composition, yet the divergent responses of bacteria and fungi and their ecological consequences remain inadequately understood. To elucidate these differential responses, we investigated soil bacterial and fungal communities along an urbanization gradient, ranging from undisturbed reference forests to urban parks, across three distinct climatic regions. To capture different disturbance intensities, urban parks were classified by tree age into old parks (>60-year-old trees) and young parks (10-20-year-old trees). Climate had a strong influence on soil microbiota, yet urbanization still significantly altered both bacterial and fungal communities in all regions. Urban disturbances homogenized soil microbial communities: average similarity among bacterial communities increased from ∼79 % in forests to ∼85 % in young urban parks, indicating substantial homogenization, whereas fungal communities showed little homogenization. Urbanization also homogenized microbial functional traits, with a greater reduction in trait dissimilarity for bacteria than for fungi. Bacterial communities exhibited high adjustability to urban conditions, dominated by generalist taxa (∼90 %), whereas fungal communities consisted mostly of specialists (∼83 %). Despite these asynchronous responses-bacteria adjusting and homogenizing more than fungi-overlapping functional traits between bacteria and fungi help maintain functional resilience in urban ecosystems.

Soil microbial legacies and drought mediate diversity-invasibility relationships in non-native communities

High native species diversity generally suppresses non-native invasions, but many ecosystems are now characterized by non-native assemblages that vary in species diversity. How this non-native species diversity affects subsequent invaders and its environmental dependence remain unclear. We conducted a plant-soil feedback experiment. In the conditioning phase, we created three diversity levels (1, 2, or 4 species) using six non-native species to condition the soil. In the responding phase, we planted these six species individually with soil inocula and exposed them to two watering treatments (well-watered vs drought). Under well-watered conditions, the non-native biomass increased with soil inocula generated by different non-native diversity. This biomass pattern was mainly related to arbuscular mycorrhizal fungal richness which increased with non-native species diversity. However, under drought conditions, the non-native biomass did not depend on soil inocula generated by non-native diversity. Our results reveal the crucial role of soil microbial legacies in driving the positive diversity-invasibility relationships of non-native communities and drought stress can eliminate these positive relationships. These findings provide an explanation for the commonly observed co-occurrence of multiple non-native species in nature, predicting an accelerating accumulation of non-native species in a benign environment, but not in a stressed environment.

From air to insight: the evolution of airborne DNA sequencing technologies

Historically, the analysis of airborne biological organisms relied on microscopy and culture-based techniques. However, technological advances such as PCR and next-generation sequencing now provide researchers with the ability to gather vast amounts of data on airborne environmental DNA (eDNA). Studies typically involve capturing airborne biological material, followed by nucleic acid extraction, library preparation, sequencing and taxonomic identification to characterize the eDNA at a given location. These methods have diverse applications, including pathogen detection in agriculture and human health, air quality monitoring, bioterrorism detection and biodiversity monitoring. A variety of methods are used for airborne eDNA analysis, as no single pipeline meets all needs. This review outlines current methods for sampling, extraction, sequencing and bioinformatic analysis, highlighting how different approaches can influence the resulting data and their suitability for specific use cases. It also explores current applications of airborne eDNA sampling and identifies research gaps in the field.

Biodiversity of the Bacterial and Fungal Microbiome and Associated Inflammatory Cytokine Profile in Chronic Rhinosinusitis

BACKGROUND

Dysbiosis of the bacterial and fungal microbiome has been increasingly implicated in the pathogenesis of chronic rhinosinusitis (CRS). This study explores the relationship between microbiome and mycobiome biodiversity and type 2 (T2) versus non-type 2 (NT2) inflammation.

METHODS

Mucosal tissues from the ethmoid sinus were collected during endoscopic sinus (CRS) and skull base (controls) surgery between January 2020 and July 2021. Specimens underwent 16S rRNA (bacterial) and internal transcribed spacer (fungal) gene sequencing, along with cytokine analysis using the Luminex assay. Based on cytokine (IL-4, IL-5, IL-13) concentrations and the presence of eosinophils, CRS cases were classified into T2 or NT2 inflammatory profiles. The relationships between CRS endotype and the biodiversity of the microbiome and mycobiome were assessed.

RESULTS

Specimens from 92 patients (30 control, 31 CRSwNP, 31 CRSsNP) were included in the analyses. Among 62 CRS cases, 20 exhibited T2 inflammation and 42 exhibited NT2 inflammation. Compared with control specimens, NT2 specimens exhibited significantly lower amplicon sequence variants (mean difference -149, 95% CI [-261, -37], p = 0.007), Shannon index (-0.48 [-0.79, -0.16], p = 0.002), and Simpson index (-0.003 [-0.005, -0.001], p = 0.002) for bacterial alpha diversity. However, no significant differences in bacterial alpha diversity were observed between T2 specimens and controls, or between T2 and NT2 specimens. Fungal biodiversity did not differ significantly across endotype and control groups.

CONCLUSION

Dysbiosis of the sinus bacterial microbiome is more strongly associated with a NT2-mediated inflammatory profile than with a T2-mediated inflammatory profile.

EukFunc: A Holistic Eukaryotic Functional Reference for Automated Profiling of Soil Eukaryotes

The soil eukaryome constitutes a significant portion of Earth's biodiversity that drives major ecosystem functions, such as controlling carbon fluxes and plant performance. Currently, however, we miss a standardised approach to functionally classify the soil eukaryome in a holistic way. Here we compiled EukFunc, the first functional reference database that characterises the most abundant and functionally important soil eukaryotic groups: fungi, nematodes and protists. We classified the 14,060 species in the database based on their mode of nutrient acquisition into the main functional classes of symbiotroph (40%), saprotroph (26%), phototroph (17%), predator (16%) and unknown (2%). EukFunc provides further detailed information about nutrition mode, including a secondary functional class (i.e., for organisms with multiple nutrition modes), and preyed or associated organisms for predatory or symbiotic taxa, respectively. EukFunc is available in multiple formats for user-friendly functional analyses of specific taxa or annotations of metabarcoding datasets, both embedded in the R package EukFunc. Using a soil dataset from alpine and subalpine meadows, we highlighted the extended ecological insights obtained from combining functional information across the entire soil eukaryome as compared to focusing on fungi, protists or nematodes individually. EukFunc streamlines the annotation process, enhances efficiency and accuracy, and facilitates the investigation of the functional roles of soil eukaryotes-a prerequisite to better understanding soil systems.

Plant development influences dynamic shifts in the root compartment microbiomes of wild and domesticated finger millet cultivars

BACKGROUND

Plant-microbe interactions in the rhizosphere and endosphere are crucial for maintaining plant health and ecosystem dynamics. These interactions are shaped by several factors, including the plant's developmental stage, domestication, and specific root compartments. Different plant cultivars influence unique microbial communities by secreting root exudates that either support beneficial symbionts or inhibit pathogens. This study examined the microbial community structures in the endosphere and rhizosphere of wild-type finger millet and five domesticated cultivars at two developmental stages.

RESULTS

Our results revealed that the plant developmental stage, root compartment, and domestication significantly influence the root-associated microbiomes. Interestingly, only about 8% of the core microbiota was consistently shared between the soil and plants, indicating that 92% shifted dynamically depending on plant type and developmental stage. Pseudomonadota, Actinomycedota, and Bacteroidota were the dominant bacterial phyla, while Ascomycota and Basidiomycota were the primary fungal phyla across all samples, displaying distinct abundance patterns. Notably, an increase in Actinomycedota in the endosphere correlated with a reduction in Pseudomonadota. The most significant shifts in microbial community composition occurred in the rhizosphere during the flowering stage, primarily driven by the genus Pseudomonas. These findings demonstrate that plant developmental stages and domestication influence the recruitment of specific microbial taxa to meet the plant's needs, particularly in various root compartments. This selective recruitment highlights the active role of plants in shaping their microbiomes, providing insights into the potential for manipulating these communities to enhance crop productivity sustainably.

CONCLUSION

Our results indicate that both the host developmental stage and domestication significantly influence the assembly and structure of the plant microbiome. Plant root compartments can selectively recruit specific taxa from associated core microbial communities to meet their needs, depending on the plant's developmental stage and the particular root compartment involved. These findings demonstrate that the deterministic selection pressures exerted by plants during their growth and development greatly affect their microbial communities. This has important implications for developing sustainable farming practices, reducing reliance on chemical fertilizers and pesticides, and enhancing future crop productivity.

Uncovering microbial interactions in a persistent Planktothrix bloom: Towards early biomarker identification in hypereutrophic lakes

Cyanobacterial harmful algal blooms pose significant threats to global water supplies, ecosystems, and economies. Among the harmful cyanobacteria, Planktothrix, a resilient and toxin-producing filamentous cyanobacterium, has garnered increasing attention. However, an understanding of the entire microbiome, particularly the phycosphere surrounding Planktothrix blooms, remains largely unexplored. To the best of our knowledge, this is the first comprehensive study combining 16S rDNA and fungal internal transcribed spacer amplicon sequencing and shotgun metagenomics to elucidate Planktothrix bloom microbiomes and identify potential microbial or functional biomarkers for CyanoHABs. Our observations revealed that a summer bloom in Grand Lake St. Marys was initiated with Dolichospermum and then shifted to Planktothrix dominance. This transition was associated with nitrogen metabolism genes, suggesting that nitrogen plays a key role in bloom persistence through interactions among nitrogen-fixing bacteria, ammonia-oxidizing archaea, anammox bacteria, and denitrifiers. Additionally, metagenomic data revealed a strong positive correlation of toxin concentration with carbohydrate-nitrogen-sulfur-fatty acid associated metabolic pathways and a strong negative correlation with pollutant degradation pathways. Intriguingly, diazotrophic methane-related microbes were detected, which opens discussion on potential symbiosis that couples nitrogen and carbon metabolism. Toxin-degrading bacteria, such as Polynucleobacter and Acidovorax, were positively correlated with fungi like Vishniacozyma, proposing their cooperative roles during bloom events. Notably, Rhodobacter, a photosynthetic purple non-sulfur bacterium, showed strong negative correlations with both Planktothrix and the toxin-producing gene mcyE, positioning it as a promising biomarker for early bloom detection. Overall, this study advances the understanding of Planktothrix-dominated bloom ecology and highlights microbial signatures for proactive CyanoHAB management in freshwater systems.

Sampling eDNA at outflows from artificial drainage systems: what is the potential to monitor landscape degradation?

Wetlands have been drained extensively for productive land use, transforming the biodiversity of whole landscapes. Such transformation primarily affects the huge biodiversity across the terrestrial and aquatic environments that is difficult to observe directly, especially in the case of microorganisms. We explored whether environmental DNA (eDNA) from the flowing water could serve as a data source for characterizing the level of biological degradation of drained and managed forest-wetland landscapes. We took spatially and seasonally replicated samples from nine hydrologically monitored outflows at small drained catchments in Estonia in order to understand the variation in their eDNA-based diversity. Using PacBio long-read sequencing, we detected a large taxonomic diversity of eukaryotes (approx. 6000 operational taxonomic units (OTUs)), which was spatially and seasonally structured, but also highly variable within individual ditches. Even in fungi (the best-represented taxon group), the OTU accumulation curves did not level off despite high volumes of filtered water; however, many interesting species records were obtained (particularly on pathogenic microorganisms). We conclude that eDNA can provide valuable insights into the biodiversity of hydrologically drained areas, but our results indicate high heterogeneity among samples (apparently due to both actual assemblage differences and sampling errors) as a major problem for standard environmental assessment. Combining eDNA methods with other ecological assessment techniques is a priority for further research in these systems.

Conventional and organic farms with more intensive management have lower soil functionality

Organic farming is often considered to be more sustainable than conventional farming. However, both farming systems comprise highly variable management practices. In this study, we show that in organic and conventional arable fields, the multifunctionality of soils decreases with increasing agricultural management intensity. Soil organic carbon content and bacterial biomass, respectively, were the strongest abiotic and biotic predictors of soil multifunctionality. Greater soil multifunctionality was associated with less-frequent inversion tillage and higher frequency of grass-legume cover cropping, and organic farming did not outperform conventional farming. Our results suggest that reducing management intensity will enhance soil multifunctionality in both conventional and organic farming. This implies that, in contexts where high-yielding, high-intensity agriculture prevails, the paradigm of sustainable intensification should be replaced by "productive deintensification."

Gut Mycobiome: Latest Findings and Current Knowledge Regarding Its Significance in Human Health and Disease

The gut mycobiome, the fungal component of the gut microbiota, plays a crucial role in health and disease. Although fungi represent a small fraction of the gut ecosystem, they influence immune responses, gut homeostasis, and disease progression. The mycobiome's composition varies with age, diet, and host factors, and its imbalance has been linked to conditions such as inflammatory bowel disease (IBD) and metabolic disorders. Advances in sequencing have expanded our understanding of gut fungi, but challenges remain due to methodological limitations and high variability between individuals. Emerging therapeutic strategies, including antifungals, probiotics, fecal microbiota transplantation, and dietary interventions, show promise but require further study. This review highlights recent discoveries on the gut mycobiome, its interactions with bacteria, its role in disease, and potential clinical applications. A deeper understanding of fungal contributions to gut health will help develop targeted microbiome-based therapies.

Distribution patterns of fungal community diversity in the dominant tree species Dacrydium pectinatum and Vatica mangachapoi in tropical rainforests

Plant microbial communities are shaped by plant compartments, but the patterns of fungal communities in aboveground and belowground compartments, and which environmental factors can affect them, remain unknown. Here, to address this research gap, high-throughput sequencing technology was performed to investigate the diversity of fungal communities in leaves' and roots' compartments of Dacrydium pectinatum and Vatica mangachapoi from Hainan Island of China. Fungal communities in leaves and roots exhibited significant differences. Eurotiomycetes (16.57%) and Dothideomycetes (45.57%) were predominantly found in leaves, while Agaricomycetes (36.53%) dominated in roots. Compared to the roots, the leaf compartments had higher α-diversity. According to the Mantel test, soil pH mainly influenced roots, while the main driving factors for leaves were rainfall and temperature. The proportion of dispersal-limited processes in rhizoplane (76.67%) and root endosphere (73.81%) were greater than that in leaf epiphytic (62.38%) and leaf endophytic (68.1%), driven by ectomycorrhizal fungi with known dispersal limitations. In summary, the compositions of the leaf and root fungal communities of both endangered tree species differed, partly driven by environmental factors unique to each compartment. Our results provide valuable theoretical and practical insights for preserving tropical tree species.

IMPORTANCE

Understanding the assembly of microbial communities across different compartments is a prerequisite for harnessing them to enhance plant growth. Our findings reveal significant differences in fungal community structures between the root and leaf compartments. Compared to the roots, the leaf compartments exhibited higher α-diversity. While soil pH mainly influenced fungal communities in the roots, the primary drivers for the leaves were rainfall and temperature. The dispersal-limited processes of fungal communities in the roots were greater than those in the leaves, primarily influenced by mycorrhizal fungi. These findings demonstrate compartment-specific plant-microbe interactions and environmental responses, offering actionable insights for conserving tropical tree species through habitat optimization (e.g., soil pH management) and dispersal corridor preservation. This compartment-aware perspective enhances our ability to leverage microbial functions to improve the resilience of endangered trees in the face of climate change.

Deposited dead algae influence the microbial communities and functional potentials on the surface sediment in eutrophic shallow lakes

Dead algae deposition will change the nutrient transformation on the sediment-water interface. However, the key factors that drive nutrient turnover, particularly the influence of sediment microbiota, remain poorly understood. As a result, this study conducted an 80-day simulated incubation to investigate the effect of different deposition of death algae on microbial communities and functional potentials in sediments. It was revealed that dead algae deposition changed the microbial communities and interactions. Changes in the bacteria are not only reflected in community composition and diversity but also in the interrelation among bacteria taxa, while changes in the fungi are mainly reflected in the interrelation among fungi taxa. Meanwhile, dead algae deposition increased the abundance of mostly functional genes related to the C, N, P, and S cycle processes and improved the function potentials of microorganisms. Both of them led to the increase of PO43-, NO3-, NH4+, and TOC content in the overlying water, influencing the nutrient cycle processes. Moreover, partial least squares path modeling indicated which key factors are to influence different nutrient cycle processes. Sediment nutrients directly influenced the P cycle process, whereas the C, N, and S cycle processes were directly affected by the changes in biological properties. These results provide a new perspective on the effects of dead algal deposition on the sediment nutrient cycle processes mediated by the sediment microbiota.

High mycorrhizal specificity in the monotypic mycoheterotrophic genus Relictithismia (Thismiaceae)

Mycoheterotrophic plants, which depend entirely on mycorrhizal fungi for carbon acquisition, often exhibit high specificity toward their fungal partners. Members of Thismiaceae are generally recognized for their extreme mycorrhizal specialization and rarity. In this study, we examined the mycorrhizal associations of Relictithismia, a recently discovered monotypic genus within Thismiaceae, and Thismia abei, a Thismia species with a similar distribution in southern Japan, by employing high-throughput DNA sequencing of the 18S rRNA gene. Our analyses revealed that both R. kimotsukiensis and T. abei are predominantly associated with two specific virtual taxa (VTX00295 and VTX00106) of the genus Rhizophagus (Glomeraceae). These shared associations may reflect either phylogenetic niche conservatism, in which the common ancestor of R. kimotsukiensis and T. abei retained the same AM fungal partners, or convergent evolution, in which the AM fungal phylotypes were independently recruited due to their potential benefits for these mycoheterotrophic plants. Furthermore, BLAST searches demonstrated that VTX00295 and VTX00106 are widely distributed globally, suggesting that highly specialized mycorrhizal interactions are unlikely to be the primary drivers of the limited distribution and rarity of R. kimotsukiensis and T. abei. Overall, our findings enhance our understanding of high mycorrhizal specificity in Thismiaceae. However, broader investigations, combining extensive sampling of Thismiaceae species with ancestral state reconstruction, are needed to determine whether the shared associations detected here reflect phylogenetic niche conservatism or convergent evolution.

Teosinte-derived SynCom and precision biofertilization modulate the maize microbiome, enhancing growth, yield, and soil functionality in a Mexican field

Modern agriculture faces the challenge of optimizing fertilization practices while maintaining soil resilience and microbial diversity, both critical for sustainable crop production. We evaluated the effects of multiple fertilization strategies on soil microbial communities and plant performance, comparing conventional methods (urea-based and phosphorus fertilizers applied manually or via drone-assisted precision delivery) with biofertilization using a synthetic microbial consortium (SynCom) derived from teosinte-associated microbes. This SynCom consisted of seven bacterial strains: Serratia nematodiphila EDR2, Klebsiella variicola EChLG19, Bacillus thuringiensis EML22, Pantoea agglomerans EMH25, Bacillus thuringiensis EBG39, Serratia marcescens EPLG52, and Bacillus tropicus EPP72. High-throughput sequencing revealed significant shifts in bacterial and fungal communities across treatments. Untreated soils showed limited diversity, dominated by Enterobacteriaceae (>70%). Conventional fertilization gradually reduced Enterobacteriaceae while increasing Pseudomonas and Lysinibacillus populations. Drone-assisted conventional fertilization notably enhanced Acinetobacter and Rhizobiales growth. Biofertilization treatments produced the most pronounced shifts, reducing Enterobacteriaceae below 50% while significantly increasing beneficial taxa like Bacillus, Pantoea, and Serratia. Network analysis demonstrated that microbial interaction complexity increased across treatments, with Bacillus emerging as a keystone species. Drone-assisted biofertilization fostered particularly intricate microbial networks, enhancing synergistic relationships involved in nutrient cycling and biocontrol, though maintaining the stability of these complex interactions requires careful monitoring. Our findings provide key insights into how precision biofertilization with teosinte-derived microbial consortia can sustainably reshape the maize microbiome, improving crop performance and soil resilience.

Maize associated bacterial and fungal microbiomes show contrasting conformation patterns dependent on plant compartment and water availability

Plant-associated microorganisms can help crops to alleviate stress and increase the resilience of agricultural ecosystems to climate change. However, we still lack knowledge on the dynamics of soil and plant microbiomes and their response to changing conditions. This information is essential for the development of microbiome-based solutions to improve crop resilience to stressors associated with climate change. In this work, we explored: (i) the conformation of the bacterial and fungal assemblages of different soil and plant compartments (bulk soil, rhizosphere, roots, leaves and grains) along the crop cycle of maize in an open field trial; and (ii) the effect of water restriction on the maize microbiome, comparing optimal irrigation with a 30% reduction of water supply. Our results show a dynamic compartment-driven recruitment of microorganisms with contrasting patterns for bacteria and fungi that were intensified towards the end of the plant cycle. Roots showed the most differentiated bacterial assemblage while fungi conformed a very distinct community in the leaves, suggesting a relevant contribution of aerial fungal propagules to the microbiome of this plant organ. Regarding the grain, bacterial communities looked closer to those in the leaves, while fungal communities were more like those in the root. Despite the reductions in plant growth and yield, the microbiome of limited-watered plants did not show severe alterations. Still, significant impacts were observed within compartments, being fungi more responsive to limited watering than bacteria, with hallmark fungal ASVs for each compartment and irrigation regime. Network analysis suggests that bacteria and fungi may play different roles in the shifts observed under water limitation. Our study highlights the importance of conducting multikingdom analyses for a holistic understanding of the dynamics and evolution of the microbial assemblages in the whole plant and their roles in plant response to environmental stressors.

Divergent altitudinal patterns of arbuscular and ectomycorrhizal fungal communities in a mid-subtropical mountain ecosystem

Arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) form ubiquitous symbiotic relationships with plants through co-evolutionary processes, providing multiple benefits for plant growth, productivity, health, and stress mitigation. Mountain ecosystem multifunctionality is significantly influenced by mycorrhizal responses to climate change, highlighting the importance of understanding the complex interactions between these fungi and environmental variables. In this study, we investigated five vegetation zones across an altitudinal gradient (675-2157 m a.s.l.) in Wuyi Mountain, one of the most well-preserved mid-subtropical mountain ecosystems in eastern China. Using high-throughput sequencing, we examined the altitudinal distribution patterns, community assembly mechanisms, and network interactions of soil AMF and EMF. Our analyses demonstrated significant altitudinal variations in the composition and diversity of mycorrhizal fungal communities. AMF richness peaked in the subalpine dwarf forest at intermediate elevations, whereas EMF richness was highest in the low-altitude evergreen broad-leaved forest, showing a marked decrease in the alpine meadow ecosystem. β-diversity decomposition revealed that species turnover constituted the primary mechanism of community differentiation for both fungal types, explaining >56% of the observed variation. Stochastic processes dominated community assembly, with the relative importance of dispersal limitation and drift showing distinct altitudinal patterns. Network analysis indicated that AMF networks reached maximum complexity in evergreen broad-leaved forests, while EMF networks showed similar complexity levels in coniferous forests. Among the examined factors, soil properties emerged as the predominant driver of altitudinal variations in ecosystem multifunctionality, followed by AMF communities and climatic variables. These findings provide critical insights into the ecological functions and environmental adaptations of mycorrhizal fungi, advancing our understanding of their responses to environmental changes in mountain ecosystems and informing evidence-based conservation strategies.

Efficiency of the Coriolis µ Air Sampling Device for Fungal Contamination Analysis of Indoor Air: A Case Study

Molds are frequent indoor contaminants, where they can colonize many materials. The subsequent aerosolization of fungal spores from moldy surfaces can strongly impact indoor air quality and the health of occupants. The investigation of fungal contamination of habitations is a key point in evaluating sanitary risks and understanding the relationship that may exist between the fungal presence on surfaces and air contamination. However, to date there is no "gold standard" of sampling indoor air for such investigations. Among various air sampling methods, impingement can be used for capturing fungal spores, as it enables real-time sampling and preserves analytical follow-up. Its efficiency varies depending on several factors, such as spore hydrophobicity, sampling conditions, etc. Sampling devices may also impact the results, with recovery rates sometimes lower than filtration-based methods. The Coriolis µ air sampler, an impingement-based device, utilizes centrifugal force to concentrate airborne particles into a liquid medium, offering flexibility for molecular analysis. Several studies have used this device for air sampling, demonstrating its application in detecting pollen, fungal spores, bacteria, and viruses, but it is most often used in laboratory conditions. The present case study, conducted in a moldy house, aims to investigate the efficiency of this device in sampling fungal spores for DNA analysis in indoor environments. The results obtained suggest that the use of this device requires an optimized methodology to enhance its efficiency and reliability in bioaerosol research.

Exploring the microorganisms biodiversity associated with sponge species in the red sea through 18S ribosomal RNA gene sequencing

Around the world, sponges play a significant role in marine ecosystems, and a wide variety of sponge species can be found in the coast of Red Sea of Saudi Arabia. The unique environmental conditions of the Red Sea, including warm, oligotrophic water and high salinity, have encouraged the growth of abundant sponge fauna. Our study aims to investigate the biodiversity, taxonomic composition, and phylogenetic relationships of eukaryotic organisms linked with sponges in the Red Sea off the coast of Saudi Arabia and infer the possible ecological roles and functional contributions of the identified eukaryotic taxa to sponge health and ecosystem functioning. The study investigated the microbial diversity, focusing on the genera Hyalosynedra sp., Navicula sp., Papiliocellulus sp., Psammodictyon sp., Pynococcus sp., Ostreococcus sp., Micromonas sp., and other unclassified species. Our metagenomic analysis and phylogenetic evaluation revealed a deep and diverse microbial community, with each genus performing significant ecological roles, including nutrient cycling, primary production, and contributing to marine food networks. Moreover, these genera display promising biotechnological prospects, including uses in bioremediation, biofuel production, and the synthesis of high-value biomolecules. Comparative analysis with other marine regions has focused on both the similarities and unique aspects of the Red Sea microbial community, which are influenced by its distinct environmental conditions. The gained findings contribute to a deeper understanding of the ecological dynamics in the Red Sea and open new avenues for biotechnological exploration in marine ecosystems.

Soil and litter microbiomes as joint drivers of ecosystem multifunctionality in a 60-year-old forest plantation

Afforestation is considered an effective strategy to mitigate a changing climate. However, it remains unclear how ecosystem multifunctionality (EMF) changes under long-term afforestation and the role of soil and litter microbiomes in this process. To address this, we studied a well-characterised 60-year-old plantation and analysed soil and litter microbial communities influencing EMF variations. We found that long-term plantations significantly enhance forest EMF, largely due to the joint contributions of soil and litter microbial communities. In older stands (60 years), the stability of microbial interaction networks increased, while the α (Shannon) diversity of soil bacteria and litter fungi significantly decreased during succession. This transition suggests that microbial communities shifted towards more stable interactions rather than increased diversity, a strategic adaptation that potentially allows microbes to effectively utilize the continuously increasing resource supply, ultimately enhancing forest EMF. Structural equation modelling revealed that biotic factors, including composition of soil and litter microbial communities and their network stability, coupled with abiotic factors such as soil and litter physicochemical properties, jointly explained 98 % of EMF variation. This study highlighted the role of both soil and litter microbes in enhancing EMF in long-term plantation forests, offering new insights into the ecosystem service functions of plantations.

FunVIP: Fungal Validation and Identification Pipeline based on phylogenetic analysis

The increase of sequence data in public nucleotide databases has made DNA sequence-based identification an indispensable tool for fungal identification. However, the large proportion of mislabeled sequence data in public databases leads to frequent misidentifications. Inaccurate identification is causing severe problems, especially for industrial and clinical fungi, and edible mushrooms. Existing species identification pipelines require separate validation of a dataset obtained from public databases containing mislabeled taxonomic identifications. To address this issue, we developed FunVIP, a fully automated phylogeny-based fungal validation and identification pipeline (https://github.com/Changwanseo/FunVIP). FunVIP employs phylogeny-based identification with validation, where the result is achievable only with a query, database, and a single command. FunVIP command comprises nine steps within a workflow: input management, sequence-set organization, alignment, trimming, concatenation, model selection, tree inference, tree interpretation, and report generation. Users may acquire identification results, phylogenetic tree evidence, and reports of conflicts and issues detected in multiple checkpoints during the analysis. The conflicting sample validation performance of FunVIP was demonstrated by re-iterating the manual revision of a fungal genus with a database with mislabeled sequences, Fuscoporia. We also compared the identification performance of FunVIP with BLAST and q2-feature-classifier with two mass double-revised fungal datasets, Sanghuangporus and Aspergillus section Terrei. Therefore, with its automatic validation ability and high identification performance, FunVIP proves to be a highly promising tool for achieving easy and accurate fungal identification.

Teknonaturalist: A Snakemake Pipeline for Assessing Fungal Diversity From Plant Genome Bycatch

Relatively little is known of the host associations and compatibility of fungal plant pathogens and endophytes. Publicly available plant genomic DNA can be mined to detect incidental fungal DNA, but taxonomic assignment can be challenging due to short lengths and variable discriminative power among different genomic regions and taxa. Here, we introduce a computationally lightweight and accessible Snakemake pipeline for rapid detection and classification (identification and assignment to taxonomic rank) of pathogenic and endophytic fungi (and other fungi associated with plants) that targets the internal transcribed spacer (ITS) region, a fungal barcode standard. We include methods for maximising query sequence length, which gives higher support for ITS1 and ITS2 taxonomic classifications by extending to other fragments of the ITS region and providing taxon-specific local cut-off and confidence scores. We demonstrate our pipeline with a case study using public genomic sequence data for six diverse plant species, including four species within Betula, an ecologically and economically important broadleaved forest tree genus, a shrub and a grass. Our pipeline classified fungi within minutes to a few hours per host individual, with 204 different fungal genera identified at high confidence (≥ 70%). Our pipeline detected and classified pathogenic and endophytic genera known to associate with Betula, and many others with no prior record of association. Our pipeline, leveraging existing sequence data, has several potential applications, including detecting cryptic fungal pathogens and helping characterise the endophytic fungal microbiome, bioprospecting commercially useful fungal species, and determining the plant host range of fungi.

Picky eaters: Selective microbial diet of avian ectosymbionts

Individual organisms can function as ecosystems inhabited by symbionts. Symbionts may interact with each other in ways that subsequently influence their hosts positively or negatively, although the details of how these interactions operate collectively are usually not well understood. Vane-dwelling feather mites are common ectosymbionts of birds and are proposed to confer benefits to hosts by consuming feather-degrading microbes. However, it is unknown whether these mites exhibit generalist or selective diets, or how their dietary selection could potentially impact their symbiotic functional nature. In this study, we conducted 16S rDNA and ITS1 amplicon sequencing to examine the microbial diet of feather mites. We characterized and compared the diversity and composition of bacteria and fungi in the bodies of mites living on feathers of the Prothonotary Warbler, Protonotaria citrea, to microbial assemblages present on the same feathers. We found less diverse, more compositionally similar microbial assemblages within mites than on feathers. We also found that mites were resource-selective. Based on the identity and known functions of microbes found within and presumably preferred by mites, our results suggest that these mites selectively consume feather-degrading microbes. Therefore, our results support the proposition that mites confer benefits to their hosts. This study provides insight into symbioses operating at multiple biological levels, highlights the ecological and evolutionary importance of the synergistic interactions between species, and greatly expands our understanding of feather mite biology.