Transcriptomic analyses of bacterial growth on fungal necromass reveal different microbial community niches during degradation.

Bacteria are major drivers of organic matter decomposition and play crucial roles in global nutrient cycling. Although the degradation of dead fungal biomass (necromass) is increasingly recognized as an important contributor to soil carbon (C) and nitrogen (N) cycling, the genes and metabolic pathways involved in necromass degradation are less characterized. In particular, how bacteria degrade necromass containing different quantities of melanin, which largely control rates of necromass decomposition , is largely unknown.

Fungi rather than bacteria drive early mass loss from fungal necromass regardless of particle size.

Microbial necromass is increasingly recognized as an important fast-cycling component of the long-term carbon present in soils. To better understand how fungi and bacteria individually contribute to the decomposition of fungal necromass, three particle sizes (>500, 250-500, and <250 μm) of Hyaloscypha bicolor necromass were incubated in laboratory microcosms inoculated with individual strains of two fungi and two bacteria. Decomposition was assessed after 15 and 28 days via necromass loss, microbial respiration, and changes in necromass pH, water content, and chemistry.

Mast seeding in European beech (Fagus sylvatica L.) is associated with reduced fungal sporocarp production and community diversity.

Mast seeding is a well-documented phenomenon across diverse forest ecosystems. While its effect on aboveground food webs has been thoroughly studied, how it impacts the soil fungi that drive soil carbon and nutrient cycling has not yet been explored. To evaluate the relationship between mast seeding and fungal resource availability, we paired a Swiss 29-year fungal sporocarp census with contemporaneous seed production for European beech (Fagus sylvatica L.

Primer pairs, PCR conditions, and peptide nucleic acid clamps affect fungal diversity assessment from plant root tissues.

High-throughput sequencing has become a prominent tool to assess plant-associated microbial diversity. Still, some technical challenges remain in characterising these communities, notably due to plant and fungal DNA co-amplification. Fungal-specific primers, Peptide Nucleic Acid (PNA) clamps, or adjusting PCR conditions are approaches to limit plant DNA contamination.

Suillus: an emerging model for the study of ectomycorrhizal ecology and evolution.

Research on mycorrhizal symbiosis has been slowed by a lack of established study systems. To address this challenge, we have been developing Suillus, a widespread ecologically and economically relevant fungal genus primarily associated with the plant family Pinaceae, into a model system for studying ectomycorrhizal (ECM) associations. Over the last decade, we have compiled extensive genomic resources, culture libraries, a phenotype database, and protocols for manipulating Suillus fungi with and without their tree partners.

Herbarium specimens reveal that mycorrhizal type does not mediate declining temperate tree nitrogen status over a century of environmental change.

Rising atmospheric carbon dioxide concentrations (CO) and atmospheric nitrogen (N) deposition have contrasting effects on ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) symbioses, potentially mediating forest responses to environmental change. In this study, we evaluated the cumulative effects of historical environmental change on N concentrations and δN values in AM plants, EM plants, EM fungi, and saprotrophic fungi using herbarium specimens collected in Minnesota, USA from 1871 to 2016. To better understand mycorrhizal mediation of foliar δN, we also analyzed a subset of previously published foliar δN values from across the United States to parse the effects of N deposition and CO rise.

Defining a core microbial necrobiome associated with decomposing fungal necromass.

Despite growing interest in fungal necromass decomposition due to its importance in soil carbon retention, whether a consistent group of microorganisms is associated with decomposing necromass remains unresolved. Here, we synthesize knowledge on the composition of the bacterial and fungal communities present on decomposing fungal necromass from a variety of fungal species, geographic locations, habitats, and incubation times. We found that there is a core group of both bacterial and fungal genera (i.

Climate change-induced stress disrupts ectomycorrhizal interaction networks at the boreal-temperate ecotone.

The interaction networks formed by ectomycorrhizal fungi (EMF) and their tree hosts, which are important to both forest recruitment and ecosystem carbon and nutrient retention, may be particularly susceptible to climate change at the boreal-temperate forest ecotone where environmental conditions are changing rapidly. Here, we quantified the compositional and functional trait responses of EMF communities and their interaction networks with two boreal ( and ) and two temperate ( and ) hosts to a factorial combination of experimentally elevated temperatures and reduced rainfall in a long-term open-air field experiment. The study was conducted at the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment in Minnesota, USA, where infrared lamps and buried heating cables elevate temperatures (ambient, +3.

Fungal necromass presents a high potential for Mercury immobilization in soil.

Past industrial activities have generated many contaminated lands from which Mercury (Hg) escapes, primarily by volatilization. Current phytomanagement techniques aim to limit Hg dispersion by increasing its stabilization in soil. Although soil fungi represent a source of Hg emission associated with biovolatilization mechanisms, there is limited knowledge about how dead fungal residues (i.

Knowns and unknowns of the soil fungal necrobiome.

Dead microbial cells, commonly referred to as necromass, are increasingly recognized as an important source of both persistent carbon as well as nutrient availability in soils. Studies of the microbial communities associated with decomposing fungal necromass have accumulated rapidly in recent years across a range of different terrestrial ecosystems. Here we identify the primary ecological patterns regarding the structure and dynamics of the fungal necrobiome as well as highlight new research frontiers that will likely be key to gaining a full understanding of fungal necrobiome composition and its associated role in soil biogeochemical cycling.

Best practices in metabarcoding of fungi: From experimental design to results.

The development of high-throughput sequencing (HTS) technologies has greatly improved our capacity to identify fungi and unveil their ecological roles across a variety of ecosystems. Here we provide an overview of current best practices in metabarcoding analysis of fungal communities, from experimental design through molecular and computational analyses. By reanalysing published data sets, we demonstrate that operational taxonomic units (OTUs) outperform amplified sequence variants (ASVs) in recovering fungal diversity, a finding that is particularly evident for long markers.

An appraisal of antigen identification and IgG effector functions driving host immune responses in multiple sclerosis.

Increased immunoglobulin G (IgG) antibodies and oligoclonal bands (OCB) are the most characteristic features of multiple sclerosis (MS), a neuroinflammatory demyelinating disease with neurodegeneration at chronic stages. OCB are shown to be associated with disease activity and brain atrophy. Despite intensive research over the last several decades, the antigen specificities of the IgG in MS have remained elusive.

Warming drives a 'hummockification' of microbial communities associated with decomposing mycorrhizal fungal necromass in peatlands.

Dead fungal mycelium (necromass) represents a critical component of soil carbon (C) and nutrient cycles. Assessing how the microbial communities associated with decomposing fungal necromass change as global temperatures rise will help in determining how these belowground organic matter inputs contribute to ecosystem responses. In this study, we characterized the structure of bacterial and fungal communities associated with multiple types of decaying mycorrhizal fungal necromass incubated within mesh bags across a 9°C whole ecosystem temperature enhancement in a boreal peatland.

The slippery nature of ectomycorrhizal host specificity: fungi associated with novel pinoid () and abietoid () hosts.

is among the best-known examples of an ectomycorrhizal (ECM) fungal genus that demonstrates a high degree of host specificity. Currently recognized host genera of include , and , which all belong to the pinoid clade of the family Pinaceae. Intriguingly, sporocarps have been sporadically collected in forests in which known hosts from these genera are locally absent.

Nitrogen and phosphorus fertilization consistently favor pathogenic over mutualistic fungi in grassland soils.

Ecosystems across the globe receive elevated inputs of nutrients, but the consequences of this for soil fungal guilds that mediate key ecosystem functions remain unclear. We find that nitrogen and phosphorus addition to 25 grasslands distributed across four continents promotes the relative abundance of fungal pathogens, suppresses mutualists, but does not affect saprotrophs. Structural equation models suggest that responses are often indirect and primarily mediated by nutrient-induced shifts in plant communities.

Root presence modifies the long-term decomposition dynamics of fungal necromass and the associated microbial communities in a boreal forest.

Recent studies have highlighted that dead fungal mycelium represents an important fraction of soil carbon (C) and nitrogen (N) inputs and stocks. Consequently, identifying the microbial communities and the ecological factors that govern the decomposition of fungal necromass will provide critical insight into how fungal organic matter (OM) affects forest soil C and nutrient cycles. Here, we examined the microbial communities colonising fungal necromass during a multiyear decomposition experiment in a boreal forest, which included incubation bags with different mesh sizes to manipulate both plant root and microbial decomposer group access.

Comparative genomics reveals dynamic genome evolution in host specialist ectomycorrhizal fungi.

While there has been significant progress characterizing the 'symbiotic toolkit' of ectomycorrhizal (ECM) fungi, how host specificity may be encoded into ECM fungal genomes remains poorly understood. We conducted a comparative genomic analysis of ECM fungal host specialists and generalists, focusing on the specialist genus Suillus. Global analyses of genome dynamics across 46 species were assessed, along with targeted analyses of three classes of molecules previously identified as important determinants of host specificity: small secreted proteins (SSPs), secondary metabolites (SMs) and G-protein coupled receptors (GPCRs).

Does fungal competitive ability explain host specificity or rarity in ectomycorrhizal symbioses?

Two common ecological assumptions are that host generalist and rare species are poorer competitors relative to host specialist and more abundant counterparts. While these assumptions have received considerable study in both plant and animals, how they apply to ectomycorrhizal fungi remains largely unknown. To investigate how interspecific competition may influence the anomalous host associations of the rare ectomycorrhizal generalist fungus, Suillus subaureus, we conducted a seedling bioassay.

Antibodies from Multiple Sclerosis Brain Identified Epstein-Barr Virus Nuclear Antigen 1 & 2 Epitopes which Are Recognized by Oligoclonal Bands.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), the etiology of which is poorly understood. The most common laboratory abnormality associated with MS is increased intrathecal immunoglobulin G (IgG) synthesis and the presence of oligoclonal bands (OCBs) in the brain and cerebrospinal fluid (CSF). However, the major antigenic targets of these antibody responses are unknown.