Soil Fungi Research Articles

Imidacloprid Uptake and Accumulation in Lettuce Plant (Lactuca sativa L. var. longipolia) and Its Effects on Abundance of Microbial Communities in Cultivated and Non-Cultivated Arid Soil.

Systemic plant protection products, such as neonicotinoids (NIs), are capable of being translocated throughout a plant. Although NIs are less toxic to mammals, fish, and birds, their impact on microbial and non-target insects is of concern. This study investigates the uptake, translocation, and accumulation of the NI, imidacloprid (IMI), in romaine lettuce (Lactuca sativa L. var. longipolia). Exposing 15-day-old seedlings to "10 mg/L" of IMI, the effects on microbial communities in both cultivated (CS) and non-cultivated soil (NCS) were studied along with IMI translocation within plant tissues. The concentrations of IMI in soil varied temporally and between soil types after initial application, with a decrease from 2.0 and 7.7 mg/kg on the first day of sampling to 0.5 and 2.6 mg/kg on the final sampling day (day 35) for CS and NCS, respectively. The half-life of IMI soil was 10.7 and 72.5 days in CS and NCS, respectively, indicating that IMI degraded more quickly in CS, possibly due to smaller grain size, aeration, microbial degradation, and water flow. The accumulated concentrations of IMI in lettuce tissues ranged from 12.4 ± 0.2 and 18.7± 0.9 mg/kg in CS and NCS, respectively. The highest concentration of IMI was found in the shoots, followed by the roots, whereas the soil showed the lowest IMI residuals at the end of the trial. Soil bacteria and fungi were altered by the application of IMI, with a lower abundance index within the bacterial community, indicating a negative impact on the distribution of bacteria in the soil.

Earthworms alleviate microplastics stress on soil microbial and protist communities

Microplastic (MP) pollution can exert significant pressure on soil ecosystems, however, the interactive effects of MPs on soil bacterial, fungal and protist communities remains poorly understood. Soil macrofauna, such as earthworms, can be directly affected by MPs, potentially leading to a range of feedbacks on the soil microbial community. To address this, we conducted a microcosm experiment to examine the effects of conventional (i.e., polyethylene, polystyrene) and biodegradable MPs (i.e. PBAT, polylactic acid) on the structure of the soil bacterial, fungal, and protist communities in the presence or absence of earthworms. We found that MP contamination negatively affected the diversity and composition of soil microbial and protist communities, with smaller-sized conventional MPs having the most pronounced effects. For example, compared with the unamended control, small-sized polyethylene MPs both significantly reduced the Shannon diversity of soil bacteria, fungi, and protist by 4.3 %, 37.0 %, and 9.1 %, respectively. Biodegradable MPs increased negative correlations among bacteria, fungi, and protists. However, earthworms mitigated these effects, enhancing the diversity and altering the composition of these communities. They also increased the niche width and stability of the soil microbial food web network. Our study indicated that earthworms help attenuate the response of soil microorganisms to MPs stress by influencing the diversity and composition of soil microorganisms and soil physicochemical properties and underscores the importance of considering macrofauna in MPs research.

Response of soil fungi to textile dye contamination

This study examines the impact of textile dye contamination on the structure of soil fungal communities near a Shaoxing textile dye factory. We quantified the concentrations of various textile dyes, including anthraquinone azodye and phthalocyanine, which ranged from 20.20 to 140.62 mg kg^-1, 102.01–698.12 mg kg^-1, and 7.78–42.65 mg kg^-1, respectively, within a 1000 m radius of the factory. Our findings indicate that as dye concentration increases, the biodiversity of soil fungi, as measured by the Chao1 index, decreases significantly, highlighting the profound influence of dye contamination on fungal community structure. Additionally, microbial correlation network analysis revealed a reduction in fungal interactions correlating with increased dye concentrations. We also observed that textile dyes suppressed carbon and nitrogen metabolism in fungi while elevating the transcription levels of antioxidant-related genes. Enzymes such as lignin peroxidase (LiP), manganese peroxidase (MnP), laccase (Lac), dye-decolorizing peroxidases (DyPs), and versatile peroxidase (VP) were upregulated in contaminated soils, underscoring the critical role of fungi in dye degradation. These insights contribute to the foundational knowledge required for developing in situ bioremediation technologies for contaminated farmlands.

Differential responses of soil bacteria, fungi and protists to root exudates and temperature

The impact of climate warming on soil microbes has been well documented, with studies revealing its effects on diversity, community structure and network dynamics. However, the consistency of soil microbial community assembly, particularly in response to diverse plant root exudates under varying temperature conditions, remains an unresolved issue. To address this issue, we employed a growth chamber to integrate temperature and root exudates in a controlled experiment to examine the response of soil bacteria, fungi, and protists. Our findings revealed that temperature independently regulated microbial diversity, with distinct patterns observed among bacteria, fungi, and protists. Both root exudates and temperature significantly influenced microbial community composition, yet interpretations of these factors varied among prokaryotes and eukaryotes. In addition to phototrophic bacteria and protists, as well as protistan consumers, root exudates determined to varying degrees the enrichment of other microbial functional guilds at specific temperatures. The effects of temperature and root exudates on microbial co-occurrence patterns were interdependent; root exudates primarily simplified the network at low and high temperatures, while responses to temperature varied between single and mixed exudate treatments. Moreover, temperature altered the composition of keystone species within the microbial network, while root exudates led to a decrease in their number. These results emphasize the substantial impact of plant root exudates on soil microbial community responses to temperature, underscoring the necessity for future climate change research to incorporate additional environmental variables.

The Soil Microbiomes of American Ginseng (Panax quinquefolius) Cultivated in North America Differ by Location but Not Always by Disease Status

One of the greatest challenges faced by ginseng producers is control of fungal pathogens that adversely affect harvest yields and are a contributing factor to replant failure syndrome. The goal of this project was to survey the soil microbiome of healthy versus diseased American ginseng grown in North America. Soils associated with healthy and diseased plants were collected from commercial farms in Garett County, Maryland, and Marathon County, Wisconsin. Environmental DNA metabarcoding was used to compare the bacterial and fungal microbiomes of healthy versus diseased plants from both locations. The most common bacteria occurred within the phylum Proteobacteria, Firmicutes, and Bacteroidota and the most common fungi occurred within Ascomycota, Basidiomycota, Mortierellomycota, and Glomeromycota. Overall, alpha- and beta-diversities were statistically significant between the two locations. Community analyses (beta-diversity) of the Maryland site revealed a significant difference in the bacterial composition of soils associated with healthy versus diseased plants but not in the fungi. Conversely, there was a significantly different assemblage of fungi in healthy versus diseased associated soils from the Wisconsin site, but not for bacteria. Our results, when compared to previous metabarcoding studies, suggest that there is little congruence between the soil microbiomes associated with cultivated ginseng and that we are still in the early stages of ginseng soil rhizosphere exploration. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Seasonal variations in soil microbial community co-occurrence network complexity respond differently to field-simulated warming experiments in a northern subtropical forest

Global warming may reshape seasonal changes in microbial community diversity and co-occurrence network patterns, with significant implications for terrestrial ecosystem function. We conducted a 2-year in situ field simulation of the effects of warming on the seasonal dynamics of soil microbial communities in a northern subtropical Quercus acutissima forest. Our study revealed that warming had no significant effect on the richness or diversity of soil bacteria or fungi in the growing season, whereas different warming gradients had different effects on their diversity in the nongrowing season. Warming also changed the microbial community structure, increasing the abundance of some thermophilic microbial species and decreasing the abundance of some symbiotrophic microorganisms. The co-occurrence network analysis of the microbial community showed that warming decreased the complexity of the intradomain network in the soil bacterial community in the growing and nongrowing seasons but increased it in the fungal community. Moreover, increasing warming temperatures increased the complexity of the interdomain network between bacteria and fungi in the growing season but decreased it in the nongrowing season, and the keystone species in the interdomain network changed with warming. Warming also reduced the proportion of positive microbial community interactions, indicating that warming reduced the mutualism, commensalism, and neutralism of microorganisms as they adapted to soil environmental stress. The factors affecting the fungal community varied considerably across warming gradients, with the bacterial community being significantly affected by soil temperature, MBC, NO3−-N and NH4+-N, moreover, SOC and TN significantly affected fungal communities in the 4 °C warming treatment. These results suggest that warming increases seasonal differences in the diversity and complexity of soil microbial communities in the northern subtropical region, significantly influencing soil dynamic processes regulating forest ecosystems under global warming.

Soil fungal communities associated with chili pepper respond to mineral and organic fertilization and application of the biocontrol fungus Trichoderma harzianum

Soil fungi are diverse and common in crop systems with important ecological function such as saprotrophs, symbionts, and pathogens, all of which are key components for soil fertility and health. Agricultural practices including tillage, crop rotation, fertilization and pest management with pesticides and microbial biocontrol agents are known to affect the abundance and composition of soil fungi, but these factors are seldom integrated and studied in combination. The objective of this study was to examine the influence of mineral and organic (compost) fertilization, and soil inoculation with the biocontrol fungus Trichoderma harzianum individually and in combination on the resident soil fungal communities and plant performance in a greenhouse pot experiment with chili pepper grown in a disease-infested agricultural soil. Soil fungal communities were studied using Illumina MiSeq sequencing and taxonomic assignment using the UNITE database in terms of amplicon sequence variants (ASV). Main results showed that the combination of compost and T. harzianum inoculation completely controlled chili pepper wilt, which coincided with alterations in soil fungal diversity. The root pathogen Fusarium equiseti was the most abundant fungus (in relative terms) in all treatments and the ASV Trichoderma sp. was only found in the treatments in which T. harzianum had been applied. Soil application with T. harzianum at sowing also reduced chili pepper damping-off in non-sterile disease-infested soil, which coincided with a reduction of the relative abundance of F. equiseti. However, several other known Fusarium spp. pathogens were present in the natural disease infested agricultural soil and could also have been involved in the chili pepper wilt observed. In conclusion, our results show promising biocontrol traits of T. harzianum against chili pepper damping off and wilt most likely caused by Fusarium spp. The observed alterations in soil fungal diversity with T. harzianum and compost were probably involved in the reduction of chili pepper wilt but needs to be further studied.

After-sealing life in urban soils: Experimental evidence of resilience and efficiency of ectomycorrhizal inoculation

The restoration of urban sealed soils is a major stake for urban planners. In particular, characterizing their resilience from a biotic perspective is of primary importance for remobilizing these artificialized substrates in urban green spaces. Using Marseille (France) as a case study, we implemented a metabarcoding next generation sequencing approach to characterize the diversity and the composition of ectomycorrhizal (EM) fungal communities present in soils sealed for 60 years. Based on an inoculation experiment, we tested the ability of the remaining spore bank to establish EM interactions with plants. Altogether, we aimed at assessing the potential of peri-urban natural habitats to provide an efficient soil EM inoculum for the restoration of urban soils. We found that: (i) long-term sealing drastically reduced the diversity of EM fungi in urban soils, (ii) long-leaved spores of hypogeous gastroid fungi were efficient to establish EM symbioses with plants, and (iii) the efficiency of EM fungal inoculation depended on the natural habitat used as an inoculum source. Oak forests provided species-rich but poorly efficient inoculum. Contrastingly, soils collected in disturbed shrublands (garrigues) hosted moderately-rich EM communities containing droughtadapted species with high ability to colonize urban soils. Our findings highlight that peri-urban landscapes are promising candidates to feed local systems of urban soil restoration. In this perspective, poorly-considered habitats such as shrublands can be considered as valuable sources of soil biota to prevent the over-exploitation of agricultural areas.

An eco-friendly approach harnessing Trichoderma lixii ORT2 for reducing chemical phosphatic fertilizer dependency and groundwater phosphorus management through integrated in silico, in vitro and omic studies

Groundwater pollution has become an escalating global issue, with excessive application of phosphorus (P) fertilizers emerging as a major contaminant. The overuse of chemical phosphatic fertilizers has intensified the problem of P infiltration into water table, compromising soil health and exacerbating groundwater pollution. This underscores the urgent need to explore sustainable alternatives to chemical fertilizers to safeguard groundwater and soil health. The enzyme alkaline phosphatase (ALP) plays important role in efficient P-solubilization achieved by Trichoderma sp. a soil fungus known for its gradual transportation of P from fixed sources to plants. This mechanism not only minimizes P leaching into groundwater but also reduces dependency on fertilizers. To investigate the active role of fungal ALP in P-solubilization, amino acid/gene sequences of enzyme from 20 Trichoderma strains were retrieved from NCBI. Molecular docking revealed strong catalytic interaction (−6.93 kcal/mol) between complex-bound P and the ALP, involving two hydrogen bonds and key residues Gln286 and Arg340. To confirm ALP-mediated P-solubilization, 12 newly isolated Trichoderma spp., were assessed in vitro using media amended with tri-calcium phosphate (TCP), zinc phosphate (Zn3(PO4)2), or ferric phosphate (FePO4) as sole phosphorus source. Trichoderma lixii ORT2 demonstrated highest P-solubilization, yielding 547.40 μg/mL phosphate from TCP, 538.6 μg/mL from Zn3(PO4)2, and 423.45 μg/mL from FePO4, in 72 h. Solubilization was accompanied by simultaneous expression of ALP and siderophore in the same aliquot. TCP induced maximum expression of ALP (9.47 U/mL), followed by Zn3(PO4)2 and FePO4 showing 8.65 and 5.64 U/mL, respectively, in culture filtrates at 72h, that was further confirmed through proteomic analysis. FESEM micrographs confirmed P binding and biosorption into fungal mycelia as P-globules. Furthermore, Cicer arietinum inoculated with Trichoderma lixii ORT2 bio-formulations showed significant enhancement in growth parameters in TCP amended soil as compared to di-ammonium phosphate (DAP). The integrated approach of microbial P-solubilization and further utilization by plants for their growth as major nutrients merges microbial and phyto-remediation to address sustainability issues related to the management of soil health and phosphorus contamination. This strategy aims to substitute chemical phosphatic fertilizers, which are significant contributors to rising dissolved total phosphorus (DTP) in groundwater. This approach directly supports SDG 6 by reducing P leaching and improving groundwater quality, ensuring sustainable water and sanitation management for all.

Effect of meddling ARBs on ARGs dynamics in fungal infested soil and their selective dispersal along spatially distant mycelial networks

During the recent times, environmental antibiotic resistance genes (ARGs) and their potential transfer to other bacterial hosts of pathogenic importance are of serious concern. However, the dissemination strategies of such ARGs are largely unknown. We tested that saprotrophic soil fungi differentially enriched antibiotic resistant bacteria (ARBs) and subsequently contributed in spatial distribution of selective ARGs. Wafergen qPCR analysis of 295 different ARGs was conducted for manure treated pre-sterilized soil incubated or not with selected bacterial-fungal consortia. The qPCR assay detected unique ARGs specifically found in the mycosphere of ascomycetous and basidiomycetous fungi. Both fungi exerted potentially different selection pressures on ARBs, resulting in different patterns of ARGs dissemination (to distant places) along their respective growing fungal highways. The relative abundance of mobile genetic elements (MGEs) was significantly decreased along fungal highways compared to the respective inoculation points. Moreover, the decrease in MGEs and ARGs (along fungal highways) was more prominent over time which depicts the continuous selection pressure of growing fungi on ARBs for enrichment of particular ARGs in mycosphere. Such data also indicate the potential role of saprotrophic soil fungi to facilitate horizontal gene transfer within mycospheric environmental settings. Our study, therefore, advocates to emphasize the future investigations for such (bacteria-fungal) interactive microbial consortia for potential (spatial) dissemination of resistance determinants which may ultimately increase the exposure risks of ARGs.

Long-term nitrogen deposition alters the soil bacterial community structure but has little effect on fungal communities

Subtropical Moso bamboo (Phyllostachys edulis) forests have become hot spots for nitrogen (N) deposition in China. However, the effect of long-term N deposition on the structure of soil microbial communities in different horizons of these forests remains unclear. To investigate the influence of extended N deposition on soil bacteria and fungi, a simulated N deposition field study was conducted in Fujian Province with four N deposition levels (0, 20, 40 and 80 kg N hm−2 a−1). The absolute abundances, diversity, community structure, and potential functions of soil bacteria and fungi were investigated after 10 years of simulated N deposition. The results indicated that there was no significant effect of N deposition on the abundance or diversity of soil microbes in either the organic or mineral horizons of Moso bamboo forests. However, under rates of 40 and 80 kg N hm−2 a−1, long-term N deposition altered the structure of the soil bacterial community in the organic horizon. Specifically, there was a 27.75∼36.40 % increase in the relative abundance of Actinobacteria, while that of Acidobacteria decreased by 24.40∼27.52 %. Redundancy analysis (RDA) demonstrated that soil total carbon (TC) was the key variable influencing the bacterial community structure in the organic horizon. Analysis of potential microbial functions showed that in the organic horizon, the rates of chemoheterotrophy significantly decreased under 80 kg N hm−2 a−1. However, N deposition did not noticeably impact the fungal community structure in either soil horizon. Our study suggested that under 10 years of N deposition, only the bacterial community composition and function in the organic horizon was affected, indicating that soil bacteria are more sensitive to N deposition than fungi in subtropical Moso bamboo forests. Therefore, further research is necessary to fully understand the impact of N deposition on fungal community composition in the soil organic horizon and on the microbial community in the mineral horizon of subtropical bamboo forests. This study provides valuable insights for informing future environmental management and conservation strategies.

Response of soil fungal communities and their co-occurrence patterns to grazing exclusion in different grassland types.

Overgrazing and climate change are the main causes of grassland degradation, and grazing exclusion is one of the most common measures for restoring degraded grasslands worldwide. Soil fungi can respond rapidly to environmental stresses, but the response of different grassland types to grazing control has not been uniformly determined. Three grassland types (temperate desert, temperate steppe grassland, and mountain meadow) that were closed for grazing exclusion for 9 years were used to study the effects of grazing exclusion on soil nutrients as well as fungal community structure in the three grassland types. The results showed that (1) in the 0-5 cm soil layer, grazing exclusion significantly affected the soil water content of the three grassland types (P < 0.05), and the pH, total phosphorous (TP), and nitrogen-to-phosphorous ratio (N/P) changed significantly in all three grassland types (P < 0.05). Significant changes in soil nutrients in the 5-10 cm soil layer after grazing exclusion occurred in the mountain meadow grasslands (P < 0.05), but not in the temperate desert and temperate steppe grasslands. (2) For the different grassland types, Archaeorhizomycetes was most abundant in the montane meadows, and Dothideomycetes was most abundant in the temperate desert grasslands and was significantly more abundant than in the remaining two grassland types (P < 0.05). Grazing exclusion led to insignificant changes in the dominant soil fungal phyla and α diversity, but significant changes in the β diversity of soil fungi (P < 0.05). (3) Grazing exclusion areas have higher mean clustering coefficients and modularity classes than grazing areas. In particular, the highest modularity class is found in temperate steppe grassland grazing exclusion areas. (4) We also found that pH is the main driving factor affecting soil fungal community structure, that plant coverage is a key environmental factor affecting soil community composition, and that grazing exclusion indirectly affects soil fungal communities by affecting soil nutrients. The above results suggest that grazing exclusion may regulate microbial ecological processes by changing the soil fungal β diversity in the three grassland types. Grazing exclusion is not conducive to the recovery of soil nutrients in areas with mountain grassland but improves the stability of soil fungi in temperate steppe grassland. Therefore, the type of degraded grassland should be considered when formulating suitable restoration programmes when grazing exclusion measures are implemented. The results of this study provide new insights into the response of soil fungal communities to grazing exclusion, providing a theoretical basis for the management of degraded grassland restoration.

Biogeography and community assembly of soil fungi from alpine meadows in southwestern China show the importance of climatic selection

Soil fungi are pivotal in alpine and arctic ecosystems that are vulnerable to climate changes. Previous studies have shown broad connections between soil fungi in the arctic and alpine regions, but most of these studies are mainly from Europe and North America, with more sporadic studies from East Asia. Currently, little is known about the biogeographic relationships between soil fungi in alpine meadows of southwestern China (AMSC) and other regions of the world. In addition, the regional-scale spatial patterns of fungal communities in the AMSC, as well as their driving factors and ecological processes, are also poorly understood. In this study, we collected roots and surrounding soils of two dominant ectomycorrhizal plants, Bistorta vivipara and B. macrophylla from the AMSC, and performed bioinformatic and statistical analyses based on high-throughput sequencing of ITS2 amplicons. We found that: (1) fungi from the AMSC were closely related with those from boreal forests and tundra, and saprotrophic fungi had higher dispersal potential than ectomycorrhizal fungi; (2) community compositions exhibited clear divergences among geographic regions and between root and soil samples; (3) climate was the predominant factor driving regional-scale spatial patterns but had less explanatory power for saprotrophic and total fungi from roots than those from soils; (4) homogeneous selection and drift were the key ecological processes governing community assembly, but in communities of saprotrophic and total fungi from soil samples, drift contributed less and its role was partially replaced by dispersal limitation. This study highlights the importance of climatic selection and stochastic processes on fungal community assembly in alpine regions, and emphasizes the significance of simultaneously investigating fungi with different trophic modes and from both roots and soils.

Myco-fabricated silver nanoparticle by novel soil fungi from Saudi Arabian desert and antimicrobial mechanism

Biological agents are getting a noticeable concern as efficient eco-friendly method for nanoparticle fabrication, from which fungi considered promising agents in this field. In the current study, two fungal species (Embellisia spp. and Gymnoascus spp.) were isolated from the desert soil in Saudi Arabia and identified using 18S rRNA gene sequencing then used as bio-mediator for the fabrication of silver nanoparticles (AgNPs). Myco-synthesized AgNPs were characterized using UV–visible spectrometry, transmission electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering techniques. Their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae were investigated. In atrial to detect their possible antibacterial mechanism, Sodium dodecyl sulfate (SDS-PAGE) and TEM analysis were performed for Klebsiella pneumoniae treated by the myco-synthesized AgNPs. Detected properties of the fabricated materials indicated the ability of both tested fungal strains in successful fabrication of AgNPs having same range of mean size diameters and varied PDI. The efficiency of Embellisia spp. in providing AgNPs with higher antibacterial activity compared to Gymnoascus spp. was reported however, both indicated antibacterial efficacy. Variations in the protein profile of K. pneumoniae after treatments and ultrastructural changes were observed. Current outcomes suggested applying of fungi as direct, simple and sustainable approach in providing efficient AgNPs.

Distribution patterns of soil bacteria, fungi, and protists emerge from distinct assembly processes across subcommunities.

Environmental change exerts a profound effect on soil microbial domains-including bacteria, fungi, and protists-that each perform vital ecological processes. While these microbial domains are ubiquitous and extremely diverse, little is known about how they respond to environmental changes in urban soil ecosystems and what ecological processes shape them. Here we investigated the community assembly processes governing bacteria, fungi, and protists through the lens of four distinct subcommunities: abundant, conditionally rare, conditionally abundant, and rare taxa. We show that transient taxa, including the conditionally rare and conditionally rare or abundant taxa, were the predominant subcommunities. Deterministic processes (e.g., environmental filtering) had major roles in structuring all subcommunities of fungi, as well as conditionally rare and abundant protists. Stochastic processes had strong effects in structuring all subcommunities of bacteria (except rare taxa) and conditionally rare protists. Overall, our study underscores the importance of complementing the traditional taxonomy of microbial domains with the subcommunity approach when investigating microbial communities in urban soil ecosystems.

LbSakA-mediated phosphorylation of the scaffolding protein LbNoxR in the ectomycorrhizal basidiomycete Laccaria bicolor regulates NADPH oxidase activity, ROS accumulation and symbiosis development.

Ectomycorrhizal symbiosis, which involves mutually beneficial interactions between soil fungi and tree roots, is essential for promoting tree growth. To establish this symbiotic relationship, fungal symbionts must initiate and sustain mutualistic interactions with host plants while avoiding host defense responses. This study investigated the role of reactive oxygen species (ROS) generated by fungal NADPH oxidase (Nox) in the development of Laccaria bicolor/Populus tremula × alba symbiosis. Our findings revealed that L. bicolor LbNox expression was significantly higher in ectomycorrhizal roots than in free-living mycelia. RNAi was used to silence LbNox, which resulted in decreased ROS signaling, limited formation of the Hartig net, and a lower mycorrhizal formation rate. Using Y2H library screening, BiFC and Co-IP, we demonstrated an interaction between the mitogen-activated protein kinase LbSakA and LbNoxR. LbSakA-mediated phosphorylation of LbNoxR at T409, T477 and T480 positively modulates LbNox activity, ROS accumulation and upregulation of symbiosis-related genes involved in dampening host defense reactions. These results demonstrate that regulation of fungal ROS metabolism is critical for maintaining the mutualistic interaction between L. bicolor and P. tremula × alba. Our findings also highlight a novel and complex regulatory mechanism governing the development of symbiosis, involving both transcriptional and posttranslational regulation of gene networks.

Screening for the economic production of hydrolytic enzymes from locally-isolated fungi

Background Enzymes are complex proteins serving as biological catalysts to facilitate reactions in mild and environment-friendly conditions. Saprophytic fungi have long been harnessed for the efficient production of several industrially-significant enzymes whose market is still growing to cope with the increase in demand and natural resources’ depletion. Objective This investigation was performed with respect to the economic viewpoint of terrestrial fungi utilization and their hydrolytic enzymes’ biosynthetic potential. Materials and methods Several terrestrial fungi were isolated, cultivated on cheap agricultural wastes, and evaluated for industrial relevance. Solid-state fermentation was conducted to further boost the economic value and sustainability. The enzymatic productivity was estimated through solid-phase radial diffusion correlating the zones’ diameters to the enzymatic activity. Results and conclusion Six soil fungi were isolated, five belonging to the order Eurotiales and one to Mucorales. The molds belonged to four different genera; Aspergillus sydowii, Aspergillus versicolor, Aspergillus ustus, Fennelia flavipes (anamorph: Aspergillus flavipes), Cunninghamella elegans and Paecilomyces lilacinus. Many of the tested agricultural wastes were able to support the biosynthesis of the explored constitutive enzymes, recording better activity than the standard synthetic medium. Under the test conditions, L-asparaginase and protease were the most frequently detected enzymes while banana and mandarine peels led to the highest enzymes’ activity. In light of the global direction towards sustainability, enzymes can have immense prospects to sustain the industrial sectors innocuously. The cost-effectiveness of the manufacturing processes can be enhanced by accommodating the fiscal challenges for operating conditions. Using agrarian residues as raw material, highly productive enzyme producers, and cheaper solid-state fermentation processes are factors that may contribute to the efficacy, efficiency and economic feasibility of the enzyme-based processes.

Selection dictates the distance pattern of similarity in trees and soil fungi across forest ecosystems

Selection dictates the distance pattern of similarity in trees and soil fungi across forest ecosystems

Responses of soil fungal and bacterial communities to long-term organic and inorganic nitrogenous fertilizers in an alpine agriculture

Although nitrogen fertilizer is an important measure to increase grain yield, response of soil microbial community to nitrogen fertilizer is still unclear in alpine regions. Based on a long-term (>10 years) nitrogen fertilizer experiment (control, CF: chemical fertilizer, SM: sheep manure; CS: chemical fertilizer + sheep manure) in an alpine agroecosystem of the Lhasa, Xizang, responses of soil bacteria and fungi communities to nitrogen fertilizer was investigated. The CF treatment reduced fungi operational taxonomic unit (OTU) by 13.08 %, phylogenetic diversity by 11.13 % at 10–20 cm, but increased fungi guild number at 0–10 cm by 17.71 %. The SM treatment reduced fungi OTU at 10–20 cm by 11.82 %. Compared to CF and SM treatments, CS treatment had stronger positive effects on bacterial α-diversity, considering that CS treatment but not CF and SM treatments increased bacterial mean nearest taxon distance, species Shannon and Simpson at 10–20 cm. The CF, SM and CS treatments altered fungal community composition at 0–10 and 10–20 cm, bacterial community composition at 10–20 cm, and bacterial species composition at 0–10 cm. The CF and CS treatments altered bacterial phylogenetic composition at 0–10 cm, and the SM and CS treatments altered bacterial functional composition at 0–10 cm. The decreased magnitude of the relative abundance of symbiotroph fungi caused by CS treatment (90.44 %) was stronger than that (65.14 % and 53.62 %) caused by CF and SM treatments at 10–20 cm. Therefore, the SM and CS treatments had stronger effects on soil bacterial functional composition, but the CF treatment had stronger effects on fungal α-diversity. Compared with single application of organic or inorganic nitrogen fertilizer, mixed application of organic and inorganic nitrogen fertilizer was more beneficial to the maintenance and improvement of soil bacterial diversity, but caused more reduction of soil symbiotic fungi and in turn greater potential risk. These scientific findings observed by this study can provide guidance for fertilizer management and soil fertility improvement.

Surveying the Distribution and Diversity of Predominant Mycobiota in Cultivated and Uncultivated Soils of Zaria, Northwestern Nigeria

Study’s Novelty/Excerpt This study presents a comprehensive survey of the distribution and diversity of soil fungi in cultivated and uncultivated soils of Zaria, Northwestern Nigeria, highlighting their morphological and microscopic characteristics, frequency, and relationship with physicochemical properties. It identifies and quantifies the presence of eight different fungal species, with Aspergillus niger being the most dominant, providing critical insights into the fungal biodiversity of this region. Additionally, the study correlates the richness of soil mycobiota with specific soil properties such as pH, organic matter content, and moisture levels, suggesting that these factors significantly influence fungal diversity and distribution, and recommending further research to assess their impact on soil productivity. Full Abstract Soil fungi are a crucial component of terrestrial ecosystems, playing a vital role as decomposers in nutrient cycles. The diversity of soil fungi serves as an indicator of soil health (favorable/deficient). Understanding soil biodiversity and its biological functioning will help not only in crop yields but also in a healthier society as it directly or indirectly enters the food chain. This study aimed at surveying the distribution and diversity of predominant mycobiota in cultivated and uncultivated soils of Zaria, Northwestern Nigeria. Focusing on their morphological and microscopic characteristics, percentage frequency, and relationship with physicochemical properties. After removing the surface soil, soil samples were randomly collected from two locations at 0-15 cm depths. Fungi were isolated via the dilution method on PDA. Previously established criteria were used to identify eight different fungal species: Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Fusarium spp., Mucor spp., Penicillium spp., Rhizopus spp., and Trichoderma spp. Aspergillus niger was the most dominant species, with a relative frequency of 26%, followed by Fusarium spp. and Rhizopus spp. With 18% and 17%, respectively. Aspergillus fumigatus was the least abundant (2%). The highest fungal isolation frequency (32%) was observed in L1 cultivated soil, closely followed by L2 uncultivated soil (31%), with the lowest in L2 uncultivated soil (16%). Physicochemical analysis indicated that these soils are rich in mycobiota, attributed to a basic pH range of 7.12-9.15, high organic matter content, and optimal moisture levels. Soils with significant organic matter due to litter accumulation, moist deciduous vegetation, and neutral to alkaline pH levels retain considerable moisture content, fostering a rich qualitative and quantitative mycobiota for recycling dead organic matter making nutrients available for suitable utilization. Further research is recommended to evaluate the impact of these isolated fungi on soil productivity, to determine whether their presence has a positive or negative effect.