Soil Fungi Research Articles

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.

Enzyme Screening and Optimization from Coastal Soil Fungi of Dhanushkodi

Enzyme Screening and Optimization from Coastal Soil Fungi of Dhanushkodi

Влияние химических фунгицидов на содержание почвенных микромицетов в агроценозе рапса ярового в центральной зоне Краснодарского края

Different soil fungi infect many agricultural crops. They cause infectious diseases of plants and can be a serious threat for crop yield that leads to significant losses in the agricultural economics all over the world. Currently, a chemical method of Brassicaceae oil crops protection is the most spread. An important technique of this method is presowing seed treatment decreasing a level of internal and external infections. Fungicides must be both effective against diseases and environmentally friendly. Currently, there is no unequivocal opinion how the chemical fungicides influence on soil microflora. The purpose of the research was to study impact of some seed protectants on an amount of suppressor fungi from species Trichoderma Pers. and pathogenic fungi from species Fusarium Link. in soil in spring rapeseed agrocenosis. The research was conducted at the V.S. Pustovoit All-Russian Research Institute of Oil Crops in 2020–2022. Before sowing, the seeds were treated with protectants with active ingredients: thiram, WSC (400 g/l) (etalon), carboxin + thiram, WSC (200 + 200 g/l), imazalil + tebuconazole, OE (100 + 60 g/l), and fludioxonil, SC (25 g/l). Soil was sampled before planting of treated rapeseed seeds and in crop phases of 2–4 true leaves and yellow pods. The soil layer from 0 to 10 cm was studied as it contains the most amount of lateral roots of this crop. To the rapeseed maturation, amounts of suppressor fungi in variants with application of preparations was at the level of the control; it increased by 1.8–2.4 × 103 CFU/g and reached 7.3–8.0 × 103 CFU/g, maximal meaning was in variant with an active ingredient fludioxonil (25 g/l). The amount of pathogenic micromycetes Fusarium spp. was by 1.7–2.0 times lower the control to the rapeseed maturation in variants with application of preparations.

Diversity of soil fungi and entomopathogenic fungi in subtropical mountain forest in southwest China

AbstractTill now, the diversity of entomopathogenic fungi in subtropical mountain forest was less studied. Here, the vertical distribution of forest soil fungi, entomopathogenic fungi, and their environmental influencing factors in a subtropical mountain in western China were investigated. Soil samples were collected from four elevations in a subtropical forest in Shaanxi. The results indicated a greater richness of soil fungi at middle elevations and soil fungi were more even at low elevation. Soil pH, available iron, available potassium, total potassium, and available zinc were the most important influencing factors affecting this vertical distribution of fungi. Interestingly, the Isaria genus was predominant while Metarhizium and Beauveria showed decreasing abundance. The presence of Isaria showed a significant positive correlation with both total phosphorus and available iron, while, available zinc was negatively correlated. Metarhizium was influenced by elevation, pH, available phosphorus, and available copper and Beauveria was influenced by soil organic carbon, total nitrogen, total potassium, available potassium, and available zinc. Overall, as environmental factors affecting soil fungi, elevation, and plant species diversity were less important than soil physical and chemical properties. The virulence of isolated entomopathogenic fungi were tested against larvae of Tenebrio molitor, with mortality ranging from 31.11% to 100%. The above findings provide valuable data to deepen our understanding of the diversity of entomopathogenic fungi in subtropical mountain forests.

The spatio-temporal accumulation of 6 PPD-Q in greenbelt soils and its effects on soil microbial communities

6 PPD-Q (6 PPD-Quinone) is an ozone-induced byproduct derived from the degradation of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6 PPD), commonly found in road dust resulting from tire wear. However, the extent of 6 PPD-Q pollution in urban soil remains unclear. This study investigates the spatial and temporal accumulation patterns of 6 PPD-Q in greenbelt soils in Ningbo, and explores the correlation between 6 PPD-Q accumulation and soil microbial community composition and functions. Our findings indicate that 6 PPD-Q is present (ranging from 0.85 to 12.58 μg/kg) in soil samples collected from both sides of urban traffic arteries. Soil fungi exhibit higher sensitivity to 6 PPD-Q accumulation compared to bacteria, and associated fungi (Basidiomycota) may be potential biomarkers for environmental 6 PPD-Q contamination. Co-occurrence network analysis reveals that the bacterial microbial network in summer exhibits greater stability and resilience in response to 6 PPD-Q inputs than in winter. However, 6 PPD-Q accumulation disrupts the network structure of fungal communities to some extent, leading to reduced diversity in fungal microbial communities. Long-term accumulation of 6 PPD-Q weakens the nitrogen and phosphorus cycling potential within urban soil, while the enhancement of carbon cycling may further promote 6 PPD-Q degradation in urban soil. Taken together, this study provides new insights into the ecological risks of 6 PPD-Q in urban soils.

Microbial Carriage of Shuttle Door Handles and Campus Bank’s Automated Teller Machines

Microorganisms are ubiquitous organisms that can cause microbial contamination in both indoor and outdoor settings, with frequently touched surfaces acting as environmental reservoirs that increase the ability of pathogens to be transferred from host to host. This study was aimed at isolating, identifying and characterizing bacteria and fungi present on frequently used Automated Teller Machines (ATMs) and campus shuttle bus handles at Adekunle Ajasin University, Akungba-Akoko, Ondo State. Swab samples were obtained from the keypads of ATMs and door handles of campus shuttle buses. Enumeration of total microbial counts was carried out using the pour plating technique. The bacterial isolates were identified using Bergey's Manual of Determinative Bacteriology based on the results obtained from microscopic examination, cultural and morphological examination and biochemical tests. Meanwhile, the fungal isolates were identified using the Atlas and Compendium of Soil Fungi, based on the results obtained from cultural and morphological examination, as well as microscopic examination. The antibiotic and antifungal susceptibility pattern of the isolated microorganisms was also determined. Results showed that the ATM keypads and shuttle door handles contained Staphylococcus aureus (8.82%), Bacillus spp. (32.35%), Proteus mirabilis (8.82%), Escherichia coli (5.88), Salmonella spp. (5.88%), Enterobacter cloacae (5.88%), Klebsiella pneumoniae (2.94%), Citrobacter freundii (2.94%), Vibrio cholerae (2.94%), Serratia marcescens (2.94%), Aspergillus spp. (5.88%), Cladosporium sp. (2.94%), Geomyces sp. (2.94%), Oidiodendron griseum robak (2.94%), Penicillium paneum (2.94%) and Fusarium culmorum (2.94%). The zone of inhibition for the bacteria and fungi isolates ranged from 4mm to 36 mm, with ciprofloxacin being the most effective antibiotic. This study shows that campus shuttles and ATMs, aside from their primary functions, could also serve as a means of transmitting both pathogenic and non-pathogenic microorganisms, which pose public health risks. Personal hygiene and sanitation, such as hand washing and the use of hand sanitizer to clean hands, could serve as a means of reducing the incidence of microbial transmission.

Soil Fungal Community Differences in Manual Plantation Larch Forest and Natural Larch Forest in Northeast China.

Soil fungal communities are pivotal components in ecosystems and play an essential role in global biogeochemical cycles. In this study, we determined the fungal communities of a natural larch forest and a manual plantation larch forest in Heilongjiang Zhongyangzhan Black-billed Capercaillie Nature Reserve and Gala Mountain Forest using high-throughput sequencing. The interactions between soil fungal communities were analysed utilising a co-occurrence network. The relationship between soil nutrients and soil fungal communities was determined with the help of Mantel analysis and a correlation heatmap. The Kruskal-Wallis test indicated that different genera of fungi differed in the two forest types. The results show that there was a significant change in the alpha diversity of soil fungal communities in both forests. In contrast, nonmetric multidimensional scaling (NMDS) analysis showed significant differences in the soil fungal community structures between the manual plantation larch forest and the natural larch forest. The soil fungal co-occurrence network showed that the complexity of the soil fungal communities in the manual plantation larch forest decreased significantly compared to those in the natural larch forest. A Mantel analysis revealed a correlation between the soil fungal co-occurrence network, the composition of soil fungi, and soil nutrients. The RDA analysis also showed that AN, TK, and pH mainly influenced the soil fungal community. The null model test results showed the importance of stochastic processes in soil fungal community assembly in manual plantation larch forests. Overall, this study enhances our understanding of the differences in soil fungal communities in manual plantation larch forests and natural larch forests, providing insights into their sustainable management. It also serves as a reminder that the ecological balance of natural ecosystems is difficult to restore through human intervention, so we need to protect natural ecosystems.

Functional composition of initial soil fungi explains the difference in mass loss of Phragmites australis litter in different habitat conditions across multiple coastal wetlands

The differences in mass loss of leaf litter are primarily thought to be driven by microbial activity, especially by fungi. However, the existence of such differences across large spatial scales has not been well explored in field studies and the underlying mechanisms of difference are still unclear, especially for the role of different fungal guilds in driving different mass losses. We conducted a 1-year decomposition study within each of four coastal wetlands in China to test the difference in mass loss across a large spatial scale (ranging from 26° N to 41° N in latitude). In each wetland, six sites including three composed of P. australis and three composed of another dominant plant species typically in coastal ecosystems were selected. We used P. australis leaf litter as the standard decomposition material, placing it into litter bags with mesh sizes 1 mm and 4 mm, respectively. Final litter mass loss was examined approximately after 3, 9 and 12 months. The different mass loss was quantified using additional mass loss at P. australis sites compared to that at another species sites. We found that the mass loss of leaf litter of P. australis showed a clear difference across multiple coastal wetlands only at later stages of decomposition, which was independent of mesofauna (mesh size) contribution to decomposition. Furthermore, the observed difference in mass loss was primarily attributed to the dissimilarities in initial soil fungal community, particularly the symbiotrophic fungi, rather than the soil bacterial community. Our results provide empirical evidence of a large-scale difference in mass loss in litter decomposition and have linked the observed difference to different soil fungal guilds. These results indicate that symbiotrophic fungi might play a direct or indirect role in driving difference in mass loss, which contributes to a better understanding and invites in-depth further investigation on the underlying microbe-driven mechanisms of the difference.

Synthesis and investigation of nano-biologic structures’ effect on soil pathogenic fungi in maize

Maize soil pathogenic fungi, Fusarium moniliforme, Macrophomina phaseolina, and Rhizoctonia zeae are important causes of annual economic losses worldwide. Since there are no maize cultivars with complete resistance to soil-borne fungal pathogens. This study aims to produce highly effective Nano-formulations of Peganum harmala and Ailanthus altissima plant extracts to control maize soil fungi. The GC-MS, DLS, Zeta, TEM, SEM, FTIR, disease symptoms, fresh and dry weights, Catalase, and Peroxidase enzymes were measured under in-vitro and in-vivo conditions. Harmine and Quercetin were the most common compounds in the extracts. The obtained results showed that the particles were spherical and encapsulated on a nanoscale. The in-vitro results showed that the best treatment for the F. moniliforme, M. phaseolina, and R. zeae fungi was P. harmala Nanoemulsion at 20 % concentration with 78.7 % inhibition. Maize seed priming with 20 % P. harmala Nanoemulsion showed the highest fresh and dry weights of 75.2 and 25.2 g, respectively, with minimal disease symptoms. The highest activity of Catalase and Peroxidase, 6.2 and 2.4 U mg protein−1 min−1, respectively.

Tobacco crop rotation enhances the stability and complexity of microbial networks.

The effects of continuous cropping and rotation cropping, two important tobacco cultivation practices, on soil microbial communities at different stages remain unclear. Different planting patterns have been shown to influence soil physical and chemical properties, which in turn can affect the composition and diversity of soil microbial communities. In order to investigate the impact of different planting methods on soil microbial community structure, we selected two representative planting methods: continuous cropping (tobacco) and rotational cropping (tobacco-maize). These methods were chosen as the focal points of our research to explore the potential effects on soil microbial communities. High-throughput sequencing technology was employed to investigate the structure of soil microbial communities, as well as their relationships with soil environmental factors, by utilizing the 16S rRNA, ITS, and 18S genes. Furthermore, the interaction among microorganisms was explored through the application of the Random Matrix Theory (RMT) molecular ecological network approach. There was no significant difference in α diversity, but significant difference in β diversity based on Jaccard distance test. Compared to continuous cropping, crop rotation significantly increased the abundance of beneficial prokaryotes Verrucomicrobia and Rhodanobacter. These findings indicate that crop rotation promotes the enrichment of Verrucomicrobia and Rhodanobacter in the soil microbial community. AP and NH4-N had a greater effect on the community structure of prokaryotes and fungi in tobacco soil, while only AP had a greater effect on the community structure of protist. Molecular ecological network analysis showed that the network robustness and Cohesion of rotation were significantly higher than that of continuous cropping, indicating that the complexity and stability of molecular ecological networks were higher in the rotational, and the microbial communities cooperated more effectively, and the community structure was more stable. From this point of view, rotational cropping is more conducive to changing the composition of soil microbial community, enhancing the stability of microbial network structure, and enhancing the potential ecological functions in soil.

Rotation with other crops slow down the fungal process in tobacco-growing soil

Continuous cultivation of tobacco could cause serious soil health problems, which could cause bacterial soil to change to fungal soil. In order to study the diversity and richness of fungal community in tobacco-growing soil under different crop rotation, three treatments were set up in this study: CK (tobacco continuous cropping); B (barley-tobacco rotation cropping) and R (oilseed rape-tobacco rotation cropping). The results of this study showed that rotation with other crops significantly decreased the soil fungal OTUs, and also decreased the community richness, evenness, diversity and coverage of fungal communities. Among them, B decreased the most. In the analysis of the composition and structure of the fungal community, it was found that the proportion of plant pathogens Nectriaceae decreased from 19.67% in CK to 5.63% in B, which greatly reduced the possibility of soil-borne diseases. In the analysis of the correlation between soil environmental factors and fungal communities, it was found that Filobasidiaceae had a strong correlation with TP and AP, and Erysiphaceae had a strong correlation with TK and AK. NO3−-N and NH4+-N were the two environmental factors with the strongest correlation with fungal communities. The results of this study showed that rotation with other crops slowed down the process of soil fungi in tobacco-growing soil and changed the dominant species of soil fungi community. At the same time, crop rotation changed the diversity and richness of soil fungal community by changing the physical and chemical properties of soil.

Unlocking the promising potential: Trichoderma TrB (CNCM strain I-5327) in Golf course management

In the pursuit of sustainable turfgrass management for golf courses, a series of experiments was conducted to assess the potential of Trichoderma TrB (CNCM strain I-5327) as a natural solution. The research encompassed greenhouse and field trials across two golf courses. The comprehensive pot experiment investigated Trichoderma effectiveness, including native (TrB) and commercial strains, with and without organic amino acids, for turfgrass and soil health. The study followed a two-stage process, stimulating beneficial microorganisms with TrB and introducing Fusarium for biocontrol. Preliminary field trial on one golf course utilized a randomized block design to examine the effects of TrB and Trianum with amino acids, and fungicide on soil microbial community. A second field trial analyzed soil metabolic profiles after applying TrB, Trianum, and fungicide on another golf course. The greenhouse experiments demonstrated promising outcomes from the application of TrB, especially when combined with organic amino acids. This combination not only promoted plant growth and improved soil health but also effectively prevented the activation of Fusarium. In both field trials, it was observed that the introduction of TrB into the soil led to an increase in the population of soil fungi and bacteria and stimulated their activity. Our field data revealed that enriching the soil with TrB had a positive effect on soil microbial communities, while the application of fungicide resulted in a decrease in microbial activities. In summary, our research underscores Trichoderma's potential (TrB) in sustainable golf course management. These findings highlight TrB as a promising natural solution for improving turfgrass health and soil quality in sustainable management of golf course.

Climate and land use primarily drive the diversity of multi-taxonomic communities in agroecosystems

To successfully conserve and restore agrobiodiversity, it is essential to understand the impact of multiple drivers and interlinkages across multiple taxa that occur above, across, and below the soil interface. Based on data from six agricultural landscapes in Central Germany, with 16 sampling plots per landscape, we used structural equation models to disentangle the impacts of climate, land-use, and soil factors on the diversity of multiple taxonomic groups. We expected belowground communities (soil bacteria and fungi) to be more driven by soil variables, mobile aboveground groups (wild bees, ground beetles) to be more driven by climate and land use, and vascular plants, that have an above- and belowground component, to respond to a combination of all factors.According to our expectations, climate and land-use variables had an important role in shaping aboveground and plant communities. In contrast to our expectations, soil characteristics were of lesser importance for belowground organisms. Moreover, climatic factors had a strong impact on the soil microbiome, but this effect was indirect, modulated by soil pH. We also found indications for cascading effects of environmental factors via interlinkages within and among the above- and belowground communities. Our results highlight the importance of direct and indirect effects of multiple drivers on the diversity of multiple taxonomic groups and support recent calls for a multifunctional approach for sustainable landscape management and nature restoration, suggesting to focus on the promotion of semi-natural habitats but also considering the climatic context.

Manipulating soil resource availability to alter microbial communities for weed management in agroecosystems

The growing resistance of weeds to herbicides demands innovative strategies that harness soil biology for effective weed control. We examined the use of carbon amendments to stimulate microbial immobilization of soil nitrogen for weed control. We hypothesized that increased carbon availability will stimulate soil microbial growth, leading to greater nitrogen immobilization, which consequently decreases plant-available nitrogen and suppresses the growth of nitrogen-responsive weed species. We buried 80 19-L pots in a research farm field and added sawdust and sucrose to soils as a high carbon treatment and used unamended soils as a control. We examined eight different weed species separately, and measured plant growth, soil carbon, available nitrate, microbial carbon and nitrogen, and microbial community composition after 11 weeks of treatment. The carbon amendments altered plant-microbial competition for nitrogen, resulting in reduced biomass for most weed species. The carbon-amended soils had higher microbial biomass carbon and nitrogen, slower nitrogen cycling, and less available soil nitrogen, indicating enhanced nitrogen immobilization. The carbon treatment altered the beta diversity of soil fungi and bacteria and reduced fungal alpha diversity estimated by the Shannon index. The study results indicate that high carbon substrates can be used to modify plant-microbial competition for soil nitrogen with important implications for developing sustainable weed management practices.

Cations impact the biodegradation of iodosulfuron-methyl herbicidal ionic liquids by fungi

ABSTRACT In the framework of this study, six fungal isolates which demonstrated a high capability for biodegrading iodosulphuron-methyl sodium as well as herbicidal ionic liquids based on this herbicide were isolated from different soil samples. The isolates were identified based on the ITS region, whereas biodegradation residues were determined based on LC-MS/MS. Depending on the isolate, the half-lives values of the biodegraded herbicide or herbicidal ionic liquid ranged significantly from just 1.25 days to more than 40 days. The research findings unveiled that the structure of cations is a central limiting factor affecting fungal growth and herbicide transformation in case of ionic liquids. The length of the alkyl chain has been identified as the primary driver of herbicide toxicity, emphasizing the importance of structural factors in herbicide design. In cases when dodecyl(2-hydroxyethyl)dimethyl cation was used, its biodegradation ranged from 0 to approx. 20% and the biodegradability of the iodosulfuron-methyl was notably limited for the majority of the studied isolates. This knowledge provides guidance for development and selection of herbicides with reduced environmental impact. This study highlights the ecological importance of soil fungi, their potential role in herbicide biodegradation, the influence of cations on fungal growth and herbicide transformation, and the structural factors governing herbicide toxicity. Further research in these areas may lead to more efficient and environmentally friendly approaches to herbicide management.

Defoliation modifies the impact of drought on the transfer of recent plant-assimilated carbon to soil and arbuscular mycorrhizal fungi

Abstract Aims The allocation of recent plant photosynthates to soil via arbuscular mycorrhizal (AM) fungi is a critical process driving multiple ecosystem functions in grasslands. Yet, our understanding of how defoliation modifies below-ground allocation of recent plant photosynthate and its response to drought, which is becoming more intense and frequent, remains unresolved. Methods Here we undertook a 13C pulse-labelling experiment in a mesotrophic temperate grassland to evaluate in situ how defoliation intensity modifies the transfer of recently assimilated 13C from plant shoots to roots, extraradical AM fungal hyphae, soil, and 13C-CO2 efflux (soil respiration) in response to simulated drought. Results We found that, individually, both defoliation and drought reduced initial plant 13C uptake, but when defoliation and drought were combined, we detected a significant reduction in below-ground 13C allocation to soil. Furthermore, while defoliation stimulated 13C transfer to plant roots and soil, high intensity defoliation amplified 13C-CO2 efflux relative to the amount of 13C taken up by plants. Drought stimulated 13C transfer to fungal hyphae relative to initial plant uptake. High intensity defoliation, however, suppressed both 13C enrichment of extraradical AM fungal hyphae and 13C transfer to fungal hyphae relative to initial uptake. Conclusions Our findings suggest that defoliation can reduce the transfer of recent photosynthate below-ground under simulated drought and provide new insights into how defoliation may influence grassland C allocation dynamics and cycling between plants and AM fungi in grasslands facing drought.