Saprophytic Fungi Research Articles

Enhancement of multiple antibiotics removal performance of different microalgae-based system by agricultural phytohormone and carboxylated multi-walled carbon nanotubes induction

Novel microalgae-based technologies for eight antibiotics removal are developed and characterized in the present study based upon the screened dominant strains Scenedesmus quadricauda (S. quadricauda), Chlorella ellipsoidea (C. ellipsoidea), exogenous supplementation of the agricultural multi-phytohormone composed of 0.135 % gibberellin acid, 0.00052 % indole-3-acetic acid as well as 0.00031 % brassinolide (GIB) and carboxylated multi-walled carbon nanotubes (MWCNT-COOH). Four microalgae-based systems were constructed by using S. quadricauda, C. ellipsoidea, endophytic bacterium (S395-2) and the saprophytic filamentous fungus Clonostachys rosea (C. rosea). The results demonstrated that C. ellipsoidea-S395-2- C. rosea symbiont under 10 mg L−1 GIB treatment had greatest growth rate, mean daily production, Chlorophyll a contents and highest antibiotics removal efficiencies of 99.05 ± 0.43 %, 95.45 ± 3.51 %, 99.61 ± 0.18 %, 76.07 ± 6.41 %, 74.09 ± 6.25 %, 77.53 ± 7.12 %, 81.13 ± 7.45 % and 75.43 ± 6.74 % for tetracycline hydrochloride (TC), oxytetracycline hydrochloride (OTC), chlorotetracycline (CTC), ciprofloxacin (CPFX), norfloxacin (NFX), sulfadiazine (SMZ), sulfamethazine (SMX) and sulfamethoxazole (SMM), respectively. Collectively, this work demonstrates that exogenously supplementing 10 mg L−1 GIB and 2 mg L−1 MWCNT-COOH can optimally and maximally enhance the biomass production, photosynthetic activity and multiple antibiotics removal rate of C. ellipsoidea-S395-2- C. rosea symbiotic culture, which provides the foundation for complex treatment of antibiotics-containing swine wastewater by three-phase symbiont supplemented with both agricultural multi-hormone and MWCNT-COOH.

Pre and Post Covid - 19 Experience of the 'Amphotericin Sandwich' Therapy in the Management of Mucormycosis.

Mucormycosis is caused by saprophytic fungi belonging to the species mucorales. The disease commonly affects patients with immunocompromised states such as uncontrolled diabetes, blood disorders and organ transplantation recepients. The usual mode of management is by using antifungals such as amphotericin B and surgery in the form of debridement of the necrotic tissue. A study was conducted on patients of mucormycosis during the pre-Covid-19 and Covid-19 era to evaluate the effectiveness of the Sandwich Therapy of amphotericin B. The mortality rate was found to be 3.57% during the pre- Covid-19 period and 18.8% during the Covid-19 period. This is very low as opposed to 50% quoted by many other studies. The Sandwich Therapy as discussed above for extensive mucormycosis can be useful in curtailing the disease already established to its present location and preventing its further spread either naturally or by the act of debridement per se. It also provides a sustained anti fungal umbrella in the blood to deal with the disease at microscopic level in the blood stream thus reducing mortality.

Curvature-Based Active Region Segmentation for Improved Image Processing of Aspergillus Species

Aspergillus is one of the most ubiquitous of the airborne saprophytic fungi that can withstand various climatic conditions and could cause multiple type of illness. It can be beneficial to humankind and also can be infectious to humans and animals. Direct microscopic is used by trained microscopist as one of the alternatives in identification process to any specimen that suspected of having fungal infection. Confirmation towards identification is often necessary as the structure of Aspergillus is complex and dissimilar in each cycle. In addition, the structure of some species of Aspergillus are the almost same, which can be incorrectly recognized. In prevention of misidentification, computer-based Aspergillus species identification is proposed. The detection process is the earliest and important process hence, this paper proposed an active region-based segmentation method in order to detect the presence of fungi. This method is literally not depending on the gradient or sharp edges of the object and implementing level set function for curve evolution which able to reduce the computational cost. Originally, this function was developed for tracking fluid interfaces but in this study, this function has been applied to fungi database. Two different methods were tested and compared to observe their ability to segment different 80 of Aspergillus images which included four species. Experiments conducted have been compared with the baseline technique and the proposed method is outperformed in terms of accuracy, specificity with average of 90% and PSNR value of greater than 40dB. Meanwhile the active contour (snake) was slightly underperformed but well performed particularly in terms of sensitivity with greater than 80% for all the species. Moreover, upon scrutinizing the dice coefficients provided in both tables, it becomes apparent that there is a lack of significant variance in the values, except in the instance of Aspergillus fumigatus (active region-based) that which produces a result below 36%.

Exploring the Potential of Russula griseocarnosa: A Molecular Ecology Perspective

Russula griseocarnosa, an edible and medicinal mushroom abundant in nutrients and notable bioactivities, is predominantly grown in the broad-leaved forest with trees of the family Fagaceae in southern China. This species forms ectomycorrhizal associations with plant roots and cannot be artificially cultivated currently. Previous research indicates a strong correlation between the growth of R. griseocarnosa and factors such as the host plant, climate variables (specifically mean temperature and precipitation from June to October), and the rhizosphere microbiota of its habitat. However, comprehensive studies on the fundamental biology of this species are lacking. The interaction between R. griseocarnosa and its host plant, as well as the mechanisms underlying the microbial community dynamics within its habitat, remain ambiguous. The limited repertoire and diversity of carbohydrate-active enzymes (CAZymes) in R. griseocarnosa relative to saprophytic fungi may contribute to its recalcitrance to cultivation on synthetic media. The specific core enzyme and the substances provided by the host plant to facilitate growth are yet to be elucidated, posing a significant challenge in the artificial cultivation of R. griseocarnosa. The habitat of R. griseocarnosa harbours unique microbial communities, indicating the presence of potentially beneficial microorganisms that could be exploited for artificial propagation and conservation efforts. However, the lack of definitive functional verification experiments hinders the realization of this promising prospect. This review offers a comprehensive overview of the nutritional profile and health benefits of R. griseocarnosa, emphasizing recent developments in its isolation, molecular ecology, and artificial cultivation. Additionally, it explores prospective advancements in R. griseocarnosa research, aiming to enrich our foundational understanding for applied purposes and fostering progress in the realm of ectomycorrhizal edible mushrooms.

Особенности формирования высокопродуктивного посева нового гибрида подсолнечника Фогор

Influence of seed sowing rates (40, 60 as control and 80 thousand seeds/ha) on productivity of sunflower hybrid Fogor was studied on leached black soils of the Western Ciscaucasia (Korenovsk district, Kranodar region) in 2022–2023. It is established the highest seed (3.62 t/hа) and oil (1.46 t/hа) yields are reached at the seed-sowing rate of 80 thousand seeds/ha under sufficient moisture supply. Under weather conditions of 2022–2023, the less prevalence of bacteriosis (by 2 and 13%) and rust (by 6 and 8%, respectively) in the crops were observed. In 2023, population of fungal micoflore in rhizosphere was high enough (5.5 × 104 CFU/g), at the control level (5.7 × 104 CFU/g), the most was presented by saprophyte fungi from genera Penicillium (55.3% of the total fungi amount) and Aspergillus (25.4%). But the share of pathogenic fungi was less significantly: Fusarium spp. – 4.5%, Rizopus spp. – 0.8%. Consequently, the highly productive crops of the new sunflower hybrid Fogor is formed under sufficient water supply at the seed-sowing rate of 80 thousand seeds/ha.

MicroRNA (miRNA) profiling of maize genotypes with differential response to Aspergillus flavus implies zma-miR156–squamosa promoter binding protein (SBP) and zma-miR398/zma-miR394–F -box combinations involved in resistance mechanisms

Maize (Zea mays), a major food crop worldwide, is susceptible to infection by the saprophytic fungus Aspergillus flavus that can produce the carcinogenic metabolite aflatoxin (AF) especially under climate change induced abiotic stressors that favor mold growth. Several studies have used “-omics” approaches to identify genetic elements with potential roles in AF resistance, but there is a lack of research identifying the involvement of small RNAs such as microRNAs (miRNAs) in maize-A. flavus interaction. In this study, we compared the miRNA profiles of three maize lines (resistant TZAR102, moderately resistant MI82, and susceptible Va35) at 8 h, 3 d, and 7 d after A. flavus infection to investigate possible regulatory antifungal role of miRNAs. A total of 316 miRNAs (275 known and 41 putative novel) belonging to 115 miRNA families were identified in response to the fungal infection across all three maize lines. Eighty-two unique miRNAs were significantly differentially expressed with 39 miRNAs exhibiting temporal differential regulation irrespective of the maize genotype, which targeted 544 genes (mRNAs) involved in diverse molecular functions. The two most notable biological processes involved in plant immunity, namely cellular responses to oxidative stress (GO:00345990) and reactive oxygen species (GO:0034614) were significantly enriched in the resistant line TZAR102. Coexpression network analysis identified 34 hubs of miRNA-mRNA pairs where nine hubs had a node in the module connected to their target gene with potentially important roles in resistance/susceptible response of maize to A. flavus. The miRNA hubs in resistance modules (TZAR102 and MI82) were mostly connected to transcription factors and protein kinases. Specifically, the module of miRNA zma-miR156b-nb – squamosa promoter binding protein (SBP), zma-miR398a-3p – SKIP5, and zma-miR394a-5p – F-box protein 6 combinations in the resistance-associated modules were considered important candidates for future functional studies.

Population dynamics of the brown planthopper (Nilaparvata lugens Stảl.) in rice fields and their association with the entomopthoralean fungus

The rice plant (Oryza sativa L.) is one of the primary food sources for Indonesian people. The Brown planthopper (BPH), Nilaparvata lugens is one of the most devastating rice insect pests in Indonesia. The entomopthoralean fungus, Pandora delphacis is reported to be able to infect BPH naturally in the rice field. This research aims to identify the entomopthoralean fungi phase and determine the level of fungal infection and its relations with the population dynamic of BPH in rice fields. This research was conducted in 2015 and 2016 on rice fields at Bogor Regency and Subang Regency; and in 2017 at Karawang Regency, West Java. The sampled BPH were collected from rice fields. The microscope slide squash mounts in lactophenol cotton blue were made for the insects and it was examined with a microscope compound to determine if hyphal bodies, conidiophore, primary conidia, secondary conidia, saprophytic fungi, and resting spores were present. The results showed that the entomopthoralean fungi phase found on BPH are hyphal bodies, primary conidia, secondary conidia, and saprophytic fungi. The fungus infected all the phases of the BPH, from the first nymphal phase to adult.

Response of Soil Fungal-Community Structure to Crop-Tree Thinning in Pinus massoniana Plantation

To address the ecological challenges arising from pure forest plantations and the wood supply–demand imbalance, implementing sustainable forest management is paramount. Accordingly, we studied crop trees at three densities (100, 150, and 200 N/ha) in a subtropical Pinus massoniana plantation. Our study revealed that the dominant phyla and genera within the fungal community remained largely consistent, with Basidiomycota and Ascomycota occupying prominent positions. Notably, the β diversity of the fungal community exhibited significant changes. Ectomycorrhizal and saprophytic fungi emerged as crucial functional guilds, and crop-tree thinning contributed to increased complexity within the fungal network, with a prevalence of positive rather than negative correlations among genera. The significant roles played by Camphor plants and ferns were evident in the fungal networks. Additionally, under crop-tree thinning, plant diversity experienced a significant boost, fostering interactions with the fungal community. Herb diversity played a vital role in the fungal community, affecting it either directly or indirectly, by altering the content of total phosphorus or organic matter in the soil. This study underscores the relationship between undergrowth plants and soil fungal communities, offering a scientific basis for evaluating the sustainability of restoring inefficient forest-plantation ecosystems.

Small GTPase Rab7 is involved in stress adaptation to carbon starvation to ensure the induced cellulase biosynthesis in Trichoderma reesei.

The saprophytic filamentous fungus Trichoderma reesei represents one of the most prolific cellulase producers. The bulk production of lignocellulolytic enzymes by T. reesei not only relies on the efficient transcription of cellulase genes but also their efficient secretion after being translated. However, little attention has been paid to the functional roles of the involved secretory pathway in the high-level production of cellulases in T. reesei. Rab GTPases are key regulators in coordinating various vesicle trafficking associated with the eukaryotic secretory pathway. Specifically, Rab7 is a representative GTPase regulating the transition of the early endosome to the late endosome followed by its fusion to the vacuole as well as homotypic vacuole fusion. Although crosstalk between the endosomal/vacuolar pathway and the secretion pathway has been reported, the functional role of Rab7 in cellulase production in T. reesei remains unknown. A TrRab7 was identified and characterized in T. reesei. TrRab7 was shown to play important roles in T. reesei vegetative growth and vacuole morphology. Whereas knock-down of Trrab7 significantly compromised the induced production of T. reesei cellulases, overexpression of the key transcriptional activator, Xyr1, restored the production of cellulases in the Trrab7 knock-down strain (Ptcu-rab7KD) on glucose, indicating that the observed defective cellulase biosynthesis results from the compromised cellulase gene transcription. Down-regulation of Trrab7 was also found to make T. reesei more sensitive to various stresses including carbon starvation. Interestingly, overexpression of Snf1, a serine/threonine protein kinase known as an energetic sensor, partially restored the cellulase production of Ptcu-rab7KD on Avicel, implicating that TrRab7 is involved in an energetic adaptation to carbon starvation which contributes to the successful cellulase gene expression when T. reesei is transferred from glucose to cellulose. TrRab7 was shown to play important roles in T. reesei development and a stress response to carbon starvation resulting from nutrient shift. This adaptation may allow T. reesei to successfully initiate the inducing process leading to efficient cellulase production. The present study provides useful insights into the functional involvement of the endosomal/vacuolar pathway in T. reesei development and hydrolytic enzyme production.

Amendments affect the community assembly and co-occurrence network of microorganisms in Cd and Pb tailings of the Eucalyptus camaldulensis rhizosphere

Mining tailings containing large amounts of Pb and Cd cause severe regional ecosystem pollution. Soil microorganisms play a regulatory role in the restoration of degraded ecosystems. The remediation of heavy metal-contaminated tailings with amendments and economically valuable Eucalyptus camaldulensis is a research hotspot due to its cost-effectiveness and sustainability. However, the succession and co-occurrence patterns of these microbial communities in this context remain unclear. Tailing samples of five kinds of Cd and Pb were collected in E. camaldulensis restoration models. Physicochemical properties, the proportions of different Cd and Pb forms, microbial community structure, and the co-occurrence network of rhizosphere tailings during different restoration process (organic bacterial manure, organic manure, inorganic fertilizer, bacterial agent) were considered. Organic and organic bacterial manures significantly increased pH, cation exchange capacity, and the proportion of residual Pb. Still, there was a significant decrease in the proportion of reducible Pb. The changes in microbial communities were related to physicochemical properties and the types of amendments. Organic and organic bacterium manures decreased the relative abundance of oligotrophic groups and increased the relative abundance of syntrophic groups. Inorganic fertilizers and bacterial agents decreased the relative abundance of saprophytic fungi. B. subtilis would play a better role in the environment improved by organic manure, increasing the relative abundance of beneficial microorganism and reducing the relative abundance of pathogenic microorganism. pH, cation exchange capacity, and the proportion of different forms of Pb were the main factors affecting the bacterial and fungi variation. All four amendments transformed the main critical groups of the microbial network structure from acidophilus and pathogenic microorganisms to beneficial microorganisms. Heavy metal-resistant microorganisms, stress-resistant microorganisms, beneficial microorganisms that promote nutrient cycling, and copiotrophic groups have become critical to building stable rhizosphere microbial communities. The topological properties and stability of the rhizosphere co-occurrence network were also enhanced. Adding organic and organic bacterium manures combined with E. camaldulensis to repair Cd and Pb tailings improved (1) pH and cation exchange capacity, (2) reduced the biological toxicity of Pb, (3) enhanced the stability of microbial networks, and (4) improved ecological network relationships. These positive changes are conducive to the restoration of the ecological functions of tailings.

Nitrogen addition changed soil fungal community structure and increased the biomass of functional fungi in Korean pine plantations in temperate northeast China

Nitrogen (N) deposition is a global environmental issue that can have significant impacts on the community structure and function in ecosystems. Fungi play a key role in soil biogeochemical cycles and their community structures are tightly linked to the health and productivity of forest ecosystems. Based on high-throughput sequencing and ergosterol extraction, we examined the changes in community structure, composition, and biomass of soil ectomycorrhizal (ECM) and saprophytic (SAP) fungi in 0–10 cm soil layer after 8 years of continuous N addition and their driving factors in a temperate Korean pine plantation in northeast China. Our results showed that N addition increased fungal community richness, with the highest richness and Chao1 index under the low N treatment (LN: 20 kg N ha−1 yr−1). Based on the FUN Guild database, we found that the relative abundance of ECM and SAP fungi increased first and then decreased with increasing N deposition concentration. The molecular ecological network analysis showed that the interaction between ECM and SAP fungi was enhanced by N addition, and the interaction was mainly positive in the ECM fungal network. N addition increased fungal biomass, and the total fungal biomass (TFB) was the highest under the MN treatment (6.05 ± 0.3 mg g−1).Overall, we concluded that N addition changed soil biochemical parameters, increased fungal activity, and enhanced functional fungal interactions in the Korean pine plantation over an 8-year simulated N addition. We need to consider the effects of complex soil conditions on soil fungi and emphasize the importance of regulating soil fungal community structure and biomass for managing forest ecosystems. These findings could deepen our understanding of the effects of increased N deposition on soil fungi in temperate forests in northern China, which can provide the theoretical basis for reducing the effects of increased N deposition on forest soil.

HacA, a key transcription factor for the unfolded protein response, is required for fungal development, aflatoxin biosynthesis and pathogenicity of Aspergillus flavus

Aspergillus flavus is a fungus notorious for contaminating food and feed with aflatoxins. As a saprophytic fungus, it secretes large amounts of enzymes to access nutrients, making endoplasmic reticulum (ER) homeostasis important for protein folding and secretion. The role of HacA, a key transcription factor in the unfolded protein response pathway, remains poorly understood in A. flavus. In this study, the hacA gene in A. flavus was knockout. Results showed that the absence of hacA led to a decreased pathogenicity of the strain, as it failed to colonize intact maize kernels. This may be due to retarded vegetable growth, especially the abnormal development of swollen tips and shorter hyphal septa. Deletion of hacA also hindered conidiogenesis and sclerotial development. Notably, the mutant strain failed to produce aflatoxin B1. Moreover, compared to the wild type, the mutant strain showed increased sensitivity to ER stress inducer such as Dithiothreitol (DTT), and heat stress. It also displayed heightened sensitivity to other environmental stresses, including cell wall, osmotic, and pH stresses. Further transcriptomic analysis revealed the involvement of the hacA in numerous biological processes, including filamentous growth, asexual reproduction, mycotoxin biosynthetic process, signal transduction, budding cell apical bud growth, invasive filamentous growth, response to stimulus, and so on. Taken together, HacA plays a vital role in fungal development, pathogenicity and aflatoxins biosynthesis. This highlights the potential of targeting hacA as a novel approach for early prevention of A. flavus contamination.

Changes and driving factors of microbial community composition and functional groups during the decomposition of Pinus massoniana deadwood.

Clarifying changes in the microbial community in deadwood at different stages of decomposition is crucial for comprehending the role of deadwood in the biogeochemical processes and the sustainability of forest development. However, there have been no reports on the dynamics of microbial community during the decomposition of Pinus massoniana. We used the "space-for-time" substitution to analyze the characteristics of microbial community changes and the key influencing factors in the P. massoniana deadwood during different decomposition stages by 16S and ITS rRNA gene sequencing. The results suggest that the microbial community structure of the early decomposition (decay class I) was significantly different from the other decay classes, while the diversity and richness of the microbial community were the highest in the late decomposition (decay class V). The Linear Discriminant Analysis Effect Size analysis revealed that most bacterial and fungal taxa were significantly enriched in decay classes I and V deadwood. During the initial stages of decomposition, the relative abundance of the bacterial functional group responsible for carbohydrate metabolism was greater than the later stages. As decomposition progressed, the relative abundance of saprophytic fungi gradually decreased, and there was a shift in the comparative abundance of mixed saprophytic-symbiotic fungi from low to high before eventually decreasing. Total organic carbon, total nitrogen, carbon-to-nitrogen ratio, total potassium, total phenol, condensed tannin, lignin, and cellulose were significantly correlated with microbial community structure, with the carbon-to-nitrogen ratio having the greatest effect. Our results indicate that the physicochemical properties of deadwood, microbial community structural composition and functional group changes were related to the decay class, among which the carbon-to-nitrogen ratio may be an important factor affecting the composition and diversity of microbial communities.

Onychomycosis Caused by Aspergillus in a Patient with Leprosy: A Case Report

Aspergillus spp., one of the most common nondermatophyte molds (NDMs) that cause onychomycosis, are saprophytic fungi that can act as zoonotic agents and cause various health issues, including onychomycosis, in humans. Predisposing factors for onychomycosis include nail trauma, immunosuppression, and occupation. Nails in patients with leprosy are prone to change and develop onychomycosis due to unrecognized trauma to the nail area. Here, we report the case of a 25-year-old woman with 2-month history of white patches in fingernails and toenails, which were also brittle and damaged. She was a veterinarian who had frequent, direct interaction with animals, particularly dogs and cats. She denied trauma prior to the manifestation of symptoms and was undergoing leprosy treatment, including corticosteroids for leprosy reactions. Examination with potassium hydroxide revealed hyphae, and the nail culture revealed growth of fungal colonies with the characteristics of A. flavus. She received four cycles of itraconazole at 400 mg/day. Two of the three afflicted nails showed complete cure, whereas one nail showed mycologic cure. A. flavus is frequently found in animals, including dogs and cats and might have been a source of Aspergillus transmission, suggesting the patient's occupation and immunosuppression as risk factors for onychomycosis. Onychomycosis due to Aspergillus, particularly A. flavus, responds well to itraconazole pulse monotherapy.

A Case of Deep Cutaneous Mycosis Caused by Purpureocillium lilacinum

Purpureocillium lilacinum, previously known as Paecilomyces lilacinus, is a saprophytic fungus typically found in soil and decaying vegetation. Although it is infrequently pathogenic to humans, recent reports of P. lilacinum infections, primarily affecting the skin and eyes, have shown an increase. This report details a cutaneous infection caused by P. lilacinum in an 89-year-old woman. She presented with a 3-month history of an erythematous patch and nodule on her right forearm. A skin biopsy revealed inflammation, granuloma, and fungal organisms in the dermis. Periodic acid-Schiff (PAS) staining confirmed the presence of fungal elements. The fungal culture of the medium produced colonies with a velvety pink and brown hue. PCR testing on these cultured samples identified P. lilacinum. The patient received a 2-week course of oral itraconazole (200 mg/day), which improved her symptoms. However, ongoing antifungal treatment was necessary. Additionally, due to a recent myocardiac infarction, the patient required a statin. A MIC test was conducted to identify an antifungal drug compatible with statin therapy.

Ancient prairies as a reference for soil organic carbon content and microbial community structure

The historic remnant prairies of Missouri display diversity above and below the soil surface and represent the few remaining acres of unconverted grassland habitat in the state. The soil microbiome is foundational to nutrient acquisition, resource partitioning, and ecosystem resilience; therefore, the intact plant-soil interactions of remnant prairies can serve as a reference for microbial community structure and ecosystem services lost due to land conversion. This research was conducted to show the importance of reference soil conditions and the variability that lies therein while contrasting degraded soil ecosystems to provide a standard to which comparable soils should be held. In this study, 35 sites across Missouri representing three prairie management conditions on similar soils and variable climatic conditions were compared to assess differences in the microbial community structure and biomass using phospholipid fatty acid (PLFA) analysis. Surface (0–7.5 cm) soil organic carbon (SOC) content provided a measure of substrate available to support microbial community health. Total microbial biomass, the biomass of individual microbial groups, selected biomarker ratios, and SOC, were significantly different across treatments and highest in remnant prairies apart from Saprophytic fungi and eukaryotes. This study demonstrated that the soil microbial community in reconstructed and restored prairie systems remained significantly diminished in biomass relative to remnant prairies, even after several decades. This study highlights the need to preserve remnant prairies, where soil is in its native state under native flora and abiotic conditions. These results also illustrate the importance of selecting remnant systems as the ecological reference standard for prairie lands.

Differences in soil fungal communities under salinity gradients in arid and semiarid regions

Salinization is considered a significant threat to soil ecosystem and plant growth in arid and semiarid regions. Soil microorganisms are supposed to be essential in relieving soil salinization and enhancing plant salt tolerance. However, although the responses of soil fungal diversity and community structure to salt stress have been investigated, major knowledge gaps remain in the interactions and community assembly of abundant and rare fungal taxa, and fungal functional characteristics under different salt intensities. Here, next-generation sequencing technology were used to investigate the response of all, abundant and rare fungal taxa to salt stress in arid and semiarid regions. The results demonstrated that high salt stress reduced the complexity and stability of fungal networks and increased fungal collaborations. Rare taxa held a key position in the co-occurrence network and exhibited greater proficiency in collaborating with intermediate and rare taxa, thereby augmenting the resistance of the community and maintaining its stability. Notably, with increasing salt stress, the importance of rare taxa gradually enhanced, while the importance of abundant taxa decreased. Moreover, fungal communities were manipulated by stochastic processes under salt stress, while were also influenced by deterministic processes (heterogeneous selection), especially for rare taxa. Furthermore, low salinity conditions promoted the colonization of saprophytic and symbiotic fungi and inhibited the growth of pathogenic fungi. Functional groups associated with fungal parasite-soil saprotroph-undefined saprotroph function were extremely sensitive to soil salinity and exerted a pivotal influence in sustaining community stability. Our findings may broaden our understanding of how abundant and rare fungi react to salt stress, making it easier to forecast the possible loss of biodiversity due to soil salinization, and offering microbial references for the development of saline-alkaline soil.

Responses of vascular plant fine roots and associated microbial communities to whole-ecosystem warming and elevated CO2 in northern peatlands.

Warming and elevated CO2 (eCO2) are expected to facilitate vascular plant encroachment in peatlands. The rhizosphere, where microbial activity is fueled by root turnover and exudates, plays a crucial role in biogeochemical cycling, and will likely at least partially dictate the response of the belowground carbon cycle to climate changes. We leveraged the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment, to explore the effects of a whole-ecosystem warming gradient (+0°C to 9°C) and eCO2 on vascular plant fine roots and their associated microbes. We combined trait-based approaches with the profiling of fungal and prokaryote communities in plant roots and rhizospheres, through amplicon sequencing. Warming promoted self-reliance for resource uptake in trees and shrubs, while saprophytic fungi and putative chemoorganoheterotrophic bacteria utilizing plant-derived carbon substrates were favored in the root zone. Conversely, eCO2 promoted associations between trees and ectomycorrhizal fungi. Trees mostly associated with short-distance exploration-type fungi that preferentially use labile soil N. Additionally, eCO2 decreased the relative abundance of saprotrophs in tree roots. Our results indicate that plant fine-root trait variation is a crucial mechanism through which vascular plants in peatlands respond to climate change via their influence on microbial communities that regulate biogeochemical cycles.

Dynamic changes in fungal communities and functions in different air-curing stages of cigar tobacco leaves.

Air curing (AC) plays a crucial role in cigar tobacco leaf production. The AC environment is relatively mild, contributing to a diverse microbiome. Fungi are important components of the tobacco and environmental microbiota. However, our understanding of the composition and function of fungal communities in AC remains limited. In this study, changes in the chemical constituents and fungal community composition of cigar tobacco leaves during AC were evaluated using flow analysis and high-throughput sequencing. The moisture, water-soluble sugar, starch, total nitrogen, and protein contents of tobacco leaves exhibited decreasing trends, whereas nicotine showed an initial increase, followed by a decline. As determined by high-throughput sequencing, fungal taxa differed among all stages of AC. Functional prediction showed that saprophytic fungi were the most prevalent type during the AC process and that the chemical composition of tobacco leaves is significantly correlated with saprophytic fungi. This study provides a deeper understanding of the dynamic changes in fungal communities during the AC process in cigar tobacco leaves and offers theoretical guidance for the application of microorganisms during the AC process.

Responses of soil bacterial and fungal community structure and functions to different plant species in a mixed forest plantation in a semi-arid region of China

Soil microbial communities play important roles in biogeochemical cycles and ecosystem functioning. However, how tree and grass species affect soil microbial structure and functions in semi-arid regions is poorly understood. In this study, we used sequencing of representative genes and bioinformatic analysis to compare the soil bacterial and fungal communities and their functional groups among legume and non-legume broad-leaved plantations, conifer plantations, artificial grassland, and adjacent farmland in a semi-arid area of Northern China. We found that soil bacterial diversity and abundance were significantly increased by legume plantations, especially Robinia pseudoacacia, compared to farmland. Soil bacterial communities were dominated by K-strategists in plantation soils and by r-strategists in farmland and grassland soils. Soil fungal communities showed contrasting patterns between Ascomycetes and Basidiomycota across treatments, and the highest abundance of nutrient indicator taxa Mortierellomycota was observed in plantation soils. Functional analysis revealed that afforestation altered the capacity of soil bacteria for organic compound mineralization and C and N cycling, and that different plant species enriched different types of ectomycorrhizal and saprophytic fungi. Moreover, we found that plantations and grasslands formed more connected but less complex and stable bacterial co-occurrence networks than farmland, and that conifer plantations increased the closeness of soil fungal networks compared to broad-leaved plantations. Our results suggest that tree and grass species play a key role in shaping the soil microbial community structure and functional groups, and provide valuable information for choosing suitable tree and grass species for ecosystem restoration and management in semi-arid regions.