Fungal Species Composition Research Articles

Sustainable Protection of Roses Grown in Foil Tunnels Using Biological Preparations

Recently, the ecological awareness of society and the need to take care of the natural environment have increased significantly. There is also an urgent problem of searching for new, environmentally friendly, and safe for people plant protection techniques using biological preparations, which reduce the intensive and cause significant health problems chemical protection. The study was conducted in a foil tunnel on the ‘Red House’ cultivar roses grown using an adapted method with shoot bending. Maintaining their health under tunnel conditions is often problematic. The study determined the effect of biopreparations on plant health (disease index), photosynthesis parameters, and gas exchange, as well as the species composition of fungi inhabiting roses. The preparations used did not negatively affect the process of photosynthesis and gas exchange. Among the 25 species of fungi obtained from its organs, the polyphagous species Botrytis cinerea dominated; the organs were very often colonized by fungi from the genera Fusarium, Phoma, and Alternaria alternata. The highest concentration of the Biosept 33 SL biopreparation shows a protective effect similar to that of the preparations used in chemical protection, and the degree of leaf blade infection shows a similar level.

Mycelium biomass and community composition impact nutrient concentration in arbuscular mycorrhizal fungi at fine spatial scale

Abstract The dynamic exchange of carbon (C) and nutrients between arbuscular mycorrhizal (AM) fungi and their host plants is crucial for shaping the spatial heterogeneity of nutrients within the hyphal network. This exchange is influenced not only by mycelial growth and its interactions with plants but also by the variability of soil nutrients. Despite its importance, the spatial heterogeneity of nutrients within the mycelial network and the factors driving this variability remain poorly understood. In the field of plant–AM fungi interactions, many studies have predominantly concentrated on large‐scale spatial patterns, disregarding the heterogeneity at fine scales and potentially missing vital insights into nutrient exchange between plants and AM fungi. We conducted an experiment to quantify the spatial heterogeneity of plant–soil–mycelia nutrients within a gridded 2 × 2 m2 quadrat. Hyphal in‐growth bags were installed to extract pure AM mycelium. The concentrations of C ([C]), nitrogen ([N]), and phosphorus ([P]) in both plant and mycelium tissues were measured. Additionally, the AM fungal community from the extracted hyphae was sequenced to assess AM fungal composition. Mycelium [N] and [P] at fine scales ranged from 2.18% to 3.37% and 0.99% to 4.46%, respectively, and their variations were much higher than those in shoot and root tissues. Mycelium stored significant amounts of nutrients, particularly [P] (2.27% in average), with levels exceeding those found in plant tissue by over 20‐fold. Mycelium [C] or [N] concentration was negatively correlated, while mycelium [P] was positively correlated with mycelium biomass. This suggests that the primary driving factor behind the variability in mycelium nutrients is mycelium biomass, which is somewhat influenced by AM fungal species composition. Investigating the variability of mycelium nutrients at fine scales enhances our understanding of nutrient cycling within ecosystems. This research also highlights the importance of studying the functional traits of AM fungi and introduces the concept that mycelium could serve as underground P reservoirs. Read the free Plain Language Summary for this article on the Journal blog.

The complex of phytopathogens of winter wheat grain in the conditions of the forest-steppe zone of the Central Caucasus

The results of studies of the species composition of fungi of the genus Fusarium in winter wheat grain obtained in the conditions of the forest-steppe zone of the Central Caucasus are presented. Phylogenetic analysis methods, based on the polymorphism of ?-tubulin genes, revealed 14 species of fungi of the genus Fusarium from diseased wheat grain with signs of fusarium. The dominant species is F. graminearum, with a frequency of occurrence of more than 40%. The species F. avenaceum, F. sporotrichioides and F. equiseti were also noted with high frequency. For the first time, for the forest-steppe zone of the Central Caucasus, the following species were found in winter wheat grain: F. boothii, F. vorosii, F. sporotrichioides, F. oxysporum, F. incarnatum, F. proliferatum. The results obtained indicate a community of fusarium fungi that are constantly present in the grain agrocenosis. The constant presence of a complex of fusarium fungi in the agrocenosis, occupying various ecological niches, ensures continuous infection of the ear and grain, starting from the flowering phase to harvesting.

Study of endophytic fungi of Ipomoea pes-caprae reveals the superiority of in situ plant conservation over ex situ conservation from a mycological view

In nature conservation, ex situ and in situ conservation strategies are discussed for protecting endangered species of plants and animals. However, the impacts of these strategies on the microbes associated with these species are rarely considered. In our study, we chose the endophytic fungi of the pantropical creeping plant Ipomoea pes-caprae as representative coastal plant in two natural coastal populations and two botanical gardens in Taiwan as collection sites in order to investigate the potential effect of ex situ plantation on the biodiversity of microbes intimately associated with this plant. In a culture-dependent approach, endophytic fungi were isolated under axenic conditions and identified to species, genus, or higher taxonomic ranks with DNA barcodes and morphology. In addition to yielding ca. 800 strains and over 100 morphospecies, a principal component analysis (PCA) of the distribution of the dominant fungal species showed clear differences in the composition of endophytic fungal species depending on the sampling sites. We conclude that the endophytic fungi from the original site are replaced by other species in the ex situ plantations. Due to the limitations of ex situ conservation of microbes and from a mycological and microbial perspective, in situ conservation should outweigh ex situ approaches.

A comprehensive analysis of Ardisia crenata Sims from endophytes and rhizosphere soil microorganisms.

Endophytic and rhizosphere microorganisms play crucial roles in influencing the quality and secondary metabolite accumulation of traditional Chinese medicinal. Endophytic and rhizosphere microorganisms play crucial roles in influencing the quality and secondary metabolite accumulation of traditional Chinese medicinal. A total of 8,514,557 highquality reads were generated from 140 plant and soil sample in A. crenata Sims based on high-throughput sequencing. The fungal species composition within the endophytic and rhizosphere soil samples of A. crenata Sims is rich and varied, exhibiting notable disparities across different geographical regions of the plant. The alpha diversity and beta diversity indicated significant differences in microbial diversity and community structure between soil and plants. As for endophytic fungi, the dominant phyla in both plants and soil were Ascomycota and Basidiomycota, with different dominant genera between the two compartments. LEfSe analysis at the genus level identified 80 and 124 fungal indicator taxa associated with plants and soil, respectively, including Aspergillus, Acremonium, Fusarium, among others. Co-occurrence network analysis demonstrated intimate interactions among soil fungal microorganisms. Examination of soil physicochemical factors and the primary active constituent (bergenin) across different regions of A. crenata Sims indicated that the highest bergenin concentration is found in the Guangxi region, whereas the Guizhou region boasts relatively abundant soil nutrient components. Correlation analysis revealed that Aspergillus, Fusarium, Penicillium, Tausonia, and Trichoderma are correlated with soil physicochemistry or active compounds. These findings hint at a potential role for endophytic and rhizosphere microorganisms in the accumulation of active compounds within medicinal plants, thereby furnishing a scientific rationale for guiding the cultivation practices of A. crenata Sims.

The Microfungal Communities in Deep-Sea Sediments from the Equatorial Atlantic

Microfungi of deep-sea sediments, and especially those several meters below the water–sediment interface, are poorly studied. In this work, for the first time, microfungal communities isolated by cultivation from deep-sea sediments of the eastern part of the Equatorial Atlantic (the Romanche and Chain Fracture Zones) were investigated. Fungi were isolated from sediments sampled at each of 12 stations from horizons 1.0–4.7 m below the sediment–water interface. To study microscopic fungi, one sediment horizon was isolated from each core. The fungal abundances were within the range of 0.0–3300.0 CFU g-1 sediment dry weight. A total of 19 fungal taxa from the phyla Ascomycota (18) and Basidiomycota (1) were identified, and Mycelia sterilia 1 strain was also isolated. Seven fungal species were encountered only once. In this case, the maximum similarity of species composition, in terms of the Bray – Curtis coefficient, was 57.14% (horizons 1.0 and 3.6 m, four common species). A comparison of the taxonomic structures of fungal communities from the study area was made with those from sediments of the Indian and Pacific Oceans and other areas of the Atlantic. The fungal communities from sediments in the study area were compared with those from the Indian and Pacific Oceans and other areas of the Atlantic. From the literature data and present study results, a list of fungal species with 180 names was compiled. The fungi belonged to 97 genera, 57 families, 32 orders and 13 classes of the phyla Ascomycota, Basidiomycota, and Mucoromycota. The diversity of fungal communities was assessed using indicators of taxonomic richness (number of taxa from different ranks), proportions (genera/families, species/families, species/genera), Average Taxonomic Distinctness index (AvTD, Δ+) and Variation in Taxonomic Distinctness index (VarTD, Λ+). Four and twelve fungal classes were identified in sediments in the Eastern Equatorial Atlantic and the Indian Ocean, respectively. The species/genera proportions in the communities varied from 1.33 (Indian Ocean) to 3.8 (other areas of the Atlantic Ocean). For the fungal communities of the Eastern Equatorial Atlantic, the AvTD index value was minimal (Δ+ = 50.19), the VarTD index was maximal (Λ+ = 945.38), and they were beyond the 95% confidence interval. This was due to the small number of the fungal classes and vertical and horizontal unevenness of species distribution along taxonomic branches, which was manifested in the dominance of species of the family Aspergillaceae (78.9% of the species in the class Saccharomycetes and Eurotiomycetes), only two species belonging to the classes Sordariomycetes and one species belonging to the class Microbotryomycetes (phylum Basidiomycota). Consequently, statistically significant differences were found between the taxonomic structures of the fungal communities of the Eastern Equatorial Atlantic and the other regions of the World Ocean, which are due to the insufficient amount of data obtained on the species composition of fungi in the sediments of this area. The study did not reveal any pattern in the change in the number of fungal species and their abundance in relation to the water characteristics (temperature, pH, and salinity), horizon depth in the sediment core, sediment type, or sampling station location in the Romanche and Chain Fracture Zones.

Xylotrophic Agaricomycetes Monitoring in Some Types of Spruce and Birch Forests (Subzone of the Southern Taiga, Perm Territory, Russia)

We have summarized the results of xylotrophic agaricoid basidiomycetes long-term monitoring in some types of indigenous and derived forests in the southern taiga subzone of Perm Krai. We carried out the research by a stationary method on the test 50×20 m areas, one in each type of forest: spruce forest at the brook, sorrel spruce forest and birch forest. We did the work in three periods: I – 1975–1977, II – 1994–1996, III – 2010–2012. The collection of material was carried out annually: in August 3 times with an interval of 10 days (the species composition, number and air-dry biomass of basidiomes were taken into account), and in September once (only the species composition of fungi was taken into account). To date, we have established that the number of xylotrophic agaricoid fungi in the studied forest types varies from 60 (sorrel spruce forest) to 66 (birch forest). Most of the identified species belong to the Tricholomataceae family (37.7–43.3% of the total number of xylotrophic fungi species in each of the biogeocoenoses). There was an annual accumulation of detectable fungal species, with the largest number of species (67–75%) detected from 2 to 9 times, and 2–3% of them were permanent, occurring annually. There was relative stability of the species composition of higher vascular plants (Jaccard generality coefficient: J = 56–88) over time and more significant changes in the species composition of xylotrophic fungi (J = 36–50). The spruce forests had the most similarity of fungi species composition between the cenoses by periods (J = 44–52), and for the entire observation period, the sorrel spruce forest and birch forest had the maximum Jaccard index between cenoses (J = 56). The yield of xylotrophic agaricoid fungi in the studied cenoses varies by years of observation. The birch forest had the largest number and biomass of basidiomata for all the three periods of the research. A decrease in the number of basidiomes of xylotrophic fungi in the sorrel spruce forest was established with an increase in the average monthly air temperature in August (Spearman correlation coefficient: rs = −0.70). The sorrel spruce forest was the most favorable for the biota of xylotrophic agaricoid basidiomycetes, both in number (Shannon index: H = 1.23) and in biomass (H = 1.20), during all the research, since the biota of xylotrophes of the specified cenosis was more diverse and its components were most aligned.

Eucalyptus and Native Broadleaf Mixed Cultures Boost Soil Multifunctionality by Regulating Soil Fertility and Fungal Community Dynamics.

The growing recognition of mixed Eucalyptus and native broadleaf plantations as a means of offsetting the detrimental impacts of pure Eucalyptus plantations on soil fertility and the wider ecological environment is accompanied by a clear and undeniable positive impact on forest ecosystem functions. Nevertheless, the question of how mixed Eucalyptus and native broadleaf plantations enhance soil multifunctionality (SMF) and the mechanisms driving soil fungal communities remains unanswered. In this study, three types of mixed Eucalyptus and native broadleaf plantations were selected and compared with neighboring evergreen broadleaf forests and pure Eucalyptus plantations. SMF was quantified using 20 parameters related to soil nutrient cycling. Partial least squares path modeling (PLS-PM) was employed to identify the key drivers regulating SMF. The findings of this study indicate that mixed Eucalyptus and native broadleaf plantations significantly enhance SMF. Mixed Eucalyptus and native broadleaf plantations led to improvements in soil properties (7.60-52.22%), enzyme activities (10.13-275.51%), and fungal community diversity (1.54-29.5%) to varying degrees compared with pure Eucalyptus plantations. Additionally, the mixed plantations exhibit enhanced connectivity and complexity in fungal co-occurrence networks. The PLS-PM results reveal that soil properties, fungal diversity, and co-occurrence network complexity directly and positively drive changes in SMF. Furthermore, soil properties exert an indirect influence on SMF through their impact on fungal diversity, species composition, and network complexity. The findings of this study highlight the significant role of mixed Eucalyptus and native broadleaf plantations in enhancing SMF through improved soil properties, fungal diversity, and co-occurrence network complexity. This indicates that incorporating native broadleaf species into Eucalyptus plantations can effectively mitigate the negative impacts of monoculture plantations on soil health and ecosystem functionality. In conclusion, our study contributes to the understanding of how mixed plantations influence SMF, offering new insights into the optimization of forest management and ecological restoration strategies in artificial forest ecosystems.

New Data on Fungal Species Composition in Spruce Trunk Canker.

The composition of canker mycobiota on spruce trunks was studied in the Lisinsky forestry (Leningrad Oblast). Small cankers or canker parts were placed in a humid chamber. Fungi were identified by morphological features. Sorocybe resinae (Fr.) Fr. and Penicillium glaucoalbidum (Desm.) Houbraken & Samson were the most common. The S. resinae occurrence was 75.9 ± 7.9%. The fungus developed in the surface layers of dried resin, but was not detected in the absence of resin production. The fungus S. resinae was therefore assumed to be a nearly ubiquitous component of the mycobiota of resinous cankers on spruce trunks in Leningrad Oblast. The fungus P. glaucoalbidum has only been observed as a saprotroph in Russia earlier. Weak pathogenic properties were detected in the species in experiments; i.e., P. glaucoalbidum grew on live bark tissues in a humid chamber. Based on its high occurrence (41.4 ± 9.1%), P. glaucoalbidum was identified as a regular component of the microbiota in spruce necrotic canker. Pure cultures of P. glaucoalbidum and Oidiodendron sp. were obtained. To test the respective species as possible causative agents of trunk canker, trunks of 20spruce trees were inoculated with the fungal cultures in a forest stand. The cultures stimulated resin secretion without causing necrosis to spread beyond the inflicted wound. To better understand the phenomenon, a more detailed study of the biota in necrotic cankers is necessary to perform with a special focus on their nonpathogenic part, which has not received proper attention as of yet.

Comparative microbiome diversity in root-nodules of three Desmodium species used in push-pull cropping system.

Desmodium species used as intercrops in push-pull cropping systems are known to repel insect-pests, suppress Striga species weeds, and shift soil microbiome. However, the mechanisms through which Desmodium species impact the soil microbiome, either through its root exudates, changes in soil nutrition, or shading microbes from its nodules into the rhizosphere, are less understood. Here, we investigated the diversity of root-nodule microbial communities of three Desmodium species- Desmodium uncinatum (SLD), Desmodium intortum (GLD), and Desmodium incanum (AID) which are currently used in smallholder maize push-pull technology (PPT). Desmodium species root-nodule samples were collected from selected smallholder farms in western Kenya, and genomic DNA was extracted from the root-nodules. The amplicons underwent paired-end Illumina sequencing to assess bacterial and fungal populations. We found no significant differences in composition and relative abundance of bacterial and fungal species within the root-nodules of the three Desmodium species. While a more pronounced shift was observed for fungal community compositions compared to bacteria, no significant differences were observed in the general diversity (evenness and richness) of fungal and bacterial populations among the three Desmodium species. Similarly, beta diversity was not significantly different among the three Desmodium species. The root-nodule microbiome of the three Desmodium species was dominated by Bradyrhizobium and Fusarium species. Nevertheless, there were significant differences in the proportion of marker gene sequences responsible for energy and amino acid biosynthesis among the three Desmodium species, with higher sequence proportions observed in SLD. There is no significant difference in the microbial community of the three Desmodium species used in PPT. However, root-nodule microbiome of SLD had significantly higher marker gene sequences responsible for energy and amino acid biosynthesis. Therefore, it is likely that the root-nodules of the three Desmodium species host similar microbiomes and influence soil health, consequently impacting plant growth and agroecosystem functioning.

Analysis of Basidiomycete Fungal Communities in Soil and Wood from Contrasting Zones of the AWPA Biodeterioration Hazard Map across the United States

Wood deterioration due to basidiomycetous decay fungi shortens the useful life span of wood and wood-based materials. Prescriptive preservative treatment is the most effective way to reduce the detrimental effects of these microorganisms, particularly in soil contact and areas of critical use (difficult to replace or vital to structure). Current American Wood Protection Association (AWPA) guidelines in the standardized use category system specify 3 zones of severity regarding wood decay fungal hazards but contain very little information on the diversity and abundance of these fungi colonizing soil and wood. In this study, amplicon based sequencing was utilized to compare fungal communities in wood and adjacent soil to provide baseline data on the fungi involved in the process. A thorough understanding of decay hazards is critical for the proper selection and use of wood in soil contact. The goal of this work is to provide baseline data on basidiomycete fungal diversity and species composition in different zones of the existing 3-zone AWPA hazard map as compared to the previous 5-zone hazard map and Scheffer decay indices and discuss the ecological implications for wood decay.

Structure particularity of spring barley mycocenoses and properties of mushrooms from alienated radioactively contaminated territories of the Novozybkovsky district of the Bryansk region

The features of the structure of mycocenoses of spring barley Gonar in the alienated territories of the Novozybkovsky district of the Bryansk region, contaminated with radionuclides as a result of the Chernobyl accident, have been studied. The study was carried out in 1991–1998 (pollution density 137Cs ~1.8 MBq/m2) using traditional field methods of observation and laboratory analyses to identify fungal species and determine their activity. 7 years after the accident, the epiphytic microbiota of barley seeds was characterized by increased activity of fungi from the genus Fusarium with the dominance of the causative agent of snow mold F. nivale Ces. (Microdochium nivale) and the mycotoxic fungus F. sporotrichiella Bilai. (sin. F. sporotrichioides). For comparison, at the same time, the microbiota of barley seeds in the fields of the Ramenskoye district of the Moscow region differed not only in the species composition of fungi, but also in their properties: the absence of such species of fungi as Nigrospora oryzae and Ulocladium con-sortiala, quite numerous in the Bryansk fields, and the presence of micro-roorganisms of the fungus F. sambucinum Fuckel, not found on polluted 137Cs and fields removed from economic turnover. There is also a noticeable presence of fungi from the genus Fusarium in the structure of the intra-seed infection of barley. The properties of metabolites of fungi from the genus Penicillium were determined: suspensions of fungal spores P. expansum and P. cyclopium used for processing barley seeds caused depression – a significant decrease in seed germination and morphophysiological characteristics of the development of seedlings. Isolates of 26 species of fungi were screened for their effect on the survival of paramecia and their rating was compiled. It is shown that in the absence of planned management of crop production by regional technologies and the use of plant protection products against diseases for 7 years after the accident, there was a shift in the structure of fungal species present on the roots and stems of barley of the Gonar variety towards an increase in the proportion of phytopathogenic fungi. With a large number of micromycete species on barley plants on radionuclide-contaminated fields of the Bryansk region and “clean” lands of the Moscow region (22 species versus 21, respectively), 9 species of phytopathogens (41% of the total number of species) and 7 species (33%) were isolated in technogenic territories. At the same time, the total activity of phytopathogens in the alienated radioactively contaminated territories was 18 points, in the “clean” ones – 13. Ratio of Phytopathogens/Saprophytes, calculated by the total activity of these groups of fungi, in the Bryansk region was 37.5% more than in the Moscow region, and by the ratio of Phytopath-genes/Antagonists – 2.2 times more. At the same time, the tendency of phytopathogens to prevail over other types of fungi in radioactively contaminated areas was natural, which was confirmed by the results of earlier studies.

Conceptual basis for studying the fungal biodiversity in organogenic soils in the area of the Bulgarian Antarctic Base ‘St. Kliment Ohridski’ on Livingston Island

In 2023, a scientific project for studying the fungal biodiversity in organogenic soils in the area of the Bulgarian Antarctic Base ‘St. Kliment Ohridski’ on Livingston Island was funded by the National Center for the Polar Studies at Sofia University ‘St. Kliment Ohridski’, implemented under the National Program for Polar Research ‘From Pole to Pole’, adopted by the Ministry of Education and Science.  In the period February-March 2023, a total of 126 soil samples were collected for analysis. Soil samples were carried out in the upper 0-5 cm soil layer. In places with deeper soil profiles, samples were collected from the deeper layer >5 cm. All samples were stored in sterile polyethylene bags in a freezer at minus 28°C on the Bulgarian ship ‘St. St. Cyril and Methodius’, which arrived in Bulgaria on 2nd May 2023. The present study aims to present the conceptual basis for the study of structure, composition, and bioecological features of fungal species occurring in Antarctic organogenic soils from Livingston Island, to investigate the representatives of separate taxonomic groups of invertebrate organisms interacting with the fungal species in the soil, and to establish the relationships with the soil characteristics in the studied sites. Studies of the biological and ecological features of representatives of the mycota in Antarctic organogenic soils, their physiological and biochemical behavior, and interaction with invertebrate organisms, are essential for a better understanding of the biological processes occurring in them, and the implementation of this project will have substantial contribution to these issues.

Current state of the species composition of mycobiota in South-East Kazakhstan

To date, no information has been available on the species composition of fungi in southeastern Kazakhstan, the center of agrobiodiversity but also home to rare and endemic species. Therefore, our objective was to investigate the diversity of fungi, fungus-like organisms, and lichens in southeastern Kazakhstan. The scientific and practical significance of the work is to obtain data on the species composition of mycobiota, which will allow planning measures for its monitoring, protection and restoration. The material for the article served as the authors’ own collections, conducted in 2021-2023. The study and identification of fungi were carried out according to the standard methodology. In the study area 2864 species of fungi, fungus-like organisms and lichens from 3 kingdoms, 22 classes, 84 orders, 260 families and 770 genera were found. Among them, 36 species were new to southeastern Kazakhstan, and 8 species were new to Kazakhstan. It is worth noting that the Karasay region had the largest number of species (1547) when analyzing the distribution of fungi, fungus-like organisms, and lichens. The study’s value and practical significance lies in the data obtained on the species composition of fungi, fungus-like organisms, and lichens, including their distribution and confinement to different types of substrates.

Lesões labiais em cavalos: relato de caso

ABSTRACT The article presents the results of monitoring studies on the mucous membrane lesions in Trakehner horses. Based on clinical examination, the localization, size, and number of ulcers, as well as the inflammatory reaction to the presence of necrotic tissue, were determined. In addition to clinical examination, planimetric studies were also carried out to determine the size of the ulcers and the dynamics of their reduction during treatment with aerosol application of PVP iodine spray. To determine the nature of inflammation in the lesion focus, smears were taken from the surface of the ulcers. Microbiological and mycological studies of pathological tissues and feed samples were carried out to establish the etiological factors contributing to the ulcers. It was found that the size of the ulcers varied from 1 to 6 cm, and they were located on the upper and lower lips on both the right and left sides. Neutrophilic leukocytosis was observed in the focus of inflammation. Leukocytes actively phagocytized microorganisms present in the pathological focus. Microscopic fungi of the species A. flavus, A. fumigatus, M. species, and P. commune sprouted on Saburo medium from necrotic tissues of the pathological focus. A similar composition of fungal species was obtained by sowing feed samples fed to horses. Microbiological studies of ulcers revealed the growth of two microorganisms, S. aureus and P. vulgaris, on Baird-Parker agar. On the third day of treatment, compared to the first day, the size of the ulcers decreased by 22.8 %. It is recommended to perform primary surgical treatment of the ulcer, apply PVP iodine spray once a day, and replace the affected feed with high-quality feed to achieve a positive therapeutic effect.

Fungal communities in veteranised oak branches are not a replacement for naturally occurring dead wood communities

ABSTRACT Veteranisation is a promising management technique for dead wood creation at sites where dead wood, and ancient and veteran tree abundance is limited; it aims to replicate the microhabitats associated with ancient and veteran trees in younger trees by controlled physical damage of woody tissues. Five veteranisation treatments were applied, using a chainsaw, to healthy branches within the crowns of three mature oak trees. Treatments consisted of variations of cambium girdling, lopping, and lopping with girdling in combination; in addition, two branches that had died naturally were selected from each tree for comparison. Veteranised branches were harvested after 14 months. The fungal community composition was determined in different parts of the branch and their 3-dimensional structure mapped in representative branches. Stereum gausapatum was the most frequently isolated basidiomycete from veteranised branches, which occurred in all treatment types. The most commonly isolated ascomycete of veteranised branches was Ophiostoma quercus, which caused distinctive pockets of discoloured wood and was associated with half girdle treatments. There were significant differences in fungal species composition between veteranised branches and branches that had died naturally. This compositional difference may influence the development of later stage fungal communities, managers must consider these community compositional differences when prescribing veteranisation.

Rhizosphere microbial ecological characteristics of strawberry root rot.

Strawberry (Fragaria × ananassa Duch.) holds a preeminent position among small fruits globally due to its delectable fruits and significant economic value. However, strawberry cultivation is hampered by various plant diseases, hindering the sustainable development of the strawberry industry. The occurrence of plant diseases is closely linked to imbalance in rhizosphere microbial community structure. In the present study, a systematic analysis of the differences and correlations among non-culturable microorganisms, cultivable microbial communities, and soil nutrients in rhizosphere soil, root surface soil, and non-rhizosphere soil of healthy and diseased strawberry plants affected by root rot was conducted. The goal was to explore the relationship between strawberry root rot occurrence and rhizosphere microbial community structure. According to the results, strawberry root rot altered microbial community diversity, influenced fungal community composition in strawberry roots, reduced microbial interaction network stability, and enriched more endophytic-phytopathogenic bacteria and saprophytic bacteria. In addition, the number of bacteria isolated from the root surface soil of diseased plants was significantly higher than that of healthy plants. In summary, the diseased strawberry plants changed microbial community diversity, fungal species composition, and enriched functional microorganisms significantly, in addition to reshaping the microbial co-occurrence network. The results provide a theoretical basis for revealing the microecological mechanism of strawberry root rot and the ecological prevention and control of strawberry root rot from a microbial ecology perspective.

Summer Rice–Winter Potato Rotation Suppresses Various Soil-Borne Plant Fungal Pathogens

Growing potatoes (Solanum tuberosum) using the idle rice fields in Southern China and the Indo-Gangetic Plains of India in the winter season through the rice–potato rotation (RC) system could support future food security. However, the modulation capacity of the RC system on soilborne fungal pathogens is still unclear. In the current study, a pot experiment was designed and conducted to monitor the dynamics of soil fungal community composition between the potato monoculture (CC) system and the RC system, where the two systems were set with the same soil conditions: autoclaving with fertilization; autoclaving without fertilization; autoclave-free with fertilization; and autoclave-free without fertilization. Then, the uncultivated soil (CK) and root-zone soil samples of conditions under the two systems were collected, and then soil physiochemical properties and enzymatic activities were determined. Next, the high-variable region (V5–V7) of fungal 18S rRNA genes of the samples were amplified and sequenced through the PCR technique and the Illumina Miseq platform, respectively. Finally, the fungal species diversity and composition, as well as the relative abundance of fungal pathogens annotated against the Fungiuld database in soil samples, were also investigated. The results showed that the RC could significantly (p < 0.05) increase soil fungal species diversity and decrease the relative abundance of soil fungal pathogens, where the RC could suppress 23 soil fungal pathogens through cultivating the rice during the summer season and 93.75% of the remaining pathogens through winter-season cultivation. Seven-eighths of the conditions under RC have lower pathogenic MGIDI indices (6.38 to 7.82) than those of the CC (7.62 to 9.63). Notably, both rice cultivation and winter planting reduced the abundance of the pathogenic strain ASV24 under the Colletotrichum genus. The bipartite fungal network between the pathogens and the non-pathogens showed that the pathogenic members could be restricted through co-occurring with the non-pathogenic species and planting crops in the winter season. Finally, the redundancy analysis (RDA) indicated that soil pH, electronic conductivity, available phosphorus content, and various enzyme activities (cellulase, urease, sucrase, acid phosphatase, catalase, polyphenol oxidase) could be the indicators of soil fungal pathogens. This experiment demonstrated that the rice–potato rotation system outperformed the potato monoculture on suppressing soilborne fungal pathogenic community.

The bioaerosols generated from the sludge treatment process: Bacterial and fungal variation characteristics, source tracking, and risk assessment

The bioaerosols generated from the sludge treatment process: Bacterial and fungal variation characteristics, source tracking, and risk assessment

Fire shapes fungal guild diversity and composition through direct and indirect pathways.

Fire has shaped global ecosystems for millennia by directly killing organisms and indirectly altering habitats and resources. All terrestrial ecosystems, including fire-prone ecosystems, rely on soil-inhabiting fungi, where they play vital roles in ecological processes. Yet our understanding of how fire regimes influence soil fungi remains limited and our knowledge of these interactions in semiarid landscapes is virtually absent. We collected soil samples and vegetation measurements from sites across a gradient in time-since-fire ages (0-75 years-since-fire) and fire frequency (burnt 0-5 times during the recent 29-year period) in a semiarid heathland of south-eastern Australia. We characterized fungal communities using ITS amplicon-sequencing and assigned fungi taxonomically to trophic guilds. We used structural equation models to examine direct, indirect and total effects of time-since-fire and fire frequency on total fungal, ectomycorrhizal, saprotrophic and pathogenic richness. We used multivariate analyses to investigate how total fungal, ectomycorrhizal, saprotrophic and pathogenic species composition differed between post-fire successional stages and fire frequency classes. Time-since-fire was an important driver of saprotrophic richness; directly, saprotrophic richness increased with time-since-fire, and indirectly, saprotrophic richness declined with time-since-fire (resulting in a positive total effect), mediated through the impact of fire on substrates. Frequently burnt sites had lower numbers of saprotrophic and pathogenic species. Post-fire successional stages and fire frequency classes were characterized by distinct fungal communities, with large differences in ectomycorrhizal species composition. Understanding the complex responses of fungal communities to fire can be improved by exploring how the effects of fire flow through ecosystems. Diverse fire histories may be important for maintaining the functional diversity of fungi in semiarid regions.