Long-term Dynamics of Fungal Communities Inhabiting Decaying Stumps of Quercus robur.

We studied the diversity, composition, and long-term dynamics of wood-inhabiting fungi in Quercus robur stumps left after commercial tree harvesting in Lithuania. Sampling of wood was carried out at three sites and from stumps, which were 10-, 20-, 30-, 40-, and 50-year-old. DNA was isolated from wood samples and fungal communities analyzed using high-throughput sequencing. Results showed that stump age had a limited effect on fungal diversity. The development of fungal communities in oak stums was found to be a slow process as fungal communities remained similar for decades, while larger changes were only detected in older stumps. The most common fungi were Eupezizella sp. (18.4%), Hyphodontia pallidula (12.9%), Mycena galericulata (8.3%), and Lenzites betulinus (7.1%). Fistulina hepatica, which is a red-listed wood-decay oak fungus, was also detected at a low relative abundance in stump wood. In the shortage of suitable substrate, oak stumps may provide habitats for long-term survival of different fungal species, including red-listed and oak-related fungi.

Sheep dung deposition disrupted the soil microbiome in degraded grassland but not in non-degraded grassland.

Grazing is the most extensive land use in grassland worldwide, wherein the soil microbiome is known to support multiple ecosystem functions. Yet, the experimental impact of livestock grazing and dung deposits on the soil microbiome in degraded grassland remains poorly understood. We examined the effects of sheep dung depositions on the bacterial and fungal microbiome of two grasslands: non-degraded and degraded (long-term overgrazing) in northern China. Specifically, sheep dung was experimentally added to the soil and its effects on the soil microbial community were determined 3 months later (corresponding to livestock excreta deposited throughout the entire growing season of grassland, June to September). Our results showed that sheep dung additions showed negative effects on the soil microbiome of already degraded grassland, while with a diminished impact on the non-degraded grassland. In particular, dung deposition decreased soil microbial Shannon index, notably significantly reducing fungal diversity in degraded grassland. Moreover, sheep dung deposition modifies soil bacterial community structure and diminishes bacterial community network complexity. The alteration of soil pH caused by sheep dung deposition partially explains the decline in microbial diversity in degraded grassland. However, sheep dung did not alter the relative abundance and community composition of bacterial and fungal dominant phyla either in the non-degraded or in the degraded grassland. In conclusion, the short-term deposition of sheep dung exerted a detrimental influence on the microbial community in degraded grassland soil. It contributes new experimental evidence regarding the adverse effects of livestock grazing, particularly through dung deposition, on the soil microbiome in degraded grassland. This knowledge is crucial for guiding managers in conserving the soil microbiome in grazed grasslands.

Effects of polymerization types on plastics ingestion and biodegradation by Zophobas atratus larvae, and successions of both gut bacterial and fungal microbiomes.

Recent studies demonstrated that plastic degradation in Zophobas atratus superworms is related to the gut microbiota. To determine whether the biodegradation and gut-microbiota were influenced by ingested plastic polymerization types, foams of polypropylene (PP), polyurethane (PU) and ethylene vinyl acetate (EVA) were selected as representatives of polyolefins, polyester and copolymers, and the sole feedstock for superworms for 45 d. Both growth and survival rates of superworms were influenced by the type of plastic diet. Although the total consumptions of EVA- and PP-fed groups were similar at 29.03 ± 0.93 and 28.89 ± 1.14 mg/g-larva, which were both significantly higher than that of PU-fed groups (21.63 ± 2.18 mg/g-larva), the final survival rates of the EVA-fed group of 36.67 ± 10.41% exhibited significantly lower than that of the PP- and PU-fed groups of 76.67 ± 2.89% and 75.00 ± 7.07%, respectively, and even the starvation group of 51.67 ± 10.93%. The Illumina MiSeq results revealed similarities in the dominant gut bacterial communities between PU- and EVA-fed groups, with an increase in relative abundance of Lactococcus, but significant differences from the PP-fed groups, which had two predominant genera of unclassified Enterobacteriaceae and Enterococcus. Compared to bran-fed groups, changes in gut fungal communities were similar across all plastics-fed groups, with an increase in the dominant abundance of Rhodotorula. The abundance of Rhodotorula increased in the order of polyolefin, polyester, and copolymer. In summary, plastic ingestion, larval growth, and changes in gut bacterial and fungal community of superworms were all influenced by foam diets of different polymerization types, and especially influences on the gut microbiomes were different from each other.

Effects of slow-release nitrogen and urea combined application on soil physicochemical properties and fungal community under total straw returning condition.

Under the system of full straw returning, the relationship between soil fungal community diversity and soil physiochemical properties, and the combined application of slow-release nitrogen and urea is unclear. To evaluate its effect and provide an effective strategy for sustainable agricultural production, a 2-year field positioning trial was conducted using maize as the research object. The experiment was designed with two factors: straw treatment(S) and nitrogen fertilizer treatment(N),Six experimental treatments were set up,S1N0,S1N1,S1N2,S1N3,S1N4,S0N2,respectively.Analysis of 54 soil samples revealed 15 fungal phyla and 49 fungal classes. The composition of fungal communities in each treatment was basically the same, but there were significant differences in species abundance. Under total straw returning conditions, the combined application of slow-release nitrogen fertilizer and normal nitrogen fertilizer significantly increased the relative abundance of Ascomycota. During the jointing stage, tasseling stage and maturity stage, S1N4, S1N3 and S1N2 increased by 25.76%, 22.97%, 20.74%; 25.11%, 30.02%, 23.64% and 22.47%, 28.14%, 22.71% respectively compared with S0N2.The relative abundance of Basidiomycota was significantly reduced. Alpha diversity analysis showed that the straw returning mode significantly increased the Shannon index and decreased the Simpson index, which was obvious in the jointing stage and tasseling stage. The principal coordinate analysis analysis results showed that the fungal communities formed different clusters in the horizontal and vertical directions at the three growth stages of corn jointing, tasseling and maturity. At the jointing stage and tasseling stage, the communities of the straw return treatment and the straw removal treatment were separated, and the community distribution of each treatment was not significantly different in the mature stage. Total straw returning combined with slow-release fertilizer significantly (P＜0.05) increased the soil organic carbon, nitrate nitrogen and ammonia nitrogen content in each growth period, and increased the soil total nitrogen and hydrolyzable nitrogen content (P＞0.05).After the straw was returned to the field, the combined application of slow-release nitrogen fertilizer and common urea had a significant impact on soil urease, catalase, and sucrase activities. Among them, the three enzyme activities were the highest in the S1N3 treatment at the jointing stage and maturity stage, and the S1N4 treatment at the tasseling stage had the highest enzyme activity. Fungal community composition is closely related to environmental factors. Soil organic carbon, urease and catalase are positively correlated with Ascomycota and negatively correlated with Basidiomycota.

The characteristics of fungal responses to uranium mining activities and analysis of their tolerance to uranium.

The influence of uranium (U) mining on the fungal diversity (FD) and communities (FC) structure was investigated in this work. Our results revealed that soil FC richness and FD indicators obviously decreased due to U, such as Chao1, observed OTUs and Shannon index (P<0.05). Moreover, the abundances of Mortierella, Gibberella, and Tetracladium were notably reduced in soil samples owing to U mining activities (P<0.05). In contrast, the abundances of Cadophora, Pseudogymnoascus, Mucor, and Sporormiella increased in all soil samples after U mining (P<0.05). Furthermore, U mining not only dramatically influenced the Plant_Pathogen guild and Saprotroph and Pathotroph modes (P<0.05), but also induced the differentiation of soil FC and the enrichment of the Animal_Pathogen-Soil_Saprotroph and Endophyte guilds and Symbiotroph and Pathotroph Saprotroph trophic modes. In addition, various fungal populations and guilds were enriched to deal with the external stresses caused by U mining in different U mining areas and soil depths (P<0.05). Finally, nine U-tolerant fungi were isolated and identified with a minimum inhibitory concentration range of 400-600 mg/L, and their adsorption efficiency for U ranged from 11.6% to 37.9%. This study provides insights into the impact of U mining on soil fungal stability and the response of fungi to U mining activities, as well as aids in the screening of fungal strains that can be used to promote remediation of U mining sites on plateaus.

Performance of aerobic denitrifying fungal community for promoting nitrogen reduction and its application in drinking water reservoirs.

The effect of mix-cultured aerobic denitrifying microorganisms on the water remediation has been extensively explored, but little is known about the performance of mix-cultured low efficiency fungi on denitrification. In this study, two kinds of aerobic denitrifying fungi (Trichoderma afroharzianum H1 and Aspergillus niger C1) were isolated from reservoirs, improved the capacity by mix-cultured. The results showed a difference between northern and southern reservoirs, the dominants of genera were Cystobasidium and Acremonium. The removals of total nitrogen (TN) was 12.00%, 7.53% and 69.33% in Trichoderma afroharzianum H1, Aspergillus niger C1 and mix-cultured (C1 and H1) under the denitrification medium. The contents of ATP and electron transport system activity in mix-cultured amendment were increased by 42.54% and 67.52%, 1.72 and 2.91 times, respectively. Besides, the raw water experiment indicated that TN removals were 24.05%, 12.66% and 73.42% in Trichoderma afroharzianum H1, Aspergillus niger C1 and mix-cultured. The removals of dissolved organic carbon in mix-cultured were increased 35.02% and 50.46% compared to Trichoderma afroharzianum H1 and Aspergillus niger C1. Therefore, mix-cultured of two low efficiency aerobic denitrifying fungi has been considered as a novelty perspective for mitigation of drinking water source.

GlobalAMFungi: a global database of arbuscular mycorrhizal fungal occurrences from high-throughput sequencing metabarcoding studies.

Arbuscular mycorrhizal (AM) fungi are crucial mutualistic symbionts of the majority of plant species, with essential roles in plant nutrient uptake and stress mitigation. The importance of AM fungi in ecosystems contrasts with our limited understanding of the patterns of AM fungal biogeography and the environmental factors that drive those patterns. This article presents a release of a newly developed global AM fungal dataset (GlobalAMFungi database, https://globalamfungi.com) that aims to reduce this knowledge gap. It contains almost 50 million observations of Glomeromycotinian AM fungal amplicon DNA sequences across almost 8500 samples with geographical locations and additional metadata obtained from 100 original studies. The GlobalAMFungi database is built on sequencing data originating from AM fungal taxon barcoding regions in: i) the small subunit rRNA (SSU) gene; ii) the internal transcribed spacer 2 (ITS2) region; and iii) the large subunit rRNA (LSU) gene. The GlobalAMFungi database is an open source and open access initiative that compiles the most comprehensive atlas of AM fungal distribution. It is designed as a permanent effort that will be continuously updated by its creators and through the collaboration of the scientific community. This study also documented applicability of the dataset to better understand ecology of AM fungal taxa.

Integrative approach to species delimitation in Rhizophydiales: Novel species of Angulomyces, Gorgonomyces, and Terramyces from northern Thailand.

The Chytridiomycota is a phylum of zoosporic eufungi that inhabit terrestrial, freshwater, and oceanic habitats. Within the phylum, the Rhizophydiales contains several monotypic families theorized to hold a diverse assemblage of fungi yet to be discovered and properly described. Based on morphology alone, many species in this order are difficult or impossible to identify. In this study, we isolated three chytrids from northern Thailand. Phylogenetic analyses placed the isolates in three monotypic genera within Rhizophydiales. Intrageneric genetic distances in the internal transcribed spacer (ITS) ranged between 1.5 and 8.5%. Angulomyces solicola sp. nov. is characterized by larger sporangia, spores, and fewer discharge papilla than A.argentinensis; Gorgonomyces thailandicus sp. nov. has larger zoospores and fewer discharge papillae in culture compared to G. haynaldii; Terramyces chiangraiensis sp. nov. produces larger sporangia than T. subangulosum. We delimited species of Angulomyces, Gorgonomyces and Terramyces using a tripartite approach that employed phylogeny, ITS genetic distances and Poisson tree processes (PTP). Results of these approaches suggest more than one species in each genus. This study contributes to the knowledge of chytrids, an understudied group in Thailand and worldwide.

Impact of environmental factors on diversity of fungi in sediments from the Shenzhen River Estuary.

In this study, to explore the relationship between environmental factors and fungal diversity in the Shenzhen River ecosystem, multiple methods including chemical analysis, culture isolation, qPCR analysis of fungal ITS region and ITS-based Illumina next-generation-sequencing were integrated. A total of 115 isolates were finally isolated and could be classified into 23 genera. Top three abundant genera isolated were Meyerozyma (18 strains), Aspergillus (17 strains) and Penicillium (14 strains). Based on the Illumina sequencing approach, 829 OTUs were affiliated to seven phyla, 17 known classes, and 162 genera, indicating the Shenzhen estuary sediments are rich in fungal diversity. The major fungal genera were Meyerozyma, Trichoderma and Talaromyces. Environmental factors showed a gradient change in Shenzhen estuary, and fungal abundance was only significantly correlated with NH4+. Shannon index was significantly correlated with pH and IC (P < 0.05). Principal coordinate analysis based on OTU level grouped into three clusters among sampling sites along with the IC and pH gradient. Functional guilds analysis suggests most of the fungi in this studying area were almost all saprotrophs, suggesting a large number of saprophytic fungi may play a significant role in the organic matter decomposition and nutrient cycling process. In summary, this study will deepen our understanding of fungi community in Shenzhen River ecosystem and their distribution and potential function shaped by environmental factors.

The hidden world of fish fungal pathogens: molecular identification and phylogenetic analysis in common carp, Cyprinus carpio.

Fungal infections pose a significant threat to aquaculture, causing substantial economic losses and ecological disruptions. The common carp (Cyprinus carpio), as a crucial farmed fish, requires in-depth research to uncover the underlying fungal pathogens affecting its health. In this study, we analyzed 150 samples of C. carpio to identify the fungal pathogens responsible for the infections based on clinical signs and symptoms. Further, we assessed fungal diversity and prevalence in the infected fish. The infected fish exhibited varying degrees of gross pathogenicity, with fins and skin heavily affected, intermediate infection observed in the head and gills, and the least infection found in the operculum. Morphological examination revealed distinct characteristics such as necrosis, lesions on the skin, fins, and gills, as well as loss of scales, hemorrhagic lesions, and red spots. Furthermore, the presence of gray and white cottony patches on the body confirmed ascomycete and zygomycete infections, while a dark white cottony mass indicated phycomycete infection. Some fish exhibited severe fungal infections, presenting prominently curved spines and necrosis with red spots on the skin. These isolates belonged to various fungal groups, including ascomycetes, zygomycetes, phycomycetes, deuteromycetes, and basidiomycetes. Among these, Fusarium oxysporum emerged as the most prevalent fungal pathogen, followed by Fusarium solani, Saprolegnia delica, and Saprolegnia parasitica. Molecular identification based on ITS and LSU rRNA sequences confirmed the presence of Saprolegnia delica, Mucor hiemalis, Coniothyrium telephii, Rhodotorula mucilaginosa, Penicillium cellarum, and Fusarium californicum in the fish samples. Phylogenetic analysis further supported the morphological and molecular data, providing insights into the relationship between the isolated fungal strains and known species from various geographical regions. Our study enhances our understanding of the diversity and prevalence of fish fungal pathogens in common carp, emphasizing the significance of employing molecular techniques for accurate identification. These comprehensive findings offer essential insights into the impact of fungal infections on common carp populations, laying the groundwork for targeted control measures to mitigate their effects on global aquaculture.

Ecological drivers of fine-scale distribution of arbuscular mycorrhizal fungi in a semiarid Mediterranean scrubland.

BACKGROUND AND AIMS: Arbuscular mycorrhizal (AM) fungi enhance the uptake of water and minerals by the plant hosts, alleviating plant stress. Therefore, AM fungal-plant interactions are particularly important in drylands and other stressful ecosystems. We aimed to determine the combined and independent effects of above- and below-ground plant community attributes (i.e. diversity and composition), soil heterogeneity and spatial covariates on the spatial structure of the AM fungal communities in a semiarid Mediterranean scrubland. Furthermore, we evaluated how the phylogenetic relatedness of both plants and AM fungi shapes these symbiotic relationships. METHODS: We characterized the composition and diversity of AM fungal and plant communities in a dry Mediterranean scrubland taxonomically and phylogenetically, using DNA metabarcoding and a spatially explicit sampling design at the plant neighbourhood scale. KEY RESULTS: The above- and below-ground plant community attributes, soil physicochemical properties and spatial variables explained unique fractions of AM fungal diversity and composition. Mainly, variations in plant composition affected the AM fungal composition and diversity. Our results also showed that particular AM fungal taxa tended to be associated with closely related plant species, suggesting the existence of a phylogenetic signal. Although soil texture, fertility and pH affected AM fungal community assembly, spatial factors had a greater influence on AM fungal community composition and diversity than soil physicochemical properties. CONCLUSIONS: Our results highlight that the more easily accessible above-ground vegetation is a reliable indicator of the linkages between plant roots and AM fungi. We also emphasize the importance of soil physicochemical properties in addition to below-ground plant information, while accounting for the phylogenetic relationships of both plants and fungi, because these factors improve our ability to predict the relationships between AM fungal and plant communities.

The high diversity of Scedosporium and Lomentospora species and their prevalence in human-disturbed areas in Taiwan.

Scedosporium and Lomentospora are important opportunistic pathogens causing localized or disseminated infection in humans. Understanding their environmental distribution is critical for public hygiene and clinical management. We carried out the first environmental survey in urbanized and natural regions in Taiwan. Overall, Scedosporium and Lomentospora species were recovered in 132 out of 273 soil samples (48.4%) across Taiwan. We morphologically and molecularly identified six Scedosporium and one Lomentospora species. All four major clinical relevant species were isolated with high frequency, i.e., Scedosporium apiospermum (42.4%), S. boydii (21.8%), Lomentosporaprolificans (14.5%), S. aurantiacum (8.5%); two clinically minor species, Pseudallescheria angusta (6.7%) and S. dehoogii (5.6%), and a saprobic species, S. haikouense (0.6%), had moderate to rare incidence. These fungal species had high incidence in urban (48.6%) and hospital (67.4%) soil samples, and had limited distribution in samples from natural regions (5%). Multivariate analysis of the fungal composition revealed strong evidence of the preferential distribution of these fungi in urban and hospital regions compared with natural sites. In addition, strong evidence suggested that the distribution and abundance of these fungal species were highly heterogeneous in the environment; samples in vicinity often yielded varied fungal communities. We concluded that these fungal species were prevalent in soil in Taiwan and their occurrences were associated with human activities. Although, hygiene sensitive sites such as hospitals were not harboring heavier fungal burdens than other urban facilities in our survey, still, aware should be taken for the high frequency of these clinical relevant species around hospital regions.

Scedosporium and Lomentospora are two fungal genera that can cause infections to wildlife and humans. Our experiment demonstrated that these fungi are ubiquitous in the soil in Taiwan. Their proximity to human-dwelling regions raises our awareness of their exposure to those who are susceptible.

Plant Gender Affects Soil Fungal Microbiota Associated with Welwitschia mirabilis, an Unusual Desert Gymnosperm.

In a recent study, we found a distinct soil bacterial community associated with male and female plants of the desert gymnosperm Welwitschia mirabilis. In this subsequent study, we also found that the soil fungal community associated with Welwitschia differs between male and female plants, and between unvegetated areas and the soil under plants. Site location, pH, and soil moisture also had an important influence on the composition of the fungal community. A number of Ascomycota and Chytrid species were found to be distinct indicators of male and female plants, respectively, but there was no overall difference at the phylum level or in terms of diversity. The unvegetated areas between plants also differed in terms of several Ascomycota OTUs. Network connectivity of the fungal communities was found to be higher under both male and female Welwitschia plants than in unvegetated control areas. As with the bacterial community, it is unclear what processes produce the gender-distinct fungal community, and also the more general plant-associated community, and also what the effects on the biology of the plants are. One possibility behind the gender-related difference in fungal community is that there are differences in the production of pollen or nectar between the two plant genders, affecting the below-ground soil community.

Soil Acidification Under Long-Term N Addition Decreases the Diversity of Soil Bacteria and Fungi and Changes Their Community Composition in a Semiarid Grassland.

Soil microorganisms play key roles in terrestrial biogeochemical cycles and ecosystem functions. However, few studies address how long-term nitrogen (N) addition gradients impact soil bacterial and fungal diversity and community composition simultaneously. Here, we investigated soil bacterial and fungal diversity and community composition based on a long-term (17 years) N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m-2 year-1) in temperate grassland, using the high-throughput Illumina MiSeq sequencing. Results showed that both soil bacterial and fungal alpha diversity responded nonlinearly to the N input gradient and reduced drastically when the N addition rate reached 32 g N m-2 year-1. The relative abundance of soil bacterial phyla Proteobacteria increased and Acidobacteria decreased significantly with increasing N level. In addition, the relative abundance of bacterial functional groups associated with aerobic ammonia oxidation, aerobic nitrite oxidation, nitrification, respiration of sulfate and sulfur compounds, and chitinolysis significantly decreased under the highest N addition treatment. For soil fungi, the relative abundance of Ascomycota increased linearly along the N enrichment gradient. These results suggest that changes in soil microbial community composition under elevated N do not always support the copiotrophic-oligotrophic hypothesis, and some certain functional bacteria would not simply be controlled by soil nutrients. Further analysis illustrated that reduced soil pH under N addition was the main factor driving variations in soil microbial diversity and community structure in this grassland. Our findings highlight the consistently nonlinear responses of soil bacterial and fungal diversity to increasing N input and the significant effects of soil acidification on soil microbial communities, which can be helpful for the prediction of underground ecosystem processes in light of future rising N deposition.

Fungal Patterns from Soils in Madagascar: an Insight from Maromizaha Forest (Evergreen Humid Forest) to Outside (Deciduous Forest).

Soil fungal diversity was studied by next-generation sequencing and compared in two different Malagasy ecosystems, the first a New Protected Area (Maromizaha NAP) that is a rich humid evergreen forest and the second a degraded and declined deciduous forest (Andaravina) whose area has been also eroded. Both areas, however, have comparable annual rainfalls and soil pH values. So it was of interest to examine the soil fungal diversity in each system and compare them. We detected 1,817,658 reads representing Ascomycota, which were dominant in both habitats (55.9%), followed by unidentified fungi (21.5%), Basidiomycota (12.7%) and Mortierellomycota (6.7%), with Mucoromycota, Chytridiomycota, Glomeromycota and other phyla accounting for less than 5% in total. In detail, 1,142 OTUs out of 1,368 constitute the common core shared by both sampling areas, which are characterized by tropical climate, whereas 185 are Maromizaha specific and 41 Andaravina specific. The most represented guilds involve fungi related to saprotrophic behaviour, with a greater tendency towards pathotrophic mode. A significant variability in terms of richness and abundance is present within Maromizaha, which is a heterogeneous environment for fungi but also for plant composition, as it emerged from the vegetational survey of the investigated sites. A few fungal sequences match taxa from Madagascar, highlighting the scarce representativeness of fungi from this island in the fungal databases and their still low knowledge. Enlarging studies in Madagascar will help not only to unravel its largely unknown fungal biodiversity but also to give a contribution for studies on the reconstruction of the diversity of soil fungi worldwide.

Impacts of 10 Years of Elevated CO2 and Warming on Soil Fungal Diversity and Network Complexity in a Chinese Paddy Field.

Climatic change conditions (elevated CO2 and warming) have been known to threaten agricultural sustainability and grain yield. Soil fungi play an important role in maintaining agroecosystem functions. However, little is known about the responses of fungal community in paddy field to elevated CO2 and warming. Herein, using internal transcribed spacer (ITS) gene amplicon sequencing and co-occurrence network methods, the responses of soil fungal community to factorial combinations of elevated CO2 (550 ppm), and canopy warming (+2 °C) were explored in an open-air field experiment for 10 years. Elevated CO2 significantly increased the operational taxonomic unit (OTU) richness and Shannon diversity of fungal communities in both rice rhizosphere and bulk soils, whereas the relative abundances of Ascomycota and Basidiomycota were significantly decreased and increased under elevated CO2, respectively. Co-occurrence network analysis showed that elevated CO2, warming, and their combination increased the network complexity and negative correlation of the fungal community in rhizosphere and bulk soils, suggesting that these factors enhanced the competition of microbial species. Warming resulted in a more complex network structure by altering topological roles and increasing the numbers of key fungal nodes. Principal coordinate analysis indicated that rice growth stages rather than elevated CO2 and warming altered soil fungal communities. Specifically, the changes in diversity and network complexity were greater at the heading and ripening stages than at the tillering stage. Furthermore, elevated CO2 and warming significantly increased the relative abundances of pathotrophic fungi and reduced those of symbiotrophic fungi in both rhizosphere and bulk soils. Overall, the results indicate that long-term CO2 exposure and warming enhance the complexity and stability of soil fungal community, potentially threatening crop health and soil functions through adverse effects on fungal community functions.

Response of abundance, diversity, and network of rhizosphere fungal community to monoculture of cut chrysanthemum.

The effects of different monoculture years on rhizosphere fungal communities (abundance, diversity, structure, and cooccurrence network) of cut chrysanthemum were determined. Three different monoculture years were (i) planting for only 1 year (Y1), (ii) continuous monoculture for 6 years (Y6), and (iii) continuous monoculture for 12 years (Y12). Compared to the Y1 treatment, the Y12 treatment significantly decreased the rhizosphere fungal gene copy numbers but increased the potential pathogen Fusarium oxysporum (P < 0.05). Both the Y6 and Y12 treatments significantly increased fungal diversity (Shannon and Simpson indices), but Y6 had great potential to enhance fungal richness (Chao1 index) relative to the Y12 treatment. Monoculture treatments decreased the relative abundance of Ascomycota but increased that of Mortierellomycota. Four ecological clusters (Modules 0, 3, 4, and 9) were observed in the fungal cooccurrence network across the Y1, Y6, and Y12 treatments, and only Module 0 was significantly enriched in the Y12 treatment and associated with soil properties (P < 0.05). RDA (redundancy analysis) and Mantel analysis showed that soil pH and soil nutrients (organic carbon, total nitrogen, and available phosphorus) were the key factors affecting fungal communities during monoculture of cut chrysanthemum. Overall, the changes in soil properties were responsible for shaping rhizospheric soil fungal communities in long-term rather than short-term monoculture systems. KEY POINTS: • Both short- and long-term monocultures reshaped the soil fungal community structure. • Long-term monoculture enhanced the network complexity of the fungal community. • Soil pH, C and N levels mainly drove modularization in the fungal community network.

Natural occurrence of fungal endophytes in cultivated cucumber plants in Syria, with emphasis on the entomopathogen Beauveria bassiana.

A survey was conducted to investigate endophytic Beauveria spp. and associated fungi in the tissues of cucumber plants (Cucumis sativus L.) cultivated in open fields and greenhouses in some regions of Syria during 2018-2019. Cultures of fungal endophytes belonging to nine genera were obtained (frequency %): Aspergillus (87.1%), Penicillium (41.23%), Fusarium (38.15%), Beauveria (12.83%), Trichoderma (9.87%), Colletotrichum (4.36%), Cladosporium (3.54%), Alternaria (2.79%), and Chaetomium (2.2%). Only Beauveria and Trichoderma cultures were entomopathogenic. Beauveria bassiana isolates were identified morphologically and molecularly from the stems, leaves, petioles, and fruits of cucumber plants collected at seven agricultural sites. Their ability to artificially colonize all cucumber plant parts was confirmed in the laboratory using soil drench. In this study, the natural association between the endophytic entomopathogenic fungus B. bassiana and cucumber plants is newly reported. In addition, a checklist of plant species reported in the literature to harbor this fungus is also provided.

Cactus Endophytic Fungi and Bioprospecting for their Enzymes and Bioactive Molecules: A Systematic Review.

Endophytic fungi are associated with plant health and represent a remarkable source of potential of enzymes and bioactive compounds, but the diversity of endophytes remains uncertain and poorly explored, especially in Cactaceae, one of the most species-rich families adapted to growing in arid and semi-arid regions. The aim of this study was to conduct a systematic review on the diversity and bioprospecting of endophytic fungi from Cactaceae. We analysed peer-reviewed articles from seven databases using PRISMA guidelines. The results showed that the Cactaceae family is a source of new taxa, but the diversity of endophytic fungi of Cactaceae is little explored, mainly the diversity among tissues and by metagenomics. Bioprospecting studies have shown that these microorganisms can be used in the production of enzymes and larvicidal and antifungal compounds. Our results are relevant as a starting point for researchers to develop studies that expand the knowledge of plant mycobiota in arid and semi-arid ecosystems, as well as comprising a remarkable source of fungal compounds with several biotechnological applications.

Analysis of the Pathogenicity and Phylogeny of Colletotrichum Species Associated with Brown Blight of Tea (Camellia sinensis) in Taiwan.

Brown blight, a destructive foliar disease of tea, has become a highly limiting factor for tea cultivation in Taiwan. To understand the population composition of the causal agents (Colletotrichum spp.), the fungal diversity in the main tea-growing regions all over Taiwan was surveyed from 2017 to 2019. A collection of 139 Colletotrichum isolates was obtained from 14 tea cultivars in 86 tea plantations. Phylogenic analysis using the ribosomal internal transcribed spacer, glutamine synthetase gene, Apn2-Mat1-2 intergenic spacer, ß-tubulin, actin, calmodulin, and glyceraldehyde-3-phosphate dehydrogenase genes together with morphological characterization revealed three species associated with brown blight of tea; namely, Colletotrichum camelliae (95.6% of all isolates), C. fructicola (3.7%), and C. aenigma (0.7%). This is the first report of C. aenigma in Taiwan. The optimal growth temperatures were 25°C for C. camelliae and 25 and 30°C for C. fructicola and C. aenigma. Although C. fructicola and C. aenigma were more adapted to high temperature, C. camelliae was the most pathogenic across different temperatures. Regardless of whether spore suspensions or mycelial discs were used, significantly larger lesions and higher disease incidences were observed for wounded than for nonwounded inoculation and for the third and fourth leaves than for the fifth leaves. Wounded inoculation of detached third and fourth tea leaves with mycelial discs was found to be a reliable and efficient method for assessing the pathogenicity of Colletotrichum spp. within 4 days. Preventive application of fungicides or biocontrol agents immediately after tea pruning and at a young leaf stage would help control the disease.