Fungal Species Diversity Research Articles

Soil Fungal Communities under Pinus patula Schiede ex Schltdl. & Cham. Plantation Forests of Different Ages in Ethiopia

The cultivation of plantation forests is likely to change the diversity and composition of soil fungal communities. At present, there is scant information about these communities in Ethiopian plantation forest systems. We assessed the soil fungal communities in Pinus patula Schiede ex Schltdl. & Cham. stands aged 5, 11, or 36-years-old using DNA metabarcoding of ITS2 amplicons. The ecological conditions of each plot, such as climate, altitude, and soil, were similar. Stand age and soil fertility influenced soil fungal species diversity and ecological guilds. In total, 2262 fungal operational taxonomic units were identified, of which 2% were ectomycorrhizal (ECM). The diversity of ECM fungi was higher in the 5 and 36-year-old stands than in the 11-year-old P. patula stands. Contrary to our expectations, a high level of ECM species diversity was observed in young stands, suggesting that these ECM species could compensate for the effects of nutrient stress in these stands. Our results also suggested that the abundance of plant pathogens and saprotrophs was not affected by stand age. This study provides baseline information about fungal community changes across tree stands of different ages in P. patula plantations in Ethiopia that are likely related to ECM fungi in young stands where relatively low soil fertility prevails. However, given that the plots were established in a single stand for each age class for each treatment, this study should be considered as a case study and, therefore, caution should be exercised when applying the conclusions to other stands.

Integrated eDNA metabarcoding and morphological analyses assess spatio-temporal patterns of airborne fungal spores

Fungi represent relevant allergens and plant pathogens that can disperse on long ranges, potentially producing severe consequences on public health and agriculture. Up to 11% of the bioaerosol particles are fungal spores and mycelium fragments. Estimation of fungal species diversity in time and space is decisive but may be biased by abiotic conditions and sampling methods. Traditional morphological analyses of fungal spores have been widely applied in aerobiology in the past, while recently eDNA metabarcoding can complement these studies. Here, we used both morphological analysis (spore count and taxon identification) and high-throughput sequencing to disentangle spatio-temporal variation of fungi across Northern and Central Italy and to evaluate the detection efficiency of the two approaches. Our results showed that eDNA metabarcoding detects about three times more genera and has a higher detection efficiency than the morphological analyses. However, the efficiency is high in both spore count and eDNA metabarcoding methods when the most abundant or the rarest genera are considered but it can substantially vary between the two approaches when moderately abundant genera are analyzed. Furthermore, morphological spore determination resulted in higher variance explained by PERMANOVA analysis with respect to eDNA metabarcoding (26% and 13%, respectively), which leads to a better spatio-temporal characterization of the fungal genera. As both morphological analyses and eDNA metabarcoding methods capture significant interactions between seasons and sites, they could be preferably used as complementing approaches to reliably study airborne fungal diversity and variation.

Survey of mycobiota on Slovakian wine grapes from Small Carpathians wine region

A total of 13 samples of grapes (bunches) without apparent fungal contamination were analyzed. The samples were collected during the 2019 harvest from Vrbové village in the Small Carpathian region of Slovakia. For the isolation of fungi were used the direct plating technique on DRBC plates. The plates were incubated aerobically at 25 ±1 °C for one week in the dark. The data obtained from the cultivation of the grape berry samples revealed a high diversity of fungal species (a total of 1044 isolates were obtained). Alternaria and Rhizopus were the main components of the wine grape mycobiota of the Vrbovský subregion at harvest time (92%, each), followed by Cladosporium (85%), Penicillium (77%), Botrytis and Epicoccum (54%, each). The most abundant genera found by descending order were Penicillium (25%), Alternaria (24%), Cladosporium (20%), and Rhizopus (12%) and only in minor percentage by Aspergillus (3%) among others. The main fungal species isolated from genera Penicillium and Aspergillus were Penicillium expansum (57% RD) and A. section Nigri (97% RD). Of 17 analyzed Penicillium strains, 65% were able to produce at least one of the six mycotoxins analyzed in in vitro conditions by means of thin-layer chromatography method: citrinin, griseofulvin, patulin, cyclopiazonic acid, penitrem A, and roquefortin C.

Biodiversity of mycoplankton in the profile of eutrophic lakes with varying water quality

The aim of the study was to examine the species diversity of mycoplankton in the profiles of eutrophic lakes with different abundance of indicator microorganisms and aerobic conditions, and to check whether there are species of mycoplankton characteristic for particular layers of the studied limnic ecosystems. It has been shown that the epilimnion and metalimnion of the studied lakes are characterized by the highest abundance of mycoplankton, while the highest species diversity of these microorganisms, expressed with the Shannon-Wiener index, occurred in the epilimnion and hypolimnion. The most important factors determining the species composition and abundance of mycoplankton in eutrophic lakes are: concentration of organic matter and oxygen dissolved in the water as well as electrolytic conductivity of the water. Candida argentea had the highest stability index in lakes where the metalimnion was characterized by well oxygenated water, whereas in lakes which were characterized by a lack of oxygen in the metalimnion, the predominant species was Candida albicans . This species seems to be a very good microbiological indicator of water quality, due to its interactions with indicator bacteria, in particular Pseudomonas aeruginosa and Escherichia coli . • The highest abundance of mycobiota was in epi- and metalimnion of eutrophic lakes. • The highest species diversity of mycobiota was in the epi- and hypolimnion. • The species diversity of fungi were dependent on the quality of eutrophic waters. • C. argentea dominated in lakes with good oxygen conditions in the metalimnion. • C. albicans dominated in lakes with the anaerobic metalimnion.

Effects of chicken farming on soil organic carbon fractions and fungal communities in a Lei bamboo (Phyllostachys praecox) forest in subtropical China

Bamboo-chicken farming (BCF) is a traditional model of forestry in China that increases the rate of utilization of forest resources and the economic benefits associated with forestland use. However, little is known about the effects of BCF on soil carbon sequestration and sustainable forestland use. In this study, BCF effects on soil nutrient content, organic carbon fractions, and fungal communities were analyzed in a Lei bamboo (Phyllostachys praecox) forest. The data from five treatments (5, 15, 25, and 35 m from a hen house and the control, i.e., no chicken presence) were analyzed and compared. The results showed that BCF significantly increased (p < 0.05) soil pH, soil organic carbon, alkali-hydrolysable N, available K, and available P. However, there was no significant difference in soil organic carbon among treatments, indicating that high grazing density led to high carbon loss. The changes in the proportions of soil active organic carbon pools easily oxidized organic carbon, dissolved organic carbon, and microbial biomass carbon accounted for 7.62%–11.85%, 0.23%–0.33%, and 0.31%–0.56% of the total soil organic carbon, respectively. Easily oxidized organic carbon may be a sensitive indicator of changes in soil organic matter caused by different grazing densities. Passive organic carbon Ca-SOC and Fe/Al-SOC accounted for 1.24%–1.98% and 33.91%–37.52% of the total soil organic carbon, respectively. High Fe/Al-SOC values were associated with high grazing density, thereby implying that such condition could improve carbon sequestration in the long term. Fungal community structure and abundance varied with grazing density. Changes in fungal community composition were closely related to organic carbon fractions and soil chemical properties. Higher grazing density reduced fungal species diversity and increased the relative abundances of fungal taxa such as Ascomycota and Mortierellomycota for carbon cycling, and of saprophytes such as Fusarium. This might in turn affect soil carbon sequestration and health. Overall, our results suggest that changes in fungal community structure and soil nutrient status caused by chicken farming alters ecosystem functions; from low to high density, the increasing trend of some soil available nutrients (alkali-hydrolysable N, available K, and available P) and relative abundance of fungal taxa for soil carbon cycling, and the decreasing trend of fungal richness (Chao 1 index) may reflect a high risk of carbon and nutrient loss and a reduction of biodiversity in the BCF system.

Indoor fungal contamination as a biological risk factor

Aim. To assess the degree of fungal contamination and the species composition of the fungal microbiota of residential apartments in Kazan&#x0D; Methods. A mycological study of 90 air samples and 60 samples from sites of fungal biodeterioration from the residential buildings of Kazan was carried out using cultural and microscopic methods.&#x0D; Results. The presence of micromycetes fungi were detected in 90% of air samples and 100% of samples from sites of biodeterioration. Higher fungal species diversity was noted in the sites, compared with air samples. Fungal concentrations in indoor air varied between 8 and 360 CFU/m3. Fungal community composition analysis of the sites of biodeterioration showed that the surfaces were more frequently contaminated by undemanding and capable of growth at different moisture levels fungal species (Penicillium spp., Aspergillus spp., Rhizopus stolonifer). The resulting fungal plaque can create conditions favorable for aggressive fungal species that actively damage materials (Chaetomium spp., Acremonium spp., Aureubasidium spp). Allergenic fungi, as well as potentially pathogenic and toxin-forming species, were widespread in the air that can be a health risk factor. A quantitative assessment of air mycobiota indicated the moderate level of fungal contamination.&#x0D; Conclusion. The presence of potentially pathogenic, allergenic and biodegradable fungal species in the sites of biodeterioration has been confirmed, as well as the relationship between airborne fungal contamination and the spread of fungi in indoors, confirming the need to prevent fungal biodeterioration and control indoor air quality.

Mapping mycological ignorance \u2013 checklists and diversity patterns of fungi known for West Africa

Scientific information about biodiversity distribution is indispensable for nature conservation and sustainable management of natural resources. For several groups of animals and plants, such data are available, but for fungi, especially in tropical regions like West Africa, they are mostly missing. Here, information for West African countries about species diversity of fungi and fungus-like organisms (other organisms traditionally studied by mycologists) is compiled from literature and analysed in its historical context for the first time. More than 16,000 records of fungi representing 4843 species and infraspecific taxa were found in 860 publications relating to West Africa. Records from the Global Biodiversity Information Facility (GBIF) database (2395 species), and that of the former International Mycological Institute fungal reference collection (IMI) (2526 species) were also considered. The compilation based on literature is more comprehensive than the GBIF and IMI data, although they include 914 and 679 species names, respectively, which are not present in the checklist based on literature. According to data available in literature, knowledge on fungal richness ranges from 19 species (Guinea Bissau) to 1595 (Sierra Leone). In estimating existing species diversity, richness estimators and the Hawksworth 6:1 fungus to plant species ratio were used. Based on the Hawksworth ratio, known fungal diversity in West Africa represents 11.4% of the expected diversity. For six West African countries, however, known fungal species diversity is less than 2%. Incomplete knowledge of fungal diversity is also evident by species accumulation curves not reaching saturation, by 45.3% of the fungal species in the checklist being cited only once for West Africa, and by 66.5% of the fungal species in the checklist reported only for a single country. The documentation of different systematic groups of fungi is very heterogeneous because historically investigations have been sporadic. Recent opportunistic sampling activities in Benin showed that it is not difficult to find specimens representing new country records. Investigation of fungi in West Africa started just over two centuries ago and it is still in an early pioneer phase. To promote proper exploration, the present checklist is provided as a tool to facilitate fungal identification in this region and to aid conceptualisation and justification of future research projects. Documentation of fungal diversity is urgently needed because natural habitats are being lost on a large scale through altered land use and climate change.

Macromycetes of the Palace Park in Poznań-Radojewo (Wielkopolska Region, Poland)

This work aimed to present the diversity of fungal species in the Poznań- Radojewo park. It was characterized based on literature data, unpublished master’s theses, the authors’ data, as well as data collected during two mycological trips organized by the Mycological Section of the Polish Botanical Society. Between 1980 and 2017, as many as 333 species of macromycetes have been found within the park in Poznań-Radojewo (among them 19% are rare and endangered), including eight protected species (&lt;em&gt;Mitrophora &lt;/em&gt;&lt;em&gt;semilibera&lt;/em&gt;, &lt;em&gt;Morchella esculenta &lt;/em&gt;(var. &lt;em&gt;esculenta &lt;/em&gt;and var. &lt;em&gt;umbrina&lt;/em&gt;), &lt;em&gt;Geastrum corollinum&lt;/em&gt;, &lt;em&gt;G. fornicatum&lt;/em&gt;, &lt;em&gt;Hericium coralloides, &lt;/em&gt;and &lt;em&gt;Myriostoma coliforme&lt;/em&gt;), as well as two species new to the Polish mycobiota: &lt;em&gt;Psathyrella bipellis &lt;/em&gt;and &lt;em&gt;P. larga&lt;/em&gt;. The park in Poznań-Radojewo is very important for maintaining a high species diversity of fungi within the city of Poznań. During revitalization works, it is of paramount importance to take the needs of rare, threatened, and protected species under consideration and to preserve the natural character of plant communities. It is also vital to ensure the presence of coarse woody debris at different decomposition phases, which serves as an important substratum type for rare fungi.

Community and neighbourhood tree species richness effects on fungal species in leaf litter

Abstract Investigating the effects of individual tree species on fungal species in leaf litter allows a mechanistic understanding of how tree diversity affects the diversity and composition of fungal species at the community level. We collected freshly-fallen leaves of eight focal tree species at four tree species richness levels in a large-scale subtropical forest diversity experiment to estimate tree species richness effects on fungal species diversity and community composition at two spatial scales: at the local tree neighbourhood and at the tree community level. The identity of focal tree species affected both the diversity and composition of the fungal community in freshly-fallen leaves, particularly structuring the composition of both the pathogenic and non-pathogenic fungal community. Furthermore, we found that the effects of community tree species richness on fungal OTU composition were tree species-specific. Besides community tree species richness, the neighbour tree community had significant effects on the structure of the entire fungal community and of functional groups in freshly-fallen leaves. These findings highlight that the response of fungal species assemblages to tree species richness depends on fungal-associated tree species identity, and suggest that heterospecificity of local tree neighbours is an important driver of tree richness effects on litter fungal community.

Antimicrobial and antioxidant activities and chemical profiling of Curvularia tsudae endophytic in Cynodon dactylon (L.) Pers.

There is a growing body of evidence that endophytic fungal metabolites possess important biological activities. Cynodon dactylon (L.) Pers., a well-known grass species with potential medicinal properties, is under-explored for the diversity of endophytic fungal species and their metabolites. We report here the diversity of endophytic fungi in the culm, leaf and inflorescence of Cynodon dactylon when cultured on moist blotter (MB), potato dextrose agar (PDA) and malt extract agar (MEA). Species richness, Shannon and Simpson diversity and evenness indices showed that PDA followed by MEA supported the growth of the largest number of fungal species. Amongst four fungal species tested, Curvularia tsudae was selected for further studies on antimicrobial and antioxidant activities. The mycelial mat (MM) and culture filtrate (CF) of PD broth grown Curvularia tsudae extracted with ethyl acetate and methanol, respectively, were subjected to antimicrobial assay against five bacterial and four fungal test isolates. Results indicated that the ethyl acetate extract of CF had moderate activity against Enterococcus faecalis, Escherichia coli, Pseudomonas fluorescence and Staphylococcus aureus whereas the methanolic MM extract showed high to moderate activity to Aspergillus flavus, A. niger and Fusarium oxysporum. Cyclic voltammetric analysis of ethyl acetate extract showed very good antioxidant activity and the extract contained coumarins when determined by HPLC. High-resolution orbitrap LC-MS of ethyl acetate extract revealed the presence of metabolites with antimicrobial and antioxidant and other biological activities. Finding of the present study suggested that Curvularia tsudae could be exploited for pharmaceutical applications.

Diversity and Toxigenicity of Fungi that Cause Pineapple Fruitlet Core Rot.

The identity of the fungi responsible for fruitlet core rot (FCR) disease in pineapple has been the subject of investigation for some time. This study describes the diversity and toxigenic potential of fungal species causing FCR in La Reunion, an island in the Indian Ocean. One-hundred-and-fifty fungal isolates were obtained from infected and healthy fruitlets on Reunion Island and exclusively correspond to two genera of fungi: Fusarium and Talaromyces. The genus Fusarium made up 79% of the isolates, including 108 F. ananatum, 10 F. oxysporum, and one F. proliferatum. The genus Talaromyces accounted for 21% of the isolated fungi, which were all Talaromyces stollii. As the isolated fungal strains are potentially mycotoxigenic, identification and quantification of mycotoxins were carried out on naturally or artificially infected diseased fruits and under in vitro cultures of potential toxigenic isolates. Fumonisins B1 and B2 (FB1-FB2) and beauvericin (BEA) were found in infected fruitlets of pineapple and in the culture media of Fusarium species. Regarding the induction of mycotoxin in vitro, F. proliferatum produced 182 mg kg⁻1 of FB1 and F. oxysporum produced 192 mg kg⁻1 of BEA. These results provide a better understanding of the causal agents of FCR and their potential risk to pineapple consumers.

Humidity governs the wall-inhabiting fungal community composition in a 1600-year tomb of Emperor Yang

Biodeterioration caused by filamentous fungi is often a threat to the architectural heritage (i.e. tombs and historic sites). To specifically understand the deterioration phenomena caused by microorganisms in tombs and how these are shaped due to various environmental factors, the fungal communities in the coffin chamber of the Chinese emperor Yang (BC 569–618) were investigated at different heights using denaturant gradient gel electrophoresis (DGGE) fingerprinting. The associated environmental conditions, such as humidity, temperature, height and illumination, were also assessed. The results showed that a great diversity of fungal species (Cordyceps, Fusarium, Harpochytrium, Emericellopsis, Volutella, Cladosporium, Stachybotrys, Trichoderma, Cochlonema and two unknown fungal species) was present in emperor Yang’s coffin chamber. The predominant species were Stachybotrys, Fusarium, Trichoderma and Cochlonema. Redundancy analysis (RDA) indicated that humidity, temperature, height and illumination were the most significantly related factors shaping the fungal communities. Humidity showed the highest degree of variance description (19.2%) than all other environmental factors, followed by illumination (18.3%) and height (12.8%). Furthermore, fungal richness and diversity indices showed a positive correlation with humidity (p < 0.05). These results help in understanding the fungal community in tombs, promoting the mitigation of deterioration phenomena of such building heritage for the present and future.

Eutypella parasitica and Other Frequently Isolated Fungi in Wood of Dead Branches of Young Sycamore Maple (Acer pseudoplatanus) in Slovenia

Eutypella parasitica R.W. Davidson and R.C. Lorenz is the causative agent of Eutypella canker of maple, a destructive disease of maples in Europe and North America. The fungus E. parasitica infects the trunk through a branch stub or bark wound. Because the fungal community may have an impact on infection and colonization by E. parasitica, the composition of fungi colonizing wood of dead branches of sycamore maple (Acer pseudoplatanus L.) was investigated in five sampling sites in Slovenia. Forty samples from each sampling site were collected between the November 2017 and March 2018 period. Isolations were made from the wood in the outer part of dead branches and from discoloured wood in the trunk that originated from a dead branch. Pure cultures were divided into morphotypes, and one representative culture per morphotype was selected for further molecular identification. From a total of 2700 cultured subsamples, 1744 fungal cultures were obtained, which were grouped into 212 morphotypes. The investigated samples were colonized by a broad spectrum of fungi. The most frequently isolated species were Eutypa maura (Fr.) Sacc., Eutypa sp. Tul. and C. Tul., Fusarium avenaceum (Fr.) Sacc., Neocucurbitaria acerina Wanas., Camporesi, E.B.G. Jones and K.D. Hyde and E. parasitica. In this study, we distinguished species diversity and the fungal community. There were no significant differences in the diversity of fungal species between the five sampling sites, and branch thickness did not prove to be a statistically significant factor in fungal species diversity. Nevertheless, relatively low Jaccard similarity index values suggested possible differences in the fungal communities from different sampling sites. This was confirmed by an analysis of similarities, which showed that the isolated fungal community distinctly differed between the five sampling sites and between the different isolation sources. Eutypella parasitica was isolated from all five investigated sampling sites, although Eutypella cankers were observed in only three sampling sites, indicating the possibility of asymptomatic infection.

Fungal communities in decomposing wood along an energy wood harvest gradient

The current requirements to decrease the consumption and greenhouse gas emissions of fossil fuels have increased the demand of renewable energy sources. In forestry, this situation has intensified harvesting practices resulting in a decreased amount of woody debris left on the clear-cut areas. Impacts of energy wood harvest on wood-decomposing fungi were studied in a large-scale experiment in clear-cut stands in three geographical areas in Finland. A sequence of treatments was expected to form a forestry induced soil disturbance gradient: (1) logging residues left at site, no soil preparation; (2) logging residues left at site, patch mounding; (3) 70% logging residue removal, patch mounding; and (4) complete stump and logging residue removal, patch mounding. Pre-weighed wood discs were incubated on the intact soil cover for four years to estimate decomposition rate and fungal decomposer community. A soil sample was taken underneath each disc to evaluate the direct inoculation potential of the soil. The main results were as follows: (1) The differences between the treatments were not significant, while the geographical factors affected the decomposition rate and the fungal communities of the wood discs. (2) The fungal composition in the wood discs did not reflect the underlying soil fungal community, which indicates that a part of the fungal species inhabiting wood discs originated from airborne surrounding sources. (3) The increase in fungal species diversity was associated to the wood decay process, indicated by parallel increase in the wood decomposition rate and the number of white rot and mycorrhizal fungi. Thus our study indicates that in addition to local environment, landscape-level factors control the decomposer fungal community and its activity in wood.

The occurrence of potentially pathogenic filamentous fungi in recreational surface water as a public health risk.

Microfungi occurring in surface water may represent an important health risk. Recreational water reservoirs are a potential reservoir of pathogenic fungi. The aim of the study was to assess the diversity of mycobiota in selected artificial bathing reservoirs with regard to its biosafety for the human population. The studies were conducted during the summer of 2016 in three research seasons (June (I), July and August (II), and September (III)), taking into account the various periods of recreational activities. Filamentous fungi were isolated from water samples collected at five different ponds utilized for recreation. From 162 water samples, 149 fungal taxa of filamentous fungi were identified: 140 were classified to species level and only nine to genus level. Aspergillus fumigatus was the dominant species. The highest species richness (S) was noted in June, with 93 fungal taxa (Menhinick's index from 2.65 to 4.49). Additionally, in season I, the highest diversity of fungal species was revealed (Simpson's diversity index from 0.83 to 0.99). The average number of CFU/1 mL sample ranged between 0.4 and 4.6 depending on the time of sampling and ponds. Of all the isolated species, 128 were clinically relevant (11 from RG-2 and 117 from RG-1), highlighting the need to introduce seasonal mycological monitoring of such reservoirs.

Basidioradulum mayi and B. tasmanicum spp. nov. (Hymenochaetales, Basidiomycota) from both sides of Bass Strait, Australia

Basidioradulum was morphologically considered to be a synonym of Xylodon. Here, its independence within Hymenochaetales is confirmed from a phylogenetic perspective. Basidioradulum radula, the generic type, is widely distributed in Northern Hemisphere. Two Southern Hemisphere species close to B. radula are newly described as B. mayi and B. tasmanicum, respectively, from Victoria and Tasmania, Australia. Basidioradulum mayi differs from B. radula by lack of cystidia. Moreover, the hymenial surface of B. radula is normally much more strongly hydnoid than that of B. mayi. Basidioradulum tasmanicum is distinct from B. radula and B. mayi by having capitate cystidia, ellipsoid to subglobose basidiospores, and crystal-covered hyphae. Although morphologically distinct, the two new species isolated by Bass Strait have an almost identical ITS region, and could not be differentiated by nLSU- and ITS-based phylogenetic analyses. This case reminds us that basing phylogeny simply on the ITS as a barcode region may underestimate fungal species diversity.

Can dynamic network modelling be used to identify adaptive microbiomes?

Abstract In recent times, interest has grown in understanding how microbiomes – the collection of microorganisms in a specific environment – influence the survivability or fitness of their plant and animal hosts. The profound diversity of bacterial and fungal species found in certain environments, such as soil, provides a large pool of potential microbial partners that can interact in ways that reveal patterns of associations linking host–microbiome traits developed over time. However, most microbiome sequence data are reported as a community fingerprint, without analysis of interaction networks across microbial taxa through time. To address this knowledge gap, more robust tools are needed to account for microbiome dynamics that could signal a beneficial change to a plant or animal host. In this paper, we discuss applying mathematical tools, such as dynamic network modelling, which involves the use of longitudinal data to study system dynamics and microbiomes that identify potential alterations in microbial communities over time in response to an environmental change. In addition, we discuss the potential challenges and pitfalls of these methodologies, such as handling large amounts of sequencing data and accounting for random processes that influence community dynamics, as well as potential ways to address them. Ultimately, we argue that components of microbial community interactions can be characterized through mathematical models to reveal insights into complex dynamics associated with a plant or animal host trait. The inclusion of interaction networks in microbiome studies could provide insights into the behaviour of complex communities in tandem with host trait modification and evolution. A free Plain Language Summary can be found within the Supporting Information of this article.

Wide diversity of fungal species found in wellwater for human consumption: an analytical cross-sectional study.

Fungi are ubiquitous in the environment. They are able to grow in water and many of them may be opportunistic pathogens. The aims were to identify fungi in registered wells (RWs) and nonregistered wells (NRWs) that tap into groundwater; and to correlate the results from physicochemical assays on this water (free residual chlorine and pH) with the presence of fungi. Analytical cross-sectional quantitative study on groundwater wells in São José do Rio Preto, São Paulo, Brazil. 52 samples of 500 ml of water were collected from RWs and 107 from NRWs. These were sent to a microbiology laboratory to identify any fungi that were present. In addition, free residual chlorine and pH were measured immediately after sample collection. Several statistical analysis tests were used. Fungal contamination was present in 78.8% of the samples from RWs and 81.3% from NRWs. Filamentous fungi were more prevalent than yeast in both types of wells. There was no significant difference in presence of fungi according to whether chloride and pH were within recommended levels in RWs; or according to whether pH was within recommended levels in NRWs. Furthermore, there was no statistical difference in the levels of fungal contamination between RWs and NRWs. Both RWs and NRWs are potential reservoirs for many types of fungi. Many of these may become opportunistic pathogens if they infect immunosuppressed individuals. Furthermore, this study confirms that fungi are able to grow even when chlorine and pH parameters are within the standards recommended.

Temporal-spatial variations of fungal composition in PM2.5 and source tracking of airborne fungi in mountainous and urban regions

Fungi are ubiquitous in air and their composition is potentially important for human health. Exposure to fungal allergens has been considered as a significant risk factor due to the prevalence and severity of asthma in humans. However, temporal-spatial variations and potential sources of airborne fungi aerosol have been poorly understood. In this study, 48 PM2.5 samples were collected at two sampling sites in Xi’an from April 2018 to January 2019. High-throughput sequencing technology was used to determine the diversity and abundance of fungal composition in all samples. Microbial samples were also collected from leaf-surface and soil to identify the potential sources of fungal aerosols. Results showed that the species richness of fungi in summer and autumn inclined to be higher than that in spring and winter in mountainous and urban regions. Airborne fungal species richness and diversity at Mt. Qinling sampling site were significantly higher compared to Yanta urban sampling site, except in winter. These variations in fungal composition were significantly related to season and location. The influence of atmospheric pollutants (PM2.5, ozone, sulfur dioxide and carbon monoxide) on the richness and diversity of airborne fungal composition was higher than meteorological factors (temperature, relative humidity and wind speed). Moreover, it was observed that the leaf-surface was the primary local source of airborne fungi during all seasons at both sampling sites. Back trajectories arriving at both sampling sites showed that a considerable part of airborne fungi might have come from other regions by medium or long-range airflow. This study will provide an important reference for studying the source and temporal-spatial variations of fungal aerosols and further provide basic background data for human health exposure assessment.

Characterization and variation of the rhizosphere fungal community structure of cultivated tetraploid cotton.

Rhizosphere fungal communities exert important influencing forces on plant growth and health. However, information on the dynamics of the rhizosphere fungal community structure of the worldwide economic crop cotton (Gossypium spp.) is limited. In the present study, next-generation sequencing of nuclear ribosomal internal transcribed spacer-1 (ITS1) was performed to characterize the rhizosphere fungal communities of G. hirsutum cv. TM-1 (upland cotton) and G. barbadense cv. Hai 7124 (island cotton). The plants were grown in field soil (FS) that had been continuously cropped with cotton and nutrient-rich soil (NS) that had not been cropped. The fungal species richness, diversity, and community composition were analyzed and compared among the soil resources, cotton genotypes, and developmental stages. We found that the fungal community structures were different between the rhizosphere and bulk soil and the difference were significantly varied between FS and NS. Our results suggested that cotton rhizosphere fungal community structure variation may have been primarily influenced by the interaction of cotton roots with different soil resources. We also found that the community composition of the cotton rhizosphere fungi varied significantly during different developmental stages. In addition, we observed fungi that was enriched or depleted at certain developmental stages and genotypes in FS and NS, and these insights can lay a foundation for deep research into the dynamics of pathogenic fungi and nutrient absorption of cotton roots. This research illustrates the characteristics of the cotton rhizosphere fungal communities and provides important information for understanding the potential influences of rhizosphere fungal communities on cotton growth and health.