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1.
Nematodes and fungi are both ubiquitous in marine environments, yet few studies have investigated relationships between these two groups. Microbial species share many well-documented interactions with both free-living and parasitic nematode species, and limited data from previous studies have suggested ecological associations between fungi and nematodes in benthic marine habitats. This study aimed to further document the taxonomy and distribution of fungal taxa often co-amplified from nematode specimens. A total of 15 fungal 18S rRNA phylotypes were isolated from nematode specimens representing both deep-sea and shallow water habitats; all fungal isolates displayed high pairwise sequence identities with published data in Genbank (99-100%) and unpublished high-throughput 454 environmental datasets (>95%). BLAST matches indicate marine fungal sequences amplified in this study broadly represent taxa within the phyla Ascomycota and Basidiomycota, and several phylotypes showed robust groupings with known taxa in phylogenetic topologies. In addition, some fungal phylotypes appeared to be present in disparate geographic habitats, suggesting cosmopolitan distributions or closely related species complexes in at least some marine fungi. The present study was only able to isolate fungal DNA from a restricted set of nematode taxa; further work is needed to fully investigate the taxonomic scope and function of nematode-fungal interactions.  相似文献   

2.
Despite increasing concerns about microplastic (MP) pollution in aquatic ecosystems, there is insufficient knowledge on how MP affect fungal communities. In this study, we explored the diversity and community composition of fungi attached to polyethylene (PE) and polystyrene (PS) particles incubated in different aquatic systems in north‐east Germany: the Baltic Sea, the River Warnow and a wastewater treatment plant. Based on next generation 18S rRNA gene sequencing, 347 different operational taxonomic units assigned to 81 fungal taxa were identified on PE and PS. The MP‐associated communities were distinct from fungal communities in the surrounding water and on the natural substrate wood. They also differed significantly among sampling locations, pointing towards a substrate and location specific fungal colonization. Members of Chytridiomycota, Cryptomycota and Ascomycota dominated the fungal assemblages, suggesting that both parasitic and saprophytic fungi thrive in MP biofilms. Thus, considering the worldwide increasing accumulation of plastic particles as well as the substantial vector potential of MP, especially these fungal taxa might benefit from MP pollution in the aquatic environment with yet unknown impacts on their worldwide distribution, as well as biodiversity and food web dynamics at large.  相似文献   

3.
Microplastics as an emerging threat to terrestrial ecosystems   总被引:17,自引:0,他引:17       下载免费PDF全文
Microplastics (plastics <5 mm, including nanoplastics which are <0.1 μm) originate from the fragmentation of large plastic litter or from direct environmental emission. Their potential impacts in terrestrial ecosystems remain largely unexplored despite numerous reported effects on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Hence, it is within terrestrial systems that microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle‐rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant‐pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems.  相似文献   

4.
Azevedo E  Rebelo R  Caeiro MF  Barata M 《Mycologia》2012,104(3):623-632
This survey reports the occurrence, diversity and similarity of marine fungi associated with five categories of drift substrates (Arundo donax, Phragmites australis, Spartina maritima, "other stems" and driftwood) collected on four sandy beaches of the western coast of Portugal. "Other stems" and driftwood are composite samples with a variety of identified and unidentified pieces of non-woody and woody substrates respectively. Fifty-six taxa were identified, including 38 Ascomycota and 18 anamorphic fungi. Twenty-six taxa were generalists; however several cases of "substrate recurrence" were identified. The very frequent fungi differed among the categories of studied substrates, with the exception of Corollospora maritima, very frequent on four categories. Except for S. maritima, P. australis and driftwood, cases of multiple fungal colonization were rare. S. maritima was the single substrate with five different marine fungi on one sample, as well as with the highest number of very frequent fungi, highest percentage of colonization and average number of fungi per sample. Driftwood presented the highest value of fungal richness (37 taxa) and A. donax the lowest (22 taxa). ANOSIM analysis of similarity showed that all substrates supported different fungal communities with the exception of the pair P. australis/"other stems". The effect of sample size on estimated fungal richness was tested, and the results let us conclude that, although most of the sporadic fungi (<1% occurrence) will be detected only in a very large number of samples, 60 samples of A. donax and "other stems" and 70 samples of all the other substrates may suffice to assess their respective representative marine mycota.  相似文献   

5.
Fungal biodiversity in freshwater, brackish and marine habitats was estimated based on reports in the literature. The taxonomic groups treated were those with species commonly found on submerged substrates in aquatic habitats: Ascomycetes (exclusive of yeasts), Basidiomycetes, Chytridiomycetes, and the non-fungal Saprolegniales in the Class Oomycetes. Based on presence/absence data for a large number and variety of aquatic habitats, about 3,000 fungal species and 138 saprolegnialean species have been reported from aquatic habitats. The greatest number of taxa comprise the Ascomycetes, including mitosporic taxa, and Chytridiomycetes. Taxa of Basidiomycetes are, for the most part, excluded from aquatic habitats. The greatest biodiversity for all groups occurs in temperate areas, followed by Asian tropical areas. This pattern may be an artifact of the location of most of the sampling effort. The least sampled geographic areas include Africa, Australia, China, South America and boreal and tropical regions worldwide. Some species overlap occurs among terrestrial and freshwater taxa but little species overlap occurs among freshwater and marine taxa. We predict that many species remain to be discovered in aquatic habitats given the few taxonomic specialists studying these fungi, the few substrate types studied intensively, and the vast geographical area not yet sampled.  相似文献   

6.
The fungal community associated with the terrestrial photosynthetic orchid Gymnadenia conopsea was characterized through PCR-amplification directly from root extracted DNA and cloning of the PCR products. Six populations in two geographically distinct regions in Germany were investigated. New ITS-primers amplifying a wide taxonomic range including Basidiomycetes and Ascomycetes revealed a high taxonomic and ecological diversity of fungal associates, including typical orchid mycorrhizas of the Tulasnellaceae and Ceratobasidiaceae as well as several ectomycorrhizal taxa of the Pezizales. The wide spectrum of potential mycorrhizal partners may contribute to this orchid's ability to colonize different habitat types with their characteristic microbial communities. The fungal community of G. conopsea showed a clear spatial structure. With 43 % shared taxa the species composition of the two regions showed only little overlap. Regardless of regions, populations were highly variable concerning taxon richness, varying between 5 and 14 taxa per population. The spatial structure and the continuous presence of mycorrhizal taxa on the one hand and the low specificity towards certain fungal taxa on the other hand suggest that the fungal community associated with G. conopsea is determined by multiple factors. In this context, germination as well as pronounced morphological and genetic differentiation within G. conopsea deserve attention as potential factors affecting the composition of the fungal community.  相似文献   

7.
Benthic habitats harbour a significant (yet unexplored) diversity of microscopic eukaryote taxa, including metazoan phyla, protists, algae and fungi. These groups are thought to underpin ecosystem functioning across diverse marine environments. Coastal marine habitats in the Gulf of Mexico experienced visible, heavy impacts following the Deepwater Horizon oil spill in 2010, yet our scant knowledge of prior eukaryotic biodiversity has precluded a thorough assessment of this disturbance. Using a marker gene and morphological approach, we present an intensive evaluation of microbial eukaryote communities prior to and following oiling around heavily impacted shorelines. Our results show significant changes in community structure, with pre-spill assemblages of diverse Metazoa giving way to dominant fungal communities in post-spill sediments. Post-spill fungal taxa exhibit low richness and are characterized by an abundance of known hydrocarbon-degrading genera, compared to prior communities that contained smaller and more diverse fungal assemblages. Comparative taxonomic data from nematodes further suggests drastic impacts; while pre-spill samples exhibit high richness and evenness of genera, post-spill communities contain mainly predatory and scavenger taxa alongside an abundance of juveniles. Based on this community analysis, our data suggest considerable (hidden) initial impacts across Gulf beaches may be ongoing, despite the disappearance of visible surface oil in the region.  相似文献   

8.
The data needed to derive an accurate estimate of saprobic microfungi are insufficient, incomplete and contradictory. We therefore address issues that will ultimately reveal whether there are 1.5 million global fungal species, which is the generally accepted working estimate. Our data indicates that large numbers of fungi occur on host families, such as Musaceae, host genera such as Nothofagus and individual host species such as Eucalyptus globulus, and that fungi may be specific or recurrent on different plant groups. Recent studies have shown that fungal numbers on hosts may be larger than originally thought as saprobes are organ-specific/-recurrent and changes in fungal communities occur as substrata decays. Other issues, such as the impact of geography, of methodology and of taxonomy are also addressed. There is evidence that fungi on the same host at different locations also differs; site-specific factors and geographic distance may be more important than host/substrate in shaping fungal assemblages. Methodology impacts on estimates of species diversity with many more taxa observed using indirect isolation protocols as compared to direct isolations from leaves. Our understanding of fungal species numbers in speciose genera is important. In some fungal groups accepted species have been reduced to a few species, while in other groups many cryptic species are being uncovered. While we make a number of generalisations from the studies reported here, this review also highlights some of the limitations mycologists currently have to contend with. A large body of knowledge exists for certain groups of microfungi or for microfungi occurring on certain substrata/hosts. However, it is likely that we are drawing conclusions from data that are somewhat biased toward fungi and host/substrata that are of interest to human endeavours. The discrepancy between the numbers of fungi described from only one economically important genus, Eucalyptus, and all the other members of the Myrtaceae is but one example of this bias. By incorporating the large body of work that is already available and adding appropriate complementary studies, we can accelerate our understanding of microfungal diversity and this will eventually lead us to a realistic estimate of global fungal species numbers.  相似文献   

9.
Few studies have addressed the occurrence of fungi in deep-sea sediments, characterized by elevated hydrostatic pressure, low temperature, and fluctuating nutrient conditions. We evaluated the diversity of fungi at three locations of the Central Indian Basin (CIB) at a depth of ~5,000 m using culture-independent approach. Community DNA isolated from these sediments was amplified using universal and fungal-specific internal transcribed spacers and universal 18S rDNA primer pairs. A total of 39 fungal operational taxonomic units, with 32 distinct fungal taxa were recovered from 768 clones generated from 16 environmental clone libraries. The application of multiple primers enabled the recovery of eight sequences that appeared to be new. The majority of the recovered sequences belonged to diverse phylotypes of Ascomycota and Basidiomycota. Our results suggested the existence of cosmopolitan marine fungi in the sediments of CIB. This study further demonstrated that diversity of fungi varied spatially in the CIB. Individual primer set appeared to amplify different fungal taxa occasionally. This is the first report on culture-independent diversity of fungi from the Indian Ocean.  相似文献   

10.
This paper reports on the distribution of fungal communities in aquatic habitats in tropical regions and highlights differences in the taxa observed in freshwater and marine habitats. Ascomycetes are dominant on substrata in marine environments, with few basidiomycetes and discomycetes. Equally, few freshwater basidiomycetes and discomycetes have been reported from the tropics. In marine habitats, Dothideomycetes dominate on mangrove substrata, and halosphaeriaceous species are most numerous on submerged woody substrata in coastal waters, while yeasts are common in seawater and estuarine habitats. In freshwater, Ingoldian anamorphic fungi are most numerous on decaying leaves, while ascomycetes (Dothideomycetes, Sordariomycetes) are prevalent on submerged/exposed woody substrata. Unique fungi are found in tropical waters and differ from those in temperate locations.  相似文献   

11.
The ability of soil-living oribatid mites to disperse fungal propagules on their bodies was investigated. Classical plating methods were applied to cultivate these fungi and to study their morphology. Molecular markers were used for further determination. The nuclear ribosomal large subunit and the nuclear ribosomal internal transcribed spacer of DNA extracts of the cultured fungi as well as total DNA extracts of the mites themselves, also containing fungal DNA, were amplified and sequenced. Based on phylogenetic analysis, a total of 31 fungal species from major fungal groups were found to be associated with oribatid mites, indicating that mites do not selectively disperse specific species or species groups. The detected taxa were mainly saprobiontic, cosmopolitan (e.g., Alternaria tenuissima), but also parasitic fungi (Beauveria bassiana) for whose dispersal oribatid mites might play an important role. In contrast, no mycorrhizal fungi were detected in association with oribatid mites, indicating that their propagules are dispersed in a different way. In addition, fungi that are known to be a preferred food for oribatid mites such as the Dematiacea were not detected in high numbers. Results of this study point to the potential of oribatid mites to disperse fungal taxa in soil and indicate that co-evolutionary patterns between oribatid mites and their associated fungi might be rare or even missing in most cases, since we only detected ubiquitous taxa attached to the mites.  相似文献   

12.
Dredging can have significant impacts on benthic marine organisms through mechanisms such as sedimentation and reduction in light availability as a result of increased suspension of sediments. Phototrophic marine organisms and those with limited mobility are particularly at risk from the effects of dredging. The potential impacts of dredging on benthic species depend on biological processes including feeding mechanism, mobility, life history characteristics (LHCs), stage of development and environmental conditions. Environmental windows (EWs) are a management technique in which dredging activities are permitted during specific periods throughout the year; avoiding periods of increased vulnerability for particular organisms in specific locations. In this review we identify these critical ecological processes for temperate and tropical marine benthic organisms; and examine if EWs could be used to mitigate dredging impacts using Western Australia (WA) as a case study. We examined LHCs for a range of marine taxa and identified, where possible, their vulnerability to dredging. Large gaps in knowledge exist for the timing of LHCs for major species of marine invertebrates, seagrasses and macroalgae, increasing uncertainty around their vulnerability to an increase in suspended sediments or light attenuation. We conclude that there is currently insufficient scientific basis to justify the adoption of generic EWs for dredging operations in WA for any group of organisms other than corals and possibly for temperate seagrasses. This is due to; 1) the temporal and spatial variation in the timing of known critical life history stages of different species; and 2) our current level of knowledge and understanding of the critical life history stages and characteristics for most taxa and for most areas being largely inadequate to justify any meaningful EW selection. As such, we suggest that EWs are only considered on a case-by-case basis to protect ecologically or economically important species for which sufficient location-specific information is available, with consideration of probable exposures associated with a given mode of dredging.  相似文献   

13.
Dynamics of bacterial and fungal communities on decaying salt marsh grass   总被引:4,自引:0,他引:4  
Both bacteria and fungi play critical roles in decomposition processes in many natural environments, yet only rarely have they been studied as an integrated microbial community. Here we describe the bacterial and fungal assemblages associated with two decomposition stages of Spartina alterniflora detritus in a productive southeastern U.S. salt marsh. 16S rRNA genes and 18S-to-28S internal transcribed spacer (ITS) regions were used to target the bacterial and ascomycete fungal communities, respectively, based on DNA sequence analysis of isolates and environmental clones and by using community fingerprinting based on terminal restriction fragment length polymorphism (T-RFLP) analysis. Seven major bacterial taxa (six affiliated with the alpha-Proteobacteria and one with the Cytophagales) and four major fungal taxa were identified over five sample dates spanning 13 months. Fungal terminal restriction fragments (T-RFs) were informative at the species level; however, bacterial T-RFs frequently comprised a number of related genera. Amplicon abundances indicated that the salt marsh saprophyte communities have little-to-moderate variability spatially or with decomposition stage, but considerable variability temporally. However, the temporal variability could not be readily explained by either successional shifts or simple relationships with environmental factors. Significant correlations in abundance (both positive and negative) were found among dominant fungal and bacterial taxa that possibly indicate ecological interactions between decomposer organisms. Most associations involved one of four microbial taxa: two groups of bacteria affiliated with the alpha-Proteobacteria and two ascomycete fungi (Phaeosphaeria spartinicola and environmental isolate "4clt").  相似文献   

14.
The study of fungal species diversity from marine algae is in its infancy; as now no studies have been carried out on the distribution and diversity of fungi on the surfaces of marine macroalgae where all fungal–algal interactions tend to begin. The aim of this study was to isolate and describe the culturable part of mycobiota associated with the surface of benthic marine macroalgae (epiphytic or epibiotic fungi). This is an important step in understanding their abundance, diversity and factors influencing their variability and composition. The fungal community was dominated by Ascomycetes (89%) with Eurotiales as the most abundant fungal order followed by Capnodiales, Pleosporales, and Hypocreales, while Zygomycetes was less frequent. The nature of occurrence of fungal genera on different macroalgal hosts suggests that a mix of generalists’ framework applies to fungal epiphytes of seaweeds, but the abundance of fungal taxa varied among ecological functional groups of algae, as well as macroalgal taxonomic groups, which imply host filtering. The fungal assemblages were also characterized by temporal variation with variation in temperature, pH, and salinity as the most important abiotic factors. The structure of fungal assemblages showed high beta diversity and low similarity between hosts.  相似文献   

15.
Fungi populate deep Oceans in extreme habitats characterized by high hydrostatic pressure, low temperature and absence of sunlight. Marine fungi are potential major contributors to biogeochemical events, critical for marine communities and food web equilibrium under climate change conditions and a valuable source of novel extremozymes and small molecules. Despite their ecophysiological and biotechnological relevance, fungal deep-sea biodiversity has not yet been thoroughly characterized. In this study, we describe the culturable mycobiota associated with the deepest margin of the European Western Continental Shelf: sediments sampled at the Porcupine Bank and deep-water corals and sponges sampled in the Whittard Canyon. Eighty-seven strains were isolated, belonging to 43 taxa and mainly Ascomycota. Ten species and four genera were detected for the first time in the marine environment and a possible new species of Arachnomyces was isolated from sediments. The genera Cladosporium and Penicillium were the most frequent and detected on both substrates, followed by Candida and Emericellopsis. Our results showed two different fungal communities: sediment-associated taxa which were predominantly saprotrophic and animal-associated taxa which were predominantly symbiotic. This survey supports selective fungal biodiversity in the deep North Atlantic, encouraging further mycological studies on cold water coral gardens, often overexploited marine habitats.  相似文献   

16.
As an ecotone, sandy beaches exist within a multi-dimensional mesh of environmental gradients, shaped by numerous parameters (e.g. temperature, humidity, wave action, sand particle size and salinity). These limit the proliferation of a narrow group of fungal species. Obligate arenicolous marine fungi are an ecological assemblage of sand-associated heterotrophs that inhabit sandy beaches. These organisms have evolved to cope with dynamic beach conditions, having a cosmopolitan distribution across tropical, subtropical and temperate regions. Herein we provide an overview of published works relating to the fungi of sandy beaches, focusing on the past half-century. We outline a broad range of topics in ecology including fungal adaptive traits to intertidal conditions at the morphological and genetic levels, temporal and spatial patterns in community structure, and species variations in substrate preference. Collectively, these concepts should encourage marine mycologists to embrace a holistic set of perspectives to shape the outlook for beach ecology.  相似文献   

17.
Figueira D  Barata M 《Mycologia》2007,99(1):20-23
The occurrence of marine fungi associated with, pieces of wood, driftwood and dead plant stems, in the intertidal zone of two sandy beaches on the Portuguese west coast, was surveyed for 5 mo. Out of 90 samples scanned 70% had sporulating marine fungi. Thirty-five marine fungal taxa were identified (27 Ascomycota, six anamorphic fungi and two unidentified taxa), out of which 11 species were common to both beaches. Most taxa were infrequent (< or =10%), with the exception of Kirschsteiniothelia maritima (10-20%). The average number of fungi per sample was 0.91 for both beaches. Fifteen species are new records for Portugal. Samples were examined immediately after they were taken to the laboratory, as well as after incubation in moist chamber, for up to 10 mo.  相似文献   

18.
The Internal Transcribed Spacer (ITS) regions of ribosomal DNA are widely used as markers for phylogenetic analyses and environmental sampling from a variety of organisms including fungi, plants, and animals. In theory, concerted evolution homogenizes multicopy genes so that little or no variation exists within populations or individuals. However, contrary to theory, ITS variation has been confirmed in populations and individuals from a diverse range of eukaryotes. The presence of intraspecific and intra-individual variation in multicopy genes has important implications for ecological and phylogenetic studies, yet relatively little is known about natural variation of these genes, particularly at the community level. In this study, we examined intraspecific and intra-sporocarp ITS variation by DNA sequencing from sporocarps and pooled roots from 68 species of ectomycorrhizal fungi collected at a single site in a Quercus woodland. We detected ITS variation in 27 species, roughly 40% of the taxa examined. Although intraspecific ITS variation was generally low (0.16–2.85%, mean = 0.74%), it was widespread within this fungal community. We detected ITS variation in both sporocarps and ectomycorrhizal roots, and variation was present within species of Ascomycota and Basidiomycota, two distantly related lineages within the Fungi. We discuss the implications of such widespread ITS variability with special reference to DNA-based environmental sampling from diverse fungal communities. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

19.
Gordon GJ  Gehring CA 《Mycorrhiza》2011,21(5):431-441
Recent studies using molecular analysis of ectomycorrhizas have revealed that ascomycete fungi, especially members of the order Pezizales, can be important members of ectomycorrhizal (EM) fungal communities. However, little is known about the ecology and taxonomy of many of these fungi. We used data collected during a wet and a dry period to test the hypothesis that pezizalean EM fungi associated with pinyon pine (Pinus edulis) responded positively to drought stress. We also assessed the phylogenetic relationships among six, unknown pezizalean EM fungi, common to our study sites, using rDNA sequences from the internal transcribed spacer and large subunit (LSU) regions of the ribosomal DNA. Sequences of these fungi were then compared to sequences from known taxa to allow finer-scale identification. Three major findings emerged. First, at two sites, pezizalean EM were 44–95% more abundant during a dry year than a wetter year, supporting the hypothesis that pezizalean EM fungi respond positively to dry conditions. Second, four of the six unknown pezizalean EM fungi associated with P. edulis separated from one another consistently regardless of site or year of collection, suggesting that they represented distinct taxa. Third, comparison with LSU sequences of known members of the Pezizales indicated that these four taxa grouped within the genus Geopora of the family Pyronemataceae. Our results provide further evidence of the importance of pezizalean fungi in the ectomycorrhizal symbiosis and demonstrate high local abundance of members of the genus Geopora in drought-stressed pinyon–juniper woodlands.  相似文献   

20.
We investigated the diversity and community structure of ectomycorrhizal (EcM) fungi in Pinus thunbergii stands on the eastern coast of Korea. We established two 10 × 10-m plots in six forest stands and sampled soil blocks containing rootlets of mature P. thunbergii trees. EcM roots were classified into morphological groups, and the fungal taxa associated with each morphotype were identified by sequencing the nuclear rDNA internal transcribed spacer region. Cenococcum geophilum and the Atheliales, Clavulinaceae, Russulaceae and Thelephoraceae species were the main members of the EcM fungal community, which included a total of 68 observed fungal taxa. As a whole, the community consisted of a few dominant fungal taxa, such as C. geophilum (28.6% relative abundance), and a large number of rare fungal taxa that showed low abundances and local distributions. Colonization patterns at the local site scale and at the scale of the study plots greatly differed among the EcM fungal taxa; C. geophilum was distributed extensively and was dominant in several study sites, whereas a certain Lactarius sp. was distributed locally but dominated in a given study site. We conclude with a discussion of the relationship between colonization patterns of EcM fungi and soil and environmental conditions.  相似文献   

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