Fungal Species Richness Research Articles

Monitoring fungi in ecological restorations of coastal Indiana, U.S.A.

AbstractMonitoring of ecological restorations has rarely focused on fungi. In this study, we conduct a first‐ever monitoring of macrofungi in ecological restorations of coastal Indiana (U.S.A.) and present an approach and considerations that can be followed elsewhere. Forty‐two sites were surveyed over a 2‐year period for the presence of saprotrophic, mycorrhizal, and parasitic macrofungi. Sites included those considered to be restoration, prerestoration, or reference and were in wooded, semiwooded, or grassland habitats. With 1,103 observations, 277 species of fungi were identified. Most fungi were found in wooded habitats though some were in grassland restorations. Invasive plant cover negatively impacted fungal species richness. Monitored sites were compared to a set of reference sites using two different similarity indices (overlap and Jaccard), as well as the ratios of different fungal functional guilds, revealing that choice of index can impact how restorations are perceived to match targets. Last, we present a novel, tractable, and conservative way to assess and rank sites by the functional trait guilds of fungi. We show that such an approach can provide important additional information about the success of restorations such that functional guild ratios could be used as an indicator of restoration progress early‐on while functional values are better used in later phases.

Phylogenetically Structured Differences in rRNA Gene Sequence Variation among Species of Arbuscular Mycorrhizal Fungi and Their Implications for Sequence Clustering.

Arbuscular mycorrhizal (AM) fungi form mutualisms with plant roots that increase plant growth and shape plant communities. Each AM fungal cell contains a large amount of genetic diversity, but it is unclear if this diversity varies across evolutionary lineages. We found that sequence variation in the nuclear large-subunit (LSU) rRNA gene from 29 isolates representing 21 AM fungal species generally assorted into genus- and species-level clades, with the exception of species of the genera Claroideoglomus and Entrophospora However, there were significant differences in the levels of sequence variation across the phylogeny and between genera, indicating that it is an evolutionarily constrained trait in AM fungi. These consistent patterns of sequence variation across both phylogenetic and taxonomic groups pose challenges to interpreting operational taxonomic units (OTUs) as approximations of species-level groups of AM fungi. We demonstrate that the OTUs produced by five sequence clustering methods using 97% or equivalent sequence similarity thresholds failed to match the expected species of AM fungi, although OTUs from AbundantOTU, CD-HIT-OTU, and CROP corresponded better to species than did OTUs from mothur or UPARSE. This lack of OTU-to-species correspondence resulted both from sequences of one species being split into multiple OTUs and from sequences of multiple species being lumped into the same OTU. The OTU richness therefore will not reliably correspond to the AM fungal species richness in environmental samples. Conservatively, this error can overestimate species richness by 4-fold or underestimate richness by one-half, and the direction of this error will depend on the genera represented in the sample. Arbuscular mycorrhizal (AM) fungi form important mutualisms with the roots of most plant species. Individual AM fungi are genetically diverse, but it is unclear whether the level of this diversity differs among evolutionary lineages. We found that the amount of sequence variation in an rRNA gene that is commonly used to identify AM fungal species varied significantly between evolutionary groups that correspond to different genera, with the exception of two genera that are genetically indistinguishable from each other. When we clustered groups of similar sequences into operational taxonomic units (OTUs) using five different clustering methods, these patterns of sequence variation caused the number of OTUs to either over- or underestimate the actual number of AM fungal species, depending on the genus. Our results indicate that OTU-based inferences about AM fungal species composition from environmental sequences can be improved if they take these taxonomically structured patterns of sequence variation into account.

Phosphorus availabilities in beech (Fagus sylvatica L.) forests impose habitat filtering on ectomycorrhizal communities and impact tree nutrition

Phosphorus (P) is an important nutrient, whose concentrations are declining in many European forest ecosystems. Here, we selected five old-aged temperate beech (Fagus sylvatica) forests that represented a sequence of decreasing soil P resources. We addressed the following hypotheses: (i) root P concentrations correspond to soil P concentrations, when P availability is suboptimal for tree nutrition, (ii) decreasing soil P concentrations, and increasing host P demand foster increasing ectomycorrhizal fungal (EMF) species richness and lead to a shift in the EMF community structure towards increasing soil exploration. We found that the decrease in P concentrations along the geosequence was less steep in the organic layer than that in the mineral topsoil. P concentrations in roots showed a positive relationship with P concentrations in soil, with a stronger correlation in coarse than in fine roots. This finding indicates that low P availability mainly affected P storage of the host. The root tips were completely colonized with EMF. In the organic layer EMF biomass was higher than that of saprophytic fungi, and correlated with inorganic P (Pi). In the mineral topsoil EMF biomass was about 10-fold lower than in the organic layer and biomass of saprophytes and microbial P, but not that of EMF, was correlated with Pi and phosphatase activities. Based on these results, we propose that beech P nutrition was mainly achieved by EMF in the organic layer. Variation in EMF species richness was unrelated to P in soil and decreased with increasing N in the organic layer. The EMF community structures were taxonomically divergent and filtered by habitat soil chemistry in the mineral layer and Pi in the organic layer between the P-rich forest and the P-poor forest. Changes in the taxonomic structures of the EMF did not result in corresponding changes in soil exploration. In conclusion, our results support a relationship between soil P concentrations and P storage in roots, but do not support mono-causal relationships between soil P and EMF species richness or hyphal soil exploration. Our results suggest that the taxonomic dissimilarities of the EMF along the P gradient were mainly driven by Pi concentrations in the organic layer and by the nutrient resources in the mineral layer.

Short-term waterlogging increases arbuscular mycorrhizal fungal species richness and shifts community composition

Our aim was to investigate the effects of short-term waterlogging in shaping communities of the obligately aerobic AMF in roots of Populus deltoides. AMF community in populus roots was deciphered with 454-pyrosequencing method from a field plot before and after 15 days waterlogging. We found that short-term waterlogging significantly altered the AMF community as confirmed with NMDS. Indicator species analysis identified 12 AMF OTUs that shown with different relative abundance between before and after waterlogging. In contrast to expectation, short-term waterlogging increased detectable AMF species richness: 4 OTUs were detected only before and 17 only after waterlogging. Variation in abundance of dominant OTUs was possibly due to short-term waterlogging disturbance and the role of competitive release in the increase in species richness following waterlogging.

Impact of Heterobasidion root-rot on fine root morphology and associated fungi in Picea abies stands on peat soils.

We examined differences in fine root morphology, mycorrhizal colonisation and root-inhabiting fungal communities between Picea abies individuals infected by Heterobasidion root-rot compared with healthy individuals in four stands on peat soils in Latvia. We hypothesised that decreased tree vitality and alteration in supply of photosynthates belowground due to root-rot infection might lead to changes in fungal communities of tree roots. Plots were established in places where trees were infected and in places where they were healthy. Within each stand, five replicate soil cores with roots were taken to 20cm depth in each root-rot infected and uninfected plot. Root morphological parameters, mycorrhizal colonisation and associated fungal communities, and soil chemical properties were analysed. In three stands root morphological parameters and in all stands root mycorrhizal colonisation were similar between root-rot infected and uninfected plots. In one stand, there were significant differences in root morphological parameters between root-rot infected versus uninfected plots, but these were likely due to significant differences in soil chemical properties between the plots. Sequencing of the internal transcribed spacer of fungal nuclear rDNA from ectomycorrhizal (ECM) root morphotypes of P. abies revealed the presence of 42 fungal species, among which ECM basidiomycetes Tylospora asterophora (24.6% of fine roots examined), Amphinema byssoides (14.5%) and Russula sapinea (9.7%) were most common. Within each stand, the richness of fungal species and the composition of fungal communities in root-rot infected versus uninfected plots were similar. In conclusion, Heterobasidion root-rot had little or no effect on fine root morphology, mycorrhizal colonisation and composition of fungal communities in fine roots of P. abies growing on peat soils.

辽宁碱蓬根际土壤真菌多样性的季节变化及其耐盐性

PDF HTML阅读 XML下载 导出引用 引用提醒 辽宁碱蓬根际土壤真菌多样性的季节变化及其耐盐性 DOI: 10.5846/stxb201406161253 作者: 作者单位: 辽宁师范大学生命科学学院,辽宁师范大学 作者简介: 通讯作者: 中图分类号: S154.3 基金项目: 辽宁省教育厅项目(2008S135) Effect of season and variation in salinity on the rhizosphere fungal diversity of Suaeda liaotungensis Author: Affiliation: Life science college of Liaoning normal university,Life science college of Liaoning normal university Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用稀释平板法和形态学鉴定法进行了辽宁碱蓬(Suaeda liaotungensis)根际土壤真菌的分离鉴定及季节、盐度对真菌多样性的影响分析。结果表明:春、夏、秋、冬四季辽宁碱蓬根际土壤中的真菌菌落数分别为6410、4180、5730和3340,种类分别为6属13种、9属16种、11属31种、6属12种,共分离鉴定出13 属42 种真菌;其根际土壤真菌的多样性指数、丰富度指数和均匀度指数,从大到小的次序均为秋>夏>春>冬,3种指数均在秋季达到峰值;多样性指数和丰富度指数差异较大,均匀度指数波动较小,春季和冬季的均匀度指数相近。辽宁碱蓬根际土壤真菌种类明显多于无植被土壤,是无植被土壤的7倍,多样性指数和均匀度指数分别是无植被土壤的4-8倍和1-1.2倍;其根际土壤真菌优势种群包括青霉属(Penicillium)、葡萄穗霉属(Stachybotrys)、枝孢属(Cladosporium)、木霉属(Trichoderma)、 曲霉属(Aspergillus)和镰孢属(Fusarium);4个季节的优势菌不尽相同,但均有一个共同的优势菌属青霉属。以NaCl浓度梯度法制造盐胁迫生境,检测辽宁碱蓬根际土壤真菌对盐胁迫的响应,结果表明:60%左右的菌种能耐受5%以下盐度、15%左右的菌种能耐10%-20%盐度;筛选出了6株高度耐盐菌:细交链孢霉、草酸青霉、产黄青霉、烟曲霉、细极链格孢和赭曲霉,其中最高耐盐菌种赭曲霉可耐20%盐度。创新之处在于以盐度和季节为变量检测辽宁碱蓬根际土壤真菌的种群构成,为其深入研究奠定了理论基础。 Abstract:Liaoning Province is one of the major habitats of Suaeda liaotungensis in China, but little is known about the population structure and distribution characteristics of the fungal species in the rhizosphere soil of this species. In present study, the fungal species from rhizosphere soil of Suaeda liaotungensis was isolated and identified using soil dilution-plate and traditional morphological methods. The effects of variations in season and salinity on the fungal diversity in the rhizosphere soil were analyzed. The experimental results showed that 6410, 4180, 5730, and 3340 fungal colonies developed from rhizosphere soil in spring, summer, autumn and winter, respectively. These were classified into 6 genera and 13 species for spring, 9 genera and 16 species for summer, 11 genera and 31 species for autumn, and 6 genera and 12 species for winter. Thirteen genera and 42 fungal species were isolated from Suaeda liaotungensis rhizosphere soil and identified, among which Penicillium, Stachybotrys, Cladosporium, Trichoderma, Aspergillus and Fusarium were the dominant genera. The fungal population structure and composition in Suaeda liaotungensis rhizosphere soil differed between seasons. The magnitude of the Shannon diversity index, richness index, and evenness index of rhizosphere fungi for different seasons, occurred in the following order: autumn > summer > spring > winter. The Shannon diversity index, richness index, and evenness index were the highest in autumn. The richness of fungal species in the rhizosphere soil of Suaeda liaotungensis was nearly seven times that in non-vegetated soil. The Shannon diversity index and evenness index of rhizosphere fungi were 4-8 and 1-1.2 times, respectively, as high as those for non-vegetated soil. Experimental salt-stress habitats were constructed using a NaCl concentration gradient method for affecting the diversity of fungal species in the rhizosphere soil of Suaeda liaotungensis. The result showed that about 60% of fungi could tolerate media with less than 5% NaCl, and nearly 15% were able to grow in media with higher than 10% NaCl. Aspergillus fumigatus and Alternaria tenuissima were tolerant to 16% NaCl or higher. Aspergillus ochraceus, the most salt-tolerant fungus, was tolerant to 20% NaCl. Our results demonstrated that factors such as climate and living environment evidently affected the fungal diversity and similarity in the rhizosphere soil of Suaeda liaotungensis. The innovation of this paper is to study the effect of change in season and salinity on the fungal diversity from rhizosphere soil of Suaeda liaotungensis. Thus, it has significance for further study of Suaeda rhizome fungal diversity. Therefore, the aims of the study were to analyze the fungal diversity in rhizosphere soil of Suaeda liaotungensis in different seasons, to analyze the influence of salinity on the rhizome fungal diversity, to collect potentially economic fungal resources, and to understand the protective effects of Suaeda liaotungensis on soil fungi. 参考文献 相似文献 引证文献

Arbuscular mycorrhizal fungal diversity in wheat agro-ecosystems in Southern Chile and effects of seed treatment with natural products

Arbuscular mycorrhizal (AM) fungi are important for P uptake in Andisols cultivated with wheat. We assessed AM fungal diversity in field experiments established with wheat cultivated after AM host plants and non-host plants at three locations of the Araucania Region. Wheat seed was treated with two natural products: Fosfobio (FOS), mixture of P-solubilizing bacteria and N2-fixing bacteria; and Myconate (MYC), product containing formononetin. For investigations of AM fungal diversity, soil samples were taken before planting and after harvest of wheat. The morphological spore analyses resulted in 26 species, belonging to 10 families and 16 genera; 5 species belonged to Acaulospora (31.2% of total), and 3 to Claroideoglomus (18.8%). Claroideoglomus claroideum was the prevalent while Ambispora leptoticha, Dominikia aurea, and Glomus badium presented the lowest frequency.The AM fungal species distribution was strongly dependent on the location, and richness at planting of wheat was higher when a non-host for AM fungi had been grown before. There appeared to be a tendency that through wheat cultivation, the richness of AM fungal species decreased from time of planting to harvest when the pre-crop was a non-host; when the pre-crop was AM host there was no apparent decrease in AM species richness through wheat cultivation. Natural products did not significantly influence grain yields. However, there was a tendency that MYC increased average grain yields by 7%. It is discussed that increased AM root colonization, as by MYC and improved P-uptake by AM fungi is more important than inoculation of seed with P-solubilizing microbes.

Euphorbia plant latex is inhabited by diverse microbial communities.

The antimicrobial properties and toxicity of Euphorbia plant latex should make it a hostile environment to microbes. However, when specimens from Euphorbia spp. were propagated in tissue culture, microbial growth was observed routinely, raising the question whether the latex of this diverse plant genus can be a niche for polymicrobial communities. Latex from a phylogenetically diverse set of Euphorbia species was collected and genomic microbial DNA extracted. Deep sequencing of bar-coded amplicons from taxonomically informative gene fragments was used to measure bacterial and fungal species richness, evenness, and composition. Euphorbia latex was found to contain unexpectedly complex bacterial (mean: 44.0 species per sample; 9 plants analyzed) and fungal (mean: 20.9 species per sample; 22 plants analyzed) communities using culture-independent methods. Many of the identified taxa are known plant endophytes, but have not been previously found in latex. Our results suggest that Euphorbia plant latex, a putatively hostile antimicrobial environment, unexpectedly supports diverse bacterial and fungal communities. The ecological roles of these microorganisms and potential interactions with their host plants are unknown and warrant further research.

Characterization saprobic fungi on leaf litter of two species of trees in the Atlantic Forest, Brazil.

We investigated the composition and structure of fungal communities associated with leaf litter generated by Clusia nemorosa and Vismia guianensis that belong to phylogenetically-related botanical families and exist together in a remnant of the Atlantic Forest in Bahia, Brazil. Samplings were conducted during wet (June 2011) and dry (January 2013) seasons in Serra da Jibóia. The fungi were isolated using particle filtration and the 1,832 isolates represented 92 taxa. The wet season yielded the largest number of isolates (1,141) and taxa (76) compared with the dry season (641 isolates and 37 taxa). The richness and diversity of fungal species associated with C. nemorosa (64 taxa, Simpson=0.95)were higher compared with those of V.guianensis (59 taxa, Simpson =0.90). Analysis of similarity (ANOSIM) revealed significant variations in the composition and community structure of fungi isolated from the two plants as a function of seasons. In contrast, nonmetric multidimensional scaling (NMDS) analysis show that the seasonality was an important influence on the distribution of fungal species. However, the populations of the saprobic fungal communities were dynamic, and several factors may influence such communities in the Atlantic Forest.

Litter quality and temperature modulate microbial diversity effects on decomposition in model experiments

The consequences of decline in biodiversity for ecosystem functioning is a major concern in soil ecology. Recent research efforts have been mostly focused on terrestrial plants, while, despite their importance in ecosystems, little is known about soil microbial communities. This work aims at investigating the effects of fungal and bacterial species richness on the dynamics of leaf litter decomposition. Synthetic microbial communities with species richness ranging from 1 to 64 were assembled in laboratory microcosms and used in three factorial experiments of decomposition. Thereafter, the functionality of the different microcosms was determined by measuring their capability to decompose materials with different chemical properties, including two species of litter (Quercus ilex L. and Hedera helix L.), cellulose strips and woody sticks. Incubation was done in microcosms at two temperatures (12°C and 24°C) for 120 days. The number of microbial species inoculated in the microcosms positively affected decomposition rates of Q. ilex and H. helix litters, while relationships found for cellulose and wood were not statistically significant. Diversity effect was greater at higher incubation temperature. We found lower variability of decay rates in microcosms with higher inoculated species richness of microbial communities. Our study pointed out that the relationships between inoculum microbial diversity and litter decomposition is dependent on temperature and litter quality. Therefore, the loss of microbial species may adversely affects ecosystem functionality under specific environmental conditions.

Patterns of laccase and peroxidases in coarse woody debris of Fagus sylvatica, Picea abies and Pinus sylvestris and their relation to different wood parameters

Lignin and its degradation, particularly in forest ecosystems, play a major role in the global carbon cycle. Filamentous fungi equipped with extracellular oxidoreductases (oxidative enzymes), i.e., laccase, manganese-dependent peroxidases and several other peroxidases, are the key players in the bioconversion of lignin. In particular, for coarse woody debris (CWD), this process is poorly understood and the activities of laccase and peroxidases have never been studied on a large field scale. We investigated the activities of these enzymes in 701 samples of Fagus sylvatica, Picea abies and Pinus sylvestris CWD across three regions in Germany and analyzed their dependence on pH, water content, wood density, total lignin, organic extractives, metals, water-soluble lignin fragments and fungal species richness. Respective enzyme activities were present in 79 % of all samples, and the activities were highly variable and more frequent in F. sylvatica than in coniferous wood. Logistic regressions and correlations between enzyme activities and the variables revealed that the fungal community structure and the amount of water-soluble lignin fragments are most important determinants, and that the prevalent acidic pH in CWD is suitable to facilitate laccase and manganese peroxidase activities. Concentrations of metals (manganese, copper, iron) were sufficient to ensure synthesis and functioning of relevant enzymes. Based on this large field study, we conclude that laccase and peroxidases in CWD are highly relevant for lignin degradation, but the variable pattern of their secretion is the result of a complex array of wood parameters and the fungal community structure, which could only partly be resolved.

Fungal diversity in grape must and wine fermentation assessed by massive sequencing, quantitative PCR and DGGE

The diversity of fungi in grape must and during wine fermentation was investigated in this study by culture-dependent and culture-independent techniques. Carignan and Grenache grapes were harvested from three vineyards in the Priorat region (Spain) in 2012, and nine samples were selected from the grape must after crushing and during wine fermentation. From culture-dependent techniques, 362 isolates were randomly selected and identified by 5.8S-ITS-RFLP and 26S-D1/D2 sequencing. Meanwhile, genomic DNA was extracted directly from the nine samples and analyzed by qPCR, DGGE and massive sequencing. The results indicated that grape must after crushing harbored a high species richness of fungi with Aspergillus tubingensis, Aureobasidium pullulans, or Starmerella bacillaris as the dominant species. As fermentation proceeded, the species richness decreased, and yeasts such as Hanseniaspora uvarum, Starmerella bacillaris and Saccharomyces cerevisiae successively occupied the must samples. The “terroir” characteristics of the fungus population are more related to the location of the vineyard than to grape variety. Sulfur dioxide treatment caused a low effect on yeast diversity by similarity analysis. Because of the existence of large population of fungi on grape berries, massive sequencing was more appropriate to understand the fungal community in grape must after crushing than the other techniques used in this study. Suitable target sequences and databases were necessary for accurate evaluation of the community and the identification of species by the 454 pyrosequencing of amplicons.

The Bacterial and Fungal Diversity of an Aged PAH- and Heavy Metal-Contaminated Soil is Affected by Plant Cover and Edaphic Parameters.

Industrial wasteland soils with aged PAH and heavy metal contaminations are environments where pollutant toxicity has been maintained for decades. Although the communities may be well adapted to the presence of stressors, knowledge about microbial diversity in such soils is scarce. Soil microbial community dynamics can be driven by the presence of plants, but the impact of plant development on selection or diversification of microorganisms in these soils has not been established yet. To test these hypotheses, aged-contaminated soil samples from a field trial were collected. Plots planted with alfalfa were compared to bare soil plots, and bacterial and fungal diversity and abundance were assessed after 2 and 6 years. Using pyrosequencing of 16S rRNA gene and ITS amplicons, we showed that the bacterial community was dominated by Proteobacteria, Actinobacteria, and Bacteroidetes and was characterized by low Acidobacteria abundance, while the fungal community was mainly represented by members of the Ascomycota. The short-term toxic impact of pollutants usually reduces the microbial diversity, yet in our samples bacterial and fungal species richness and diversity was high suggesting that the community structure and diversity adapted to the contaminated soil over decades. The presence of plants induced higher bacterial and fungal diversity than in bare soil. It also increased the relative abundance of bacterial members of the Actinomycetales, Rhizobiales, and Xanthomonadales orders and of most fungal orders. Multivariate analysis showed correlations between microbial community structure and heavy metal and PAH concentrations over time, but also with edaphic parameters (C/N, pH, phosphorus, and nitrogen concentrations).

Implications of reserve size and forest connectivity for the conservation of wood-inhabiting fungi in Europe

Among the factors that affect the conservation efficiency of protected areas, lack of connectivity is considered as one of the main problems. In this study, we assessed the influence of connectivity of European beech forest reserves on wood-inhabiting fungal communities, compared to the influence of local factors. To address this topic, we used a data matrix consisting of 344 fungal species on 1571 resource units (i.e. fallen beech logs, including their standing snags) sampled in 42 European beech forest reserves. Our results show that connectivity has significant effects on wood-inhabiting fungal communities in European beech forest reserves, and that the effectiveness of reserves for maintaining the wood-inhabiting fungal diversity is compromised by habitat fragmentation. Connectivity at small scales (measured as the area of the reserve) had a strong influence on the occurrence of indicator species and was also critical for the number of species at a resource. Connectivity at larger scales (connectivity to surrounding beech forests) seemed to be particularly critical for the community composition both at resource and reserve levels. In line with previous research, we found other covariates such as size of the resource units and annual temperature range to positively influence wood-inhabiting fungal species richness. The effects of habitat fragmentation were especially strong in western and northern European regions where the smallest and more isolated reserves were located. We propose that an effective conservation strategy for wood-inhabiting fungi should focus on increasing the areas of the present reserves as well as conserving new reserves in the proximity of the existing ones.

Dead wood characteristics influencing macrofungi species abundance and diversity in Caspian natural beech (Fagus orientalis Lipsky) forests

Aim of study: This study aimed to examine the dead wood inhabiting macrofungi communities occurring on dead beech and hornbeam trees in Caspian forests.Area of study: The Kheiroud forest in the north of Iran.Material and Methods: Data from 205 sampling dead tree were analyzed by means of Generalized Linear Models (GLM) to test the effects of decay stage, DBH, Length or Height on macrofungi diversity. Additionally, tree species, dead wood size, log position, decay stage were used as predictor factors for the number of sporocarps species (NSS) as a fungal species richness and diversity in each dead log using analysis of varianceMain results: The number of sporocarps species (NSS) varied in different dead wood size and decay classes. The different stages of decay and the different size classes of dead wood had significantly different species richness of macrofungi. Deadwood in the high-decayed stages contained the highest diversity of fungi. Most of fungi identified on both logs and snags belonged to Basidiomycetes and Ascomycetes. The highest value for richness and evenness indices calculated in large diameter dead wood in decay class III. The results indicated the size and decay class of dead wood describe the greatest variance of the model that means the highest number of sporocarps species inhabited on the large dead wood in advanced stage of decaying.Research highlights: Macrofungi diversity varied significantly across pieces of dead wood with downed logs, larger pieces, and wood in later stages of decay having the highest macrofungi diversity. Keywords: Caspian forest; coarse woody debris; down woody debris; Iran.

Drivers of CO2 Emission Rates from Dead Wood Logs of 13 Tree Species in the Initial Decomposition Phase

Large dead wood is an important structural component of forest ecosystems and a main component of forest carbon cycles. CO2 emissions from dead wood can be used as a proxy for actual decomposition rates. The main drivers of CO2 emission rates for dead wood of temperate European tree species are largely unknown. We applied a novel, closed chamber measurement technique to 360 dead wood logs of 13 important tree species in three regions in Germany. We found that tree species identity was with 71% independent contribution to the model (R2 = 0.62) the most important driver of volume-based CO2 emission rates, with angiosperms having on average higher rates than conifers. Wood temperature and fungal species richness had a positive effect on CO2 emission rates, whereas wood density had a negative effect. This is the first time that positive fungal species richness—wood decomposition relationship in temperate forests was shown. Certain fungal species were associated with high or low CO2 emission rates. In addition, as indicated by separate models for each tree species, forest management intensity, study region, and the water content as well as C and N concentration of dead wood influenced CO2 emission rates.

Cohort Study of Airway Mycobiome in Adult Cystic Fibrosis Patients: Differences in Community Structure between Fungi and Bacteria Reveal Predominance of Transient Fungal Elements.

The respiratory mycobiome is an important but understudied component of the human microbiota. Like bacteria, fungi can cause severe lung diseases, but their infection rates are much lower. This study compared the bacterial and fungal communities of sputum samples from a large cohort of 56 adult patients with cystic fibrosis (CF) during nonexacerbation periods and under continuous antibiotic treatment. Molecular fingerprinting based on single-strand conformation polymorphism (SSCP) analysis revealed fundamental differences between bacterial and fungal communities. Both groups of microorganisms were taxonomically classified by identification of gene sequences (16S rRNA and internal transcript spacer), and prevalences of single taxa were determined for the entire cohort. Major bacterial pathogens were frequently observed, whereas fungi of known pathogenicity in CF were detected only in low numbers. Fungal species richness increased without reaching a constant level (saturation), whereas bacterial richness showed saturation after 50 patients were analyzed. In contrast to bacteria, a large number of fungal species were observed together with high fluctuations over time and among patients. These findings demonstrated that the mycobiome was dominated by transient species, which strongly suggested that the main driving force was their presence in inhaled air rather than colonization. Considering the high exposure of human airways to fungal spores, we concluded that fungi have low colonization abilities in CF, and colonization by pathogenic fungal species may be considered a rare event. A comprehensive understanding of the conditions promoting fungal colonization may offer the opportunity to prevent colonization and substantially reduce or even eliminate fungus-related disease progression in CF.

Arbuscular mycorrhizal fungal species composition, propagule density, and soil alkaline phosphatase activity in response to continuous and alternate no-tillage in Northern China

PurposeArbuscular mycorrhizal (AM) fungi provide a direct link between soil and roots, and are renowned for their ability to increase nutrient phytoavailability, notably phosphorus (P). The objective of this study was to evaluate influences of continuous and alternate no-tillage on soil AM fungal species composition and soil P-supply parameters. Materials and methodsIn June 2006, a long-term field experiment was established in a sandy loam soil under the rotation of summer maize (Zea mays L.) and winter wheat (Triticum aestivum L.) in Northern China, including conventional tillage (CT), no-tillage (NT) and alternate tillage (AT — tillage in the wheat season and no-tillage in the maize season). Top soil samples (0–15cm) from four individual plots per treatment were collected before maize harvest on 18 September 2010. Soil AM fungal spores were isolated and identified, and the external mycelium length, soil alkaline phosphatase (ALP) activity and soil P content were also determined. Results and discussionThirty species of AM fungi within seven genera, Acaulospora, Claroideoglomus, Funneliformis, Glomus, Racocetra, Rhizophagus, and Scutellospora, were recovered. Some species sporulated differentially across the three treatments, and the lowest Jaccard index (J) of similarity in species composition was recorded between NT and CT (J=0.767), but there were no significant differences in soil total P and available P contents, as well as in AM fungal spore density (SD), species richness (SR) and diversity indices, including Shannon–Wiener index (H′), Evenness (E) and Simpson's index (D). Compared with CT, NT rather than AT significantly increased (P<0.05) the external mycelium length, soil ALP activity, and soil organic C content. ConclusionsOur results demonstrated the vital role of NT in maintaining external hyphae growth and soil ALP activity rather than in promoting AM fungal species diversity and spore density, and suggested that 4-year continuous NT will not cause degradation in either AM fungal community or soil P-supply efficiency.

Although Downsized, Estimate Deems Soil Fungal Diversity Substantial

Based on their analysis of some 15,000 soil samples from 365 sites, researchers from 35 institutions around the world recently revised the estimate of global fungal species downward by 1.5- to 2.5-fold from previous estimates, which range from 0.8 million to 5.1 million species. Notably, fungal species richness declines with distance from the equator and at least for some specialist groups of fungi, “diversity depends more on the abundance of host plants than host diversity or geography,” notes Leho Tedersoo of the University of Tartu Natural History Museum in Tartu, Estonia, who managed the project. Details appeared 28 November 2014 in Science (doi:10.1126/science.1256688).

Strong altitudinal partitioning in the distributions of ectomycorrhizal fungi along a short (300 m) elevation gradient.

Changes in species richness and distributions of ectomycorrhizal (ECM) fungal communities along altitudinal gradients have been attributed to changes in both host distributions and abiotic variables. However, few studies have considered altitudinal relationships of ECM fungi associated with a single host to identify the role of abiotic drivers. To address this, ECM fungal communities associated with one host were assessed along five altitudinal transects in Scotland. Roots of Scots pine (Pinus sylvestris) were collected from sites between 300 and 550-600m altitude, and ECM fungal communities were identified by 454 pyrosequencing of the fungal internal transcribed spacer (ITS) region. Soil moisture, temperature, pH, carbon:nitrogen (C:N) ratio and organic matter content were measured as potential predictors of fungal species richness and community composition. Altitude did not affect species richness of ECM fungal communities, but strongly influenced fungal community composition. Shifts in community composition along the altitudinal gradient were most clearly related to changes in soil moisture and temperature. Our results show that a 300m altitudinal gradient produced distinct shifts in ECM fungal communities associated with a single host, and that this pattern was strongly related to climatic variables. This finding suggests significant climatic niche partitioning among ECM fungal species.