Fungal Density Research Articles

Freeze tolerance of poleward‐spreading mangrove species weakened by soil properties of resident salt marsh competitor

Abstract Increasing temperatures associated with climate change are shifting plant species to higher latitudes. Soil communities could aid the plants’ shift into novel areas by harbouring fewer soil‐borne antagonists or more mutualists that influence the fitness and stress tolerance of the shifting species. Alternatively, they could contain novel antagonists or fewer mutualists. Thus, soil communities could positively or negatively affect plant range expansion, particularly if they influence plants’ responses to climate, such as freeze tolerance, that feedback to affect expansion. We used the northward range expansion of the black mangrove, Avicennia germinans, into a system dominated by marsh cordgrass, Spartina alterniflora, in northern Florida, USA to study how the novel soil environment (i.e. S. alterniflora soil) affects mangrove fitness, susceptibility to cold stress and the colonization of mutualist fungi. We quantified abundance of root mutualistic fungi in mixed marsh‐mangrove habitat and conducted a laboratory experiment to test effects of steam‐sterilized and live soils from A. germinans and S. alterniflora on the growth, condition, fungal colonization and freeze tolerance of A. germinans seedlings. In the field, we found two times higher dark septate endophyte (DSE) colonization of A. germinans roots and three times higher fungal spore density in A. germinans soil compared to S. alterniflora roots and soil. In the laboratory experiment, seedlings in steamed S. alterniflora soil treatments had 50%–65% survival after freezing, compared to 0% survival in treatments with live S. alterniflora soil. A. germinans live soil mixed with S. alterniflora steamed soil yielded A. germinans roots with the highest DSE colonization and seedlings with greater shoot biomass and lower root:shoot ratios. S. alterniflora live soil lowered the freeze tolerance of A. germinans, decreased mangrove survival and depressed DSE colonization. Synthesis. S. alterniflora soil could impede A. germinans establishment in salt marsh communities. As climate warming gradually allows A. germinans to displace S. alterniflora, the rhizosphere could become increasingly hospitable to A. germinans. Our work suggests the soil community associated with resident species mediates climatic stressors to affect expansion success.

Neighborhood effects on soil properties, mycorrhizal attributes, tree growth, and nutrient status in afforested zones

A harmonious interspecies relationship is the key to the success of mixed afforestation. This study was conducted to assess the responses of afforestation species to their neighboring trees. We examined five types of stands—monocultures of Chinese pine (Pinus tabuliformis), black locust (Robinia pseudoacacia), sea‐buckthorn (Hippophae rhamnoides), and two mixtures (Chinese pine × black locust mixture and Chinese pine × sea‐buckthorn mixture)—in the Loess Plateau, northwestern China. The height and diameter at breast height of each tree species were measured, and rhizosphere soil, shoot, and root were sampled. In monocultures, black locust was taller than Chinese pine and sea‐buckthorn, while the height of Chinese pine and sea‐buckthorn was similar. In mixtures, Chinese pine grew better with sea‐buckthorn than alone as a result of modified soil properties and plant nutrition, but not with black locust. When Chinese pine was used as neighbors, it affected the level of arbuscular mycorrhizal (AM) colonization of black locust, soil properties and AM fungal spore density of black locust and sea‐buckthorn, but did not significantly affect their growth. Our results suggest that the reciprocal effects between tree species in mixture are not symmetric, and thus planning for efficient mixed afforestation requires knowledge of species‐specific growth rate, nutrient requirements, and species interactions.

Composition of the arbuscular mycorrhizal fungal community and changes in diversity of the rhizosphere of Clematis fruticosa over three seasons across different elevations

AbstractClematis fruticosa Turcz. is a dominant native shrub with the potential for spontaneous vegetation succession for restoration of the ecologically fragile and arid Daqing Mountains of Inner Mongolia, which represent an important ecological transition zone in northern China. However, knowledge regarding the interactions between native species and their root‐associated arbuscular mycorrhizal (AM) fungi across different seasons and elevation gradients remains obscure. High AM fungal spore density, root colonization and arbuscular richness suggested that C. fruticosa could establish intimate symbiotic associations with AM fungi. A total of 174 AM fungal virtual taxa were identified from rhizosphere soil samples, and Glomus was dominant. The most distinct AM fungal community composition and the greatest richness and diversity were observed in the spring and at the highest elevation. Seasons • elevation interactions significantly affected Simpson diversity but not AM fungal community composition, observed richness and Shannon index. Seasons had a significant direct on AM fungal observed richness and Shannon index, and elevation had a significant direct on AM fungal observed richness. Soil available phosphorus was the most important driving factor in AM fungal richness and diversity, followed by seasons and soil moisture content. These results provied new insights suggesting that there are active and diverse “functional ingredients”, for example root‐associated AM fungi during the growing season, particularly with an earlier onset in the spring. They are potentially major contributors to the re‐vegetation of degraded lands and the maintenance of soil structure in arid and semiarid ecosystems, which is attributable to seasonal variation in host physiology in stressful environments.Highlights We studied the effects of seasons and elevation on AM fungal richness, diversity and community in ecologically fragile mountain areas. Distinct community composition and greater richness and diversity of AM fungi were detected in the spring and at the highest elevation. AM fungal richness and diversity depended on certain soil variation related to seasons and elevation.

Arbuscular mycorrhizal fungal community was affected by tillage practices rather than residue management in black soil of northeast China

Arbuscular mycorrhizal (AM) fungi are one of the most important soil microbes in an agrarian ecosystem, and consequently affected by various agricultural practices. To elucidate the effects of tillage practices and residue management on AM fungi, a field trial was conducted on the Songnen Plain, Northeast China. We examined the effects of different tillage practices including no-tillage (NT), rotary tillage (RT), subsoil tillage (ST) and deep tillage (DT) on the AM fungal biomass, diversity and community under residue removal and residue retention. AM root colonization and extraradical hyphal (ERH) density were significantly higher in DT treatment compared with NT treatment, whereas an opposite trend was observed for AM fungal spore density. Structural equation modeling indicated that AM fungal spore density was directly affected by tillage practices. Albeit, the effect of tillage practices on ERH density was mainly mediated through root length of maize. By Miseq sequencing of 18S rDNA, 66 AM fungal operational taxonomic units (OTUs) were identified and Glomeraceae was the most abundant group in this study. AM fungal OTU richness was highest in treatment NT, and significantly higher than that in treatment DT. Non-metric multidimensional scaling analysis indicated that treatment DT and ST induced a distinct AM fungal community composition compared with treatment NT. On the other hand, residue did not significantly influence AM fungal biomass, OTU richness and community composition. Overall, our findings indicated that tillage practice is a stronger determinant than residue management in AM fungal development and community composition in black soil on the Songnen Plain.

Symbionts as Filters of Plant Colonization of Islands: Tests of Expected Patterns and Environmental Consequences in the Galapagos.

The establishments of new organisms that arrive naturally or with anthropogenic assistance depend primarily on local conditions, including biotic interactions. We hypothesized that plants that rely on fungal symbionts are less likely to successfully colonize remote environments such as oceanic islands, and this can shape subsequent island ecology. We analyzed the mycorrhizal status of Santa Cruz Island, Galapagos flora compared with the mainland Ecuador flora of origin. We experimentally determined plant responsiveness and plant–soil feedback of the island flora and assessed mycorrhizal density and soil aggregate stability of island sites. We found that a greater proportion of the native island flora species belongs to families that typically do not associate with mycorrhizal fungi than expected based upon the mainland flora of origin and the naturalized flora of the island. Native plants benefited significantly less from soil fungi and had weaker negative soil feedbacks than introduced species. This is consistent with the observation that field sites dominated by native plant species had lower arbuscular mycorrhizal (AM) fungal density and lower soil aggregate stability than invaded field sites at the island. We found support for a mycorrhizal filter to the initial colonization of the Galapagos.

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Nghiên cứu môi trường thích hợp nhân nuôi nấm Cordyceps militaris trên vật chủ

Medicinal mushroom, Cordyceps militaris, an entomopathogenic fungus with medicinal and commercial values, is over-exploited, leading to scarcity in nature. The cultivation procedure of C. militaris on host under in vitro condition has been carried out successfully. The results showed that SDAY2 media was suitable for fast growing mycelium after 5 days of culture and large fruiting body size, very fine mycelium, cotton and reptile surface. Liquid medium CT1 showed that optimal fungal spore density after 11 days of culture, by injecting 2 mL of fungal liquid into the top of the pupal stage of Brihaspa astrostigmella, Rhynchophorus ferrugineus and Bombyx mori were highly effective, mycelium develops quickly and forms fruiting bodies, infection rate of C. militaris and Bombyx mori productivity the highest (> 95%; length 7.05 cm, diameter 2.31 mm and weight 0.32 g/fruit), cordycepin and adenosine content in the fruiting body dried to 5.25 mg/g and 0.71 mg/g, 6.1 mg/g and 0.52 mg/g, 5.34 mg/g and 0.58 mg/g respectively for Brihaspa astrostigmella, Rhynchophorus ferrugineus and Bombyx mori. These techniques can be applied to produce C. militaris mushroom on hosts to meet the market demand for current Cordyceps products.

Efecto de la biodesinfección de suelos sobre las comunidades fúngicas edáficas asociadas a cultivos hortícolas

Martin-Guirao, de Cara-Garcia, M., Tello-Marquina, J.C. 2019. Effect of soil biodisinfection on soil fungal communities associated to horticultural crops. Ecosistemas 28(3):63-72. Doi.: 10.7818/ECOS.1708 Effect of soil biodisinfection on soil fungal communities associated to horticultural crops: Soil disinfection is a common practice in horticulture, that can influence the composition and structure of edaphic microorganism communities. Bio-disinfection is a method that provokes a decrease in the pathogenic inoculum in the soil, although by incorporating organic amendments as a bio-disinfectant material, the impact on other fungal populations is not only biocide. In this work we have studied the effect of bio-disinfection with different organic materials on a cultivable fungal fraction (fungi and oomycetes) present in the soil of a greenhouse, with and without solarisation, as well as, its variation along the sequence of watermelon and tomato crops. Regardless of the addition of the bio-disinfection technique evaluated, the fungal densities and diversity of the topsoil were significantly reduced. Subsequently, the presence of fungi in the soil increased with the first crop, and remained, increasing at the end of the second crop. However, the values of micodiversity were not fully restored, with the control soil without the addition of organic matter or solarization, recovering the greatest diversity at the end of the study. The prevalence of Acremonium, Alternaria, Aspergillus, Cladosporium, Fusarium and Penicillium in most of the samples reflects a potential fungal functionality that would not be lost in these productive systems with this type of bio-disinfection. The remaining functionality is linked to soil fertility, phytopathogenicity, antagonism, or food source for other trophic levels.

AM fungal diversity and its impact across three types of mid-temperate steppe in Inner Mongolia, China.

Arbuscular mycorrhizal (AM) fungal diversity was measured in three different natural mid-temperate steppe types: the meadow steppe, typical steppe, and desert steppe. In these steppe soils, 24 AM fungal species from eight genera were identified, in which Glomus had the highest relative abundance. Funneliformis geosporus, Glomus microaggregatum, and Septoglomus constrictum had high relative abundance and were found widely across varying soil depth and steppe type. Meadow steppes had significantly higher AM fungal species richness compared to typical steppes and desert steppes, but there was no significant difference between typical steppes and desert steppes. AM fungal spore density, two Bradford-reactive soil protein (BRSP) fractions, and extraradical hyphal length densities (HLDs) were significantly different among the three steppe types. Alkaline phosphatase and acid phosphatase activity, urease activity, and soil bacterial and actinomycotic quantity were significantly related to the AM fungal spore density and species richness in these arid and semi-arid steppes. Therefore, steppe types could influence the distribution pattern of AM fungal diversity and the content of glomalin-related soil protein (GRSP).

The effect of combined application of Streptomyces rubrogriseus HDZ-9-47 with soil biofumigation on soil microbial and nematode communities

Meloidogyne incognita causes significant damage to many different crops. Previous studies showed that Streptomyces rubrogriseus HDZ-9-47 is a promising biocontrol agent. Combining it with biofumigation improved its efficacy against M. incognita. In the present study, the reason for the improved efficacy of the combination was investigated by analyzing its impact on both the soil microbial and the nematode communities in the field. The results showed that the combined application reduced root galls by 41% and its control efficacy was greater than each treatment alone. Cultivation-based analyses showed that the combination treatment affected the soil microbial community. Actinomycetes and bacterial densities were negatively correlated with the root knot score. In contrast, the fungal densities were positively correlated with the root knot score. Denaturing gradient gel electrophoresis (DGGE) results showed that the combination of S. rubrogriseus HDZ-9-47 and biofumigation enriched beneficial microbes and reduced certain soil-borne fungal phytopathogens, thereby enhancing the efficacies of both S. rubrogriseus HDZ-9-47 and biofumigation against M. incognita. And HDZ-9-47 could colonize in soil. The total abundance of nematode and plant parasites, the ratio of soil fungivore nematode to fungivore plus bacterivore nematode, and the nematode diversity indices all decreased with the combination treatment. Overall, the results of this study demonstrate that combined application of HDZ-9-47 with biofumigation was a useful and effective approach to suppress M. incognita by manipulating soil microbial communities in field.

ORGANIC FERTILIZER AMENDMENTS REDUCE DISEASE SEVERITY OF Phytophthora palmivora ROOT ROT OF DUKU (Lansium domesticum) SEEDLING

Phytophthora palmivora, is a deadly pathogen of duku, causing serious problem in the main production area, especially in Jambi Province, Indonesia. The pathogen can infect duku plant in all stage of growth including seedlings. Organic amended media might become a potential alternative option for this disease management. These studies were performed in soil media containing organic fertilizer of 0%, 10%, 20%, 30% (v/v), served as treatment, and subjected to completely randomized design with 5 replications. This research found that incorporating 20% of organic fertilizer into media was able to lower disease severity by 23%. The ability of organic fertilizer to increase media bacterial and maintain fungal density and increase chemicals of C-org, P, K, Ca, Mg and Zn played important roles in reducing disease development.

KEPADATAN JAMUR MIKORIZA VESIKULAR ARBUSKULAR (MVA) DI KAWASAN HUTAN MANGROVE DESA PENITI KABUPATEN MEMPAWAH KALIMANTAN BARAT

Mycorrhizal fungi are fungi that are associated with higher levels of plants and are very important in plant growth. Mycorrhizal fungi can be found most of the land, one of which is in the mangrove forest. This study was conducted to determine the type of fungus and the percentage of infections in plant roots and fungal density of VAM found in the Mangrove Forest area at Mempawah Regency, West Kalimantan. This research was conducted at the Microbiology Laboratory of the Department of Biology, Faculty of Mathematics and Natural Sciences. Analysis of soil chemical content was carried out in the Laboratory of Chemical and Soil Fertility, Faculty of Agriculture, Tanjungpura University. Isolation of spores was carried out by wet filter method and continued with centrifugation. The results indicated that the spores found consisted of 3 genera were Glomus, Gigaspora and Paraglomus. The percentage of root infections by mycorrhizal fungi was classified as low at 10.65%, and density of VAM fungus spores in Parit Tanjung as many 13 spores, Kasim as many 10 spores, Sungai Burung as many 59 spores and Tanjung as many 33 spores.

Large, high-severity burn patches limit fungal recovery 13 years after wildfire in a ponderosa pine forest

Over the past three decades, wildfires in southwestern US ponderosa pine (Pinus ponderosa Lawson & C. Lawson) forests have increased in size and severity. These wildfires can remove large, contiguous patches of mature forests, alter dominant plant communities and increase woody debris, potentially altering fungal community composition. Additionally, post-fire conditions may shift dominant fungal functional groups from plant-symbiotic ectomycorrhizal (EM) fungi to more decomposer saprotrophic fungi. We investigated the long-term (13 years post-wildfire) effect of fire severity on 1) fungal sporocarp density, functional groups and community composition and 2) EM colonization and community composition from naturally regenerating ponderosa pine seedlings on the Pumpkin Fire that burned in 2000 in Arizona, USA. Plots were located in four burn severity classes: unburned, moderate-severity, and two high-severity (defined as 100% tree mortality) classes, either adjacent to residual live forest edges (edge plots), or >200 m from any residual live trees (interior plots). We found that high-severity burn plots had a unique sporocarp community composition, and a shift in dominant sporocarp functional groups, with 5–13 times lower EM sporocarp densities, and 4–7 times lower EM sporocarp species richness compared to unburned and moderate-severity plots. In contrast, saprotrophic sporocarp densities and richness were similar among burn severity classes, even with the large amount of coarse wood in the high-severity burn patches. Regenerating ponderosa pine seedlings had similar EM colonization and richness among severity classes, yet high-severity interior plots had a different community composition and a lower relative abundance of EM species compared to moderate-severity burn plots. Taken together, our results suggest that large patches of high-severity fire have long-term consequences for both EM sporocarp and root tip communities. Because EM fungal species vary in function, the limited species pool available in interior high-severity burn patches may influence pine recovery.

Distribution and genetic diversity of Beauveria species at different soil depths in natural and agricultural ecosystems

This study aimed to analyze vertical distribution and diversity of Beauveria species throughout the soil profile within farmland and forest habitats to obtain an accurate view of Beauveria density and diversity associated with a particular soil layer. The analysis included a total of 72 soil samples collected at four depths: 0–5, 5–10, 10–15, and 15–20 cm. Of the soil samples, 43 (60%) were positive for Beauveria, producing a total of 641 isolates. Of the positive samples, 28 (65%) were from depths of 0–5 and 5–10 cm while only 15 (35%) from depths of 10–15 and 15–20 cm. Further, for the 29 negative samples, 21 (72%) of them were from depths of 10–15 and 15–20 cm. Higher fungal frequency was found in forest habitat, 462 isolates in 21 positive samples (72%), than from farmland, 179 isolates in 22 positive samples (28%). The highest fungal density (577 isolates, 90%) was recorded in the two top layers (0–5 and 5–10 cm) and decreased significantly as the soil depth increased. Only two species B. bassiana and B. pseudobassiana were identified and co-habited along the whole soil profile. Beauveria pseudobassiana was more strongly affiliated with forest (79%) than farmland (27%) and vice-versa for B. bassiana (21% and 73%, respectively). For both species, the haplotypic diversity varied throughout the soil profile and the highest diversity values were recorded within the soil depths 0–5 and 5–10 cm. This study suggested that the soil band 0–10 cm could be adopted as the standardized depth for soil sampling for ecological studies of Beauveria. It will be important to perform exhaustive soil sampling in different seasons and at different soil depths to validate this hypothesis.

Effects of Disease Resistant Genetically Modified Rice on Soil Microbial Community Structure According to Growth Stage

BACKGROUND: This study investigated the effects of rice genetically modified to be resistant against rice blast and rice bacterial blight on the soil microbial community. A comparative analysis of the effects of rice genetically modified rice choline kinase (OsCK1) gene for disease resistance (GM rice) and the Nakdong parental cultivar (non-GM rice) on the soil microbial community at each stage was conducted using rhizosphere soil of the OsCK1 and Nakdong rice. METHODS AND RESULTS: The soil chemistry at each growth stage and the bacterial and fungal population densities were analyzed. Soil DNA was extracted from the samples, and the microbial community structures of the two soils were analyzed by pyrosequencing. No significant differences were observed in the soil chemistry and microbial population density between the two soils. The taxonomic analysis showed that Chloroflexi, Proteobacteria, Firmicutes, Actinobacteria, and Acidobacteria were present in all soils as the major phyla. Although the source tracking analysis per phylogenetic rank revealed that there were differences in the bacteria between the GM and non-GM soil as well as among the cultivation stages, the GM and non-GM soil were grouped according to the growth stages in the UPGMA dendrogram analysis. CONCLUSION: The difference in bacterial distributions between Nakdong and OsCK1 rice soils at each phylogenetic level detected in microbial community analysis by pyrosequencing may be due to the genetic modification done on GM rice or due to heterogeneity of the soil environment. In order to clarify this, it is necessary to analyze changes in root exudates along with the expression of transgene. A more detailed study involving additional multilateral soil analyses is required.

Managing raw materials of vegetable origin increases fungal indoor concentration in food companies.

Fungi in indoor environments is a known cause of disease and food spoilage. However, there is currently no legislation or normativity stablishing limits for fungal densities in correlation with these. Moreover, there is little knowledge of the diversity of fungi in indoor environments for industrial areas and in food-related companies in particular, a study has never been performed to evaluate the concentration and diversity of fungi in this type of places. We evaluated the fungal density of 20 food companies. We sampled 100L of air onto rose bengal-malt extract-agar plates, using an Air Test Omega® sampler. After incubation, CFUs were counted and identified. Penicillium, Cladosporium and Aspergillus were the most commonly isolated genus, with Penicillium being the only genus to be present in every area sampled. Neither the companies' location nor their room temperature influenced the fungal densities significantly, however, companies using vegetable raw materials had a significantly greater concentration of fungi than the rest of the companies. While all concentrations were within previously suggested levels from a health-related point of view, more information is needed that correlates fungal concentration with food spoilage in order to suggest a range of concentrations focused for food companies' product preservation.

PAS stain based histological classification and severity grading of toenail onychomycosis.

Onychomycosis is a common world-wide health issue. Accurate detection is essential for treatment. Multiple studies have shown that PAS-stain based histological visualization of fungal elements is superior to either direct microscopy with 20% potassium hydroxide, or fungal culture. However, PAS stain based histological classification and severity grading of onychomycosis are lacking in the literature. Here we reported a fungal detection rate of 47.87% based on an analysis of 13,805 toenails processed for H&E and PAS stains over a three year period. Based on the analysis of fungal density, distribution and infiltrating depth level in 858 PAS-positive toenails, we created a novel PAS stain based histological classification system to classify onychomycosis as occult onychomycosis (OO), focal or diffuse subungual onychomycosis (FSO or DSO), focal or diffuse plate onychomycosis (FPO or DPO), focal or diffuse subungual and plate onychomycosis (FSPO or DSPO) and superficial onychomycosis (SO). The severities of OO, FSO and FPO were graded as mild, DSO and DPO as moderate, FSPO and DSPO as severe infections, which revealed that more than 75% PAS positive toenails were severe infections. Evaluation of 97 paired toenails biopsied pre- and post-treatment from 47 patients demonstrated that the severity of infection was significantly reduced from severe to mild and moderate levels. These data indicate that the current histological classification evaluates not only the severity of the fungal infection but also the response to treatment. We further propose a guideline for treatment of onychomycosis based on the histological classification and severity.

Aphids Influence Soil Fungal Communities in Conventional Agricultural Systems.

Arbuscular mycorrhizal fungi (AMF) form symbioses with the roots of most plant species, including cereals. AMF can increase the uptake of nutrients including nitrogen (N) and phosphorus (P), and of silicon (Si) as well as increase host resistance to various stresses. Plants can simultaneously interact with above-ground insect herbivores such as aphids, which can alter the proportion of plant roots colonized by AMF. However, it is unknown if aphids impact the structure of AMF communities colonizing plants or the extent of the extraradical mycelium produced in the soil, both of which can influence the defensive and nutritional benefit a plant derives from the symbiosis. This study investigated the effect of aphids on the plant-AMF interaction in a conventionally managed agricultural system. As plants also interact with other soil fungi, the non-AMF fungal community was also investigated. We hypothesized that aphids would depress plant growth, and reduce intraradical AMF colonization, soil fungal hyphal density and the diversity of AM and non-AM fungal communities. To test the effects of aphids, field plots of barley enclosed with insect proof cages were inoculated with Sitobion avenae or remained uninoculated. AMF specific and total fungal amplicon sequencing assessed root fungal communities 46 days after aphid addition. Aphids did not impact above-ground plant biomass, but did increase the grain N:P ratio. Whilst aphid presence had no impact on AMF intraradical colonization, soil fungal hyphal length density, or AMF community characteristics, there was a trend for the aphid treatment to increase vesicle numbers and the relative abundance of the AMF family Gigasporaceae. Contrary to expectations, the aphid treatment also increased the evenness of the total fungal community. This suggests that aphids can influence soil communities in conventional arable systems, a result that could have implications for multitrophic feedback loops between crop pests and soil organisms across the above-below-ground interface.

Rhizosphere fungal community, soil physicochemical properties, understorey vegetation and their relationship during post-coal mining reclamation in East Kalimantan, Indonesia

Abstract. Sudrajat, Widhayasa B, Rusdiansyah, Susanto D. 2019. Rhizosphere fungal community, soil physicochemical properties, understorey vegetation and their relationship during post-coal mining reclamation in East Kalimantan, Indonesia. Biodiversitas 20: 1953-1962. The objective of this study was to evaluate the composition of fungal community in rhizosphere, understorey vegetation and soil physicochemical properties post-coal mining reclamation. Soil sampling was conducted using a series of reclamation stages plots (undisturbed, disturbed, two, nine, twelves and sixteen years of reclamation) with drill ground at a depth of 0-30 cm. On each plot, five-point drilling was conducted; soil samples were composited; and their physicochemical properties including soil pH, organic carbon, total N, available P, available K, Ca, Mg, Fe, Mn, and S content were analyzed. Rhizosphere microfungi were isolated by using serial dilution and plated on potato dextrose agar added with Streptomycin. Identification and characterization of soil microfungi were done with the help of accessible manuals of fungi. The results showed that fungal genera at rhizosphere during post-coal mining reclamation were Aspergillus, Penicillium, Cephalosporium, Gliocladium, Humicola, Trichoderma, and Paecilomyces. Aspergillus was dominant comprising 74% of the total isolates. The fungal density in the undisturbed soil and the post-coal mining reclamation soil were higher than in the disturbed soil. The fungal rhizosphere groups isolated were saprophytic fungi that were present in a high relative density. In addition, the results showed that fungal rhizosphere was negatively correlated with soil pH and organic carbon. On the other hand, fungal rhizosphere was positively correlated with total N, available P, and available K. It can be concluded that the time period of post-coal mining reclamation, vegetation, and soil physicochemical profoundly determined the soil fungal community.

Effect of drought and season on arbuscular mycorrhizal fungi in a subtropical secondary forest

Arbuscular mycorrhizal (AM) fungi in both soil and roots were examined in May (summer) and December (winter) under a 4-y drought experiment in a Chinese subtropical secondary forest. Drought significantly decreased AM fungal extra-radical hyphal density, spore density, and root colonization rate in both seasons. These AM parameters were significantly higher in summer than in winter in the control treatment, but only AM fungal extra-radical hyphal density exhibited the same seasonal trend in the drought treatment. In total, 45 AM fungal operational taxonomic units (OTUs) were obtained at a 97% sequence similarity level using Illumina sequencing of 18S rDNA. Drought and season had no significant effects on AM fungal OTU richness in soil and roots. AM fungal community composition in soil and roots was significantly affected by season but not by drought. This finding enhances our understanding of the response of AM fungi to global climate change in subtropical forest ecosystems. • AM fungal abundance was decreased by drought in both seasons. • AM fungal richness was not affected by drought or season. • AM fungal community composition was influenced by season but not by drought.