Arbuscular Mycorrhizal Fungi Species Composition Research Articles

Impacts of Managed Vegetation Restoration on Arbuscular Mycorrhizal Fungi and Diazotrophs in Karst Ecosystems.

The crucial functional arbuscular mycorrhizal fungi (AMF) and diazotrophs play pivotal roles in nutrient cycling during vegetation restoration. However, the impact of managed vegetation restoration strategies on AMF and diazotroph communities remains unclear. In this study, we investigated the community structure and diversity of AMF and diazotrophs in a karst region undergoing managed vegetation restoration from cropland. Soil samples were collected from soils under three vegetation restoration strategies, plantation forest (PF), forage grass (FG), and a mixture of plantation forest and forage grass (FF), along with a control for cropland rotation (CR). The diversity of both AMF and diazotrophs was impacted by managed vegetation restoration. Specifically, the AMF Shannon index was higher in CR and PF compared to FF. Conversely, diazotroph richness was lower in CR, PF, and FG than in FF. Furthermore, both AMF and diazotroph community compositions differed between CR and FF. The relative abundance of AMF taxa, such as Glomus, was lower in FF compared to the other three land-use types, while Racocetra showed the opposite trend. Among diazotroph taxa, the relative abundance of Anabaena, Nostoc, and Rhizobium was higher in FF than in CR. Soil properties such as total potassium, available potassium, pH, and total nitrogen were identified as the main factors influencing AMF and diazotroph diversity. These findings suggest that AMF and diazotroph communities were more sensitive to FF rather than PF and FG after managed vegetation restoration from cropland, despite similar levels of soil nutrients among PF, FG, and FF. Consequently, the integration of diverse economic tree species and forage grasses in mixed plantations notably altered the diversity and species composition of AMF and diazotrophs, primarily through the promotion of biocrust formation and root establishment.

Arbuscular Mycorrhizal Fungi as an Important Factor Enabling the Adaptation of Anthyllis vulneraria L. to Zn-Pb-Polluted Tailings.

The old Zn-Pb-contaminated (calamine) tailings in southern Poland are spontaneously colonized by metal-tolerant Anthyllis vulneraria L. (Fabaceae), which can form simultaneously symbiotic association with nitrogen-fixing rhizobia and phosphorus-acquiring arbuscular mycorrhizal fungi (AMF). So far, fungal colonization and the AMF diversity of calamine-inhabiting legumes have been poorly studied. Thus, we determined AMF spore density in the substratum and the mycorrhizal status of nodulated A. vulneraria plants occurring on calamine tailings (M) and on a reference non-metallicolous (NM) site. The results indicate the presence of the Arum-type of arbuscular mycorrhiza in the roots of both Anthyllis ecotypes. Despite the presence of AM fungi in M plant roots, the dark septate endophyte (DSE) fungi (hyphae and microsclerotia) were occasionally also detected. Metal ions were accumulated mainly in the nodules and intraradical fungal structures rather than thick plant cell walls. Mycorrhization parameters (frequency of mycorrhization and intensity of root cortex colonization) for M plants were markedly higher and differed in a statistically significant manner from the parameters for NM plants. Heavy metal excess had no negative effect on the number of AMF spores, the amounts of glomalin-related soil proteins and AMF species composition. Molecular identification of AMF using PCR-DGGE analysis based on the 18S rDNA ribosomal gene by nested-PCR with primers AM1/NS31 and NS31-GC/Glo1 revealed similar genera/species of AMF in the roots of both Anthyllis ecotypes: Rhizophagus sp., R. fasciculatus, and R. iranicus. The results of this work indicate the presence of unique fungal symbionts, which may enhance A. vulneraria tolerance to heavy metal stress and plant adaptation to extreme conditions on calamine tailings.

Do commercial arbuscular mycorrhizal inoculants contain the species that they claim?

The use of arbuscular mycorrhizal (AM) fungal inoculants as a means to promote plant growth is gaining momentum worldwide. Although there is an increasing number of commercial products available for various applications, the quality of these remains uncertain. We determined the AM fungal species composition in eleven inoculants from four producers by using DNA metabarcoding and compared them to the AM fungal species declared on the product labels. Our DNA metabarcoding of the inoculants revealed a concerning discrepancy between the declared and detected AM fungal species compositions of the products. While nine products contained at least one declared species, two did not contain any matching species and all inoculants but one contained additional species not declared on the product label. These findings highlight the need for better guidelines and industry standards to ensure consumer protection in the AM fungal inoculum market. Additionally, we call for caution when using commercial AM fungal inoculants in scientific experiments without confirmatory information about their species composition.

The effects of fine roots and arbuscular mycorrhizal fungi on soil macropores

Soil macropores are crucial to assess soil stability and control erosion as an essential component of soil structure. The variations in soil macropores with vegetation succession remain largely unclear, and the regulatory mechanism is still poorly understood. Plant fine roots and arbuscular mycorrhizal fungi (AMF) have been supposed to be dominant determinants of soil structure, but their separate effects on soil macropores remain underappreciated, let alone the effects of their interactions. This study used quantified imaging techniques to explore the effects of plant fine roots and AMF on soil macropores along a 55-year vegetation restoration chronosequence on the Loess Plateau. We found that soil macropore properties, such as macroporosity, connectivity, fractal dimension, and tortuosity, were all significantly improved with vegetation succession. Fine root density properties significantly increased, whereas morphological properties decreased along the restoration chronosequence with a shift to a conservative root resource usage strategy. Furthermore, duration of vegetation succession had a positive effect on AMF community structure and mediated the root chemical properties indirectly. Plant fine roots affected macropores directly with the positive effects of root density properties, whereas the morphological properties and chemical properties had negative effects. By comparison, the influence of the AMF community structure (i.e., AMF species composition) on macropore features was indirectly mediated through root chemical properties. Overall, this study investigated how plant fine roots and AMF separately and/or jointly affected soil macropores via direct and indirect mechanisms. Thus, this study may greatly contribute to restoration by assisting vegetation configuration to improve soil structure and enhancing the ecological function of afforestation.

Effect ofElymus nutans on the assemblage of arbuscular mycorrhizal fungal communities enhanced by soil available nitrogen in the restoration succession of revegetated grassland on theQinghai‐TibetanPlateau

AbstractThe succession of arbuscular mycorrhizal fungi (AMF) communities during ecosystem development has received widespread attention, but the ecological mechanism that drives the succession of AMF communities during the restoration process in alpine meadow ecosystems remains unclear. Here, we treated ‘Black Beach’ (severely degraded alpine meadow) as the baseline for restoration (0 year), and selected the revegetated grassland ofElymus nutanswith different planting times (3, 7, 10, and 14 years) to analyze the species composition of the AMF community in mixed roots (at the whole‐plant‐community scale) and inE. nutansroots (at the single‐plant‐species scale). A total of 46 AMF phylotypes (mixed roots: 44;E. nutansroots: 46) were identified in both root systems, predominantly belonging to Glomeraceae. AMF species richness showed a single‐peak curve change across the restoration time and reached its peak at 3 years in both root systems. In mixed roots, the soil available nitrogen not only directly changed the AMF species composition but also indirectly changed the AMF species composition through plant richness. In theE. nutansroots, only the soil available nitrogen drove changes in AMF species composition through changes in plant richness. Our results indicate thatE. nutans, a key species in the restoration process of revegetated grassland, can enhance its regulation to assemble the AMF community through soil available nitrogen at the two research scales, suggesting that the scientific management of soil nitrogen availability during restoration succession could strengthen the mutual symbiosis of ‘plant‐AMF,’ thereby retarding the occurrence of secondary degradation of revegetated grassland.

Biodiversity of arbuscular mycorrhizal fungi in plant roots and rhizosphere soil from different arid land environment of Qatar.

Recently more attention has been observed toward the role of arbuscular mycorrhizal fungi (AMF) in plant growth. Qatar belongs to the Arabian Gulf region with hot and dry climatic conditions. The study aims to investigate the species composition and abundance of AMF in Qatar, rhizosphere soil samples, and roots of plants from 12 families and 8 different locations. The AMF were identified based on the sequencing of the polymerase chain reaction (PCR) product of the amplified conserved ITS region. The reported AMF infection rate was found to vary with location and plant species. Tamarix aphylla recorded the highest AMF infection rate (100%), followed by Blepharis ciliaris (98%) and Sporobolus ioclados (92%). AMF spore counts ranged from 29.3 spores in Blepharis ciliaris to 643 spores/100 g soil in Fagonia indica. No correlation was detected between colonization rate and spore counts. While all AMF identified at species levels were reported in other regions, new species are still expected since some were identified only at higher taxonomic levels. Claroideoglomus drummondii and Rhizophagus irregularis were the most widespread while Claroideoglomus claroideum and Diversispora aurantia were the least present. Our results fill the gap of knowledge of AMF in the region and opens new research toward its future applications for sustainable agriculture.

Wildfire does not affect spore abundance, species richness, and inoculum potential of arbuscular mycorrhizal fungi (Glomeromycota) in ferruginous Canga ecosystems

Canga ecosystems develop over superficial iron crusts with shallow and nutrient-poor soils. Under these conditions, arbuscular mycorrhizal fungi (AMF) play an important role in helping plants to overcome abiotic and biotic stresses. Canga can suffer periodic burning and yet it is unknown what the impacts of fire are to AMF communities. We aimed to compare AMF in Canga areas affected by burning (BC) with those with no previous history of burning (NC). We compared AMF species composition, spore numbers, species richness, and mycorrhizal inoculum potential. The total number of spores, AMF species richness and mycorrhizal colonization measured in the infectivity bioassay were not significantly different between areas. A total of 23 species in 10 genera were recovered, with most species belonging to Gigasporaceae and Acaulosporaceae. BC and NC shared 52 % of AMF species. Gigaspora albida, Gigaspora gigantea, and Dentiscutata heterogama sporulated exclusively in trap cultures. We concluded that AMF spore communities were not affected by burning in Canga soils as measured by spore abundance, species richness and infectivity. Our data contribute to the inventory of soil biodiversity associated with Canga, a high biodiverse and threatened Brazilian ecosystem.

Fungal root colonization and arbuscular mycorrhizal fungi diversity in soils of grasslands with different mowing intensities

Grasslands are among the most dynamic and threatened plant communities, largely due to their dependence on management that has changed in recent decades. The intensity of human-induced disturbances (primarily removal of plant biomass by various methods) has decreased, leading to changes in plant species composition and declines in plant diversity in these communities. So far, no studies have shown how mowing affects fungal communities in both roots and soils and their relation with plant community parameters and soil chemical properties in different grassland types. We thus compared the impact of mowing intensity (low, moderate, high) on root colonization by common root-inhabiting fungi, namely arbuscular mycorrhizal fungi (AMF), dark septate endophytes (DSE), and Olpidium spp., as well as on AMF spore number, species richness and composition in soils for three seasons (spring, summer, autumn), in grasslands differing in soil moisture (wet, moderately wet, and dry). Mowing intensity had no effect on the fungal root colonization. The number of AMF spores and species, and AMF species composition did not differ between types of management as well. However, most of the fungal parameters in roots and soils varied across the types of grassland and/or seasons. Our results suggest that AMF, DSE, and Olpidium spp. colonization of plants as well as AMF diversity in soils in the studied grasslands are resilient to the mowing disturbance. This may be due to the low impact of the management on plant species richness and soil chemical properties, as well as the adaptation of these fungal communities to recurrent human-induced disturbances in semi-natural habitats.

Herbivory and Soil Water Availability Induce Changes in Arbuscular Mycorrhizal Fungal Abundance and Composition.

We tested the prediction that abundance and composition of arbuscular mycorrhizal fungi (AMF) in Ipomopsis aggregata roots and soils are influenced by ungulate herbivory and drought conditions by examining the effects in a field setting over two years. We used a multi-metric approach to quantify AMF root colonization, AMF reproduction, and AMF community composition in roots and soils. We incorporated complimentary community characterization assays by morphologically identifying spores from trap cultures and the use of terminal restriction fragment length polymorphism (T-RFLP) fingerprinting. Herbivory caused a twofold increase in spore production, an increase in AMF taxa diversity in roots, and a shift in AMF species composition in rhizosphere soils. The impact of herbivory was dependent on water availability, which differed in the two contrasting years. This study demonstrates that both soil water availability and herbivory shape arbuscular mycorrhizal fungi communities. The changes to mycorrhizal communities may help in understanding mycorrhizal function in changing climates.

The impact of beech and riparian forest herbaceous plant species with contrasting traits on arbuscular mycorrhizal fungi abundance and diversity

The impact of forest herbaceous plant species identity on arbuscular mycorrhizal fungi (AMF) communities in relation to vegetation and soil chemical properties has rarely been studied in temperate forests. We thus compared abundance and diversity of AMF in two deciduous forests, in the plots with herbaceous plant species of contrasting traits (morphology, phenology, reproduction, and ecology), including Allium ursinum and Dentaria enneaphyllos in a beech forest, as well as Aegopodium podagraria and Ficaria verna in a riparian forest. Plots with a mix of herbaceous plant species and bare soil were also studied. We found low values of AMF root colonisation degrees in both forests. In total, the spores of only 13 AMF species were detected; 12 species occurred in the riparian forest, whereas 6 were found in the beech forest. AMF species composition differed between forest types. Higher AMF root colonisation degrees and soil concentrations of PLFA 16:1ω5 AMF structural lipid marker were found in the riparian forest. There were no differences between the plots in AMF abundance and species richness in both forest soils. With regard to environmental variables, the number of arbuscular mycorrhizal (AM) tree species, plant cover, moisture, the concentrations of C, Ca, K, Mg, and N had, in general, a positive effect on AMF abundance in soils. We showed that despite AMF ubiquity, these fungi can be present at low densities in some habitats, such as beech and riparian forests. Higher AMF abundance and diversity in the riparian forest were probably related to larger numbers of AM tree and herbaceous plant species in this forest. Although the herbaceous plant species had contrasting traits, they had little effect on AMF abundance and diversity.

Diversity and species composition of arbuscular mycorrhizal fungi across maize fields in the southern part of Belgium.

Arbuscular mycorrhizal fungi (AMF) are key actors among soil microbial inhabitants, forming beneficial associations with most horticultural plants and crops (e.g., maize). For maize, the world most cultivated cereal, data on AMF species diversity in fields is sparse and even totally nonexistent in the southern part of Belgium where maize represents 8% of the cultivated area. In the present study, 14 maize fields in South Belgium under conventional, conversion, or organic management were analyzed for AMF diversity and species composition using 454 pyrosequencing. A large part (54%) of the 49 AMF species observed were unknown or have not been described in the literature. AMF diversity highly varied among fields, with the number of species ranging between 1 and 37 according to the field. A statistically significant effect of management was measured on AMF diversity, with the highest Hill index values (diversity and richness) under the organic management system compared with conventional management or conversion. Our results suggest a positive effects of organic management on AMF diversity in maize. They also highlight the rather high diversity or richness of AMF and the large portion of sequences not yet ascribed to species, thereby emphasizing a need to intensify AMF identification in cropping systems.

Ignored diversity of arbuscular mycorrhizal fungi in co-occurring mycotrophic and non-mycotrophic plants.

Arbuscular mycorrhizal fungi (AMF) colonization in roots of putative non-mycotrophic species has been known for decades, but our knowledge of AMF community structure in non-mycotrophic plants is limited. Here, we compared AMF species composition and diversity in roots of co-occurring mycotrophic and putative non-mycotrophic herbs in two wetlands. A SSU-ITS-LSU fragment in AMF rDNA was amplified, cloned and sequenced, and used to characterize the AMF community in the roots of 16 putative non-mycotrophic and 18 mycotrophic herbs. The results showed that AMF hyphae and vesicles, but not arbuscules, were commonly present in putative non-mycotrophic plants. A total of 971 AMF sequences were obtained, and these were finally assigned to 28 operational taxonomic units (OTUs). At both sites, AMF taxon richness and Hill number based on Shannon's index in the putative non-mycotrophic herbs were similar to those for mycotrophic plants, but AMF community composition between mycotrophic and non-mycotrophic plants was significantly different. Ten AMF OTUs were uniquely detected in the putative non-mycotrophic species, and two were identified as the AMF indicators in non-mycotrophic plants. These results implied that non-mycotrophic plants may harbor a potential source of AMF diversity previously ignored which should be included in our understanding of diversity, distribution pattern, and ecological significance of root-colonizing AMF. As the first direct comparison of AMF diversity and species composition between mycotrophic and putative non-mycotrophic species in wetlands, our study has important implications for the understanding of AMF distribution patterns.

Changes in Arbuscular Mycorrhizal Fungal Community Structure in Soybean Rhizosphere Soil Assessed at Different Growth Stages of Soybean

Arbuscular mycorrhizal fungi (AMF) is the most common type of AMF association colonizing the rhizosphere of soybean [Glycine max (L.) Merrill] plants. However, the extent of AMF formation, AMF species composition and diversity at different stages of soybean penology have not yet studied. The current study was aimed to determine AMF species community composition, species distribution and its affinity in the rhizosphere soil of soybean at the different growth stages of soybean. Root and rhizosphere soil samples were collected at different growth stage pre-sowing, nodulation, maturation and harvesting stage from soybean (cultivar JS-335) and were analysed for AMF root colonization, spore diversity, species richness, and relative occurrence of AMF species. The AMF species principally contributing to the crop growth stage was also examined through principal component analysis (PCA). The extent of root length colonized by native AMF (mainly formed arbuscules) in soybean roots was higher at maturation (79.76%) and lowest (25.33%) at nodulation stages, whereas the spore density showed opposite trend. Irrespective of growth stages, a total of 40 AMF morphotypes were observed from which species, viz. Glomus aggregatum, Rhizophagus fasciculatum, Glomus coronatum, Glomus etunicatum, Glomus sp (76.92%), were found to be the most frequent and abundant species followed by species of Acaulospora (12.82%) and Gigaspora (10.25%). The Shannon–Weaver index was the range of 3.22, whereas Simpson’s index was 0.95, which indicates the higher diversity of AMF at pre-sowing. The PCA explains the maximum contribution of all AMF species observed at pre-sowing followed by harvesting concludes that AMF diversity and colonization pattern are greatly affected with the soybean phenological growth stages where rhizosphere was found to be mainly dominated by Glomus morphotypes than the Acaulospora and Gigaspora; hence these can be selected for further exploitation in soybean.

Composition and diversity of arbuscular mycorrhizal fungi spore associated with different land-use types in tropical gold mine

Understanding the composition and diversity of arbuscular mycorrhizal fungi (AMF) is imperative for potentially enhancing their ecological role in different terrestrial ecosystems. Land use can have substantial effects on AMF species composition and diversity, but such effects have been explored less in tropical landscapes. In this study, we assessed the effects of disturbances on AMF species richness, observed the potential development of AMF types to produce mycorrhizal biofertilizer bioinoculants. This study was conducted identifying and selecting AMFs was for the purpose of managing post-mining land in Bombana District, Southeast Sulawesi, Indonesia. AMF spores collected from the field and trap culture were directly isolated and morphologically identified. A total of 15 AMF species were identified, including 11 species from field samples and 9 species from trap cultures. We noted that five AMF species were unique to field conditions and 5 AMF species were uniquely isolated from trap culture. It appears that Glomeraceae family contributed the highest number of species in all land-use types. Glomus sp. 1 was the most frequent species found in all land-use types. The Simpson’s index, Shannon index and evenness ranged from 1.60 ± 0.51 to 2.40 ± 0.40; 0.41 ± 0.17 to 0.62 ± 0.17; 0.25 ± 0.10 to 0.39 ± 0.11, respectively. In this study, we found three new records of AMF species including Entrophospora colombiana , Sclerocystis microcarpa and Glomus coronatum for Indonesia, i.e. from this study, it is clear that different land-use types affected AMF spore composition and species diversity. All AMF species found in this study were then applied to the land to improve land quality.

Native forests but not agroforestry systems preserve arbuscular mycorrhizal fungal species richness in southern Ethiopia

The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.

Changes in the mycorrhizal fungal community in host roots over five host generations under low and high phosphorus conditions

We tested whether arbuscular mycorrhizal fungal (AMF) community might shift as host plant generations advance under a low phosphorus (P) soil. Two greenhouse experiments were conducted using Medicago truncatula as the host plant, six AMF species, and two soil P levels. Experiment 1 assessed changes in AMF composition in roots and soil during five generations of host plant grown in low-P (5.7 mg kg−1) and high-P soil (24.0 mg kg−1). Experiment 2 tested the effects of single AMF species on host plant growth in low-P and high-P soil. Experiment 1 showed that AMF species composition at the OTU level in roots and soil significantly changed as host generations advanced, and that the pattern of change differed in low-P vs. high-P soil. In low-P soil, the dominant OTU in both roots and soil shifted from OTU-50 (Glomus tortuosum) to OTU-49 (Funneliformis geosporum) as host generations advanced. In high-P soil, the AMF community in roots and soil was dominated by OTU-50 in first two generations but OTU-49 and OTU-50 were co-dominant in the last three generations. Experiment 2 showed that mycorrhizal dependency indices based on plant biomass and P content in plant biomass, and spore numbers were higher in host plants with F. geosporum than other AMF fungal treatments in low-P soil. As the host M. truncatula grew in a low-P soil over five generations, AMF community in root and soil shifted to a composition with F. geosporum as dominant species who was effective in foraging for P.

How do monocultures of fourteen forest tree species affect arbuscular mycorrhizal fungi abundance and species richness and composition in soil?

Despite the presence of arbuscular mycorrhizal fungi (AMF) in temperate forests, knowledge concerning their diversity and interactions with plants is still insufficient. Therefore, we studied the impact of overstorey species identity on AMF abundance and species richness and composition in relation to herbaceous plant cover and soil chemical properties. The effects of 14 tree species grown for 48 years in monospecific plots in the Siemianice Experimental Forest (western Poland) were compared, including the following groupings: deciduous vs coniferous; native to Poland/Europe vs alien; forming vs not forming arbuscular mycorrhizas (AM). Coniferous tree plots were characterised by lower pH values, plots with deciduous trees by higher concentrations of total Ca and exchangeable forms of Ca, K and Mg. AMF abundance in soils and roots increased along with increasing soil alkalinity and macronutrient levels. Concentrations of the PLFA 16:1ω5 AMF hyphal biomass marker were higher in the soils of deciduous and AM-type tree species than those of coniferous and non-AM types. In addition, concentrations of the NLFA 16:1ω5 AMF spore biomass marker were higher in the soils of deciduous tree species. No significant differences were found between groups of native and alien tree species. AMF spore and species numbers were low in comparison to other unforested ecosystems, averaging 77.5 and 1.2 per 50 g of soils, respectively. The presence of 8 AMF species, both widespread (e.g. Funneliformis constrictus) and rare (Acaulospora cavernata) was revealed. Significant divergence in AMF species composition was noted between plots of deciduous and coniferous species. Our study showed that tree species identity, considered as a single factor, has only a slight impact on determining AMF community characteristics. The disparity between AMF community characteristics results from the effects of several factors, as pH and element concentrations in soils, acting within tree species groups.

Soil microbiological properties and enzyme activity in agroforestry systems compared with monoculture, natural regeneration, and native Caatinga

The objective of this study was to evaluate the influence of agroforestry systems of different ages (AFS1: one-year old; AFS5: five-years old) on the biological attributes of soil; the following systems were used for comparison: a slash-and-burn (SBF) farming area, Caatinga which has been undergoing regeneration for 6 years (CaR6), and native Caatinga (NCa) in Brazil. Enzyme activity, abundance and composition of arbuscular mycorrhizal fungi (AMF), and production of glomalin-related soil proteins (GRSP) were evaluated at soil depths of 0–0.05 m. AMF species composition in the AFS was more similar to that in the NCa than in the SBF and CaR6 systems. In the rainy season, sporulation was most abundant in the AFS-1, CaR6, and SBF systems, whereas GRSP concentrations were highest in the AFS5 during the dry season. Acid phosphatase and arylsulfatase enzyme activity was lower in the AFS1 soils than in the NCa and SBF soils (rainy period), and levels of β-glucosidase and fluorescein diacetate hydrolysis in the AFS were equal to or higher than those in the NCa in the dry season but lower in the rainy season. AFS thus appear to promote the maintenance of soil biological quality, and may be more sustainable than SBF farming systems in the Brazilian Caatinga over the long term.

Monitoring of fungal root colonisation, arbuscular mycorrhizal fungi diversity and soil microbial processes to assess the success of ecosystem translocation.

To compensate for an airport expansion, including construction on valuable wet meadows of a Natura 2000 system, 1.3 ha of turf, cut into blocks, were transferred to artificial basins in a habitat garden. To evaluate the impact of translocation on this ecosystem, and thus the success of its preservation, we monitored fungal root colonisation of Molinia caerulea, the diagnostic plant species for wet meadows, along with arbuscular mycorrhizal fungi (AMF) species richness and composition in soils and soil microbial processes for three seasons: prior to the transfer (2013) and the two following years (2014-15). We observed few changes in the fungal colonisation of M. caerulea, suggesting that the fungal associations of this species were unaffected. The number of AMF species declined directly after the translocation; however, in 2015, an increased number of species was recorded. There were no differences in AMF species composition, nor did soil basal respiration rate, substrate-induced respiration (SIR), or substrate-active biomass (Cmic) change over the years. Only metabolic coefficient (qCO2) decreased after the transfer. The small number of effects in fungal root colonisation, AMF diversity, and microbial processes following the translocation of the ecosystem prove its success. This can be attributed to the deep turf translocation that kept the relevant microbial communities almost unaffected.

Spore diversity of arbuscular mycorrhizal fungi in human‐modified neotropical ecosystems

AbstractNeotropical landscapes are diverse mosaics of ecosystems commonly resulting from different degrees of human intervention. Although easily recognized by their vegetation, the associated soil microbiota including arbuscular mycorrhizal fungi (AMF) is little known. In Mexico, native tropical rainforest and native savannas are rapidly vanishing, remaining in few spots surrounded by human‐made ecosystems. It is unknown, however, how such vegetation types differ in their AMF communities. We compared the spore diversity, spore density and root colonization by AMF in contiguous mosaics of tropical rainforest, savanna and two pine plantations, one managed and the other unmanaged. We detected indicator species associated with tropical rainforest. The savanna displayed the highest values of root colonization of AMF and the lowest spore density. Conversely, the highest spore density and the lowest root colonization rates were found in the tropical rainforest. The two pine plantations showed intermediate values of spore density and colonization between tropical rainforest and the savanna. We did not detect significant seasonal differences (between dry and rainy seasons) in AMF species richness, spore density and root colonization within the vegetation types (except for root colonization in the savanna). Soil cation exchange capacity, phosphorus and nitrogen were negatively associated with AMF spore density and species richness. Our findings suggest that contiguous vegetation types in neotropical landscapes may display significant differences in AMF species composition, spore density and root colonization, and that such differences can be explained in part by soil properties and levels of human intervention.