Arbuscular Mycorrhizal Fungal Composition Research Articles

Impact of Silver Nanoparticles on Arbuscular Mycorrhizal Fungi and Glomalin-Related Soil Proteins in the Rhizosphere of Maize Seedlings

Glomalin-related soil protein (GRSP), an important arbuscular mycorrhizal (AM) fungal by-product, plays a key role in preserving or sequestrating soil organic carbon (C). Silver nanoparticles (AgNPs) have become an emerging contaminant and their impacts on soil ecosystems attract increasing concerns. The dynamics of AM fungi and GRSP could therefore form the basis for an in-depth exploration of the influences of AgNPs on soil ecosystems. This study investigated the effects of AgNPs on mycorrhizal growth and AM fungal communities, as well as the GRSP contents in maize (Zea mays L.) soils, with a pot experiment. The contributions of GRSP to soil organic C and the correlations of GRSP with soil organic C were also evaluated. The results indicated that AgNPs decreased the mycorrhizal colonization, AM fungal biomass, and diversity indices, and strongly shifted the community composition of AM fungi with a reduction in Acaulosporaceae and an enrichment in Glomeraceae. Additionally, AgNPs also decreased the soil’s easily extractable (EE) GRSP and total (T) GRSP contents, resulting in lower contributions of EE-GRSP-C and T-GRSP-C to the soil organic C. Linkage analyses revealed that AM fungal abundances have positive correlations with EE- and T-GRSP, and EE- and T-GRSP also positively correlated with soil organic C, indicating that the negative effects of AgNPs on AM fungal abundances and communities were extended to AM-fungal-associated C processes. Altogether, our study found that AgNPs decreased the AM fungal abundances shaped AM fungal communities, and reduced the soil GRSP content, which might subsequently be unfavorable for soil C storage.

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.

Distinct response patterns of soil micro-eukaryotic communities to early-season and late-season precipitation in a semiarid grassland

Semiarid ecosystems are susceptible to changes in precipitation regimes. However, how soil micro-eukaryote communities in semi-arid ecosystems respond to variations in the seasonal distribution of precipitation remains elusive. A 5-year field experiment was performed to investigate the effect of changed precipitation distributions throughout the growing season on soil micro-eukaryotic communities in the temperate steppe. Early-season precipitation did not significantly affect the biomass of arbuscular mycorrhizal fungi (AMF) nor the composition and structure of AMF and protist communities. Late-season precipitation significantly increased the biomass of AMF while significantly altering the relative abundance of dominant genera in AMF and protist communities. There was a clear difference in the community structure of AMF and protists between the late-season precipitation and natural precipitation. In addition, late-season precipitation decreased the amount of consumer protists but enhanced the abundance of parasitic protists. These results indicate that the impact of precipitation limitations in the middle growing season can be weakened by increased precipitation in the early growing seasons, while an increase in precipitation later in the growing season does not improve the impact of a decrease in precipitation in the middle growing season. Our findings highlight the potential impact of intra-annual changes in precipitation in soil micro-eukaryotic communities in arid and semiarid regions.

A survey on the composition and occurrence frequency of arbuscular mycorrhizal fungi in rhizospheric soils and roots of vegetables grown in Ho Chi Minh city

The study aimed to determine the presence and composition of arbuscular mycorrhizal fungi (AMF) in the rhizospheric soils and roots of vegetable plants (14 species of leafy vegetables) grown in Hoc Mon, Cu Chi, and Binh Chanh districts, Ho Chi Minh city. The results of the isolation of AMF spores based on the wet sieving method showed the presence of AMF in the rhizospheric soils of vegetables with an average spore density of 87.6 spores/50 g of soil. For the symbiotic ratio of AMF to the root tissues, there was no symbiosis in 4 vegetable crops, including amaranth, mustard green, leaf mustard, and bok choy. Still, there was symbiosis in the remaining 10 plants, with an average symbiotic rate of 6.6%. Identification of AMF spores based on the morphological characteristics recorded in all the soil samples appeared spore phenotypes of 5 fungal genera including Glomus, Acaulospora, Gigaspora, Scutellospora, and Sclerocystis. However, 3 morphological types were not yet identified. From the obtained results, two genera, Glomus and Acaulospora, have the highest frequency at 43.9 and 39.6%, respectively.

Greater change in arbuscular mycorrhizal fungal richness as a response to short-term rainfall exclusion across the North American monsoon season

Arid ecosystems around the world are projected to experience reduced and more infrequent precipitation events. The effects of reduced rainfall are well understood for plants and aboveground interactions; however, the effect of rainfall on belowground microbial interactions remains understudied. Here, we illustrate the strength and direction of change that short-term manipulative rainfall exclusion treatments have on the composition and relative abundance of Arbuscular Mycorrhizal (AM) fungal communities throughout the monsoon season in the Sonoran Desert. Additionally, we use these rainfall exclusion treatments to further understand the impact of soil moisture on labile forms of nitrogen and phosphorous in a natural environment. Rainfall exclusion treatments were installed to remove 0% (control), 60% (moderate exclusion), and 80% (high exclusion) of rainfall over a single wet season. AM fungal community composition varied among rainfall treatments and across the monsoon season, where change was dependent on initial conditions within treatments. Phosphorous content was also a strong predictor of AM fungal composition and relative abundance. By the end of the season, the difference in AM fungal richness was influenced by rainfall exclusion, with the greatest positive change in richness in the moderate rainfall exclusion treatments. Lastly, AM fungal community turnover was predicted by rainfall exclusion treatments, where rainfall contributed to greater turnover in the control treatment in comparison to other treatments. This study further illustrates the complex association between soil abiotic factors, how they are influenced by environmental stress, and how in turn cause shifts in AM fungal communities.

Facultative mycorrhization in a fern (Struthiopteris spicant L. Weiss) is bound to light intensity

BackgroundThe establishment of mycorrhizal relationships between a fungus and a plant typically enhances nutrient and water uptake for the latter while securing a carbon source for the fungus. However, under a particular set of environmental conditions, such as low availability of light and abundant nutrients in the soil, the resources invested in the maintenance of the fungi surpass the benefits obtained by the host. In those cases, facultative mycorrhizal plants are capable of surviving without symbiosis. Facultative mycorrhization in ferns has been overlooked until now. The present study measured the response of Struthiopteris spicant L. Weiss, and its root-associated fungi to different levels of light and nutrient availability in terms of growth, mycorrhizal presence, and leaf nutrient content. This fern species exhibits a great tolerance to variable light, nutrient, and pH conditions, and it has been found with and without mycorrhizae. We conducted a greenhouse experiment with 80 specimens of S. spicant and three factors (Light, Phosphorus, and Nitrogen) resulting in eight treatments.ResultsWe found a significant influence of the factor light on fungal community composition, plant biomass, and nutrient accumulation. Departing from a lack of colonization at the initial stage, plants showed a remarkable increment of more than 80% in the arbuscular mycorrhizal fungi (AMF) richness and abundance in their roots when grown under high light conditions, compared with the ones in low light. We also observed an upward trend of C:P and C:N ratios and the above- and belowground biomass production when AMF abundance increased. Furthermore, the compositional analysis of the whole fungal communities associated with S. spicant roots revealed clear differences among low-light and high-light treatments.ConclusionsThis study is the first to investigate the importance of light and nutrient availability in determining fern-AMF relationships. We confirmed that Struthiopteris spicant is a facultative mycorrhizal plant. The composition and diversity of AMF found in the roots of this fern are strongly influenced by light and less by nutrient conditions. Our study shows that ferns respond very sensitively to changes in environmental factors, leading to shifts in the associated mycorrhizal communities.

Different Responses of Arbuscular Mycorrhizal Fungal Community Compositions in the Soil and Roots to Nitrogen Deposition in a Subtropical Cunninghamia lanceolata Plantation in China

Elevated nitrogen (N) deposition may stimulate a plant’s dependency on arbuscular mycorrhizal (AM) fungi in phosphorus (P)-deficient subtropical forests. However, the ecological assembly processes and the responses of AM fungal diversity and community structure to N deposition in both the roots and rhizosphere are still unclear. We collected root and soil samples from a Cunninghamia lanceolata plantation forest after four years of N addition and examined the community structure and assembly of AM fungi. Elevated N deposition decreased the AM fungal community diversity in both rhizosphere soil and roots. Glomeraceae was the dominant family of the AM fungal community in both soil and roots across all N addition treatments, followed by Gigasporaceae and Ambisporaceae. However, N addition induced differential variation in the community composition of AM fungi between soil and roots. For soil AM fungi, N addition decreased the Glomeraceae abundance and increased the Gigasporaceae and Ambisporaceae abundance. In contrast, the root AM fungal community was dominated by Glomeraceae under N addition treatments. Furthermore, N addition increased the deterministic community assembly that acted as an environmental filter for soil AM fungi. In contrast, N addition decreased the importance of determinism, implying that the selection of plants on root AM fungi decreased with increasing N addition. Altogether, our findings suggest that the community structure of AM fungi responds differently to N deposition in the soil and roots in subtropical forests and highlight the important role of soil AM fungi in helping host plants respond to N deposition.

Diversity of Arbuscular Mycorrhizal fungi under different agroforestry practices in the drylands of Southern Ethiopia

The conversion of an agroforestry based agricultural system to a monocropping farming system influences the distribution and composition of arbuscular mycorrhizal fungi (AMF). The aim of this paper was to analyze AMF species diversity, spore density, and root colonization across different agroforestry practices (AFP) in southern Ethiopia. Soil and root samples were collected from homegarden, cropland, woodlot, and trees on soil and water conservation-based AFP. AMF spores were extracted from the soil and species diversity was evaluated using morphological analysis and root colonization from root samples. The AMF spore density, root colonization and composition were significantly different among the AFP (P < 0.05). In this study, 43 AMF morphotypes belonging to eleven genera were found, dominated by Acaulospora (32.56%), followed by Claroideoglomus (18.60%). Home gardens had the highest spore density (7641.5 spore100 g− 1 dry soil) and the lowest was recorded in croplands (683.6 spore100 g− 1 dry soil). Woodlot had the highest root colonization (54.75%), followed by homegarden (48.25%). The highest isolation frequency (63.63%) was recorded for Acaulospora scrobiculata. The distribution of AMF species and diversity were significantly related to soil total nitrogen and organic carbon. The homegarden and woodlot AFP were suitable for soil AMF reserve and conservation.

Increasing diversity gradient in lentil mixtures for intercropping with wheat reveals an increase in lentil biomass with minimal impact on mycorrhizal activity

The management of arbuscular mycorrhizal fungi (AMF) is crucial for sustainable agricultural systems, given its beneficial impacts on soil health and crop productivity. This study aimed to assess the effect of lentil (Lens culinaris Medik.) mixtures for intercropping with durum wheat (Triticum durum Desf.) on mycorrhiza and investigate the role of legume intraspecific diversity in mycorrhizal development and crop biomass production. Since both intraspecific and interspecific diversity (i.e., cultivar mixtures and intercropping) have an effect in shaping soil microbiota in the rhizosphere, we hypothesised that increasing the level of diversification in the system enhances the provision of services (e.g., aboveground biomass accumulation), due to enhanced microbial activity and diversity. Specifically, increasing diversity within lentil cultivar mixtures strengthens the affinity of wheat for mycorrhiza, thereby influencing wheat mycorrhization in wheat-lentil intercrops. To test our hypothesis, we designed three lentil cultivar mixtures with increasing diversity levels using a trait-based approach, drawing from a pool of Italian lentil landraces characterised in a previous study. As an additional factor, we intercropped lentil mixtures with wheat and compared it with sole wheat and sole lentil commercial cultivar. In both experimental years, intercropping lentil mixtures with wheat consistently yielded higher soil mycorrhization levels (46% in 2021 and 52% in 2022) compared to sole wheat cultivation (23% in 2021 and 34 % in 2022). Nevertheless, AMF colonisation in lentil roots was significantly higher in sole crops (55% in 2021 and 70% in 2022, except for the commercial cultivar) compared to intercrops (35% in 2021 and 60% in 2022). This difference could be attributed to the presence of wheat, which might have suppressed the capacity of lentils to establish successful symbiosis with mycorrhiza. On the other hand, AMF colonisation of wheat roots in 2022 was significantly higher (52%) when intercropped with lentils than when cultivated as sole wheat (40%). Concerning biomass production in lentil mixtures in 2022, we observed a positive correlation between lentil biomass and the number of functional groups in the mixtures, both as pure stands (R2 = 0.19, p = 0.06) and intercrops (R2 = 0.29, p = 0.01). Additionally, in 2022, the total biomass of the intercropped system increased with the increase in diversity. Further experiments, incorporating microbial genetic analysis, are necessary to uncover potential associations between functional mixtures and AMF composition.

Higher colonization but lower diversity of root-associated arbuscular mycorrhizal fungi in the topsoil than in deep soil

Arbuscular mycorrhizal fungi (AMF) colonizing plant roots play a pivotal role in maintaining soil nutrient cycling and ecosystem stability, and this role may vary in different habitat environments. However, the influence of soil depth on root AMF colonization, diversity, and the complex interactions among AMF taxa is still not well understood. In this study, we investigated the frequency, intensity, and abundance of root AMF colonization, as well as root AMF diversity, composition, and co-occurrence patterns across three soil depths: 0–20 cm, 20–40 cm, and the soil-rock mixing layer. Soil nutrients (e.g., organic matter, nitrogen, and phosphorus) and root biomass were higher in the 0–20 cm layer than in the soil-rock mixing layer, while soil pH showed an opposite relationship. The higher root biomass in the upper soil layer may enhance root secretions and exudates, thereby promoting root AMF colonization. In contrast, the lower soil nutrient content and higher soil pH observed in the 20–40 cm and soil-rock mixing layers may contribute to greater AMF diversity in the deeper soil layers compared to the topsoil. Although no significant differences were observed in the composition of the root AMF community, specific amplicon sequence variants affiliated with Glomus, Racocetra, and unclassified taxa were more enriched in the 20–40 cm and soil-rock mixing layers compared to the 0–20 cm layer. Network analysis revealed that deep soil, compared to topsoil, enhances interactions among root AMF by intensifying competitive relationships. This suggests that the complex interactions among root AMF taxa within deep soil contribute to the resilience of root AMF in resource-scarce conditions, particularly in the 20–40 cm layer and the soil-rock mixing layer. At the genus level, Glomus, Racocetra, and unclassified taxa emerged as keystone taxa due to their prominent linkage with other root AMF groups. Collectively, the results suggest that higher soil nutrient levels and root biomass can promote root mycorrhizal colonization but suppress AMF diversity and weaken interactions among root AMF taxa in the upper soil layer compared to deeper soil layers. Furthermore, the distinct functions of AMF colonization and diversity at different soil depths should be considered when evaluating vegetation reconstruction in karst ecosystems with varied soil depth distribution.

The Addition of a High Concentration of Phosphorus Reduces the Diversity of Arbuscular Mycorrhizal Fungi in Temperate Agroecosystems

Phosphorus (P) is an essential macronutrient crucial for both plant growth and crop production, playing a pivotal role in agriculture since the early 20th century. The symbiotic relationship between AMF and plants serves as a classic illustration. These fungi play a regulatory role in the growth and development of plants, especially in facilitating the absorption of P and carbon molecules by plants. While there has been a growing body of research on the community assembly of arbuscular mycorrhizal fungi (AMF) in recent decades, our knowledge of the processes governing the coexistence of these AMF communities influenced by P in agroecosystems remains limited. To investigate the impact of various P fertilizers on AMF communities in temperate agroecosystems, this study was conducted using soils sourced from wheat–maize rotation farmland at Henan Agricultural University Yuanyang Base. With the Illumina MiSeq high-throughput sequencing technique, we systematically examined the taxonomic composition of soil AMF at the Yuanyang Base of Henan Agricultural University in a wheat–maize rotation agricultural field. Our primary objective was to unravel the mechanisms behind AMF community assembly and stability under varying P gradient fertilization conditions. Nonmetric Multidimensional Scaling (NMDS) analysis revealed significant differences among AMF communities in field soil subjected to various treatments (p &lt; 0.05). A torus translations test demonstrated positive associations with the three treatments in 36 out of the 51 examined AMF operational taxonomic units (OTUs), making up 70.59% (p &lt; 0.05) of the results. Furthermore, 37.84% (14/37) of the OTUs displayed preferences for the low P concentration treatment, while 34.29% (12/35) and 32.26% (10/31) favored medium and high P concentrations, respectively. An analysis of the Normalized Stochasticity Ratio (NST) and Checkerboard Score (C-score) indicated that in temperate agroecosystems, deterministic processes predominantly governed AMF in all treatment groups, with high P conditions exerting a stronger influence than low or medium P conditions. This study underscores the profound impact of long-term P fertilizer application on AMF community structures within temperate agricultural systems employing wheat–maize rotation. Additionally, it highlights the dominant role played by deterministic processes in shaping the assembly of AMF communities in these temperate agricultural systems that use P fertilizers. These findings emphasize the need for balanced nutrient management, particularly concerning P, to ensure the stability of AMF communities.

Effects of Annual Crop Rotation and Fallow on Soil AMF Community and Aggregate Stability

To investigate the effects of crop rotation and fallow on the community composition of arbuscular mycorrhizal fungi (AMF) and the stability of soil aggregates, AMF community and aggregates were measured using Illumina MiSeq high-throughput sequencing and wet screening methods in red soil of sloping farmland. The AMF community and its relationship with soil factors and aggregate stability were studied under the four treatments of vetch rotation corn (V-C), pea rotation corn (P-C), winter fallow corn (F-C), and annual fallow (F-F). The results showed that the aggregate content of >2 mm, R0.25, and MWD in the F-F, V-C, and P-C treatments were significantly higher than those in F-C (P<0.05), and the aggregate content of <0.25 mm was significantly lower than that of F-C (P<0.05). The ACE, Chao1, and Shannon indexes of the F-F treatment were 29.56%, 35.78%, and 45.55% higher than those of the F-C treatment, respectively. Glomus was the dominant genus of AMF communities under all treatments, whereas Scutellospora showed a significant difference among the treatments (P<0.05). PCoA analysis showed that PC1 and PC2 together explained 29.99% and 22.40% of the difference in the AMF community composition, respectively. The correlation analysis showed that there was a significant negative correlation between Scutellospora and alkaline nitrogen (AN) and organic matter (SOM) (P<0.05), a significant positive correlation between Scutellospora and available potassium (AK) (P<0.05), and a significant positive correlation between Glomus and alkaline nitrogen (P<0.05). RDA analysis showed that AMF diversity (Shannon index) and Scutellospora were significantly and positively correlated with aggregate content >2 mm and 2-1 mm, respectively (P<0.05). Therefore, annual fallow and vetch rotation corn were conducive to improving the stability of soil aggregates and changing the composition of the AMF community. The research results provide a theoretical basis and reference for the annual rotation system to improve soil quality and implement a reasonable crop rotation and fallow pattern in southern China.

Durum wheat-lentil relay intercropping enhances soil mycorrhizal activity but does not alter structure of arbuscular mycorrhizal fungal community within roots

In intercropping systems, crop species select host-adapted microorganisms and influence the associated plant-microbial interactions like in the case of arbuscular mycorrhizal fungi (AMF). Attempts to assess the impact of intercropping on the activity, diversity, and community composition of AMF remain inconclusive, more so in intercropping systems involving traditional Mediterranean crops such as durum wheat and lentils. We carried out field experiments in Central Italy to assess the impact of relay intercropping durum wheat (Triticum durum Desf. cv. Minosse) and lentil (Lens culinaris Medik. cv. Elsa) on soil mycorrhizal inoculum potential (MIP) (2019 and 2020), AMF root colonization (2019, 2020, and 2021), and root AMF diversity and community composition (2020 and 2021), compared to the respective sole crops. Results showed that relay intercropping enhanced lentil grain yield and durum wheat grain protein concentration but marginally reduced durum wheat grain yield and lentil grain protein concentration. In addition, relay intercropping enhanced soil mycorrhizal activity but differentially influenced mycorrhizal root colonization compared to sole cropping. Sequencing analyses generated a total of 234 amplicon sequence variants belonging to Glomeromycota, which were assigned to 31 virtual taxa using the MaarjAM reference database. Glomeraceae and Claroideoglomeraceae were the most abundant taxa but had contrasting abundances in 2020 and 2021. The overall changes in AMF species diversity and community structure were affected by the interaction between crop species and year, and not by intercropping. Claroideoglomus and Septoglomus showed a strong association with lentil roots while Rhizophagus and Paraglomus were associated with durum wheat roots in 2020, affirming host genotype-AMF preferences. The principal component analysis showed that grain protein concentration was associated with selected mycorrhizal parameters such as community richness and AMF root colonization. Further studies on the functional analysis of the different AMF communities selected by the crop genotype and year may reveal the importance of intercropping in maintaining soil functionality and productivity under low-input systems.

PHOSPHORUS FRACTIONS AND ARBUSCULAR MYCORRHIZAL FUNGI AS INFLUENCED BY FOREST CONVERSION IN CENTRAL HIGHLANDS OF KENYA

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Forest conversion to other land use types lead to changes in soil physico-chemical properties and a reduction in soil fertility. Although forest conversion is extensively recognized to alter soil properties, the influence on distribution of soil phosphorus (P) fractions and abundance and diversity of soil biota is not well explored. &lt;strong&gt;Objective:&lt;/strong&gt; To assess the effects of converting undisturbed natural forest to plantation forest (cypress), grazed pastures and potato fields on soil phosphorus (P) fractions and abundance and diversity of arbuscular mycorrhizal fungi (AMF) in Nyandarua County, Kenya. &lt;strong&gt;Methodology:&lt;/strong&gt; Transects laid out in triplicate were established in each land use type. In potato fields and grazed pastures, transects measured 50 m with three sampling points established 15 m apart along each transect, each point measuring 1 m² divided into 25 grids with each grid being 400 cm². Transect length was increased to 150 m in forest sites due to relatively larger size of the area studied and sampling points were placed at 50 m apart, each point measuring 25 m² and divided into 1² m grids. Soil and plant samples were randomly collected from sampling points and were used to determine chemical properties, soil P fractions and AMF spore examination. Data were analyzed by analysis of variance (ANOVA). &lt;strong&gt;Results:&lt;/strong&gt; Soil chemical properties were significantly (&lt;em&gt;p&lt;/em&gt;&amp;lt;0.001) higher in natural forest compared to potato fields, grazed pasture and cypress forest. On the contrary, readily labile and moderately labile P was higher in fields cultivated with potato (125.3 mg and 258.2 mg P kg&lt;sup&gt;-1&lt;/sup&gt;, respectively) than in natural forest (51.1 mg and 95.3 mg P kg&lt;sup&gt;-1&lt;/sup&gt;) and cypress forest (36.4 mg and 82.7 mg P kg&lt;sup&gt;-1&lt;/sup&gt;, respectively). However, non-labile P was higher in natural forest (599.1 mg P kg&lt;sup&gt;-1&lt;/sup&gt;) and lower in cypress forest (251.3 mg kg&lt;sup&gt;-1&lt;/sup&gt;). Of the ten AMF genera identified, only &lt;em&gt;Glomus&lt;/em&gt; and &lt;em&gt;Acaulospora&lt;/em&gt; were significantly (&lt;em&gt;p&lt;/em&gt;&amp;lt;0.01) affected by land use change, where they were more abundant in fields cultivated with potato than the other three land use types. Land use type did not significantly influence diversity and richness in AMF. However, AMF composition varied across the land use types. &lt;strong&gt;Implication:&lt;/strong&gt; Land use change may negatively affect soil chemical properties, enhance redistribution of soil P, and change AMF community composition, and this could have long-term implications on soil fertility. &lt;strong&gt;Conclusion:&lt;/strong&gt; Land use change from natural ecosystems to croplands, grazed pastures and tree plantations alter soil chemical properties, AMF composition and spore abundance, and redistribute soil P fractions by increasing labile P and reducing non-labile P fractions showing that the type of land use chosen significantly influence soil physical and chemical properties and soil biodiversity.&lt;/p&gt;

Ecotype and fungal endophyte status differentially affect soil arbuscular mycorrhizal community of the native grass Bromus auleticus

In wild native grasses, the colonization of arbuscular mycorrhizal fungi (AMF) is higher in Epichloë-infected plants (E+) compared to Epichloë-free plants (E−). To explore the correlation between the host ecotype, Epichloë association, and the soil AMF community, a common garden experiment was conducted. To achieve this, the soil AMF community of two Bromus auleticus ecotypes, El Palmar (EP) and La Pampa (LP), with either E+ or E−endophyte status, was analyzed using high throughput sequencing. The total mycorrhizal colonization of E+ plants from both EP and LP ecotypes showed significantly higher values (178.68% and 132.34% respectively) compared to E−plants, regardless of the ecotype. Alpha and Beta diversity analysis revealed significant differences in AMF richness and composition between the El Palmar (EP) and La Pampa (LP) ecotypes. However, no differences were observed in the soil AMF communities between E+ and E−plants. In conclusion, this study demonstrates that Epichloë symbiosis and host ecotype have distinct effects on various aspects of the AMF-Bromus auleticus association.

Arbuscular Mycorrhizal Fungi and Diazotrophic Diversity and Community Composition Responses to Soybean Genotypes from Different Maturity Groups

Soybeans can simultaneously form tripartite symbiotic associations with arbuscular mycorrhizal fungi (AMF) and diazotrophs. However, no studies have explored whether soybean genotypes differing in their maturity groups (MGs) may have implications for the recruitment of rhizosphere soil AMF and diazotrophs. We investigated the diversity and community compositions of AMF and diazotrophs in three soybean genotypes differing in their maturity groups (MG) using high-throughput sequencing. The soybean MGs were MG1.4, MG2.2, and MG3.8, representing early, standard, and late maturity, respectively, for the study region. Soil chemical properties and yield-related traits were determined, and co-occurrence network patterns and drivers were also analyzed. The results obtained demonstrated that AMF richness and diversity were relatively stable in the three soybean genotypes, but noticeable differences were observed in diazotrophs, with late maturity being significantly higher than early maturity. However, there were differences in AMF and diazotrophic composition among different MG genotypes, and the changes in the proportion of dominant species in the community were necessarily related to MG genotypes. Co-occurrence network analysis showed that the positive correlation between AMF and diazotrophs gradually decreased in earlier MG genotypes than in the other later MG genotypes. The results of the structural equation model analysis showed that soil organic carbon, AMF, diversity of soil nutrients, and extracellular enzyme activities were important factors driving soybean yield change, with organic carbon accounting for more than 80% of the pathways analyzed. These results suggest that soybean genotype selection based on MG plays an important role in recruiting both AMF and diazotrophic communities, and in comparison to AMF, diazotrophs are more responsive to the different MG genotypes.

Ecological drivers of fine-scale distribution of arbuscular mycorrhizal fungi in a semiarid Mediterranean scrubland.

Arbuscular mycorrhizal (AM) fungi enhance the uptake of water and minerals by the plant hosts, alleviating plant stress. Therefore, AM fungal-plant interactions are particularly important in drylands and other stressful ecosystems. We aimed to determine the combined and independent effects of above- and below-ground plant community attributes (i.e. diversity and composition), soil heterogeneity and spatial covariates on the spatial structure of the AM fungal communities in a semiarid Mediterranean scrubland. Furthermore, we evaluated how the phylogenetic relatedness of both plants and AM fungi shapes these symbiotic relationships. We characterized the composition and diversity of AM fungal and plant communities in a dry Mediterranean scrubland taxonomically and phylogenetically, using DNA metabarcoding and a spatially explicit sampling design at the plant neighbourhood scale. The above- and below-ground plant community attributes, soil physicochemical properties and spatial variables explained unique fractions of AM fungal diversity and composition. Mainly, variations in plant composition affected the AM fungal composition and diversity. Our results also showed that particular AM fungal taxa tended to be associated with closely related plant species, suggesting the existence of a phylogenetic signal. Although soil texture, fertility and pH affected AM fungal community assembly, spatial factors had a greater influence on AM fungal community composition and diversity than soil physicochemical properties. Our results highlight that the more easily accessible above-ground vegetation is a reliable indicator of the linkages between plant roots and AM fungi. We also emphasize the importance of soil physicochemical properties in addition to below-ground plant information, while accounting for the phylogenetic relationships of both plants and fungi, because these factors improve our ability to predict the relationships between AM fungal and plant communities.

Identification of root-associated arbuscular mycorrhizal fungi in cassava (Manihot esculenta Crantz) in Manokwari Regency, West Papua, Indonesia

Arbuscular mycorrhizal fungi (AMF) are crucial for plants growing on marginal soils, especially those with a very high dependence on AMF; one of them is plants with few roots, such as cassava. This study aimed to identify the AMF associated with cassava in six locations in Manokwari Regency, West Papua, Indonesia. The research was carried out using an observation method and purposive sampling at 6 locations. Soil samples were taken from the rhizosphere of 8-month-old cassava plants, with 2 kg of soil at each site. Furthermore, using the host plant Sorghum bicolor L, AMF was trapped in rhizosphere soil samples for three months. The spore morphology identification showed that cassava in North Manokwari District was associated with 3 genera 7 species, West Manokwari District-Manggoapi obtained 3 genera 7 species, Warmare District obtained 2 genera 7 species, Prafi SP-3 District obtained 3 genera 6 species, Masni SP-5 District obtained 3 genera 7 species, and Masni SP-8 District obtained 2 genera 7 species. The highest AMF colonization rate (94%) was found in the roots of the host plant Sorghum bicolor (L.) originating from Masni SP-5 District with the AMF composition consisting of Acaulospora cf. rehmi, Acaulospora cf. spinosa, Acaulospora cf. gerdemanii, Glomus cf. clarum, Gigaspora cf. margarita, Gigaspora cf. rosea, and Gigaspora cf. gigantea.

Effects of microplastics on cadmium accumulation by rice and arbuscular mycorrhizal fungal communities in cadmium-contaminated soil.

Both microplastics (MPs) and cadmium (Cd) are common contaminants in soil-rice systems, but their combined effects remain unknown. Thereby, we explored the effects of three MPs, i.e., polyethylene terephthalate (PET), polylactic acid (PLA), and polyester (PES), on Cd accumulation in rice and the community diversity and structure of arbuscular mycorrhizal fungi (AMF) in soil spiked with or without Cd. Results showed that 2% PLA decreased shoot biomass (-28%), but PET had a weaker inhibitive effect. Overall, Cd alone did not significantly change shoot and root biomass and increased root biomass in combination with 0.2% PES. MPs generally increased soil Cd availability but decreased Cd accumulation in rice tissues. Both MPs and Cd improved the bioavailability and uptake of Fe and Mn in rice roots. MPs altered the diversity and community composition of AMF, depending on their type and dose and co-existing Cd. Overall, 2% PLA caused the most distinct changes in soil properties, plant growth and Cd accumulation, and AMF communities, but showed no synergistic interactions with Cd. In conclusion, MPs can mediate rice performance and Cd accumulation via altering soil properties, nutrient uptake, and root mycorrhizal communities, and biodegradable PLA MPs thought environment-friendly can exhibit higher phytotoxicity than conventional MPs.

Vascular plant and cryptogam abundance as well as soil chemical properties shape microbial communities in the successional gradient of glacier foreland soils

In the glacier forelands, microbes play a fundamental role in soil development and shaping the vegetation structure. Such ecosystems represent various stages of soil development and are, therefore, an excellent place to study the interrelationship between soil, plants, and microorganisms. The aim of the study was to assess the effects of vegetation and soil physicochemical properties developing after glacier retreat on soil microbial communities. Specifically, abundance, species richness and the composition of arbuscular mycorrhizal fungi (AMF), as well as microbial biomass and community structure in soils were compared between plots established in 800-meter transects of three glacier forelands in northern Sweden. The cover of vascular plants and cryptogams, soil C content, AMF spore density and species richness, AMF biomass indicators, total microbial biomass, and bacterial phospholipid fatty acids (PLFA) were significantly and positively related to the distance from the glacier terminus. On the other hand, macronutrient concentrations and pH decreased along with increasing distance. No significant impact of the distance from the glacier terminus on the ratio fungal/bacterial PLFA was observed. Moreover, we found a significant effect of both glacier and the distance from the glacier terminus on the microbial community structure. AMF species richness and spore density in the glacier forelands were generally low, which is probably due to a limited supply of inoculum in primary successional ecosystems. Most microbial biochemical markers and AMF parameters were positively associated with the number of arbuscular mycorrhizal plant species and vascular plant and lichen cover as well as C content in soil, whereas negatively with soil macronutrients and pH. This could be related to an increase in plant cover and a decrease in soil nutrient levels as plant succession progresses. Our results showed that vegetation, soil C content, and microbial communities are interlinked and exhibit concordant patterns along successional gradients.