Soil Arbuscular Mycorrhizal Fungi Research Articles

Mycorrhizal Fungal Inoculum Potential in Crop Rotation Soil With Different Levels of Irrigation

Research indicates arbuscular mycorrhizal fungi (AMF) inoculum potential and AMF biomass production in agricultural soil are strongly influenced by both soil moisture availability and crop rotation (CR) strategies. We hypothesized that AMF biomass production in and inoculum potential of Wyoming semiarid agricultural soil would increase when managed using CR and irrigation. To test this hypothesis, we examined AMF activity (AMF biomarker fatty acid, and AMF infection of roots) in two differently managed soils (no-CR soil and two-year CR soil) in a field experiment. Furthermore, in a greenhouse experiment, we examined AMF activity in the same two CR treatment soils under different irrigation regimes (wet, irrigated to 60% field capacity, and dry, irrigated to 15% field capacity). Notably, the two-year CR soil had greater amounts of AMF biomarker fatty acid and greater inoculum potential, and higher percentage of AMF root colonization compared to no-CR soil. Despite the fact that the CR soil had more AMF propagules, it was less than the undisturbed non-agricultural native sage-grassland soils previously reported. Overall, the findings suggest that high levels of irrigation can inhibit the activity of AMF adapted to semiarid soil conditions and CR can increase activity of AMF in soils from semiarid regions.

Winter forage crops influence soil properties through establishing different arbuscular mycorrhizal fungi communities in paddy field

Winter planting is promising for improving the utilization rate of fallow paddy fields in southern China by establishing arbuscular mycorrhizal fungi (AMF) communities. However, the effects of different winter forage crops on AMF community construction remain unknown. The AMF community establishment of different winter planting forage crops were conducted in oat, rye, Chinese milk vetch, and ryegrass, with winter fallow as a control. The AMF colonization rate, soil AMF spore density, community structure and diversity, and soil physicochemical properties were determined. The results showed that the total nitrogen and available nitrogen in winter Chinese milk vetch were 11.11% and 16.92% higher than those in winter fallow (P < 0.05). After planting winter forage crops, the AMF spore density in winter oat, rye, Chinese milk vetch, and ryegrass soil were 127.90%, 64.37%, 59.91%, and 73.62% higher than that before planting, respectively (P < 0.05). Claroideoglomus was the dominant AMF genus in the soil of winter planting oat, rye, and ryegrass. The average membership function value of winter Chinese milk vetch was the highest, indicating that it had the best comprehensive effect on soil physicochemical properties, AMF community structure and diversity, and fresh forage yield. Winter forage crops could increase the spore pool of soil AMF and improve the soil AMF community structure and diversity. Winter Chinese milk vetch in paddy field had the best comprehensive effect on soil physicochemical properties and soil AMF community according to the comprehensive evaluation. These findings provide a theoretical basis for sustainable development and utilization of the southern rice paddy ecosystem.

Changing plant phosphorus acquisition strategies in relation to altered soil phosphorus fractions after wetland drainage

Abstract Plant phosphorus (P) acquisition strategy is considered to be an intrinsic driver behind plant succession. However, variations in plant P acquisition strategies in connection to soil P fraction changes after wetland drainage remain unclear. To address this issue, here we conducted a study in six distinct wetlands that experienced long‐term (&gt;20 years) artificial drainage, with the adjacent waterlogged wetlands as a control. We analysed plant community composition, biomass and soil P fractions, and identified three plant P acquisition strategies based on soil acid phosphatase activity, plant P resorption efficiency, and soil arbuscular mycorrhizal fungi (AMF) content. We found that soil calcium‐bound P (PCa) and enzyme‐extractable P (Penzyme) were key factors influencing plant P acquisition. Soil PCa correlated negatively with acid phosphatase activity but positively with AMF content. Soil Penzyme negatively impacted P resorption efficiency. The wetlands were categorised into three types based on the change in plant richness and composition, with each exhibiting distinct plant P acquisition strategies. These changes in strategies after drainage corresponded with shifts in soil P fractions. Overall, our study highlights the role of soil P fractions in explaining plant P acquisition strategies after wetland drainage, suggesting P regulations on plant succession and ecosystem services. Read the free Plain Language Summary for this article on the Journal blog.

Native arbuscular mycorrhizal fungi drive ecophysiology through phenotypic integration and functional plasticity under the Sonoran desert conditions.

Knowledge is scarce to what extent environmental drivers and native symbiotic fungi in soil induce abrupt (short-term), systemic (multiple traits), or specific (a subset of traits) shifts in C3 plants' ecophysiological/mycorrhizal responses. We cultivated an emblematic native C3 species (Capsicum annuum var. glabriusculum, "Chiltepín") to look at how the extreme heat of the Sonoran desert, sunlight regimes (low = 2, intermediate = 15, high = 46 mol m2 d-1) and density of native arbuscular mycorrhizal fungi in soil (low AMF = 1% v/v, high AMF = 100% v/v), drive shifts on mycorrhizal responses through multiple functional traits (106 traits). The warming thresholds were relentlessly harsh even under intensive shade (e.g. superheat maximum thresholds reached ranged between 47-63°C), and several pivotal traits were synergistically driven by AMF (e.g. photosynthetic capacity, biomass gain/allometry, and mycorrhizal colonization traits); whereas concurrently, sunlight regimes promoted most (76%) alterations in functional acclimation traits in the short-term and opposite directions (e.g. survival, phenology, photosynthetic, carbon/nitrogen economy). Multidimensional reduction analysis suggests that the AMF promotes a synergistic impact on plants' phenotypic integration and functional plasticity in response to sunlight regimes; however, complex relationships among traits suggest that phenotypic variation determines the robustness degree of ecophysiological/mycorrhizal phenotypes between/within environments. Photosynthetic canopy surface expansion, Rubisco activity, photosynthetic nitrogen allocation, carbon gain, and differential colonization traits could be central to plants' overall ecophysiological/mycorrhizal fitness strengthening. In conclusion, we found evidence that a strong combined effect among environmental factors in which AMF are key effectors could drive important trade-offs on plants' ecophysiological/mycorrhizal fitness in the short term.

Enhanced Soil Fertility and Carbon Dynamics in Organic Farming Systems: The Role of Arbuscular Mycorrhizal Fungal Abundance.

Arbuscular mycorrhizal fungi (AMF) are critical for soil ecosystem services as they enhance plant growth and soil quality via nutrient cycling and carbon storage. Considering the growing emphasis on sustainable agricultural practices, this study investigated the effects of conventional and organic farming practices on AMF diversity, abundance, and ecological functions in maize, pepper, and potato-cultivated soils. Using next-generation sequencing and quantitative PCR, we assessed AMF diversity and abundance in addition to soil health indicators such as phosphorus content, total nitrogen, and soil organic carbon. Our findings revealed that, while no significant differences in soil physicochemical parameters or AMF diversity were observed across farming systems when all crop data were combined, organic farming significantly enhances AMF abundance and fosters beneficial microbial ecosystems. These ecosystems play vital roles in nutrient cycling and carbon storage, underscoring the importance of organic practices in promoting robust AMF communities that support ecosystem services. This study not only deepens our understanding of AMF's ecological roles but also highlights the potential of organic farming to leverage these benefits for improving sustainability in agricultural practices.

Exotic plants introduction changed soil nutrient cycle and symbiotic relationship with arbuscular mycorrhizal fungi in wetland ecological projects.

In the process of applying exotic plants to wetland ecological restoration, insufficiently evaluated alien species may exhibit strong competitiveness and fecundity. Once introduced, they can displace native flora, disrupt the original ecological balance, diminish biodiversity, and even induce ecosystem dysfunction. Furthermore, exotic plants have the potential to alter soil microbial community structure, including the composition and activity of beneficial symbiotic microorganisms such as arbuscular mycorrhizal fungi (AMF), thereby impacting soil nutrient cycling and interplant nutrient competition. Here, we conducted three consecutive years of sampling experiments to investigate the succession of AMF communities associated with the invasive plant Spartina alterniflora along an initial introduction chronosequence, and to identify the key environmental factors influencing its response to S. alterniflora invasion. Our findings reveal that early-stage invasion by S. alterniflora alters the composition of soil AMF communities with unclassified_c__Glomeromycetes and Glomus-viscosum-VTX00063 consistently dominating. Additionally, as the duration of introduction increases, the diversity of rhizosphere soil AMF significantly decreases, while its evenness remains relatively stable. It's indicated that soil ω, AN, AK and N/P ratio were the main influencing factors of the integral AMF community. Notably, soil available phosphorus (AP) emerges as a positive influence on the important AMF taxa. The results confirm the mutual feedback effect between the invasion of the perennial herb S. alterniflora and AMF, in which specific AMF assist in nutrient absorption to promote S. alterniflora growth, potentially facilitating its rapid and successful invasion of new habitats. Given the likely differential effects of AMF communities on various plant species, our findings could contribute to anticipating future AMF-mediated effects during the introduction of alien plants.

Diversified Cover Crops and No-Till Enhanced Soil Total Nitrogen and Arbuscular Mycorrhizal Fungi Diversity: A Case Study from the Karst Area of Southwest China

The deteriorating soil health under continuous monoculture is commonly found across various cropping systems. This study evaluated the effects of different tillage practices (conventional tillage and no till) and species mixtures (legumes and grasses) on arbuscular mycorrhizal fungi (AMF) community properties, soil nutrients, and enzyme activity in a 3-year experiment. Compared with traditional tillage, the number of AMF species under no-till conditions was increased, with the Glomus group being dominant. Under different tillage conditions, TN (total N) and AN (available N) contents under no till were significantly higher than those under conventional tillage, while no significant differences among other nutrients were found. The activities of soil acid phosphatase (S-ACP), soil dehydrogenase (S-DHA), and soil sucrose (S-SC) under conventional tillage were significantly higher than those under no till, and the cover crop mixtures also had an exclusive advantage in yield. Soil organic matter (SOM) indicated a significant negative correlation with glomalin-related soil protein (GRSP). The increase in diversity associated with the AMF species community was strongly correlated with the increase in three enzyme activities, and AN was negatively correlated with all species. Tillage did not significantly change soil chemistry, except for AN, and the high concentration of AN led to a decrease in AMF species. The results of this study showed that no till was an effective measure for enriching soil micro-organism population. Additionally, soil AMF diversity was improved by cover crop mixtures, and microbial diversity was higher than that under monoculture cover crops. Different AMF groups responded differently to tillage and cover crop mixtures. Across all mixtures, the combination of hairy vetch (Vicia villosa R.) and ryegrass (Lolium perenne L.) performed the best.

The communities of arbuscular mycorrhizal fungi established by different winter green manures in paddy fields promote post-cropping rice production1

Winter planting green manures in southern China effectively improve soil properties and rice production through microbial community construction. However, the effects of soil communities of arbuscular mycorrhizal fungi (AMF) from different winter planting green manures on the soil properties and post-cropping rice production remain unclear. In this study, the soil AMF communities of three common winter planting patterns in Southern China, winter fallow, winter ryegrass (Lolium multiflorum L.), and winter Chinese milk vetch (Astragalus sinicus L.), were explored and their effects on post-cropping rice production were investigated. Compared with winter fallow, the winter ryegrass and winter Chinese milk vetch patterns could alleviate soil acidification, significantly increase soil AMF spore density, and improve the soil AMF community structure. Based on sterilized soil, rice production indicators such as thousand-seed weight, theoretical yield, and the grain amylose and total sugar contents of rice inoculated with AMF spores from winter Chinese milk vetch soil were 6.68-53.57% higher than those without AMF inoculation. Rice panicle weight, seed setting rate, and theoretical yield were 15.38-22.71% higher in the treatment with AMF spores from winter ryegrass soil than in the treatments with no AMF inoculation. In addition, the protein, amylose, and total sugar contents of rice grains were 14.92, 104.82, and 802.23 mg kg-1, respectively, which were 31.31, 14.25 and 34.47% higher than those without AMF inoculation. The AMF community dominated by Glomus and Acaulospora in winter Chinese milk vetch had a more positive effect on the improvement of rice yield, while the AMF community dominated by Glomus in winter ryegrass soil was more conducive to rice quality improvement. These findings have revealed the critical role of AMF communities from green manure in rice production, which lays the theoretical basis for a promising strategy to promote the sustainable development of southern winter agriculture.

Impact of wildfire on soil characteristics and arbuscular mycorrhizal fungi.

This study explored whether wildfire alters the soil properties and arbuscular mycorrhizal fungi (AMF) community composition when compared with burnt rangeland, non-burnt rangeland and adjacent tilled in mesothermal ecosystems. The study was carried out in August 2020, 1year later after wildfire. The results of this study showed that the wildfire played a key role in altering soil characteristics and AMF community composition in Bartin Province located in the Western Black Sea Region. Soil samples were made according to standard methods. AMF spores were isolated according to the wet sieving method, and the spores of AMF were identified according to their morphological characteristics. Analysis of variance was performed to determine the differences between the parameters, and correlation analysis was performed to determine the relationships between the parameters. The highest values of soil organic carbon (2.20%), total nitrogen (0.18%), K2O (74.68kg/da), root colonization (87.5%) and the frequency of occurrence of Funneliformis geosporum (20%), Claroideoglomus claroideum (16%) and Claroideoglomus etunicatum (11%) were found in burnt rangeland. Sporulation of Acaulospora dilatata, Acaulospora morrowiae, Acaulospora tuberculata, Scutellospora castanea, Scutellospora coralloidea, Scutellospora scutata, Glomus coremioides and Glomus multicaule was either decreased or completely inhibited in the burnt rangeland. While species diversity of AMF (12) decreased, the number of AMF spores (325.6 (number/50 gr soil)) increased in burnt areas. In conclusion, the number of spores and root colonization of AMF increased but species diversity of AMF reduced after the wildfire. In ecosystems with high fire risk where AMF transfer is planned, it is suggested that it would be more appropriate to select species with an increase in spore number after fire.

Effect of plant communities on bacterial and fungal communities in a Central European grassland

BackgroundGrasslands provide fundamental ecosystem services that are supported by their plant diversity. However, the importance of plant taxonomic diversity for the diversity of other taxa in grasslands remains poorly understood. Here, we studied the associations between plant communities, soil chemistry and soil microbiome in a wooded meadow of Čertoryje (White Carpathians, Czech Republic), a European hotspot of plant species diversity.ResultsHigh plant diversity was associated with treeless grassland areas with high primary productivity and high contents of soil nitrogen and organic carbon. In contrast, low plant diversity occurred in grasslands near solitary trees and forest edges. Fungal communities differed between low-diversity and high-diversity grasslands more strongly than bacterial communities, while the difference in arbuscular mycorrhizal fungi (AMF) depended on their location in soil versus plant roots. Compared to grasslands with low plant diversity, high-diversity plant communities had a higher diversity of fungi including soil AMF, a different fungal and soil AMF community composition and higher bacterial and soil AMF biomass. Root AMF composition differed only slightly between grasslands with low and high plant diversity. Trees dominated the belowground plant community in low-diversity grasslands, which influenced microbial diversity and composition.ConclusionsThe determinants of microbiome abundance and composition in grasslands are complex. Soil chemistry mainly influenced bacterial communities, while plant community type mainly affected fungal (including AMF) communities. Further studies on the functional roles of microbial communities are needed to understand plant-soil-microbe interactions and their involvement in grassland ecosystem services.

Soil organic matter and water content affect the community characteristics of arbuscular mycorrhizal fungi in Helan mountain, an arid desert grassland area in China.

Arbuscular mycorrhizal fungi (AMF) are vital in terrestrial ecosystems. However, the community structure characteristics and influencing factors of AMF in the forest ecosystems of arid desert grassland areas require further investigation. Therefore, we employed high-throughput sequencing technology to analyze the soil AMF community characteristics at different elevations in the Helan mountains. The results revealed that significant differences (P < 0.05) were observed in the soil physicochemical properties among different elevations, and these properties exhibited distinct trends with increasing elevation. Through high-throughput sequencing, we identified 986 operational taxonomic units (OTUs) belonging to 1 phylum, 4 classes, 6 orders, 12 families, 14 genera, and 114 species. The dominant genus was Glomus. Furthermore, significant differences (P < 0.05) were observed in the α-diversity of the soil AMF community across different elevations. Person correlation analysis, redundancy analysis (RDA), and Monte Carlo tests demonstrated significant correlations between the diversity and abundance of AMF communities with soil organic matter (OM) (P < 0.01) and soil water content (WC) (P < 0.05). This study provides insights into the structural characteristics of soil AMF communities at various altitudes on the eastern slope of Helan mountain and their relationships with soil physicochemical properties. The findings contribute to our understanding of the distribution pattern of soil AMF and its associations with environmental factors in the Helan mountains, as well as the stability of forest ecosystems in arid desert grassland areas.

Seven-year long-term inoculation with Funneliformis mosseae increases maize yield and soil carbon storage evidenced by in situ 13C-labeling in a dryland

Arbuscular mycorrhizal fungi (AMF) establish symbiotic relationships with roots of most plants, contributing to plant water uptake and soil carbon (C) sequestration. However, the interactive contribution and of long-term field AMF inoculation and water conservation on maize yield and soil organic carbon (SOC) sequestration in drylands remain largely unknown. After 7-year long-term field inoculation with AMF Funneliformis mosseae, AMF suppression by fungicide benomyl, and no-AMF/no-benomyl control, and two water conservation practices of half-film and full-film mulching (∼50 % and ∼100 crop planted area covered with plastic film), this study thus applied in situ 13CO2-C labeling and high-throughput sequencing to quantify newly photosynthetically assimilated C into different soil C pools including soil aggregates and respiration, and their effects on maize growth and productivity. Results showed that 7-year long-term AMF inoculation significantly increased the relative abundance of F. mosseae in rhizosphere soil and root AMF colonization, indicating that F. mosseae successfully dominated in AMF communities. Compared to no-AMF/no-benomyl control, AMF colonization significantly increased shoot biomass and maize yield by 17.9 % and 20.3 % while mitigated the less water conservation effects of half-film mulching on maize performance. The SOC content under field AMF inoculation SOC was increased from 7.9 to 8.4 g kg−1 and also the mean weight diameter of aggregates (1.21 to 1.35), e.g. aggregate stability. After 1 and/or 40 days 13C labeling, the enhanced 13C translocations into macro-aggregates with decreased 13C emissions from microbial decomposition under field AMF inoculation had contributed to SOC conservation in bulk soil. These results suggest that AMF inoculation in dryland crops is promising to increase crop yield while promoting more atmospheric CO2 fixation in soil aggregates. A long-term field AMF inoculation will enhance our understanding of applying beneficial mycorrhizal fungi to enhance soil C sequestration and also crop yield via plant-fixed atmospheric CO2 in semi-arid and arid farmlands.

Untangling the effect that replacing Ethiopia's natural forests with exotic tree plantations has on arbuscular mycorrhizal fungi

Arbuscular mycorrhizal fungi (AMF) have a broad distribution and establish symbiotic relationships with vascular plants in tropical regions. They play a crucial role in enhancing plant nutrient absorption, mitigating pathogenic infections, and boosting the resilience of host plants to abiotic stresses, including drought under specific conditions. Many natural forests in Ethiopia are being replaced by monospecific plantations. However, the impact of these actions on AMF is unknown and, despite their ecological functions, AMF communities in various forest systems have not been thoroughly investigated. In this study, we assessed soil AMF communities in natural and plantation forests by DNA metabarcoding of the ITS2 rDNA region and assessed the influence of climate and environmental variables on the AMF community. In total, 193 AMF operational taxonomic units (OTUs), comprising nine families and 15 genera, were recorded. Glomerales was the dominant order (67.9 % of AMF OTUs) and Septoglomus fuscum, Diversispora insculpta, and Funneliformis mosseae were the dominant species. AMF were more abundant in natural forests than in plantation forests and the composition of AMF communities differed significantly from those of plantation forest. In plantation forests, soil pH, organic carbon, total nitrogen, and available phosphorus significantly influenced the composition of AMF communities, whereas in natural forest, electrical conductivity, annual rainfall, and cumulative rainfall before sample collection were significantly correlated with AMF. SIMPER analysis identified the AMF responsible for composition variances among different forest types, with the Glomeraceae family being the most significant contributor, accounting for nearly 60 % of the dissimilarity. Our findings further our understanding of the ecological niche function and the role of AMF in Ethiopia's natural forest systems and highlight the importance of prioritizing the sustainable development of degraded natural forests rather than plantations to ensure the preservation of habitats conducive to maintaining various AMF communities when devising conservation and management strategies.

Soil compaction reversed the effect of arbuscular mycorrhizal fungi on soil hydraulic properties

Arbuscular mycorrhizal fungi (AMF) typically provide a wide range of nutritional benefits to their host plants, and their role in plant water uptake, although still controversial, is often cited as one of the hallmarks of this symbiosis. Less attention has been dedicated to other effects relating to water dynamics that the presence of AMF in soils may have. Evidence that AMF can affect soil hydraulic properties is only beginning to emerge. In one of our recent experiments with dwarf tomato plants, we serendipitously found that the arbuscular mycorrhizal fungus (Rhizophagus irregularis ‘PH5’) can slightly but significantly reduce water holding capacity (WHC) of the substrate (a sand–zeolite–soil mixture). This was further investigated in a subsequent experiment, but there we found exactly the opposite effect as mycorrhizal substrate retained more water than did the non-mycorrhizal substrate. Because the same substrate was used and other conditions were mostly comparable in the two experiments, we explain the contrasting results by different substrate compaction, most likely caused by different pot shapes. It seems that in compacted substrates, AMF may have no effect upon or even decrease the substrates’ WHC. On the other hand, the AMF hyphae interweaving the pores of less compacted substrates may increase the capillary movement of water throughout such substrates and cause slightly more water to remain in the pores after the free water has drained. We believe that this phenomenon is worthy of mycorrhizologists’ attention and merits further investigation as to the role of AMF in soil hydraulic properties.

Moisture content and mycorrhizal fungi in maternal environment influence performance and composition of Lallemantia species offspring

The availability of soil water content and nutrition in the maternal plant environment plays pivotal roles in shaping the performance, physio-biochemical properties, and chemical composition of the produced seed. This study aimed to investigate the effects of water and arbuscular mycorrhizal fungi (AMF) of maternal plant environment on performance, physio-biochemical properties, and chemical compositions of Lallemantia species offspring. A split-factorial experiment was performed using a randomized complete block design (RCBD) with three replications. The main plot consisted of three drought stress (30 %, 60 % and 90 % of soil available water depletion). The subplots were the factorial combination of arbuscular mycorrhizal fungi (AMF− and AMF+) and Lallemantia species (L. iberica and L. royleana). The offspring of both Lallemantia species experienced a decrease in seed performance, superoxide dismutase, catalase, ascorbate peroxidase enzyme activities, proline, and chemical composition as well as a rise in hydrogen peroxide and lipid peroxidation due to the limited availability of water in the maternal plant environment. On the other hand, providing adequate nutrition in the maternal plant environment resulted in improved germination index, increased starch, and oil content, as well as higher levels of nitrogen and phosphorus in the offspring of both Lallemantia species. Compared to the offspring of L. royleana, the offspring of L. iberica had a higher number of achenes, seeds, seed weight, larger seed size, greater germination index, and higher levels of starch, oil, nitrogen, phosphorus, potassium, and calcium. In contrast, the offspring of L. royleana exhibited higher longevity, enhanced germination under osmotic and salinity stress, increased proline levels, and higher activities of antioxidant enzymes such as superoxide dismutase, catalase, and ascorbic peroxidase as well as sucrose and total soluble sugar. The study concludes that the best seed performance, antioxidant enzyme activities, and carbohydrate levels were observed in the offspring of both Lallemantia species produced under 60 % soil available water depletion with AMF inoculation in the maternal plant environment. These findings highlight the significant impact of the soil available water depletion and AMF inoculation on the seed performance, physio-biochemical properties, and chemical composition of the offspring, providing valuable insights for optimizing seed production and performance.

Arbuscular mycorrhizal fungi affect the response of soil CO2 emission to summer precipitation pulse following drought in rooted soils

Drought and extreme precipitation are projected to occur more frequently as a consequence of climate change, with uncertain implications for soil CO2 emission. Although studies have revealed the response patterns of soil CO2 emission to precipitation pulse, the effects of forest plant roots on this relationship after drought are still poorly understood. Here, a field experiment was performed to examine the differences in soil CO2 emission and microbial community between rootless and rooted soils, pretreated with three drought intensities (control, moderate, and severe), and rewetted with different water additions (0, 5, 10, and 20 mm) in a temperate forest. Compared with control soils, whether the water was added or not, severe drought suppressed soil CO2 emission for both root-excluded and -included soils. Regardless of drought intensities, significantly positive effects (19.4–44.9%) of precipitation pulse on soil CO2 emission were only detected in the root-included soils. Both the contribution of root-derived CO2 to the stimulated soil CO2 emission and biomass of soil arbuscular mycorrhizal fungi (AMF) substantially increased with elevated precipitation levels. The enhanced soil CO2 emission following precipitation pulse is primarily due to the increase in root-derived CO2 in the rooted soils, likely resulting from the enhanced biomass of soil AMF. This study provides empirical evidence on the primacy of AMF in root-derived CO2 and thus the response of soil CO2 emission to precipitation pulse in forest ecosystems.

Thresholds of Nitrogen and Phosphorus Input Substantially Alter Arbuscular Mycorrhizal Fungal Communities and Wheat Yield in Dryland Farmland.

Arbuscular mycorrhizal (AM) fungi are essential for preserving the multifunctionality of ecosystems. The nitrogen (N)/phosphorus (P) threshold that causes notable variations in the AM fungus community of the soil and plant productivity is still unclear. Herein, a long-term (18 years) field experiment with five N and five P fertilizer levels was conducted to investigate the change patterns of soil AM fungus, multifunctionality, and wheat yield. High-N and -P fertilizer inputs did not considerably increase the wheat yield. In the AM fungal network, a statistically significant positive correlation was observed between ecosystem multifunctionality and the biodiversity of two primary ecological clusters (N: Module #0 and P: Module #3). Furthermore, fertilizer input thresholds for N (92-160 kg ha-1) and P (78-100 kg ha-1) significantly altered the AM fungal community, soil characteristics, and plant productivity. Our study provided a basis for reduced N and P fertilizer application and sustainable agricultural development from the aspect of soil AM fungi.

Common soil history is more important than plant history for arbuscular mycorrhizal community assembly in an experimental grassland diversity gradient

The relationship between biodiversity and ecosystem functioning strengthens with ecosystem age. However, the interplay between the plant diversity - ecosystem functioning relationship and Glomeromycotinian arbuscular mycorrhizal fungi (AMF) community assembly has not yet been scrutinized in this context, despite AMF’s role in plant survival and niche exploration. We study the development of AMF communities by disentangling soil- and plant-driven effects from calendar year effects. Within a long-term grassland biodiversity experiment, the pre-existing plant communities of varying plant diversity were re-established as split plots with combinations of common plant and soil histories: split plots with neither common plant nor soil history, with only soil but no plant history, and with both common plant and soil history. We found that bulk soil AMF communities were primarily shaped by common soil history, and additional common plant history had little effect. Further, the steepness of AMF diversity and plant diversity relationship did not strengthen over time, but AMF community evenness increased with common history. Specialisation of AMF towards plant species was low throughout, giving no indication of AMF communities specialising or diversifying over time. The potential of bulk soil AMF as mediators of variation in plant and microbial biomass over time and hence as drivers of biodiversity and ecosystem relationships was low. Our results suggest that soil processes may be key for the build-up of plant community-specific mycorrhizal communities with likely feedback effects on ecosystem productivity, but the plant-available mycorrhizal pool in bulk soil itself does not explain the strengthening of biodiversity and ecosystem relationships over time.

Characteristics of the Rhizospheric AMF Community and Nutrient Contents of the Dominant Grasses in Four Microhabitats of the Subalpine Zone in Northwestern Yunnan, China

At the southeastern periphery of the Tibetan Plateau, the subalpine ecosystem hosts grasses as some of the most substantial species. However, the community and function of arbuscular mycorrhizal fungi (AMF) around the rhizospheres of grasses in the subalpine zone are still poorly understood. In the present study, 28 soils and 11 species of dominant grasses collected from four microhabitats (shrubland, grassland, woodland, and forest) in the subalpine zone of northwestern Yunnan, China, were used to investigate the AMF community by Illumina MiSeq high-throughput sequencing technology as well as nutrient contents. Among the four microhabitats, the maximum soil nutrient levels around the rhizospheres of grasses were observed in woodland. The nitrogen, phosphorus, and potassium concentrations in Dactylis glomerata shoots were significantly higher than those in the other 10 grass species. The AMF diversity of grassland in summer was substantially greater than that of the other three microhabitats (p &lt; 0.05). Discrepancies were observed within a given plant species across microhabitats; for example, in summer, the nitrogen concentration in the shoot of Iris tectorum in woodland was significantly higher than that in both forest and shrubland (p &lt; 0.05). A total of eight genera were detected in the AMF communities, which were dominated by Glomus, with a relative abundance of 45.4–94.4% in summer and 60.5–84.3% in winter. Moreover, the abundance of Glomus was significantly positively correlated with the content of alkali-hydrolyzable nitrogen in soil and nitrogen in grasses according to the Mantel test. As a critical nutrient element in soil, nitrogen is beneficial for plant growth. Thus, these results provide a better understanding of the resilience of soil AMF community and the ecological adaptability of grasses in the subalpine ecosystems of northwestern Yunnan.

Optimum planting density of Amorpha fruticosa promotes the recovery of understory vegetation and the arbuscular mycorrhizal fungal community in plantations in arid coal mining areas

AbstractEstablishment of plantations may be a useful means of vegetation reconstruction in coal mining areas, especially in fragile environments. However, the influence of shrub planting on the relationship between understory vegetation and soil microorganisms remains poorly understood. Here, we describe a field experiment in which the relationships between understory vegetation and soil microorganisms under different planting densities of Amorpha fruticosa L. (A. fruticosa) were investigated. Compared with areas allowed to recover naturally, shrub planting changed the community and increased the biomass of understory vegetation and soil microbes, especially of arbuscular mycorrhizal fungi (AMF). Planting density was also a key factor that influenced understory vegetation and the soil AMF community and biomass. The maximum diversity of understory vegetation and the AMF community occurred at an intermediate density of introduced shrubs, which was considered to be the optimum density of A. fruticosa. The major soil nutrient cycles that influence understory vegetation and the AMF community were also investigated. An optimum density of introduced shrubs was important in the ecological reconstruction of vegetation in the coal mining area. There may also have been an optimum relationship between the understory vegetation and soil microorganisms especially with AMF in the experimental conditions.