Mycorrhizal fungi are a ubiquitious group of symbiotic fungi in nature that form symbiotic associations with most terrestrial plants, playing a crucial role in plant physiological processes and ecosystem functioning. In these symbiotic relationships, mycorrhizal fungi receive photosynthesis-derived carbon from their host plants and, in turn, facilitate the host plants with regard to nutrient acquisition and stress tolerance. Recently, the rapid development of molecular biology and bioinformatics has significantly advanced our understanding of mycorrhizal physiology and ecology. In this review, we synthesize current knowledge on the differences in the evolutionary history of arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi, as well as their impacts on the physiological and ecological functions of host plants. We further discussed how these differences affect the nutrient cycling of global terrestrial ecosystems and the structure and function of plant communities. We showed that the origin and evolution of AM and ECM fungi is a process of long-term mutual adaptation and selection with terrestrial plants. During the evolution, mycorrhizal fungi have gradually refined their plant-dependent nutrient acquisition mechanisms, while plants have developed diverse growth strategies to optimize symbiosis with mycorrhizal fungi. In these mutually beneficial interactions, mycorrhizal fungi not only enhance the nutrient uptake and utilization in host plants and improve their tolerance to biotic and abiotic stresses, but also participate in global biogeochemical cycles. Thus, mycorrhizal fungi play a vital role in maintaining the balance and stability of biodiversity and terrestrial ecosystems. Finally, we proposed future research directions, including the response of mycorrhizal fungi to global change, their roles in multi-trophic associations and urban ecosystems, as well as their applications in production practices and diversity conservation, aiming to provide novel insights and approaches to address various ecological and social challenges.

Arbuscular mycorrhizal fungi (AMF), widely distributed in terrestrial ecosystems, form symbiotic associations with most terrestrial plants. Their extraradical hyphal networks mediate plant-soil interactions, playing indispensable roles in enhancing ecosystem productivity, sustaining biodiversity, and maintaining soil health. While the roles of AMF in enhancing plant nutrient acquisition and stress tolerance are well documented, comprehensive assessments of their ecosystem-scale functions remain scarce. More importantly, methodologies for the targeted manipulation of AMF communities and their ecological functions are still underdeveloped. This review systematically summarizes the ecological functions of AMF from four aspects: ecosystem productivity, biodiversity-ecosystem stability relationships, biogeochemical cycling, and soil health. To address current technical bottlenecks in AMF community regulation, we propose an ecological regulation framework for the application of AMF in improvement of ecosystem functions, including the activation of indigenous fungal consortia, the application of exogenous inoculants, and optimizing context-specific management practices. This framework refines a robust, AMF-centered soil ecological regulation paradigm to facilitate the development of mycorrhizal technologies. Future studies should prioritize the multidimensional interactions among AMF, host plants, and environmental factors, to address the multiple challenges associated with the targeted regulation of AMF communities. This includes advancing microbial regulation strategies, developing multifunctional consortia, and optimizing long-term field management practices. Ultimately, these efforts aim to promote the effective application of mycorrhizal technologies in ecological restoration and sustainable agriculture.

Mycorrhizal fungi serve as key regulators of underground common networks of plants, playing a critical role in maintaining plant species coexistence and biodiversity through “carbon-nutrient/water” exchange and multi-species interconnections. With advances in mycorrhizal ecology, research on the effects of mycorrhizal fungi on plant-plant interactions and their underlying mechanisms has deepened. To systematically summarize the roles and mechanisms by which mycorrhizal fungi maintain plant species coexistence, this review synthesizes current research on how mycorrhizal fungi influence plant species coexistence and analyzes emerging trends in this field. Mycorrhizal fungi maintain plant species coexistence primarily through the following pathways: (1) driving differentiation in plant strategies for water and nutrient uptake and utilization, thereby enhancing resource-use efficiency; (2) mediating nutrient redistribution via common mycorrhizal networks to alleviate competition among plants; (3) enhancing plant resistance to biotic and abiotic stresses through physical barriers, induced resistance, and defensive signal transfer; and (4) recruiting mycorrhizal helper bacteria (MHB) to form multi-scale mutualistic networks, thereby contributing to the stability of soil ecosystems. At the same time, mycorrhizal fungi are themselves influenced by plant species coexistence. The diversity and coexistence context of host plants can regulate fungal diversity, promote diversification in mycorrhizal resource-acquisition strategies, and further enhance the stability of the plant-fungal symbioses. Future research should focus on in situ experiments and multifactor coupling studies, elucidate molecular signaling and nutrient exchange mechanisms within mycorrhizal symbiosis, quantify the ecological functions of mycorrhizal networks, and validate their modes of action. Additionally, more attention should be directed toward understudied types of mycorrhizal associations.

Forest as the dominant component of terrestrial ecosystems, hinges on internal nutrient cycling mechanisms to support individual plant development and the maintenance of ecosystem functions. Arbuscular mycorrhizae (AM) and ectomycorrhizae (ECM), the two most widespread mycorrhizal types in forest ecosystems, playing pivotal roles in regulating nutrient cycling and sustaining functional stability along the “soil-plant-litter continuum”. Although numerous efforts have explored the effects of mycorrhizal types on key nutrient cycling processes in forests, these studies focus more on isolated process, with limited attention to the holistic nutrient cycling mediated by mycorrhizal associations. This review synthesizes research from the past three decades to systematically examine the roles and underlying mechanisms through which AM and ECM-associated plants influence key processes across the internal nutrient cycling, including nutrient mineralization and mobilization, nutrient uptake by mycorrhizal-root systems, nutrient resorption from senescent organs, and nutrient return through litter decomposition. It further elucidates the self-sustaining nutrient dynamics of forest ecosystems dominated by different mycorrhizal types, aiming to provide insights into how nutrient cycling strategies shaped by mycorrhizal symbioses respond and adapt to forest management and global environmental change. Finally, we propose future research directions: (1) investigating the role of Common Mycorrhizal Networks (CMNs) in internal nutrient cycling under AM- versus ECM-dominated stands, while focusing on less-studied mycorrhizal types (e.g., dual-mycorrhizal plants, legumes with rhizobia-AM/ECM symbiosis) and ericoid mycorrhiza (ERM); (2) developing “mycorrhiza-site” matching models and mycorrhizal trait databases based on AM and ECM strategic differentiation, to optimize tree species selection in reforestation and afforestation across different site conditions; (3) assessing the buffering capacity of shifts in AM and ECM distributions in nutrient cycling under global change and (4) integrating long-term and multidimensional monitoring to unravel the co-evolutionary dynamics among mycorrhizal types, soil environments, and microbial communities driving nutrient cycling.

Phosphorus (P) is an essential macronutrient for plant growth and development, and its bioavailability has a profound impact on the structure and function of ecosystems. Most plants form symbiotic associations with either arbuscular mycorrhizal (AM) fungi or ectomycorrhizal (ECM) fungi, which can significantly enhance their ability to acquire and utilize P. Although numerous studies have explored the differences in P acquisition and utilization strategies between AM and ECM plants, few have systematically synthesized these strategies. In this paper, we comprehensively review the P acquisition and utilization strategies from four perspectives: root morphology and architecture, root physiological traits, root-microbe interactions, and P resorption efficiency. It is concluded here that there exist significant differences in P acquisition and utilization strategies between AM and ECM plants. Specifically, AM plants usually form a mutually beneficial relationship with microorganisms that rapidly mineralize organic matter, have a limited extracellular enzyme secretion capacity, and prefer to absorb inorganic P, therefore adopting an “acquisition strategy”. In contrast, ECM plants have a strong ability to secrete extracellular enzymes and other secretions that enable them to utilize organic P, and therefore adopt a “conservation strategy”. Finally, this review proposes six research directions that need to be addressed to overcome current limitations in the future research. Overall, this review not only deepens our theoretical understanding of mycorrhizal-mediated P cycling processes, species coexistence, and productivity maintenance mechanisms, but also provides theoretical guidance for species selection, species configuration, and nutrient management in agricultural and forestry production and ecological restoration practices.

Alpine ecosystems, characterized by high latitudes, high altitudes, cold climates, and extensive permafrost, are highly sensitive to global climate change. Ectomycorrhizal fungi (ECMF) represent a major group of symbiotic microorganisms associated with dominant plant species in these ecosystems. By forming unique ectomycorrhizal structures with host plants, these fungi establish mutualistic relationships that promote seedling growth, enhance water and nutrient uptake, and improve host resistance to biotic and abiotic stresses. Through dual pathways of “carbon input-stabilization” and “nitrogen mineralization-uptake”, ECMF regulate material cycling and serve as key drivers of carbon and nitrogen dynamics. This review summarizes the critical roles of ECMF in carbon and nitrogen cycling within alpine ecosystems and their responses to climate change. It emphasizes the importance of preserving ECMF diversity and key functional groups to maintain ecosystem stability and nutrient processing under global change scenarios. Such conservation efforts provide essential scientific support for protecting vulnerable alpine habitats and mitigating climate-related threats. Future research should further investigate the response mechanisms and feedback regulations of ECMF functional traits and diversity under multiple-factor climate change. Integrating mycorrhizal ecology into the “One Health” framework will better serve the holistic health of both ecosystem and human societies.

Mycorrhizal fungi are crucial components of plant rhizosphere microbiota and key players in terrestrial biogeochemical cycles. Arbuscular mycorrhizal (AM) fungi can form symbiotic relationships with more than 70% of terrestrial plants and their origin can be traced back to the Devonian period, 460 million years ago. They played an important role in the transition of plants from aquatic to terrestrial environments and continue to profoundly affect the growth performance of plants and their ecosystem functions. In the peri-arbuscular space of AM symbiosis, plants provide carbon fixed by photosynthesis in exchange for mineral nutrients, especially phosphorus and nitrogen. In the hyphosphere, many bacteria are involved in the establishment of AM symbiosis. These bacteria obtain carbon from extraradical hyphal exudates and mineralizing organic compounds to enhance the availability of mineral nutrients for the fungi. Therefore, plants, AM fungi and hyphospheric bacteria form a continuum and are accompanied by top-down carbon flows and bottom-up nutrient flows. In this review, we first introduce the latest research on how plants, AM fungi and the related hyphospheric bacteria exchange carbon from host plants and mineral nutrients from the soil. These exchanges provide energy for microbial partners and deliver nutrients for plants that are necessary for growth and development. Secondly, we analyze in detail the mechanism by which the plant-AM fungi-bacterial continuum maintains cross-kingdom cooperation, which is conducive to a better understanding of the complex ecological relationships between plants, AM fungi and soil bacteria. This provides information on their evolutionary significance and a theoretical basis and technical pathway for sustainable agriculture grounded in plant-microbe interactions.

As typical emerging contaminants with global distribution, microplastics are frequently detected in terrestrial ecosystems, including agricultural soils. Available evidences indicate that microplastics can alter soil physicochemical properties, and affect soil biota, plant performance, and ecosystem functions. As the most ubiquitous plant symbiotic fungi in soils, arbuscular mycorrhizal (AM) fungi can enhance stress resistance of their host plants through multiple mechanisms and play a critical role in maintaining ecosystem stability. This review synthesizes current research advances in the interactions between soil microplastics and AM fungi. Microplastics in soil can directly affect AM fungi through adsorption and immobilization, or by releasing co-contaminants, and indirectly influence fungal colonization and community structure by altering soil properties (e.g., pH, nutrient availability), pollutant speciation and toxicity, microbial community composition and activity, and plant performance. On the other side, AM fungi exhibit strong tolerance to microplastics, and may alleviate negative impacts of microplastic contamination on plant and soil environment through multiple pathways, such as improving soil structure, mitigating plant nutrient limitations caused by microplastics, immobilizing microplastics via fungal structures (e.g., extraradical hyphae) to reduce their uptake and translocation by plants. Overall, the interactions between microplastics and AM fungi vary with microplastic characteristics (e.g., type, dose, size, and shape), plant species, soil properties, and exposure conditions, as a result it is still difficult to reach general conclusions. Finally, based on identifying current knowledge gaps, future research priorities are proposed to establish reliable quantification method for microplastics in the soil-plant systems, to assess the ecotoxicological effects of microplastic metabolites and composite pollution on AM fungi, and to reveal the influences of AM fungi on environmental behavior of soil microplastics and its ecological impacts, which will provide theoretical and technical support for the application of mycorrhizal technology to tackle soil microplastic pollution challenges.

Aims Investigating the variation in arbuscular mycorrhizal fungal (AMF) community structure and its driving factors in the alpine wetlands of the Yellow River Source Region within Sanjiangyuan National Park can provide a scientific basis for ecosystem conservation and sustainable management in this area.

Methods Alpine riverine wetlands and alpine swamp wetlands in the Yellow River Source Region were selected as the study objects. An integrated approach combining field investigation and sampling, laboratory analyses, and high-throughput sequencing was employed to systematically examine AMF community structure across wetland types and dominant plant species, and to identify the key factors driving community variation.

Important findings Vegetation cover was significantly lower in swamp wetlands than in riverine wetlands, whereas soil electrical conductivity, total carbon, and total nitrogen contents were significantly higher. In total, 2 799 amplicon sequence variants (ASVs) belonging to the phylum Glomeromycota were identified and classified into 9 families and 10 genera, with Claroideoglomus and Glomus being the main predominant taxa. AMF α-diversity did not differ significantly between wetland types, whereas β-diversity showed significant differences. Variance partitioning analysis (VPA) indicated that wetland type and abiotic factors jointly explained 4.67% of community variation, with abiotic factors alone accounting for 3.39%, which was higher than the independent effect of wetland type (1.04%). Likewise, plant species and abiotic factors together explained 5.00% of AMF community variation, with the independent contribution of abiotic factors (2.04%) being slightly higher than that of plant species (1.38%). Mantel tests and canonical correspondence analysis (CCA) further demonstrated that plant richness, soil moisture, soil nutrient contents, and elevation were the key drivers of AMF community structure. In summary, AMF community structure in the alpine wetlands of the Yellow River Source Region is primarily driven by abiotic factors, while also being synergistically influenced by biotic components. These findings provide important scientific support for the development of targeted wetland ecological management strategies.

Aims Phosphorus (P) is an essential nutrient for plant growth and a critical factor in determining forest productivity. Most terrestrial plants can form symbiotic associations with arbuscular mycorrhizal (AM) or ectomycorrhizal (ECM) fungi to enhance their phosphorus uptake. AM and ECM mycorrhiza vary significantly in their P-absorption strategies, which impacts the P cycling in ecosystems. Understanding how soil P availability varies across the forests dominated by AM and ECM trees can be conducive to elucidating the mechanisms of productivity maintenance in subtropical forests and guiding forest nutrient management.

Methods We established 35 forest plots across a natural gradient of ECM tree dominance in the Badagongshan Nature Reserve, Hunan Province. We measured the contents of four forms of soil bioavailable P (CaCl₂-P, enzyme-P, citrate-P, HCl-P), and analyzed their relationships with ECM tree dominance. Correlation analyses were further employed to identify the key factors influencing soil bioavailable P contents.

Important findings The results revealed that enzyme-P content increased significantly with ECM tree dominance, while CaCl₂-P, citrate-P and HCl-P contents showed no significant correlations with ECM tree dominance. CaCl₂-P content was positively correlated with leaf litter P content. Citrate-P and HCl-P contents were positively correlated with the contents of soil organic carbon, total nitrogen, and microbial biomass carbon. Enzyme-P content was positively correlated with the contents of soil organic carbon and dissolved organic carbon, and negatively correlated with soil pH. Additionally, soil acid phosphatase activity increased significantly with ECM tree dominance. In conclusion, ECM-dominated forests exhibit higher levels of enzyme-hydrolysable P and acid phosphatase activity, which can facilitate P solubilization through organic P mineralization, thereby promoting the rapid growth of ECM trees in subtropical forests.

Aims This study examines the growth responses of major afforestation tree species in Northeast China, specifically Fraxinus mandshurica (a broadleaf species associated with arbuscular mycorrhizal fungi) and Larix gmelinii (a coniferous species associated with ectomycorrhizal fungi), to varying levels of dry and wet deposition of reduced nitrogen. The study aims to enhance our understanding of the relationship between seedling growth patterns and atmospheric nitrogen deposition forms, thereby providing a theoretical foundation for precise nutrient management in seedling cultivation.

Methods The research utilized arbuscular mycorrhizal (AM) seedlings of F. mandshuricaand ectomycorrhizal (ECM) seedlings of L. gmelinii as test plants, and simulated varying levels of dry and wet reduced nitrogen deposition: 0 (CK), 35 (ND-35), 70 (ND-70), 35 (NW-35), and 70 (NW-70) kg N·hm^-2·a^-1. We assessed changes in seedling growth, photosynthetic capacity, root development, and mycorrhizal infection rates of the two types of seedlings.

Important findings Under conditions of atmospheric dry and wet nitrogen deposition, seedlings of both mycorrhizal types gradually reduced their mycorrhizal dependence. The primary response are the enhancement of their photosynthetic rate and an increase in root absorption capacity. (1) During nitrogen dry deposition, a significant increase in leaf and total biomass was observed for arbuscular mycorrhizal seedling of F. mandshurica, attributed to changes in photosynthetic capacity. Under the ND-70 treatment, the net photosynthetic rate, total chlorophyll content, and leaf biomass increased by 49.61%, 76.29% and 53.84% respectively, compared to the control. In contrast, during nitrogen wet deposition, nitrogen use efficiency increased primarily due to an increased contact area between absorbing roots and soil. Under NW-35 and NW-70 treatments, the surface area of absorbing roots increased by 14.96% and 16.17%, respectively, compared to the control. (2) Ectomycorrhizal seedlings of L. gmelinii exhibited a more pronounced response to nitrogen wet deposition, primarily enhanced the absorption capacity of the root system through the elongation and thinning of the absorbing roots. Under NW-70 treatment, the absorbing root length increased by 20.70% compared to the control, while the average diameter and cortical thickness of the absorbing roots decreased by 10.14% and 27.25%, respectively. The study performed an in-depth analysis of the relationship between mycorrhizal types and atmospheric reduced nitrogen deposition, serving as a reference for the precise nutrient management for tree seedlings with different mycorrhizal types.

Aims Drought is one of the major stresses that forest ecosystems are facing globally, directly affecting plant growth and soil microorganism activities and indirectly altering soil organic carbon dynamics. Temperate forests play an important role in global carbon storage and climate regulation, but the mechanism of soil carbon dynamics in response to drought stress remains less understood, particularly mycorrhiza-mediated soil organic carbon processes.

Methods The study was conducted in a warm temperate oak forest (dominated by Quercus aliena var. acuteserrata) subjected to long-term manipulative drought, using in situ microcosms incubation with different mesh sizes (0.001, 0.053, 1.45 mm). It focused on investigating the distinct effects of fine roots, mycorrhizal fungi, and free-living microorganisms on soil enzyme activities and content of two organic carbon fractions: particulate organic carbon (POC) and mineral-associated organic carbon (MAOC).

Important findings The results showed that plants coped with water stress by increasing belowground carbon allocation. Hydrolytic enzyme activity was enhanced due to the key carbon source support provided by fine roots and mycorrhizal fungal exudates, while oxidative enzyme activity was primarily regulated by water availability and soil pH. Peroxidase activity significantly decreased under drought treatment, which promoted the accumulation of POC in the 0.001 mm and 0.053 mm microcosms by inhibiting the decomposition of complex compounds. Furthermore, carbon input from the biomass of fine roots and mycorrhizal fungi is also an important source of POC. Unlike POC, MAOC accumulation was more strongly driven by microbial metabolism and soil environmental changes rather than by plant biomass inputs. In this study, we elucidated for the first time the functional differentiation of fine roots, mycorrhizal fungi and non-symbiotic microorganisms and their synergistic roles under drought stress in a warm-temperate oak forest. The results showed that drought significantly affects the stability of soil carbon pools by altering the dynamics of enzyme activities and carbon fractions regulated by soil environment and belowground carbon allocation. These findings provided a new theoretical basis for the prediction of forest soil carbon cycle under climate change, as well as scientific support for soil management and carbon pool optimization.

Aims The symbiosis between plants and arbuscular mycorrhizal fungi (AMF) constitutes a critical nutrient transfer network in terrestrial ecosystems, playing an essential role in sustaining ecosystem functions. However, AMF community composition and its ecological mechanism underlying their functional responses to global change remains poorly understood.

Methods By integrating a multi-year precipitation increase field experiment in a semi-arid grassland on the Loess Plateau with MiSeq sequencing, we measured plant biomass, root traits, and AMF community composition, and explored the effect of precipitation increase on plant resource acquisition strategies.

Important findings Our results showed that precipitation increase altered plant community composition, favoring subshrubs and forbs over grasses. Compared to grass, subshrub and forb often have thicker and shorter roots, which may enhance the colonization potential of AMF. MiSeq sequencing revealed that precipitation increase significantly altered the AMF community composition, increasing the relative abundance of Gigasporaceae and Paraglomeraceae, while reducing the relative abundance of Glomeraceae. Furthermore, precipitation increase enhanced the complexity of AMF community network. In conclusion, our findings demonstrate that precipitation increase regulates plant water and nutrient acquisition pathway via altering plant functional group growth, root traits, and AMF community composition. These results indicate that precipitation increase may have profound effects on nutrient cycling in grassland ecosystems via regulating the plant and AMF interaction network.

Aims The symbiotic relationship between arbuscular mycorrhizal fungi (AMF) and plant roots enhances nutrient acquisition in plant communities and plays a vital role in sustaining key functions and ecological processes in grassland ecosystems. However, the response patterns of AMF communities to varying grazing intensities remain under debate, and the mechanisms by which these communities influence soil multifunctionality (SMF) under grazing disturbance are not yet fully understood.

Methods To address these knowledge gaps, this study investigated mountain meadow steppes on the northern slope of the Tianshan Mountains in Xinjiang under three grazing intensities: ungrazed, lightly grazed, and heavily grazed. High-throughput sequencing was used to characterize the composition of AMF communities and to construct their co-occurrence networks. A weighted average method, based on cluster analysis, was applied to comprehensively evaluate SMF and to analyze how AMF community characteristics vary with grazing intensities and how these variations influence SMF.

Important findings The results indicated that the dominant AMF genera in the three grazing treatments were Glomus and Diversispora. As grazing intensity increased, AMF community diversity, as along with network stability, complexity, cohesion, and SMF, exhibited a unimodal pattern—increasing initially and then declining at higher grazing levels. Linear regression and structural equation modeling indicated that grazing influences SMF mainly by modulating AMF community diversity and altering the complexity and stability of AMF networks. The effect of AMF community diversity on SMF was largely indirect, mediated through its effects on network structure, while its direct impact was relatively weak. Overall, this study highlights that the complexity and stability of AMF co-occurrence networks enhance the role of community diversity in shaping SMF and strengthen the interdependent relationship between biodiversity and ecosystem functioning. These findings offer valuable theoretical insights for the restoration and sustainable management of degraded grassland ecosystems.

Aims Soil organic carbon (SOC) is a crucial component for maintaining soil health and fertility in tea (Camellia sinensis) plantations, and its fixation process is closely associated with arbuscular mycorrhizal fungi (AMF). However, the response mechanisms of AMF community composition and SOC accumulation to magnesium (Mg) fertilization in tea plantations remain poorly understood.

Methods This study was conducted at a 7-year long-term experimental site in Anxi County, Fujian Province, within Tieguanyin tea plantations subjected to continuous Mg fertilization. Four application rates of magnesium sulfate heptahydrate (MgSO₄·7H₂O) application were implemented: Mg0 (0 kg·hm^-2, control), Mg50 (17.5 kg·hm^-2), Mg100 (35 kg·hm^-2), and Mg200 (70 kg·hm^-2). The research aims to elucidate the responses of both AMF communities and SOC content to Mg fertilization in the tea plantation ecosystem.

Important findings Compared to Mg0, Mg50, Mg100, and Mg200 significantly increased SOC content (by 7.8%, 11.7%, and 14.8%), exchangeable Mg²⁺ content (by 1 370%, 2 351%, and 2 746%), soil pH (by 2.3%, 2.8%, and 4.2%), dissolved organic carbon content (by 3.5%, 3.3%, and 4.0%), tea pruning biomass (by 6.1%, 13.9%, and 20.2%), and the relative abundance of the Glomus (by 59.5%, 75.4%, and 37.3%). Structural equation modeling revealed that magnesium fertilization promotes SOC sequestration synergistically through two main pathways: firstly, by improving soil physicochemical properties and stimulating tea plant growth to enhance carbon input; and secondly, by optimizing the AMF community structure and strengthening the functional contribution of Glomus. This study elucidates the dual-pathway mechanism through which magnesium fertilization enhances carbon sequestration in tea plantations by regulating the soil microenvironment and AMF communities, providing a theoretical foundation and practical strategies for achieving carbon neutrality in tea garden ecosystems.

Aims Plant invasions often lead to the loss of local species diversity and cause significant economic losses. The Enhanced Mutualisms Hypothesis, a widely recognized invasion mechanism, suggests that alien plant species capitalize on novel but strong soil mutualists, enhancing their success in invasion. In this study, the contributions of arbuscular mycorrhizal fungi (AMF) and litter to the growth strategy of invasive plant under different nutrient conditions were investigated.

Methods We inoculated AMF (Claroideoglomus etunicatum) and leaf litter to explore the roles of AMF-litter interactions in the responses of notorious invasive Solidago canadensis under varying nutrient conditions.

Important findings The results showed that litter addition significantly increased the mycorrhizal colonization rate and ratio of abundance class in S. canadensis. Under low-nutrient conditions, both AMF and litter promoted the stem length, leaf area and above-ground biomass, but significantly decreased the root-shoot ratio, and with the most pronounced synergistic enhancement observed in AMF-litter interactions. Under normal nutrient conditions, only AMF-litter interactions significantly inhibited the development of root system but increased the above-ground biomass in S. canadensis. Relative Interaction Intensity (RII) analysis further revealed that AMF and litter significantly stimulated above-ground growth, with stronger effects under low-nutrient conditions compared to normal nutrient levels. These findings suggest that S. canadensis could adjust the allocation strategies for aboveground-belowground resource by AMF-litter interactions to respond low-nutrient stress. This study provides novel insights into how invasive plant utilize symbiotic AMF and litter interactions to mediate resource allocation under nutrient heterogeneity, advancing our understanding of the mechanism underlying the successful invasion of alien plants.

Aims Arbuscular mycorrhizal fungi (AMF) can enhance the competitive ability of invasvie plant against native species, which is likely influenced by soil nitrogen (N) forms. In the context of increasing N deposition, exploring the effects of AMF on the growth and competitiveness of invasive plants under different forms of N addition can enhance our understanding of how invader adapts to soil N patterns shaped by N deposition.

Methods A common garden experiment was conducted using the invasive plant Bidens alba and the native species Emilia sonchifolia. The experimental design included two planting regimes (monoculture and mixture), three N treatments (ammonium nitrogen addition, nitrate nitrogen addition, and no N addition), and two microbial treatments (with or without AMF). By comparing the plant biomass, mycorrhizal growth responses, and competitive responses of total plant biomass among different treatments, this study explores the effects of different forms of N and AMF on the competitive ability of B. alba.

Important findings Under all N treatments, AMF significantly increased the biomass of the native plant E. sonchifolia. Specifically, when grown in monoculture with nitrate addition, AMF exhibited the greatest promoting effect on its biomass, indicating high mycorrhizal dependence in the native species, which is also influenced by soil N forms. AMF did not show a significant impact on the invasive plant B. alba under either monoculture or mixed planting. The greatest enhancement of the competitive response of B. alba by AMF occurred under no N addition, but no evidence was found that AMF could help the invasive plant adapt to different forms of nitrogen to maintain its competitiveness. This may be related to its strong mycorrhizal autoregulation ability. The results suggest that the invasive plant B. alba thrive under high N deposition conditions through direct nutrient uptake pathways and its mycorrhizal autoregulation ability. This study demonstrates that plant-AMF symbiosis is influenced by N addition and N forms, highlighting the importance of N forms in shaping the mycorrhizal responses of invasive plants and deepening our understanding of the role of AMF in growth and competitive response of invasive plants under future N deposition scenarios.

Aims Ectomycorrhizal trees obtain nitrogen (N) through direct root uptake from soil (root pathway) and via ectomycorrhizal fungal mycelia translocated to roots (mycelia pathway). However, the relative contribution of the mycelial pathway to tree N acquisition (f_fungi) remain highly uncertain, and the key influencing factors are not well defined in natural ecosystems.

Methods In this study, we employed the ¹⁵N natural abundance method to quantify the relative contribution of the mycelial pathway to N acquisition in two ectomycorrhizal trees (Abies fargesii var. faxoniana and Betula utilis) on the eastern Qingzang Plateau. We further analyzed the influencing factors of f_fungi.

Important findings Our results showed that the contribution of mycelia pathways to total N uptake was comparable to that of root pathways in both A. fargesii var. faxoniana and B. utilis. Specifically, the mycelia pathway contributed to 33.6%-71.8% of total N uptake in A. fargesii var. faxoniana and 41.6%-63.0% in B. utilis. Moreover, the soil carbon to nitrogen ratio, mean annual temperature and soil pH were identified as a key influencing factor for f_fungi. This study provides perspectives and insights for understanding N acquisition strategies and their influencing factors in ectomycorrhizal trees within natural ecosystems.

Aims Saline alkali land is an important reality and potential agricultural resource to solve the shortage of arable land in China. Efficient utilization of saline alkali land resources to develop peanut (Arachis hypogaea) planting in such environments and achieve high and stable yield has become an urgent demand for ensuring peanut production. Under saline alkali stress habitat, arbuscular mycorrhizal fungi (AMF) can effectively develop potential productivity of host plants and improve their salt resistance and tolerance. Although it has been demonstrated that AMF enhanced peanut salt tolerance under salt stress, however, there have been limited reports on the effects of AMF on the growth and development of salt-tolerant and salt-sensitive peanut.

Methods This study was investigated the response mechanisms of peanut growth and rhizosphere soil environment to AMF under saline-alkali conditions, aiming to provide theoretical basis and technical support for AMF application in peanut production in saline alkali soils. The experiment used salt-tolerant cultivar ‘HY25’ and salt-sensitive cultivar ‘HY22’ as experimental materials, with AMF seed coating treatment applied under saline alkali and normal soil conditions.

Important findings Under two soil conditions, salt-tolerant and salt-sensitive peanut cultivars demonstrated differential response mechanisms to AMF inoculation. Under both soil environments, AMF improved the agronomic characteristics in ‘HY25’, optimized photosynthetic parameters, and significantly increased pod yield. While AMF exhibited partial inhibitory effects on agronomic traits in ‘HY22’ in normal soil, it notably improved leaf photosynthetic performance and elevated both pod yield and quality. Significant differences were found in the response of root growth of two cultivars to AMF including: 1) In normal soil, the promoting effect of AMF on the growth of ‘HY25’ root system initiated during the flowering-pegging stage and continued to until maturation stage. Under saline-alkaline soil, AMF significantly increased total root length, root surface area, and root volume in ‘HY25’ at pod-setting stage. 2) Salt-sensitive cultivar ‘HY22’ exhibited greater sensitive to AMF inoculation. Under both normal and saline-alkali soils, AMF demonstrated inhibitory effects on root growth in ‘HY22’ during flowering-pegging and/or pod-setting stages, with significantly stronger inhibition observed under saline-alkali soil than normal soil. Moreover, AMF effects on rhizosphere soil properties included: 1) significant elevation in available phosphorus contents in both cultivars under two soil conditions; 2) increased soil catalase, phosphatase, and invertase activities in both cultivars in saline alkali soil; whereas 3) significant inhibition of soil enzymatic activities in ‘HY22’ under normal soil. These results indicated that compared to salt-sensitive cultivar, salt-tolerant cultivar might serve as more efficient symbiotic partner for AMF. AMF might demonstrate superior growth promotion in salt-tolerant cultivar, effectively exerting the synergistic effect of microbial regulation under saline-alkali soil.

Aims Legume-grass intercropping is an important strategy for restoring degraded grasslands and improving productivity in Southwest China. Arbuscular mycorrhizal fungi (AMF) play a key regulatory role in nutrient uptake within these systems. However, the mechanism by which AMF regulates nitrogen uptake and allocation in intercropping communities composed of plants with varying rooting depths remains unclear.

Methods Based on differences in nitrogen-fixing traits and root depths, this study selected a deep-rooted legume Medicago sativa and a shallow-rooted legume Trifolium repens, intercropped with two grass species, Dactylis glomerata and Lolium perenne. Monocultures and mixtures were established with or without AMF. Using ¹⁵N labeling at two soil depths 3 cm shallow and 25 cm deep, we explored the effects of AMF on the nitrogen acquisition strategies and community functions of plants with different root depths.

Important findings Intercropping significantly increased the total community of the plant community. The combination of T. repens + D. glomerata + L. perenne performed best, increasing yield by 54.78% and 76.58% compared to T. repens or L. perenne monocultures, respectively. This highlights a significant belowground niche complementarity between shallow-rooted legumes and grasses, which enhanced resource use efficiency. Conversely, the deep-rooted M. sativa showed spatial root overlap with grasses, intensifying interspecific competition and diminishing in insignificant intercropping advantages. AMF inoculation significantly promoted biomass accumulation in the strongly mycorrhizal-dependent legumes while moderating the competitive dominance of the less-dependent grasses, thereby increasing the legume proportion within the community. Furthermore, AMF induced plasticity in root morphology, significantly increasing the root length of T. repens and L. perenne.¹⁵N tracing revealed that intercropping promoted legume nitrogen fixation rates; AMF inoculation further strengthened this process and reduced the uptake of soil ¹⁵N by legumes. Meanwhile, AMF narrowed the difference in ¹⁵N uptake by grasses across soil layers, promoting more efficient utilization of deep-soil nitrogen. AMF achieved optimal resource allocation at the community level by enhancing legumes nitrogen fixation efficiency and promoting deep soil nitrogen acquisition by grasses. This study verifies that the shallow-rooted legume + grass mixture combined with AMF inoculation is the optimal strategy for achieving belowground spatial partitioning and high aboveground yield, providing a theoretical reference for the establishment of artificial grasslands in Southwest China.

Aims The semi-arid coal mining area of Ordos has long faced challenges such as poor soil fertility and difficulties in plant establishment. Microorganisms and plants are closely interconnected components of ecosystems. Arbuscular mycorrhizal fungi (AMF) can form mutualistic symbioses with plants and promote nutrient cycling within soil ecosystems. However, studies investigating the combined effects of AMF and different functional bacteria on soil properties and herbaceous plant growth remain limited. In this study, arbuscular mycorrhizal fungi were combined with three functional bacteria in various inoculation treatments and applied to the roots of alfalfa (Medicago sativa). The study evaluated their effects on improving the physicochemical properties of semi-arid soils in the Ordos coal mining area and their growth-promoting effects on plants.

Methods In this study, we combine arbuscular mycorrhizal fungi with three functional bacteria in multiple combinations to inoculate the alfalfa roots, investigate their improvement effects on the physicochemical properties of semi-arid soils in Ordos coal mining area and the growth-promoting effects on plants in the region.

Important findings Our results reveal that, compared with only growing alfalfa, the AMF + Rhizobium + Bacillus megaterium (ARB) system significantly enhanced the nutrient levels in the soil of alfalfa roots. Contents of soil organic matter, total nitrogen, and available phosphorous increased by 93.7%, 117.6% and 215.6%, respectively. This treatment also enhanced the stress resistance of plants and promotes its growth. The AMF infection rate in alfalfa roots increased by 76.9%, the primary roots increased by 53.2, the lateral root length increased by 8 cm, and the aboveground biomass of alfalfa increased by 168.0%. High-throughput sequencing results showed that in the ARB treatment, the relative abundances of the genera such as Sphingomonas, and Arthrobacterincreased, becoming dominant genera. These findings provide a scientific basis for addressing soil infertility and difficulties in plant establishment challenges in semi-arid mining areas.