搜索结果：Mycorrhiza

Although plant-mycorrhizal fungi associations play critical roles in maintaining species diversity within forest communities, the influence of tree ontogeny in mediating these effects on species diversity remains poorly understood. In this study, we integrated tree census data with information on the mycorrhizal types and sprouting ability of multi-stemmed species from a subtropical forest to assess how mycorrhiza-mediated neighborhood interactions affecting survival vary across ontogenetic stages (sapling, juvenile and adult stages) and how these effects correlate with sprouting ability. Our results revealed pervasive ontogenetic shifts in mycorrhiza-mediated neighborhood effects on tree survival for multi-stemmed species. AM heterospecific neighbors consistently exerted positive effects on tree survival across all life stages. In contrast, ErM heterospecific neighbors significantly influenced survival only at the sapling stage, whereas EcM heterospecific neighbors had significant effects during the juvenile and adult stages. When focal individuals were classified by mycorrhizal type, AM focal plants were significantly influenced by three types of mycorrhizal heterospecific neighbors, with the effect of AM heterospecific neighbors at the sapling stage being significantly greater than those of EcM or ErM heterospecific neighbors. Notably, AM heterospecific neighbors were critical predictors of survival for EcM focal plants during both the juvenile and adult stages, while AM and EcM heterospecific neighbors jointly the enhanced survival of ErM focal plants during the adult stage. Moreover, the effects of both AM and EcM heterospecific neighbors increased significantly with the sprouting ability of multi-stemmed species, particularly at the sapling stage. Our study highlights the importance of incorporating tree ontogeny and mycorrhizal symbiosis types into the assessment of factors contributing to species coexistence among long-lived organisms.

Drought is an increasingly important constraint on plant productivity, affecting agricultural yields, forest dynamics, and ecosystem functioning worldwide. Mycorrhizal symbioses formed by arbuscular (AM) and ectomycorrhizal (EcM) fungi are key regulators of plant responses to water limitation, influencing water acquisition, transport, and maintenance of plant water status at the soil-plant interface. This review synthesizes current knowledge of the mechanistic pathways through which mycorrhizal associations enhance plant drought tolerance. We distinguish between direct hydraulic contributions, including expanded soil exploration via extraradical hyphal networks, hyphal water uptake, redistribution, and modifications of rhizosphere hydraulic properties, and indirect physiological and biochemical effects, such as changes in root system architecture, regulation of aquaporins, osmotic adjustment, antioxidant capacity, and phytohormonal signaling. Particular emphasis is placed on structural and functional differences between AM and EcM symbioses. We examine how contrasting intraradical interfaces (i.e., arbuscules versus Hartig net) and extraradical networks influence water movement, plant hydraulic conductance, and whole-plant performance under drought. We assess the implications of these processes for agriculture and forestry, highlighting context-dependent fungal-plant compatibility, maintenance of diverse mycorrhizal communities, and management practices that preserve soil structure and mycorrhizal networks. Despite substantial evidence that mycorrhizal fungi improve plant performance under water deficit, their quantitative contributions to plant water transport and growth remain insufficiently resolved, particularly in EcM-dominated systems. Addressing these knowledge gaps will require integrative, multi-scale approaches linking molecular regulation, root and hyphal hydraulics, and ecosystem-level water fluxes. Such advances are critical for predicting vegetation responses to intensifying drought conditions under global change.

Short-rotation sugar beet (Beta vulgaris L.) cultivation in the Western Forest-Steppe of Ukraine is often accompanied by increased phytopathogenic pressure and impaired rhizosphere functioning, creating a need for biological tools to stabilize the plant-soil system. This study evaluated the effects of arbuscular mycorrhiza and an antagonistic microbial consortium on pathogen pressure, rhizosphere activity, yield, and technological quality of sugar beet under different crop rotations. Field experiments were conducted in 2023-2025 using a three-factor design that included rotation, mycorrhizal inoculation, and microbial inoculation. The highest phytopathogenic pressure was recorded in the maize-soybean-sugar beet rotation, where the cumulative frequency of dominant pathogens reached 94.0% and the root rot severity index in the control was 28.6%. Arbuscular mycorrhiza reduced disease development by 14.6-16.4%, whereas the antagonistic consortium reduced it by 25.6-27.9% relative to the control. Their combined application was most effective, decreasing root rot severity to 9.6-17.1% and increasing root colonization, available phosphorus, and dehydrogenase activity in the rhizosphere. The highest yield (80.5 t/ha) and sugar content (18.5%) were obtained in the soybean-winter wheat-sugar beet rotation under combined inoculation. AMF can improve phosphorus acquisition and mycorrhiza-induced tolerance, whereas antagonistic fungi can directly suppress soil-borne pathogens through competition, antibiosis, and mycoparasitism, their combined use may provide complementary protection in disease-conducive rotations. Overall, integrating arbuscular mycorrhiza with antagonistic microorganisms is a promising approach for reducing pathogen pressure and improving sugar beet performance in short-rotation systems.

In nature, some tree species interact with both arbuscular mycorrhizal (AM) Glomeromycotina fungi and ectomycorrhizal (ECM) Basidiomycota/Ascomycota fungi, and are termed dual mycorrhizal plants. Although the AM-upregulated genes and their functions have been well studied, those of ECM symbiosis remain unclear, despite their essential roles in forest ecosystems. Therefore, this study aimed to compare symbiosis-regulated downstream genes in the dual mycorrhizal model tree, Eucalyptus grandis, during fully developed AM and ECM symbioses. First, we conducted a comparative transcriptomic analysis and found a distinct transcriptional profile between E. grandis AM and ECM roots. Notably, none of the examined AM-related downstream genes were upregulated in the ECM roots. To identify ECM-specific genes and their expression patterns, comparative genomic analysis was performed. This study identified several gene families, including NAC transcription factors, that significantly expanded across the examined ECM lineages. Interestingly, we identified some ECM-promoted NAC transcription factors in the ECM roots of E. grandis, Populus trichocarpa, and Castanea mollissima. Moreover, none of the Eucalyptus NAC genes were transcriptionally promoted during AM symbiosis. Taken together, our results indicate that the downstream pathways necessary for the establishment of AM and ECM symbioses would be distinct.

This study evaluated ectomycorrhizal compatibility, functional effects, and the inoculum-dose response of Lactarius quieticolor and Tuber floridanum in Pinus elliottii and Pinus taeda, aiming to understand the role of fungus-host specificity in the expression of growth and physiological responses. Basidiomes of Lactarius spp. used as the inoculum source were identified through morphological and molecular analyses, confirming the identity as L. quieticolor. The symbiont L. quieticolor formed ectomycorrhizae on both Pinus species, whereas T. floridanum established an association only with P. elliottii, representing the first experimental record of this interaction. In P. elliottii, both fungi elicited integrated responses regardless of dose, with increases in growth, root biomass and electron transport rate, while L. quieticolor also increased root length, phosphorus content and modulated initial chlorophyll fluorescence. In P. taeda, effects were more limited and dose-dependent: increases in shoot nitrogen content, electron transport rate and root colonization were observed only at the highest inoculum concentrations. Multivariate analyses revealed a clear separation between control and inoculated plants even as the fungal treatments, indicating specific functional signatures. Altogether, the results demonstrate that ectomycorrhizal compatibility is not universal among congeneric Pinus species and highlight the potential of L. quieticolor and T. floridanum as functional ectomycorrhizal symbionts, with implications for seedling production and the ecology of forest systems.

Biochar (BC) and arbuscular mycorrhizal fungi (AMF) have emerged as powerful tools for sustainable agriculture, offering significant benefits for soil health, crop productivity, and ecological resilience. Their combined application has shown synergistic effects; however, key gaps in our understanding remain. This systematic review synthesizes findings from recent studies (n = 72) published up to 2025 to examine the synergistic effects of biochar and AMF. A comprehensive search across Scopus, Web of Science, and PubMed employed database-specific Boolean operators combining keywords such as "biochar," "mycorrhizal fungi," "soil health," and "nutrient cycling." This review highlights the role of biochar in improving soil structure, nutrient availability, and microbial diversity, thereby providing favourable habitats for mycorrhizal colonization. Approximately 78% of reviewed studies reported yield or nutrient-uptake improvements ranging between 15-35% under combined BC-AMF treatments, particularly under environmental stresses like drought or salinity. Synergistic interactions also promoted microbiome shifts, notably increasing the dominance of Glomus and Rhizophagus, which were associated with biochar porosity and nutrient composition. However, uncertainties remain regarding the long-term sustainability of these effects, and the influence of biochar properties on AMF functionality. To fully realize the potential of BC-AMF synergies, future research must focus on standardizing biochar production, exploring molecular and soil-plant-microbe mechanisms, and conducting long-term studies. Collaboration among stakeholders is essential to ensure the scalability and adoption of these technologies, positioning BC-AMF systems as ecologically sustainable alternatives that can support resilient agricultural production while reducing dependence on conventional chemical inputs.

The utilization of arbuscular mycorrhizal fungi (AMF) and phosphorus fertilizer can improve growth and physiological characteristics in plants. This study evaluated the effects of AMF and phosphorus levels on morpho-physiological characteristics of Quinoa and Maize under intercropping systems. The experiments were conducted at two locations, with three levels of phosphorus fertilizer [0 (P1), 50 kg ha-1 (P2), and 100 kg ha-1 (P3)], and AMF at two levels [inoculation M (+) and non-inoculation M (-)]. The results showed that the highest amounts of chlorophyll a (2.205/4.74 mg g-1 FW), chlorophyll b (0.75/2.88 mg g-1 FW), total chlorophyll (3.5/8.28 mg g-1), were achieved in a 50:50 intercropping ratio of Maize and Quinoa, under M (+) and P2 application. The results showed that the highest seed yield of Quinoa (2542 kg ha-1) was obtained under mycorrhizal and 50 kg ha-1 phosphorus application in the Shahrood location. Additionally, the highest total dry weight (TDW) in Maize (418.85 g m-2) was achieved with M (+), while the highest TDW of Quinoa (295.65 g m-2) was obtained in solo culture. The highest leaf area index (LAI) of Maize was obtained for sole culture, use of phosphorus 50 kg ha-1, and M (+). The highest Quinoa LAI was obtained in different cropping ratios, with the highest value of 8.52 in 50% Quinoa. The net assimilation rate in Quinoa reached the maximum (7.2 g m-2 day-1) at 45 days after sowing, while in Maize, the maximum of NAR (10.2 g m-2 day-1) was reached at 75 days after sowing. The mean comparison of traits revealed that the highest Quinoa colonization (46.29%) was achieved with a 25% Quinoa and 75% Maize cropping ratio, and a phosphorus concentration of 50 kg ha-1, using arbuscular mycorrhizal fungi (AMF). These findings suggest that AMF application in an intercropping ratio of 50:50 may be proposed to farmers as an eco-friendly approach to achieve desirable physiological characteristics.

Aluminum (Al) toxicity is a critical environmental factor limiting plant productivity in acidic soils. Some ectomycorrhizal fungi (ECMF) can mitigate Al-induced stress and promote root growth in Pinus massoniana Lamb., however the underlying molecular and metabolic mechanisms have not yet been fully elucidated. In this study, P. massoniana seedlings inoculated with Lactarius deliciosus (L.) Gray (Ld) were subjected to acidic Al stress (pH 3.8) at Al3+ concentrations of 0.0 and 1.0 mM. Root growth, transcriptomic, metabolic and hormonal characteristics of the mycorrhizal symbionts were determined and analyzed. The study aimed to identify the key metabolites and metabolic pathways involved in ECMF-enhanced Al stress tolerance of P. massoniana, and to further elucidate on the underlying mechanism of ECMF in improving the Al resistance of P. massoniana from molecular and metabolic-physiological perspectives. Results showed that Ld inoculation significantly enhanced Al tolerance and promoted root growth and branching in P. massoniana. Specifically, it activated the phenylpropanoid-lignin biosynthesis pathway in mycorrhizal symbionts, downregulated carbon metabolism pathways and reduced intracellular accumulation of citric acid and specific amino acids (L-proline, L-threonine, serine). Furthermore, Ld elevated salicylic acid and gibberellin levels, decreased jasmonic acid content, upregulated growth-promoting genes (MYC2, GH3, TCH4) and downregulated inhibitory genes (ARF9/19, DELLA). This study further refines and clarifies the mechanism underlying ECMF-enhanced Al resistance in P. massoniana, and provides a theoretical basis for the application of ECMF in the ecological restoration of P. massoniana forest areas affected by Al toxicity.

Different AMF species regulate soil nitrogen transformation by guiding divergent cotton carbon investment strategies. Moderate inoculation with Acaulospora scrobiculata achieves optimal nitrogen benefits at minimal carbon cost. Arbuscular mycorrhizal fungi (AMF) form symbioses with most terrestrial plants, enhancing phosphorus and nitrogen uptake. However, the mechanisms by which different AMF species and inoculation dosages synergistically regulate host nitrogen uptake efficiency remain insufficiently elucidated. This study investigated three AMF species-Glomus heterosporum (Gh), Acaulospora scrobiculata (As), and Paraglomus occultum (Po)-at different inoculation dosages (440, 880, and 1320 spores g-1) on cotton growth, nitrogen uptake, plant carbon-to-nitrogen ratio, soil organic carbon input via hyphae, and soil enzyme activities. AMF significantly reduced soil organic carbon content and plant carbon-to-nitrogen ratio, altered soil enzyme activities, alleviated soil microbial nitrogen limitation, and promoted cotton growth and nitrogen uptake. At the moderate inoculation dosage (880 spores g-1), As exhibited the strongest promoting effect, increasing soil nitrogen acquisition-related enzyme activities by 103.7%, and enhancing shoot and root nitrogen accumulation by 3.46-fold and 2.40-fold, respectively. It effectively drives soil nitrogen transformation processes by guiding a moderate allocation of plant carbon. Gh exhibited the highest mycorrhizal nitrogen response at the high inoculation dosage (1320 spores g-1), but its carbon flow had limited stimulatory effects on nitrogen transformation. In contrast, the growth-promoting effect of Po and its ability to regulate soil nitrogen transformation were weaker. Furthermore, the AMF colonization rate was positively correlated with the mycorrhizal nitrogen and growth response, but negatively correlated with the input of soil organic carbon via the hyphal pathway. This study elucidates how carbon investment strategies directed by different AMF species regulate soil nitrogen transformation, supporting sustainable, AMF-based fertilization strategies in cotton cultivation.

With escalating global health challenges, triclocarban (TCC) contamination has reemerged as a critical ecological threat, especially in wetland ecosystems. Yet, the mechanisms by which arbuscular mycorrhizal fungi (AMF) regulate plant root resistance and the rhizosphere environment under TCC exposure remain poorly understood. Here, we established an AMF-Phragmites communis symbiotic system and conducted TCC exposure experiments. Our results demonstrated that TCC exposure significantly inhibited mycorrhizal colonization, root morphology, and the antioxidant system of P. communis. Specifically, under the 5 mg kg- 1 soil TCC exposure, arbuscule abundance decreased by 3.53-fold, root total length declined to 1011.13 cm, and the integrated biomarker response index value of the antioxidant system dropped to 0.25. In contrast, arbuscular mycorrhizal (AM) symbiosis promoted root morphological and physiological growth. Transcriptome analysis revealed that AM symbiosis upregulated genes encoding key enzymes in the Mitogen-Activated Protein Kinase (MAPK) signaling pathway (e.g., MAPKKK and MAPK family members), whereas TCC exposure downregulated their expressions. Furthermore, in the rhizosphere soil, the composition and structure of microbial communities were distinctly influenced by AM symbiosis and TCC exposure. Compared to AM symbiosis, which upregulated soil metabolites associated with metabolism, TCC exposure downregulated soil metabolites across multiple functional categories, including metabolism, environmental information processing, and cellular processes. This research broadens our understanding of how AM symbiosis enhances the resistance of P. communis and maintains the stability of the rhizosphere environment under TCC exposure, and evidences the potential of AMF application in improving the purification capacity of wetland systems.

Plant growth-promoting microorganisms (PGPMs) and biochar are increasingly recognized as sustainable strategies to enhance crop performance; however, their comparative and integrative effects on carbon-water coordination and leaf thermal regulation under soilless substrate conditions remain poorly resolved. We investigated the physiological responses of Vigna radiata L. to bacterial biostimulant (BB), arbuscular mycorrhizal (AM) fungi, their co-inoculation (BA), and BA combined with biochar (BiB). All treatments enhanced biomass relative to the uninoculated control, but through distinct physiological mechanisms. BB reduced leaf temperature (LT) primarily via increased stomatal conductance and transpiration, supporting higher net photosynthesis. In contrast, AM enhanced plant water status, as reflected by higher relative water content, and maintained intrinsic water-use efficiency comparable to the control but greater than in the other inoculation treatments. The reduction in LT under AM, despite unchanged transpiration, may reflect differences in plant water relations rather than purely evaporative cooling. BA integrated these complementary functions, resulting in the lowest LT, and maximum biomass. BiB further enhanced photosynthetic rate and maintained intrinsic water-use efficiency, although biomass was slightly lower than in BA. Collectively, the results demonstrate that the distinct physiological roles of bacterial and mycorrhizal inoculants, stomatal-driven carbon acquisition versus hydraulic stabilization, become functionally complementary under co-inoculation, enabling coordinated regulation of carbon assimilation, water balance, and leaf thermal dynamics to maximize biomass production. By reducing leaf temperature, PGPMs could contribute to maintaining photosynthetic efficiency under potential heat stress.

Most terrestrial plants can establish symbiotic relationships with arbuscular mycorrhizal (AM) fungi, which increase the host plants' resilience to pathogens. The effect of pre-inoculation with AM fungi as a bio-agent on lettuce (Lactuca sativa L.) plant resistance against Alternaria alternata RaSh3 leaf spot disease was investigated. The findings demonstrated that in A. alternata-infected plants, AM fungi could effectively colonize lettuce roots at a higher rate (100%) than in non-infected plants (91.66%). According to the disease assessment, lettuce plants pre-inoculated with AM and infected with A. alternata RaSh3 showed a 33.33 and 30.00% reduction in disease incidence and severity, respectively. During A. alternata RaSh3 infection, the primary growth responses, pigment fraction, proline, and carbohydrates of lettuce plants were reduced, accompanied by increases in oxidative stress markers [malondialdehyde (87%) and hydrogen peroxide (30.8%)]. Contrarily, AM-inoculated plants showed a significant increase in growth, photosynthetic pigments, osmolytes and enzymatic and non-enzymatic antioxidant enzymes either in A. alternata RaSh3-infected or non-infected ones. Overall, our results highlight the significance of AM fungi in alleviating infection symptoms by increasing proline (13%), flavonoids (28.3%), and phenolic compounds (44.7%). Moreover, a boost in the enzymatic status (phosphatases, antioxidants, and phenylalanine ammonia-lyase) was detected in A. alternata RaSh3-infected plants due to AM inoculation, proving the essential role of its inoculation in increasing plant resistance against A. alternata RaSh3. Finally, this experiment has proved the sustainable defense strategy of mycorrhizal symbiosis as a new bio-agent for the biological control of A. alternata in lettuce plants.

Ericoid mycorrhizal (ErM) fungi play a crucial role across terrestrial ecosystems, forming mutualistic symbiosis with Ericaceae and contributing to soil organic matter dynamics. However, compared to other fungal groups, their biogeography remains unknown. Here, we combined several analytical approaches to analyze a newly compiled, large-scale dataset comprising 39 163 soil samples and more than 13 million ITS rRNA sequences assigned to ErM fungi. Specifically, we asked: What are the global patterns of ErM fungal species richness and relative abundance (out of all fungi) and their predictors, and how is the distribution of ErM fungi associated with soil carbon content at the global scale? We show that ErM fungi reach their highest species richness in very high latitudes. Soil chemistry is a stronger predictor of ErM fungal species richness than climate or ericoid vegetation cover. The relative abundance of ErM fungi is highest in soils with high surface carbon content, supporting their proposed role in soil carbon storage. Furthermore, we predict that climate change will reduce ErM fungal abundance across 38% of the land cover of their current global distribution. Our study shows distinct biogeographic patterns of ErM fungi compared with arbuscular and ectomycorrhizal fungi and indicates the vulnerability of ErM fungi to climate change.

Avocado is a crop that requires edaphic and environmental sustainability for its production and is related to the increasing depletion of natural resources. To ameliorate the situation, microorganisms that promote plant growth allow us to achieve sustainability goals, functioning as complementary to inorganic fertilizers, and representing an alternative to the high costs of these inputs. In this study, a soilless culture of avocado rootstocks was established, and the effects of nutrient concentration in vegetative tissue, growth, and root development were evaluated by inoculation with arbuscular mycorrhiza-forming fungi, plant growth-promoting rhizobacteria, and phosphate rock applied in the seed stage. The study was conducted in a greenhouse using a disinfected substrate (perlite and agricultural foam) with a 23 factorial experimental design and evaluated at 103 DAS. Treatments with bacteria consisted of a consortium of P. tolassii (A46, P61), B. pumilus (R44-DsRed), and A. xylosoxidans (C56), inoculated directly into each seed. The AMF species were R. intraradices and were inoculated through a trap culture. Greater length and root volume were obtained by inoculation with PGPR, and less than 10% mycorrhizal colonization was obtained, which was insufficient to stimulate growth in seedlings; higher concentrations of N, P, and K in vegetative tissue were obtained, which were related to PGPR inoculation and RF application. Regarding height, the best results were obtained with AMF, PGPR, and PR treatment. In addition, the most abundant colonization with fluorescent bacteria was observed in this treatment. In conclusion, microorganism inoculation favored the development of avocado seedlings and improved root development and architecture.

Manganese (Mn) toxicity, exacerbated by soil acidification and anthropogenic pollution, poses a significant threat to plant growth and ecosystem health, particularly in economically important citrus plants. This study tried to uncover the mechanisms by which the arbuscular mycorrhizal fungus Funneliformis mosseae enhances Mn tolerance in trifoliate orange (Poncirus trifoliata) seedlings under excess Mn stress (20 mmol/L MnSO4). Although Mn stress inhibited root colonization by F. mosseae, inoculation with F. mosseae significantly alleviated the Mn-induced suppression of plant growth, root system architecture, photosynthetic efficiency, and photochemical activity of photosystem II. Crucially, AMF colonization reduced Mn accumulation in leaves, stems, and roots, alongside decreased the Mn bioconcentration and translocation factors. Mechanistically, F. mosseae enhanced Mn tolerance in trifoliate orange through two complementary strategies: external exclusion and internal detoxification. Externally, F. mosseae increased levels of difficultly extractable glomalin-related soil protein to sequestrate Mn in the rhizosphere, and significantly upregulated fungal suppressor of mitochondrial fission genes (FmSMF1 and FmSMF2) to enhance hyphal sequestration, thereby blocking Mn entry into roots. Internally, F. mosseae modulated the subcellular distribution and chemical forms of Mn in trifoliate orange: they promoted Mn compartmentalization into the cell wall and soluble (vacuolar) fractions, while reducing its accumulation and proportion in sensitive organelles such as chloroplasts and mitochondria. Furthermore, Mn was transformed from highly active, toxic forms (ethanol- and water-extractable) into more stable, inert forms (e.g., pectate- and phosphate-bound). Consistent with the reduced Mn uptake and toxicity, the expression of host metal tolerance protein (PtMTP8 and PtMTP11) and superoxide dismutase (PtMnSOD) genes was significantly downregulated in mycorrhizal roots under Mn toxicity. In conclusion, F. mosseae enhances Mn tolerance in trifoliate orange through a synergistic dual mechanism, establishing an external barrier via fungal-mediated immobilization and building an internal defense line by reprogramming host Mn compartmentalization and detoxification pathways, thereby minimizing Mn phytotoxicity.

The impact of arbuscular mycorrhiza fungi (AMF) on root-shoot scaling strategies under zinc and phosphorus deficiency remains poorly understood in maize. The aims of this study were (i) To quantify the effects of zinc/phosphorus deficiency on AMF colonization, (ii) to quantify biomass accumulation in different plant parts in the presence of AMF, and (iii) to characterize how AMF alter root-shoot allometric scaling under zinc/phosphorus deficiency. We conducted a pot experiment arranged in RCBD split plot with 6 replications. SUWAN 5819 maize seeds were grown for 22 days under five Hoagland's solution-based nutrient regimes (+Zn+P, -Zn-P, +Zn-P, -Zn+P, and deionized water), with and without AMF. AMF colonization was highest (49.6%) under -Zn+P contrary to hypothesis 1 which predicted highest colonization under dual deficiency, while the deionized water treatment had the lowest colonization (30.1%). Phosphorus was the dominant factor affecting biomass accumulation with a 2-4-fold reduction in organ dry weights for phosphorus-deficient treatments compared to phosphorus-sufficient treatments. AMF colonization significantly reduced dry weights in +Zn+P by 8.6%, 19.0%, and 47.5% in the leaf, stem, and roots, respectively, consistent with mycorrhiza-induced growth depression (MGD). Nutrient deficiency resulted in root biomass accumulation, consistent with the optimal partitioning theory. AMF increased shoot mass fraction from 50% to 63% in +Zn+P, and from 41% to 52.5% in -Zn-P, suggesting AMF role in modulating biomass accumulation. Root-shoot scaling slopes derived from LMM revealed that zinc deficiency caused negative scaling trajectory, and AMF was associated with positive root-shoot scaling trajectory in the -Zn+P treatment, though the scaling relationship was not confirmed by SMA analysis. These findings highlight nutrient specific AMF-mediated growth dynamics in early vegetative stage.

Phosphorus (P) fixation in aerobic rice cultivation severely limits crop productivity. However, the mechanisms by which arbuscular mycorrhizal fungi (AMF) regulate phosphate transporter (OsPT) gene expression across genetically diverse varieties under variable soil P regimes remain poorly understood. A controlled pot experiment was conducted to examine six aerobic rice genotypes, CR Dhan 201, CR Dhan 204, CR Dhan 205, CR Dhan 207, IR 36 (P-susceptible), and Kasalath IC459373 (P-tolerant), under three soil P levels (low: 2.68 ppm, medium: 8.81 ppm, and high: 12.84 ppm) with and without AMF inoculation. AMF colonization was significantly higher (50.19-63.63%), and sporulation was greater (24.29-30.28 spores per 50 g soil) in CR Dhan 204, CR Dhan 205, and CR Dhan 207 under low and medium soil P. All AMF-inoculated varieties showed 33-55% improvement in root architecture and 14.87-50.22% higher P uptake compared to uninoculated controls under P-deficient conditions. Ten of the 13 phosphate transporter genes (OsPT2, OsPT3, OsPT4, OsPT6, OsPT8, OsPT9, OsPT10, OsPT11, OsPT12, and OsPT13) were upregulated in CR Dhan 207 under low soil P conditions with AMF, and the broadest gene activation profile was observed across all varieties. These findings establish that AMF-mediated regulation of the OsPT gene network is strongly variety-dependent and most pronounced under P-limited conditions, positioning CR Dhan 207 as a priority genotype for mycorrhiza-assisted phosphorus management in aerobic rice systems.

Arbuscular mycorrhizal fungi (AMF), in the phylum Glomeromycota, form symbiotic relationships with most vascular plants, including grasses. Tallgrass prairies (TGPs) are an endangered habitat in Ontario; some undisturbed fragments remain and there have been efforts to restore disused agricultural land to prairie. The objective of this study was to investigate differences in the community composition of arbuscular mycorrhizal fungi between disturbed and undisturbed TGP at five locations across southwestern Ontario. The V4 variable region of the small ribosomal subunit was amplified from DNAs extracted from soil samples, and sequence analysis yielded operational taxonomic units (OTUs) representing twelve genera of Glomeromycota. There was a significant difference in the community composition of the AMF communities in undisturbed TGP remnants and restored TGP that had been previously disturbed, with an overall greater community diversity and evenness in the undisturbed than previously disturbed sites. Ambispora fennica, three OTUs of Diversispora and four OTUs of Glomus were found to be potential indicator taxa of undisturbed TGPs and, overall, Glomus was significantly more abundant in undisturbed than disturbed sites. In contrast, two other OTUs of Diversispora, two of Entrophospora and one of Septoglomus were found to be potential indicator taxa of disturbed TGPs. These findings have implications for success of TGP restoration and should be considered in future efforts.

Arbuscular mycorrhizal (AM) and root nodule (RN) symbiosis play essential roles in plant nutrient acquisition and share a common symbiotic signal transduction pathway, yet they produce distinct developmental outcomes. Here, we identify arbuscular mycorrhiza-induced kinase 2 (AMK2), a leucine-rich repeat receptor-like kinase (LRR-RLK) in Lotus japonicus, as a key regulator of AM symbiosis. AMK2 is a paralog of the rhizobial infection receptor Rhizobial Infection Receptor-like Kinase 1 (RinRK1), highlighting an evolutionary link between receptors controlling different symbiotic programs. AMK2 expression is strongly induced following AM fungal (AMF) inoculation and is directly activated by the AM-specific transcription factor CBX1 through conserved CTTC cis-regulatory motifs. The AMK2 protein localizes specifically to arbuscule-containing cells, and amk2 mutants exhibit severely reduced arbuscule formation. Domain-swapping experiments between RinRK1 and AMK2 demonstrate that symbiosis specificity is determined by their intracellular kinase domains, whereas their extracellular domains are functionally interchangeable. Together, our findings show that two evolutionarily related LRR-RLK receptors have been differentially recruited to regulate AM and RN symbioses, providing mechanistic insights into how shared signaling components have diversified to control distinct mutualistic interactions between plants and microbes.