Tobacco is a significant economic crop cultivated in various regions of China. Arbuscular mycorrhizal fungi (AMF) can establish a symbiotic relationship with tobacco and regulate its growth. However, the influences of indigenous AMF on the growth and development of tobacco and their symbiotic mechanisms remain unclear. In this study, a pot inoculation experiment was conducted, revealing that six inoculants - Acaulospora bireticulata(Ab), Septoglomus viscosum(Sv), Funneliformis mosseae(Fm), Claroideoglomus etunicatum(Ce), Rhizophagus intraradices(Ri), and the mixed inoculant (H) - all formed stable symbiotic relationships with tobacco. These inoculants were found to enhance the activities of SOD, POD, PPO, and PAL in tobacco leaves, increase chlorophyll content, IAA content, CTK content, soluble sugars, and proline levels while reducing malondialdehyde content. Notably, among these inoculants, Fm exhibited significantly higher mycorrhizal infection density, arbuscular abundance, and soil spore density in the root systems of tobacco plants compared to other treatments. Membership function analysis confirmed that Fm had the most pronounced growth-promoting effect on tobacco. The transcriptome analysis results of different treatments of CK and inoculation with Fm revealed that 3,903 genes were upregulated and 4,196 genes were downregulated in the roots and stems of tobacco. Enrichment analysis indicated that the majority of these genes were annotated in related pathways such as biological processes, molecular functions, and metabolism. Furthermore, differentially expressed genes associated with auxin, cytokinin, antioxidant enzymes, and carotenoids were significantly enriched in their respective pathways, potentially indirectly influencing the regulation of tobacco plant growth. This study provides a theoretical foundation for the development and application of AMF inoculants to enhance tobacco growth.

Arbuscular mycorrhizal (AM) fungi are important plant symbionts that provide plants with nutrients and water as well as support plant defences against pests and disease. Consequently, they present a promising alternative to using environmentally damaging and costly fertilisers and pesticides in agricultural systems. However, our limited understanding of how agricultural practices impact AM fungal diversity and functions is a key impediment to using them effectively in agriculture. We assessed how organic and conventional agricultural management systems shaped AM fungal communities. We also investigated how AM fungal communities derived from these agricultural management systems affected crop biomass and development. Six soil samples from five organically and five conventionally managed agricultural sites were used to cultivate Sorghum bicolor. Plant growth, plant nutrient concentrations and AM fungal colonisation rates were analysed alongside DNA metabarcoding of community composition. We observed that soil from conventional agricultural fields resulted in a pronounced reduction in sorghum biomass (-53.6%) and a significant delay in flowering compared to plants grown without AM fungi. Sorghum biomass was also reduced with soil from the organic system, but to a lesser extent (-30%) and without a delay in flowering. Organic systems were associated with a large proportion of AM fungal taxa (50.5% of VTs) not found in conventional systems, including Diversispora (r(2) = 0.09, p < 0.001), Archaeospora (r(2) = 0.07, p < 0.001) and Glomus (r(2) = 0.25, p < 0.001) spp., but also shared a large proportion of taxa with conventional systems (42.3% of VTs). Conventional systems had relatively few unique taxa (7.2% of VTs). Our results suggest that conventional agricultural practices selected against AM fungi that were, in this context, more beneficial for host plants. In contrast, organic management practices mitigate this negative effect, likely due to the presence of specific key AM fungal taxa. However, this mitigation is only partial, as less beneficial AM fungal taxa still persist, probably due to abiotic factors associated with agricultural management and the sensitivity of AM fungi to these factors. This persistence explains why the effect is not entirely eradicated. Read the free Plain Language Summary for this article on the Journal blog.

Hordeum jubatum L. is a perennial herb with high ornamental value and strong stress tolerance. Nitrogen deposition and cold stress are key environmental factors that affect stability of ecosystems in cold regions of northeast China. These factors significantly affect plant growth and development. Arbuscular mycorrhizal fungi (AMF) are symbiotic soil fungi that can increase plant resistance and growth. However, research on impacts of nitrogen deposition and cold stress on roots of H. jubatum-AM symbionts remains limited. Root biomass (dry and fresh weight), architecture (length, surface area, volume, forks, number of fourth-order roots, and root fractal dimension), and ultrastructure of H. jubatum were assessed, both in the presence and absence of AMF, under conditions of nitrogen deposition and cold stress. Cold stress inhibited all indicators of root architecture and disrupted root ultrastructure, with greater inhibition shown in the N2 (NH4+/NO3- = 1:1) treatment under cold stress, indicating nitrogen deposition increased sensitivity of H. jubatum to cold stress. Inoculation with AMF significantly reduced damage caused by nitrogen deposition and cold stress on H. jubatum roots compared with the non-inoculation treatment. Our results demonstrate different effects of the interaction of nitrogen deposition and cold stress versus single stress (nitrogen deposition or cold stress) on plant root development and provide a scientific basis for the use of mycorrhizal technology to improve resistance and productivity of cold-tolerant plants in cold regions under stress conditions.

Root mechanical traits, including load for failure in tension (Fr), tensile strength (Tr), tensile strain (epsilon r), modulus of elasticity (Er), and tensile toughness (Wr), are critical for plant anchorage and soil stability. These traits are shaped by root morphology, type (absorptive and transport roots), and mycorrhizal associations (arbuscular mycorrhizal and ectomycorrhizal fungi). This study investigates the relationships among these traits. We examined mechanical traits across eight woody species with different mycorrhizal associations, categorizing roots into absorptive and transport types. Root morphological traits - root diameter (RD), specific root length (SRL), root tissue density (RTD), and root biomass (RB) - were measured. Tensile tests were conducted to assess mechanical properties. Statistical analyses, including regression and principal component analysis (PCA), were used to elucidate trait relationships. Transport roots exhibited superior mechanical properties compared to absorptive roots, with RD and RB showing significant positive correlations with mechanical traits. AM roots demonstrated higher tensile strength, strain, and toughness than EM roots. PCA highlighted RD and SRL as dominant factors influencing root mechanical performance, while RB contributed significantly to transport roots' structural stability. This study underscores the critical role of root morphological traits and mycorrhizal associations in determining mechanical performance. These findings highlight the ecological trade-offs between mechanical stability and resource acquisition, offering novel insights into root functional strategies and their implications for ecosystem stability.

This study investigates the role of arbuscular mycorrhizal fungi (AMF) in the metabolism of hexabromocyclododecane (HBCD) and its ecological effects in contaminated environments. We focused on the symbiotic relationships between Iris pseudacorus L. and AMF (Rhizophagus irregularis) under HBCD exposure. Our results show that HBCD induces oxidative damage, which hinders plant growth. However, AMF significantly enhance the plant's antioxidant defenses, reducing oxidative damage and supporting better growth of I. pseudacorus. HBCD biodegradation patterns showed beta- > gamma- > alpha-HBCD, with AMF playing a key role in stabilizing rhizosphere microbial communities, particularly promoting Proteobacteria and potential bacterial degraders like Aeromonas and Trichococcus, which contributed to HBCD removal. Additionally, AMF appear to upregulate genes such as cypD_E, GST, dehH, dehA, dehM, Em3.8.1.2, and ligB, which are involved in debromination and hydroxylation reactions. This research highlights AMF's potential to enhance the phytoremediation of HBCD, providing valuable insights for environmental remediation strategies.

Under saline-alkali stress conditions, inoculation with Rhizophagus irregularis or the application of biochar can both promote plant growth and improve soil physicochemical properties. However, the effects of their combined use on switchgrass growth and soil mechanical properties remain unclear. This study established four treatments: no Ri inoculation and no biochar addition (control, CK), biochar addition alone (BC), Rhizophagus irregularis inoculation alone (Ri), and their combination (RB). The aim was to investigate the effects of these treatments on the biomass, root morphology, and soil mechanical properties of switchgrass under saline-alkali stress. The results showed that compared to the CK treatment, the RB treatment significantly increased the root, stem, leaf, and total biomass of switchgrass by 67.55%, 74.76%, 117.31%, and 82.93%, respectively. Among all treatment groups, RB treatment significantly reduced soil bulk density, soil water-soluble sodium ions (Na+), soil exchangeable sodium percentage (ESP), and sodium adsorption ratio (SAR), while increasing soil porosity. Furthermore, RB treatment significantly improved infiltration rate and shear strength. Compared to the CK treatment, the stable infiltration rate and shear strength under 400 kPa vertical load increased by 70.69% and 22.5 kPa, respectively. In conclusion, the combination of Ri and biochar has the potential to improve soil mechanical properties and increase the biomass of switchgrass under saline-alkali stress.

Salt accumulation can degrade soil properties, decrease its productivity, and harm its ecological functions. Introducing salt-tolerant plant species associated with arbuscular mycorrhizal fungi (AMF) can act as an effective biological method for restoring salinized soils. AMF colonize plant roots and improve their nutrient acquisition capacity. However, there is limited knowledge on how AMF affects the production of signaling molecules, e.g., abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), related to plant-microbe interactions under salinity. Here, we assess the potential benefits of the AMF Rhizophagus intraradices in enhancing plant growth and nutrient uptake in addition to modulating stress hormone signaling levels (ABA, SA, and JA) of the facultative halophyte Sulla carnosa under saline conditions. Plants were grown in pots filled with soil and irrigated with 200 mM NaCl for 1 month. AMF symbiosis substantially increased the shoot dry weight (+107%), root dry weight (+67%), photosynthetic pigment content (chlorophyll a, chlorophyll b, and carotenoids), and nutrient uptake (C, N, P, K, Cu, and Zn) while significantly limiting the increase in the shoot Na+ concentration and H2O2 content caused by salinity stress. Mycorrhizal symbiosis significantly enhanced the root and shoot SA levels by 450% and 32%, respectively, compared to the stressed non-inoculated plants, potentially contributing to enhanced systemic resistance and osmotic adjustment under saline conditions. Salt stress increased the shoot ABA content, especially in R. intraradices-inoculated plants (113% higher than in stressed non-mycorrhizal plants). These findings confirm that AMF mitigated the adverse effects of salinity on S. carnosa by increasing the SA and ABA levels and reducing oxidative damage.

Salinity stress significantly impacts agricultural productivity by damaging key plant mechanisms like photosynthesis, osmotic balance, and enzymatic activity. Withania somnifera (L.) Dunal, valued in Ayurveda for its anti-carcinogenic withanolides such as withaferin A, faces reduced yields due to soil salinity in India. Sustainable, eco-friendly methods are needed to mitigate salt stress and improve economic yield, as conventional approaches are environmentally unsustainable for long-term productivity. This study hypothesizes that plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) could effectively reduce salinity stress and enhance withaferin A production. The study evaluates the effects of nitrogen-fixing bacteria (Azotobacter chroococcum), phosphate-solubilizing bacteria (Bacillus amyloliquefaciens), potassium-solubilizing bacteria (Enterobacter esburiae), and a mycorrhizal consortium under saline (4.5 dS m-1) and non-saline conditions. The 4.5 dS m-1 sodium chloride salinity dose significantly (p < 0.05) reduced growth attributes and increased malondialdehyde (p < 0.001) (MDA) content, electrolytic leakage (p < 0.0001) (EL), and sodium-potassium ratio (p < 0.001) by 113.38%, 79.51%, and 114.85%, respectively, compared to control. Among all the biofertilizer treatments, AMF inoculation most effectively improved (p < 0.05) growth parameters and decreased MDA (p < 0.01), EL (p < 0.001), and sodium-potassium ratio (p < 0.0001) by 69.99%, 21.42%, and 66.96%, respectively. Under salinity stress, AMF inoculation maximally increased (p < 0.0001) withaferin A by 49.07%, while PGPB increased (p < 0.05) it upto 34.54%. The findings suggest that AMF and PGPB alleviate salinity stress by reducing lipid peroxidation and electrolyte leakage, regulating the sodium-potassium ratio, and enhancing withanolide production in W. somnifera. Thus, microbial inoculation offers a sustainable, eco-friendly approach to improving the growth and yield of secondary metabolites in W. somnifera in salt-affected regions.

Cadmium (Cd) is a highly toxic agricultural pollutant that inhibits the growth and development of plants. Arbuscular mycorrhizal fungi (AMF) can enhance plant tolerance to Cd, but the regulatory mechanisms in Allium fistulosum (green onion) are unclear. This study used a Cd treatment concentration of 1.5 mg center dot kg-1, which corresponds to the risk control threshold for soil pollution in Chinese agricultural land, to examine the effects and molecular mechanisms of AMF inoculation on the growth and physiology of green onion under Cd stress. AMF formed an effective symbiotic relationship with green onion roots under Cd stress, increased plant biomass, improved root structure and enhanced root vitality. AMF-colonized green onion had reduced Cd content in roots and leaves by 63.00 % and 46.50 %, respectively, with Cd content being higher in the roots than in the leaves. The ameliorative effect of AMF on Cd toxicity was mainly due to a reduction in malondialdehyde content in leaves (30.12 %) and an enhancement of antioxidant enzyme activities (peroxidase, catalase, superoxide dismutase, glutathione reductase and reduced glutathione) that mitigated damage from excessive reactive oxygen species. In addition, AMF induced secretion of easily extractable glomalin soil protein and total glomalin-related soil protein and inhibited the translocation of Cd to the shoots. Transcriptomic and metabolomic correlation analyses revealed that differentially expressed genes and metabolites in AMF-inoculated green onion under Cd stress were predominantly enriched in the phenylpropanoid biosynthesis and phenylalanine metabolism pathways, upregulated the expression of the HCT, PRDX6, HPD, MIF, and HMA3 genes, and accumulation of the phenylalanine, L-tyrosine, and 1-O-sinapoyl-beta-glucose metabolites. Thus, AMF enhance Cd tolerance in green onions by sequestering Cd in roots, restricting its translocation, modulating antioxidant defenses and inducing the expression of genes involved in the phenylpropanoid biosynthesis and phenylalanine metabolism pathways. Collectedly, we for the first time revealed the mechanism of AMF alleviating the toxicity of Cd to green onion, providing a theoretical foundation for the safe production and sustainable cultivation of green onion in Cdcontaminated soils.

Globally, escalating soil salinization poses significant abiotic stress, disproportionately impacting crops like chickpea (Cicer arientinum L.). This legume exhibits high sensitivity to salinity, which disrupts various physiological and metabolic processes, ultimately hindering growth and productivity. AMF (arbuscular mycorrhizal fungus) reduces salt's detrimental effects on plants' growth by bolstering the plant's antioxidant defense system, effectively reducing the damage caused by oxidative stress. In this study, the impact of AMF on salinity stress alleviation in chickpea was investigated in pot-grown experiments. Rhizophagus fasciculatus was used to inoculate the seeds of three different chickpea varieties (HC-3, CSG-8962, and C-235), and the physiological and biochemical changes of the AMF-inoculated and non-inoculated chickpea plants were studied. When exposed to salinity stress, the plants exhibited decreased leaf relative water content (RWC %) (21.13-31.30%), increased leaf relative stress injury, decreased chlorophyll content (45.22-58.24%), photochemical quantum yield, photosynthetic rate, transpiration rate, and stomatal conductance as compared to the control plants, but opposite results were observed in AMF colonized plants. A 9.16% to 14.79% increase in chlorophyll content was reported after AMF colonization. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) were increased by salt stress. They were further enhanced by AMF inoculation SOD activity by 20.3% to 23.3%, CAT activity by 65.7% to 78.7%, and POX activity by 32.7% to 39.3%. The findings clearly show that AMF Rhizophagus fasciculatus, via enhancing RWC, photosynthetic parameters, and antioxidant enzymes, can mitigate salinity stress in chickpeas.