Search Results (251)

Agriculture remains a key contributor to Central America’s economy, despite climate change posing a significant threat to the sector. In the Trifinio region, already afflicted by arid summers, temperatures are expected to rise in the near future, potentially exacerbating the vulnerability of smallholder farmers. This study investigates the effects of two fungal symbionts, Trichoderma asperellum (TR) and the Arbuscular mycorrhiza fungi (AMF) Glomus cubense, and agronomic choices and practices such as cultivar selection, substrate type, and fertigation management on tomato (Solanum lycopersicum L.) seedling growth and quality. Results showed that nutrient solution and the adoption of forest topsoil as substrate significantly enhanced morphological, physiological, and quality parameters. Modifying the nutrient solution to allow for an increase in plant height of 170% and a dry weight of 163% and enhancing Dickson’s quality index (DQI) by 64.5%, while the use of forest topsoil resulted in plants 58.6% higher, with an increase of 101% in dry weight and of 90.1% in the DQI. Both T. asperellum and G. cubense had positive effects on specific growth parameters; for instance, TR increased leaf number (+6.95%), while AMF increased stem diameter (+3.56%) and root length (+19.1%), although they did not, overall, significantly increase the seedling’s biomass and quality. These findings underscore the importance of agronomic practices in mitigating the impacts of climate change on tomato production, offering valuable insights for farmers in semi-arid regions. Full article

Cucumber, a vital greenhouse crop, thrives in soils with a pH range of 5.5–6.5, yet the combined effects of arbuscular mycorrhizal fungi (AMF) and iron amino chelates on its growth and physiological responses across varying pH levels remain underexplored. This study used a factorial design in a completely randomized setup with three replications and was conducted at the Horticulture Department of Isfahan University of Technology. The aim of this study was to investigate the effects of AMF inoculation (Glomus mosseae) and iron amino chelates on the growth and physiological responses of cucumber plants at various pH levels. Treatments included two levels of AMF inoculation (non-inoculated as m1 and inoculated as m²), three levels of iron concentration (f1: no iron, f2: Johnson’s nutrient solution, f3: Johnson’s solution with iron amino chelate), and three pH levels (pH 5 (p1), pH 7 (p2), and pH 8 (p3)). The moisture was maintained at field capacity throughout the study. The results demonstrated that mycorrhizal inoculation at pH 7 significantly improved key traits, including chlorophyll content, photosynthesis rate, stomatal conductance, phenol content, and antioxidant activity. Mycorrhizal inoculation combined with 2 ppm of Fe amino chelate at pH 7 led to the highest improvement in shoot fresh weight of cucumber and physiological traits. However, at pH 7 without mycorrhiza, stress indicators such as ABA levels and antioxidant enzyme activities (SOD, POD, CAT, and APX) increased, highlighting the protective role of AMF under neutral pH conditions. In contrast, pH 5 was most effective for enhancing root and stem fresh weight. The lower pH may have facilitated better nutrient solubility and uptake, promoting root development and overall plant health by optimizing the availability of essential nutrients and reducing competition for resources under more acidic conditions. These findings highlight the potential of combining mycorrhizal inoculation with iron amino chelates at pH 7 not only to enhance cucumber growth and resilience in nutrient-limited environments but also to contribute to sustainable agricultural practices that address global challenges in food security and soil health. Full article

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. Full article

It is well known that individual pea (Pisum sativum L.) cultivars differ in their symbiotic responsivity. This trait is typically manifested with an increase in seed weights, due to inoculation with rhizobial bacteria and arbuscular mycorrhizal fungi. The aim of this study was to characterize alterations in the root proteome of highly responsive pea genotype k-8274 plants and low responsive genotype k-3358 ones grown in non-sterile soil, which were associated with root colonization with rhizobial bacteria and arbuscular mycorrhizal fungi (in comparison to proteome shifts caused by soil supplementation with mineral nitrogen salts). Our results clearly indicate that supplementation of the soil with mineral nitrogen-containing salts switched the root proteome of both genotypes to assimilation of the available nitrogen, whereas the processes associated with nitrogen fixation were suppressed. Surprisingly, inoculation with rhizobial bacteria had only a minor effect on the root proteomes of both genotypes. The most pronounced response was observed for the highly responsive k-8274 genotype inoculated simultaneously with rhizobial bacteria and arbuscular mycorrhizal fungi. This response involved activation of the proteins related to redox metabolism and suppression of excessive nodule formation. In turn, the low responsive genotype k-3358 demonstrated a pronounced inoculation-induced suppression of protein metabolism and enhanced diverse defense reactions in pea roots under the same soil conditions. The results of the study shed light on the molecular basis of differential symbiotic responsivity in different pea cultivars. The raw data are available in the PRIDE repository under the project accession number PXD058701 and project DOI 10.6019/PXD058701. Full article

Fruits and vegetables play a crucial role in addressing food security challenges posed by the growing global population. Citrus fruits are among the most widely cultivated crops worldwide; however, their production is steadily declining due to climate change. Among the various biotic and abiotic stresses affecting citrus production, water scarcity caused by climate change stands out as a significant issue. Interestingly, the rhizosphere of citrus plants is home to beneficial fungi known as arbuscular mycorrhizal fungi (AMF). AMF have been shown to enhance the growth and development of host plants. They also improve the plants’ tolerance to various stresses and enhance soil structure. This study aimed to evaluate the response of two different citrus rootstocks—Rangpur lime and Carrizo citrange—when subjected to three mycorrhizal treatments, namely, AMF+ (inoculated with AMF), AMF- (treated with fungicide to eliminate AMF), and a control (naturally occurring AMF), under conditions of water deficit. The results indicated that the AMF+ treatment had a significant positive effect on both rootstock genotypes compared to the AMF- treatment. Physiological attributes such as photosynthesis, stomatal conductance, transpiration, non-photochemical quenching, and both dark and light quantum yield exhibited significantly smaller declines under water deficit conditions in AMF+ plants compared to those in the AMF- and control groups. Conversely, stress indicators—such as malondialdehyde (MDA) and hydrogen peroxide (H₂O₂)—increased significantly in the AMF- treatment compared to AMF+. Additionally, the increase in antioxidative enzymes (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APx) and osmotic adjustment (proline (PRO)) was more pronounced in the AMF+ treatment in the leaves and roots of both citrus rootstocks. In conclusion, the findings suggest that the presence and application of AMF in citrus roots may enhance the plants’ ability to cope with water scarcity more effectively. Full article

Acrostichum aureum is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide. Furthermore, AMF/AM are well known for their capacity to bioaccumulate toxic elements and to alleviate biotic and abiotic stress (e.g., salinity stress) in their hosts. However, the mechanisms underlying AMF involvement in the halophytism of A. aureum and the structures where NaCl accumulates remain unknown. This study shows that A. aureum forms AM in margins of natural thermal ponds in Neotropical wetlands. All mature sporophytes were colonised by AMF, with high percentages for root length (ca. 57%), arbuscules (23), and hyphae (25) and low values for vesicles (2%). In A. aureum–AMF symbiosis, NaCl accumulated in AMF vesicles, and CaSO₄ precipitated in colonised roots. Therefore, AM can contribute to the halophytic nature of this fern, allowing it to thrive in saline and thermal environments by capturing NaCl from fern tissues, compartmentalising it inside its vesicles, and precipitating CaSO₄. Full article

Agricultural systems are particularly impacted by global climate change (CC), responsible for the introduction of multiple environmental stressors negatively affecting plant growth. Soil microbial communities are crucial in agricultural practices, influencing crop performance and soil health. Human activities and CC threaten soil microbial biodiversity, leading to soil quality degradation and decreasing plant health and productivity. Among plant-beneficial microorganisms, mycorrhizal fungi are widespread in terrestrial ecosystems, including agroecosystems, and they play a key role by enhancing plants’ fitness and resilience to both abiotic and biotic stresses. Therefore, exploring the role of mycorrhizal symbiosis in sustainable agriculture has become increasingly critical. Moreover, the application of mycorrhizal bioinoculants could reduce dependence on inorganic fertilizers, enhance crop yield, and support plants in overcoming environmental stresses. This review, after briefly introducing taxonomy, morphology and mechanisms supporting the symbiosis establishment, reports the roles of mycorrhizal fungi and their associated bacteria in improving plant nutrition and mitigating CC-induced abiotic stresses such as drought and salinity, also giving specific examples. The focus is on arbuscular mycorrhizal fungi (AMF), but ericoid mycorrhizal (ErM) fungi are also considered as promising microorganisms for a sustainable agricultural model. New emerging concepts are illustrated, such as the role of AMF hyphosphere in acting as a preferential niche to host plant growth-promoting bacteria and the potential of ErM fungi to improve plant performance on Ericaceae plants but also on non-host plants, behaving as endophytes. Finally, the potential and limitations of mycorrhizal-based bioinoculants are discussed as possible alternatives to chemical-based products. To this aim, possible ways to overcome problems and limitations to their use are discussed such as proper formulations, the systematic check of AMF propagule viability and the application of suitable agronomical practices in the field. Full article

Soil microorganisms play a significant role in the dynamic regulation of organic matter in soils. To assess the influence of agricultural practices on soil functional profiling, we examined the effect of soil disturbance and plant sequence with different levels of mycotrophy on wheat microbiomes metabolism. Soil samples were analyzed with community-level physiological profiles (CLPP) using Biolog™ Ecoplates. The results of average well color development (AWCD) showed that the degree of mycotrophy of preceding crop and soil disturbance affected the soil microbiome, although no impact on Shannon Evenness Index was observed during the experiment. The Shannon–Wiener Diversity Index showed variations among the different preceding plants, but not in wheat analysis. The pattern of the C sources metabolism also changed differentially regarding plant type and soil disturbance during the experiment, being also different within the highly mycotrophic plants (legume and grass). In the legume, an increase in the metabolism of amine/amides and phenolic acids was observed, whilst in the grass, an increase in the metabolism of phosphate-carbons (P carbon) and carbohydrates was more evident. Principal component analysis showed that a grouping in the distinct phases of the experiment correlated with the widening of the metabolism of amino acids, carboxylic acids, and carbohydrates. The results indicate that soil functional community structure reflects soil agricultural practice conditions. Previous plant types and soil disturbance impacted the soil microbiome metabolic response (AWCD) in wheat, generating different patterns of carbon metabolism related to previous plant mycotrophy. Full article

Alfalfa, a crop cultivated worldwide for use as livestock feed, exhibits great adaptability to various environmental conditions. This study evaluates the biomass production, lipid peroxidation, photosynthetic pigments and osmo-compatible response in Medicago sativa var CW660 mycorrhizae (AM) and non-mycorrhizae (NM) plants with Rhizophagus intraradices and when subjected to salinity (100 mM and 200 mM of NaCl). They were evaluated using the following morphological parameters: foliage fresh weight (FFW), foliage dry weight (FDW), root fresh weight (RFW), root dry weight (RDW), foliage length (FL) and root length (RL), chlorophylls a and b, proline and malondialdehyde (MDA) in AM and NM plants treated with different concentration of NaCl. The LFW and the LDW were higher in M plants. The RFW and the RDW increased in control AM plants, and under different saline treatments there were no differences between AM and NM in either parameter. FL increased in the control and at 100 mM of NaCl in M plants. Chlorophyll a decreased 27–30% and b decreased 1–50% in AM and NM plants at 200 mM NaCl. The proline level increased four times and promoted a defense in AM plants at 200 mM of NaCl. Lipid peroxidation decreased in AM plants by 10% at maximum salinity. M. sativa CW660 is sensitive to salinity stress, and inoculation with arbuscular mycorrhizal fungi (AMF) regulates its physiology and performance under such conditions, with osmotic protection and membrane protection. Full article

Arbuscular mycorrhizal fungi (AMF) can form symbionts with plant roots, acquire soil nitrogen, and affect nitrous oxide (N₂O) production. Biochar, as a soil additive for the management of agricultural soil, affects soil nitrogen (N) utilization and plant growth. However, how AMF regulates soil N unitization, the denitrification process, and N₂O emissions in plant–soil systems remains largely unknown, particularly under the biochar amendment. In this study, a microcosm experiment was conducted to investigate the impacts of different mycorrhizal treatments (CK: neither AMF hyphae nor plant roots; AMF: only AMF hyphae; AMF + R: AMF hyphae and plant roots) on plant growth, soil N fertilizer utilization, N₂O production and consumption, functional gene abundance, and N₂O emission at two biochar addition levels (B0: no biochar; B1: biochar addition rate of 10 g·kg⁻¹ soil) in a maize planting soil system. The results revealed that AMF alone and AMF with plant root treatments enhanced the fresh weight of maize plants by 10.15% and 19.23% and decreased soil inorganic N contents by 33.28% and 75.56%, respectively. The combination of biochar, AMF, and plant roots showed the largest increase in maize plant biomass. The AMF and AMF with root treatments all significantly decreased the nirS + nirK/nosZ ratio and N₂O emissions at two biochar levels. The presence of AMF and plant roots during biochar amendment showed the smallest nirS + nirK/nosZ ratio and N₂O emissions. The AMF combined with biochar and AMF and plant roots combined with biochar treatments increased nirS + nirK/nosZ by 24.32% and 26.90% and decreased N₂O accumulation emission by 21.12% and 38.13%, respectively. The results imply that biochar, AMF, and plant roots reduced N₂O emissions directly by reducing soil N and increasing soil N unitization efficiency and indirectly by shifting the N₂O production and consumption gene abundance in agroecosystems. These findings suggest that the addition of biochar and AMF and/or the presence of plant roots can interact to alleviate soil N₂O emissions by manipulating plant inorganic N acquisition and the soil denitrification process. Full article

Due to shallow root systems, potato is a particularly drought-sensitive crop. To counteract these limitations, the application of plant growth-promoting microorganisms (PGPMs) is discussed as a strategy to improve nutrient acquisition and biotic and abiotic stress resilience. However, initial root colonization by PGPMs, in particular, can be affected by stress factors that negatively impact root growth and activity or the survival of PGPMs in the rhizosphere. In this study, perspectives for the use of commercial silicate-based soil conditioners (SCs) supposed to improve soil water retention were investigated. The SC products were based on combinations with lignocellulose polysaccharides (Sanoplant^® = SP) or polyacrylate (Geohumus^® = GH). It was hypothesized that SC applications would support beneficial plant–inoculant interactions (arbuscular mycorrhiza, AM: Rhizophagus irregularis MUCL41833, and Pseudomonas brassicacearum 3Re2-7) on a silty loam soil–sand mixture under water-deficit conditions (6–12 weeks at 15–20% substrate water-holding capacity, WHC). Although no significant SC effects on WHC and total plant biomass were detectable, the SC-inoculant combinations increased the proportion of leaf biomass not affected by drought stress symptoms (chlorosis, necrosis) by 66% (SP) and 91% (GH). Accordingly, osmotic adjustment (proline, glycine betaine accumulation) and ROS detoxification (ascorbate peroxidase, total antioxidants) were increased. This was associated with elevated levels of phytohormones involved in stress adaptations (abscisic, jasmonic, salicylic acids, IAA) and reduced ROS (H₂O₂) accumulation in the leaf tissue. In contrast to GH, the SP treatments additionally stimulated AM root colonization. Finally, the SP-inoculant combination significantly increased tuber biomass (82%) under well-watered conditions, and a similar trend was observed under drought stress, reaching 81% of the well-watered control. The P status was sufficient for all treatments, and no treatment differences were observed for stress-protective nutrients, such as Zn, Mn, or Si. By contrast, GH treatments had negative effects on tuber biomass, associated with excess accumulation of Mn and Fe in the leaf tissue close to toxicity levels. The findings suggest that inoculation with the PGPMs in combination with SC products (SP) can promote physiological stress adaptations and AM colonization to improve potato tuber yield, independent of effects on soil water retention. However, this does not apply to SC products in general. Full article

Saline–alkali (SA) stress is an abiotic stress that exists widely in the natural environment, seriously affecting the growth and development of crops. Tiger nut (Cyperus esculentus L.), a perennial herb of Cyperus in Cyperaceae, is considered a pioneer crop for growing and improving SA land due to its excellent adaptability and SA tolerance. This study is the first to evaluate the SA tolerance of tiger nut and the alleviative effects of nanomaterials (nano-selenium and multi-walled carbon nanotubes) and Arbuscular mycorrhizas (AMs) on SA stress. The results showed that the seedling fresh weight of tiger nut was the most suitable parameter to describe the dose–response effect of plant growth with increased SA concentration. Based on the log-logistic dose–response curve, the GR₅₀ values of NaCl and NaHCO₃ (the concentrations causing a 50% reduction in seedling fresh weight) were determined to be 163 mmol L⁻¹ and 63 mmol L⁻¹, respectively. Under these stresses, the exogenous application of MWCNTs at 100 mg L⁻¹ or Nano-Se at 10 mg L⁻¹ showed that the effect of SA on tiger nut was alleviated. Field evaluation further showed that the exogenous application of MWCNTs, Nano-Se, or AMs could effectively alleviate SA stress on tiger nut. Compared to the untreated control, the application of these substances significantly improved the plant photosynthesis-related parameter, antioxidant enzyme activity, plant height (height: 66.0–69.9 cm), tuber yield (yield: 23.4–27.4 g plant⁻¹), and oil quality of tiger nut under SA stress. The results of this study indicate that the application of MWCNTs, Nano-Se, or AMs, to tiger nut can alleviate SA stress and maintain seed yield, providing the possibility of using these nanoparticles to improve the SA tolerance of tiger nut in agricultural practice. Full article

Salinity, resulting from climate change and excessive mineral fertilization, burdens farmers and negatively impacts soil and water ecosystems in the Northeastern Nile Delta. Organic and biological approaches are crucial for addressing these issues. This study examined the effects of individual and combined inoculations with cyanobacteria, yeast, and Arbuscular Mycorrhizal Fungi (AMF), with or without K-Humate and reducing Nitrogen, phosphorus and potassium (NPK) mineral fertilizers application rates to crop quality of wheat and faba bean. In preliminary laboratory experiments, the interactive effects of these microbiomes on plant antioxidant and soil enzyme production were examined under salinity stress. Results showed that co-inoculation, especially with K-Humate, yielded superior outcomes compared to individual inoculations. These findings were validated by a field trial conducted in saline-alkaline soil in the Northeastern Nile Delta region. All biological treatments 25% of recommended doses, and enhancing salinity tolerance, increasing yield, and improving enhanced rhizosphere microbial activity, including soil enzyme activity, AMF colonization, spore density, and the total numbers of bacteria, cyanobacteria, and yeast. These effects were further amplified by K-Humate and were more pronounced with combined inoculations than with individual ones, leading to improved soil fertility and significant increases in both crop quantity and quality compared to control treatments. The triple treatment, combining cyanobacteria, yeast, and mycorrhizae in the presence of K-Humate while reducing the mineral NPK rate by 75%, achieved superior increases in the productivity of wheat grains and faba bean seeds, reaching 54.72% and 128.92%, respectively, compared to the 100% NPK mineral control. This treatment also significantly improved crop quality, with notable increases in nitrogen, potassium, phosphorus, and protein percentages in wheat grains and faba bean seeds. Microbiomes-interaction increased potassium uptake over sodium, enhancing the plant’s potassium/sodium ratio and improving salt stress tolerance. This approach reduces reliance on costly mineral fertilizers, enabling bio-organic farming in marginal lands, optimizing resource utilization, and preserving natural resources. Full article

Green roofs and walls play an important role in promoting biodiversity, reducing the urban heat island effect and providing ecosystem services in urban areas. However, the conditions on green walls/roofs (low nutrient and organic matter content, drought, high temperatures) are often unfavorable for plant growth. Arbuscular mycorrhizal fungi (AMF) can improve the growth and development of plants under stress conditions as they can increase nutrient and water uptake. In a 6-month pot experiment, we investigated the effect of AMF inoculation on the growth and NPK uptake of Festuca ovina L. and Trifolium medium L., which are used for green roofs and walls. Two variants of mycorrhizal inoculation were used in the experiment: a commercial mycorrhizal inoculant AM Symbivit (Symbiom Ltd., Lanskroun, Czech Republic) and a mycorrhizal inoculant collected from calcareous grassland in the Silesia region (Poland). Funneliformis mosseae was the most abundant species in the roots of F. ovina and T. medium with IM inoculum. In the CM variant, a dominance of F. mosseae was observed in the roots of F. ovina. In contrast, Archaeosporaceae sp. node 317 dominated in the roots of T. medium. Both inoculations had a positive effect on the increase in dry weight of the shoots of T. medium, but only the commercial inoculum had a positive effect on the growth of F. ovina. Both inoculations improved the P uptake by the roots and the P and K uptake into the shoots of T. medium. In addition, both inoculations improved the K uptake by the roots of F. ovina and the N, P and K uptake into the shoots. In conclusion, both AMF communities included in the inoculations had a positive effect on plant growth and nutrient uptake, but the effect depends on the plant and the mycorrhizal fungus species. Full article

The interaction between woody plants and mycorrhizal fungi is an important biological interaction; however, the driving factors behind the diversity of mycorrhizal trees formed through the symbiosis of mycorrhizal fungi and woody plants remain unclear. In this study, we collected and compiled the woody plant data of 34 forest dynamic plots containing 3350 species from habitats around the world and divided them into AM and EcM trees. We tested the contribution of AM and EcM trees to tree diversity and its components in forest communities worldwide. Our results showed that AM trees rather than EcM trees affect the tree diversity of forest communities, and that the diversity of AM trees has a significant latitudinal gradient pattern. Climate variables, especially temperature, are strongly correlated with the diversity patterns for AM trees rather than EcM trees. Topography is the most significant factor affecting the diversity of EcM trees. Our findings highlight the importance of AM trees for the tree diversity of forest communities worldwide. Our findings have important implications for understanding the response of complex woody plant communities with different types of mycorrhizal symbiosis to climate change. Full article