Effects Of Arbuscular Mycorrhizal Fungi Research Articles

Effects of Interaction of Protein Hydrolysate and Arbuscular Mycorrhizal Fungi Effects on Citrus Growth and Expressions of Stress-Responsive Genes (Aquaporins and SOSs) under Salt Stress.

Protein hydrolysates (PHs) and arbuscular mycorrhizal fungi (AMF) are environmentally friendly biostimulants that effectively promote crop growth and alleviate the damage from abiotic stress. However, the physiological and molecular regulatory mechanisms are still unclear. This study aimed to explore the effects of PHs and AMF on growth, mineral nutrient absorption, and expression of Aquaporins and SOSs in Goutoucheng (Citrus aurantium) under salt stress. Results showed that PH application and AMF inoculation significantly promoted plant growth and enhanced mineral element absorption and sodium effluxion in citrus under salt stress. The biomass, root activity, leaves mineral nutrition contents in PHs, AMF, and combined (PHs and AMF) treatments were significantly higher than those of control. Leaves sodium content in three treatments was significantly lower than in the control. AMF and combined treatments showed dominant effects than PHs alone. Besides, PHs interacted with AMF on growth, nutrient absorption, and sodium effluxion. Importantly, AMF and PHs induced stress-responsive genes. PIP1, PIP3, SOS1, and SOS3 expression in PHs and AMF treatments was significantly higher than control. Thus, it was concluded that AMF and PHs enhanced the salt tolerance of citrus by promoting nutrient absorption and sodium effluxion via up-regulating the expression of PIPs and SOSs. The mixed application of PHs and AMF had a better effect.

Arbuscular Mycorrhizal Fungi Restored the Saline-Alkali Soil and Promoted the Growth of Peanut Roots.

Peanut (Arachis hypogaea L.) is an important oil and cash crop. An efficient utilization of saline-alkali soil resources, the development of peanut planting in saline-alkali soil, and obtaining high and stable yield have become urgent needs to ensure peanut production. Arbuscular mycorrhizal fungi (AMF) have been reported to develop the potential productivity of host plants and improve their salt resistance and tolerance. However, there is still limited research on promoting the growth and morphology of peanut roots. Therefore, in this study, seeds of salt-tolerant peanut variety "HY 25" were coated with commercial AMF inoculant before being planted in saline-alkali and normal soils to investigate the effects of AMF on peanut root growth and rhizosphere soil. The results showed that root morphological characteristics were significantly increased by the use of AMF at the podding stage in saline-alkali soil and from the flowering and pegging stage to the maturity stage in normal soil. Of note, the total root volume of peanut inoculated with AMF significantly increased by 31.57% during the podding stage in saline-alkali soil. Meanwhile, AMF significantly increased the phosphatase and invertase activities in the peanut rhizosphere of saline-alkali soil from the flowering stage to maturity stage and soil CAT activity at the maturity stage (41.16~48.82%). In normal soil, soil phosphatase and urease activities were enhanced by AMF at the flowering stage and the podding stage, respectively. AMF also increased the contents of soil organic matter, available phosphorus, and hydrolysable nitrogen, but decreased soil EC in saline-alkali soil. In addition to the significant increase in soil available phosphorus content, AMF had no significant effect on the physical and chemical properties of the soil and other soil nutrients in normal soil. AMF significantly increased pod biomass and yield in saline-alkali soil and normal soil, and improved their agronomic characteristics. In conclusion, peanut seeds coated with AMF improved the root morphological characteristics of peanuts and improved the physical and chemical properties in peanut rhizosphere, especially in saline-alkali soil. The process of rhizosphere soil nutrient transformation was also enhanced. Finally, AMF improved plant agronomic traits to increase the pod yield (16.5~21.9%). This study provides the theoretical basis and technical support for the application of AMF in peanut production in saline-alkali soil.

Arbuscular mycorrhizal fungi alter rhizosphere bacterial diversity, network stability and function of lettuce in barren soil

Arbuscular mycorrhizal fungi (AMF) play an important role in plant growth and rhizosphere microbiome composition. However, how the plant-AMF-rhizosphere microbiome continuum interacts in barren soils to efficiently promote the plant's growth is still an area of little research. Here, we present the results of a controlled environment experiment to reveal the effect of AMF on the rhizosphere bacterial community of lettuce. Compared with the control group, AMF significantly increased plant biomass, mycorrhizal colonization, and affected the rhizosphere microbial community composition. AMF inoculation changed the function of the rhizosphere bacterial community, reduced the complexity of the bacterial network, and improved its stability. In addition, SEM showed that the composition and structure of rhizosphere soil bacterial community were significantly positively correlated with soil carbon, nitrogen, and phosphorus content after adding AMF. Our findings provide new information for exploring the positive effects of plant-microbe interactions.

Integrative application of biochar and arbuscular mycorrhizal fungi for enhanced chromium resistance in Medicago sativa

Soil chromium (Cr) contamination has become an environmental problem of global concern. However, the joint effects of combined utilization of biochar and arbuscular mycorrhizal (AM) fungal inoculum, which are considered as two promising remediation strategies of soil heavy metal pollutions, on plant Cr resistance are still poorly understood. In this study, a two-factor pot experiment was conducted to investigate how biochar and AM fungus Rhizophagus irregularis regulate Medicago sativa growth, physiological trait, nutrient and Cr uptake, relevant gene expressions, soil properties, and Cr speciation, independently or synergistically. The results showed that biochar notably decreased AM colonization, while biochar and AM fungus could simultaneously increase plant dry biomass. The greatest growth promotion was observed in mycorrhizal shoots at the highest biochar level (50 g kg−1 soil) by 91 times. Both biochar application and AM fungal inoculation enhanced plant photosynthesis and P nutrition, but the promoting effects of AM fungus on them were significantly greater than that of biochar. In addition, the combined application of biochar and AM fungus dramatically reduced shoot and root Cr concentrations by up to 92 % and 78 %, respectively, compared to the non-amended treatment. Meanwhile, down-regulated expressions were observed for metal chelating-related genes. Furthermore, Cr translocation from roots to shoots was reduced by both two soil amendments. Transcriptional levels of genes involved in reactive oxygen species and proline metabolisms were also regulated by biochar application and AM fungal colonization, leading to alleviation of Cr phytotoxicity. Furthermore, AM fungal inoculation slightly elevated soil pH but decreased plant-available soil P, which was, by contrast, lifted by biochar addition. The combined application reduced soil acid-extractable Cr concentration by 40 %. This study provides new insights into comprehensively understanding of the mechanisms of biochar and AM fungi combination on improving plant Cr tolerance.

Biological Control of Three Fungal Diseases in Strawberry (Fragaria × ananassa) with Arbuscular Mycorrhizal Fungi

Similar to many other plant-based products, strawberries are susceptible to fungal diseases caused by various pathogen groups. In recent years, efforts have been made to combat these diseases using biological control methods, particularly the application of arbuscular mycorrhizal fungi (AMF). This study aimed to determine the effects of AMF (Funneliformis mosseae (Fm) and Gigaspora margarita (Gm)) on Rhizoctonia fragariae (Rf), Fusarium oxysporum (Fo), and Alternaria alternata (Aa), which are major pathogens for strawberry. The results showed that the effects of AMF on disease severity and plant growth varied depending on the pathogens involved. Rf caused the highest disease severity, followed by Fo and Aa, but all AMF treatments significantly reduced the disease severity compared to control treatments. The study also found that the specific AMF species and their combinations influenced plant growth responses under different pathogenic conditions. Different AMF treatments resulted in varying increases in plant fresh weight, dry weight, and length, depending on the pathogen. Moreover, the application of AMF led to increased levels of total phenolic content, antioxidant activity, and phosphorus content in pathogen-infected plants compared to control treatments. Fm was more efficient than Gm in increasing these biochemical parameters. The levels of root colonization by AMF were similar among different AMF treatments, but the effects on fungal spore density varied depending on the pathogen. Some AMF treatments increased fungal spore density, while others did not show significant differences. In conclusion, our research sheds light on the differential effects of AMF species on disease severity, plant growth, and biochemical parameters in strawberry plants facing diverse pathogens. These findings underscore the potential benefits of AMF in disease management, as they reduce disease severity and bolster plant growth and defense mechanisms.

Arbuscular mycorrhizal fungi improve selenium uptake by modulating root transcriptome of rice (Oryza sativa L.).

Although selenium (Se) is an essential trace element in humans, the intake of Se from food is still generally inadequate throughout the world. Inoculation with arbuscular mycorrhizal fungi (AMF) improves the uptake of Se in rice (Oryza sativa L.). However, the mechanism by which AMF improves the uptake of Se in rice at the transcriptome level is unknown. Only a few studies have evaluated the effects of uptake of other elements in rice under the combined effects of Se and AMF. In this study, Se combined with the AMF Funneliformis mosseae (Fm) increased the biomass and Se concentration of rice plants, altered the pattern of ionomics of the rice roots and shoots, and reduced the antagonistic uptake of Se with nickel, molybdenum, phosphorus, and copper compared with the treatment of Se alone, indicating that Fm can enhance the effect of fertilizers rich in Se. Furthermore, a weighted gene co-expression network analysis (WGCNA) showed that the hub genes in modules significantly associated with the genes that contained Se and were related to protein phosphorylation, protein serine/threonine kinase activity, membrane translocation, and metal ion binding, suggesting that the uptake of Se by the rice roots may be associated with these genes when Fm and Se act in concert. This study provides a reference for the further exploration of genes related to Se uptake in rice under Fm treatment.

Effectiveness of Arbuscular Mycorrhizal Fungi and NPK Fertilizer in Increasing the Production of Sweet Corn Plant

Effectiveness of Arbuscular Mycorrhizal Fungi and NPK Fertilizer in Increasing the Production of Sweet Corn Plant

Effects of arbuscular mycorrhizal fungi on plant invasion success driven by nitrogen fluctuations

Abstract Both enemies and mutualists play crucial roles in shaping plant invasion processes. Recent studies have suggested that resource fluctuations could indirectly promote plant invasion through higher trophic levels, such as enemies. However, the influence of mutualists like arbuscular mycorrhizal fungi (AMF) on plant invasion under nitrogen fluctuations remains untested. We conducted a pot mesocosm experiment using a three‐factorial experimental design to assess the individual and interactive effects of nitrogen availability, nitrogen fluctuation and AMF on invasive success of alien plants. We grew nine invasive alien species alongside five different native communities in pot mesocosms. These were then subjected to varied nitrogen availabilities (low vs. high), nitrogen fluctuations (constant vs. pulsed) and AMF presence or absence within a sterile substrate. We found that pulsed nitrogen supply increased the dominance of invasive alien species in low nitrogen availability, regardless of the presence or absence of AMF inoculation. However, in high nitrogen availability, pulsed nitrogen supply only enhanced this dominance in pots without AMF inoculation. This was tentatively evidenced by the three‐way interaction among nitrogen‐availability, nitrogen‐fluctuation and AMF‐inoculation treatments. Furthermore, the dominance promotion by nitrogen addition was greater than that by AMF inoculation. Synthesis and applications. Our findings present, for the first time, evidence that AMF may play a crucial role in mediating the promotion effects of nitrogen fluctuations on alien plant invasion. To better understand the invasion process of alien plants and evaluate their impact on native communities, future research should integrate abiotic and biotic drivers into a single framework. Furthermore, our findings underscore the importance of prioritizing habitats with higher nutrient availability and variability for protection against alien plant invasions.

An arbuscular mycorrhizal fungus differentially regulates root traits and cadmium uptake in two maize varieties

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that colonize plant roots, and they are more common in Cd-polluted habitats. However, there is limited understanding of the response of root traits and cadmium (Cd) uptake to AMF in different crop varieties. Two maize varieties, Panyu 3 and Ludan 8, with high and low Cd uptake capacities, respectively, were cultivated as host plants in a pot experiment with Cd-polluted soil (17.1 mg/kg Cd). The effects of AMF on the growth, mineral nutrient concentration, root traits, phytohormone concentrations and Cd uptake of the two maize varieties and their comprehensive response to AMF fungal inoculation were investigated. AMF improved growth, mineral nutrient levels and root morphology and increased lignin and phytohormone concentrations in roots and Cd uptake in the two maize varieties. However, the two maize varieties, Panyu 3 and Ludan 8, had different responses to AMF, and their comprehensive response indices were 753.6% and 389.4%, respectively. The root biomass, branch number, abscisic acid concentrations, lignin concentrations and Cd uptake of maize Panyu 3 increased by 151.1%, 28.6%, 139.7%, 99.5% and 84.7%, respectively. The root biomass, average diameter, auxin concentration, lignin concentration and Cd uptake of maize Ludan 8 increased by 168.7%, 31.8%, 31.4%, 41.7% and 136.7%, respectively. Moreover, Cd uptake in roots presented very significant positive correlations with the average root diameter and abscisic acid concentration. A structural equation model indicated that the root abscisic acid concentration and root surface area had positive effects on Cd uptake by the Panyu 3 maize roots; the root abscisic acid concentration and root tip number had positive effects on Cd uptake by the Ludan 8 maize roots. Thus, AMF differentially regulated Cd uptake in the two maize varieties, and the regulatory effect was closely related to root traits and phytohormone concentrations.

Efektivitas Fungi Mikoriza Arbuskula yang Diproduksi dengan Teknik Fortifikasi Nutrisi Berbeda terhadap Produktivitas Stylosanthes guianensis pada Cekaman Kekeringan

This study aimed to test the effectiveness of arbuscular mycorrhizal fungi (AMF) products against stylo plants (Stylosanthes guianensis) under drought stress conditions. The research design used a factorial complete random pattern (CRD) with 2 factors. Factor A was AMF: F0 (control), FU (superior AMF as a comparison), FIPB1 (1000ppm ABmix nutrient fortification technique), FIPB2 (2000ppm ABmix nutrient fortification technique), FIPB3 (3000ppm ABmix nutrient fortification technique). Factor B was the drought level, 100% field capacity (FC), 60% FC (medium dry level), and 40% FC (high dry level). The fertilizer for control plants (without AMF) was 100% dose, while plants with AMF were given a 50% dose, adding AMF ± 20 grams. The results showed an interaction between the drought factor and the different types of AMF. AMF was effective in symbiosis with stylo plants at all levels of drought. FIPB1 and FIPB2 could increase plant adaptation up to 60% FC. All AMF inoculations effectively increased leaf chlorophyll content at all drought levels. Biomass accumulation in FU and FIPB1 plants produced the best biomass. The research concluded that the quality of AMF produced with different nutrient fortifications were as good as the superior AMF (FU). Inoculation of AMF products (IPB1, IPB2, and IPB3) with 50% fertilization effectively increased the adaptation and production of Stylosanthes guianensis to a drought level of 60% FC compared to control (without AMF, 100% fertilization).
 Key words: Arbuscular mycorrhizal fungi, drought level, productivity, Stylosanthes guianensis

Arbuscular Mycorrhizal Fungus Funneliformis mosseae Improves Soybean Growth Even in Soils with Good Nutrition

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels.

Arbuscular mycorrhizal fungi drive soil nitrogen transformation under wheat varieties with different nitrogen utilization efficiencies

Arbuscular mycorrhizal fungi (AMF) can play important roles in plant nitrogen (N) uptake and use. However, it is still not well explored how AMF interact with host plants representing different N use types and thereby affect soil N transformation. A pot experiment was conducted to test the effects of AMF on N mineralization, nitrification, denitrification and nitrous oxide (N2O) reduction in soils under wheat varieties with high and low pre-anthesis N utilization efficiency (also called grain-specific N efficiency). Our results showed that AMF can increase N mineralization potential, with a greater effect for varieties with high N utilization efficiency. AMF also increased nitrification potential, ammonium oxidation potential, but did not nitrite oxidation potential, suggesting that AMF only act on the first nitrification step (ammonium oxidation). AMF increased NO3− but decreased NH4+ concentrations irrespective of the N use type of host plant. Moreover, AMF significantly increased denitrifying enzyme activity of the varieties with low N utilization efficiency, but decreased it for the varieties with high N utilization efficiency. N2O emission during soil incubation was in tandem with denitrification. Finally, AMF significantly increased N2O reductase activity irrespective of the N utilization efficiency of the host plant. The findings suggest that an interaction between the N utilization efficiency of wheat plants and AMF can modulate the N uptake of the host plant, and also regulate soil N transformation; a mechanism which may greatly affect the sustainability of wheat cropping systems.

Role of Arbuscular Mycorrhizal Fungi in Regulating Growth, Enhancing Productivity, and Potentially Influencing Ecosystems under Abiotic and Biotic Stresses.

Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with the roots of nearly all land-dwelling plants, increasing growth and productivity, especially during abiotic stress. AMF improves plant development by improving nutrient acquisition, such as phosphorus, water, and mineral uptake. AMF improves plant tolerance and resilience to abiotic stressors such as drought, salt, and heavy metal toxicity. These benefits come from the arbuscular mycorrhizal interface, which lets fungal and plant partners exchange nutrients, signalling molecules, and protective chemical compounds. Plants' antioxidant defence systems, osmotic adjustment, and hormone regulation are also affected by AMF infestation. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress conditions. As a result of its positive effects on soil structure, nutrient cycling, and carbon sequestration, AMF contributes to the maintenance of resilient ecosystems. The effects of AMFs on plant growth and ecological stability are species- and environment-specific. AMF's growth-regulating, productivity-enhancing role in abiotic stress alleviation under abiotic stress is reviewed. More research is needed to understand the molecular mechanisms that drive AMF-plant interactions and their responses to abiotic stresses. AMF triggers plants' morphological, physiological, and molecular responses to abiotic stress. Water and nutrient acquisition, plant development, and abiotic stress tolerance are improved by arbuscular mycorrhizal symbiosis. In plants, AMF colonization modulates antioxidant defense mechanisms, osmotic adjustment, and hormonal regulation. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress circumstances. AMF-mediated effects are also enhanced by essential oils (EOs), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA), and phosphorus (P). Understanding how AMF increases plant adaptation and reduces abiotic stress will help sustain agriculture, ecosystem management, and climate change mitigation. Arbuscular mycorrhizal fungi (AMF) have gained prominence in agriculture due to their multifaceted roles in promoting plant health and productivity. This review delves into how AMF influences plant growth and nutrient absorption, especially under challenging environmental conditions. We further explore the extent to which AMF bolsters plant resilience and growth during stress.

Effect of Arbuscular Mycorrhizal Fungi and Different Combination of Foliar Application of Nutrients on Nutrient Uptake and Yield of Aerobic Rice

Background: In Aerobic rice cultivation, crop would faces water and nutrient deficiency; it would be a difficult for roots to reach in those situation. During that stress situation VAM fungi helps to observe water along with essential nutrients results out of efficiently increases the nutrient uptake. Methods: The field experiment was conducted during 2022 at wetland farms, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore. The experiment consisted of thirteen treatments, which includes different recommended doses of VAM 50, 62.5 and 75 kg ha-1 together with different combinations of foliar application of 0.5% of urea, 0.5% of ZnSO4 and 1% of FeSO4. Conclusion: The experiment results concluded that the combined application of 150 % of recommended dose of VAM and foliar application of 0.5% urea + 0.5% of ZnSO4 + 1% of FeSO4 at 25 and 45 DAS, significantly increased the nutrient uptake, by improving the morphology of shoot and root biomass under upland condition.

Resilience of root and soil bacteria to drought stress depends on host plant's colonization affinity towards arbuscular mycorrhiza fungi

Water deficit is one of the most important climate events that has strong effect on agricultural ecosystem functionality comprising soil microbial communities and their functions. Arbuscular mycorrhizal fungi (AMF) are widely known for their roles in combating drought, including facilitation of drought-tolerant bacteria. However, differences in cultivar/variety affinity for mycorrhization have never been considered as influencing factors. In the present study, we evaluated the influence of mycorrhizal affinity of two durum wheat (T. turgidum subsp. Durum (Desf.)) varieties, Iride and Ramirez (high and low, respectively) on root and soil bacteriomes under well-watered and drought conditions. We used the 16S metagenomics approach (amplicon sequencing) to assess the bacterial communities of root and soil samples. The suppression effect of drought was evident across a wide range of bacterial taxa, including drought-tolerant taxa, especially in the non-inoculated plants. Nevertheless, the protective effect of AMF was also shown, especially in the Iride variety (high AMF colonization affinity) in both compartments (root and soil), as the relative abundance of drought-depleted taxa, such as Planctomycetes, Bacteroidetes and Verrucomicrobia, was either similar under well-watered and water deficit conditions or increased under water deficit conditions. Moreover, drought reduced the network complexity of root and soil bacteria, especially in Ramirez variety which has a lower AMF colonization affinity. Together, our results suggest that not only AMF colonization, but also host plant colonization affinity is one of the regulating factors in alleviating drought-induced changes in wheat plants by altering plant-fungal-bacterial interactions.

Evolutionary characteristics of arbuscular mycorrhizal fungi inEucalyptussoil and driving changes in biologically‐based phosphorus acrossEucalyptusplantations

AbstractArbuscular mycorrhizal fungi (AMF) symbiosis plays essential roles in shaping rhizosphere soil available phosphorus (P) and organic P mobilization. However, current methods for assessing soil P often do not fully consider the potential role of arbuscular mycorrhizal fungi (AMF) in supplying biologically‐based phosphorus (BBP) toEucalyptus. This study aims to investigate the effects of AMF on the soil BBP ofEucalyptusplantations and which species prefer to translocate them in phosphorus‐deficient soils. Rhizosphere soil samples ofEucalyptusplantations (in south China) exhibiting different ages (varying between 1 to 12 years) were selected to investigate the evolution of AMF and BBP in soils, as well as their interaction mechanism. The impacts of eight AMF families on BBP were investigated in rhizosphere soil. All BBP contents are significantly positively correlated with Olsen P in the rhizosphere soil ofEucalyptusplantations (p < 0.01). The BBP in soil was notably influenced by AMF diversity, while AMF richness showed little effect on BBP. The abundance of Glomeraceae taxa showed a positive correlation with BBP and a negative correlation with Paraglomeraceae. In contrast, the relative abundance of Glomeraceae was higher in older plantations (including Archaeosporaceae, Claroideoglomeraceae). From the above results, we concluded that different species of the AMF modulated their mycorrhizal traits by improving BBP uptake in the rhizosphere soil. AMF groups (such as Glomeraceae, Archaeosporaceae, Claroideoglomeraceae) should be introduced or amplified at the beginning of planting to promote the uptake and utilization of bioavailable P inEucalyptusplantations. This study will deepen our understanding of AMF for effective BBP utilization inEucalyptusplantations.

Sugar metabolism and 14-3-3 protein genes expression induced by arbuscular mycorrhizal fungi and phosphorus addition to response drought stress in Populus cathayana

Sugar, as a nutrient exchange substance between arbuscular mycorrhizal (AM) fungi and host plants, plays an important role in the abiotic stress response of mycorrhizal plants. This experiment aimed to study the effects of AM fungi and phosphorus (P) addition on the sugar metabolism and 14-3-3 gene expression of Populus cathayana under drought stress. The results showed that drought affects the process of sugar metabolism by increasing the activities of amylase and invertase, resulting in the decrease of starch content in leaves and roots and the accumulation of soluble sugars (including reducing sugar and sucrose) in roots. Under drought stress, the activity or content of sucrose synthetase, sucrose phosphate synthase, acid invertase, alkaline invertase, reducing sugar, soluble sugar, sucrose, and starch in the root showed the best mycorrhizal effect at the 100 mg P level. The expression levels of the 14-3-3 genes (PcGRF10 and PcGRF11) were significantly increased by mycorrhizal induction under drought stress. These levels were positively correlated with SS, SPS, sucrose, and starch phosphorylase in leaves, as well as with almost all sugar metabolism indicators in roots. However, they were negatively correlated with starch content in both leaves and roots. Sugar metabolism and 14-3-3 protein gene expression were induced by AM fungi and P addition in response to drought stress. The 14-3-3 genes induced by AM fungi may be involved in participating in osmotic regulation during drought stress. This study provides a new idea for the mechanism of sugar metabolism of mycorrhizal plants in arid regions.

Adaptive response of flavonoids in Robinia pseudoacacia L. affected by the contamination of cadmium and elevated CO2 to arbuscular mycorrhizal symbiosis

As a key component in non-enzyme resistance system, flavonoids play a crucial role in the plant growth and defenses, which are significantly affected by biotic and abiotic factors such as fungi, bacteria, viruses, heavy metals, and atmospheric CO2. Arbuscular mycorrhizal fungi (AMF) play an important role in enhancing plant tolerance to adverse environments, which can significantly affect the synthesis of flavonoids by forming mycorrhizal symbionts with plant roots. However, few studies explored the combined effects of AMF, elevated CO2, and heavy metals on flavonoids in plants. Here, we investigated the adaptive response of flavonoids accumulation in Robinia pseudoacacia L. seedlings affected by the contamination of cadmium (Cd) and elevated CO2 to arbuscular mycorrhizal symbiosis. The results showed that G. mosseae decreased (p < 0.05) Cd content in leaves by 62.2% under elevated CO2. Moreover, G. mosseae colonization led to significant decreases in robinin, quercetin, kaempferol and acacetin by 17.4%, 11.1%, 15.5% and 23.1% under elevated CO2 + Cd, respectively. Additionally, G. mosseae down-regulated (p < 0.05) expression levels of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes under elevated CO2 + Cd, and CHS and uridine diphosphate flavonoid glucosyltransferase (UFGT) activities decreased (p < 0.05). Quercetin, kaempferol and acacetin showed positive (p < 0.05) correlation with PAL and CHS genes expression and PAL, CHS, and UFGT activities. Cadmium, C/N ratio, carotenoids, leaf biomass, total chlorophyll, P, and starch in leaves and G. mosseae colonization rate in roots influenced (p < 0.05) flavonoids content. Overall, G. mosseae reduced flavonoids synthesis by down-regulating gene expression levels and activities of key enzymes under elevated CO2 + Cd. The results improved our understanding of the regulation of AMF on non-enzymatic resistance of plants grown in heavy metal-contaminated soils under increasing atmospheric CO2 scenarios.

Effectiveness of arbuscular mycorrhizal fungi in increasing growth and yield of maize overlaid on oil palm aged 4 years

Effectiveness of arbuscular mycorrhizal fungi in increasing growth and yield of maize overlaid on oil palm aged 4 years

Arbuscular Mycorrhizal Fungi Enhance Drought Stress Tolerance by Regulating Osmotic Balance, the Antioxidant System, and the Expression of Drought-Responsive Genes in Vitis vinifera L.

Background and Aims. Drought harms the growth and productivity of grapevines; it thus poses a major threat to the development of viticulture in the background of ongoing climate change. Arbuscular mycorrhizal fungi (AMF) can be used to enhance the resistance/tolerance of plants to environmental stress. The effects of AMF on the osmotic regulation, antioxidant substances, and expression of drought-responsive genes in the grapevine Vitis vinifera L. cv. Ecolly were studied. Methods and Results. The experiment was conducted in a greenhouse in a completely randomized block design with four treatments: AMF colonization, well-watered; non-AMF colonization, well-watered; AMF colonization with drought stress; and non-AMF colonization with drought stress. The concentration of sucrose and proline in the leaves was higher in mycorrhizal grapevine than in nonmycorrhizal grapevine under drought stress. The concentration of malonaldehyde, hydrogen peroxide, superoxide anion, and glutathione and the activity of superoxide dismutase and peroxidase activity in leaves were higher in mycorrhizal grapevine than in nonmycorrhizal grapevine under drought conditions. AMF inoculation affected the expression of drought-responsive genes. Mycorrhization upregulated the expression of VvNCED, VvP5CS, VvSIP, VvPIP1;2, and VvTIP2;1 genes under drought stress. Conclusions. AMF could reduce the harm caused by drought stress by regulating osmosis, antioxidant activities, and the expression of key drought-responsive genes and aquaporin genes. Significance of the Study. This work provides insights into the physiological and biochemical activities influenced by AMF on grapevine under drought stress.