Effects Of Arbuscular Mycorrhizal Fungi Research Articles

Interactions between Root Hair Development and Arbuscular Mycorrhizal Fungal Colonization in Trifoliate Orange Seedlings in Response to P Levels

Both arbuscular mycorrhizal (AM) fungi and root hairs are crucial in facilitating plant uptake of phosphorus (P), while it is unclear whether and how they respond to varying P supplies. In order to explore how AM fungal colonization and root hair development are affected by substrate P supply, trifoliate orange (Poncirus trifoliata) seedlings were inoculated with AM fungus Rhizophagus intraradices and grown under low, moderate, and high P conditions; then, root hair morphological features and AM fungal colonization were measured. Following 120 days of AM fungal inoculation, root hair density, root hair length, AM fungal colonization rate, arbuscule colonization rate, and AM fungal colonization frequency all increased significantly under P-deficient conditions but decreased under high P conditions. Moreover, the colonization of AM fungi had a major impact on root hair formation by altering the expression of related genes and the growth of epidermal cells. The effect of AM fungi was dependent on P supply levels, as evidenced by the fact that root hair density and length increased at high P levels but decreased at low P levels. As a result, root hairs may serve as a preferential site for AM fungal colonization, and their morphology could influence the early stage of AM symbiosis establishment.

Ecophysiology and Seedlings Nutrient Contents of Forest Species <i>Ricinodendron heudelotii </i>(Mull. Arg.) and <i>Cola acuminata </i>(P. Beauv.) Influenced by Biofertilizer and Salinity

<i>Ricinodendron heudelotii</i> and <i>Cola acuminata, </i>are important plants species whose exploitation became abusive over the years due to the high utilization of their fruits as Non-Timber Forest Products (NTFP). They face to multiple challenges: a recalcitrance of seeds and salinity that limits regeneration. Therefore, regeneration seems an appropriate corridor for domestication with the optimization of plant mycorrhizal symbiosis otherwise called arbuscular mycorrhizal fungi (AMF). But alongside this domestication can be added constraints due to salinity of the soils in coastal region. This justify the aim of this work which was to study dynamics and evaluate the effect of salinity and mycorrhizal biofertilizers on the <i>Ricinodendron heudelotii</i> and <i>Cola acuminata </i>seedlings. To undergo this purpose, data were collected in two villages (Kendje and Njombeng) in Mungo division, and assay were conducted in greenhouse at the Faculty of Science, University of Douala-Cameroon. In the field, the identification of species was assessed over an area of 1600 m² as well as the circumference of the trees, the individual number of <i>Ricinodendron heudelotii</i> and <i>Cola acuminata</i> among other species in order to assess their maturity and rarity in the forest. The second part was carried out in the greenhouse for the purpose of germination, obtaining seedlings and evaluating the effects of arbuscular mycorrhizal fungi (<i>Gisgaspora margarita</i>) as biofertilizers on the seedlings in saline conditions (0, 50, 100 and 200 mM of NaCl). Some parameters were determined on seedlings (plant growth, dry weight, distribution of ions in plant organs, chlorophyll and carotenoid content) over a period of twenty-six weeks. Globally <i>Cola acuminata </i>is more present in the forest (5.88%) than <i>Ricinodendron heudelotii</i> (1.47%) with average circumference of 105cm for both species. AMF-biofertilizer alleviates the deleterious effect of salt stress on plants growth parameters depending of concentration. Moreover, for those species, the distribution of Na<sup>+</sup> is more accumulated in the root’s plants unlike K<sup>+</sup> and P which are more concentrated in the leaves.

Arbuscular mycorrhizal fungi reduce soil N2O emissions by altering root traits and soil denitrifier community composition

Arbuscular mycorrhizal fungi (AMF) increase the ability of plants to obtain nitrogen (N) from the soil, and thus can affect emissions of nitrous oxide (N2O), a long-lived potent greenhouse gas. However, the mechanisms underlying the effects of AMF on N2O emissions are still poorly understood, particularly in agroecosystems with different forms of N fertilizer inputs. Utilizing a mesocosm experiment in field, we examined the effects of AMF on N2O emissions via their influence on maize root traits and denitrifying microorganisms under ammonia and nitrate fertilizer input using 15N isotope tracer. Here we show that the presence of AMF alone or both maize roots and AMF increased maize biomass and their 15N uptake, root length, root surface area, and root volume, but led to a reduction in N2O emissions under both N input forms. Random forest model showed that root length and surface area were the most important predictors of N2O emissions. Additionally, the presence of AMF reduced the (nirK + nirS)/nosZ ratio by increasing the relative abundance of nirS-Bradyrhizobium and Rubrivivax with ammonia input, but reducing nosZ-Azospirillum, Cupriavidus and Rhodopseudomonas under both fertilizer input. Further, N2O emissions were significantly and positively correlated with the nosZ-type Azospirillum, Cupriavidus and Rhodopseudomonas, but negatively correlated with the nirS-type Bradyrhizobium and Rubrivivax. These results indicate that AMF reduce N2O emissions by increasing root length to explore N nutrients and altering the community composition of denitrifiers, suggesting that effective management of N fertilizer forms interacting with the rhizosphere microbiome may help mitigate N2O emissions under future N input scenarios.

Arbuscular mycorrhizal symbiosis modulates nitrogen uptake and assimilation to enhance drought tolerance of Populus cathayana

This study aims to investigate effects of arbuscular mycorrhizal fungi (AMF) inoculation on nitrogen (N) uptake and assimilation in Populus cathayana under drought stress (DS). Herein, we measured photosynthetic performance, antioxidant enzyme system, N level and N assimilation enzymes, proteins content and distribution, transcripts of genes associated with N uptake or transport in P. cathayana with AMF (AM) or without AMF (NM) under soil water limitation and adequate irrigation. Compared with NM-DS P. cathayana, the growth, gas exchange properties, antioxidant enzyme activities, total N content and the proportion of water-soluble and membrane-bound proteins in AM-DS P. cathayana were increased. Meanwhile, nitrate reductase (NR) activity, NO3− and NO2− concentrations in AM-DS P. cathayana were reduced, while NH4+ concentration, glutamine synthetase (GS) and glutamate synthetase (GOGAT) activities were elevated, indicating that AM symbiosis reduces NO3− assimilation while promoting NH4+ assimilation. Furthermore, the transcriptional levels of NH4+ transporter genes (PcAMT1-4 and PcAMT2-1) and NO3− transporter genes (PcNRT2-1 and PcNRT3-1) in AM-DS P. cathayana roots were significantly down-regulated, as well as NH4+ transporter genes (PcAMT1-6 and PcAMT4-3) in leaves. In AM P. cathayana roots, DS significantly up-regulated the transcriptional levels of RiCPSI and RiURE, the key N transport regulatory genes in AMF compared with adequate irrigation. These results indicated that AM N transport pathway play an essential role on N uptake and utilization in AM P. cathayana to cope with DS. Therefore, this research offers a novel perspective on how AM symbiosis enhances plant resilience to drought at aspect of N acquisition and assimilation.

Effect of Arbuscular Mycorrhizal Fungi (AMF) on photosynthetic characteristics of cotton seedlings under saline-alkali stress

The study aimed to find the best Arbuscular Mycorrhizal Fungi (AMF) strain for cotton growth in Xinjiang's salinity and alkali conditions. Cotton (Xinluzao 45) was treated with Funneliformis mosseae (GM), Rhizophagus irregularis (GI), and Claroideoglomus etunicatum (GE) as treatments, while untreated cotton served as the control (CK). Salinity stress was applied post-3-leaf stage in cotton. The study analyzed cotton's reactions to diverse saline-alkali stresses, focusing on nutrient processes and metabolism. By analyzing the growth and photosynthetic characteristics of plants inoculated with Funneliformis mosseae to evaluate its salt tolerance. Saline-alkali stress reduced chlorophyll and hindered photosynthesis, hampering cotton growth. However, AMF inoculation mitigated these effects, enhancing photosynthetic rates, CO2 concentration, transpiration, energy use efficiency, and overall cotton growth under similar stress levels. GM and GE treatments yielded similar positive effects. AMF inoculation enhanced cotton plant height and biomass. In GM treatment, cotton exhibited notably higher root length than other treatments, showing superior growth under various conditions. In summary, GM-treated cotton had the highest infection rate, followed by GE-treated cotton, with GI-treated cotton having the lowest rate (GM averaging 0.95). Cotton inoculated with Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus etunicatum juvenile showed enhanced chlorophyll and photosynthetic levels, reducing salinity effects. Funneliformis mosseae had the most significant positive impact.

Arbuscular Mycorrhizal Fungi-Mediated Modulation of Physiological, Biochemical, and Secondary Metabolite Responses in Hemp (Cannabis sativa L.) under Salt and Drought Stress.

The increasing impact of global climate change has resulted in adversity stresses, like salt and drought, gradually becoming the main factors that limit crop growth. Hemp, which contains numerous medicinal active components and multiple bioactive functions, is widely used in the agricultural, industrial, and medical fields, hence promoting the rapid development of related industries. Arbuscular mycorrhizal fungi (AMF) can establish a symbiotic relationship with 80% of vascular plants. This symbiosis promotes host plant growth, regulates plant physiology and biochemistry, facilitates secondary metabolite synthesis, and enhances resistance to abiotic stresses. However, the effects of salt stress, drought stress, and AMF interaction in hemp are not well understood. In this study, to investigate this, we performed a study where we cultured hemp that was either inoculated or uninoculated with Funneliformis mosseae and determined changes in effective colonization rate, growth, soluble substances, photosynthesis, fluorescence, ions, and secondary metabolites by cultivating hemp under different concentrations of NaCl (0 mM, 100 mM, and 200 mM) and different soil moisture content (45%, 25%, and 15%). The results showed that salt, drought stress, or salt-drought interaction stress all inhibited colonization rate after stress, plant growth, mainly due to ion toxicity and oxidative damage. Inoculation with F. mosseae effectively alleviated plant growth inhibition under 100 mM NaCl salt stress, drought stress, and salt-drought interaction stress conditions. It also improved osmoregulation, photosynthetic properties, fluorescence properties, and ion homeostasis, and promoted the accumulation of secondary metabolites. However, under 200 mM NaCl salt stress conditions, inoculation with F. mosseae negatively affected plant physiology, biochemistry, and secondary metabolite synthesis, although it did alleviate growth inhibition. The results demonstrate that there are different effects of salt-drought interaction stress versus single stress (salt or drought stress) on plant growth physiology. In addition, we provide new insights about the positive effects of AMF on host plants under such stress conditions and the effects of AMF on plants under high salt stress.

Effects of arbuscular mycorrhizal fungi on the reduction of arsenic accumulation in plants: a meta-analysis.

Arsenic (As) accumulation in plants is a global concern. Although the application of arbuscular mycorrhizal fungi (AMF) has been suggested as a potential solution to decrease As concentration in plants, there is currently a gap in a comprehensive, quantitative assessment of the abiotic and biotic factors influencing As accumulation. A meta-analysis was performed to quantitatively investigate the findings of 76 publications on the impacts of AMF, plant properties, and soil on As accumulation in plants. Results showed a significant dose-dependent As reduction with higher mycorrhizal infection rates, leading to a 19.3% decrease in As concentration. AMF reduced As(V) by 19.4% but increased dimethylarsenic acid (DMA) by 50.8%. AMF significantly decreased grain As concentration by 34.1%. AMF also improved plant P concentration and dry biomass by 33.0% and 62.0%, respectively. The most significant reducing effects of As on AMF properties were seen in single inoculation and experiments with intermediate durations. Additionally, the benefits of AMF were significantly enhanced when soil texture, soil organic carbon (SOC), pH level, Olsen-P, and DTPA-As were sandy soil, 0.8%-1.5%, ≥7.5, ≥9.1 mg/kg, and 30-60 mg/kg, respectively. AMF increased easily extractable glomalin-related soil protein (EE-GRSP) and total glomalin-related soil protein (T-GRSP) by 23.0% and 28.0%, respectively. Overall, the investigated factors had significant implications in developing AMF-based methods for alleviating the negative effects of As stress on plants.

Effect of Arbuscular Mycorrhizal Fungi and Rock Phosphate on Growth, Physiology, and Biochemistry of Carob under Water Stress and after Rehydration in Vermicompost-Amended Soil.

In the Mediterranean region, reforestation programs record failures following successive drought periods. The use of different plant-growth-promoting amendments and the understanding of drought-induced physiological and biochemical responses of carob will contribute to the reforestation program's success. In this study, the effects of arbuscular-mycorrhizal-fungi (AMF), vermicompost (VC), and rock phosphate (RP) on carob seedlings under drought stress (DS) and recovery (REC) conditions were evaluated. A greenhouse experiment was conducted with carob seedlings grown in the presence of AMF, VC, and RP, applied alone or in combination under well-watered (WW), DS (by stopping irrigation for 12 days), and recovery (REC) conditions. The obtained results indicated that the triple combination (AMF + VC + RP) presented the highest improvement in water potential, photosynthetic pigment content, stomatal conductance, and chlorophyll fluorescence compared to the controls under DS and after REC. In addition, this combination resulted in improved tolerance of carob seedlings to DS and a high potential for rapid recovery after rehydration due to a high accumulation of sugars, proteins, and antioxidant enzymes. In summary, the results underline the importance of inoculating carob with AMF in combination with (in)-organic amendments in improving its tolerance to DS and its recovery performances.

Effect of arbuscular mycorrhizal symbiosis on growth and biochemical characteristics of Chinese fir (Cunninghamia lanceolata) seedlings under low phosphorus environment.

The continuous establishment of Chinese fir (Cunninghamia lanceolata) plantations across multiple generations has led to the limited impact of soil phosphorus (P) on tree growth. This challenge poses a significant obstacle in maintaining the sustainable management of Chinese fir. To investigate the effects of Arbuscular mycorrhizal fungi (AMF) on the growth and physiological characteristics of Chinese fir under different P supply treatments. We conducted an indoor pot simulation experiment in the greenhouse of the Forestry College of Fujian Agriculture and Forestry University with one-and-half-year-old seedlings of Chinese fir from March 2019 to June 2019, with the two P level treatment groups included a normal P supply treatment (1.0 mmolL-1 KH2PO4, P1) and a no P supply treatment (0 mmolL-1 KH2PO4, P0). P0 and P1 were inoculated with Funneliformis mosseae (F.m) or Rhizophagus intraradices (R.i) or not inoculated with AMF treatment. The AMF colonization rate in the root system, seedling height (SH), root collar diameter (RCD) growth, chlorophyll (Chl) photosynthetic characteristics, enzyme activities, and endogenous hormone contents of Chinese fir were estimated. The results showed that the colonization rate of F.m in the roots of Chinese fir seedlings was the highest at P0, up to 85.14%, which was 1.66 times that of P1. Under P0 and P1 treatment, root inoculation with either F.m or R.i promoted SH growth, the SH of R.i treatment was 1.38 times and 1.05 times that of F.m treatment, respectively. In the P1 treatment, root inoculation with either F.m or R.i inhibited RCD growth. R.i inhibited RCD growth more aggressively than F.m. In the P0 treatment, root inoculation with F.m and R.i reduced the inhibitory effect of phosphorus deficiency on RCD. At this time, there was no significant difference in RCD between F.m, R.i and CK treatments (p < 0.05). AMF inoculation increased Fm, Fv, Fv/Fm, and Fv/Fo during the chlorophyll fluorescence response in the tested Chinese fir seedlings. Under the two phosphorus supply levels, the trend of Fv and Fm of Chinese fir seedlings in different treatment groups was F.m > R.i > CK. Under P0 treatment, The values of Fv were 235.86, 221.86 and 147.71, respectively. The values of Fm were 287.57, 275.71 and 201.57, respectively. It increased the antioxidant enzyme activity and reduced the leaf's malondialdehyde (MDA) content to a certain extent. It is concluded that AMF can enhance the photosynthetic capacity of the host, regulate the distribution of endogenous hormones in plants, and promote plant growth by increasing the activity of antioxidant enzymes. When the P supply is insufficient, AMF is more helpful to plants, and R.i is more effective than F.m in alleviating P starvation stress in Chinese fir.

Effects of root-colonizing fungi on pioneer Pinus thunbergii seedlings in primary successional volcanic mudflow on Kuchinoerabu Island, Japan.

Root-colonizing fungi, such as mycorrhizal fungi and dark septate endophyte fungi, are often found on pioneer plant species during early primary succession. However, little is known about which fungal species are responsible for the establishment of pioneer plants when these symbionts colonize simultaneously. We investigated the root-colonizing fungal communities of Pinus thunbergii that established prior to lichens, bryophytes, and short-lived herbaceous plants in a primary successional volcanic mudflow site on Kuchinoerabu Island, Japan. We collected a total of 54 current-year and 1- to 2-year-old seedlings. The colonization of root fungi was evaluated by direct observation of key structures (e.g., mantle, arbuscule, microsclerotia, and hyphae) and molecular analysis. Of the 34 current-year seedlings collected, only 12 individuals were colonized by ectomycorrhizal (ECM) fungi. By contrast, all 1- to 2-year-old seedlings were colonized by ECM fungi. Seedlings colonized by pine-specific ECM fungi, specifically Rhizopogon roseolus and Suillus granulatus, showed higher nitrogen and phosphorus contents in their needles compared to non-ECM seedlings. Arbuscular mycorrhizal fungi and dark septate endophyte fungi were found in only two and three individuals, respectively. The high density of mycophagous deer on Kuchinoerabu-jima may contribute to the favored dispersal of ECM fungi over other root-colonizing fungi. In conclusion, the seedling establishment of P. thunbergii at the volcanic mudflow may be largely supported by ECM fungi, with negligible effects of arbuscular mycorrhizal fungi and dark septate endophytes.

Improving vanadium removal from contaminated river water in constructed wetlands: The role of arbuscular mycorrhizal fungi

Industrial activities pose a significant ecological risk to water resources as they pollute surrounding waters with vanadium (V). Although the contribution of plants and substrates to V removal in constructed wetlands (CWs) has been reported, the role of arbuscular mycorrhizal fungi (AMF) is unclear. The aim of the present study was to investigate the role of AMF in V removal in CWs and to elucidate the underlying mechanisms. Reed plants (Phragmites australis) were inoculated with an AMF strain (Rhizophagus irregularis) in CW columns, creating AMF-inoculated (+AMF) and non-inoculated (-AMF) treatments. Three levels of influent V concentrations (low: 0.50 mg L−1, medium: 1.14 mg L−1 and high: 1.52 mg L−1) were examined. The + AMF treatment showed higher V removal (60%–98%) than the control (40%–82%) in all three conditions, although the difference was not significant in some cases. The mean mycorrhizal effects were 75%, 19%, and 28% for low, moderate, and high influent V concentrations, respectively. The +AMF treatment showed a higher GRSP-bonded V concentration (5.5 mg g−1) than the -AMF treatment (4.0 mg g−1). Furthermore, +AMF treatment showed larger plants with higher V concentrations in their tissues, accompanied by increased biological concentration factors and biological accumulation factors. Given the remarkable positive effect of AMF on V removal, our study suggests that treating AMF in CWs is a worthwhile approach.

Improvement of Panax notoginseng saponin accumulation triggered by methyl jasmonate under arbuscular mycorrhizal fungi.

Panax notoginseng is a highly valued perennial medicinal herb plant in Yunnan Province, China, and the taproots are the main medicinal parts that are rich in active substances of P. notoginseng saponins. The main purpose of this study is to uncover the physiological and molecular mechanism of Panax notoginseng saponin accumulation triggered by methyl jasmonate (MeJA) under arbuscular mycorrhizal fungi (AMF) by determining physiological indices, high-throughput sequencing and correlation analysis. Physiological results showed that the biomass and saponin contents of P. notoginseng, the concentrations of jasmonic acids (JAs) and the key enzyme activities involved in notoginsenoside biosynthesis significantly increased under AMF or MeJA, but the interactive treatment of AMF and MeJA weakened the effect of AMF, suggesting that a high concentration of endogenous JA have inhibitory effect. Transcriptome sequencing results indicated that differential expressed genes (DEGs) involved in notoginsenoside and JA biosynthesis were significantly enriched in response to AMF induction, e.g., upregulated genes of diphosphocytidyl-2-C-methyl-d-erythritol kinases (ISPEs), cytochrome P450 monooxygenases (CYP450s)_and glycosyltransferases (GTs), while treatments AMF-MeJA and salicylhydroxamic acid (SHAM) decreased the abundance of these DEGs. Interestingly, a high correlation presented between any two of saponin contents, key enzyme activities and expression levels of DEGs. Taken together, the inoculation of AMF can improve the growth and saponin accumulation of P. notoginseng by strengthening the activities of key enzymes and the expression levels of encoding genes, in which the JA regulatory pathway is a key link. This study provides references for implementing ecological planting of P. notoginseng, improving saponin accumulation and illustrating the biosynthesis mechanism.

Signals and Machinery for Mycorrhizae and Cereal and Oilseed Interactions towards Improved Tolerance to Environmental Stresses.

In the quest for sustainable agricultural practices, there arises an urgent need for alternative solutions to mineral fertilizers and pesticides, aiming to diminish the environmental footprint of farming. Arbuscular mycorrhizal fungi (AMF) emerge as a promising avenue, bestowing plants with heightened nutrient absorption capabilities while alleviating plant stress. Cereal and oilseed crops benefit from this association in a number of ways, including improved growth fitness, nutrient uptake, and tolerance to environmental stresses. Understanding the molecular mechanisms shaping the impact of AMF on these crops offers encouraging prospects for a more efficient use of these beneficial microorganisms to mitigate climate change-related stressors on plant functioning and productivity. An increased number of studies highlighted the boosting effect of AMF on grain and oil crops' tolerance to (a)biotic stresses while limited ones investigated the molecular aspects orchestrating the different involved mechanisms. This review gives an extensive overview of the different strategies initiated by mycorrhizal cereal and oilseed plants to manage the deleterious effects of environmental stress. We also discuss the molecular drivers and mechanistic concepts to unveil the molecular machinery triggered by AMF to alleviate the tolerance of these crops to stressors.

Effects of Biochar and Arbuscular Mycorrhizal Fungi on Soil Health in Chinese Kale (Brassica oleracea var. alboglabra L.) Cultivation

Biochar and arbuscular mycorrhizal fungi (AMF), a promising environmentally friendly soil enhancer and biostimulant, play a crucial role in sustainable agriculture by influencing soil properties and plant growth. This research investigates the chemical properties of three biochar types [bamboo (BB-char), corn cob (CC-char), and coffee grounds (CG-char)] derived from different biomass sources and their impact on soil quality and Chinese kale growth. The results reveal significant differences in chemical properties among different types of biochar. Particularly, CG-char showed the greatest pH value and phosphorus content, with an average of 10.05 and 0.44%, respectively. On the other hand, CC-char had the highest potassium content, with an average of 2.16%. Incorporating biochar into degraded soil enhances soil structure, promoting porosity and improved texture, as evidenced by scanning electron microscope images revealing distinct porous structures. Soil chemistry analyses in treatment T2–T14 after a 42-day cultivation demonstrate the impact of biochar on pH, electrical conductivity, organic matter, and organic carbon levels in comparison to the control treatment (T1). Furthermore, the research assesses the impact of biochar on Chinese kale growth and photosynthetic pigments. Biochar additions, especially 5% BB-char with AMF, positively influence plant growth, chlorophyll content, and photosynthetic pigment levels. Notably, lower biochar concentrations (5%) exhibit superior effects compared to higher concentrations (10%), emphasizing the importance of optimal biochar application rates. The study also delves into the total phenolic content in Chinese kale leaves, revealing that the synergistic effect of biochar and AMF enhances phenolic compound accumulation. The combination positively influences plant health, soil quality, and nutrient cycling mechanisms. Overall, the research indicates the multifaceted impact of biochar on soil and plant dynamics, emphasizing the need for tailored application strategies to optimize benefits in sustainable agriculture.

Arbuscular mycorrhizae status of host plant affects offspring’s phenotype and transcriptome expression in a low-phosphorus environment

Abstract Although the effects of arbuscular mycorrhizal fungi (AMF) on host plants have been well documented, whether the effects of AMF on parental generations affect offspring performance is not fully clear. We conducted a common garden experiment to determine whether AMF status of host plants (Medicago truncatula) affects phenotype and transcriptome expression of their offspring. Seeds from four type parental treatments (low-phosphorus (P) soil without AMF, low-P soil with AMF, high-P soil without AMF and high-P soil with AMF) were grown under low-P (LPS) and normal-P soil (OHS) conditions. The flowering pattern of LP offspring was similar to their parents, such that plants with AMF flowered earlier than those without AMF under OHS condition but were opposite under LPS condition. The transcriptome differential analysis showed that some differential transcripts (45 for parental plants growing under low-P condition and 3 for parental plants growing under high-P condition) expression patterns between offspring were comparable, and that only affected by parental AMF status regardless of the P environment that offspring was grown. Others (146 for parental plants growing under low-P condition and 2 for parental plants growing under high-P condition), however, were affected both by the parental AMF status and the offspring P environment. In addition, the number of differential transcripts between offspring whose parental plants grew under high-P condition was far less than under low-P condition. These results indicate that AMF may not only affect the current generation of host plants but also affect the offspring especially when their parents have experienced a stressful environment.

Unraveling the Effects of Arbuscular Mycorrhizal Fungi on Plant Growth, Nutrient Content, and Heavy Metal Accumulation in the Contaminated Soil: A Meta-analysis

This study evaluated the effects of arbuscular mycorrhizal fungi (AMF) on plant growth, nutrient uptake, and heavy metal accumulation on polluted land using a meta-analysis approach. Data from 33 relevant studies were selected based on inclusion criteria, specifically articles in English, observational research, and investigating the role of AMF in plant growth and productivity on polluted land. The results showed that plants inoculated with AMF experienced significant accumulation of heavy metals in roots, such as Pb (p&lt;0.01), Ni (p&lt;0.01), Cr (p&lt;0.01), Mn (p&lt;0.05), Fe (p&lt;0.05), and As (p&lt;0.05). The AMF significantly reduced the accumulation of heavy metals such as Cr, Ni, Fe, and Cu on the upper part of fodder forage (p&lt;0.01). Forage growth was also enhanced due to AMF. The AMF greatly increased the fresh weight, length, and phosphorus (P) content of fodder forage roots (p&lt;0.01). It also increased the plant's biomass, fresh weight, dry weight, height, nitrogen (N), phosphorus (P), and potassium (K) contents (p&lt;0.01). In conclusion, AMF is important in increasing plant growth, nutrient uptake and reducing heavy metal accumulation in forage on polluted land.

Synergistic effects of vermicompost and mycorrhizal inoculation on arsenic tolerance and phytostabilization in safflower (Carthamus tinctorius L.).

Arsenic (As) is a hazardous metalloid, and mycorrhizal inoculation and vermicompost amendment can influence As bioremediation. However, the studies concerning the sole and joint effects of arbuscular mycorrhizal fungi (AMF) and vermicompost on the phytoremediation efficacy are limited. In the present study at first, the impact of various levels of vermicompost (0, 2, 4, and 8% w/w) was investigated on As mobility in soil and safflower (Carthamus tinctorius L.) plants grown in soils of spiked with 0, 40, and 80 mg kg-1 As. Results revealed that with increasing dose of vermicompost, bioavailable As in soil decreased which resulted in a lower bioaccumulation factor and translocation factor (TF) and led to a significant increase of tolerance index (TI) and total chlorophyll content in plants. The highest effect on TI and total As accumulation per plant was obtained in the dosage of 8% vermicompost. Therefore, in the second experiment, the sole and joint effects of 8% vermicompost and inoculation with Rhizophagus intraradices were assessed on the tolerance and accumulation of As in safflower. The addition of vermicompost aggravated mycorrhizal colonization but did not significantly influence mycorrhizal dependency under As stress. The joint effects of AMF and vermicompost improved the dry weight of roots and shoots, increased P concentration and P:As ratio in shoots, reduced malondialdehyde content, and moderated ascorbate peroxidase activity in leaves of As-stressed plants. Interestingly, co-application of AMF and vermicompost more than their sole usage decreased As concentration in shoots and TF and more strongly increased total As accumulation per plant. These findings suggest that mycorrhizal inoculation and vermicompost have a synergistic effect on As tolerance and phytostabilization efficacy of safflower plants, and their combined application may be a new option to remediate As-contaminated soils.

Arbuscular mycorrhizal fungi drive bacterial community assembly in halophyte Suaeda salsa

Halophytes inhabit saline soils, wherein most plants cannot grow, therefore, their ecological value is outstanding. Arbuscular mycorrhizal (AM) fungi can reconstruct microbial communities to assist plants with stress tolerance. However, little information is available on the microbial community assembly of AM fungi in halophytes. A pot experiment was conducted to investigate the effects of AM fungi on rhizosphere bacterial community structure and soil physiochemical characteristics in the halophyte Suaeda salsa at 0, 100, and 400 mM NaCl. The results demonstrated that AM fungi increased soil alkaline phosphatase (ALP) activity at the three NaCl concentrations, and decreased available P, available K, and the activity of soil catalase (CAT) at 100 mM NaCl. AM fungi decreased the Shannon index of the community at 0 and 100 mM NaCl and increased Sobs index at 400 mM NaCl. Regarding the bacterial community structure, AM fungi substantially decreased the abundance of Acidobacteria phylum at 0 and 100 mM NaCl. AM fungi significantly increased the abundance of genus Ramlibacter, an oxyanion-reducing bacteria that can clean out reactive oxygen species (ROS). AM fungi recruited the genera Massilia and Arthrobacter at 0 and 100 mM NaCl, respectively. Some strains in the two genera have been ascribed to plant growth promoting bacteria (PGPB). AM fungi increased the dry weight and promoted halophyte growth at all three NaCl levels. This study supplements the understanding that AM fungi assemble rhizosphere bacterial communities in halophytes.

Effects of arbuscular mycorrhizal fungi on carbon assimilation and ecological stoichiometry of maize under combined abiotic stresses

Abstract Arbuscular mycorrhizal fungi (AMF) enhance plant tolerance to abiotic stresses like salinity and improve crop yield. However, their effects are variable, and the underlying cause of such variation remains largely unknown. This study aimed to assess how drought modified the effect of AMF on plant resistance to high calcium-saline stress. A pot experiment was performed to examine how AMF inoculation affects the growth, photosynthetic activity, nutrient uptake and carbon (C), nitrogen (N) and phosphorus (P) stoichiometric ratio (C:N:P) of maize under high calcium stress and contrasting water conditions. The results showed that high calcium stress significantly reduced mycorrhizal colonization, biomass accumulation, C assimilation rate and C:N stoichiometric ratio in plant tissues. Besides, the adverse effects of calcium stress on photosynthesis were exacerbated under drought. AMF inoculation profoundly alleviated such reductions under drought and saline stress. However, it barely affected maize performance when subjected to calcium stress under well-watered conditions. Moreover, watering changed AMF impact on nutrient allocation in plant tissues. Under well-watered conditions, AMF stimulated P accumulation in roots and plant growth, but did not induce leaf P accumulation proportional to C and N, resulting in increased leaf C:P and N:P ratios under high calcium stress. In contrast, AMF decreased N content and the N:P ratio in leaves under drought. Overall, AMF inoculation improved maize resistance to calcium-salt stress through enhanced photosynthesis and modulation of nutrient stoichiometry, particularly under water deficit conditions. These results highlighted the regulatory role of AMF in carbon assimilation and nutrient homeostasis under compound stresses, and provide significant guidance on the improvement of crop yield in saline and arid regions.

Effects of biofertilizer on the production of bell pepper (Capsicum annuum L.) in greenhouse

Biological fertilizers are useful sources of plant nutrients that enhance crop growth and quality, produce plant hormones, and contribute to sustainable crop production by maintaining soil fertility. The effect of arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPRs) applications in greenhouses on bell pepper (Capsicum annuum L. Nervin) has been studied by conducting a split plot experiment in three replications using a randomized complete block design. The biofertilizers included AMF inoculations (Rhizophagus irregularis + Funneliformis mosseae), and three different bacterial inoculations (Azotobacter chroococcum + Azospirillum lipoferum; Enterobacter cloacae + Pseudomonas putida; Bacillus subtilis + Bacillus amyloliquefaciens) and non-inoculation as a control with two levels of organic fertilizers (with and without).The organic treatment fertilizer, in combination with the inoculation of E. cloacae + P. putida or A. chroococcum + A. lipoferum, as well as AMF, significantly increased the microbial population within the rhizosphere compared to the control. In all treatments, fruit yield increased, with the highest value (15.94 kg m−2) recorded in the AMF treatment, indicating an increase of 18% over the control. All inoculations significantly increased total phenol and ascorbic acid levels in fruit when organic fertilizer was applied. The most significant N uptake was observed in A. crococcum + A. lipoform inoculation, while the most significant Fe uptake was observed in AMF. It was found that all inoculations significantly increased P, K, and Zn uptake. In conclusion, A combination of organic fertilizer and mycorrhizal or (Azotobacter chroococcum + Azospirillum lipoferum) inoculations increased the productivity and quality of bell peppers grown in greenhouses.