Role Of Arbuscular Mycorrhizal Fungi Research Articles

The Role of Arbuscular Mycorrhiza Fungi in the Decomposition of Fresh Residue and Soil Organic Carbon: A Mini‐Review

Core Ideas Our discussion highlights the role of arbuscular mycorrhizal fungi in organic decomposition processes. Arbuscular mycorrhizal fungi can stimulate fresh residue decomposition initially and then tend to suppress the decomposition of old or decomposed soil organic carbon. We offer implication that arbuscular mycorrhizal fungi would benefit soil carbon gain in the long term even under elevated atmospheric carbon dioxide. Arbuscular mycorrhizal fungi (AMF) are widespread in terrestrial ecosystems. In addition to their contributions to plant nutrient uptake, AMF also provide many ecological functions including regulation of soil C dynamics. However, both stimulating and retarding soil organic decomposition by AMF have been observed. Here we discuss the possible reasons for such a contradiction. Arbuscular mycorrhizal fungi contribute to soil aggregation mainly through hyphal enmeshment, saprotrophic suppression, and production of glomalin‐related soil proteins, while AMF can also stimulate organic decomposition through promoting degradative enzymes, modifying root production and activity, and/or through regulating the microbial community in the mycorrhizosphere and hyphosphere. The role of AMF in C decomposition is strongly dependent on the quality and quantity of different soil C pools. Arbuscular mycorrhizal fungi can stimulate fresh residue decomposition initially through stimulating the decomposition of fresh residues (particularly those having high C/N ratio), whereas for older or decomposed soil organic C, AMF tend to suppress decomposition by promoting soil aggregation. Under elevated CO2 (eCO2), AMF show additive effects on residue decomposition, priming effects, and changes in soil aggregation. Despite organic decomposition rates differing in the short term and long term following litter experiments, our discussion highlights the role of AMF in organic C dynamics. We hypothesize that AMF would benefit soil C gain in the long term and thereby predict that disturbances that impacts negatively on AMF, such as tillage, residue burning, fertilization, and fungicide application, would lead to soil C decline particularly under eCO2.

The role of arbuscular mycorrhizal fungi on acclimatization of micropropagated plantlet Satureja khuzistanica Jam. by ameliorating of antioxidant activity and expression of PAL gene

In this study, the effect of mycorrhiza on the antioxidative system of Satureja khuzistanica plantlet has been investigated to increase its compatibility on ex vitro conditions. The relative gene expression of PAL, total flavonoid rate, activity of PAL enzyme, antioxidative enzymes and the rate of membrane lipid peroxidation in micropropagated plantlet after inoculation were measured in four steps after being transferred to ex vitro conditions. The relative expression of PAL gene (biosynthesis gene of flavonoids) increased in the leaves and roots of AM plantlets compared with non-inoculated plantlet. Increasing the relative gene expression of PAL increased the biosynthesis of the PAL enzyme and subsequently flavonoids in AM plantlets which leads to the integrity of the membrane and inhibition of oxidative damage in transition stress conditions. The enhancement of antioxidant enzymes (catalase, peroxidase) in the non-inoculated plantlet indicates that the rate of oxidative stress in the control plantlet is higher than AM plantlet. The higher amount of the rate of membrane lipid peroxidation in non-inoculated plantlet showed that the transition stress has enhanced the peroxidation of lipids, therefor, AM is able to help the plantlet to exhibit more resistant to this stress. By increasing the gene expression of the biosynthetic pathway of the flavonoids, it reduces the oxidative stress on the tissue culture plants.

Molecular dialogue between arbuscular mycorrhizal fungi and the nonhost plant Arabidopsis thaliana switches from initial detection to antagonism.

Approximately 29% of all vascular plant species are unable to establish an arbuscular mycorrhizal (AM) symbiosis. Despite this, AM fungi (Rhizophagus spp.) are enriched in the root microbiome of the nonhost Arabidopsis thaliana, and Arabidopsis roots become colonized when AM networks nurtured by host plants are available. Here, we investigated the nonhost-AM fungus interaction by analyzing transcriptional changes in Rhizophagus, Arabidopsis and the host plant Medicago truncatula while growing in the same mycorrhizal network. In early interaction stages, Rhizophagus activated the Arabidopsis strigolactone biosynthesis genes CCD7 and CCD8, suggesting that detection of AM fungi is not completely impaired. However, in colonized Arabidopsis roots, fungal nutrient transporter genes GintPT, GintAMT2, GintMST2 and GintMST4, essential for AM symbiosis, were not activated. RNA-seq transcriptome analysis pointed to activation of costly defenses in colonized Arabidopsis roots. Moreover, Rhizophagus colonization caused a 50% reduction in shoot biomass, but also led to enhanced systemic immunity against Botrytis cinerea. This suggests that early signaling between AM fungi and Arabidopsis is not completely impaired and that incompatibility appears at later interaction stages. Moreover, Rhizophagus-mediated defenses coincide with reduced Arabidopsis growth, but also with systemic disease resistance, highlighting the multifunctional role of AM fungi in host and nonhost interactions.

Investigation of Plant Interactions Across Common Mycorrhizal Networks Using Rotated Cores.

Arbuscular mycorrhizal (AM) fungi influence plant mineral nutrient uptake and growth, hence, they have the potential to influence plant interactions. The power of their influence is in extraradical mycelia that spread beyond nutrient depletion zones found near roots to ultimately interconnect individuals within a common mycorrhizal network (CMN). Most experiments, however, have investigated the role of AM fungi in plant interactions by growing plants with versus without mycorrhizal fungi, a method that fails to explicitly address the role of CMNs. Here, we propose a method that manipulates CMNs to investigate their role in plant interactions. Our method uses modified containers with conical bottoms with a nylon mesh and/or hydrophobic material covering slotted openings, 15N fertilizer, and a nutrient-poor interstitial sand. CMNs are left either intact between interacting individuals, severed by rotation of containers, or prevented from forming by a solid barrier. Our findings suggest that rotating containers is sufficient to disrupt CMNs and prevent their effects on plant interactions across CMNs. Our approach is advantageous because it mimics aspects of nature, such as seedlings tapping into already established CMNs and the use of a suite of AM fungi that may provide diverse benefits. Although our experiment is limited to investigating plants at the seedling stage, plant interactions across CMNs can be detected using our approach which therefore can be applied to investigate biological questions about the functioning of CMNs in ecosystems.

Disentangling carbon flow across microbial kingdoms in the rhizosphere of maize

Numerous 13CO2 labeling studies have traced the flow of carbon from fresh plant exudates into rhizosphere bacterial communities. However, the succession of the uptake of carbon leaving the roots by distinct rhizosphere microbiota has rarely been resolved between microbial kingdoms. This can provide valuable insights on the niche partitioning of primary rhizodeposit consumption, as well as on community interactions in plant-derived carbon flows in soil. Here, we have traced the flow of fresh plant assimilates to rhizosphere microbiota of maize (Zea mays L.) by rRNA-stable isotope probing (SIP). Carbon flows involving bacteria, unicellular fungi, as well as protists were observed over 5 and 8 days. Surprisingly, labeling of Paraglomerales and several bacteria including Opitutus, Mucliaginibacter and Massilia spp. was especially apparent in soil surrounding the strict rhizosphere after 5 d. This highlights the central role of arbuscular mycorrhizal fungi (AMF) as a shunt for fresh plant assimilates to soil microbes not directly influenced by root exudation. Distinct trophic webs involving different flagellates, amoeba and ciliates were also observed in rhizosphere and surrounding soil, while labeling of filamentous saprotrophic Ascomycota or Basidiomycota was not apparent. This challenges the proposed “sapro-rhizosphere” concept and demonstrates the utility of rRNA-SIP to disentangle inter-kingdom microbial relationships in the rhizosphere.

Role of arbuscular mycorrhizal fungi as biocontrol agents against Fusarium verticillioides causing ear rot of Zea mays L. (Maize)

The protection of plants from pathogens results to better performances in growth and yield characters. Therefore, the efficacy of Glomus clarum and G. deserticola as biocontrol agents against Fusarium verticillioides (AKR 05, ILR 06 and ERW 05) strains on maize T2L COMP.4 was investigated. Concentration 10 g (20 spores), 20 g (48 spores) and 30 g (72 spores) of Glomus clarum and G. deserticola were inoculated separately into 8 kg of soil at four weeks after planting (WAP), with a control (0 g). In addition, spore suspension (1.0 × 106 spores/mL) of Fusarium verticillioides was inoculated at 8 WAP. The treatments were arranged in a completely randomized design with three replicates. The pathogenic effects of F. verticillioides on plant height and shoot weight were significantly reduced by the application of 20 g of G. clarum and 30 g of G. deserticola. Also, 10 g of both G. clarum and G. deserticola significantly enhanced the production of the husk cover, while 30 g G. clarum and G. deserticola significantly reduced the severity of maize ear rot. Therefore, 30 g G. clarum and G. deserticola had biocontrol potential against Fusarium verticillioides. Hence, they are recommended to maize producers in Fusarium endemic agro-ecological zones for optimal production.

Arbuscular mycorrhizal fungi and the associated bacterial community influence the uptake of cadmium in rice

Cadmium (Cd)-contaminated rice imposes severe health risks to human. The present study investigated the role of arbuscular mycorrhizal fungi (AMF) in sculpting the rhizospheric bacterial community, and the potential effects on the Cd uptake by rice. AMF Funneliformis mosseae (Fm) or Rhizophagus intraradices (Ri) were inoculated to rice grown in soils spiked with 0 or 10 μM Cd. Initial Cd concentration in soil was 0.18 mg/kg. AMF colonization rate, plant biomass, Cd content in rice, soil properties, rice Cd transporters (Nramp5 and HMA3) and soil bacterial community were analysed. Both AMF decreased (P < 0.05) root and shoot Cd concentrations, especially for Ri treatment. The higher relative abundance of Actinobacteria (mostly from genus Arthrobacter) observed in Ri treatment probably absorbed Cd in soil, and hence decreased the Cd availability for rice. Expression of genes Nramp5 and HMA3 in root were lower in Ri treatment, but higher in Fm treatment. The gene expressions were in line with the results of lower root Cd content in Ri treatment, and higher in Fm treatment. The present study firstly revealed that AMF can reduce rice Cd uptake by changing the expression of Cd transporters and soil bacterial community in a pot experiment. Effects of plants-bacteria-fungi interaction on both plant productivity and toxicants uptake deserved further study.

Intercropping with sunflower and inoculation with arbuscular mycorrhizal fungi promotes growth of garlic chive in metal-contaminated soil at a WEEE-recycling site

Heavy metal (HM) pollution in agricultural soils due to the recycling of waste electrical and electronic equipment (WEEE) has become a serious concern, but most farmers cannot afford the economic losses of fallow land during remediation. Thus, it is imperative to produce low-HM crops while remediating the contaminated soils. A 17-week pot experiment was conducted to investigate the growth and HM (Cd, Cu, Pb, Cr, Zn, and Ni) acquisition of garlic chives (Allium tuberosum Rottl. ex Spreng.) intercropped with sunflower (Helianthus annuus L.) and inoculated with (I+M) or without (I-M) the arbuscular mycorrhizal (AM) fungus Funneliformis caledonium on a severely HM-contaminated soil that was collected from a WEEE-recycling site. Compared with the monoculture control, the I-M treatment significantly (P < 0.05) decreased Cd, Cu, Cr, Zn, and Ni concentrations in the shoots of chives through rhizosphere competition and HM (except Cr) transfer from the root to the shoot of chives, and increased the average shoot fresh weight (i.e., yield) of chives by 794% by alleviating HM toxicity. Compared with the I-M treatment, the I+M treatment significantly increased soil phosphatase activity as well as root mycorrhizal colonization of both sunflower and chives. The I+M treatment had no effect on the tissue P concentration of sunflower but elevated the average dry biomass (shoot plus root) and P acquisition level of sunflower by 179% and 121%, respectively. In addition, the I+M treatment significantly increased the P concentration in the root rather than in the shoot of chives and significantly increased the level of P acquisition by chives, increasing the average yield of chives by 229%. Simultaneously, the I+M treatment significantly increased the level of HM (except Cd) acquisition by sunflower, enhancing the rhizosphere competition by sunflower over chives, and further reducing the transfer of all six HMs from root to shoot in the chives, and inducing significant decreases in chive shoot HM concentrations compared with the monoculture control. Furthermore, the I+M treatment decreased the average total concentrations and increased the average DTPA-extractable concentrations of soil HMs. The results demonstrate the multifunctional role of AM fungi in the intercropping system for both vegetable production and phytoremediation on HM-contaminated soils.

Evaluation of Growth and Morphological Pattern of Mycorrhization in Cowpea [Vigna unguiculata (L.)] Fertilized With Phosphorus

Microorganisms perform important functions in the soil and, among these organisms, the role of arbuscular mycorrhizal fungi (AMF) in plant growth should be highlighted. AMF colonize the roots of most plant species and their beneficial functions in plant development include increased absorption of nutrients from the soil, especially those of low mobility such as phosphorus (P). Evaluating agricultural practices conducted by farmers, such as phosphate fertilization, and observing how they will influence AMF activity in benefiting plant growth should be prioritized. Thus, an experiment was conducted in greenhouse to evaluate the effect of phosphate fertilization on the growth of cowpea plants colonized by AMF and to know which morphological pattern of colonization prevails in their roots. Five P doses and a control treatment, without fertilization, were added to the soil. Cowpea plants respond to phosphate fertilization up to the dose of 240.50 mg P kg-1 soil, for shoot dry mass and in the dose of 150 mg P kg-1 soil, for plant height. The morphological pattern observed in the roots was the intermediate type, characterized by the presence of intra and intercellular hyphae and vesicles, and there was no influence of phosphate fertilization on morphology. High P contents added to the soil led to a reduction in mycorrhizal colonization in cowpea roots.

Recent Trend: Is the Role of Arbuscular Mycorrhizal Fungi in Plant-Enemies Performance Biased by Taxon Usage?

The potential for arbuscular mycorrhizal (AM) fungi to confer resistance and provide bioprotection against plant pests and pathogens is intriguing to biologists studying at many levels of biological organization, including the organismal, population, and community levels. In recent years, there has been a growing trend to experimentally test the role of AM-fungi in plant-enemy performance. Yet, it remains unclear whether taxon usage in these studies are biasing the results. Here I conducted a survey, while strictly focusing on the effect of AM-fungi, with respect to plant-enemies performance. I found 25% of case studies did not observe a reduction in performance. Interestingly, 75% of studies featured a single AM-fungal taxon, as opposed to multiple taxa. What is even more compelling, 72% of studies featured Rhizophagus irregularis and Funnelformis mosseae. These findings demonstrate a lack of AM-fungal diversity in this area of research and a need for expansion in mycorrhizal taxon usage, to understand more fully the significance of mycorrhizal application in conferring bioprotection.

Role of arbuscular mycorrhizal fungi and Pongamia pinnata for revegetation of tropical open-pit coal mining soils

Open-pit coal mining activities may cause forest and environmental degradation. Thus, forests need to be reclaimed and revegetated after coal mining. This study aimed to determine the combined effects of arbuscular mycorrhizal fungi (AMF) inoculation on the revegetation of postcoal-mining lands with Pongamia pinnata. This completely randomized study was conducted for 6 months in a greenhouse. The first factor consisted of four different levels based on soil medium type: forest soil, mined-out soil, overburdened soil, and landfill soil. The second factor consisted of three levels based on three different dosages of AMF: control, 2 g of AMF, and 4 g of AMF. Open-pit coal mining activities in East Kalimantan caused serious land degradation in tropical ecosystem. Revegetation with P. pinnata accelerated land reclamation by passing the land preparation stage and decreased the costs of land preparation. Forest soil was the optimal medium for the growth of P. pinnata seedlings. However, when the seedlings were planted in degraded soil of mining, their average height, diameter, and total biomass decreased drastically. The inoculation of 2 g AMF colonized the root and therefore improved growth of seedling. This result may reduce cost of chemical fertilizer. AMF inoculation improved Fe absorption by 11.7% that was higher than that under control, whereas 90.4% of the assimilated Fe was retained in plant roots. Revegetation by exotic fast-growing pioneer legume species of P. pinnata and application of AMF drastically improved some chemical soil properties that suitable for rehabilitation program in tropical post-mining areas.

The role of arbuscular mycorrhiza in mercury and mineral nutrient uptake in maize

This work aimed to study the role of arbuscular mycorrhizal fungi (AMF) in Hg and major mineral nutrient uptake and tissue localization of these elements in the roots of maize plants. Maize plants were grown in pots filled with non- and Hg-contaminated substrate (50 μg Hg g−1 as HgCl2) and inoculated with two types of AMF inocula: a) Glomus sp. originating from Hg-polluted soil of a former Hg smelting site in Idrija, Slovenia, and b) commercial AM inoculum Symbivit. Controls were inoculated by corresponding bacterial extracts only. Tissue localization of Hg and major mineral nutrients was performed by laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) on cryofixed and freeze-dried root cross-sections. AMF colonization increased plant biomass in non-contaminated substrate, while this effect was not seen in Hg-contaminated substrate. Hg increased total plant biomass more than AMF inoculation, possibly through hormetic effects. AMF increased Hg uptake into the roots, as well as Hg transfer to the shoots. AMF affected plant mineral nutrient uptake, depending on the type of AMF inoculum and the presence of Hg. In the roots, Hg was mainly localized in rhizodermis and endodermis, followed by the cortex and the central cylinder. Higher Hg concentrations were detected in the central cylinder of AM plants than in that of the controls, pointing to a higher Hg mobility and potential bioavailability in AMF inoculated plants.

The photoprotective role of arbuscular mycorrhizal fungi (AMF) in cucumber seedlings under cold stress

The photoprotective role of arbuscular mycorrhizal fungi (AMF) in cucumber seedlings under cold stress

Transcriptional Changes in Mycorrhizal and Nonmycorrhizal Soybean Plants upon Infection with the Fungal Pathogen Macrophomina phaseolina.

Macrophomina phaseolina is a soil-borne fungal pathogen with a wide host range that causes charcoal rot in soybean [Glycine max (L.) Merr.]. Control of the disease is a challenge, due to the absence of genetic resistance and effective chemical control. Alternative or complementary measures are needed, such as the use of biological control agents, in an integrated approach. Several studies have demonstrated the role of arbuscular mycorrhizal fungi (AMF) in enhancing plant resistance or tolerance to biotic stresses, decreasing the symptoms and pressure caused by various pests and diseases, including M. phaseolina in soybean. However, the specific contribution of AMF in the regulation of the plant response to M. phaseolina remains unclear. Therefore, the objective of the present study was to investigate, under strict in-vitro culture conditions, the global transcriptional changes in roots of premycorrhized soybean plantlets challenged by M. phaseolina (+AMF+Mp) as compared with nonmycorrhizal soybean plantlets (-AMF+Mp). MapMan software was used to distinguish transcriptional changes, with special emphasis on those related to plant defense responses. Soybean genes identified as strongly upregulated during infection by the pathogen included pathogenesis-related proteins, disease-resistance proteins, transcription factors, and secondary metabolism-related genes, as well as those encoding for signaling hormones. Remarkably, the +AMF+Mp treatment displayed a lower number of upregulated genes as compared with the -AMF+Mp treatment. AMF seemed to counteract or balance costs upon M. phaseolina infection, which could be associated to a negative impact on biomass and seed production. These detailed insights in soybean-AMF interaction help us to understand the complex underlying mechanisms involved in AMF-mediated biocontrol and support the importance of preserving and stimulating the existing plant-AMF associates, via adequate agricultural practices, to optimize their agro-ecological potential.

Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants

Ecological consequences of low-dose radioactivity from natural sources or radioactive waste are important to understand but knowledge gaps still remain. In particular, the soil transfer and bioaccumulation of radionuclides into plant roots is poorly studied. Furthermore, better knowledge of arbuscular mycorrhizal (AM) fungi association may help understand the complexities of radionuclide bioaccumulation within the rhizosphere. Plant bioaccumulation of uranium, thorium and radium was demonstrated at two field sites, where plant tissue concentrations reached up to 46.93 μg g−1 238U, 0.67 μg g−1 232Th and 18.27 kBq kg−1 226Ra. High root retention of uranium was consistent in all plant species studied. In contrast, most plants showed greater bioaccumulation of thorium and radium into above-ground tissues. The influence of specific soil parameters on root radionuclide bioaccumulation was examined. Total organic carbon significantly explained the variation in root uranium concentration, while other soil factors including copper concentration, magnesium concentration and pH significantly correlated with root concentrations of uranium, radium and thorium, respectively. All four orders of Glomeromycota were associated with root samples from both sites and all plant species studied showed varying association with AM fungi, ranging from zero to >60% root colonisation by fungal arbuscules. Previous laboratory studies using single plant-fungal species association had found a positive role of AM fungi in root uranium transfer, but no significant correlation between the amount of fungal infection and root uranium content in the field samples was found here. However, there was a significant negative correlation between AM fungal infection and radium accumulation. This study is the first to examine the role of AM fungi in radionuclide soil-plant transfer at a community level within the natural environment. We conclude that biotic factors alongside various abiotic factors influence the soil-plant transfer of radionuclides and future mechanistic studies are needed to explain these interactions in more detail.

Mycorrhiza-Induced Alleviation of Plant Disease Caused by Clavibacter michiganensis Subsp. Michiganensis and Role of Ethylene in Mycorrhiza-Induced Resistance in Tomato

The protective role of arbuscular mycorrhizal fungi (AMF) against the phytopathogen Clavibacter michiganensis subsp. michiganensis (Cmm) was examined in tomato plants. Seven different AMF isolates were used to determine which ones were able to induce effectively resistance against Cmm. Stems of seven-week tomato plants were infected with Cmm, then a disease severity index (DSI) was determined during the next three weeks. In addition to different responses to mycorrhizal inoculation, three levels of responses to the bacterial disease were recognized in treatments. Plants inoculated with Rhizophagus irregularis (Ri) showed both the highest colonization and the highest induced resistance to Cmm while the effect of Funneliformis mosseae, Gigaspora margarita and Claroideoglomus claroideum on mycorrhizal colonization and on the induced resistance were intermediate and high, respectively. Subsequently, Ri was chosen to inoculate ethylene-insensitive tomato mutant line Never ripe (Nr) and its background (Pearson) to investigate the possible role of ethylene (ET) in the mycorrhiza-induced resistance (MIR). The results showed that Ri could induce systemic resistance against Cmm in the Pearson background, whereas ET-insensitivity in Nr plants impaired MIR. These results suggest that ET is required for Ri-induced resistance against Cmm. To our knowledge, this is the first study to examine the effect of different AMF isolates on the response of tomato plants to Cmm and involvement of ET in MIR against Cmm.

Arbuscular mycorrhizal fungi alleviate arsenic toxicity to Medicago sativa by influencing arsenic speciation and partitioning

In a pot experiment, Medicago sativa inoculated with/without arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis were grown in four levels (0, 10, 25, and 75 mg/kg) of arsenic (As)-polluted soil to investigate the influences of AM symbiosis on plant As tolerance. The results showed that mycorrhizal inoculation significantly increased plant biomass, while As addition decreased mycorrhizal colonization and hyphal length density. Mycorrhizal inoculation dramatically improved plant phosphorus (P) nutrition, restricted As uptake and retained more As in roots by upregulating the expression of the AM-induced P transporter gene MsPT4 and the metallothionein gene MsMT2. High soil As content downregulated MsPT4 expression. Dimethylarsenic acid (DMA) was detected only in the shoots of mycorrhizal plants, indicating that AM fungi likely play an essential role in As detoxification by biological methylation. The present investigation allowed deeper insights into the As detoxification mechanisms of AM associations and demonstrated the important role of AM fungi in plant resistance under As-contaminated conditions.

Improvement of plant performance under water deficit with the employment of biological and chemical priming agents

AbstractDrought represents one of the major constraints on agricultural productivity and food security and in future is destined to spread widely as a consequence of climate change. Research efforts are focused on developing strategies to make crops more resilient and to mitigate the effects of stress on crop production. In this context, the use of root-associated microbial communities and chemical priming strategies able to improve plant tolerance to abiotic stresses, including drought, have attracted increasing attention in recent years. The current review offers an overview of recent research aimed at verifying the role of arbuscular mycorrhizal fungi and chemical agents to improve plant tolerance to drought and to highlight the mechanisms involved in this improvement. Attention will be devoted mainly to current knowledge on the mechanisms involved in water transport.

Prediction of the distribution of arbuscular mycorrhizal fungi in the metal(loid)-contaminated soils by the arsenic concentration in the fronds of Pteris vittata L.

The ecological role of Arbuscular mycorrhizal fungi (AMF) has been widely reported to help Pteris vittata, an arsenic (As) hyperaccumulator, to effectively clean up As from contaminated environments. However, there is little information available on AMF community structures of in natural As-contaminated soils and their changing pattern along soil As concentration gradient, as well as their best predictor of environmental variables. In this study, soil samples from four sites with different As concentrations in Hunan Province of China were collected. Illumina MiSeq sequencing was used to investigate AMF community in the rhizosphere soils of P. vittata. Redundancy analysis (RDA) and mantel tests were used to determine the significance of environmental variables that may affect AMF community composition. A total of 95 OTUs were identified, with Glomeraceae, Gigasporaceae, Acaulosporaceae, and Scutellosporaceae shared by all sampling sites. Among Glomeraceae and Glomus were the dominant family and genus, respectively. The highest value of Shannon index was found when As concentration in soil was 147.92 mg/kg (site 2, p < 0.05). RDA and mantel tests indicated that As concentrations in fronds of P. vittata (As-F) and bioconcentration factors (BCF) were significantly related to the succession of AMF community. As-F was the key environmental variable that can predict the shifts of AMF community structures in the rhizosphere of P. vittata at As-contaminated sites. This research offers preliminary insight into AMF communities in the rhizosphere of P. vittata, which is of great help toward predicting and managing microbiome for the better agroecosystem outcomes.

The role of arbuscular mycorrhizal fungi in the bioprotection of ash gourd (Benincasa hispida) against damping off disease

This experiment was aimed to determine the disease suppressive effect of arbuscular mycorrhizal fungi (AMF) to control the damping off disease of ash gourd (Benincasa hispida) seedlings caused by Sclerotium rolfsii, Fusarium oxysporum and Rhizoctonia solani. The virulent strains of S. rolfsii, F. oxysporum and R. solani were isolated before setting the experiment for integration of arbuscular mycorrhiza with ash gourd. Arbuscular mycorrhiza was collected from the rhizosphere of trap crop sorghum. Seedlings inoculated with arbuscular mycorrhiza had significantly lower incidence (p