Indigenous Arbuscular Mycorrhizal Fungi Research Articles

Molecular genetic characterization of arbuscular mycorrhizal fungi associated with upland rice in Bangladesh

Understanding the community composition and diversity of arbuscular mycorrhizal fungi (AMF) in agricultural ecosystems is important for exploring their potential for use in sustainable crop production. In this study, we collected rice root samples from upland rice fields under different agricultural practices in four districts of Bangladesh (Khagrachori, Rangamati, Chattogram, and Bandarban) to estimate the AMF colonization rate and to investigate the taxonomic diversity and community composition of indigenous AMF by high-throughput Illumina amplicon sequencing. The AMF colonization rates of the rice root samples ranged between 14 and 47%, and were positively correlated with the soil pH (4.58–5.93), suggesting that more AMF colonization is likely to form under slightly acidic conditions. This result suggests that AMF colonization rate in upland rice roots might be affected by soil pH; however, no significant correlation with soil available phosphorus contents was observed. In total, eight different AMF genera were detected by amplicon sequencing. Glomus and Paraglomus were found to be the dominant genera in all the regions, followed by Scutellospora, Acaulospora, Claroideoglomus, Diversispora, Gigaspora, and Archaeospora. Shannon’s diversity index and Pielou’s evenness were significantly higher in the Bandarban district than the other districts, whereas Faith’s phylogenetic diversity and richness showed no significant difference between the four districts. The beta diversities of AMF community composition based on the Bray-Curtis dissimilarities were significantly differentiated among the districts. The soil available phosphorus contents were significantly correlated with the AMF beta diversities between the four districts. This is the first study to report on the AMF community composition and diversity in upland rice roots and on how AMF communities are affected by the soil chemical properties in different locations in Bangladesh.

Arbuscular mycorrhizal status of Erythrina brucei in different land use types in Ethiopia

Erythrina brucei is a leguminous tree commonly used in agro-forestry practices in southern and southwestern Ethiopia. It has desirable agro-forestry attributes that make it a good candidate for agro-forestry systems. However, there is a scarcity of information regarding species diversity and spore density of arbuscular mycorrhizal fungi (AMF) associated with E. brucei growing in different land use types. Therefore, this study was initiated to determine species diversity and richness in trap cultures of AMF associated with E. brucei growing in different geographic locations in various land use types of Ethiopia. Soil samples were collected from various E. brucei growing areas with different land use patterns. Trap culture was established using a portion of each soil sample by planting E. brucei as the host plant. AMF spore extraction was carried out in field and trap culture soils, and AMF species identification was done using spore morphology. Erythrina brucei root colonization with AMF structures was studied using trap culture, and AMF spore density in both field and trap culture soil samples was determined. A total of 11 AMF genera and 33 AMF species were recovered. The highest number of genera was recovered from forest land use type at Rebu Gebeya, followed by Adiskdam, live fence land use type. Glomus and Acaulospora were the dominant AMF genera covering 73% of the samples and contained 10 and 9 AMF species, respectively. All the soil samples contained indigenous AMF spore populations regardless of their origin and land use types. The highest mean AMF spore density in a field soil sample was recorded at a farmland in Bodite (280 spores 100 g−1 of dry soil), while the lowest was from Hossana (172 spores 100 g−1of dry soil). However, the highest mean AMF spore density in trap culture was detected from a farm land at Humbo (715 spores 100 g−1 of dry soil) and the lowest from Dhakallo (217 spores 100 g−1 of dry soil). Direct extraction of AMF from field soil samples showed lesser AMF spore density compared with trap culture in the same soil sample. All E. brucei root segments were colonized with the AMF structures, and the colonization status ranged from 34.4% to 49.1%. Both geographic location and land use type significantly affected AMF species richness (p < 0.05). Undisturbed land use types were characterized by high species richness. The soil pH and available phosphorus were negatively correlated to AMF spore density (p < 0.05), but AMF root colonization did not show any significant correlation. Moreover, significant correlations were also not observed between spore number and root colonization, and available phosphorus and root length colonization. We conclude that diverse and dominant AMF genera inhabited the rhizosphere of E. brucei, which can be used for the enhancement of host plant growth. To explore AMF species diversity and richness across geographic location and land use types in detail enhanced area coverage and the combination of both direct field soil and trap culture techniques are recommended.

Effect of single and mixed inoculation of arbuscular mycorrhizal fungi and phosphorus fertilizer application on corn growth in calcareous soil

Abstract. Ishaq L, Adu Tae ASJ, Airthur MA, Bako PO. 2021. Effect of single and mixed inoculation of arbuscular mycorrhizal fungi and phosphorus fertilizer application on corn growth in calcareous soil. Biodiversitas 22: 1920-1926. Low availability of soil phosphorus (P) in calcareous soil in West Timor has become a constraint in improving plant productivity. A field experiment was carried out in the calcareous soil to investigate the effect of single and mixed indigenous arbuscular mycorrhizal fungi (AMF) inoculation and P fertilizer application on growth and yield of corn in Kupang District, East Nusa Tenggara Timur Province, Indonesia. The experiment was laid out in a split-plot design consisting of indigenous AMF inoculation as the main plots and inorganic P fertilizer rates as the sub-plot treatments. The main plot treatments were: without AMF inoculation (M0), inoculated with single AMF inoculum (M1) and inoculated with mixed AMF inocula (M2). Sub-plots consisted of four P rates namely 25% (P1), 50% (P2), 75% (P3) and 100% (P4) of the recommended inorganic superphosphate dose of 200 kg SP36 ha-1. The results showed that there were significant interactions between AMF inoculation and P fertilizer dose on AMF spore density, AMF colonization and soil available P. Results indicated a strong correlation between AMF colonization and soil available P. Inoculation of both M1 and M2 significantly increased soil available P, plant growth and yield compared to the uninoculated plant. Spore production in the two AM responded differently to P fertilizer. Low doses of inorganic P fertilizer favored spore production in M1, whereas P fertilizer sporulation in M2 was adversely affected. The percentage of AMF root colonization of M1 and M2 decreased with an increase in P fertilizer applied. Further studies need to be conducted to evaluate the effectiveness of indigenous AMF in improving plant yield at low level of inorganic fertilizer application to achieve more sustainable agricultural practice in the region.

Survival of a commercial AM fungal inoculant and its impact on indigenous AM fungal communities in field soils

Arbuscular mycorrhizal fungi (AMF) are being promoted as commercial biofertilizers (bioinoculants) for sustainable agriculture. However, little is known about the survival of AMF inoculants in soil and their impacts on indigenous AMF communities under multiple cropping conditions. A three-year study was conducted at four field-sites across semiarid to subhumid climate zones in the Saskatchewan prairie, Canada. A commercial AMF inoculant containing Rhizophagus irregularis was applied at seeding in the first year of the study in 2011 to the host crop pea (Pisum sativum), grown in open-ended soil cores. The persistence of the inoculant and subsequent phylogenetic changes in the community of the indigenous AMF taxa were assessed for three consecutive cropping seasons (2011–2013), during which wheat (Triticum aestivum) was grown in year two and pea in year three. At harvest of each year, the AMF community was assessed using 18S rRNA gene pyrosequencing of AMF trap roots. A total of 131 AMF OTUs (year 1: 54, year 2: 28, year 3: 49 OTUs, respectively), representing eight genera (Glomus, Funneliformis, Claroideoglomus, Diversispora, Paraglomus, Rhizophagus, Septoglomus, and Archaeospora) was detected. Phylogenetic analysis showed the inoculant could be detected to the end of third cropping season (i.e., 27-month after inoculation) at the Swift Current and Outlook field-sites, but was only detected at the Scott and Melfort field-sites to the end of the first (3-month) and second (15-month) growing seasons, respectively. The commercial inoculant caused alterations (taxa suppression, stimulation, and exclusion) of specific members of the indigenous AMF (abundance and diversity) after the first crop season at Swift Current and after all three seasons at Outlook, Scott, and Melfort sites. Multivariate statistical analysis revealed the survival of the commercial inoculant, and the subsequent changes in the indigenous AMF taxa were dependent on soil environments.

Arbuscular mycorrhizal enhancement of phosphorus uptake and yields of maize under high planting density in the black soil region of China

Arbuscular mycorrhizal (AM) symbioses are an attractive means of improving the efficiency of soil phosphorus (P) that difficult to be used by plants and may provide a sustainable way of maintaining high yields while reducing P applications. However, quantifying the contribution of indigenous AM fungi on phosphorus uptake and yields of maize (Zea mays L.) under field conditions is not particularly clear. Mesh-barrier compartments were applied to monitor the distribution of hyphal P uptake throughout the experimental period under different planting densities and soil depths, over two consecutive years. AM symbioses enhanced plant P-acquisition efficiency, especially during the silking stage, and hyphae of AM fungi was assessed to contribution 19.4% at most to total available P content of soil. Moreover, the pattern of AM depletion of soil P generally matched shoot nutrient demand under the high planting density, which resulted in significantly increased yield in 2014. Although the hyphal length density was significantly decreased with soil depth, AM fungi still had high potential for P supply in deeper soil. It demonstrates the great potential of indigenous AM fungi to maize productivity in the high-yield area of China, and it would further provide the possibility of elimination P fertilizer applications to maintain high yields.

Odgovor industrijske rajčice na primjenu arbuskularnih mikoriznih gljiva u uvjetima konvencionalne proizvodnje

The potential effect of pre-inoculation of processing tomato (Solanum lycopersicum L.) plants with arbuscular mycorrhizal fungi (AMF) on yield and fruit properties was investigated in conventional production. Tomato seeds were sown in seedling trays filled with a substrate non-inoculated (AMF-) or inoculated (AMF+) by selected mycorrhizal strains. Seedlings were transplanted in Terra rossa soil and grown in conditions with mineral fertilization and irrigation. Tomato fruits were sampled at harvest. Tomato plants under both treatments had high levels of mycorrhizal colonization, due to applied inoculum (AMF+) or indigenous (AMF-) inoculum present in the soil. Applied AMF+ treatment increased P and decreased K content in tomato fruits. Content of trace elements such as As and V significantly increased, while Pb content significantly decreased in the fruits of AMF+ when compared to the AMF- treatment. No significant effect of AMF+ treatment was observed on yield, fruit quality (soluble solids, pH, total acidity, fruit firmness), lycopene and antioxidant activity of tomato fruits. The overall results suggest that processing tomato is highly susceptible to the indigenous AMF, while seedlings inoculation with selected AMF improves only total phenolic and P fruit content. This means that AMF have a potential application in commercial processing tomato production, however a targeted adaptation of management decissions is required for more extensive results.

Occurrence of indigenous arbuscular mycorrhizal fungi associated with the rhizosphere of the naidí palm in Colombia

In the Colombian Pacific region, the naidí palm, Euterpe oleracea Mart. (Arecaceae) produces high-value fruit due to its high nutritional quality, representing an economic benefit to the families of the region. In this study, we evaluated the occurrence of arbuscular mycorrhizal fungi (AMF) in the rhizospheric soil of E. oleracea in Bajo Calima, Buenaventura. This is the first report of AMF of E. oleracea in Colombia. Surface soil samples (0-10 cm) were collected in two areas (L1 - under the influence of rice cropping and L2 - tropical rainforest). The chemical properties of the soil, the number of spores, and the mycorrhizal colonization in the root were established. We observed low mycorrhizal colonization (10 % in L1 and 4 % in L2), negatively correlated to the content of available phosphorus in the soil. However, significant differences between areas (p = 0.009) were recorded. Globose, subglobose, and ovoid spores were observed (660 and 791 spores/100 g soil in L1 and L2, respectively). Spores are represented in several morphotypes that can be classified as Claroideoglomeraceae, Glomeraceae, Diversisporaceae, Paraglomeraceae, and Ambisporaceae. High available P content (13.1 mg/kg in L1 and 20.5 mg/kg in L2), among other edaphic factors associated, could explain the low mycorrhizal colonization observed, especially when there are not enough studies linking ecological factors with AMF dynamics in tropical rainforests. On the other hand, spore abundances reported in the rhizospheric soil of E. oleracea suggest a high potential to explore indigenous AMF activity in the Colombian Pacific region to achieve sustainable production practices in this palm.

Inoculation with selected indigenous mycorrhizal complex improves Ceratonia siliqua's growth and response to drought stress.

In the current study, we investigated the impact of inoculation with a selected indigenous arbuscular mycorrhizal fungi (AMF) complex on the growth and physiology of carob plants at increasing levels of watering (25, 50, 75 and 100% field capacity). The following growth and stress parameters were monitored in carob seedlings after 6 months of growth and 2 months of applied drought stress: fresh and dry weight, root and shoot lengths, leaf surface area, relative water content, stomatal conductance and membrane stability. Chlorophyll a and b, total soluble sugars, proline and protein contents were also determined along with the activities of stress enzymes: Catalase, Peroxidase and Superoxide dismutase. The obtained results indicate that inoculation with the indigenous AMF complex has a positive impact on the plant’s growth as all the assessed parameters were significantly improved in the mycorrhizal plants. Additionally, our results show that mycorrhization contributes to the minimization of the impact of drought stress on the carob plants and allows a better adaptation to dry conditions.

The Role of Arbuscular Mycorrhizal Fungi Against Root-Knot Nematode Infections in Coffee Plants

Coffee (Coffea arabica) is one of the most important tropical crops in the world, and root-knot nematode (Meloidogyne spp.) infections are one of the main factors that negatively affect crop yields throughout the South American region. This study aimed to evaluate the role of indigenous arbuscular mycorrhizal fungi against root-knot nematode infections in coffee plants grown under different soil conditions in the Peruvian Amazon. The experimental design was a 3A × 2B × 4C factorial scheme with 24 treatments. Each experimental unit consisted of six coffee plants, with three replicates in randomized blocks, totaling 18 coffee plants per treatment. The studied factors were soil conditions (A), types of coffee propagation (B), and arbuscular mycorrhizal fungi consortia (C). The data were statistically examined by three-way analysis of variance, and the Tukey HSD test was applied for multiple comparisons of group means. Mycorrhiza-induced tolerance was confirmed against root-knot nematodes, as the severity of infection was significantly lower in mycorrhizal roots, with an average reduction of 52.5%, 38.5% and 38.3% in coffee plants inoculated with Huall-pache, Do-cat, and Mo-cat, respectively. Furthermore, the effects on plant growth and biological control vary depending on the diversity of arbuscular mycorrhizal fungi consortia, soil conditions, and type of propagation. This study therefore demonstrates that the inoculation of coffee plants with indigenous arbuscular mycorrhizal fungi prior to field establishment promotes coffee plant growth after root-knot nematode infections.

Feremycorrhizal symbiosis confers growth and nutritional benefits to mycorrhizal and non-mycorrhizal crops

Feremycorrhiza (FM) is a newly discovered plant-fungus symbiosis that improves plant growth and nutrition without development of interface structures (i.e. no root colonization). The host plant range in the FM symbiosis is currently unknown. We report the results of controlled environment investigations characterizing the capability of crops to establish FM symbiosis with Austroboletus occidentalis, along with comprehensive in vitro studies to unravel the functional mechanisms underlying the phosphorus (P) nutritional benefits conferred to host plants. After 16 weeks of growth in a natural low-nutrient field soil (containing indigenous microbes), two mycorrhizal crops [wheat (Triticum aestivum) and barley (Hordeum vulgare)], and the non-mycorrhizal crop canola (Brassica napus) inoculated with A. occidentalis had significantly higher shoot biomass compared to the control (non-inoculated) plants. The FM symbiosis also led to significant grain yield increases in wheat (by 54%) and barley (by 37%) compared to the control plants, while canola was harvested before setting seeds due to slow growth under nutrient deficiency. In all crops, the FM symbiosis significantly improved the shoot nutrient content, including that of P, potassium and magnesium. Total nitrogen accumulation (shoot + grain content) was also significantly higher in all inoculated vs control crops. Inoculated treatments had reduced soil pH compared to the control, which was attributed to fungal activities in soil, leading to greater nutrient (P, in particular) availability to host plants. Presence of A. occidentalis in soil did not affect root colonization by indigenous arbuscular mycorrhizal fungi in wheat and barley, and no root colonization was detected in canola. Our in vitro studies demonstrated the solubilization, by A. occidentalis, of the water-insoluble P forms, including calcium phosphate (CaP, as hydroxyapatite), iron phosphate (FePO4), and aluminium phosphate (AlPO4) via exudation of organic acid anions (mainly oxalate, along with citrate and fumarate). The 31P nuclear magnetic resonance (NMR) spectroscopy revealed the presence of similar P species (dominated by orthophosphate and long-chain inorganic polyphosphates) in the agar-based media supplemented with different P forms (KH2PO4, CaP, FePO4 or AlPO4), indicating that all three water-insoluble P compounds were solubilized and transformed by the FM fungus. Furthermore, our in vitro studies revealed that the FM fungus converted a large proportion of the solubilized P (free orthophosphate) into long-chain inorganic polyphosphates (making up to 51% of total P in the media). The results demonstrated that the three important grain crops, regardless of their capacity to support arbuscular mycorrhizae, could get the growth and nutritional benefits from the FM symbiosis, emphasizing the potential of A. occidentalis as a novel fungal biofertilizer for agricultural crops.

Poultry Litter Biochar Increases Mycorrhizal Colonisation, Soil Fertility and Cucumber Yield in a Fertigation System on Sandy Soil

There is a continuing argument about the benefits of biochar on arbuscular mycorrhizal (AM) symbiosis, crop growth, yield, and fertility of soil. There is also limited research on the effects of biochar on AM colonization, cucumber yield, and soil fertility improvement. Therefore, this investigation aimed to determine the impact of poultry litter biochar (PLB) on colonization of roots by indigenous AM fungi in agricultural soil and their contribution to cucumber yield, nutrition, and soil fertility improvement. A field trial was conducted to assess the effect of PLB combined with compound poultry manure (CPM) and nitrophos (NP) fertilizer to investigate the response of treatments on nutrient-deficient sandy soils. Plant growth responses to biochar showed better plant growth and yield of cucumber. Application of biochar with and without CPM and NP reduced the negative impact of nutrient deficiency stress on cucumber growth. AM fungal colonization, soil fertility, and cucumber yield were improved with the combined application of biochar, CPM, and NP fertilizer. Post-harvest, soil C, N, P, K, Ca, Mg, S, Zn, Cu, Fe, and Mn increased with application of biochar applied with CPM and NP. Biochar application with CPM and NP also increased the percent root colonization of cucumber. Use of biochar with CPM and NP has the potential to improve plant growth, yield, nutrient uptake, and soil fertility. Further studies in various agro-ecological conditions would help utilize this technology in sustainable crop production.

Co-application of indigenous arbuscular mycorrhizal fungi and nano-TiO2 reduced Cd uptake and oxidative stress in pre-flowering cowpea plants

The symbiotic association between plant roots and arbuscular mycorrhizal fungi (AMF) promotes plant growth, and reduces toxic metals accumulation in plants. In this study, the effect of inoculation with indigenous AMF ( Glomus Spp.) and co-application of AMF and nano-TiO 2 on Cd accumulation on activities of stress enzymes in cowpea at pre-flowering stage was examined. Soil substrates were spiked with either Cd (10 mg/kg) and inoculated with either AMF suspension (7 ml) or AMF+ n TiO 2 (200 mg/kg). The results showed that inoculation with AMF and AMF+ n TiO 2 promoted germination and chlorophyll contents by at least 12% and 45%, respectively. As envisaged, AMF+ n TiO 2 reduced uptake and decreased translocation of Cd to above-ground biomass better than inoculation solely with AMF. In the aspect of Cd toxicity assessed by enzymes activity, sole AMF inoculation and AMF+ n TiO 2 had varied effects on the stress enzymes activity. However, n TiO 2 interacted synergistically with AMF to improve stress tolerance by reducing the lipid peroxidation in plants (in term of the amount of malondialdehyde) more than sole inoculation with AMF. In conclusion, the present study demonstrated that there is stimulatory effect of nano-TiO 2 on the activity of AMF in alleviating Cd stress in pre-flowering cowpea. • Combination of AMF and n TiO 2 reduced root uptake and translocation of Cd. • Synergistic interaction between AMF and n TiO 2 reduced MDA content. • Nano-TiO 2 portends stimulatory effect on AMF to reduce Cd toxicity.

Arbuscular Mycorrhizal Fungi and K-Humate Combined as Biostimulants: Changes in Antioxidant Defense System and Radical Scavenging Capacity in Elaeagnus angustifolia

Arbuscular mycorrhizal fungi (AMF) and potassium humate (KH) are separately known as significant biostimulants, but their combined effect on plants remains elusive. This study investigated the single and combined roles of AMF and KH on the antioxidant defense system in Russian olive (Elaeagnus angustifolia L.) leaves. Soil below the seeds was inoculated with indigenous AMF spores (Funneliformis, Claroideoglomus; 500 spores per seed). The KH (1.5 g/ per 1 kg of seed) was applied during sowing. Growth, leaf-water ratio, chlorophyll fluorescence, lipid peroxidation, H2O2 content, antioxidant enzymes, and antioxidant capacity were analyzed in treated and untreated plants. Combined AMF and KH applications had a greater recovery effect on vegetative organ growth than separate treatments. With combined treatment, plants maintained leaf water status and chlorophyll fluorescence, while peroxidation of lipid membranes and H2O2 content was reduced. Moreover, increases in superoxide dismutase and glutathione reductase activity prevented cellular damage from reactive oxygen species. Total phenolic content and antioxidant capacity values were remarkably higher in plants grown under the combined treatment. As a result, compared with their separate applications, a combination of AMF and KH enhanced the antioxidant defense system by increasing antioxidant enzymes and antioxidant capacity and, thus, could be used to enhance plant growth.

Infectivity of the palm groves arbuscular mycorrhizal fungi under arid and semi-arid climate and its edaphic determinants towards efficient ecological restoration

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in ecological restoration. To date, indigenous AMF remain unexplored but could be a potential resource for successful restoration programs. In this study, we evaluated the infectivity of AMF of five degraded oasis soils in Morocco (Marrakesh, Tafilalet, Draa, Tata-Guelmim and Figuig). Our data showed that mycorrhizal parameters; AMF spore number, MIP (mycorrhizal infectious potential) and AMF infection, in the arid palm groves soils, were more important than in the semi-arid ones. Principal component analysis (PCA) showed that the percentage of sand in the soil had a positive impact on AMF parameters, while soil available phosphorus, total nitrogen, electrical conductivity, organic matter, CaCO3 content, C/N ratio and clay percentage had a negative impact on these parameters. Results of the present study demonstrate that the mycorrhizal status of these palm groves soils is closely related to the edaphic parameters and suggest that native AMF can be used to restore ecological function of degraded oases in arid and semi-arid area.

Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

Potential of Native Plant Species and Indigenous Arbuscular Mycorrhizal Fungi in Post-mining Land Recovery and Revegetation

Potential of Native Plant Species and Indigenous Arbuscular Mycorrhizal Fungi in Post-mining Land Recovery and Revegetation

Arbuscular Mycorrhizal Fungi Associated with Rice (Oryza sativa L.) in Ghana: Effect of Regional Locations and Soil Factors on Diversity and Community Assembly

Understanding the community composition and diversity of arbuscular mycorrhizal fungi (AMF) in an agricultural ecosystem is important for exploiting their potential in sustainable crop production. In this study, we described the genetic diversity and community structure of indigenous AMF in rain-fed rice cultivars across six different regions in Ghana. The morphological and molecular analyses revealed a total of 15 different AMF genera isolated from rice roots. Rhizophagus and Glomus were observed to be predominant in all regions except the Ashanti region, which was dominated by the genera Scutellospora and Acaulospora. A comparison of AMF diversity among the agroecological zones revealed that Guinea Savannah had the highest diversity. Permutational Multivariate Analysis of Variance (PERMANOVA) analysis indicated that the available phosphorus (AP) in the soil was the principal determining factor for shaping the AMF community structure (p &lt; 0.05). We report, for the first time, AMF diversity and community structure in rice roots and how communities are affected by the chemical properties of soil from different locations in Ghana.

Arbuscular mycorrhizal fungal inoculation improves Nauclea orientalis L. growth dan phosphorus uptake in gold mine tailings soil media

Gold mine tailing soil media is characterized by low soil fertility and heavy metals toxicity. As an effort to improve the condition of gold mine tailing soil media, a revegetation experiment using Arbuscular Mycorrhizal Fungi (AMF) and soil media from gold mine tailing was conducted in the greenhouse. The objectives were to assess initial growth, P uptake and Pb reduction in Nauclea orientalis L. plants inoculated with indigenous AMF grown on gold mine tailing soil media. Three AMF fungi were used in this study, i.e. Glomus aggregatum , Glomus sp. and Acaulospora delicata. The experiment was conducted in Completely Randomized Design, having four treatments, i.e. control, G. aggregatum , Glomus sp. and A. delicata . The experiment was carried out for 3 months in a greenhouse scale. The results showed that local AMF inoculation significantly increased the height and stem diameter of lonkida by 181-213% and 284-443%, respectively, compared to control. The highest measurements of leaf’s length and width of lonkida seedlings were obtained from Glomus sp. and A. delicata treatments. Glomus sp. and A. delicata each significantly increased P levels in roots and shoots. Inoculation with G. aggregatum reduced Pb in the root and shoots parts by 74-86% and 72-76%, respectively, compared to controls. Local AMFs are potential to be developed as biological fertilizers to support revegetation in degraded lands, such as in gold mine tailing areas.

Soil phosphorus availability modifies the relationship between AM fungal diversity and mycorrhizal benefits to maize in an agricultural soil

Arbuscular mycorrhizal (AM) fungi are very abundant in many agricultural soils and are important in increasing and maintaining the sustainability of agricultural systems. However, high soil fertility, especially high available soil phosphorus (P) status, often limits AM fungal development in intensively managed agricultural systems and results in the C-costs to the host plant outweighing any benefits from AM colonization. Some promising approaches can minimize negative effects on soil biota while providing the desired agricultural benefits (e.g. reduced soil tillage and organic amendments). However, the influence of these agricultural practices on the benefits of root mutualistic associations remains poorly understood. Here, we collected indigenous AM fungi from a long-term field experiment with different application rates of cow manure and conducted a pot experiment with different soil P levels. Using high throughput sequencing we demonstrate that increasing cow manure application changed the community composition of AM fungi and reduced community diversity in the field. Phosphorus addition in a bioassay experiment produced a mycorrhizal growth response (MGR) and the mycorrhizal P response (MPR) shifted from positive to negative, regardless of the origin of the inoculum. An increase in intraradical and extraradical AM fungal structures enhanced maize shoot biomass and P uptake under low (no P added) and moderate (20 mg P added kg−1 soil) P levels but the opposite occurred at a high P level (250 mg P added kg−1 soil). The MGR was higher in the treatment with higher community diversity at the moderate P level but there was no significant correlation at the other two P levels examined. We conclude that available soil P may regulate the abundance and diversity of AM fungi and their symbiotic function in intensive cropping systems. Our results indicate that managing the soil phosphorus level to favor a rich and diverse AM fungal community can enhance crop production and result in a more sustainable agricultural system.

Molecular diversity of arbuscular mycorrhizal fungal communities across the gradient of alkaline Fe ore tailings, revegetated waste rock to natural soil sites.

Arbuscular mycorrhizal (AM) fungi are important to the establishment of native vegetation for mined land rehabilitation, particularly in semi-arid and infertile landscapes. However, the information has been scarce about the colonization of AM fungal community in alkaline magnetite Fe ore tailing sites (without toxic metal (loid) contamination). The present study has characterized the diversity of AM fungi across typical domains of a magnetite Fe ore mine located in 200km south-east of Geraldton, Western Australia, by adopting high throughput Illumina Miseq sequencing. The investigated domains included two tailing sites without top soil covering (T1 and T2), a rehabilitated area of tailings with top soil covering (R1), a revegetated waste rock area (R2), and two native undisturbed soil sites (S1 and S2). The results indicated that the T1/T2 sites had different AM fungal community structure, compared with R1/R2 and S1/S2 sites. The dominant families were Glomeraceae, Claroideoglomeraceae, Archaeosporaceae, Ambisporaceae, and Paraglomeraceae, with Paraglomeraceae (more than 50%) as the most abundant in the T1/T2 and R1/R2 sites. At genus level, Ambispora spp. and Archaeospora spp. were rich in T1/T2 sites (> 10%), while Glomus spp. were preferably dominant in S1/S2 sites (> 10%). Furthermore, amorphous Fe and available P were found to explain the variations associated with AM fungal community composition, particularly the abundance of Archaeosporaceae and Glomeraceae. The study revealed the AM fungal community composition shift across the gradient of Fe ore mine sites, as well as the effects of revegetation on AM fungal community development. The findings indicate the possible restoration of AM fungal community in the tailings undergoing revegetation, and potential adoption of indigenous AM fungi to rapid phytostabilization of the Fe ore tailings under semi-arid climatic conditions.