scholarly journals ATP-Dependent but Proton Gradient-Independent Polyphosphate-Synthesizing Activity in Extraradical Hyphae of an Arbuscular Mycorrhizal Fungus

2009 ◽  
Vol 75 (22) ◽  
pp. 7044-7050 ◽  
Author(s):  
Chiharu Tani ◽  
Ryo Ohtomo ◽  
Mitsuru Osaki ◽  
Yukari Kuga ◽  
Tatsuhiro Ezawa
Keyword(s):  
Gradient Centrifugation ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Arbuscular Mycorrhizas ◽  
Compartment System ◽  
Extraradical Hyphae ◽  
System A ◽  
Highly Sensitive ◽  
Mesh Bag

ABSTRACT Arbuscular mycorrhizal (AM) fungi benefit their host plants by supplying phosphate obtained from the soil. Polyphosphate is thought to act as the key intermediate in this process, but little is currently understood about how polyphosphate is synthesized or translocated within arbuscular mycorrhizas. Glomus sp. strain HR1 was grown with marigold in a mesh bag compartment system, and extraradical hyphae were harvested and fractionated by density gradient centrifugation. Using this approach, three distinct layers were obtained: layers 1 and 2 were composed of amorphous and membranous materials, together with mitochondria, lipid bodies, and electron-opaque bodies, and layer 3 was composed mainly of partially broken hyphae and fragmented cell walls. The polyphosphate kinase/luciferase system, a highly sensitive polyphosphate detection method, enabled the detection of polyphosphate-synthesizing activity in layer 2 in the presence of ATP. This activity was inhibited by vanadate but not by bafilomycin A1 or a protonophore, suggesting that ATP may not energize the reaction through H+-ATPase but may act as a direct substrate in the reaction. This report represents the first demonstration that AM fungi possess polyphosphate-synthesizing activity that is localized in the organelle fraction and not in the cytosol or at the plasma membrane.

Frequent cultivation prior to planting to prevent weed competition results in an opportunity for the use of arbuscular mycorrhizal fungus inoculum

2011 ◽  
Vol 27 (4) ◽  
pp. 251-255 ◽  
Author(s):  
David D. Douds ◽  
Gerald Nagahashi ◽  
John E. Shenk
Keyword(s):  
Management Practices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Indigenous Populations ◽  
Paspalum Notatum ◽  
Allium Porrum ◽  
Potential Yield ◽  
Greenhouse Production ◽  
Synthetic Chemicals

AbstractInoculation with arbuscular mycorrhizal (AM) fungi is a potentially useful tool in agricultural systems with limited options regarding use of synthetic chemicals for fertility and pest control. We tested the response ofAllium porrumcv. Lancelot to inoculation with AM fungi in a field high in available P (169 μg g−1soil) that had been repeatedly cultivated to control weeds. Seedlings were inoculated during the greenhouse production period with a mixed species inoculum produced on-farm in a compost and vermiculite medium withPaspalum notatumFlugge as a nurse host. Inoculated and uninoculated seedlings were the same size at outplanting. Inoculated seedlings were over 2.5-fold greater in shoot weight and shoot P content than uninoculated seedlings at harvest. These results demonstrate the potential yield benefits from inoculation with AM fungi in situations where farm management practices may negatively impact on indigenous populations of AM fungi.

scholarly journals Ectomycorrhizas accelerate decomposition to a greater extent than arbuscular mycorrhizas in a northern deciduous forest

2021 ◽  
Author(s):  
Alexis Carteron ◽  
Fabien Cichonski ◽  
Etienne Laliberté
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Deciduous Forest ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Arbuscular Mycorrhizas ◽  
Fungal Hyphae ◽  
Organic Horizons ◽  
Temperate Deciduous ◽  
Temperate Deciduous Forests

AbstractIt has been proposed that ectomycorrhizal (EcM) fungi slow down decomposition by competing with free-living saprotrophs for organic nutrients and other soil resources (known as the “Gadgil effect”), thereby increasing soil carbon sequestration. As such, this Gadgil effect should depend on soil organic matter age and quality, but this remains unstudied. In addition, the Gadgil effect is not expected to occur in arbuscular mycorrhizal (AM) forests since AM fungi cannot access directly nutrients from soil organic matter, yet few direct comparisons between EcM and AM forests have been made. We performed a two-year reciprocal decomposition experiment of soil organic horizons (litter - L, fragmented - F, humic - H) in adjacent temperate deciduous forests dominated by EcM or AM trees. Litterbags were made of different mesh sizes allowing or excluding ingrowth of external fungal hyphae, which are primarily mycorrhizal in these forests other than for the most-recent superficial litter horizon. As expected, organic matter originating from deeper horizons and from EcM forests was of lower quality (e.g. higher lignin to nitrogen ratios) and decomposed more slowly. However, contrary to the Gadgil effect, organic matter exposed to external fungal hyphae (i.e. primarily mycorrhizal) actually decomposed faster in both forest types, and this effect was strongest in EcM forests, particularly in the F horizon. Unexpectedly, organic matter decomposition was faster in EcM than in AM forests, regardless of organic matter origin. Overall, our study reinforces the view that temperate EcM forests store greater amounts of soil organic carbon than AM forests, but suggests that this is due to factors other than the Gadgil effect.

Impact of an arbuscular mycorrhizal fungus on the growth and nutrition of fifteen crop and pasture plant species

2019 ◽  
Vol 46 (8) ◽  
pp. 732 ◽  
Author(s):  
Binh T. T. Tran ◽  
Stephanie J. Watts-Williams ◽  
Timothy R. Cavagnaro
Keyword(s):  
Plant Species ◽  
Mycorrhizal Fungus ◽  
Agricultural Practices ◽  
Arbuscular Mycorrhizal ◽  
Growth Conditions ◽  
Arbuscular Mycorrhizas ◽  
Allium Ampeloprasum ◽  
Mycorrhizal Colonisation ◽  
Pasture Plant ◽  
Diverse Plant Species

The formation of arbuscular mycorrhizas (AM) can result in positive, neutral or negative responses in the growth and mineral nutrition of host plants, particularly that of P, Zn and other micronutrients. This study examined the growth and nutritional responses of 15 agriculturally important plant species, including cereals, legumes and vegetables, with and without inoculation with the AM fungus (AMF) Rhizophagus irregularis. Furthermore, we explored whether the responses differed between different functional groups of plants such as monocots and dicots, C3 and C4 plants, and N-fixing and non-N-fixing plants. We found that that mycorrhizal colonisation of roots, plant growth and plant nutrient responses differed between plant species. Among the species analysed, leek (Allium ampeloprasum L. var. porrum) was the most mycorrhiza-responsive, displaying the highest mycorrhizal colonisation and biomass response, and the greatest increases in most mineral nutrients. In other plant species, the concentration of P, Cu, Zn and S were generally enhanced by inoculation with AMF. Furthermore, ionomes differed more greatly between plant species than in response to inoculation with AMF. This research further improves our understanding of the responses of different and diverse plant species to the formation of AM in terms of growth and ionomics under standardised growth conditions. The results of this study may be used in further studies and to inform agricultural practices.

scholarly journals Diversity of Arbuscular Mycorrhizal Fungus Populations in Heavy-Metal-Contaminated Soils

1999 ◽  
Vol 65 (2) ◽  
pp. 718-723 ◽  
Author(s):  
C. Del Val ◽  
J. M. Barea ◽  
C. Azcón-Aguilar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Agricultural Soils ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Wiener Index ◽  
Life Cycles ◽  
The European Union

ABSTRACT High concentrations of heavy metals have been shown to adversely affect the size, diversity, and activity of microbial populations in soil. The aim of this work was to determine how the diversity of arbuscular mycorrhizal (AM) fungi is affected by the addition of sewage-amended sludge containing heavy metals in a long-term experiment. Due to the reduced number of indigenous AM fungal (AMF) propagules in the experimental soils, several host plants with different life cycles were used to multiply indigenous fungi. Six AMF ecotypes were found in the experimental soils, showing consistent differences with regard to their tolerance to the presence of heavy metals. AMF ecotypes ranged from very sensitive to the presence of metals to relatively tolerant to high rates of heavy metals in soil. Total AMF spore numbers decreased with increasing amounts of heavy metals in the soil. However, species richness and diversity as measured by the Shannon-Wiener index increased in soils receiving intermediate rates of sludge contamination but decreased in soils receiving the highest rate of heavy-metal-contaminated sludge. Relative densities of most AMF species were also significantly influenced by soil treatments. Host plant species exerted a selective influence on AMF population size and diversity. We conclude based on the results of this study that size and diversity of AMF populations were modified in metal-polluted soils, even in those with metal concentrations that were below the upper limits accepted by the European Union for agricultural soils.

On-farm production and utilization of arbuscular mycorrhizal fungus inoculum

2005 ◽  
Vol 85 (1) ◽  
pp. 15-21 ◽  
Author(s):  
D. D. Douds Jr. ◽  
G. Nagahashi ◽  
P. E. Pfeffer ◽  
W. M. Kayser ◽  
C. Reider
Keyword(s):  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Plant Production ◽  
Growth And Yield ◽  
Farm Production ◽  
Technological Barriers ◽  
Potential Benefits ◽  
Potting Media ◽  
On Farm

Arbuscular mycorrhizal (AM) fungi colonize the roots of the majority of crop plants, forming a symbiosis that potentially enhances nutrient uptake, pest resistance, water relations, and soil aggregation. Inoculation with effective isolates of AM fungi is one way of ensuring the potential benefits of the symbiosis for plant production. Although inocula are available commercially, on-farm production of AM fungus inoculum would save farmers the associated processing and shipping costs. In addition, farmers could produce locally adapted isolates and generate a taxonomically diverse inoculum. On-farm inoculum production methods entail increasing inoculated isolates or indigenous AM fungi in fumigated or unfumigated field soil, respectively, or transplanting pre-colonized host plants into compost-based substrates. Subsequent delivery of the inoculum with seed to the planting hole in the field presents technological barriers that make these methods more viable in labor-intensive small farms. However, a readily available method for utilization of these inocula is mixing them into potting media for growth of vegetable seedlings for transplant to the field. Direct application of these inocula to the field and transplant of seedlings precolonized by these inocula have resulted in enhanced crop growth and yield. Key words: AM fungi, sustainable agriculture, biofertilizer

scholarly journals Salmonella and Escherichia coli O157:H7 Survival in Soil and Translocation into Leeks (Allium porrum) as Influenced by an Arbuscular Mycorrhizal Fungus (Glomus intraradices)

2013 ◽  
Vol 79 (6) ◽  
pp. 1813-1820 ◽  
Author(s):  
Joshua B. Gurtler ◽  
David D. Douds ◽  
Brian P. Dirks ◽  
Jennifer J. Quinlan ◽  
April M. Nicholson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Allium Porrum ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
E Coli ◽  
The Mean

ABSTRACTA study was conducted to determine the influence of arbuscular mycorrhizal (AM) fungi onSalmonellaand enterohemorrhagicEscherichia coliO157:H7 (EHEC) in autoclaved soil and translocation into leek plants. Six-week-old leek plants (with [Myc+] or without [Myc−] AM fungi) were inoculated with composite suspensions ofSalmonellaor EHEC at ca. 8.2 log CFU/plant into soil. Soil, root, and shoot samples were analyzed for pathogens on days 1, 8, 15, and 22 postinoculation. Initial populations (day 1) were ca. 3.1 and 2.1 log CFU/root, ca. 2.0 and 1.5 log CFU/shoot, and ca. 5.5 and 5.1 CFU/g of soil forSalmonellaand EHEC, respectively. Enrichments indicated that at days 8 and 22, only 31% of root samples were positive for EHEC, versus 73% positive forSalmonella. The meanSalmonellalevel in soil was 3.4 log CFU/g at day 22, while EHEC populations dropped to ≤0.75 log CFU/g by day 15. Overall,Salmonellasurvived in a greater number of shoot, root, and soil samples, compared with the survival of EHEC. EHEC was not present in Myc− shoots after day 8 (0/16 samples positive); however, EHEC persisted in higher numbers (P= 0.05) in Myc+ shoots (4/16 positive) at days 15 and 22.Salmonella, likewise, survived in statistically higher numbers of Myc+ shoot samples (8/8) at day 8, compared with survival in Myc− shoots (i.e., only 4/8). These results suggest that AM fungi may potentially enhance the survival ofE. coliO157:H7 andSalmonellain the stems of growing leek plants.

scholarly journals A review of the interaction of medicinal plants and arbuscular mycorrhizal fungi in the rhizosphere

2021 ◽  
Vol 49 (3) ◽  
pp. 12454
Author(s):  
Rui-Ting SUN ◽  
Ze-Zhi ZHANG ◽  
Nong ZHOU ◽  
A.K. SRIVASTAVA ◽  
Kamil KUČA ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Mycorrhizal Fungi ◽  
Growth Promotion ◽  
Clinical Importance ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Arbuscular Mycorrhizas ◽  
High Concentration ◽  
Clinical Drugs

Medicinal plants are well known to have the advantages of high concentration of medicinal ingredients having clinical importance, curative value, small toxic and side effects. Important compounds viz., paclitaxel, camptothecin, and vincristine have been developed from medicinal plants as first-line of clinical drugs, leading to their consistently increasing demand globally. However, the destruction of natural environment due to excessive mining threatened such resources jeopardizing the successful growing of medicinal plants. A group of beneficial arbuscular mycorrhizal (AM) fungi is known to exist in the rhizosphere of medicinal plants, which can establish a reciprocal symbiosis with their roots, namely arbuscular mycorrhizas. These AM fungi are pivotal in the habitat adaptation of medicinal plants. Studies have demonstrated that AM fungi aided in growth promotion and nutrient absorption of medicinal plants, thereby, accelerating the accumulation of medicinal ingredients and aiding resistance against abiotic stresses such as drought, low temperature, and salinity. An AM-like fungus Piriformospora indica is known to be cultured in vitro without roots, later showed analogous effects of AM fungi on medicinal plants. These fungi provide new mechanistic pathways towards the artificial cultivation of medicinal plants loaded with ingredients in huge demand in international market. This review provides an overview of the diversity of AM fungi inhabiting the rhizosphere of medicinal plants, and analyzes the functioning of AM fungi and P. indica, coupled with future lines of research.

scholarly journals Trait-based aerial dispersal of arbuscular mycorrhizal fungi

2020 ◽  
Author(s):  
V. Bala Chaudhary ◽  
Sarah Nolimal ◽  
Moisés A. Sosa-Hernández ◽  
Cameron Egan ◽  
Jude Kastens
Keyword(s):  
Community Structure ◽  
Mycorrhizal Fungi ◽  
High Throughput Sequencing ◽  
Fungal Spores ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Global Scale ◽  
Arbuscular Mycorrhizas ◽  
List Type ◽  
Aerial Dispersal

SUMMARYDispersal is a key process driving local-scale community assembly and global-scale biogeography of plant symbiotic arbuscular mycorrhizal (AM) fungal communities. A trait-based approach could improve predictions regarding how AM fungal aerial dispersal varies by species.We conducted month-long collections of aerial AM fungi for 12 consecutive months in an urban mesic environment at heights of 20 m. We measured functional traits of all collected spores and assessed aerial AM fungal community structure both morphologically and with high-throughput sequencing.Large numbers of AM fungal spores were present in the air over the course of one year and these spores were more likely to exhibit traits that facilitate dispersal. Aerial spores were smaller than average for Glomeromycotinan fungi. Trait-based predictions indicate that nearly 1/3 of described species from diverse genera demonstrate the potential for aerial dispersal. Diversity of aerial AM fungi was relatively high (20 spore species and 17 virtual taxa) and both spore abundance and community structure shifted temporally.The prevalence of aerial dispersal in arbuscular mycorrhizas is perhaps greater than previously indicated and a hypothesized model of AM fungal dispersal mechanisms is presented. Anthropogenic soil impacts may initiate the dispersal of disturbance-tolerating AM fungal species and facilitate community homogenization.

scholarly journals Asymbiotic mass production of the arbuscular mycorrhizal fungus Rhizophagus clarus

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Sachiko Tanaka ◽  
Kayo Hashimoto ◽  
Yuuki Kobayashi ◽  
Koji Yano ◽  
Taro Maeda ◽  
...  
Keyword(s):  
Life Cycle ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Terrestrial Ecosystems ◽  
Hormonal Control ◽  
Root Colonisation ◽  
Rhizophagus Clarus ◽  
Am Symbiosis ◽  
Fungal Life Cycle

AbstractArbuscular mycorrhizal (AM) symbiosis is a mutually beneficial interaction between fungi and land plants and promotes global phosphate cycling in terrestrial ecosystems. AM fungi are recognised as obligate symbionts that require root colonisation to complete a life cycle involving the production of propagules, asexual spores. Recently, it has been shown that Rhizophagus irregularis can produce infection-competent secondary spores asymbiotically by adding a fatty acid, palmitoleic acid. Furthermore, asymbiotic growth can be supported using myristate as a carbon and energy source for their asymbiotic growth to increase fungal biomass. However, the spore production and the ability of these spores to colonise host roots were still limited compared to the co-culture of the fungus with plant roots. Here we show that a combination of two plant hormones, strigolactone and jasmonate, induces the production of a large number of infection-competent spores in asymbiotic cultures of Rhizophagus clarus HR1 in the presence of myristate and organic nitrogen. Inoculation of asymbiotically-generated spores promoted the growth of host plants, as observed for spores produced by symbiotic culture system. Our findings provide a foundation for the elucidation of hormonal control of the fungal life cycle and the development of inoculum production schemes.

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