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Sample records for vesicular-arbuscular mycorrhizal infection

  1. Effect of vesicular arbuscular mycorrhizal fungus on the ...

    African Journals Online (AJOL)

    The symbiotic association between certain plants and microorganisms plays an important role in soil fertilization, and improves their growth and mineral nutrition. The symbiotic association between vesicular arbuscular mycorrhizal (VAM) fungi and roots provides a significant contribution to plant nutrition and growth.

  2. Vesicular-Arbuscular Mycorrhiza in Field-Grown Crops. I. Mycorrhizal Infection in Cereals and Peas at Various Times and Soil Depths

    DEFF Research Database (Denmark)

    Jakobsen, Iver; Nielsen, N.E.

    1983-01-01

    Development of infection by vesicular-arbuscular mycorrhiza (VAM) was studied in some field-grown crops. An infection plateau was reached within the first month after seedling emergence of spring barley, oats and peas. During the rest of the growth period the proportion of root length infected...

  3. The vesicular-arbuscular mycorrhizal symbiosis | Quilambo | African ...

    African Journals Online (AJOL)

    Vesicular-arbuscular mycorrhiza fungi are associated with the majority ot the terrestrial plants. Their function ranges from stress alleviation to bioremediation in soils polluted with heavy metals. However, our knowledge about this symbiosis is still limited. For the semi-arid tropics, where some african countries are located, ...

  4. Reduction of bacterial growth by a vesicular-arbuscular mycorrhizal fungus in the rhizosphere of cucumber (Cucumis sativus L.)

    DEFF Research Database (Denmark)

    Christensen, H.; Jakobsen, I.

    1993-01-01

    Cucumber was grown in a partially sterilized sand-soil mixture with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum or left uninoculated. Fresh soil extract was places in polyvinyl chloride tubes without propagules of mycorrhizal fungi. Root tips and root segments...

  5. The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover

    Directory of Open Access Journals (Sweden)

    Lin, XG.

    1993-01-01

    Full Text Available Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight of shoots and roots, total uptake of nitrogen, phosphorus and other elements, the final yields and recovery of phosphorus of white clover were significantly increased by vesicular-arbuscular mycorrhizal inoculation and dual inoculation with vesicular-arbuscular mycorrhizal fungi and rhizobium. The highest response of inoculation was obtained by adding fertilizer phosphorus at the level of 60 kg P205 ha in form of superphosphate.

  6. Arbuscules of vesicular-arbuscular mycorrhizal fungi inhabit an acidic compartment within plant roots.

    Science.gov (United States)

    Guttenberger, M

    2000-08-01

    The most widespread type of mycorrhiza is the so-called vesicular-arbuscular mycorrhiza. In this endomycorrhiza, fungal hyphae penetrate plant cell walls in the root cortex. There they form densely branched arbuscules. Fungus and plant plasma membrane are separated by a common interfacial apoplast. The pH of the compartment between the symbionts is of pivotal importance for nutrient transfer. Histochemical experiments were conducted to check for an acidic nature of the interface in the model system Glomus versiforme (Karst.) Berch-Allium porrum L. Two chemically different acidotropic dyes (neutral red and LysoSensor Green DND-189) stained the arbuscules intensely. The staining of arbuscules could be eliminated by addition of the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) or treatments leading to membrane rupture. Therefore, the staining of the arbuscules was based on the ion-trap mechanism, which indicates acidic, membrane-bound compartments. Microscopic examination of stained arbuscules at high optical resolution revealed a peripheral accumulation of the dye. Since plasmolysis rapidly destained the arbuscules, it is concluded that the dyes accumulate in the arbuscular interface, indicating the highly acidic nature of this compartment. The findings are discussed with respect to their relevance for the nutrient transfer in mycorrhizas. In addition, evidence for a discontinuity in the arbuscular interface between the stem and the branches of the arbuscule is given.

  7. Comparison of vesicular-arbuscular mycorrhizae in plants from disturbed and adjacent undisturbed regions of a coastal salt marsh in Clinton, Connecticut, USA

    Science.gov (United States)

    Cooke, John C.; Lefor, Michael W.

    1990-01-01

    Roots of salt marsh plant species Spartina alterniflora, S. patens, Distichlis spicata, and others were examined for the presence of vesicular-arbuscular mycorrhizal (VAM) fungi. Samples were taken from introduced planted material in a salt marsh restoration project and from native material in adjacent marsh areas along the Indian River, Clinton, Connecticut, USA. After ten years the replanted area still has sites devoid of vegetation. The salt marsh plants introduced there were devoid of VAM fungi, while high marsh species from the adjacent undisturbed region showed consistent infection, leading the authors to suggest that VAM fungal infection of planting stocks may be a factor in the success of marsh restoration.

  8. Vesicular-Arbuscular Mycorrhiza in Field-Grown Crops

    DEFF Research Database (Denmark)

    Jakobsen, Iver

    1986-01-01

    The importance of vesicular-arbuscular mycorrhiza (VAM) and P fertilizer for P nutrition and dry matter production in field peas (Pisum sativum L.) was studied in moderately P-deficient soil. Half of the experimental plots were fumigated to reduce the level of VAM infection. Shoots and 0 to 30 cm...... in fumigated plots, although both it and P uptake were increased by adding P fertilizer. The possible reasons for this discrepancy are discussed. A supplementary survey on infection development at five other field sites showed that peas are extensively colonized by VAM fungi, even in soils where a standard...

  9. Laboratory bioassay for assessing the effects of sludge supernatant on plant growth and vesicular-arbuscular mycorrhiza formation

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, K.S.; Liberta, A.E.

    1982-12-01

    A laboratory bioassay is described for assessing the effects of sludge supernatant on juvenile corn growth and the ability of vesicular-arbuscular (VA) mycorrhizal fungi, indigenous to coal spoil, to form mycorrhizae. The bioassay demonstrated that application rates can be identified that have the potential to promote increased plant dry weight without suppressing the formation of VA mycorrhizae in a plant's root system.

  10. Influence of vesicular arbuscular mycorrhiza (VAM) and phosphate ...

    African Journals Online (AJOL)

    A field experiment was carried out to find out the effect of biofertilizers, vesicular arbuscular mycorrhiza (VAM), and phosphate solubilising bacteria (PSB) individually and in combination on growth and physiological attributing properties of Marsdenia volubilis plant under nursery conditions. The plant seedlings were ...

  11. Seasonality of vesicular-arbuscular mycorrhizae in sedges in a semi-arid tropical grassland

    Science.gov (United States)

    Muthukumar, T.; Udaiyan, K.

    2002-10-01

    Vesicular-arbuscular mycorrhizal (VAM) colonization and spore numbers in the rhizosphere of Cyperus iria L. and C. rotundus L., growing in a semi-arid tropical grassland, was studied during the 1993 and 1994 monsoons. In addition, climatic and chemical properties of the soils were determined in order to investigate their influence on mycorrhizal variables. VAM fungal association in the sedges was confirmed by plant- and root-trap culture techniques. The soil nutrients exhibited seasonal variations, but were highly variable between years. Intercellular hyphae and vesicles with occasional intraradical spores characterized mycorrhizal association in sedges. Dark septate fungi also colonized roots of sedges. Temporal variations in mycorrhizal colonization and spore numbers occurred, indicating seasonality. However, the patterns of mycorrhizal colonization and spore numbers were different during both the years. The VAM fungal structures observed were intercellular hyphae and vesicles. Changes in the proportion of root length with VAM structures, total colonization levels and spore numbers were related to climatic and edaphic factors. However, the intensity of influence of climatic and soil factors on VAM tended to vary with sedge species.

  12. The vesicular-arbuscular mycorrhizal symbiosis | Quilambo | African ...

    African Journals Online (AJOL)

    African Journal of Biotechnology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 12 (2003) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  13. Effect of vesicular arbuscular mycorrhizal fungus on the ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-06

    Oct 6, 2008 ... were estimated following the method of Dubois et al. (1956). The amount of nitrate formed was measured by the method of Cataldo et al. (1975). Estimation of praline was done according to Bates. (1973). The dried plant materials were ground in porcelain mortar with porcelain pestle and the N content was ...

  14. Vesicular-arbuscular-/ecto-mycorrhiza succession in seedlings of. Eucalyptus spp.

    Directory of Open Access Journals (Sweden)

    Santos Vera Lúcia dos

    2001-01-01

    Full Text Available The occurrence of vesicular-arbuscular mycorrhizae (AM and ectomycorrhizae (ECM in the same root system was observed when species of Eucalyptus urophylla S.T. Blake, E. citriodora Hook f., E. grandis W. Hill ex Maiden, E. cloeziana F. Muell. and E. camaldulensis Dehnh were simultaneously inoculated with Glomus etunicatum Becker & Gederman and Pisolithus tinctorius (Per. Cocker & Couch, isolate Pt 90A. The succession between the two fungi was observed. In general ectomycorrhizal colonization increased followed by a decrease in AM. Pisolithus tinctorius was favored in simultaneous inoculation with G. etunicatum, and the positive effect of the simultaneous inoculation of both fungi in the percent colonization by the AM fungus occurred up to 60 days after inoculation. After 120 days, colonization of roots by G. etunicatum decreased in the presence of P. tinctorius. When inoculated simultaneously, the proportion of AM and ECM varied with evaluation time, while the combined percentage of mycorrhizal roots approached the maximum and remained more or less constant after 60 days, suggesting that there could be competition between the fungi for limiting substrate. The maximum percent mycorrhizal colonization varied with Eucalyptus species and the highest value was observed for E. camaldulensis, followed in order by E. citriodora, E. urophylla, E. grandis and E. cloeziana.

  15. Effect of solarization and vesicular arbuscular mychorrizal on weed ...

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... determine VAM before testing in laboratory, VAM dutied like a bridge from donor lettuce to receiver wild mustard (Sinapsis ... Also the laboratory findings supported this; the number of spores, number of VAM infected and infection rate ..... Technics and usages of Mycorrhizal spor in agricultura. Cukurova.

  16. Vesicular-arbuscular mycorrhiza response to crossed carbon and phosphorus resource gradients

    Energy Technology Data Exchange (ETDEWEB)

    Whitbeck, J.L. (Pennyslvania State Univ., University Park, PA (United States))

    1994-06-01

    Employing the annual herb Hemizonia luzulaefolia, native to nutrient limited grassland ecosystem in California, and a community of indigenous vesicular-arbuscular mycorrhizal (VAM) fungi, this study examined mycorrhizal response to interacting plant- and fungus-acquired resources. Plant carbon supply was manipulated through atmospheric carbon dioxide (CO[sub 2]) concentration, and substrate phosphorus (P) supply was varied in the nutrient solution. H. luzulaefolia responded strongly to VAM association, showing increased root and shoot biomass, greater leaf area, higher shoot P content and lower specific root length relative to non-mycorrhizal plants. Elevated (700 ppm) CO[sub 2] plants had lower mass, lower root:shoot ratios and slightly greater specific root length than ambient pCO[sub 2]-grown plants. VAM colonization of roots was stimulated by elevated CO[sub 2] early in the experiment. Low P plants showed greater leaf mass per area and lower shoot P concentration than plus-P plants. P effects on measures of VAM changed over time. While ambient pCO[sub 2]-grown plants responsed to added P with increased biomass, plants grown at elevated CO[sub 2] showed equivalent or lower biomass in plus-P treatments than in those with no added P. At the same time, ambient pCO[sub 2]-grown plants developed greater VAM colonization of roots in low P treatments, while at 700 ppm CO[sub 2]. VAM colonization was higher in plus-P treatments. It appears that atmospheric pCO[sub 2] affects the patterns of belowground allocation in H. luzulaefolia: ambient pCO[sub 2] plants direct carbon resources to VAM when P is low and to roots when P is available, while elevated CO[sub 2] plants maintain VAM colonization regardless of P environment and allocate to roots when P is low.

  17. Factors influencing survival of vesicular-arbuscular mycorrhiza propagules during topsoil storage

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.M.; Carnes, B.A.; Moorman, T.B.

    1985-01-01

    The survival dynamics of vesicular-arbuscular mycorrhizal fungi were determined, (using a bioassay procedure) for soils stored from 0.5 to 6.0 years in topsoil stockpiles associated with a coal surface-mine in the western United States. Propagule mortality could best be related to in situ soil moisture potential using a piecewise regression model (R/sup 2/ = 0.57; P less than or equal to 0.001) with the breaking point occurring at -2 MPa. The addition of length of storage time was found to contribute significantly to the accuracy of the model (R/sup 2/ = 0.70; P less than or equal to 0.001). In addition, the piece-wise nature of the data suggested two separate populations of VAM fungi - those propagules found in soils with moisture potentials less than -2 MPa and those occurring in soils with moisture potentials greater than -2 MPa. Soil moisture and length of storage time had differing effects on each of these populations. When water potential was less than -2 MPa, moisture was an important predictor of inoculum (P < 0.001), while length of storage had little predictive capability (P = 0.17). However, when water potentials were greater than -2 MPa, the predictive importance of soil moisture (P = 0.86) and length of storage (P = 0.04) were reversed. The significance of these findings to topsoil replacement and subsequent plant community development are discussed. 28 references, 2 figures, 2 tables.

  18. Survey of vesicular-arbuscular mycorrhizae in lettuce production in relation to management and soil factors

    Science.gov (United States)

    Miller, R.L.; Jackson, L.E.

    1998-01-01

    The occurrence of vesicular-arbuscular mycorrhizae (VAM) root colonization and spore number in soil was assessed for 18 fields under intensive lettuce (Lactuca sativa L.) production in California during July and August of 1995. Data on management practices and soil characteristics were compiled for each field, and included a wide range of conditions. The relationship between these factors and the occurrence of VAM in these fields was explored with multivariate statistical analysis. VAM colonization of lettuce tended to decrease with the use of chemical inputs, such as pesticides and high amounts of P and N fertilizers. Addition of soil organic matter amendments, the occurrence of other host crops in the rotation, and soil carbon:phosphorus and carbon:nitrogen ratios, were positively associated with VAM colonization of lettuce roots. The number of VAM spores in soil was strongly correlated with the number of other host crops in the rotation, the occurrence of weed hosts and sampling date, but was more affected by general soil conditions than by management inputs. Higher total soil N, C and P, as well as CEC, were inversely related to soil spore number. A glasshouse study of the two primary lettuce types sampled in the field showed no significant differences in the extent of root colonization under similar growing conditions. The results of this study are compared with other studies on the effects of management and soil conditions on mycorrhizal occurrence in agriculture.

  19. Effect of endomycorrhizae on interactions between mycorrhizal and nonmycorrhizal plants. [Glomus monosporum/mosseae; Atriplex canescens; Sitanion hystrix

    Energy Technology Data Exchange (ETDEWEB)

    Franson, R.; Miller, R.M.

    1984-01-01

    An investigation on how infection with vesicular-arbuscular mycorrhizal fungi (VAM) changes interactions between plants was initiated. Specifically addressed were how does the presence or absence of VAM affect: (1) a species that typically shows little or no infection; and (2) a species that typically possesses moderate levels of infection. Results show: roots for inoculated species were higher than uninoculated treatments; the above ground dry weight gain were significantly higher with inoculation. The growth response of both species suggests a fungus-to-plant interaction even though infection, as measured by arbuscules a vesicles, was not always present. 2 figures. (MF)

  20. The development and significance of vesicular-arbuscular mycorrhizas as influenced by agricultural practices

    NARCIS (Netherlands)

    Ruissen, M.A.

    1982-01-01

    The development and significance of vesicular- arbuscular mycorrhizas (VAM) in wheat and potatoes have been studied in relation to various farming systems and agricultural practices. The effects of farming systems on VAM have been observed on three neighbouring experimental farms in the vicinity of

  1. The influence of vesicular-arbuscular mycorrhizas on production ...

    African Journals Online (AJOL)

    arbuscular mycorrhizas produced slight increases in dry mater production in unsterilized field plots at Cedara, Natal. Phosphorus levels in plant tops showed no increases due to mycorrhizas but crude protein content of all mycorrhizal plants were ...

  2. Vesicular-Arbuscular Mycorrhiza in Field-Grown Crops

    DEFF Research Database (Denmark)

    Jakobsen, Iver

    1983-01-01

    The effect of inoculation with vesicular–arbuscular mycorrhizal fungi on the growth of barley in the field was studied at two levels of soil P on plots fumigated with methyl bromide. During the vegetative phase, growth and P uptake was influenced only by soil P; P uptake in the period from earing...

  3. Interspecific plant association effects on vesicular-arbuscular mycorrhiza occurrence in Atriplex confertifolia

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.M.; Moorman, T.B.; Schmidt, S.K.

    1983-01-01

    Earlier studies with the shrub Atriplex confertifolia (Chenopodiaceae) suggested that the occurrence of mycotrophy was related to the community from which root samples were obtained; plants in disturbed areas were non-mycotrophic, while those growing in native areas possessed infection. Upon closer examination when neighbouring plants were studied, the level of mycorrhizal infection of Atriplex confertifolia was found to be related to its interspecific plant associations. When Atriplex confertifolia occurred solitarily, or in the presence of non-mycorrhizal A. gardneri, it was non-mycotrophic. However, when occurring near grasses or Artemisia spinescens, it possessed mycorrhiza infection. What appeared to be a community effect for the occurrence of mycorrhiza is nothing more than an association effect in which level of infection is related to the degree of mycorrhizal host plant cover. In disturbed communities little chance occurs for encountering a neighbouring mycorrhizal plant, while native plant communities are composed primarily of mycorrhizal counterparts. 22 references, 1 figure, 3 tables.

  4. Chitinase in roots of mycorrhizal Allium porrum: regulation and localization.

    Science.gov (United States)

    Spanu, P; Boller, T; Ludwig, A; Wiemken, A; Faccio, A; Bonfante-Fasolo, P

    1989-04-01

    Chitinase (EC 3.2.1.14) activity was measured in roots of Allium prorrum L. (leek) during development of a vesicular-arbuscular mycorrhizal symbiosis with Glomus versiforme (Karst.) Berch. During the early stages of infection, between 10 and 20 d after inoculation, the specific activity of chitinase was higher in mycorrhizal roots than in the uninfected controls. However, 60-90 d after inoculation, when the symbiosis was fully established, the mycorrhizal roots contained much less chitinase than control roots. Chitinase was purified from A. porrum roots. An antiserum against beanleaf chitinase was found to cross-react specifically with chitinase in the extracts from non-mycorrhizal and mycorrhizal A. porrum roots. This antiserum was used for the immunocytochemical localization of the enzyme with fluorescent and gold-labelled probes. Chitinase was localized in the vacuoles and in the extracellular spaces of non-mycorrhizal and mycorrhizal roots. There was no immunolabelling on the fungal cell walls in the intercellular or the intracellular phases. It is concluded that the chitin in the fungal walls is inaccessible to plant chitinase. This casts doubts on the possible involvement of this hydrolase in the development of the mycorrhizal fungus. However, fungal penetration does appear to cause a typical defense response in the first stages that is later depressed.

  5. The Effects of Vesicular-Arbuscular Mycorrhizae on the Plant Growth and Nutrient Uptake of Cucumber

    OpenAIRE

    ÇIĞŞAR, Sibel; Sari, Nebahat

    2014-01-01

    This study was conducted to investigate the effect of vesicular-arbuscular (VA) mycorrhizae on plant growth of cucumber. Yayla F 1 seeds were sown in sterile and non-sterile growing medium (organic manure:soil:mix of sand; v:v:v 1:1:1). The mix inoculum of Glomus mosseaand Glomus fasciculatumspores (10 g/plant) was placed 5 cm below the cucumber seed before sowing. In order to investigate the effects of VA mycorrhizae on plant growth, plant height, diameter, number of nodes were measured ...

  6. Effect of solarization and vesicular arbuscular mychorrizal on weed ...

    African Journals Online (AJOL)

    mustard (Sinapsis arvensis L.) as observed in the experiment because mustrad has no symbiosis life with this fungus. Also the laboratory findings supported this; the number of spores, number of VAM infected and infection rate were higher both in main parcel of solarized and in the subplot parcel planted with VAM ...

  7. APPARENT LACK OF VESICULAR-ARBUSCULAR MYCORRHIZA (VAM) IN SEAGRASSES ZOSTERA MARINA L. AND THALASSIA TESTUDIUM BANKS EX KONIG

    Science.gov (United States)

    We examined two populations of Zostera marina L. and one of Thalassia testudinum Banks ex Konig for presence of vesicular-arbuscular mycorrhiza (VAM). None of these plants showed any VAM colonization. In addition, we were unable to find any literature references on the presence o...

  8. Vesicular-Arbuscular Mycorrhiza and Growth in Barley - Effects of Irradiation and Heating of Soil

    DEFF Research Database (Denmark)

    Jakobsen, Iver; Andersen, A. J.

    1982-01-01

    propagules. Mycorrhiza developed more slowly after inoculation in irradiated soils than in untreated soils. This could have been due to the small amounts of inoculum used, but the high concentrations of nutrients released by irradiation of the soil were probably of greater significance particularly......The influence of soil irradiation (0.25–4.0 Mrad) and soil heating on mycorrhizal survival, establishment and development after reinoculation, and on plant growth, was investigated. The lowest radiation dose applied, completely eliminated the infectivity of a soil with a high number of mycorrhizal...

  9. NUTRIENT TRANSFER IN VESICULAR-ARBUSCULAR MYCORRHIZAS: A NEW MODEL BASED ON THE DISTRIBUTION OF ATPases ON FUNGAL AND PLANT MEMBRANES

    Directory of Open Access Journals (Sweden)

    S.E. SMITH

    1995-01-01

    Full Text Available In this paper we review the membrane transport processes that are involved in the transfer of mineral nutrients and organic carbon between the symbiotic partners in mycorrhizas. In particular, we reassess the prevailing hypothesis that transfer in vesicular-arbuscular (VA mycorrhizas occurs simultaneously and bidirectionally across the same interface and that arbuscules are the main sites of transfer. Using cytochemical techniques, we and our collaborators have reexamined the distribution of ATPases in the arbuscular and intercellular hyphal interfaces in VA mycorrhizas formed between roots ofAllium cepa (onion and the fungus Glomus intraradices. The results showed that H +-ATPases have different localisation on plant and fungal membranes in arbuscular and hyphal interfaces (Gianinazzi-Pearson et al. 1991. While some arbuscular interfaces had H+-ATPase activity on both fungal and plant membranes, in most cases the fungal membrane lacked this activity. In contrast, the plasma membranes of intercellular hyphae always had H + -ATPase and the adjacent root cells did not. This suggests that the different interfaces in a VA mycorrhiza may have different functions. We propose that passive loss of P from the arbuscules is associated with active uptake by the energised (ATPase-bearing plant membrane and that passive loss of carbohydrate from the root cells is followed by active uptake by the intercellular hyphae. If this model is correct, then variations in "mycorrhizal efficiency" (i.e. the extent to which mycorrhizal plants grow better than non-mycorrhizal controls might be determined by differences in the numbers of active arbuscules as a proportion of the total fungal biomass within the root. As a first step towards investigating this possibility, we have developed methods for measuring the surface areas of arbuscular and hyphal interfaces in different fungus-host combinations, Glomus spp./ Allium porrum (leek. We have also measured fluxes of P from

  10. Hyphal N transport by a vesicular-arbuscular mycorrhizal fungus associated with cucumber grown at three nitrogen levels

    DEFF Research Database (Denmark)

    Johansen, A.; Jakobsen, I.; Jensen, E.S.

    1994-01-01

    Cucumis sativus L. cv. Aminex (F1 hybrid) was grown alone or in symbiosis with Glomus intraradices Schenck and Smith in containers with two hyphal compartments (HC(A) and HC(B)) on either side of a root compartment (RC) separated by fine nylon mesh. Plants received a total of either 100, 200 or 400...

  11. Hyphal transport by a vesicular-arbuscular mycorrhizal fungus of N applied to the soil as ammonium or nitrate

    DEFF Research Database (Denmark)

    Johansen, A.; Jakobsen, I.; Jensen, E.S.

    1993-01-01

    with a hyphal compartment separated from the root compartment by a fine nylon mesh. Mineral N was then applied to the hyphal compartment as (NH4+)-N-15 or (NO3-)-N-15 at 5 cm distance from the root compartment. Soil samples were taken from the hyphal compartment at 1, 3 and 5 cm distance from the root...

  12. The Role of Teak Leaves (Tectona grandis), Rhizobium, and Vesicular-Arbuscular Mycorrhizae on Improving Soil Structure and Soil Nutrition

    Science.gov (United States)

    Yuliani; Rahayu, Y. S.

    2018-01-01

    Calcium is the largest mineral in calcareous soils. High levels of calcium carbonate lead to phosphate deposition. Nutrient deficiencies in calcareous soil (mainly Phosphate and Nitrogen) resulted only certain crops with a wide range of tolerances that can grow. Meanwhile, dynamics nutrient in calcareous soils also depend on the topography and decomposition of the litter in the growing vegetation. The purpose of this study was to describe the pattern of nutrient enhancement and soil-texture structures on calcareous soils after littering the teak leaves, Rhizobium and Vesicular Arbuscular Mycorrhiza. The research parameters were the concentration of N, P, K; C/N ratio, humid acid content, and soil structure, which measured at days 30, 60, and 85 of soil decomposition process. The results showed that at days 30, the texture and structure of the soil tend to be stable (porosity 31.2, DMR 1.93, moisture content 0.36, sandy clay) while at days 85 has been very stable (porosity 49.8; Water content 0.28, sandy clay). While C and N organic, N and K concentration at days 30 showed low value (C organic 1.03, N 0.12, K 0.49, C / N ratio 9). This condition is almost unchanged at days 85. While the P value shows very high value (60.53) at days 30 although after 60 days the P content showed a decrease.

  13. Growth and Nutrient Uptake Responses of Kinnow to Vesicular Arbuscular Mycorrhizae

    OpenAIRE

    M.H. Shamshiri; K Usha; Bhupinder Singh

    2012-01-01

    In a field experiment, three-year-old Kinnow trees budded on Jatti Katti (C. jambhiri) rootstock were inoculated by three different arbuscular mycorrhiza (AM), Glomus manihotis (T1), Glomus mosseae (T2), and Gigaspora gigantia (T3), separately or in combination (T4). Microscopic assessment of AM colonization on Kinnow roots showed a relatively lower level of infection by different species when inoculated separately than when inoculaed together. Application of AM improved growth parameters lik...

  14. Selection of Infective Arbuscular Mycorrhizal Fungal Isolates for Field Inoculation

    Directory of Open Access Journals (Sweden)

    Elisa Pellegrino

    2010-09-01

    Full Text Available Arbuscular mycorrhizal (AM fungi play a key role in host plant growth and health, nutrient and water uptake, plant community diversity and dynamics. AM fungi differ in their symbiotic performance, which is the result of the interaction of two fungal characters, infectivity and efficiency. Infectivity is the ability of a fungal isolate to establish rapidly an extensive mycorrhizal symbiosis and is correlated with pre-symbiotic steps of fungal life cycle, such as spore germination and hyphal growth. Here, different AM fungal isolates were tested, with the aim of selecting infective endophytes for field inoculation. Greenhouse and microcosm experiments were performed in order to assess the ability of 12 AM fungal isolates to produce spores, colonize host roots and to perform initial steps of symbiosis establishment, such as spore germination and hyphal growth. AM fungal spore production and root colonization were significantly different among AM fungal isolates. Spore and sporocarp densities ranged from 0.8 to 7.4 and from 0.6 to 2.0 per gram of soil, respectively, whereas root colonization ranged from 2.9 to 72.2%. Percentage of spore or sporocarp germination ranged from 5.8 to 53.3% and hyphal length from 4.7 to 79.8 mm. The ordination analysis (Redundancy Analysis, RDA showed that environmental factors explained about 60% of the whole variance and their effect on fungal infectivity variables was significant (P = 0.002. The biplot clearly showed that variables which might be used to detect infective AM fungal isolates were hyphal length and root colonization. Such analysis may allow the detection of the best parameters to select efficient AM fungal isolates to be used in agriculture.

  15. Application of the EDYS Model to Evaluate Control Methods for Invasive Plants at Yakima Training Center, Washington

    Science.gov (United States)

    2004-12-01

    Anderson. 1987. Effects of soil moisture and soil sterilization on vesicular- arbuscular mycorrhizal colonization and growth of little bluestem...potassium, and in the density of mycorrhiza , in biennial and matrix-forming perennial species of closed chalkland turf. Journal of Ecology 70:571-593...nitrogen between pasture plants infected with vesicular- arbuscular mycorrhizal fungi. New Phytologist 108:417-423. Heil, G.W. and W.H. Diemont. 1983

  16. Effect of poplar genotypes on mycorrhizal infection and secreted enzyme activities in mycorrhizal and non-mycorrhizal roots

    Science.gov (United States)

    Courty, P. E.; Labbé, J.; Kohler, A.; Marçais, B.; Bastien, C.; Churin, J. L.; Garbaye, J.; Le Tacon, F.

    2011-01-01

    The impact of ectomycorrhiza formation on the secretion of exoenzymes by the host plant and the symbiont is unknown. Thirty-eight F1 individuals from an interspecific Populus deltoides (Bartr.)×Populus trichocarpa (Torr. & A. Gray) controlled cross were inoculated with the ectomycorrhizal fungus Laccaria bicolor. The colonization of poplar roots by L. bicolor dramatically modified their ability to secrete enzymes involved in organic matter breakdown or organic phosphorus mobilization, such as N-acetylglucosaminidase, β-glucuronidase, cellobiohydrolase, β-glucosidase, β-xylosidase, laccase, and acid phosphatase. The expression of genes coding for laccase, N-acetylglucosaminidase, and acid phosphatase was studied in mycorrhizal and non-mycorrhizal root tips. Depending on the genes, their expression was regulated upon symbiosis development. Moreover, it appears that poplar laccases or phosphatases contribute poorly to ectomycorrhiza metabolic activity. Enzymes secreted by poplar roots were added to or substituted by enzymes secreted by L. bicolor. The enzymatic activities expressed in mycorrhizal roots differed significantly between the two parents, while it did not differ in non-mycorrhizal roots. Significant differences were found between poplar genotypes for all enzymatic activities measured on ectomycorrhizas except for laccases activity. In contrast, no significant differences were found between poplar genotypes for enzymatic activities of non-mycorrhizal root tips except for acid phosphatase activity. The level of enzymes secreted by the ectomycorrhizal root tips is under the genetic control of the host. Moreover, poplar heterosis was expressed through the enzymatic activities of the fungal partner. PMID:20881013

  17. Does ozone exposure alter growth and carbon allocation of mycorrhizal plants

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, L.C.; Gamon, J.A. (California State Univ., Los Angeles, CA (United States)); Andersen, C.P. (Environmental Protection Agency, Corvallis, OR (United States))

    1994-06-01

    Ozone is known to adversely affect plant growth. However, it is less clear how ozone affects belowground processes. This study tests the hypothesis that ozone alters growth and carbon allocation of vesicular arbuscular mycorrhizal (VAM) plants. Two ecotypes of Elymus glaucus (blue wild rye) were exposed to mycorrhizal inoculation and episodic ozone exposures simulating atmospheric conditions in the Los Angeles Basin. Preliminary results show that effects of ozone on growth were subtle. In both ecotypes, growth of aboveground biomass was not affected by ozone while root growth was decreased. In most treatments, mycorrhizal inoculation decreased growth of leaves and stems, but had no significant effect on root growth. Three-way ANOVA tests indicated interactive effects between ecotype, mycorrhiza and ozone. Further experimental work is needed to reveal the biological processes governing these responses.

  18. Structure and function of mycorrhizal fungus communities of the Red Desert

    Energy Technology Data Exchange (ETDEWEB)

    McGraw, A.C.; Miller, R.M.

    1984-01-01

    A chronological study since 1977 in the Red Desert of Wyoming is enabling examination into the sequence of events coupling mycotrophy with revegetation following strip-mining activities. Observational data support the hypothesis that diversification in the plant community and structure is ensured with the establishment of the mycotrophic habit; thereby increasing resiliency of the community for recovery from perturbations. The objectives of this research were: (1) to identify the species of vesicular-arbuscular mycorrhizal fungi (MF) present and evaluate primary edaphic factors affecting the population dynamics of the MF; (2) to isolate native species of MF; and (3) to develop a model system for characterizing stresses such as extremes in moisture and temperature on the coupling and function (particularly the cost-benefit of mycotrophy to the host) of mycorrhizal symbionts. 2 tables.

  19. [Infection Unit Density as an Index of Infection Potential of Arbuscular Mycorrhizal Fungi].

    Science.gov (United States)

    Ohtomo, Ryo; Kobae, Yoshihiro; Morimoto, Sho; Oka, Norikuni

    2018-02-06

    The effective use of arbuscular mycorrhizal (AM) fungal function to promote host plant phosphate uptake in agricultural practice requires the accurate quantitative evaluation of AM fungal infection potential in field soil or AM fungal inoculation material. The number of infection units (IUs), intraradical fungal structures derived from single root entries formed after a short cultivation period, may reflect the number of propagules in soil when pot soil is completely permeated by the host root. However, the original IU method, in which all AM propagules in a pot are counted, requires the fine tuning of plant growing conditions and is considered to be laborious. The objective of the present study was to test whether IU density, not the total count of IU, but the number of IUs per unit root length, reflects the density of AM fungal propagules in soil. IU density assessed after 12 d of host plant cultivation and 3,3'-diaminobenzidine (DAB) staining showed a stronger linear correlation with propagule density than the mean infection percentage (MIP). In addition, IU density was affected less by the host plant species than MIP. We suggest that IU density provides a more rapid and reliable quantitation of the propagule density of AM fungi than MIP or the original IU method. Thus, IU density may be a more robust index of AM fungal infection potential for research and practical applications.

  20. SOURCES OF MYCORRHIZAL INFECTION OF SHOREA ACUMINATA SEEDLINGS UNDER LABORATORY CONDITIONS

    Directory of Open Access Journals (Sweden)

    LEE Su SEE

    1995-01-01

    Full Text Available Uninoculated dipterocarp seedlings raised in normal field soil in nurseries were always found to have mycorrhizas after a few months. This study set out to determine whether dipterocarp seedlings could continue to grow and develop in the absence of mycorrhizas and also to determine possible sources of mycorrhizal infection of dipterocarp seedlings raised under laboratory conditions using Shorea acuminata as a typical example. Seedlings were planted in capped or uncapped perspex boxes containing sterile or non-sterile field soil and watered daily with sterile water or tap water. Seedling growth and development of mycorrhizas were monitored at monthly intervals for up to seven months. Seedlings grown in sterile soil remained uninfected after seven months while infection was found in some of the seedlings grown in normal soil regardless of whether they had been watered with tap water or sterile water. This showed that field soil (i.e. under grass far from the forest contained suitable inoculum for forest tree seedlings. Tap water and the air were not important sources of infection. However, mycorrhizal infection was very uneven indicating that the inoculum was probably very unevenly distributed in the soil or that the inoculum density was rather low. Seedlings grown in sterile soil showed better growth than those grown in normal soil and infection of roots by parasitic fungi in the latter was also observed.

  1. Arbuscular mycorrhizal fungi reduce growth and infect roots of the non-host plant Arabidopsis thaliana.

    Science.gov (United States)

    Veiga, Rita S L; Faccio, Antonella; Genre, Andrea; Pieterse, Corné M J; Bonfante, Paola; van der Heijden, Marcel G A

    2013-11-01

    The arbuscular mycorrhizal (AM) symbiosis is widespread throughout the plant kingdom and important for plant nutrition and ecosystem functioning. Nonetheless, most terrestrial ecosystems also contain a considerable number of non-mycorrhizal plants. The interaction of such non-host plants with AM fungi (AMF) is still poorly understood. Here, in three complementary experiments, we investigated whether the non-mycorrhizal plant Arabidopsis thaliana, the model organism for plant molecular biology and genetics, interacts with AMF. We grew A. thaliana alone or together with a mycorrhizal host species (either Trifolium pratense or Lolium multiflorum) in the presence or absence of the AMF Rhizophagus irregularis. Plants were grown in a dual-compartment system with a hyphal mesh separating roots of A. thaliana from roots of the host species, avoiding direct root competition. The host plants in the system ensured the presence of an active AM fungal network. AM fungal networks caused growth depressions in A. thaliana of more than 50% which were not observed in the absence of host plants. Microscopy analyses revealed that R. irregularis supported by a host plant was capable of infecting A. thaliana root tissues (up to 43% of root length colonized), but no arbuscules were observed. The results reveal high susceptibility of A. thaliana to R. irregularis, suggesting that A. thaliana is a suitable model plant to study non-host/AMF interactions and the biological basis of AM incompatibility. © 2013 John Wiley & Sons Ltd.

  2. BIOFERTILIZATION WITH RHIZOBACTERIA AND A CONSORTIUM OF ARBUSCULAR MYCORRHIZAL FUNGI IN CITRUS ROOTSTOCKS

    Directory of Open Access Journals (Sweden)

    Roberto Gregorio Chiquito-Contreras

    2012-11-01

    Full Text Available Biofertilization of plants with rhizobacteria and vesicular arbuscular mycorrhizae (mycorrhizal consortium, potentially promotes plant growth and health, and reduces the use of agrochemicals. The effect of individual and combined biofertilization with three strains of rhizobacteria and the mycorrhizal consortium (MTZ-1 was evaluated under nursery conditions on the growth of rootstocks of Citrus volkameriana and Rangpur lime grafted with Tahiti lime. Plants were inoculated individually and combined with the rhizobacteria strains FCA-8, FCA-56 and FCA-60 of Pseudomonas putida, and with MTZ-1; 50 % fertilization also was applied (18-46-00 N-P-K and compared with controls that received nursery management and 100 % fertilization. A split-plot experimental design with five replications per treatment was established. Individual and combined biofertilization with the three strains of bacteria and MTZ-1 positively promoted the growth of C. volkameriana, and Rangpur lime grafted with Tahiti lime, similar to the control with 100 % fertilization. The nutrient content of Tahiti lime leaves was similar to the control for both rootstocks. The presence of rhizobacterial and mycorrhizal populations in the combined biofertilization treatments demonstrated a positive synergism in the colonization of rootstock roots. Results demonstrate the potential of the three strains of P. putida and the MTZ-1 mycorrhizal consortium on the promotion of plant growth and assimilation of nutrients.

  3. Antioxidant defenses of mycorrhizal fungus infection against SO(2)-induced oxidative stress in Avena nuda seedlings.

    Science.gov (United States)

    Huang, L L; Yang, C; Zhao, Y; Xu, X; Xu, Q; Li, G Z; Cao, J; Herbert, S J; Hao, L

    2008-11-01

    Colonization of arbuscular mycorrhizal fungi Glomus mosseae increased Avena nuda seedling tolerance to SO(2) exposure, as indicated by elevated total plant biomass and ameliorative photosynthetic rate, when compared to the non-mycorrhizal plants. This is associated with an improved antioxidant capacity as shown by enhanced superoxide dismutase and catalase activity, increased ascorbic acid and glutathione content, and reduced malondialdehyde and hydrogen peroxide level in the mycorrhizal plants relative to the non-mycorrhizal plants under SO(2) exposure. The mycorrhizal fungi colonization had no effect on the stomatal conductance. To our knowledge, this is the first finding of this sort.

  4. Browse Title Index

    African Journals Online (AJOL)

    Items 151 - 200 of 444 ... Vol 24 (1991), Effects of nitrate and ammonium nitrogen on vesicular-arbuscular mycorrhizal infection in letttuce (Lactuca sativa) grown in sand with nutrient solutions, Abstract. E Owusu-Benoah. Vol 20 (1987), Effects of N-nitrate fertilization on yield and dinitrogen fixation in common bean (Phaseolus ...

  5. Author Details

    African Journals Online (AJOL)

    Owusu-Benoah, E. Vol 24 (1991) - Articles Effects of nitrate and ammonium nitrogen on vesicular-arbuscular mycorrhizal infection in letttuce (Lactuca sativa) grown in sand with nutrient solutions. Abstract. ISSN: 0855-0042. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  6. Vesicular-arbuscular mycorrhiza in guayule

    Energy Technology Data Exchange (ETDEWEB)

    Bloss, H.E.

    1980-01-01

    There is renewed interest in the cultivation of guayule (Parthenium argentatum A. Gray) as a domestic source of natural rubber. Guayule roots from Texas were observed for the presence of mycorrihizae. A symbiont identified as Glomus fasciculatus has been isolated. (ACR)

  7. The arbuscular mycorrhizal symbiosis attenuates symptom severity and reduces virus concentration in tomato infected by Tomato yellow leaf curl Sardinia virus (TYLCSV).

    Science.gov (United States)

    Maffei, Giulia; Miozzi, Laura; Fiorilli, Valentina; Novero, Mara; Lanfranco, Luisa; Accotto, Gian Paolo

    2014-04-01

    The arbuscular mycorrhizal (AM) symbiosis is considered a natural instrument to improve plant health and productivity since mycorrhizal plants often show higher tolerance to abiotic and biotic stresses. However, the impact of the AM symbiosis on infection by viral pathogens is still largely uncertain and little explored. In the present study, tomato plants were grown under controlled conditions and inoculated with the AM fungus Funneliformis mosseae. Once the mycorrhizal colonization had developed, plants were inoculated with the Tomato yellow leaf curl Sardinia virus (TYLCSV), a geminivirus causing one of the most serious viral diseases of tomatoes in Mediterranean areas. Biological conditions consisted of control plants (C), TYLCSV-infected plants (V), mycorrhizal plants (M), and TYLCSV-infected mycorrhizal plants (MV). At the time of analysis, the level of mycorrhiza development and the expression profiles of mycorrhiza-responsive selected genes were not significantly modified by virus infection, thus indicating that the AM symbiosis was unaffected by the presence and spread of the virus. Viral symptoms were milder, and both shoot and root concentrations of viral DNA were lower in MV plants than in V plants. Overall F. mosseae colonization appears to exert a beneficial effect on tomato plants in attenuating the disease caused by TYLCSV.

  8. Changes in the anatomy, morphology and mycorrhizal infection of fine root systems of Cryptomeria japonica in relation to stand ageing.

    Science.gov (United States)

    Hishi, Takuo; Tateno, Ryunosuke; Fukushima, Keitaro; Fujimaki, Reiji; Itoh, Masami; Tokuchi, Naoko; Näsholm, Torgny

    2017-01-31

    Biomass allocation to fine roots often increases under soil nutrient deficiency, but the fine root biomass does not often increase in old stands, even under nutrient limitation. Therefore, in old stands, the morphology, anatomy, branching architecture and mycorrhization of fine roots may compensate efficiently for nutrient acquisition by the low fine root biomass. In this study, changes in the morphology, anatomy and arbuscular mycorrhizal infection at each branching position of fine root clusters were evaluated in relation to stand age. A chronosequence (6–90 years of age) of stands in a Cryptomeria japonica D. Don plantation was used for these analyses. The fine root size parameters, such as length, weight and tip numbers of fine root clusters, increased with stand age. The specific root tip length (SRTL) decreased with increasing stand age, suggesting that the allocation to root active portions decreased with stand age. From the anatomical observation, the ephemeral root tips increased with stand age, suggesting that root tip turnover within a root cluster was high in old stands. The proportions of proto-xylem groups among branching positions indicated that the life cycles in branching hierarchy should be clearer in old stands than that in younger stands. The increasing in the mycorrhizal infection of root tips in old stands should enhance the root tip absorptive functions. The SRTL was correlated with the wood/needle ratio, suggesting that carbon limitation as the stand ages may result in decline of carbon allocation to maintain active root tips. However, increasing of the ephemeral tips and mycorrhizal infection rates may compensate the declines of tip allocation in old stands.

  9. Predicting infectivity of Arbuscular Mycorrhizal fungi from soil variables using Generalized Additive Models and Generalized Linear Models

    Directory of Open Access Journals (Sweden)

    IRNANDA AIKO FIFI DJUUNA

    2010-07-01

    Full Text Available Djuuna IAF, Abbott LK, Van Niel K (2010 Predicting infectivity of Arbuscular Mycorrhizal fungi from soil variables using Generalized Additive Models and Generalized Linear Models. Biodiversitas 11: 145-150. The objective of this study was to predict the infectivity of arbuscular mycorrhizal fungi (AM fungi, from field soil based on soil properties and land use history using generalized additive models (GAMs and generalized linear models (GLMs. A total of 291 soil samples from a farm in Western Australia near Wickepin were collected and used in this study. Nine soil properties, including elevation, pH, EC, total C, total N, P, K, microbial biomass carbon, and soil texture, and land use history of the farm were used as independent variables, while the percentage of root length colonized (%RLC was used as the dependent variable. GAMs parameterized for the percent of root length colonized suggested skewed quadratic responses to soil pH and microbial biomass carbon; cubic responses to elevation and soil K; and linear responses to soil P, EC and total C. The strength of the relationship between percent root length colonized by AM fungi and environmental variables showed that only elevation, total C and microbial biomass carbon had strong relationships. In general, GAMs and GLMs models confirmed the strong relationship between infectivity of AM fungi (assessed in a glasshouse bioassay for soil collected in summer prior to the first rain of the season and soil properties.

  10. Carbon cost of the fungal symbiont relative to net leaf P accumulation in a split-root VA mycorrhizal symbiosis. [Poncirus trifoliata L. Raf. x Citrus sinensis L. Osbeck; Glomus intraradices Schenk and Smith

    Energy Technology Data Exchange (ETDEWEB)

    Douds, D.D. Jr.; Johnson, C.R.; Koch, K.E. (Univ. of Florida, Gainesville (USA))

    1988-02-01

    Translocation of {sup 14}C-photosynthates to mycorrhizal (++), half mycorrhizal (0+), and nonmycorrhizal (00) split-root systems was compared to P accumulation in leaves of the host plant. Carrizo citrange seedlings (Poncirus trifoliata (L.) Raf. {times} Citrus sinensis (L.) Osbeck) were inoculated with the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith. Plants were exposed to {sup 14}CO{sub 2} for 10 minutes and ambient air for 2 hours. Three to 4% of recently labeled photosynthate was allocated to metabolism of the mycorrhiza in each inoculated root half independent of shoot P concentration, growth response, and whether one or both root halves were colonized. Nonmycorrhizal roots respired more of the label translocated to them than did mycorrhizal roots. Label recovered in the potting medium due to exudation or transport into extraradical hyphae was 5 to 6 times greater for (++) versus (00) plants. In low nutrient media, roots of (0+) and (++) plants transported more P to leaves per root weight than roots of (00) plants. However, when C translocated to roots utilized for respiration, exudation, etc., as well as growth is considered, (00) plant roots were at least as efficient at P uptake (benefit) per C utilized (cost) as (0+) and (++) plants. Root systems of (++) plants did not supply more P to leaves than (0+) plants in higher nutrient media, yet they still allocated twice the {sup 14}C-photosynthate to the mycorrhiza as did (0+) root systems.

  11. Functional analysis of duplicated Symbiosis Receptor Kinase (SymRK) genes during nodulation and mycorrhizal infection in soybean (Glycine max).

    Science.gov (United States)

    Indrasumunar, Arief; Wilde, Julia; Hayashi, Satomi; Li, Dongxue; Gresshoff, Peter M

    2015-03-15

    Association between legumes and rhizobia results in the formation of root nodules, where symbiotic nitrogen fixation occurs. The early stages of this association involve a complex of signalling events between the host and microsymbiont. Several genes dealing with early signal transduction have been cloned, and one of them encodes the leucine-rich repeat (LRR) receptor kinase (SymRK; also termed NORK). The Symbiosis Receptor Kinase gene is required by legumes to establish a root endosymbiosis with Rhizobium bacteria as well as mycorrhizal fungi. Using degenerate primer and BAC sequencing, we cloned duplicated SymRK homeologues in soybean called GmSymRKα and GmSymRKβ. These duplicated genes have high similarity of nucleotide (96%) and amino acid sequence (95%). Sequence analysis predicted a malectin-like domain within the extracellular domain of both genes. Several putative cis-acting elements were found in promoter regions of GmSymRKα and GmSymRKβ, suggesting a participation in lateral root development, cell division and peribacteroid membrane formation. The mutant of SymRK genes is not available in soybean; therefore, to know the functions of these genes, RNA interference (RNAi) of these duplicated genes was performed. For this purpose, RNAi construct of each gene was generated and introduced into the soybean genome by Agrobacterium rhizogenes-mediated hairy root transformation. RNAi of GmSymRKβ gene resulted in an increased reduction of nodulation and mycorrhizal infection than RNAi of GmSymRKα, suggesting it has the major activity of the duplicated gene pair. The results from the important crop legume soybean confirm the joint phenotypic action of GmSymRK genes in both mycorrhizal and rhizobial infection seen in model legumes. Copyright © 2015 Elsevier GmbH. All rights reserved.

  12. Differential benefits of arbuscular mycorrhizal and ectomycorrhizal infection of salix repens

    NARCIS (Netherlands)

    Heijden, van der E.W.

    2001-01-01

    The functional significance of arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) for Salix repens, a dual mycorrhizal plant, was investigated over three harvest periods (12, 20 and 30 weeks). Cuttings of S. repens were collected in December (low shoot P) and March (high shoot P). Glomus mosseae

  13. Arbuscular mycorrhizal fungi reduce growth and infect roots of the non-host plant Arabidopsis thaliana

    NARCIS (Netherlands)

    Veiga, R.S.L.; Faccio, A.; Genre, A.; Pieterse, C.M.J.; Bonfante, P.; Van der Heijden, M.G.A.

    2013-01-01

    The arbuscular mycorrhizal (AM) symbiosis is widespread throughout the plant kingdom and important for plant nutrition and ecosystem functioning. Nonetheless, most terrestrial ecosystems also contain a considerable number of nonmycorrhizal plants. The interaction of such non-host plants with AM

  14. Effect of mycorrhizal infection on root uptake by pine seedlings and redistribution of three contrasting radio-isotopes: {sup 85}Sr, {sup 95m}Tc and {sup 137}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Plassard, C.; Ladeyn, I.; Staunton, S. [Institut National de Recherches Agronomiques (INRA), UMR Rhizosphere and Symbiose 34 - Montpellier (France)

    2004-07-01

    Mycorrhizal infection is known to improve phosphate nutrition and water supply of higher plants. It has been reported to both increase the uptake of potentially toxic pollutant elements and to protect plants against toxic effects. Little is known about the effect of mycorrhizal infection on the dynamics of radioactive pollutants in soil-plant systems. The aim of this study was to compare the root uptake and root-shoot transfer of three radio-isotopes with contrasting chemical properties ({sup 85}Sr, {sup 95m}Tc and {sup 137}Cs) in mycorrhizal and control, non mycorrhizal plants. The plant studied was Pinus pinaster and the associated ecto-mycorrhizal fungus was Rhizopogon roseolus (strain R18-2). Plants were grown under anoxic conditions for 3 months then transferred to thin layers of autoclaved soil and allowed to grow for four months. After this period, the rhizotrons were dismantled, and plant tissue analysed. Biomass, nutrient content (K, P, N, Ca) and activities of each isotope in roots, shoots and stems were measured, and the degree of mycorrhizal infection assessed. The transfer factors decreased in the order Tc>Sr>Cs as expected from the degree of immobilisation by soil. No effect of mycorrhizal infection on root uptake was observed for Sr. Shoot activity concentration of Tc was decreased by mycorrhizal infection but root uptake correlated well with mycelial soil surface area. In contrast, Cs shoot activity was greater in mycorrhizal than control plants. The uptake and root to shoot distribution shall be discussed in relation to nutrient dynamics. (author)

  15. The arbuscular mycorrhizal symbiosis promotes the systemic induction of regulatory defence-related genes in rice leaves and confers resistance to pathogen infection.

    Science.gov (United States)

    Campos-Soriano, Lidia; García-Martínez, José; San Segundo, Blanca

    2012-08-01

    Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. Their association benefits the host plant by improving nutrition, mainly phosphorus nutrition, and by providing increased capability to cope with adverse conditions. In this study, we investigated the transcriptional changes triggered in rice leaves as a result of AM symbiosis, focusing on the relevance of the plant defence response. We showed that root colonization by the AM fungus Glomus intraradices is accompanied by the systemic induction of genes that play a regulatory role in the host defence response, such as OsNPR1, OsAP2, OsEREBP and OsJAmyb. Genes involved in signal transduction processes (OsDUF26 and OsMPK6) and genes that function in calcium-mediated signalling processes (OsCBP, OsCaM and OsCML4) are also up-regulated in leaves of mycorrhizal rice plants in the absence of pathogen infection. In addition, the mycorrhizal rice plants exhibit a stronger induction of defence marker genes [i.e. pathogenesis-related (PR) genes] in their leaves in response to infection by the blast fungus Magnaporthe oryzae. Evidence indicates that mycorrhizal rice plants show enhanced resistance to the rice blast fungus. Overall, these results suggest that the protective effect of the AM symbiosis in rice plants relies on both the systemic activation of defence regulatory genes in the absence of pathogen challenge and the priming for stronger expression of defence effector genes during pathogen infection. The possible mechanisms involved in the mycorrhiza-induced resistance to M. oryzae infection are discussed. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

  16. United States Air Force Summer Faculty Research Program for 1990. Program Management Report

    Science.gov (United States)

    1991-06-05

    Laboratory 144 An Assay to Determine the Phytotoxic Effects Dr. David Buckalew of Jet Fuel: Effects on Vesicular- Arbuscular Mycorrhizae 114 Volume IV...Fuel: Effects on Vesicular- Arbuscular Mycorrhizae by David W. Buckalew ABSTRACT A new protocol is presented for using plants as analytical tools to...measures of total root length and percent vesicular- arbuscular mycorrhizal colonization are recorded within a common test grass. A brief discussion of

  17. The roles of arbuscular mycorrhizal fungi in the intensity of the foot rot disease on pepper plant from the infected soil

    Directory of Open Access Journals (Sweden)

    Norma Fauziyah

    2017-07-01

    Full Text Available Pepper (Piper nigrum L. is an important spice plant of  Indonesia. In Bangka Belitung Province, the main pepper producer, pepper has been the most commonly cultivated commodity. However, the production has declined from time to time. One of the causes of the decline is Pepper Fot Rot, caused by Phytophthora capsici. The rapid spread and development of the disease is mainly due to utilization of diseased plant materials for pepper cuttings and infested or diseased plantation soil. The materials used in this research included the infected soil taken from the infectedpepper plantation at Bangka Island with disease intensity of pepper foot rot 60%, inoculum of Arbuscular Mycorrhizal fungi in the zeolite medium, compost, and pepper seedling from Natar variety. This research was done by planting pepper seedling on infected soil and observing plant height, disease intensity, and infection of AM fungi on the roots. The results showed that soil from diseased pepper plants harbored high population of plant pathogens inoculum and caused the death of 9 week-old cuttings and retarded growth of the survivors. Sterilization of the infected soil with hot water vapor for 3 hours still could not control the pathogen. Good growth was observed on one node cutting planted in sterile soil amended with arbuscular mycorrhizal fungi.

  18. Influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on development and efficacy of vesicular-arbuscular mycorrhiza in tropical and subtropical plants. Einfluss von Al und den Schwermetallen Fe, Mn, Zn, Cu, Pb und Cd auf die Effizienz der VA-Mykorrhiza bei tropischen und subtropischen Pflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Fabig, B.

    1982-07-08

    In greenhouse experiments the influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on the efficacy of VA-mycorrhizal fungi was tested with special regard to several soil pH levels and soil water regimes in different combinations. The most important results were: The inoculation led to a significantly better growth of all test plants in the presence of Al, Fe, Mn, Zn, Cu, Pb, and Cd up to a specific amount of the soil-applied element; beyond this specific limit the efficacy of the mycorrhiza was more or less inhibited depending on the element. In correlation with the growth, the nearly always better P uptake of the inoculated plants was impaired only by the highest toxic amounts of the elements. In comparison with the uninoculated plants, all the inoculated plants showed higher P and Pb concentrations. The mycorrhizal plants generally had significantly higher concentrations of the elements Al, Mn, Zn, Cu, and Cd in the roots than the uninoculated plants. Generally even toxic levels of Fe in the soil did not lead to higher Fe concentrations in the plants. Even the highest amounts of Al, Fe, Mn, Zn, and Cu did not cause microscopically visible injuries to the development of the mycorrhiza and did not impede the infection. Only the toxic levels of Pb led to a decrease of the infection rate of about 50%. Pb and Cd were the reason for morphological changes of the different developmental phases of the fungus. High amounts of Pb induced an increased formation of vesicles. The highest amounts of Cd were accompanied by the crowded occurrence of arbuscules.

  19. Influence of vesicular arbuscular mycorrhiza (VAM) and phosphate ...

    African Journals Online (AJOL)

    User

    2013-09-18

    Sep 18, 2013 ... Organic wastes and biofertilizers are alternate sour- ... consequence of regular application of chemical fertilizers. However, a large proportion of soluble inorganic phos- phate added to soil is rapidly fixed as insoluble forms.

  20. Effect of solarization and vesicular arbuscular mychorrizal on weed ...

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... To determine VAM before testing in laboratory, VAM dutied like a bridge from donor lettuce to receiver wild mustard (Sinapsis arvensis L.) as observed in the experiment because mustrad has no symbiosis life with this fungus. Also the laboratory findings supported this; the number of spores, number of VAM.

  1. Evidence of differences between the communities of arbuscular mycorrhizal fungi colonizing galls and roots of Prunus persica infected by the root-knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Alguacil, Maria del Mar; Torrecillas, Emma; Lozano, Zenaida; Roldán, Antonio

    2011-12-01

    Arbuscular mycorrhizal fungi (AMF) play important roles as plant protection agents, reducing or suppressing nematode colonization. However, it has never been investigated whether the galls produced in roots by nematode infection are colonized by AMF. This study tested whether galls produced by Meloidogyne incognita infection in Prunus persica roots are colonized by AMF. We also determined the changes in AMF composition and biodiversity mediated by infection with this root-knot nematode. DNA from galls and roots of plants infected by M. incognita and from roots of noninfected plants was extracted, amplified, cloned, and sequenced using AMF-specific primers. Phylogenetic analysis using the small-subunit (SSU) ribosomal DNA (rDNA) data set revealed 22 different AMF sequence types (17 Glomus sequence types, 3 Paraglomus sequence types, 1 Scutellospora sequence type, and 1 Acaulospora sequence type). The highest AMF diversity was found in uninfected roots, followed by infected roots and galls. This study indicates that the galls produced in P. persica roots due to infection with M. incognita were colonized extensively by a community of AMF, belonging to the families Paraglomeraceae and Glomeraceae, that was different from the community detected in roots. Although the function of the AMF in the galls is still unknown, we hypothesize that they act as protection agents against opportunistic pathogens.

  2. Fungos micorrízicos vesículo-arbusculares em rizosferas de plantas em dunas do Parque Estadual da Ilha do Cardoso, São Paulo, Brasil: (1 Taxonomia Vesicular-arbuscular mycorrhizal fungi from rhizospheres of dunes plants of Parque Estadual da Ilha do Cardoso, São Paulo State, Brazil (1: taxonomy

    Directory of Open Access Journals (Sweden)

    S. F. B Trufem

    1989-01-01

    Full Text Available De março/1988 a março/1989, mensalmente, foram coletadas o total de 450 amostras de solo de rizosferas de plantas de dunas do Parque Estadual da Ilha do Cardoso, Estado de Sáo Paulo, com a finalidade de se verificar a ocorrência de fungos micorrízicos vesículo-arbusculares (MVA. As plantas mais constantemente investigadas foram: Baccharis trimera DC. (Compositae, Blutaparon portulacoides (St. Hü. Mears (Amaranthaceae, Dalbergia hecastaphylla (L. Taub. (Legurninosae, Hydrocotyle bonariensis Lam. (Umbelliferae,Ipomoeapes-caprae (L.Sweet(Convolvulaceae, Polygaid cyparisseas St. Hül & Moq. (Polygalaceae, além de gramíneas, ciperáceas e outras, que foram coletadas mais esporadicamente. O solo foi tratado pela técnica de decantação e peneiramento em via úmida. Foram verificados 14 taxons de fungos MVA: Acaulospora scrobiculata Trappe, Acaulospora tuberculata Janos & Trappe, Cigaspora gigantea (Nicol. & Gerd. Gerd. & Trappe, Glomus fasciculatum (Thaxter Gerd. & Trappe emend. Walker & Koske, Glomus globiferum Koske & Walker, Glomus monosporum Gerd. & Trappe, Sclerocystis sinuosa Gerd. & Bakshi, Scutellospora calospora (Nicol & Gerd Walker & Sanders, Scutellospora coralloidea (Trappe, Gerd. & Ho (Walker & Sanders, Scutellospora gilmorei (Trappe & Gerd. Walker & Sanders, Scutellospora gregaria (Schenck & Nicol. Walker & Sanders, Scutellospora pérsica (Koske & Walker Walker & Sanders, Scutellospora verrucosa Koske & Walker Walker & Sanders e Scutellospora sp. São apresentadas descrições taxonómicas, comentarios e murônimos dos taxons verificados.Monthly, from March/1988 to March/1989 were collected the total of 450 soil samples from rhizospheres of plants from dunes of Parque Estadual da Ilha do Cardoso, São Paulo State, Brazil, to report the occurrence of VANÍ fungus. The investigated plants were: Baccharis trímera DC. (Compositae, Blutaparon portulacoides (St. Hil. Mears (Amaranthaceae, Dalbergia hecastaphylla (L. Taub. (Legumiosae, Hydrocotyle bonariensis Lam. (Umbelliferae, Ipomoea pes-caprae (L. Sweet (Convolvulaceae, Polygala cyparisseas St. Hill & Moq. (Polygalaceae; Gramineae, Cyperaceae and other plants were occasionaly collected. The soil was prepared according the wet sieving and decanting technique. It was observed the following 14 taxa of VA M fungüs: Acaulospora scrobiculata Trappe, Acaulospora tuberculata Janos & Trappe, Gigaspora gigantea (Nicol. & Gerd Gerd & Trappe, Glomus fasciculatum (Thaxter Gerd. & Trappe emend. Walker & Koske, Glomus globiferum Koske & Walker, Glomus monosporum Gerd. & Trappe, Sclerocystís sinuosa Gerd. & Bakshi, Scutellospora calospora (Nicol. & Gerd. Walker & Sanders, Scutellospora collaroidea (Trappe, Gerd. & Ho Walker & Sanders, Scutellospora gilmorei (Trappe & Gerd. Walker & Sanders, Scutellospora gregaria (Schénck & Nicol. Walker & Sanders, Scutellospora pérsica (Koske & Walker Walker & Sanders, Scutellospora verrucosa (Koske & Walker Walker & Sanders and Scutellospora sp. Are presented taxonomical, coments and muronyms of the studied taxa.

  3. Mycorrhizal association of some agroforestry tree species in two ...

    African Journals Online (AJOL)

    Mycorrhizal colonization of different agroforestry tree species in two social forestry nurseries was investigated. Percentage of Arbuscular mycorrhizal (AM) infection, number of resting spores and AM fungi species varies both in tree species as well as in two different nurseries. This variation is attributed to various factors such ...

  4. Arbuscular mycorrhizal symbiosis stimulates key genes of the phenylpropanoid biosynthesis and stilbenoid production in grapevine leaves in response to downy mildew and grey mould infection.

    Science.gov (United States)

    Bruisson, Sébastien; Maillot, Pascale; Schellenbaum, Paul; Walter, Bernard; Gindro, Katia; Deglène-Benbrahim, Laurence

    2016-11-01

    Grapevine (Vitis spp) is susceptible to serious fungal diseases usually controlled by chemical treatments. Arbuscular mycorrhizal fungi (AMF) are obligate plant symbionts which can stimulate plant defences. We investigated the effect of mycorrhization on grapevine stilbenoid defences. Vitis vinifera cvs Chasselas, Pinot noir and the interspecific hybrid Divico, on the rootstock 41B, were mycorrhized with Rhizophagus irregularis before leaf infection by Plasmopara viticola or Botrytis cinerea. Gene expression analysis showed an up-regulation of PAL, STS, and ROMT, involved in the stilbenoid biosynthesis pathway, in plant leaves, 48 h after pathogen inoculation. This defense response could be potentiated under AMF colonization, with an intensity level depending on the gene, the plant cultivar and/or the pathogen. We also showed that higher amounts of active forms of stilbenoids (i.e trans-form of resveratrol, ε- and δ-viniferins and pterostilbene) were produced in mycorrhized plants of the three genotypes in comparison with non-mycorrhized ones, 10 days post-inoculation with either pathogen. These results support the hypothesis that AMF root colonization enhances defence reactions against a biotrophic and a necrotrophic pathogen, in the aerial parts of grapevine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Plant mycorrhizal traits and carbon fates from plot to globe

    Science.gov (United States)

    Soudzilovskaia, N.; Cornelissen, H. H. C.

    2016-12-01

    Evidence is accumulating that plant traits related to mycorrhizal symbiosis, i.e. mycorrhizal type and the degree of plant root colonization by mycorrhizal fungi have important consequences for carbon pools and allocation in plants and soil. How plant and soil carbon pools vary among vegetation dominated by plants of different mycorrhizal types is a new and exciting research challenge. Absence of global databases on abundance of mycorrhizal fungi in soil and plant roots retards research aimed to understand involvement of mycorrhizas into soil carbon transformation processes. Using own data and published studies we have assembled currently world-largest database of plant species-per-site degrees root colonization by two most common types of mycorrhizal fungi, arbuscular mycorrhizal (AM) and ectomycorrhizal (EM). The database features records for plant root colonization degrees by AM and EM (above 8000 records in total). Using this database, we demonstrate that the degree of mycorrhizal fungal colonization has globally consistent patterns across plant species. This suggests that the level of plant species-specific root colonization can be used as a plant trait. I will discuss how combining plot-level field data, literature data and mycorrhizal infection trait data may help us to quantify the carbon consequences of relative dominance by arbuscular versus ectomycorrhizal symbiosis in vegetation from plot to global scale. To exemplify this method, I will present an assessment of the impacts of EM shrub encroachment on carbon stocks in sub-arctic tundra, and show how the plant trait data (root, leaf, stem and mycorrhizal colonization traits) could predict (1) impacts of AM and EM vegetation on soil carbon budget and (2) changes in soil carbon budget due to increase of EM plants in an AM-dominated ecosystem and visa versa. This approach may help to predict how global change-mediated vegetation shifts, via mycorrhizal carbon pools and dynamics, may affect terrestric and

  6. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization

    OpenAIRE

    Amitava Rakshit; Pratapbhanu S Bhadoria

    2010-01-01

    The effect of vesicular arbuscular mycorrhizal (VAM) infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid) were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O) was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P) were higher than in mycorrhized plants without added P or non-mycorrhized plants with...

  7. Does origin of mycorrhizal fungus on mycorrhizal plant influence effectiveness of the mycorrhizal symbiosis?

    NARCIS (Netherlands)

    Heijden, van der E.W.; Kuyper, T.W.

    2001-01-01

    Mycorrhizal effectiveness depends on the compatibility between fungus and plant. Therefore, genetic variation in plant and fungal species affect the effectiveness of the symbiosis. The importance of mycorrhizal plant and mycorrhizal fungus origin was investigated in two experiments. In the first

  8. Enhanced Tomato Disease Resistance Primed by Arbuscular Mycorrhizal Fungus

    Directory of Open Access Journals (Sweden)

    Yuanyuan eSong

    2015-09-01

    Full Text Available Roots of most terrestrial plants form symbiotic associations (mycorrhiza with soil- borne arbuscular mycorrhizal fungi (AMF. Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill. early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL and lipoxygenase (LOX in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related (PR proteins, PR1, PR2 and PR3, as well as defense-related genes LOX, AOC and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT plant, a jasmonate (JA biosynthesis mutant (spr2, and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for

  9. [Effect of five fungicides on growth of Glycyrrhiza uralensis and efficiency of mycorrhizal symbiosis].

    Science.gov (United States)

    Li, Peng-ying; Yang, Guang; Zhou, Xiu-teng; Zhou, Liane-yun; Shao, Ai-juan; Chen, Mei-lan

    2015-12-01

    In order to obtain the fungicides with minimal impact on efficiency of mycorrhizal symbiosis, the effect of five fungicides including polyoxins, jinggangmycins, thiophanate methylate, chlorothalonil and carbendazim on the growth of medicinal plant and efficiency of mycorrhizal symbiosis were studied. Pot cultured Glycyrrhiza uralensis was treated with different fungicides with the concentration that commonly used in the field. 60 d after treated with fungicides, infection rate, infection density, biomass indexes, photosyn- thetic index and the content of active component were measured. Experimental results showed that carbendazim had the strongest inhibition on mycorrhizal symbiosis effect. Carbendazim significantly inhibited the mycorrhizal infection rate, significantly suppressed the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. Polyoxins showed the lowest inhibiting affection. Polyoxins had no significant effect on mycorrhizal infection rate, the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. The other three fungicides also had an inhibitory effect on efficiency of mycorrhizal symbiosis, and the inhibition degrees were all between polyoxins's and carbendazim's. The author considered that fungicide's inhibition degree on mycorrhizal effect might be related with the species of fungicides, so the author suggested that the farmer should try to choose bio-fungicides like polyoxins.

  10. Mycorrhizal association of some agroforestry tree species in two ...

    African Journals Online (AJOL)

    Administrator

    2011-05-05

    May 5, 2011 ... Mycorrhizal colonization of different agroforestry tree species in two social forestry nurseries was investigated. Percentage of Arbuscular ... collected from two social forestry nurseries of Mahabubnagar district (A.P), and brought to the .... main regression line is shown in red. Spores of the lower infection ...

  11. Effect of mycorrhizal inoculum and urea fertilizer on diseases ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-18

    Aug 18, 2008 ... Diseases (rosette virus disease (RVD), Cercospora leaf spot (CLS) and poverty of soils in nutrients are ... Healthy plants infected plants. Figure 1. Effect of mycorrhizae and urea fertilizer on nodulation of groundnut crops 7 weeks after inoculation. .... between mycorrhizal fungi and the plants results in the.

  12. Expanding Genomics of Mycorrhizal Symbiosis

    Directory of Open Access Journals (Sweden)

    Alan eKuo

    2014-11-01

    Full Text Available The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant and soil health, and carbon and nutrient cycles. The symbiosis evolved repeatedly and independently as multiple morphological types (e.g. arbuscular [AM], ectomycorrhizal [ECM] in multiple fungal clades (e.g. phyla Glomeromycota, Ascomycota, Basidiomycota. The accessibility and culturability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first 3 mycorrhizal fungal genomes, representing 3 fungal phyla and 2 mycorrhizal types. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolve through loss of plant-degrading enzymes (PDEs and expansion of lineage-specific gene families, including short secreted protein (SSP effectors and other symbiosis genes. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of gene families in contrast to Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other 2 fungi, the symbiosis can involve similar solutions as loss of PDEs and mycorrhiza-induced SSPs. The mycorrhizal community is building on these studies with 3 large-scale initiatives. The Mycorrhizal Genomics Initiative (MGI is sequencing 35 genomes of multiple fungal clades and mycorrhizal types for phylogenomic and population analyses. 17 MGI species whose symbiosis is reconstitutable in vitro are targeted for comprehensive transcriptomics of mycorrhiza formation. MGI genomes are seeding a set of 50+ reference fungal genomes for annotating metatranscriptomes sampled from 7 diverse well-described soil sites. These 3 projects address fundamental questions about the nature and role of a

  13. Role of the arbuscular mycorrhizal symbiosis in tolerance response against Armillaria mellea in lavender

    Energy Technology Data Exchange (ETDEWEB)

    Calvet, C.; Garcia-Figueres, F.; Lovato, P.; Camprubi, A.

    2015-07-01

    Lavender species form the arbuscular mycorrhizal symbiosis and are at the same time highly susceptible to white root rot. In an attempt to evaluate the response of mycorrhizal Lavandula angustifolia L. to Armillaria mellea (Vahl:Fr) P. Kumm in a greenhouse experiment, plants were previously inoculated with an isolate of the arbuscular mycorrhizal fungus Rhizophagus irregularis (former Glomus intraradices BEG 72) and the influence of the pH growing medium on the plant-symbiont-pathogen interaction was tested in gnotobiotic autotrophic growth systems in which mycorrhizal inoculum was obtained from root organ cultures. After ten months growth dual-inoculated lavender plants grown in containers with a pasteurized substrate mixture produced a similar number of spikes than healthy plants and achieved equivalent plant diameter coverage. When the growing medium in the autotrophic systems was supplemented with calcium carbonate, the inoculation of lavender plantlets with R. irregularis at higher pH (7.0 and 8.5) media caused a significant decrease of A. mellea presence in plant roots, as detected by qPCR. Moreover, the observation of internal root mycorrhizal infection showed that the extent of mycorrhizal colonization increasedin plant rootsgrown at higher pH, indicating that tolerance to white root rot in lavender plants inoculated with R. irregularis could be associated to mycorrhizal establishment. (Author)

  14. Role of the arbuscular mycorrhizal symbiosis in tolerance response against Armillaria mellea in lavender

    Directory of Open Access Journals (Sweden)

    Cinta Calvet

    2015-09-01

    Full Text Available Lavender species form the arbuscular mycorrhizal symbiosis and are at the same time highly susceptible to white root rot. In an attempt to evaluate the response of mycorrhizal Lavandula angustifolia L. to Armillaria mellea (Vahl:Fr P. Kumm in a greenhouse experiment, plants were previously inoculated with an isolate of the arbuscular mycorrhizal fungus Rhizophagus irregularis (former Glomus intraradices BEG 72 and the influence of the pH growing medium on the plant-symbiont-pathogen interaction was tested in gnotobiotic autotrophic growth systems in which mycorrhizal inoculum was obtained from root organ cultures. After ten months growth dual-inoculated lavender plants grown in containers with a pasteurized substrate mixture produced a similar number of spikes than healthy plants and achieved equivalent plant diameter coverage. When the growing medium in the autotrophic systems was supplemented with calcium carbonate, the inoculation of lavender plantlets with R. irregularis at higher pH (7.0 and 8.5 media caused a significant decrease of A. mellea presence in plant roots, as detected by qPCR. Moreover, the observation of internal root mycorrhizal infection showed that the extent of mycorrhizal colonization increasedin plant rootsgrown at higher pH, indicating that tolerance to white root rot in lavender plants inoculated with R. irregularis could be associated to mycorrhizal establishment.

  15. Vesicular-arbuscular mycorrhizae established with Glomus fasciculatus spores isolated from the feces of cricetine mice

    Science.gov (United States)

    Frederick M. Rothwell; Coleman Holt

    1978-01-01

    Cricetine mice were trapped on two revegetated surface-mined areas - one with a freshly seeded grass-legume cover and one with an early successional grass-forb cover. Chlamydospores of Glomus fasciculatus isolated from the feces of these animals produced representative endomycorrhizae with corn under greenhouse conditions.

  16. EFFECTS OF CORN CULTIVAR-TILLAGE SYSTEM COMBINATION ON VESICULAR ARBUSCULAR MYCORRHIZAE

    Directory of Open Access Journals (Sweden)

    Joko Prasetyo .

    2011-10-01

    Full Text Available Pengaruh kombinasi  varietas jagung dan sistem olah tanah terhadap mikorisa vesikular arbuskular.  Penelitian telah dilakukan untuk mengevaluasi pengaruh kombinasi sistem olah tanah dan varietas terhadap  populasi mikorisa vesikular arbuskular. Penelitian juga ditujukan untuk mengetahui pengaruh kombinasi varietas jagung dan sistem olah tanah terhadap infeksi mikorisa vesicular arbuskular. Penelitian terdiri atas enam perlakuan yang disusun dalam rancangan acak kelompok. Perlakuan tersebut adalah varietas RR yang ditanam pada sistem olah tanah konservasi  (RRCT, varietas C7 yang ditanam pada sistem olah tanah konservasi (C7CT, varietas Bisma ditanam pada sistem olah tanah konservasi (BCT, varietas RR ditanam pada sistem olah tanah sempurna (RRFT, varietas C7 yang ditanam pada sistem olah tanah sempurna (C7FT, dan varietas Bisma ditanam pada sistem olah tanah sempurna (BFT. Hasil penelitian pada sistem olah tanah konservasi  menunjukkan bahwa varietas RR dan C7 secara nyata dapat menurunkan infeksi mikorisa dibandingkan dengan varietas Bisma. Hasil penelitian juga menunjukkan bahwa pada varietas RR dan C7, olah tanah konservasi secara nyata menurunkan infeksi mikorisa dibandingkan dengan sistem olah tanah sempurna.

  17. Increasing Growth and Yield of Upland Rice by Application of Vesicular Arbuscular Mycorrhizae and Potassium Fertilizer

    Directory of Open Access Journals (Sweden)

    Dedi Natawijaya

    2012-01-01

    Full Text Available Field experiment with a split plot design has been carried out in order to assess the growth characteristics andyields, and effectiveness of MVA upland rice which were given potassium fertilizer in two growing seasons. MVAinoculation consisted of three treatments (without MVA, Glomus sp. and Gigaspora sp. while potassium fertilizerconsisted of five levels (0, 12.5, 25, 37.5, and 50 kg ha-1 K. The results showed that plant growth variable which wasinoculated by MVA at any levels of K fertilizer was higher in the dry season than that in the wet season, whereas theopposite occurred for net assimilation rate. Potassium content of leaf tissue, shoot/root ratio, and grain weight perhill was determined and mutually dependent on genus MVA, dosages of K fertilizer, and growing season. Harvestindex and grain dry weight per hill were influenced by the growing season and the genus MVA but the effect did notdepend on each other. At all dosages of K fertilizer and any MVA genera, Gigaspora sp. inoculation was better thanthat of Glomus sp. Dry weight of grains per hill was affected by the contribution of grain content per hill, weight of1000 grains and number of productive seedlings per hill. The optimum dosage of K fertilizer in the dry season was32.4 kg ha-1 K with grain yield 3.12 Mg ha-1 for inoculation of Gigaspora sp., whereas the optimum dosage in the wetseason was 34.2 kg ha-1 K for the treatment Glomus sp. inoculation with Gigaspora sp. in the wet season did notreach dosages of optimum K fertilizer.

  18. Effects of vesicular-arbuscular mycorrhizae and seed source on nursery-grown black walnut seedlings

    Science.gov (United States)

    B. L. Brookshire; H. E. Garrett; T. L. Robison

    2003-01-01

    A nursery study was established in Missouri to evaluate the effects of endomycorrhizal inoculation and seed source on the growth of black walnut seedlings. Inoculation, in general, resulted in seedlings with significantly larger sturdiness quotients. Glomus intraradicies was found to produce larger seedlings than Glomus etunicatus...

  19. Mycorrhizal fungi suppress aggressive Agricultural weeds.

    NARCIS (Netherlands)

    Rinaudo, V.; Barberi, P.; Giovannetti, M.; van der Heijden, M.G.A.

    2010-01-01

    Plant growth responses to arbuscular mycorrhizal fungi (AMF) are highly variable, ranging from mutualism in a wide range of plants, to antagonism in some non-mycorrhizal plant species and plants characteristic of disturbed environments. Many agricultural weeds are non mycorrhizal or originate from

  20. Three-way interactions among mutualistic mycorrhizal fungi, plants, and plant enemies: hypotheses and synthesis.

    Science.gov (United States)

    Bennett, Alison E; Alers-Garcia, Janice; Bever, James D

    2006-02-01

    A number of studies have shown that an association with mycorrhizal fungi can alter the outcome of interactions between plants and their enemies. While the directions of these effects vary, their strength suggests the need for greater attention to multispecies interactions among plant enemies, plants, and mycorrhizal fungi. We recognize that mycorrhizal fungi could effect plant enemies by improving plant nutrition, modifying plant tolerance, or modifying plant defenses. In addition, mycorrhizal fungi could directly interfere with pathogen infection, herbivory, or parasitism by occupying root space. We formalize these alternative outcomes of multispecies interactions and explore the long-term dynamics of the plant-enemy interactions based on these different scenarios using a general model of interactions between plants and plant enemies. We then review the literature in terms of the assumptions of the alternative mechanisms and the predictions of these models. Through this effort, we identify new directions in the study of tritrophic interactions between enemies, plants, and soil mutualists.

  1. Effect of management practices on mycorrhizal infection, growth and dry matter partitioning in field-grown bean Efeito de práticas culturais sobre a infecção micorrízica, crescimento e partição da matéria seca de feijão-vagem

    Directory of Open Access Journals (Sweden)

    Antonio Alberto Rocha Oliveira

    1999-07-01

    Full Text Available The experiment was carried out on unsterilized field soil with low phosphorus availability with the objective of examining the effect of cultural practices on mycorrhizal colonization and growth of common bean. The treatments were: three pre-crops (maize, wheat and fallow followed by three soil management practices ("ploughing", mulching and bare fallow without "ploughing" during the winter months. After the cultural practices, Phaseolus vulgaris cv. Canadian Wonder was grown in this soil. Fallowing and soil disturbance reduced natural soil infectivity. Mycorrhizal infection of the bean roots occurred more rapidly in the recently cropped soil than in the fallow soil. Prior cropping with a strongly mycorrhizal plant (maize increased infectivity even further.O experimento foi realizado em solo não-esterilizado com baixo teor de fósforo. Os tratamentos foram: três pré-cultivos (milho, trigo e solo nu, seguidos por três manejos do solo (distúrbio mecânico do solo, cobertura morta e solo nu sem distúrbio no inverno. No ano seguinte à aplicação dos tratamentos, a área experimental foi semeada com Phaseolus vulgaris cv. Canadian Wonder. Os tratamentos com solo nu e o submetido a distúrbio mecânico exibiram as menores densidades de esporos de fungos micorrízicos e reduzida infecção radicular do feijoeiro. A infecção micorrízica foi maior nas parcelas anteriormente cultivadas com cereais, especialmente no pré-cultivo com milho.

  2. When do arbuscular mycorrhizal fungi protect plant roots from pathogens?

    OpenAIRE

    Benjamin A. Sikes

    2010-01-01

    Arbuscular mycorrhizal (AM) fungi are mainly thought to facilitate phosphorus uptake in plants, but they can also perform several other functions that are equally beneficial. Our recent study sheds light on the factors determining one such function, enhanced plant protection from root pathogens. Root infection by the fungal pathogen Fusarium oxysporum was determined by both plant susceptibility and the ability of an AM fungal partner to suppress the pathogen. The non-susceptible plant species...

  3. [Effects of arbuscular mycorrhizal fungi on plant growth and osmotic adjustment matter content of trifoliate orange seedling under water stress].

    Science.gov (United States)

    Wu, Qiang-Sheng; Xia, Ren-Xue

    2004-10-01

    The effects of arbuscular mycorrhizal fungi Glomus mosseae on plant growth and osmotic adjustment matter content of trifoliate orange [Poncirus trifoliata (L.) Raf.] seedlings under water stress were studied in potted culture. The results showed that arbuscular mycorrhizal fungi inoculation could increase plant growth, such as plant height, stem diameter, leaf area, shoot dry weight, root dry weight and plant dry weight, when the water content of soil was 20%, 16% and 12%. Arbuscular mycorrhizal fungi inoculation also promoted active absorbing areas of plant root and absorption of P from plant rhizosphere, enhanced the accumulated quantities of soluble sugar content in leaves and roots, and reduced proline content of leaf. Plant inoculated with arbuscular mycorrhiza had higher plant water use efficiency than non-mycorrhizal plants. Drought tolerance of trifoliate orange seedling inoculated with arbuscular mycorrhiza was enhanced. Effects of arbuscular mycorrhizal fungi inoculation on trifoliate orange seedling under 20% and 16% water content of soil were more significant than under 12% water content of soil. Arbuscular mycorrhizal fungi infection was severely restrained by 12% water content of soil. Thus, effects of arbuscular mycorrhizal fungi on plant probably positively related to the arbuscular mycorrhizal inoculated percentage.

  4. Arbuscular mycorrhizal fungi in terms of symbiosis-parasitism continuum.

    Science.gov (United States)

    Schmidt, B; Gaşpar, S; Camen, D; Ciobanu, I; Sumălan, R

    2011-01-01

    Arbuscular mycorrhizal fungi are forming the most wide-spread mycorrhizal relationships on Earth. Mycorrhiza contributes to phosphorous acquisition, water absorption and resistance to diseases. The fungus promotes the absorption of nutrients and water from soil, meanwhile the host plant offers photosynthetic assimilates in exchange, like carbohydrates, as energy source. The plant benefits from the contribution of symbiotic partner only when nutrients are in low concentrations in soil and the root system would not be able to absorb sufficiently the minerals. When the help of mycorrhizal fungi is not necessarily needed, the host plant is making an economy of energy, suppressing the development of fungi in the internal radicular space. In this moment, the nature of relationship turns from symbiotic to parasitic, triggering a series of defensive reactions from the plant. Also, there were several cases reported when the presence of arbuscular mycorrhizal fungi negatively influenced the host plant. For example, in adverse environmental conditions, like very high temperatures, instead of determining a higher plant biomass and flowering, the mycorrhiza reduces the growth of the host plant. We conducted a pot experiment with hydroponic culture to examine the effect of arbuscular mycorrhiza on development of French marigold as a host plant. As experimental variants, the phosphorous content in nutrient medium and temperature varied. Plants were artificially infected with arbuscular mycorrhizal fungi using a commercial inoculum containing three fungal species, as following: Glomus intraradices, Glomus etunicatum and Glomus claroideum. Colonization intensity and arbuscular richness were checked using root staining with aniline blue and estimation with the Trouvelot method. To observe the differences between plants from the experimental variants, we examined the number of side shoots, flower buds and fully developed flowers, fresh biomass and total leaf area. Results show that

  5. Expanding genomics of mycorrhizal symbiosis.

    Science.gov (United States)

    Kuo, Alan; Kohler, Annegret; Martin, Francis M; Grigoriev, Igor V

    2014-01-01

    The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant nutrition, soil health, and carbon cycling. The symbiosis evolved repeatedly and independently as multiple morphotypes [e.g., arbuscular mycorrhizae (AM), ectomycorrhizal (ECM)] in multiple fungal clades (e.g., phyla Glomeromycota, Ascomycota, Basidiomycota). The accessibility and cultivability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first three mycorrhizal fungal genomes, representing two morphotypes and three phyla. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolve through loss of plant cell wall-degrading enzymes (PCWDEs) and expansion of lineage-specific gene families such as short secreted protein (SSP) effectors. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of families as in Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other two fungi, symbiosis can involve similar solutions as symbiosis-induced SSPs and loss of PCWDEs. The three genomes provide a solid base for addressing fundamental questions about the nature and role of a vital mutualism.

  6. Diversity and Plant Growth Promoting Properties of Rhizobacteria ...

    African Journals Online (AJOL)

    characteristics of plant growth promoting rhizobacteria (PGPR) and hence selected for further study. The sixty six isolates were further ... microorganisms as inoculum to boost production of the crop could be one of the potential ... vesicular arbuscular mycorrhizal (VAM) fungi (Glomus fasiculatum) on mineral content of tef.

  7. Browse Title Index

    African Journals Online (AJOL)

    Items 3951 - 4000 of 11090 ... Vol 10, No 36 (2011), Effect of vermicompost on manifestation of pesticide action on growth of Zinnia elegans, Abstract PDF. AK Sharan, M Kumar, R Singh, AK Neha, GD Sharma, C Jee. Vol 7, No 19 (2008), Effect of vesicular arbuscular mycorrhizal fungus on the physiological and biochemical ...

  8. Root hydraulic conductivity and xylem sap levels of zeatin riboside and abscisic acid in ectomycorrhizal Douglas fir seedlings

    Science.gov (United States)

    Mark D. Coleman; Caroline S. Bledsoe; Barbara A. Smit

    1990-01-01

    Mechanistic hypotheses to explain mycorrhizal enhancement of root hydraulic conductivity (Lp) suggest that phosphorus (P) nutrition, plant growth substances and/or altered morphology may be responsible. Such ideas are based on work with VA (vesicular-arbuscular) mycorrhizas. Since VA mycorrhizas and ectomycorrhizas differ in many respects, they...

  9. Effect of manganese on endomycorrhizal sugar maple seedlings

    Science.gov (United States)

    George A. Schier; Carolyn J. McQuattie

    2002-01-01

    Manganese (Mn) toxicity may play an important role in the poor survival of seedlings in declining sugar maple (Acer saccharum Marsh.) stands in northern Pennsylvania. To determine the effect of Mn on the growth of sugar maple seedlings, 1-year-old seedlings inoculated with vesicular-arbuscular mycorrhizal (VAM) fungi and growing in sand-vermiculite-...

  10. (VAM) and phosphate solubilizing bacteria (PSB)

    African Journals Online (AJOL)

    User

    2013-09-18

    Sep 18, 2013 ... potash mobilizing and plant promoting microorganisms. Vesicular arbuscular mycorrhizal (VAM) fungi improve plant growth through phosphorous nutrition. In addition to phosphorous, they also help in the uptake of other nutri- ent elements. Nutrient absorption by fungal symbionts is due to external hyphae ...

  11. Mid-Infrared and near-infrared spectral properties of mycorrhizal and non-mycorrhizal root cultures.

    Science.gov (United States)

    Calderón, Francisco J; Acosta-Martinez, Veronica; Douds, David D; Reeves, James B; Vigil, Merle F

    2009-05-01

    We investigated the Fourier-transformed mid-infrared (MIR) and near-infrared (NIR) spectroscopic properties of mycorrhizal (M) and non-mycorrhizal (NM) carrot roots with the goal of finding infrared markers for colonization by arbuscular mycorrhizal (AM) fungi. The roots were cultured with or without the AM fungus Glomus intraradices under laboratory conditions. A total of 50 M and NM samples were produced after pooling subsamples. The roots were dried, ground, and scanned separately for the NIR and MIR analyses. The root samples were analyzed for fatty acid composition in order to confirm mycorrhizal infection and to determine the presence of fatty acid markers. Besides the roots, fatty acid standards, pure cultures of saprophytic fungi, and chitin were also scanned in order to identify spectral bands likely to be found in M samples. Principal components analysis (PCA) was used to illustrate spectral differences between the M and NM root samples. The NIR analysis achieved good resolution with the raw spectral data and no pretreatment was needed to obtain good resolution in the PCA analysis of the NIR data. Standard normal variate and detrending pretreatment improved the resolution between M and NM in the MIR range. The PCA loadings and/or the spectral subtraction of selected samples showed that M roots are characterized by absorbances at or close to 400 cm(-1), 1100-1170 cm(-1), 1690 cm(-1), 2928 cm(-1), and 5032 cm(-1). The NM samples had characteristic absorbances at or near 1734 cm(-1), 3500 cm(-1), 4000 cm(-1), 4389 cm(-1), and 4730 cm(-1). Some of the bands that differentiate M from NM roots are prominent in the spectra of pure fungal cultures, chitin, and fatty acids. Our results show that mycorrhizal and nonmycorrhizal root tissues can be differentiated via MIR and NIR spectra with the advantage that the same samples can then be used for other analyses.

  12. Interplant Communication of Tomato Plants through Underground Common Mycorrhizal Networks

    Science.gov (United States)

    Song, Yuan Yuan; Zeng, Ren Sen; Xu, Jian Feng; Li, Jun; Shen, Xiang; Yihdego, Woldemariam Gebrehiwot

    2010-01-01

    Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plant-plant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of ‘donor’ plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring ‘receiver’ plants. The uninfected ‘receiver’ plants also activated six defence-related genes when CMNs connected ‘donor’ plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can ‘eavesdrop’ on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves. PMID:20967206

  13. [Diversity of arbuscular mycorrhizal fungi in special habitats: a review].

    Science.gov (United States)

    Li, Su-Mei; Wang, Yin-Qiao; Liu, Run-Jin

    2013-11-01

    Arbuscular mycorrhizal fungi (AMF) are one of the important components in ecosystems, which not only have the diversity in genetics, species composition, and function, but also have the diversity in distribution and habitat. AMF infect plant root, form mycorrhiza, and nourish as obligate biotroph symbiont, with strong ecological adaptability. They not only distribute in forest, prairie, and farm land, but also distribute in the special habitats with less plant species diversity, such as commercial greenhouse soil, saline-alkali soil, mining pollution land, petroleum-contaminated land, pesticide-polluted soil, desert, dry land, wetland, marsh, plateau, volcanic, cooler, and arctic tundra, composing a unique community structure and playing an important irreplaceable role in the physiological and ecological functions. This paper summarized the species diversity and mycorrhizal morphological features of AMF in special habitats, aimed to provide essential information for the further studies on the AMF in these special habitats and extreme environments.

  14. Mycorrhizal aspects in slope stabilisation

    Science.gov (United States)

    Graf, Frank

    2016-04-01

    In order to re-colonise and stabilise slopes affected by superficial soil failure with plants essential requirements have to be met: the plants must grow the plants must survive sustainably plant succession must start and continuously develop These requirements, however, are anything but easy given, particularly under the often hostile environmental conditions dominating on bare and steep slopes. Mycorrhizal fungi, the symbiotic partners of almost all plants used in eco-engineering, are said to improve the plants' ability to overcome periods governed by strongly (growth) limiting factors. Subsequently, results of investigations are presented of mycorrhizal effects on different plant and soil functions related to eco-engineering in general and soil and slope stabilisation in particular. Generally, inoculation yielded higher biomass of the host plants above as well as below ground. Furthermore, the survival rate was higher for mycorrhized compared to non-mycorrhized plants, particularly under extreme environmental conditions. However, the scale of the mycorrhizal impact may be species specific of both the plant host as well as the fungal partner(s) and often becomes evident only after a certain time lag. Depending on the plant-fungus combination the root length per soil volume was found to be between 0 and 2.5 times higher for inoculated compared to non-inoculated specimens. On an alpine graded ski slope the survival of inoculated compared to non-treated Salix herbacea cuttings was significant after one vegetation period only for one of the three added mycorrhizal fungus species. However, after three years all of the inoculated plantlets performed significantly better than the non-inoculated controls. The analysis of the potential for producing and stabilising soil aggregates of five different ectomycorrhizal fungi showed high variation and, for the species Inocybe lacera, no significant difference compared to untreated soil. Furthermore, inoculation of Salix

  15. EFFECTS OF MYCORRHIZAL FUNGI ON IN-VITRO NITROGEN RESPONSE OF SOME DUTCH INDIGENOUS ORCHID SPECIES

    NARCIS (Netherlands)

    DIJK, E; ECK, ND

    The effect of mycorrhizal infection on the response to mineral nitrogen was studied in Orchis morio L., Dactylorhiza praetermissa (Druce) Soo var. junialis (Vermin.) Sengh., Dactylorhiza majalis (Reichb.) Hunt & Summerh., and Dactylorhiza incarnara (L.) Soo, using two strains of Ceratorhiza sp. and

  16. Mycorrhizal status helps explain invasion success of alien plant species.

    Science.gov (United States)

    Menzel, Andreas; Hempel, Stefan; Klotz, Stefan; Moora, Mari; Pyšek, Petr; Rillig, Matthias C; Zobel, Martin; Kühn, Ingolf

    2017-01-01

    It is still debated whether alien plants benefit from being mycorrhizal, or if engaging in the symbiosis constrains their establishment and spread in new regions. We analyzed the association between mycorrhizal status of alien plant species in Germany and their invasion success. We compared whether the representation of species with different mycorrhizal status (obligate, facultative, or non-mycorrhizal) differed at several stages of the invasion process. We used generalized linear models to explain the occupied geographical range of alien plants, incorporating interactions of mycorrhizal status with plant traits related to morphology, reproduction, and life-history. Non-naturalized aliens did not differ from naturalized aliens in the relative frequency of different mycorrhizal status categories. Mycorrhizal status significantly explained the occupied range of alien plants; with facultative mycorrhizal species inhabiting a larger range than non-mycorrhizal aliens and obligate mycorrhizal plant species taking an intermediate position. Aliens with storage organs, shoot metamorphoses, or specialized structures promoting vegetative dispersal occupied a larger range when being facultative mycorrhizal. We conclude that being mycorrhizal is important for the persistence of aliens in Germany and constitutes an advantage compared to being non-mycorrhizal. Being facultative mycorrhizal seems to be especially advantageous for successful spread, as the flexibility of this mycorrhizal status may enable plants to use a broader set of ecological strategies. © 2016 by the Ecological Society of America.

  17. Phylogeonomics and Ecogenomics of the Mycorrhizal Symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Alan; Grigoriev, Igor V.; Kohler, Annegret; Martin, Francis

    2013-05-23

    Mycorrhizal fungi play critical roles in host plant health, soil community structure and chemistry, and carbon and nutrient cycling, all areas of intense interest to the US Dept. of Energy (DOE) Joint Genome Institute (JGI). To this end we are building on our earlier sequencing of the Laccaria bicolor genome by partnering with INRA-Nancy and the mycorrhizal research community in the MGI to sequence and analyze 2 dozen mycorrhizal genomes of numerous known mycorrhizal orders and several ecological types (ectomycorrhizal [ECM], ericoid, orchid, and arbuscular). JGI has developed and deployed high-throughput pipelines for genomic, transcriptomic, and re-sequencing, and platforms for assembly, annotation, and analysis. In the last 2 years we have sequenced 21 genomes of mycorrhizal fungi, and resequenced 6 additional strains of L. bicolor. Most of this data is publicly available on JGI MycoCosm?s Mycorrhizal Fungi Portal (http://jgi.doe.gov/Mycorrhizal_fungi/), which provides access to both the genome data and tools with which to analyze the data. These data allow us to address long-standing issues in mycorrhizal evolution and ecology. For example, a major observation of mycorrhizal evolution is that each of the major ecological types appears to have evolved independently in multiple fungal clades. Using an ecogenomic approach we provide preliminary evidence that 2 clades (Cantharellales and Sebacinales) of a single symbiotic ecotype (orchid) utilize some common regulatory (protein tyrosine kinase) and metabolic (lipase) paths, the latter of which may be the product of HGT. Using a phylogenomic approach we provide preliminary evidence that a particular ecotype (ericoid) may have evolved more than once within a major clade (Leotiomycetes).

  18. Saprotrophic fungal mycorrhizal symbionts in achlorophyllous orchids

    Science.gov (United States)

    Martos, Florent; Perry, Brian A; Padamsee, Mahajabeen; Roy, Mélanie; Pailler, Thierry

    2010-01-01

    Mycoheterotrophic plants are achlorophyllous plants that obtain carbon from their mycorrhizal fungi. They are usually considered to associate with fungi that are (1) specific of each mycoheterotrophic species and (2) mycorrhizal on surrounding green plants, which are the ultimate carbon source of the entire system. Here we review recent works revealing that some mycoheterotrophic plants are not fungal-specific, and that some mycoheterotrophic orchids associate with saprophytic fungi. A re-examination of earlier data suggests that lower specificity may be less rare than supposed in mycoheterotrophic plants. Association between mycoheterotrophic orchids and saprophytic fungi arose several times in the evolution of the two partners. We speculate that this indirectly illustrates why transition from saprotrophy to mycorrhizal status is common in fungal evolution. Moreover, some unexpected fungi occasionally encountered in plant roots should not be discounted as ‘molecular scraps’, since these facultatively biotrophic encounters may evolve into mycorrhizal symbionts in some other plants. PMID:20061806

  19. Effect of high soil copper concentration on mycorrhizal grapevines

    Science.gov (United States)

    Nogales, Amaia; Santos, Erika S.; Viegas, Wanda; Aran, Diego; Pereira, Sofia H.; Vidigal, Patricia; Lopes, Carlos M.; Abreu, M. Manuela

    2017-04-01

    dehydrogenase activity and the number of mycorrhizal infective propagules were evaluated in association with several plant physiological parameters (vegetative growth, NDVI‒Normalized Difference Vegetation Index and PRI‒Photochemical Reflectance Index, leaf nutrient content) and root mycorrhizal colonization percentage. Preliminary results indicate an overall decrease in soil microbial activity due to Cu addition, regardless of the presence or absence of the inoculated mycorrhizal fungus. High Cu concentrations in soil decreased plant shoot length, root fresh weight and NDVI and PRI values. However, differences between mycorrhizal treatments were detected on plant response to Cu stress. The usefulness of grapevine inoculation with AMF to enhance plant performance at high Cu levels in the soil is discussed.

  20. Arbuscular mycorrhizal fungi mediated uptake of {sup 137}Cs in leek and ryegrass

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Klas; Weiliang, Zhong; Maertensson, Anna [Department of Soil Sciences, Swedish University of Agricultural Sciences P.O. Box 7014, SE-750 07 Uppsala (Sweden)

    2005-02-15

    In a first experiment of soil contaminated with {sup 137}Cs, inoculation with a mixture of arbuscular mycorrhizae enhanced the uptake of {sup 137}Cs by leek under greenhouse conditions, while no effect on the uptake by ryegrass was observed. The mycorrhizal infection frequency in leek was independent of whether the {sup 137}Cs-contaminated soil was inoculated with mycorrhizal spores or not. The lack of mycorrhizae-mediated uptake of {sup 137}Cs in ryegrass could be due to the high root density, which was about four times that of leek, or due to a less well functioning mycorrhizal symbiosis than of leek. In a second experiment, ryegrass was grown for a period of four cuts. Additions of fungi enhanced {sup 137}Cs uptake of all harvests, improved dry weight production in the first cut, and also improved the mycorrhizal infection frequencies in the roots. No differences were obtained between the two fungal inoculums investigated with respect to biomass production or {sup 137}Cs uptake, but root colonization differed. We conclude that, under certain circumstances, mycorrhizae affect plant uptake of {sup 137}Cs. There may be a potential for selecting fungal strains that stimulate {sup 137}Cs accumulation in crops. The use of ryegrass seems to be rather ineffective for remediation of {sup 137}Cs-contaminated soil.

  1. Response of Mycorrhizal Diversity to Current Climatic Changes

    OpenAIRE

    Williams, Stephen E.; Stanley E. Bellgard

    2011-01-01

    Form and function of mycorrhizas as well as tracing the presence of the mycorrhizal fungi through the geological time scale are herein first addressed. Then mycorrhizas and plant fitness, succession, mycorrhizas and ecosystem function, and mycorrhizal resiliency are introduced. From this, four hypotheses are drawn: (1) mycorrhizal diversity evolved in response to changes in Global Climate Change (GCC) environmental drivers, (2) mycorrhizal diversity will be modified by present changes in GCC ...

  2. Diversity of arbuscular mycorrhizal fungi in Camellia sinensis in ...

    African Journals Online (AJOL)

    A study of diversity of arbuscular mycorrhizal fungi in Camellia sinensis was conducted in four plantation territories of Uttarakhand. Microscopic analysis of the mycorrhizal status of roots has revealed that samples from all four locations belonged only to AM fungi. The mycorrhizal colonization level was found high thus ...

  3. Auxin influences strigolactones in pea mycorrhizal symbiosis.

    Science.gov (United States)

    Foo, E

    2013-03-15

    Hormone interactions are essential for the control of many developmental processes, including intracellular symbioses. The interaction between auxin and the new plant hormone strigolactone in the regulation of arbuscular mycorrhizal symbiosis was examined in one of the few auxin deficient mutants available in a mycorrhizal species, the auxin-deficient bsh mutant of pea (Pisum sativum). Mycorrhizal colonisation with the fungus Glomus intraradices was significantly reduced in the low auxin bsh mutant. The bsh mutant also exhibited a reduction in strigolactone exudation and the expression of a key strigolactone biosynthesis gene (PsCCD8). Strigolactone exudation was also reduced in wild type plants when the auxin content was reduced by stem girdling. Low strigolactone levels appear to be at least partially responsible for the reduced colonisation of the bsh mutant, as application of the synthetic strigolactone GR24 could partially rescue the mycorrhizal phenotype of bsh mutants. Data presented here indicates root auxin content was correlated with strigolactone exudation in both mutant and wild type plants. Mutant studies suggest that auxin may regulate early events in the formation of arbuscular mycorrhizal symbiosis by controlling strigolactone levels, both in the rhizosphere and possibly during early root colonisation. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. Metabolic transition in mycorrhizal tomato roots

    Science.gov (United States)

    Rivero, Javier; Gamir, Jordi; Aroca, Ricardo; Pozo, María J.; Flors, Víctor

    2015-01-01

    Beneficial plant–microorganism interactions are widespread in nature. Among them, the symbiosis between plant roots and arbuscular mycorrhizal fungi (AMF) is of major importance, commonly improving host nutrition and tolerance against environmental and biotic challenges. Metabolic changes were observed in a well-established symbiosis between tomato and two common AMF: Rhizophagus irregularis and Funneliformis mosseae. Principal component analysis of metabolites, determined by non-targeted liquid chromatography–mass spectrometry, showed a strong metabolic rearrangement in mycorrhizal roots. There was generally a negative impact of mycorrhizal symbiosis on amino acid content, mainly on those involved in the biosynthesis of phenylpropanoids. On the other hand, many intermediaries in amino acid and sugar metabolism and the oxylipin pathway were among the compounds accumulating more in mycorrhizal roots. The metabolic reprogramming also affected other pathways in the secondary metabolism, mainly phenyl alcohols (lignins and lignans) and vitamins. The results showed that source metabolites of these pathways decreased in mycorrhizal roots, whilst the products derived from α-linolenic and amino acids presented higher concentrations in AMF-colonized roots. Mycorrhization therefore increased the flux into those pathways. Venn-diagram analysis showed that there are many induced signals shared by both mycorrhizal interactions, pointing to general mycorrhiza-associated changes in the tomato metabolome. Moreover, fungus-specific fingerprints were also found, suggesting that specific molecular alterations may underlie the reported functional diversity of the symbiosis. Since most positively regulated pathways were related to stress response mechanisms, their potential contribution to improved host stress tolerance is discussed. PMID:26157423

  5. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization

    Directory of Open Access Journals (Sweden)

    Rakshit Amitava

    2010-03-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.

  6. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization

    Directory of Open Access Journals (Sweden)

    Amitava Rakshit

    2010-01-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.

  7. Capacidade infectiva de fungos micorrízicos arbusculares em áreas reflorestadas após mineração de bauxita no Pará Infective capacity of arbuscular mycorrhizal fungi in reforested areas after bauxite mining in the Pará State, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Lucy Caproni

    2003-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a capacidade infectiva das espécies de fungos micorrízicos arbusculares (FMA e relacionála com o número mais provável (NMP de propágulos infectivos e número de esporos extraídos diretamente do campo. Amostras de solo foram coletadas em áreas degradadas pela mineração de bauxita com cobertura de 2, 6, 12 e 16 anos após revegetação e em uma área de floresta primária, em Porto Trombetas, PA. Os esporos de FMA foram extraídos e identificados taxonomicamente por suas características morfológicas. A maioria das espécies apresentou comportamento diferente nas áreas em estudo. Glomus macrocarpum foi a que apresentou infectividade mais rápida e alto potencial infectivo, nos solos das cinco áreas estudadas. Esta espécie também apresentou alto NMP de propágulos e alto número de esporos em todas as áreas estudadas. A capacidade infectiva das espécies não está relacionada com a densidade de propágulos. As espécies de FMA possuem diferentes graus de tolerância às condições de solo e se comportaram de maneira diferente de acordo com a idade da revegetação.The objective of this work was to evaluate the infective capacity of arbuscular mycorrhizal fungi (AMF species and relate it to the most probable number (MPN of infective propagules and number of spores extracted directly from the field. Soil samples were taken from areas degraded by bauxite mining, 2, 6, 12 and 16 years after reforestation and from an area of primary forest. The spores were extracted and morphologically identified. Most of the species had different behavior for the areas of study. Glomus macrocarpum showed fast infectivity in soils with high infective potential, independently of the soil origin. This species also showed high MPN values of infective propagules and high number of spores in all areas. The infective capacity of the species did not relate to the density of infective propagules. AMF species have different

  8. Widespread mycorrhizal specificity correlates to mycorrhizal function in the neotropical, epiphytic orchid Ionopsis utricularioides (Orchidaceae).

    Science.gov (United States)

    Otero, J Tupac; Flanagan, Nicola S; Herre, E Allen; Ackerman, James D; Bayman, Paul

    2007-12-01

    Tropical orchids constitute the greater part of orchid diversity, but little is known about their obligate mycorrhizal relationships. The specificity of these interactions and associated fungal distributions could influence orchid distributions and diversity. We investigated the mycorrhizal specificity of the tropical epiphytic orchid Ionopsis utricularioides across an extensive geographical range. DNA ITS sequence variation was surveyed in both plants and mycorrhizal fungi. Phylogeographic relationships were estimated for the mycorrhizal fungi. Orchid functional outcomes were determined through in vitro seed germination and seedling growth with a broad phylogenetic representation of fungi. Most fungal isolates derived from one clade of Ceratobasidium (anamorphs assignable to Ceratorhiza), with 78% within a narrower phylogenetic group, clade B. No correlation was found between the distributions of orchid and fungal genotypes. All fungal isolates significantly enhanced seed germination, while fungi in clade B significantly enhanced seedling growth. These results show that I. utricularioides associates with a phylogenetically narrow, effective fungal clade over a broad distribution. This preference for a widespread mycorrhizae may partly explain the ample distribution and abundance of I. utricularioides and contrasts with local mycorrhizal diversification seen in some nonphotosynthetic orchids. Enhanced orchid function with a particular fungal subclade suggests mycorrhizal specificity can increase orchid fitness.

  9. Mycorrhizal symbiosis enhances Phalaenopsis orchid's growth and ...

    African Journals Online (AJOL)

    Administrator

    2011-09-05

    Sep 5, 2011 ... mycorrhizal associations: Comparisons with the Rhizobium-legume symbiosis. Fungal Genet. Biol. 23: 205-212. Johnson TR, Stewart SL, Dytra D, Kane ME, and Richardson L (2007). Asymbiotic and symbiotic seed germination of Eulophia alta. (Orchidaceae)-preliminary evidence for the symbiotic culture.

  10. Response of Arbuscular mycorrhizal fungi and Rhizobium ...

    African Journals Online (AJOL)

    Michael Horsfall

    the alternative sources to meet the nutrient requirement of crops. Arbuscular Mycorrhizal (AM) fungi are found in many soils around the w orld, and they form association with 80% of all terrestrial plant roots (Harley and Harley, 1987). The beneficial effects of AM fungi symbiotic association on the growth of plants are well ...

  11. Response of Arbuscular mycorrhizal fungi and Rhizobium ...

    African Journals Online (AJOL)

    The aim of the present study was to investigate the effect ofRhizobium and Arbuscular mycorrhizal fungi inoculation, both individually and in combination on growth and chlorophyll content of economically important plant Vigna unguiculata L. A significant (p < 0.05) increase over control in root length (45.6 cm), shoot height ...

  12. Interaction of arbuscular mycorrhizal fungus ( Glomus intraradices ...

    African Journals Online (AJOL)

    In this research, the effect of two arbuscular mycorrhizal fungal (AMF) inoculation (Glomus intraradices and Glomus etunicatum) on tomato plants growing in nutrient solution with high concentrations of copper were studied. Copper (Cu) is an essential micronutrient for plant growth. In the present study, the effect of copper ...

  13. Composition of arbuscular mycorrhizal fungi associated with ...

    African Journals Online (AJOL)

    Composition of arbuscular mycorrhizal fungi associated with cassava (Manihot esculenta Crantz) cultivars as influenced by chemical fertilization and tillage in Cameroon. Didier Aime Boyogueno Begoude, Papa Saliou Sarr, Tatiana Laure Yondi Mpon, Didier Alexis Owona, Miraine Ndacnou Kapeua, Shigeru Araki ...

  14. Arbuscular mycorrhizal infection in two morphological root types of Araucaria araucana (Molina K. Koch Infección por micorrizas arbusculares en dos tipos de raíces de Araucaria araucana (Molina K. Koch

    Directory of Open Access Journals (Sweden)

    P. Diehl

    2010-06-01

    Full Text Available Araucaria araucana (Molina K. Koch is a conifer distributed in the Andean-Patagonian forests in the south of Argentina and Chile. The main objective of this work was to relate the different root classes appearing in A. araucana to mycorrhizal behavior. Samples were collected in three different sites in the Lanín National Park (NW Patagonia, Argentina. Two different root classes were present in A. araucana: longitudinal fine roots (LFR and globular short roots (GSR. Both had extensive mycorrhizal arbuscular symbiosis (AM and presented abundant hyphae and coils in root cells, a characteristic of the anatomical Paris-type. Dark septate fungal endophytes were also observed. Values of total AM colonization were high, with similar partial AM% values for each root class. Seasonal differences were found for total and partial colonization, with higher values in spring compared to autumn. Regarding the percentage of fungal structures between root classes, values were similar for vesicles and arbuscules, but higher coil percentages were observed in GSR compared to LFR. The percentages of vesicles increased in autumn, whereas the arbuscule percentages increased in spring, coinciding with the plant growth peak. Results show that both root classes of A. araucana in Andean-Patagonian forests are associated with AM fungi, which may have ecological relevance in terms of the importance of this symbiosis, in response to soil nutrient-deficiencies, especially high P-retention.La conífera Araucaria araucana (Molina K. Koch se encuentra distribuida en los bosques Andino-Patagónicos de Argentina y Chile. En este trabajo se relacionaron las diferentes clases morfológicas de raíces presentes en la especie con el comportamiento micorrícico. Las muestras fueron tomadas en tres sitios del Parque Nacional Lanín (NO de Patagonia, Argentina. Se observaron dos clases diferentes de raíces: raíces finas longitudinales (RFL y raíces cortas globulares (RCG. Ambas clases

  15. The Physiological Response of Soybean Genotypes to VAM Inoculation on Selected Drought Stress Levels

    Directory of Open Access Journals (Sweden)

    HAPSOH

    2006-06-01

    Full Text Available Present research was aimed to study physiological changes of soybean which were inoculated with vesicular arbuscular mycorrhizal fungi (VAM. Glomus etunicatum was exposed to moderate and severe drought condition. Symbiotic association with VAM improved adaptability as it was shown by the increasing leaf proline content. The MLG 3474 and Sindoro are the more tolerant genotypes while the responses of plant to VAM on improving the adaptability to drought were larger on Lokon.

  16. Community assembly and coexistence in communities of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Vályi, Kriszta; Mardhiah, Ulfah; Rillig, Matthias C; Hempel, Stefan

    2016-10-01

    Arbuscular mycorrhizal fungi are asexual, obligately symbiotic fungi with unique morphology and genomic structure, which occupy a dual niche, that is, the soil and the host root. Consequently, the direct adoption of models for community assembly developed for other organism groups is not evident. In this paper we adapted modern coexistence and assembly theory to arbuscular mycorrhizal fungi. We review research on the elements of community assembly and coexistence of arbuscular mycorrhizal fungi, highlighting recent studies using molecular methods. By addressing several points from the individual to the community level where the application of modern community ecology terms runs into problems when arbuscular mycorrhizal fungi are concerned, we aim to account for these special circumstances from a mycocentric point of view. We suggest that hierarchical spatial structure of arbuscular mycorrhizal fungal communities should be explicitly taken into account in future studies. The conceptual framework we develop here for arbuscular mycorrhizal fungi is also adaptable for other host-associated microbial communities.

  17. Plant Functional Traits Associated with Mycorrhizal Root Foraging in Arbuscular Mycorrhizal and Ectomycorrhizal Trees

    Science.gov (United States)

    Eissenstat, D. M.; Chen, W.; Cheng, L.; Liu, B.; Koide, R. T.; Guo, D.

    2016-12-01

    Root foraging for nutrient "hot spots" is a key strategy by which some plants maximize nutrient gain from their carbon investment in root and mycorrhizal hyphae. Foraging strategies may depend on costs of root construction, with thick roots generally costing more per unit length than thin roots. Investment in mycorrhizal hyphae, which are considerably thinner than roots, may represent an alternative strategy for cost-effective nutrient foraging, especially for thick-root species. Type of mycorrhiza may matter, as ectomycorrhizal (EM) fungi are more associated with longer hyphae and ability to mineralize organic matter than arbuscular mycorrhizal (AM) fungi. Among AM trees in both subtropical forests in SE China and in temperate forests in central Pennsylvania, USA, we found that tree species with thin roots proliferated their roots in soil patches enriched with mineral nutrients to a greater extent than species with thick roots. In addition, thick-root species were consistently colonized more heavily with mycorrhizal fungi than thin root species, although nutrient addition tended to diminish colonization. In a common garden in central Pennsylvania of both AM and EM tree species, we found that nutrient patches enriched with organic materials resulted in greater root and mycorrhizal fungal proliferation compared to those enriched with inorganic nutrients and that thick-root species proliferated more with their mycorrhizal fungi whereas thin-root species proliferated more with their roots. We further examined with many more species, patterns of root and mycorrhizal fungal proliferation in organic-nutrient-enriched patches. Foraging precision, or the extent that roots or mycorrhizal hyphae grew in the enriched patch relative to the unenriched patch, was related to both root thickness and type of mycorrhiza. In both AM and EM trees, thick-root species were not selective foragers of either their roots or hyphae. In thin-root species, there was strong selectivity in

  18. Cell wall remodeling in mycorrhizal symbiosis: a way towards biotrophism

    National Research Council Canada - National Science Library

    Balestrini, Raffaella; Bonfante, Paola

    2014-01-01

    .... All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged...

  19. Occurrence and succession of mycorrhizas in Alnus incana

    Energy Technology Data Exchange (ETDEWEB)

    Arveby, A.S. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Section of Forest Ecophysiology; Granhall, U. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Microbiology

    1998-12-31

    The occurrence of different mycorrhizas of the grey alder, Alnus incana (L.) Moench., in Sweden was investigated. Root sampling was carried out in planted and natural grey alder stands, representing different soil types, geographical sites, and plant ages. Mycorrhizal infection of roots was found to be frequent at all investigated sites, except for some planted peat bogs, where alders do not occur naturally. At the latter sites, mycorrhizal infection was less frequent and consisted only of ectomycorrhizas. Young trees here were non-mycorrhizal. At all other sites vesicular-arbuscular mycorrhiza (VAM) was found to be the almost exclusive type of mycorrhiza in first-year seedlings. In trees older than one year ectomycorrhiza was the dominating type. In the planted stands up to five years of age no fruitbodies of ectomycorrhizal fungi were found. In such stands the ectomycorrhizas generally had thin, translucent mantles and could be observed only by microscopic examination. In one old plantation (27 years) and in the natural stands sporocarps of several specific `alder fungi` were found. Here, the mycorrhizal root tips had thick, mostly whitish mantles. The Hartig net was in all cases confined to penetration between epidermal cells. Soil collected from one alder site and two non-alder biotopes readily infected grey alder seedlings with Frankia and VAM fungi whereas a peat soil failed to infect seedlings with any symbiont. In vitro inoculation of nodulated seedlings with Glomus mossae (Nicol. and Gerd.) Gerdemann and Trappe resulted in VAM-infection. Simultaneous syntheses with isolates of alder-specific, and other, ectomycorrhizal fungi, using three different methods, failed. On the basis of these results an endomycorrhizal-ectomycorrhizal succession after the first growth season in Alnus incana is concluded. A subsequent succession of ectomycorrhizal species from early-stage to late-stage ones is discussed 58 refs, 3 figs, 2 tabs

  20. Dioecious species and arbuscular mycorrhizal symbioses

    Science.gov (United States)

    Vega-Frutis, Rocío; Varga, Sandra; Kytöviita, Minna-Maarit

    2013-01-01

    Sex-specific interactions with herbivores and pollinators have been observed in female and male plants of dioecious species. However, only a limited number of studies have revised sex-specific patterns in mycorrhizal symbiosis. To test whether female and male plants of Antennaria dioica differ in their relationship with arbuscular mycorrhizal (AM) fungi, we examined the temporal and spatial variation in AM fungi in female, male and non-reproductive A. dioica plants in three natural populations in Finland during flowering and after seed production. Our results are consistent with previous studies both under greenhouse and field conditions with the same species showing differences in AM colonization between the sexes linked with allocation to reproduction. Taken together, the results indicate that there is a sex-specific interaction between A. dioica and AM fungi. Overall, females have a greater investment in AM fungi, likely to enhance their uptake of soil nutrients and support the reproduction by seed. PMID:23299337

  1. Phosphatase activity in sandy soil influenced by mycorrhizal and non-mycorrhizal cover crops

    Directory of Open Access Journals (Sweden)

    Alceu Kunze

    2011-06-01

    Full Text Available Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat (Avena strigosa Schreb or the non-mycorrhizal species oilseed radish (Raphanus sativus L. var. oleiferus Metzg and corn spurry (Spergula arvensis L.. The control treatment consisted of resident vegetation (fallow in the winter season. In the summer, a mixture of pearl millet (Pennisetum americanum L. with sunnhemp (Crotalaria juncea L. or with soybean (Glycine max L. was sown in all plots. Soil cores (0-10 cm and root samples were collected in six growing seasons (winter and summer of each year. Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35 % higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.

  2. Mycorrhizal diversity and specificity in Lecanorchis (Orchidaceae).

    Science.gov (United States)

    Okayama, Masanari; Yamato, Masahide; Yagame, Takahiro; Iwase, Koji

    2012-10-01

    Lecanorchis is a nonphotosynthetic plant genus in Vanilloideae, Orchidaceae. Because of the distribution of many Lecanorchis taxa in various climate conditions, we hypothesized that mycorrhizal diversity and specificity are different among the different taxa of Lecanorchis. In the present study, identities of mycorrhizal fungi were examined for 90 individuals of 10 Lecanorchis taxa at 26 sites from Niigata to Okinawa Prefectures in Japan. Phylogenetic analyses of Lecanorchis taxa based on the internal transcribed spacer (ITS) region of the nuclear ribosomal RNA gene (rDNA) divided the examined Lecanorchis taxa into three groups, groups A, B, and C. ITS rDNA sequences suggested that fungi associating with Lecanorchis were ectomycorrhiza-forming fungi in Lactarius, Russula, Atheliaceae, and Sebacina, with Lactarius and Russula dominant. Our results suggested some degree of mycorrhizal specialization among Lecanorchis taxa. Interestingly, the Lecanorchis group C had some specific relationships with Lactarius, whereas less specificity was found in the relationships with Russula. However, observed specificity results may be biased by geographic opportunity, and we suggest further research to assess whether Lecanorchis species are limited to the associations we observed.

  3. Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil

    Science.gov (United States)

    Gattai, Graziella S.; Pereira, Sônia V.; Costa, Cynthia M. C.; Lima, Cláudia E. P.; Maia, Leonor C.

    2011-01-01

    The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina) in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco). Dilutions were prepared by adding lead contaminated soil (270 mg Kg-1) to uncontaminated soil (37 mg Pb Kg soil-1) in the proportions of 7.5%, 15%, and 30% (v:v). The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30% contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil. PMID:24031701

  4. Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal ...

    African Journals Online (AJOL)

    Ouhmane

    In Morocco, the production of carob was estimated only to 8% of the world production. This production considered .... mycorrhizal maize roots were used for the control treatment. Mycorrhizal inoculation of C. siliqua seedlings and plant .... Hence the selection of efficient AM fungi is a key factor to ensure the success of soil.

  5. Does mycorrhizal specificity affect orchid decline and rarity?

    Science.gov (United States)

    Bailarote, Bruno Cachapa; Lievens, Bart; Jacquemyn, Hans

    2012-10-01

    Orchids rely on mycorrhizal fungi for seed germination, and many species maintain associations during later stages in their life cycle. Because of the critical dependence of orchids on fungi it has been suggested that the degree of mycorrhizal specificity may be associated with rarity and long-term survival of orchid species, especially in highly degraded or fragmented landscapes. To test this hypothesis, we compared mycorrhizal communities in two species that differed significantly in decline in Belgium and other parts of Europe. • Mycorrhizal associations were investigated in five populations of Anacamptis morio and Dactylorhiza fuchsii in Belgium. ITS-based DNA arrays were used for simultaneous detection and identification of a wide range of basidiomycetous mycorrhizal fungi. Mycorrhizal specificity, measured as phylogenetic diversity, was assessed for each population and compared between species. • For both species, the degree of phylogenetic relatedness of the mycorrhizal partners was low, and both species were associated with a large number of fungal lineages related to clades of the Tulasnellaceae family. Contrary to expectations, the species that was apparently resilient to decline was associated with fewer fungal operational taxonomical units than the declining species was, and the phylogenetic relatedness of mycorrhizal communities among populations was higher in the stable than in the declining orchid. • Although our results do not present detailed insights into the causes of orchid persistence, they do suggest that orchid rarity and persistence are not necessarily related to fungal diversity and that other factors may be more important in determining orchid persistence.

  6. Dominant forest tree mycorrhizal type mediates understory plant invasions

    Science.gov (United States)

    Insu Jo; Kevin M. Potter; Grant M. Domke; Songlin Fei

    2017-01-01

    Forest mycorrhizal type mediates nutrient dynamics, which in turn can influence forest community structure and processes. Using forest inventory data, we explored how dominant forest tree myc- orrhizal type affects understory plant invasions with consideration of forest structure and soil properties. We found that arbuscular mycorrhizal (AM) dominant forests, which are...

  7. Diversity of arbuscular mycorrhizal fungi in the rhizosphere of Coffea ...

    African Journals Online (AJOL)

    Objective: This study describes the status of mycorrhizal fungi in coffee (Coffea arabica) in the Yemeni ecosystems. Methodology and results: Soil samples were extracted from the rhizosphere of the coffee tree groves in several regions of Yemen. The frequency and the level of colonization of the arbuscular mycorrhizal fungi ...

  8. Potential to breed for mycorrhizal association in durum wheat.

    Science.gov (United States)

    Ellouze, Walid; Hamel, Chantal; DePauw, R M; Knox, R E; Cuthbert, Richard D; Singh, Asheesh K

    2016-03-01

    The selection of genotypes under high soil fertility may alter the effectiveness of mycorrhizal symbioses naturally forming between crop plants and the mycorrhizal fungi residing in cultivated fields. We tested the hypothesis that the mycorrhizal symbiosis of 5 landraces functions better than the mycorrhizal symbiosis of 27 cultivars of durum wheat that were bred after the development of the fertilizer industry. We examined the development of mycorrhiza and the response of these genotypes to mycorrhiza formation after 4 weeks of growth under high and low soil fertility levels in the greenhouse. The durum wheat genotypes were seeded in an established extraradical hyphal network of Rhizophagus irregularis and in a control soil free of mycorrhizal fungi. The percentage of root length colonized by mycorrhizal fungi was lower in landraces (21%) than in cultivars (27%; P = 0.04) and in the most recent releases (29%; P = 0.02), which were selected under high soil fertility levels. Plant growth response to mycorrhiza varied from -36% to +19%. Overall, durum wheat plant breeding in Canada has increased the mycorrhizal development in wheat grown at a low soil fertility level. However, breeding had inconsistent effects on mycorrhizal development and has led to the production of cultivars with patterns of regulation ranging from unimproved to inefficient.

  9. Effects of arbuscular mycorrhizal fungi on resistance to Phytophthora ...

    African Journals Online (AJOL)

    xp

    2012-06-28

    Jun 28, 2012 ... mycorrhizal (AM) fungi and Phytophthora parasitica of different citrus genotypes and the effect of AM fungi on the growth of ... Key words: Phytophthora parasitica, citrus, rootstock, arbuscular mycorrhizal (AM) fungi, root rot. INTRODUCTION ... It belongs in the kingdom Stramenopila, phylum Oomycota, and ...

  10. Colonization of new land by arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Nielsen, Knud Nor; Kjøller, Rasmus; Bruun, Hans Henrik

    2016-01-01

    The study describes the primary assembly of arbuscular mycorrhizal communities on a newly constructed island Peberholm between Denmark and Sweden. The AM fungal community on Peberholm was compared with the neighboring natural island Saltholm. The structure of arbuscular mycorrhizal communities wa...

  11. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    Effect of arbuscular mycorrhizal fungal inoculation on growth, and nutrient uptake of the two grass species, Leptochloa fusca (L.) Stapf and Sporobolus robustus ... MD and shoot mineral contents (especially P) varied with AMF host plants. ... Key words: Grass species, symbiosis, mycorrhizal dependency, mineral nutrition.

  12. Mycorrhizal status of Lycium europaeum in the coastal dunes of ...

    African Journals Online (AJOL)

    Objective: This study describes the mycorrhizal status of Lycium europaeum in the mobile and fixed dunes in the coastal area of Mehdia (Northwest of Morocco). Methodology and results: Evaluation of the mycorrhization level in the roots was effected and the identification of the arbuscular mycorrhizal fungi was based on ...

  13. Contribution of arbuscular mycorrhizal fungus to red kidney and ...

    African Journals Online (AJOL)

    The researcher had investigated the role of arbuscular mycorrhizal fungal inoculation in red idney and wheat in heavy metals tolerance in soil artificially contaminated with high oncentrations of zinc, copper, lead and cadmium. Metals accumulated by mycorrhizal wheat lants were mostly distributed in root tissues, suggesting ...

  14. Molecular characterisation of a mycorrhizal inoculant that enhances ...

    African Journals Online (AJOL)

    The occurrence of drought is an economically important problem in Morocco. The use of mycorrhizal technology offers a possibility to overcome this problem. A mycorrhizal fungal inoculum “Aoufous Complex” isolated in Morocco was shown to enhance Trifolium alexandrium resistance in water deficit situation.

  15. Mycorrhizal status of Olea europaea spp. oleaster in Morocco | Sghir ...

    African Journals Online (AJOL)

    Objective: This study describes the mycorrhizal oleaster status (Olea europaea ssp. oleaster:) in the Moroccan ecosystems. Methodology and results: Soil samples were extracted from the rhizosphere of the oleaster tree groves in several regions of Morocco. The frequency and the levels of the arbuscular mycorrhizal fungi ...

  16. Mycorrhizal population on various cropping systems on sandy soil in dryland area of North Lombok, Indonesia

    Directory of Open Access Journals (Sweden)

    WAHYU ASTIKO

    2016-01-01

    Full Text Available Abstract. Astiko W, Fauzi MT, Sukartono. 2016. Mycorrhizal population on various cropping systems on sandy soil in dryland area of North Lombok, Indonesia. Nusantara Bioscience 8: 66-70. Inoculation of arbuscular mycorrhizal fungi (AMF on maize in sandy soil is expected to have positive implications for the improvement of AMF population and nutrient uptake. However, how many increases in the AMF population and nutrient uptake in the second cycle of a certain cropping system commonly cultivated by the farmers after growing their corn crop have not been examined. Since different cropping systems would indicate different increases in the populations of AMF and nutrient uptake. This study aimed to determine the population AMF and nutrient uptake on the second cropping cycle of corn-based cropping systems which utilized indigenous mycorrhizal fungi on sandy soil in dryland area of North Lombok, West Nusa Tenggara, Indonesia. For that purpose, an experiment was conducted at the Akar-Akar Village in Bayan Sub-district of North Lombok, designed according to the Randomized Complete Block Design, with four replications and six treatments of cropping cycles (P0 = corn-soybean as a control, in which the corn plants were not inoculated with AMF; P1 = corn-soybean, P2 = corn-peanut, P3 = corn-upland rice, P4 = corn-sorghum, and P5 = corn-corn, in which the first cycle corn plants were inoculated with AMF. The results indicated that the mycorrhizal populations (spore number and infection percentage were highest in the second cycle sorghum, achieving 335% and 226% respectively, which were significantly higher than those in the control. Increased uptake of N, P, K and Ca the sorghum plants at 60 DAS of the second cropping cycle reached 200%; 550%; 120% and 490% higher than in the control. The soil used in this experiment is rough-textured (sandy loam, so it is relatively low in water holding capacity and high porosity.

  17. Influence of mycorrhizal developmental stages and plant age on rhizosphere mycoflora of Pinus kesiya (Royle

    Directory of Open Access Journals (Sweden)

    G. D. Sharma

    2014-08-01

    Full Text Available Quantitatively the population was recorded to be high around thc mycorrhizal roots. Some fungi were specific to different stages of mycorrhizal development. Rhizopus nigricans and Cunninghamella elegans were recorded at 5% mycorrhizal association stage. Fusarium sp. was found at 20% mycorrhizal association, while Mucor spp. were obtained at 60% stage. Verticillium sp. had the highest frequency of occurrence in the beginning of mycorrhizal association but later on Penicilium spp. were found to be the most common. Sugar content of mycorrhizal and nonmycorrhizal roots were determined to assess their effect on the mycorrhizospheric micropopulation. The mannitol and trehalose were present only in mycorrhizal roots.

  18. Dominant forest tree mycorrhizal type mediates understory plant invasions.

    Science.gov (United States)

    Jo, Insu; Potter, Kevin M; Domke, Grant M; Fei, Songlin

    2018-02-01

    Forest mycorrhizal type mediates nutrient dynamics, which in turn can influence forest community structure and processes. Using forest inventory data, we explored how dominant forest tree mycorrhizal type affects understory plant invasions with consideration of forest structure and soil properties. We found that arbuscular mycorrhizal (AM) dominant forests, which are characterised by thin forest floors and low soil C : N ratio, were invaded to a greater extent by non-native invasive species than ectomycorrhizal (ECM) dominant forests. Understory native species cover and richness had no strong associations with AM tree dominance. We also found no difference in the mycorrhizal type composition of understory invaders between AM and ECM dominant forests. Our results indicate that dominant forest tree mycorrhizal type is closely linked with understory invasions. The increased invader abundance in AM dominant forests can further facilitate nutrient cycling, leading to the alteration of ecosystem structure and functions. © 2017 John Wiley & Sons Ltd/CNRS.

  19. The role of mycorrhizal symbiosis in aluminum and phosphorus interactions in relation to aluminum tolerance in soybean.

    Science.gov (United States)

    Zhang, Shuang; Zhou, Jia; Wang, Guihua; Wang, Xiurong; Liao, Hong

    2015-12-01

    Arbuscular mycorrhizal (AM) fungi protect plants against aluminum (Al) toxicity, but the mechanisms of Al and phosphorus (P) interactions in relation to Al tolerance in mycorrhizal plants are only poorly understood. In this study, varying Al and P treatments were applied to soybean plants cultivated in the presence or absence of three different AM fungi. The results showed that plants in symbiotic association with Gigaspora margarita displayed higher Al tolerance than Rhizophagus irregularis or Glomus claroideum. The effectiveness of G. margarita appeared to be associated with more abundant arbuscules and less affected intraradical hyphae compared to no Al controls. The highest levels of Al toxicity mitigation were observed with the combination of high P availability and AM fungal inoculation, which was associated with a concomitant increase in the expression of the AM-inducible phosphate (Pi) transporter gene GmPT9 in soybean. Taken together, these results suggest that AM symbiosis can alleviate Al toxicity in soybean through enhanced P nutrition, as well as, the alteration of the abundance of mycorrhizal infection structures. These findings highlight the importance of P nutrition status in ameliorating Al toxicity in mycorrhizal plants.

  20. Differential access to phosphorus pools of an Oxisol by mycorrhizal and non-mycorrhizal maize

    NARCIS (Netherlands)

    Cardoso, I.M.; Boddington, C.L.; Janssen, B.H.; Oenema, O.; Kuyper, T.W.

    2006-01-01

    This study investigated whether arbuscular mycorrhizal fungi (AMF) could take up phosphorus (P) from pools that are normally considered unavailable to plants. An aluminum (Al) resistant maize variety, inoculated with three species of Glomus or uninoculated, supplied with nutrient solution without P,

  1. Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

    DEFF Research Database (Denmark)

    Larsen, John; Graham, James H.; Cubero, Jaime

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reduci...... AM fungi may offer plant beneficial traits in terms of biocontrol of root cortical pathogens.......Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reducing...... the pathogen root infection level, measured both in terms of Pythium ELISA and by recovery on selective media and only at the first harvest. Likewise, P. aphanidermatum root infection reduced colonization levels of G. intraradices, but not that of the two other AM fungi. In conclusion, plant growth suppressive...

  2. Spore communities of arbuscular mycorrhizal fungi and mycorrhizal associations in different ecosystems, south Australia

    Directory of Open Access Journals (Sweden)

    Z. I. Antoniolli

    2002-09-01

    Full Text Available Communities of arbuscular mycorrhizal fungi (AMF were surveyed in different South Australian ecosystems. The soil was wet-sieved for spore extraction, followed by the determination of presence and abundance of AMF species as well as the percentage of root colonization. Mycorrhizal associations were common and there was substantial fungal diversity in different ecosystems. Spores were most abundant in the permanent pasture system and less abundant under continuous wheat. The incidence of mycorrhizal associations in different plant species and the occurrence of Arum and Paris type colonization generally conformed with previous information. Spores of seventeen AMF were verified throughout seasonal changes in 1996 and 1997 in the permanent pasture and on four host species (Lolium perenne, Plantago lanceolata, Sorghum sp. and Trifolium subterraneum , set up with the same soils under greenhouse conditions. Glomus mosseae was the dominant spore type at all sampling times and in all trap cultures. Mycorrhizal diversity was significantly affected by different sampling times in trap cultures but not in field-collected soil. P. lanceolata, Sorghum sp. and T. subterraneum as hosts for trap cultures showed no differences in richness and diversity of AMF spores that developed in association with their roots. Abundance and diversity were lowest, however, in association with L. perenne , particularly in December 1996. Results show that the combination of spore identification from field-collected soil and trap cultures is essential to study population and diversity of AMF. The study provides baseline data for ongoing monitoring of mycorrhizal populations using conventional methods and material for the determination of the symbiotic effectiveness of AMF key members.

  3. Arbuscular mycorrhizal fungi and colonization stimulant in cotton and maize

    Directory of Open Access Journals (Sweden)

    Fabrício Henrique Moreira Salgado

    Full Text Available ABSTRACT: The objective of this study was to evaluate the effects of inoculation with different arbuscular mycorrhizal fungi native to Cerrado, associated with the application of colonization stimulant (7-hydroxy, 4’-methoxy-isoflavone at the initial growth of cotton and maize plants in a greenhouse. The experiment was carried out in a completely randomized design and 7x2 factorial scheme, with five species of arbuscular mycorrhizal fungi and combined inoculation (uniting all species in equal proportion and native fungi, in the presence and absence of colonization stimulant in maize and cotton crops. Shoots dry matter (SDM, roots dry matter (RDM, mycorrhizal colonization and accumulation of calcium, zinc and phosphorus in the SDM were evaluated at flowering. Inoculation of arbuscular mycorrhizal fungi and the use of colonization stimulant at low density of arbuscular mycorrhizal fungi propagules was beneficial to plant development. Inoculation with mycorrhizal fungi demonstrated different effects for the various parameters evaluated in cotton and maize, and the application of colonization stimulant promoted higher mycorrhizal colonization and initial growth in cotton, when associated with native AMF, and in corn, when associated with inoculation with Dentiscutata heterogama, Gigaspora margarita and Rhizophagus clarus.

  4. Are there keystone mycorrhizal fungi associated to tropical epiphytic orchids?

    Science.gov (United States)

    Cevallos, Stefania; Sánchez-Rodríguez, Aminael; Decock, Cony; Declerck, Stéphane; Suárez, Juan Pablo

    2017-04-01

    In epiphytic orchids, distinctive groups of fungi are involved in the symbiotic association. However, little is known about the factors that determine the mycorrhizal community structure. Here, we analyzed the orchid mycorrhizal fungi communities associated with three sympatric Cymbidieae epiphytic tropical orchids (Cyrtochilum flexuosum, Cyrtochilum myanthum, and Maxillaria calantha) at two sites located within the mountain rainforest of southern Ecuador. To characterize these communities at each orchid population, the ITS2 region was analyzed by Illumina MiSeq technology. Fifty-five mycorrhizal fungi operational taxonomic units (OTUs) putatively attributed to members of Serendipitaceae, Ceratobasidiaceae and Tulasnellaceae were identified. Significant differences in mycorrhizal communities were detected between the three sympatric orchid species as well as among sites/populations. Interestingly, some mycorrhizal OTUs overlapped among orchid populations. Our results suggested that populations of studied epiphytic orchids have site-adjusted mycorrhizal communities structured around keystone fungal species. Interaction with multiple mycorrhizal fungi could favor orchid site occurrence and co-existence among several orchid species.

  5. Further advances in orchid mycorrhizal research.

    Science.gov (United States)

    Dearnaley, John D W

    2007-09-01

    Orchid mycorrhizas are mutualistic interactions between fungi and members of the Orchidaceae, the world's largest plant family. The majority of the world's orchids are photosynthetic, a small number of species are myco-heterotrophic throughout their lifetime, and recent research indicates a third mode (mixotrophy) whereby green orchids supplement their photosynthetically fixed carbon with carbon derived from their mycorrhizal fungus. Molecular identification studies of orchid-associated fungi indicate a wide range of fungi might be orchid mycobionts, show common fungal taxa across the globe and support the view that some orchids have specific fungal interactions. Confirmation of mycorrhizal status requires isolation of the fungi and restoration of functional mycorrhizas. New methods may now be used to store orchid-associated fungi and store and germinate seed, leading to more efficient culture of orchid species. However, many orchid mycorrhizas must be synthesised before conservation of these associations can be attempted in the field. Further gene expression studies of orchid mycorrhizas are needed to better understand the establishment and maintenance of the interaction. These data will add to efforts to conserve this diverse and valuable association.

  6. NIN Is Involved in the Regulation of Arbuscular Mycorrhizal Symbiosis

    Science.gov (United States)

    Guillotin, Bruno; Couzigou, Jean-Malo; Combier, Jean-Philippe

    2016-01-01

    Arbuscular mycorrhizal (AM) symbiosis is an intimate and ancient symbiosis found between most of terrestrial plants and fungi from the Glomeromycota family. Later during evolution, the establishment of the nodulation between legume plants and soil bacteria known as rhizobia, involved several genes of the signaling pathway previously implicated for AM symbiosis. For the past years, the identification of the genes belonging to this Common Symbiotic Signaling Pathway have been mostly done on nodulation. Among the different genes already well identified as required for nodulation, we focused our attention on the involvement of Nodule Inception (NIN) in AM symbiosis. We show here that NIN expression is induced during AM symbiosis, and that the Medicago truncatula nin mutant is less colonized than the wild-type M. truncatula strain. Moreover, nin mutant displays a defect in the ability to be infected by the fungus Rhizophagus irregularis. This work brings a new evidence of the common genes involved in overlapping signaling pathways of both nodulation and in AM symbiosis. PMID:27899928

  7. NIN is involved in the regulation of Arbuscular Mycorrhizal symbiosis.

    Directory of Open Access Journals (Sweden)

    Bruno GUILLOTIN

    2016-11-01

    Full Text Available Arbuscular mycorrhizal (AM symbiosis is an intimate and ancient symbiosis found between most of terrestrial plants and fungi from the Glomeromycota family. Later during evolution, the establishment of the nodulation between legume plants and soil bacteria known as rhizobia, involved several genes of the signalling pathway previously implicated for AM symbiosis. For the past years, the identification of the genes belonging to this Common Symbiotic Signalling Pathway have been mostly done on nodulation. Among the different genes already well identified as required for nodulation, we focused our attention on the involvement of Nodule Inception (NIN in AM symbiosis. We show here that NIN expression is induced during AM symbiosis, and that the Medicago truncatula nin mutant is less colonized than the wild type M. truncatula strain. Moreover, nin mutant displays a defect in the ability to be infected by the fungus Rhizophagus irregularis. This work brings a new evidence of the common genes involved in overlapping signalling pathways of both nodulation and in AM symbiosis.

  8. Signaling events during initiation of arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Schmitz, Alexa M; Harrison, Maria J

    2014-03-01

    Under nutrient-limiting conditions, plants will enter into symbiosis with arbuscular mycorrhizal (AM) fungi for the enhancement of mineral nutrient acquisition from the surrounding soil. AM fungi live in close, intracellular association with plant roots where they transfer phosphate and nitrogen to the plant in exchange for carbon. They are obligate fungi, relying on their host as their only carbon source. Much has been discovered in the last decade concerning the signaling events during initiation of the AM symbiosis, including the identification of signaling molecules generated by both partners. This signaling occurs through symbiosis-specific gene products in the host plant, which are indispensable for normal AM development. At the same time, plants have adapted complex mechanisms for avoiding infection by pathogenic fungi, including an innate immune response to general microbial molecules, such as chitin present in fungal cell walls. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is still uncertain. In this review, we present a summary of the molecular signals and their elicited responses during initiation of the AM symbiosis, including plant immune responses and their suppression. © 2014 Institute of Botany, Chinese Academy of Sciences.

  9. NIN Is Involved in the Regulation of Arbuscular Mycorrhizal Symbiosis.

    Science.gov (United States)

    Guillotin, Bruno; Couzigou, Jean-Malo; Combier, Jean-Philippe

    2016-01-01

    Arbuscular mycorrhizal (AM) symbiosis is an intimate and ancient symbiosis found between most of terrestrial plants and fungi from the Glomeromycota family. Later during evolution, the establishment of the nodulation between legume plants and soil bacteria known as rhizobia, involved several genes of the signaling pathway previously implicated for AM symbiosis. For the past years, the identification of the genes belonging to this Common Symbiotic Signaling Pathway have been mostly done on nodulation. Among the different genes already well identified as required for nodulation, we focused our attention on the involvement of Nodule Inception (NIN) in AM symbiosis. We show here that NIN expression is induced during AM symbiosis, and that the Medicago truncatula nin mutant is less colonized than the wild-type M. truncatula strain. Moreover, nin mutant displays a defect in the ability to be infected by the fungus Rhizophagus irregularis. This work brings a new evidence of the common genes involved in overlapping signaling pathways of both nodulation and in AM symbiosis.

  10. Molecular trait indicators: moving beyond phylogeny in arbuscular mycorrhizal ecology.

    NARCIS (Netherlands)

    Gamper, H.A.; van der Heijden, M.G.A.; Kowalchuk, G.A.

    2010-01-01

    Arbuscular mycorrhizal (AM) fungi form symbiotic associations with the roots of most plants, thereby mediating nutrient and carbon fluxes, plant performance, and ecosystem dynamics. Although considerable effort has been expended to understand the keystone ecological position of AM symbioses, most

  11. Order of arrival structures arbuscular mycorrhizal colonization of plants

    NARCIS (Netherlands)

    Werner, G.D.A.; Kiers, E.T.

    2015-01-01

    Priority effects - the impact of a species' arrival on subsequent community development - have been shown to influence species composition in many organisms. Whether priority effects among arbuscular mycorrhizal fungi (AMF) structure fungal root communities is not well understood. Here, we

  12. Diversity and biogeography of arbuscular mycorrhizal fungi in agricultural soils

    Czech Academy of Sciences Publication Activity Database

    Oehl, F.; Laczko, E.; Oberholzer, H.-R.; Jansa, Jan; Egli, S.

    2017-01-01

    Roč. 53, č. 7 (2017), s. 777-797 ISSN 0178-2762 Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhizal * Agriculture * Biodiversity Subject RIV: EE - Microbiology, Virology Impact factor: 3.683, year: 2016

  13. Mycorrhizal responses to biochar in soil-concepts and mechanisms.

    NARCIS (Netherlands)

    Warnock, D.D.; Lehmann, J.; Kuyper, T.W.; Rillig, M.C.

    2007-01-01

    Experiments suggest that biomass-derived black carbon (biochar) affects microbial populations and soil biogeochemistry. Both biochar and mycorrhizal associations, ubiquitous symbioses in terrestrial ecosystems, are potentially important in various ecosystem services provided by soils, contributing

  14. Molecular characterisation of a mycorrhizal inoculant that enhances ...

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    . 1988; Smith and Read 1996, Smith et al. 1993). Under many natural or man made water stress conditions, arbuscular mycorrhizal fungi can play an important role. *Corresponding author. E-mail: zomure@yahoo.com. Tél: 00.

  15. Role of arbuscular mycorrhizal fungi in phytoremediation of heavy ...

    African Journals Online (AJOL)

    Role of arbuscular mycorrhizal fungi in phytoremediation of heavy metals and effects on growth and biochemical activities of wheat (Triticum aestivum L.) plants in Zn contaminated soils. Sadia Kanwal, Asma Bano, Riffat Naseem Malik ...

  16. Arbuscular mycorrhizal fungi and colonization stimulant in cotton and maize

    National Research Council Canada - National Science Library

    Fabrício Henrique Moreira Salgado; Fátima Maria de Sousa Moreira; José Oswaldo Siqueira; Ricardo Henrique Barbosa; Helder Barbosa Paulino; Marco Aurélio Carbone Carneiro

    The objective of this study was to evaluate the effects of inoculation with different arbuscular mycorrhizal fungi native to Cerrado, associated with the application of colonization stimulant (7-hydroxy, 4’-methoxy-isoflavone...

  17. Host plant quality mediates competition between arbuscular mycorrhizal fungi

    NARCIS (Netherlands)

    Knegt, B.; Jansa, J.; Franken, O.; Engelmoer, D.J.P.; Werner, G.D.A.; Bücking, H.; Kiers, E.T.

    2016-01-01

    Arbuscular mycorrhizal fungi exchange soil nutrients for carbon from plant hosts. Empirical works suggests that hosts may selectively provide resources to different fungal species, ultimately affecting fungal competition. However, fungal competition may also be mediated by colonization strategies of

  18. Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal ...

    African Journals Online (AJOL)

    Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal fungi mixture improves seedling establishment under greenhouse conditions. Ouahmane Lahcen, Ndoye Ibrahima, Morino Abdessadek, Ferradous Abderrahim, Sfairi Youssef, Al Faddy Mohamed Najib, Abourouh Mohamed ...

  19. Plant hormones as signals in arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Miransari, Mohammad; Abrishamchi, A; Khoshbakht, K; Niknam, V

    2014-06-01

    Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on mycorrhizal fungal symbiosis are reviewed. This may be useful for the production of plants, which are more responsive to mycorrhizal symbiosis under stress.

  20. Mycorrhizal symbiosis: ancient signalling mechanisms co-opted

    NARCIS (Netherlands)

    Geurts, R.; Vleeshouwers, V.G.A.A.

    2012-01-01

    Mycorrhizal root endosymbiosis is an ancient property of land plants. Two parallel studies now provide novel insight into the mechanism driving this interaction and how it is used by other filamentous microbes like pathogenic oomycetes.

  1. Communities, populations and individuals of arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Rosendahl, Søren

    2008-01-01

    Arbuscular mycorrhizal fungi in the phylum Glomeromycota are found globally in most vegetation types, where they form a mutualistic symbiosis with plant roots. Despite their wide distribution, only relatively few species are described. The taxonomy is based on morphological characters...... of the fungi has resulted in considerable genetic diversity within morphologically recognizable species, and challenges our concepts of individuals and populations. This review critically examines the concepts of species, communities, populations and individuals of arbuscular mycorrhizal fungi....

  2. Glyphosate drift affects arbuscular mycorrhizal association in coffee

    OpenAIRE

    Carvalho,F.P.; Souza,B.P.; França,A.C.; Ferreira,E.A.; Franco,M.H.R.; Kasuya,M.C.M.; Ferreira,F.A.

    2014-01-01

    Mycorrhizal association promotes better survival and nutrition of colonized seedling on field, and consequently, increasing of productivity. However, the weed management can interfere on this association, due to incorrect use of glyphosate. This work has assessed the effects of glyphosate drift on the growth and nutrition of arabica coffee plants (Catuaí Vermelho - IAC 99) colonized with arbuscular mycorrhizal fungi (AMF). The experiment was conducted in 2 x 5 factorial scheme, and included i...

  3. Effect of polyaromatic hydrocarbons in soil on arbuscular mycorrhizal plants

    Energy Technology Data Exchange (ETDEWEB)

    Leyval, C.; Binet, P. [H. Poincare University, Vandoeuvre-les-Nancy (France). Centre de Pedologie Biologique

    1998-03-01

    The rhizosphere of plants plays a role in the bioremediation of soils polluted with organic pollutants such as polyaromatic hydrocarbons (PAHs). Arbuscular mycorrhizal (AM) fungi provide a direct link between soil and plant roots, but very little is known of the interactions between PAHs and AM fungi. The effect of PAHs on mycorrhizal colonization in polluted soil were studied and the effect of AM fungi on plant growth in these soils. Lee (Allium porrum L.), maize (Zea mays L.), ryegrass (Lolium perenne L.), and clover (Trifolium subterraneum L.) were grown in pots containing a soil artificially contaminated with increasing concentrations of anthracene or mixed with an industrial soil polluted with PAHs. Mycorrhizal colonization by the indigenous AM population of the nonpolluted soil was not significantly affected by the addition of anthracene up to 10 g kg{sup -1}. However, mycorrhizal colonization of clover and leek decreased when the industrial soil was added to the nonpolluted soil, while maize and ryegrass colonization was not affected. The effect of PAHs on plant survival and growth depended on plant species. Inoculation of ryegrass with Glomus mosseae improved plant survival and plant growth in the industrially polluted soil. At 5 g of PAH kg{sup -1} only mycorrhizal plants survived. Mycorrhizal fungi may contribute to the establishment and maintenance of plants in PAH-polluted soils. 34 refs., 3 figs., 4 tabs.

  4. Growth responses of maritime sand dune plant species to arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Mariusz Tadych

    2014-08-01

    Full Text Available In a pot experiment conducted in a greenhouse, the response of 6 plant species dominating in the succession of vegetation of a deflation hollow of the Łeba Bar to inoculation with arbuscular mycorrhizal fungi (AMF was investigated. The inoculum was a mixture of soil, roots and spores of 5 species of AMF with the dominant species Glomus aggregatum. Except for Corynephorus canescens and Festuca rubra subsp. arenaria, both the growth and the dry matter of above-ground parts of plants of Agrostis stolonifera, Ammophila arenaria, Corynephorus canescens, Juncus articulatus and J. balticus inoculated with AMF were higher than those growing in soils lacking infection propagules of these fungi. Inoculation with AMF decreased the dry matter of root: shoot ratios in 5 plant species. This property was not determined in Festuca rubra subsp. arenaria due to the death of all control plants. The level of mycorrhizal infection was low and did not correlate with the growth responses found. The high growth reaction of Juncus spp. to AMF found in this study suggests that the opinion of non-mycotrophy or low dependence of plants of Juncaceae on AMF was based on results of investigations of plants growing in wet sites known to inhibit the formation of mycorrhizae.

  5. Cellular programs for arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Harrison, Maria J

    2012-12-01

    In arbuscular mycorrhizal (AM) symbiosis, AM fungi colonize root cortical cells to obtain carbon from the plant, while assisting the plant with the acquisition of mineral nutrients from the soil. Within the root cells, the fungal hyphae inhabit membrane-bound compartments that the plant establishes to accommodate the fungal symbiont. Recent data provide new insights into the events associated with development of the symbiosis including signaling for the formation of a cellular apparatus that guides hyphal growth through the cell. Plant genes that play key roles in a cellular program for the accommodation of microbial symbionts have been identified. In the inner cortical cells, tightly regulated changes in gene expression accompanied by a transient reorientation of secretion, enables the cell to build and populate the periarbuscular membrane with its unique complement of transporter proteins. Similarities between the cellular events for development of the periarbuscular membrane and cell plate formation are emerging. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Leaf metabolome in arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Schweiger, Rabea; Müller, Caroline

    2015-08-01

    Most land plants are associated with arbuscular mycorrhizal fungi, which colonise the plant roots and facilitate the uptake of water and nutrients. In turn, the fungi receive plant carbohydrates. Although the fungus is morphologically restricted to the roots, the exchange of substances and involvement of phytohormone signalling has consequences on systemic shoot tissues. Recent research provides growing insight in the species-specificity of leaf metabolic responses to arbuscular mycorrhiza, revealing that various metabolites can be affected. Such mycorrhiza-mediated changes in the chemical composition of leaf tissues can confer phytoprotection against different abiotic stresses. Moreover, they have consequences on numerous biotic interactions. In this review we highlight such findings and point out fields where more research is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Plant litter chemistry and mycorrhizal roots promote a nitrogen feedback in a temperate forest.

    Science.gov (United States)

    Nina Wurzburger; Ronald L. Hendrick

    2009-01-01

    1. Relationships between mycorrhizal plants and soil nitrogen (N) have led to the speculation that the chemistry of plant litter and the saprotrophy of mycorrhizal symbionts can function together to...

  8. Analysis of network architecture reveals phylogenetic constraints on mycorrhizal specificity in the genus Orchis (Orchidaceae)

    National Research Council Canada - National Science Library

    Hans Jacquemyn; Vincent Merckx; Rein Brys; Daniel Tyteca; Bruno P. A. Cammue; Olivier Honnay; Bart Lievens

    2011-01-01

    ... of the mycorrhizal specificity of orchids. Here, we used a network analysis approach to investigate orchid mycorrhizal associations in 16 species of the genus Orchis sampled across 11 different regions in Europe...

  9. Nitrogen Pollution Shifts Forest Mycorrhizal Associations at Continental Scale

    Science.gov (United States)

    Averill, C.; Talbot, J. M.; Dietze, M.

    2016-12-01

    Most trees on Earth form a symbiosis with either ectomycorrhizal or arbuscular mycorrhizal fungi. The type of association has demonstrated importance for understanding ecosystem carbon (C) and nitrogen (N) cycling. Furthermore, the effect is independent of other dominant drivers of ecosystem function: climate, mineralogy and organic matter chemistry. Given this, it becomes important to understand where different mycorrhizal associations are, what controls their distribution, and where they will be in the future. Here we analyze 3,000 forest inventory plots from the United State Forest Inventory and Analysis data set. We categorize forest basal area as ecto- or arbuscular mycorrhizal associated to generate a metric of the relative abundance of ectomycorrhizal trees (ectomycorrhizal basal area / ecto- + arbuscular mycorrhizal basal area). We model this abundance as a function of climate, soil chemical properties (pH and C:N stoichiometry), and atmospheric N deposition. We hypothesized that N pollution in the United States has affected the relative abundance of different mycorrhizal associations, and that this would be reflected in forest composition. Overall, models showed that climate, soil chemistry, and N deposition were important for predicting the current relative abundance of ecto- and arbuscular associated trees. Ectomycorrhizal trees were more abundant in cold and wet climates compared to hot and dry. Low soil pH and high soil C:N ratios were also associated with an increase in the relative abundance of ectomycorrhizal trees. Most interesting, there was a significant influence of N deposition on the relative abundance of different mycorrhizal associations. N deposition reduced the abundance of ectomycorrhizal compared to arbuscular mycorrhizal associated trees independent of climate and soil chemistry. Given the known associations between ectomycorrhizal dominance and soil C stabilization, we argue that N pollution in the United States has shifted the forest

  10. Mycorrhizal symbiosis produces changes in specific flavonoids in leaves of pepper plant (Capsicum annum L.)

    Science.gov (United States)

    In this study, experiments were performed to investigate if mycorrhizal plants grown under optimal growth conditions would improve crop quality compared to the non-mycorrhizal control. The results clearly showed that while mycorrhizal plants grown under an optimal nutrient supply did not increase t...

  11. Differences in arbuscular mycorrhizal fungi among three coffee cultivars in Puerto Rico

    Science.gov (United States)

    Ligia Lebrón; Jean D. Lodge; Paul. Bayman

    2012-01-01

    Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbon, at three farms in...

  12. Mycorrhizal inoculation affects the phytochemical content in strawberry fruits

    Directory of Open Access Journals (Sweden)

    Ana Paula Cecatto

    2016-04-01

    Full Text Available The aim of this research was to evaluate the effect of the inoculation date of arbuscular mycorrhizal fungi on the fruit quality and the content of phytochemicals in a strawberry soilless growing system. The experiment was performed in Huelva (Spain and was conducted in a greenhouse on the La Rábida Campus of Huelva University under natural light and temperature from October 2013 to June 2014. Three short-day strawberry cultivars (‘Splendor’, ‘Sabrina’ and ‘Fortuna’ were grown in polyethylene bags filled with coconut fibres. Randomized block design, with 3 repetitions and factorial arrangement (3 cultivars x 3 treatments, was established. Each replicate consisted of one bag with 12 plants supporting structures at 40 cm height. The treatments were: T1 = mycorrhizal inoculation in the transplantation; T2 = mycorrhizal inoculation 30 days after transplantation (DAT; and T0 = control treatment, without inoculation. Arbuscular mycorrhizal fungi inoculation significantly affected the contents of anthocyanin and phenolics. When the inoculation is performed in the transplantation, the fruits showed a high content of anthocyanin and total phenolics. The mycorrhizal inoculation influences decreasing the acidity in fruit throughout the growing season and increase firmness only during the early stage of production.

  13. Assembly, Annotation, and Analysis of Multiple Mycorrhizal Fungal Genomes

    Energy Technology Data Exchange (ETDEWEB)

    Initiative Consortium, Mycorrhizal Genomics; Kuo, Alan; Grigoriev, Igor; Kohler, Annegret; Martin, Francis

    2013-03-08

    Mycorrhizal fungi play critical roles in host plant health, soil community structure and chemistry, and carbon and nutrient cycling, all areas of intense interest to the US Dept. of Energy (DOE) Joint Genome Institute (JGI). To this end we are building on our earlier sequencing of the Laccaria bicolor genome by partnering with INRA-Nancy and the mycorrhizal research community in the MGI to sequence and analyze dozens of mycorrhizal genomes of all Basidiomycota and Ascomycota orders and multiple ecological types (ericoid, orchid, and ectomycorrhizal). JGI has developed and deployed high-throughput sequencing techniques, and Assembly, RNASeq, and Annotation Pipelines. In 2012 alone we sequenced, assembled, and annotated 12 draft or improved genomes of mycorrhizae, and predicted ~;;232831 genes and ~;;15011 multigene families, All of this data is publicly available on JGI MycoCosm (http://jgi.doe.gov/fungi/), which provides access to both the genome data and tools with which to analyze the data. Preliminary comparisons of the current total of 14 public mycorrhizal genomes suggest that 1) short secreted proteins potentially involved in symbiosis are more enriched in some orders than in others amongst the mycorrhizal Agaricomycetes, 2) there are wide ranges of numbers of genes involved in certain functional categories, such as signal transduction and post-translational modification, and 3) novel gene families are specific to some ecological types.

  14. Mycorrhizal associations as Salix repens L. communities in succession of dune ecosystems II Mycorrhizal dynamics and interactions of ectomycorrhizal and arbuscular mycorrhizal fungi

    NARCIS (Netherlands)

    Heijden, van der E.W.; Vosatka, M.

    2000-01-01

    Ectomycorrhizal (EcM) and arbuscular mycorrhizal (AM) associations of Salix repens were studied at 16 sites in different successional stages of dune ecosystems (calcareous-acidic, dry-wet) in the Netherlands. High EcM colonization, low AM colonization, and lack of differences between habitats

  15. Infection

    Science.gov (United States)

    2010-09-01

    whether BMPs maintain their osteoinductive capability in infected human wounds. The authors are aware of only one series describing the use of BMP in an...et al. Osteogenic protein-1 induces bone formation in the presence of bacterial infection in a rat intramuscular osteoinduction model. J Orthop Trauma

  16. Suppression of fungal and nematode plant pathogens through arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Veresoglou, Stavros D; Rillig, Matthias C

    2012-04-23

    Arbuscular mycorrhizal (AM) fungi represent ubiquitous mutualists of terrestrial plants. Through the symbiosis, plant hosts, among other benefits, receive protection from pathogens. A meta-analysis was conducted on 106 articles to determine whether, following pathogen infection of AM-colonized plants, the identity of the organisms involved (pathogens, AM fungi and host plants) had implications for the extent of the AM-induced pathogen suppression. Data on fungal and nematode pathogens were analysed separately. Although we found no differences in AM effectiveness with respect to the identity of the plant pathogen, the identity of the AM isolate had a dramatic effect on the level of pathogen protection. AM efficiency differences with respect to nematode pathogens were mainly limited to the number of AM isolates present; by contrast, modification of the ability to suppress fungal pathogens could occur even through changing the identity of the Glomeraceae isolate applied. N-fixing plants received more protection from fungal pathogens than non-N-fixing dicotyledons; this was attributed to the more intense AM colonization in N-fixing plants. Results have implications for understanding mycorrhizal ecology and agronomic applications.

  17. Trade-Offs in Arbuscular Mycorrhizal Symbiosis: Disease Resistance, Growth Responses and Perspectives for Crop Breeding

    Directory of Open Access Journals (Sweden)

    Catherine N. Jacott

    2017-11-01

    Full Text Available There is an increasing need to develop high-yielding, disease-resistant crops and reduce fertilizer usage. Combining disease resistance with efficient nutrient assimilation through improved associations with symbiotic microorganisms would help to address this. Arbuscular mycorrhizal fungi (AMF form symbiotic relationships with most terrestrial plants, resulting in nutritional benefits and the enhancement of stress tolerance and disease resistance. Despite these advantages, arbuscular mycorrhizal (AM interactions are not normally directly considered in plant breeding. Much of our understanding of the mechanisms of AM symbiosis comes from model plants, which typically exhibit positive growth responses. However, applying this knowledge to crops has not been straightforward. In many crop plants, phosphate uptake and growth responses in AM-colonized plants are variable, with AM plants exhibiting sometimes zero or negative growth responses and lower levels of phosphate acquisition. Host plants must also balance the ability to host AMF with the ability to resist pathogens. Advances in understanding the plant immune system have revealed similarities between pathogen infection and AM colonization that may lead to trade-offs between symbiosis and disease resistance. This review considers the potential trade-offs between AM colonization, agronomic traits and disease resistance and highlights the need for translational research to apply fundamental knowledge to crop improvement.

  18. Rhizobacteria in mycorrhizosphere improved plant health and yield of banana by offering proper nourishment and protection against diseases.

    Science.gov (United States)

    Phirke, Niteen V; Kothari, Raman M; Chincholkar, Sudhir B

    2008-12-01

    The corporate R&D banana orchards of Musa paradisiaca (dwarf Cavendish AAA, var. shrimanti) on a medium black alluvial soil with low nutrients harboured diversified species of vesicular-arbuscular mycorrhizal (VAM) fungi. These fungi infected the roots severely (69.2%), showed elevated (69.8 g(-1) soil) spore density, increased soil bacterial density (245 x 10(8) cfu g(-1)), produced siderophores (58.2%) and reduced nematode population (2.3 g(-1)) in the mycorrhizosphere of plants for integrated plant nutrition management (IPNM) system as compared to traditional treatment of applying chemical fertilisers alone and other test treatments. The interactions of plant roots with native VAM and local and applied rhizobacteria in the matrix of soil conditioner enabled proper nourishment and protection of crop in IPNM treatment as compared to traditional way. Hence, exploitation of plant growth promoting rhizobacteria through judiciously designed IPNM system revealed the (a) relatively increased banana productivity (21.6%, 76 MT ha(-1)), (b) least occurrence of fusarial wilt and negligible evidence of Sigatoka, (c) saving of 50% chemical fertilisers and (d) permitted control over soil fertility in producer's favour over traditional cultivation practices. These findings are discussed in detail.

  19. Arbuscular mycorrhizal fungi and mycorrhizal stimulant affect dry matter and nutrient accumulation in bean and soybean plants

    Directory of Open Access Journals (Sweden)

    Fabrício Henrique Moreira Salgado

    2016-12-01

    Full Text Available The adoption of biological resources in agriculture may allow less dependence and better use of finite resources. This study aimed at evaluating the effects of inoculation with arbuscular mycorrhizal fungi native to the Brazilian Savannah associated with the application of mycorrhizal stimulant (7-hydroxy, 4'-methoxy-isoflavone, in the early growth of common bean and soybean. The experiment was carried out in a greenhouse, in a completely randomized design, with a 7 x 2 factorial arrangement, consisting of five arbuscular mycorrhizal fungi species, joint inoculation (junction of all species in equal proportions and native fungi (without inoculation, in the presence and absence of stimulant. The following traits were evaluated: shoot dry matter, root dry matter, mycorrhizal colonization, nodules dry matter and accumulation of calcium, zinc and phosphorus in the shoot dry matter. The increase provided by the arbuscular mycorrhizal fungi and the use of stimulant reached over 200 % in bean and over 80 % in soybean plants. The fungi Acaulospora scrobiculata, Dentiscutata heterogama, Gigaspora margarita and Rhizophagus clarus, for bean, and Claroideoglomus etunicatum, Dentiscutata heterogama, Rhizophagus clarus and the joint inoculation, for soybean, increased the dry matter and nutrients accumulation.

  20. Signaling in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Harrison, Maria J

    2005-01-01

    Many microorganisms form symbioses with plants that range, on a continuous scale, from parasitic to mutualistic. Among these, the most widespread mutualistic symbiosis is the arbuscular mycorrhiza, formed between arbuscular mycorrhizal (AM) fungi and vascular flowering plants. These associations occur in terrestrial ecosystems throughout the world and have a global impact on plant phosphorus nutrition. The arbuscular mycorrhiza is an endosymbiosis in which the fungus inhabits the root cortical cells and obtains carbon provided by the plant while it transfers mineral nutrients from the soil to the cortical cells. Development of the symbiosis involves the differentiation of both symbionts to create novel symbiotic interfaces within the root cells. The aim of this review is to explore the current understanding of the signals and signaling pathways used by the symbionts for the development of the AM symbiosis. Although the signal molecules used for initial communication are not yet known, recent studies point to their existence. Within the plant, there is evidence of arbuscular mycorrhiza-specific signals and of systemic signaling that influences phosphate-starvation responses and root development. The landmark cloning of three plant signaling proteins required for the development of the symbiosis has provided the first insights into a signaling pathway that is used by AM fungi and by rhizobia for their symbiotic associations with legumes.

  1. Arbuscular mycorrhizal fungi decrease radiocesium accumulation in Medicago truncatula

    Energy Technology Data Exchange (ETDEWEB)

    Gyuricza, Veronika; Declerck, Stephane [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Dupre de Boulois, Herve, E-mail: herve.dupre@uclouvain.b [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)

    2010-08-15

    The role of arbuscular mycorrhizal fungi (AMF) in plant radiocesium uptake and accumulation remains ambiguous. This is probably due to the presence of other soil microorganisms, the variability of soil characteristics and plant nutritional status or the availability of its chemical analogue, potassium (K). Here, we used an in vitro culture system to study the impact of increased concentration of K on radiocesium accumulation in non K-starved mycorrhizal and non-mycorrhizal Medicago truncatula plants. In the presence of AMF radiocesium uptake decreased regardless of the concentration of K, and its translocation from root to shoot was also significantly lower. Potassium also reduced the accumulation of radiocesium in plants but to a lesser extent than mycorrhization, and without any effect on translocation. These results suggest that AMF in combination with K can play a key role in reducing radiocesium uptake and its subsequent translocation to plant shoots, thereby representing good potential for improved phytomanagement of contaminated areas.

  2. Ceratobasidiaceae mycorrhizal fungi isolated from nonphotosynthetic orchid Chamaegastrodia sikokiana.

    Science.gov (United States)

    Yagame, Takahiro; Yamato, Masahide; Suzuki, Akira; Iwase, Koji

    2008-02-01

    Mycorrhizal fungi were isolated from the nonphotosynthetic orchid Chamaegastrodia sikokiana and identified as members of Ceratobasidiaceae by phylogenetic analysis of the internal transcribed spacer (ITS) region of ribosomal deoxyribonucleic acid. The ITS sequences were similar among geographically separated samples obtained from Mt. Kiyosumi in Chiba Prefecture and Mt. Yokokura in Kochi Prefecture. One of the isolated fungi, KI1-2, formed ectomycorrhiza on seedlings of Abies firma in pot culture, suggesting that tripartite symbiosis exists among C. sikokiana, mycorrhizal fungi, and A. firma in nature, and carbon compounds are supplied from A. firma to C. sikokiana through the hyphae of the mycorrhizal fungi. To our knowledge, this is the second study to suggest the involvement of Ceratobasidiaceae fungi in tripartite symbiosis with achlorophyllous orchids and photosynthetic host plants.

  3. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization Efecto de la infestación con micorrizas vesiculo arbusculares (VAM en plantas de Zea mays fertilizadas con dosis bajas de fósforo

    Directory of Open Access Journals (Sweden)

    Amitava Rakshit

    2010-01-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.En condiciones de casa de malla se evaluó el efecto de la infestación con micorrizas vesículo arbusculares (VAM en la asimilación de P por plantas de maíz (Zea mays, cv.DDH hybrid cultivadas en un Oxisol. Como micorriza se utilizó el hongo Glomus mosseae. En ambos tratamientos (con micorriza y sin ella se aplicó fosfato ferroso (FePO4.4H2O. La producción de MS de maíz fue mayor cuando se aplicaron el hongo + la fuente de P. La cantidad de P en el suelo con este tratamiento fue menor que en el suelo fertilizado pero sin aplicación del hongo. En las hojas de las plantas las mayores concentraciones de P se observaron igualmente en el tratamiento micorriza + aplicación de fertilizante.

  4. Alleviation of drought stress of marigold (Tagetes erecta) plants by using arbuscular mycorrhizal fungi

    Science.gov (United States)

    Asrar, Abdul-Wasea A.; Elhindi, Khalid M.

    2010-01-01

    The effect of an arbuscular mycorrhizal fungus “AMF” (Glomus constrictum Trappe) on growth, pigments, and phosphorous content of marigold (Tagetes erecta) plant grown under different levels of drought stress was investigated. The applied drought stress levels reduced growth vigor (i.e. plant height, shoot dry weight, flower diameter as well as its fresh and dry weights) of mycorrhizal and non-mycorrhizal plant as compared to control plant (non-drought stressed plant). The presence of mycorrhizal fungus, however, stimulated all growth parameters of the treated plant comparing to non-mycorrhizal treated plant. The photosynthetic pigments (carotene in flowers and chlorophylls a and b in leaves) were also stimulated by the mycorrhizal fungi of well-watered as well as of water-stressed plants. The total pigments of mycorrhizal plants grown under well-watered conditions were higher than those of non-mycorrhizal ones by 60%. In most cases, drought-stressed mycorrhizal plants were significantly better than those of the non-mycorrhizal plants. So, the overall results suggest that mycorrhizal fungal colonization affects host plant positively on growth, pigments, and phosphorous content, flower quality and thereby alleviates the stress imposed by water with holding. PMID:23961109

  5. Utilisation of carbon substrates by orchid and ericoid mycorrhizal fungi from Australian dry sclerophyll forests.

    Science.gov (United States)

    Midgley, David J; Jordan, Lyndon A; Saleeba, Jennifer A; McGee, Peter A

    2006-05-01

    The utilisation of a range of cell-wall-related and aromatic carbon substrates by multiple genotypes of three ericoid mycorrhizal fungal taxa was compared with two orchid mycorrhizal fungal taxa. Both groups of fungi catabolised most common substrates, though significant inter- and intraspecific variability was observed in the use of a few carbon substrates. Orchid mycorrhizal fungi had limited access to tannic acid as a carbon source and did not use phenylalanine, while the ericoid mycorrhizal fungi used both. Utilisation of tryptophan was limited to single genotypes of each of the orchid mycorrhizal fungi, and to only two of the three ericoid mycorrhizal fungi examined. Although broadly similar, some significant differences apparently exist in carbon catabolism of ericoid and orchid mycorrhizal fungi from the same habitat. Functional and ecological implications of these observations are discussed.

  6. P depletion and activity of phosphatases in the rhizosphere of mycorrhizal and non-mycorrhizal cucumber (Cucumis Sativus L.)

    DEFF Research Database (Denmark)

    Joner, E.J.; Magid, J.; Gahoonia, T.S.

    1995-01-01

    was sectioned in a freezing microtome and analyzed for extracellular acid (pH 5.2) and alkaline (pH 8.5) phosphatase activity as well as depletion of NaHCO-3-extractable inorganic P (P-i) and P-o. Roots and mycorrhizal hyphae depleted the soil of P-i but did not influence the concentration of P-o in spite...... of increased phosphatase activity in soil influenced by roots. Phosphatase activity at both pH values was highest in soil influenced by uncolonized roots, but this was attributed to higher root length densities as compared to mycorrhizal roots. Mycorrhizal hyphae showed no influence on soil phosphatase...... activity in spite of high hyphal length densities ( gt 22 m cm-3). Hyphae were also able to deplete soil of P-i beyond the membrane interface....

  7. Common mycorrhizal networks and their effect on the bargaining power of the fungal partner in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Bücking, Heike; Mensah, Jerry A; Fellbaum, Carl R

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi form mutualistic interactions with the majority of land plants, including some of the most important crop species. The fungus takes up nutrients from the soil, and transfers these nutrients to the mycorrhizal interface in the root, where these nutrients are exchanged against carbon from the host. AM fungi form extensive hyphal networks in the soil and connect with their network multiple host plants. These common mycorrhizal networks (CMNs) play a critical role in the long-distance transport of nutrients through soil ecosystems and allow the exchange of signals between the interconnected plants. CMNs affect the survival, fitness, and competitiveness of the fungal and plant species that interact via these networks, but how the resource transport within these CMNs is controlled is largely unknown. We discuss the significance of CMNs for plant communities and for the bargaining power of the fungal partner in the AM symbiosis.

  8. Life histories of symbiotic rhizobia and mycorrhizal fungi. Review.

    NARCIS (Netherlands)

    Denison, R.F.; Kiers, E.T.

    2011-01-01

    Research on life history strategies of microbial symbionts is key to understanding the evolution of cooperation with hosts, but also their survival between hosts. Rhizobia are soil bacteria known for fixing nitrogen inside legume root nodules. Arbuscular mycorrhizal (AM) fungi are ubiquitous root

  9. (Vigna radiata L.) with arbuscular mycorrhizal fungi a

    African Journals Online (AJOL)

    Jane

    2011-07-25

    Jul 25, 2011 ... cultivar, rhizobial strains, and environmental conditions. (Giller, 2001). Mungbean can also establish symbiosis with arbuscular mycorrhizal fungi (AMF) (Clarkson, 1985; ..... Planta, 201: 463-469. Drevon JJ, Heckmann MO, Soussana JF, Salsac L (1988). Inhibition of nitrogen fixation by nitrate assimilation in ...

  10. Mycorrhizal association in soybean and weeds in competition

    Directory of Open Access Journals (Sweden)

    Cíntia Maria Teixeira Fialho

    2016-04-01

    Full Text Available The purpose of this study was to evaluate the effects of mycorrhizal association on the interference of Bidens pilosa, Urochloa decumbens and Eleusine indica on soybean culture in two conditions: a plants competing without contact with roots of another species; b with contact between roots. At 60 days after planting, growth, nutrient accumulation and mycorrhizal colonization of soybean and weeds were evaluated. The contact between roots of soybean plant and weed species increased the negative interference effects for both species, with less growth and nutrient accumulation. With the individualization of roots, higher competition occurred for soil resources up to 60 days of coexistence between species. In competition with soybean, Bidens pilosa and Urochloa decumbens stood out in accumulation of most nutrients without differing from when cultivated in monocultivation. The increase of the soybean mycorrhizal colonization was 53, 40 and 33% when in competition with Urochloa decumbens, Eleusine indica and Bidens pilosa species, respectively. A positive interaction occurred for soybean mycorrhizal colonization and competing plants irrespective of weed species or root contact.

  11. Siderophore production by mycorrhizal sorghum roots under micronutrient deficient condition

    Directory of Open Access Journals (Sweden)

    N. Aliasgharzad

    2009-05-01

    Full Text Available It has widely been accepted that mycorrhizal symbiosis improves micronutrients uptake by most of the plants. In this study, sorghum (Sorghum bicolor L. plants were grown in sterile perlite and were inoculated with either Glomus etunicatum (GE or G.intraradices (GI, while the control set was left un-inoculated. Rorison's nutrient solution with three levels of 0, half and full strength (C0, C0.5 and C1, respectively of Fe, Cu, Zn and Mn was applied to the pots during 85 days of growth period. Chrome azurol-S assay was used for determination of siderophores in root leachates on 45, 65 and 85 days after sowing (DAS. Siderophore production per unit volume of root was higher in mycorrhizal than non-mycorrhizal plants. Both GE and GI were efficient fungi in this respect. Siderophore production was significantly induced at C0 level of the micronutrients. Amount of siderophores produced on 45 and 85 DAS was more than 65 DAS. Mycorrhizal root colonization by GE or GI was not significantly affected by micronutrient levels.

  12. In vitro culture of arbuscular mycorrhizal fungi: advances and future ...

    African Journals Online (AJOL)

    Arbuscular mycorrhizal (AM) fungi are ecologically important for most vascular plants for their growth and survival. AM fungi are obligate symbionts. In recent years, there have been many attempts to cultivate in vitro. Some relevant results indicate efforts are not far from successful growth of AM fungi independent of a plant ...

  13. A biological market analysis of the plant-mycorrhizal symbiosis

    NARCIS (Netherlands)

    Wyatt, G.A.K.; Kiers, E.T.; Gardner, A.; West, S.A.

    2014-01-01

    It has been argued that cooperative behavior in the plant-mycorrhizal mutualism resembles trade in a market economy and can be understood using economic tools. Here, we assess the validity of this "biological market" analogy by investigating whether a market mechanism-that is, competition between

  14. In vitro culture of arbuscular mycorrhizal fungi: advances and future ...

    African Journals Online (AJOL)

    Admin

    This paper describes the methods to cultivate root organs, and to select and purify AM fungal inocula (intraradical ... Key words: Arbuscular mycorrhizal fungi, continuous culture, root organ cultures, intraradical and extraradical forms, in vitro. .... Although in vitro culture is an artificial system, it may be a valuable tool to study ...

  15. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    FAMA

    2015-09-30

    Sep 30, 2015 ... architecture and low root hair density (warm season C4 grasses), derive the greater growth benefits from AMF ... fine root architecture is considered as an alternative to mycorrhizae in P-limited soils. ..... L. to mycorrhizal fungi, phosphorus and soil organic matter: implications for reclamation. J. Appl. Ecol.

  16. Mycorrhizal specificity in the fully mycoheterotrophic Hexalectris Raf. (Orchidaceae: Epidendroideae)

    Science.gov (United States)

    Aaron H. Kennedy; D. Lee Taylor; Linda E. Watson

    2011-01-01

    Mycoheterotrophic species have abandoned an autotrophic lifestyle and obtain carbon exclusively from mycorrhizal fungi. Although these species have evolved independently in many plant families, such events have occurred most often in the Orchidaceae, resulting in the highest concentration of these species in the tracheophytes. Studies of mycoheterotrophic species...

  17. Do chlorophyllous orchids heterotrophically use mycorrhizal fungal carbon?

    Science.gov (United States)

    Selosse, Marc-André; Martos, Florent

    2014-11-01

    The roots of orchids associate with mycorrhizal fungi, the rhizoctonias, which are considered to exchange mineral nutrients against plant carbon. The recent discovery that rhizoctonias grow endophytically in non-orchid plants raises the possibility that they provide carbon to orchids, explaining why some orchids differ in isotopic abundances from autotrophic plants.

  18. Mycorrhizal status and AMF community structure of fruit crops from ...

    African Journals Online (AJOL)

    Arbuscular mycorrhizal fungi (AMF) association of Mangifera indica (mango), Musa acuminate (banana), Carica papaya (papaya), Citrus limon (lemon), Persea americana (avocado), and Psidium guajava (guava) was investigated from a lowland area of Showa Robit. Percentage of root colonization, spore abundance, ...

  19. Arbuscular mycorrhizal fungi in alleviation of salt stress: a review.

    Science.gov (United States)

    Evelin, Heikham; Kapoor, Rupam; Giri, Bhoopander

    2009-12-01

    Salt stress has become a major threat to plant growth and productivity. Arbuscular mycorrhizal fungi colonize plant root systems and modulate plant growth in various ways. This review addresses the significance of arbuscular mycorrhiza in alleviation of salt stress and their beneficial effects on plant growth and productivity. It also focuses on recent progress in unravelling biochemical, physiological and molecular mechanisms in mycorrhizal plants to alleviate salt stress. The role of arbuscular mycorrhizal fungi in alleviating salt stress is well documented. This paper reviews the mechanisms arbuscular mycorrhizal fungi employ to enhance the salt tolerance of host plants such as enhanced nutrient acquisition (P, N, Mg and Ca), maintenance of the K(+) : Na(+) ratio, biochemical changes (accumulation of proline, betaines, polyamines, carbohydrates and antioxidants), physiological changes (photosynthetic efficiency, relative permeability, water status, abscissic acid accumulation, nodulation and nitrogen fixation), molecular changes (the expression of genes: PIP, Na(+)/H(+) antiporters, Lsnced, Lslea and LsP5CS) and ultra-structural changes. Theis review identifies certain lesser explored areas such as molecular and ultra-structural changes where further research is needed for better understanding of symbiosis with reference to salt stress for optimum usage of this technology in the field on a large scale. This review paper gives useful benchmark information for the development and prioritization of future research programmes.

  20. Effect of mycorrhizal inoculum and urea fertilizer on diseases ...

    African Journals Online (AJOL)

    A randomized block design with four replicates was used, with two applications of mycorrhizal inoculum. The inoculum contained spores of Glomus sp. and Gigaspora sp. in concentration of 2.103 spores.g-¹. A urea treatment and an absolute control were also used. The number of nodules per plant, the root colonization rate ...

  1. Arsenic uptake and phytoremediation potential by arbuscular mycorrhizal fungi

    Science.gov (United States)

    Xinhua He; Erik Lilleskov

    2014-01-01

    Arsenic (As) contamination of soils and water is a global problem because of its impacts on ecosystems and human health. Various approaches have been attempted for As remediation, with limited success. Arbuscular mycorrhizal (AM) fungi play vital roles in the uptake of water and essential nutrients, especially phosphorus (P), and hence enhance plant performance and...

  2. Interactive effects of Arbuscular mycorrhizal fungi and rhizobial ...

    African Journals Online (AJOL)

    Legumes form a tripartite symbiosis with Arbuscular mycorrhizal fungi (AMF) and rhizobia. Chickpea plants were inoculated with six strains of Mesorhizobium ciceri and three AMF species, Glomus intraradices (GI), G. mosseae (GM) and G. etunicatum (GE). The plants inoculated with a number of AMF species and bacterial ...

  3. Cropping enhances mycorrhizal benefits to maize in a tropical soil

    Czech Academy of Sciences Publication Activity Database

    Jemo, M.; Souleymanou, A.; Frossard, E.; Jansa, Jan

    2014-01-01

    Roč. 79, č. 2014 (2014), s. 117-124 ISSN 0038-0717 R&D Projects: GA MŠk(CZ) LK11224; GA ČR GAP504/12/1665 Institutional support: RVO:61388971 Keywords : tropical soil * mycorrhizal benefits * southern Cameroon Subject RIV: EE - Microbiology, Virology Impact factor: 3.932, year: 2014

  4. Mycorrhizal status of Lycium europaeum in the coastal dunes of ...

    African Journals Online (AJOL)

    SARAH

    2013-11-30

    Nov 30, 2013 ... of L. europaeum and determines its presence in different regions of Morocco. The role of mycorrhizal fungi in the growth and the nutrition of plants have been amply demonstrated by. Chaussod and Nouaim (1996). For example, arbuscular mycorrhizae, improve the ability of the plant nutrition, including ...

  5. Shoot- and root-borne cytokinin influences arbuscular mycorrhizal symbiosis

    NARCIS (Netherlands)

    Rebeca Cosme, M.P.

    2016-01-01

    The arbuscular mycorrhizal (AM) symbiosis is functionally important for the nutrition and growth of most terrestrial plants. Nearly all phytohormones are employed by plants to regulate the symbiosis with AM fungi, but the regulatory role of cytokinin (CK) is not well understood. Here, we used

  6. Diversity of arbuscular mycorrhizal fungi in the rhizosphere of Coffea ...

    African Journals Online (AJOL)

    SARAH

    2013-04-25

    Apr 25, 2013 ... symbiosis to plant drought tolerance is the result of accumulative physical, nutritional, physiological and cellular effects. Mycorrhizal fungi, which are active in the rhizosphere, take part in the cycles and transfer of mineral elements in the soil and into the roots (George et al., 1992). Some minerals such as ...

  7. Phosphorus and nitrogen regulate arbuscular mycorrhizal symbiosis in Petunia hybrida.

    Directory of Open Access Journals (Sweden)

    Eva Nouri

    Full Text Available Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis, the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi.

  8. Contribution of arbuscular mycorrhizal fungi to pearl millet ...

    African Journals Online (AJOL)

    Land degradation may cause nutrient deficiencies for plant growth. These deficiencies can be partly compensated through plant association with arbuscular mycorrhizal (AM) fungi under the condition that the degradation status does not affect the symbiosis. We therefore investigated P and K uptake by millet [Pennisetum ...

  9. Mycorrhizal status of Olea europaea spp. oleaster in Morocco

    African Journals Online (AJOL)

    SARAH

    2013-01-31

    Jan 31, 2013 ... rhizosphere of the oleaster trees, revealed the presence of five fungus species: Glomus intraradices, ... Mycorrhizal fungi are an essential link between soil and plants. They play an important role in the dynamic of the ecosystem (Bever et al., 1997, van ... plants by providing a particular mineral nutrition.

  10. Arbuscular mycorrhizal fungi improve the growth of olive trees and ...

    African Journals Online (AJOL)

    Arbuscular mycorrhizal fungi improve the growth of olive trees and their resistance to transplantation stress. ... This change in the root: shoot ratio permitted greater utilization of soil resources and strengthened the plant's capacity to resist transplantation shock and water stress. The abundance of the two fungi in the roots of ...

  11. Solanum cultivar responses to arbuscular mycorrhizal fungi: growth ...

    African Journals Online (AJOL)

    A greenhouse experiment was carried out in a sandy soil with a low available phosphorus to evaluate responsiveness of four Solanum aethiopicum cultivars to indigenous arbuscular mycorrhizal fungi. Results showed clear interaction between genetic variability of cultivars and fungal isolates on shoot biomass and on ...

  12. The effects of arbuscular mycorrhizal fungi and phosphorus levels ...

    African Journals Online (AJOL)

    user

    2015-01-21

    Jan 21, 2015 ... To evaluate the effect of arbuscular mycorrhizal fungi and phosphorus levels on root traits of cucumber plants, a factorial experiment was carried out based on a randomized completely design pot culture. Four phosphorus fertilization treatments, including 2, 5, 10 and 15 mg P kg-1 soil possessed ...

  13. Effects of arbuscular mycorrhizal fungi on resistance to Phytophthora ...

    African Journals Online (AJOL)

    Thai honey tangerine (Sainamphueng tangerine) is generally grown by grafting on rootstocks of another variety of tangerine or citrus species which may differ in their reaction to beneficial and pathogenic soil organisms. The objectives of this study were to evaluate responses to arbuscular mycorrhizal (AM) fungi and ...

  14. Growth and mineral nutrition responses of mycorrhizal and non ...

    African Journals Online (AJOL)

    The effects of a superphosphate (SP) and a rock phosphate (RP), with equal total P contents, on the growth and mineral nutrition responses of mycorrhizal and nonmycorrhizal cowpea, pigeon pea and groundnut were investigated in a pot experiment using an air-dry gamma ray-sterilized (1.5Mrad) Andisol subsoil.

  15. Growth and development of symbiotic Arbuscular mycorrhizal fungi ...

    African Journals Online (AJOL)

    Herbicides are applied to control weeds in agricultural practices and could also be detrimental to the development of some microorganisms living in the soil ecosystem. This study was conducted to determine the growth and development of mycorrhizal fungi, Glomus mossea (Nicol. and Gerd.), in soils treated with herbicides ...

  16. Influence of mycorrhizal inoculation on alley cropped farms in a ...

    African Journals Online (AJOL)

    The use of Arbuscular mycorrhizal (AM) fungi under farmers' conditions was tried at Ajibode Village, a humid tropical environment on maize/cassava intercropped farms in an alley cropping system. Four species of AM fungi (Glomus clarum, Glomus mosseae Glomus etunicatum and Acaulospora dilatata) were used in ...

  17. Arbuscular mycorrhizal fungi species associated with rhizosphere of ...

    African Journals Online (AJOL)

    A survey of arbuscular mycorrhizal fungi (AMF) diversity and date palm (Phoenix dactylifera L.) tree root colonization in arid areas was undertaken in ten palm groves located along the Ziz valley (Tafilalet, south-west Morocco). The frequency and the mean intensity of root colonization reached 72 and 43% respectively and ...

  18. Arbuscular-mycorrhizal fungi (Glomales) in Egypt. III: Distribution ...

    African Journals Online (AJOL)

    Roots and rhizospheric soils of 26 plant species belonging to 18 families representing five different habitats at El-Omayed Biosphere Reserve were collected and examined for arbuscular-mycorrhizal fungal (AMF) associations. Plant species recorded in the habitat of coastal sand dunes had the highest percentage of ...

  19. Phosphorus and nitrogen regulate arbuscular mycorrhizal symbiosis in Petunia hybrida.

    Science.gov (United States)

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi.

  20. Transgenerational effects of plant sex and arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Varga, Sandra; Vega-Frutis, Rocío; Kytöviita, Minna-Maarit

    2013-08-01

    In gynodioecious plants, females are predicted to produce more and/or better offspring than hermaphrodites in order to be maintained in the same population. In the field, the roots of both sexes are usually colonized by arbuscular mycorrhizal (AM) fungi. Transgenerational effects of mycorrhizal symbiosis are largely unknown, although theoretically expected. We examined the maternal and paternal effects of AM fungal symbiosis and host sex on seed production and posterior seedling performance in Geranium sylvaticum, a gynodioecious plant. We hand-pollinated cloned females and hermaphrodites in symbiosis with AM fungi or in nonmycorrhizal conditions and measured seed number and mass, and seedling survival and growth in a glasshouse experiment. Females produced more seeds than hermaphrodites, but the seeds did not germinate, survive or grow better. Mycorrhizal plants were larger, but did not produce more seeds than nonmycorrhizal plants. Transgenerational parental effects of AM fungi were verified in seedling performance. This is the first study to show transgenerational mycorrhiza-mediated parental effects in a gynodioecious species. Mycorrhizal symbiosis affects plant fitness mainly through female functions with enduring effects on the next generation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  1. Infection

    African Journals Online (AJOL)

    from the neonatal period to school age.' In Saudi Arabia, the rate of 5.3 per cent was reported' while in Nigeria,. Okafor et a1,7 found the prevalence rate .... the multiplication of the organisms in the urine, resulting in lalse diagnosis of urinary tract infection. This over-diagnosis ofl ITI may account for the high prevalence rate ...

  2. Phenanthrene uptake by Medicago sativa L. under the influence of an arbuscular mycorrhizal fungus

    Energy Technology Data Exchange (ETDEWEB)

    Wu Naiying [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Department of Chemistry, Shangqiu Normal College, Shangqiu 476000 (China); Huang Honglin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhang Shuzhen, E-mail: szzhang@rcees.ac.c [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhu Yongguan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Christie, Peter [Agri-Environment Branch, Agriculture Food and Environmental Science Division, Agri-Food and Biosciences Institute, Newforge Lane, Belfast BT9 5PX (United Kingdom); Zhang Yong [State Key Laboratory of Marine Environmental Science, Environmental Science Research Centre, Xiamen University, Xiamen 361005 (China)

    2009-05-15

    Phenanthrene uptake by Medicago sativa L. was investigated under the influence of an arbuscular mycorrhizal fungus. Inoculation of lucerne with the arbuscular mycorrhizal fungus Glomus etunicatum L. resulted in higher phenanthrene accumulation in the roots and lower accumulation in the shoots compared to non-mycorrhizal controls. Studies on sorption and desorption of phenanthrene by roots and characterization of heterogeneity of mycorrhizal and non-mycorrhizal roots using solid-state {sup 13}C nuclear magnetic resonance spectroscopy ({sup 13}C NMR) demonstrated that increased aromatic components due to mycorrhizal inoculation resulted in enhanced phenanthrene uptake by the roots but lower translocation to the shoots. Direct visualization using two-photon excitation microscopy (TPEM) revealed higher phenanthrene accumulation in epidermal cells of roots and lower transport into the root interior and stem in mycorrhizal plants than in non-mycorrhizal controls. These results provide some insight into the mechanisms by which arbuscular mycorrhizal inoculation may influence the uptake of organic contaminants by plants. - Colonization by an arbuscular mycorrhizal fungus promoted root uptake and decreased shoot uptake of phenanthrene by Medicago sativa L.

  3. Plant mycorrhizal traits in Europe in relation to climatic and edaphic gradients

    Science.gov (United States)

    Guillermo Bueno, C.; Gerz, Maret; Zobel, Martin; Moora, Mari

    2017-04-01

    Around 90% of plant species associate with mycorrhizal fungi. The symbiosis is known to provide plants with soil N, P and water, and fungi with plant photosynthesized carbohydrates. However, not all mycorrhizal symbioses are identical. The identity of associated plant and fungal species differs, as does the effect of the symbiosis on nutrient cycling and ecosystems more generally. In this study, we analysed the European distribution of two plant mycorrhizal traits in relation to climatic and edaphic drivers. We used the European distribution of the frequency of mycorrhizal colonization (plant mycorrhizal status); whether mycorrhizal fungi either always (obligately mycorrhizal, OM), or sometimes (facultatively mycorrhizal, FM) colonize plant roots, and the four main plant mycorrhizal types; arbuscular (AM), ecto-(ECM), ericoid (ERM), and non-mycorrhizal (NM) plants. We expected AM species to predominate in ecosystems where most soil nutrients occur in inorganic forms (lower latitudes) and those with higher soil pH. By contrast, due to the saprophytic abilities of ECM and ERM fungi, we expected ECM and ERM plants to predominate in ecosystems where nutrients are bound to organic compounds (higher latitudes) and those with lower soil pH. NM plant species are known to be common in disturbed habitats or in extremely phosphorus poor ecosystems, such as the Arctic tundra. Our results showed that the distribution of mycorrhizal types was driven by temperature and soil pH, with increases of NM, ECM and ERM, and decreases of AM, with latitude. FM predominated over OM species and this difference increased with latitude and was dependent on temperature drivers only. These results represent the first evidence at a European scale of plant mycorrhizal distribution patterns linked with climatic and edaphic gradients, supporting the idea of a tight relationship between the mycorrhizal symbiosis and nutrient cycling.

  4. Untangling above- and belowground mycorrhizal fungal networks in tropical orchids.

    Science.gov (United States)

    Leake, J R; Cameron, D D

    2012-10-01

    Orchids typically depend on fungi for establishment from seeds, forming mycorrhizal associations with basidiomycete fungal partners in the polyphyletic group rhizoctonia from early stages of germination, sometimes with very high specificity. This has raised important questions about the roles of plant and fungal phylogenetics, and their habitat preferences, in controlling which fungi associate with which plants. In this issue of Molecular Ecology, Martos et al. (2012) report the largest network analysis to date for orchids and their mycorrhizal fungi, sampling a total of over 450 plants from nearly half the 150 tropical orchid species on Reunion Island, encompassing its main terrestrial and epiphytic orchid genera. The authors found a total of 95 operational taxonomic units of mycorrhizal fungi and investigated the architecture and nestedness of their bipartite networks with 73 orchid species. The most striking finding was a major ecological barrier between above- and belowground mycorrhizal fungal networks, despite both epiphytic and terrestrial orchids often associating with closely related taxa across all three major lineages of rhizoctonia fungi. The fungal partnerships of the epiphytes and terrestrial species involved a diversity of fungal taxa in a modular network architecture, with only about one in ten mycorrhizal fungi partnering orchids in both groups. In contrast, plant and fungal phylogenetics had weak or no effects on the network. This highlights the power of recently developed ecological network analyses to give new insights into controls on plant-fungal symbioses and raises exciting new hypotheses about the differences in properties and functioning of mycorrhiza in epiphytic and terrestrial orchids. © 2012 Blackwell Publishing Ltd.

  5. Infection,

    Science.gov (United States)

    1980-10-16

    lost by diuresis in early convalescence (1). Severe retention of body water, especially during central nervous system infection, has now been widely...adrenocortical production of glucocorticoid and ketosteroid hormones often declines into a subnormal range. The labile pool of body nitrogen is...may not become apparent until early convalescence when postfebrile diuresis causes excessive fluid to be excreted. (3) Protein requirements ’- Despite

  6. Response of Mycorrhizal Diversity to Current Climatic Changes

    Directory of Open Access Journals (Sweden)

    Stephen E. Williams

    2011-01-01

    Full Text Available Form and function of mycorrhizas as well as tracing the presence of the mycorrhizal fungi through the geological time scale are herein first addressed. Then mycorrhizas and plant fitness, succession, mycorrhizas and ecosystem function, and mycorrhizal resiliency are introduced. From this, four hypotheses are drawn: (1 mycorrhizal diversity evolved in response to changes in Global Climate Change (GCC environmental drivers, (2 mycorrhizal diversity will be modified by present changes in GCC environmental drivers, (3 mycorrhizal changes in response to ecological drivers of GCC will in turn modify plant, community, and ecosystem responses to the same, and (4 Mycorrhizas will continue to evolve in response to present and future changes in GCC factors. The drivers of climate change examined here are: CO2 enrichment, temperature rise, altered precipitation, increased N-deposition, habitat fragmentation, and biotic invasion increase. These impact the soil-rhizosphere, plant and fungal physiology and/or ecosystem(s directly and indirectly. Direct effects include changes in resource availability and change in distribution of mycorrhizas. Indirect effects include changes in below ground allocation of C to roots and changes in plant species distribution. GCC ecological drivers have been partitioned into four putative time frames: (1 Immediate (1–2 years impacts, associated with ecosystem fragmentation and habitat loss realized through loss of plant-hosts and disturbance of the soil; (2 Short-term (3–10 year impacts, resultant of biotic invasions of exotic mycorrhizal fungi, plants and pests, diseases and other abiotic perturbations; (3 Intermediate-term (11–20 year impacts, of cumulative and additive effects of increased N (and S deposition, soil acidification and other pollutants; and (4 Long-term (21–50+ year impacts, where increased temperatures and CO2 will destabilize global rainfall patterns, soil properties and plant ecosystem resilience. Due

  7. Effect of Arbuscular Mycorrhizal Fungi on Chemical Constituents in Cotton/Alfalfa Mixed Culture

    OpenAIRE

    Ibrahim Mazen

    2017-01-01

    A pot experiment was conducted to study the extent of changes occurring in the nutrients, chlorophyll and protein of plants grown in cotton/alfalfa mixed culture as affected by inoculation with indigenous arbuscular mycorrhizal fungi (AMF). The experiment consisted of mycorrhizal treatments (with and without AMF inoculation) and three planting patterns (cotton monoculture, alfalfa monoculture, cotton/alfalfa mixed culture). Arbuscular mycorrhizal (AM) inoculum previously isolated from a rhizo...

  8. Duration and intensity of shade differentially affects mycorrhizal growth- and phosphorus uptake responses of Medicago truncatula

    Science.gov (United States)

    Konvalinková, Tereza; Püschel, David; Janoušková, Martina; Gryndler, Milan; Jansa, Jan

    2015-01-01

    Plant and fungal partners in arbuscular mycorrhizal symbiosis trade mineral nutrients for carbon, with the outcome of this relationship for plant growth and nutrition being highly context-dependent and changing with the availability of resources as well as with the specific requirements of the different partners. Here we studied how the model legume Medicago truncatula, inoculated or not with a mycorrhizal fungus Rhizophagus irregularis, responded to a gradient of light intensities applied over different periods of time, in terms of growth, phosphorus nutrition and the levels of root colonization by the mycorrhizal fungus. Short-term (6 d) shading, depending on its intensity, resulted in a rapid decline of phosphorus uptake to the shoots of mycorrhizal plants and simultaneous accumulation of phosphorus in the roots (most likely in the fungal tissues), as compared to the non-mycorrhizal controls. There was, however, no significant change in the levels of mycorrhizal colonization of roots due to short-term shading. Long-term (38 d) shading, depending on its intensity, provoked a multitude of plant compensatory mechanisms, which were further boosted by the mycorrhizal symbiosis. Mycorrhizal growth- and phosphorus uptake benefits, however, vanished at 10% of the full light intensity applied over a long-term. Levels of root colonization by the mycorrhizal fungus were significantly reduced by long-term shading. Our results indicate that even short periods of shade could have important consequences for the functioning of mycorrhizal symbiosis in terms of phosphorus transfer between the fungus and the plants, without any apparent changes in root colonization parameters or mycorrhizal growth response, and call for more focused research on temporal dynamics of mycorrhizal functioning under changing environmental conditions. PMID:25763002

  9. Mycorrhizal symbiosis and local adaptation in Aster amellus: a field transplant experiment.

    Science.gov (United States)

    Pánková, Hana; Raabová, Jana; Münzbergová, Zuzana

    2014-01-01

    Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies

  10. Mycorrhizal symbiosis and local adaptation in Aster amellus: a field transplant experiment.

    Directory of Open Access Journals (Sweden)

    Hana Pánková

    Full Text Available Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K and Ceske Stredohori (region S. Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local

  11. Mycorrhizal Fungal Diversity and Community Composition in Two Closely Related Platanthera (Orchidaceae) Species.

    Science.gov (United States)

    Esposito, Fabiana; Jacquemyn, Hans; Waud, Michael; Tyteca, Daniel

    2016-01-01

    While it is generally acknowledged that orchid species rely on mycorrhizal fungi for completion of their life cycle, little is yet known about how mycorrhizal fungal diversity and community composition vary within and between closely related orchid taxa. In this study, we used 454 amplicon pyrosequencing to investigate variation in mycorrhizal communities between pure (allopatric) and mixed (sympatric) populations of two closely related Platanthera species (Platanthera bifolia and P. chlorantha) and putative hybrids. Consistent with previous research, the two species primarily associated primarily with members of the Ceratobasidiaceae and, to a lesser extent, with members of the Sebacinales and Tulasnellaceae. In addition, a large number of ectomycorrhizal fungi belonging to various families were observed. Although a considerable number of mycorrhizal fungi were common to both species, the fungal communities were significantly different between the two species. Individuals with intermediate morphology showed communities similar to P. bifolia, confirming previous results based on the genetic architecture and fragrance composition that putative hybrids essentially belonged to one of the parental species (P. bifolia). Differences in mycorrhizal communities between species were smaller in mixed populations than between pure populations, suggesting that variation in mycorrhizal communities was largely controlled by local environmental conditions. The small differences in mycorrhizal communities in mixed populations suggests that mycorrhizal fungi are most likely not directly involved in maintaining species boundaries between the two Platanthera species. However, seed germination experiments are needed to unambiguously assess the contribution of mycorrhizal divergence to reproductive isolation.

  12. On the perils of mycorrhizal status lists: the case of Buddleja davidii.

    Science.gov (United States)

    Dickie, I A; Thomas, M M; Bellingham, P J

    2007-11-01

    One observation in a mycorrhizal check-list that Buddleja davidii is nonmycorrhizal has been perpetuated in subsequent citations and used in a number of analyses of mycorrhizal ecology and evolution. Direct observation of B. davidii from New Zealand and the UK shows extensive arbuscular mycorrhizal fungal structures inside B. davidii roots. The suggestion that B. davidii is nonmycorrhizal is therefore not supported. The use of mycorrhizal checklists for analysis of plant traits and evolution needs to be undertaken with care to ensure the validity of underlying data.

  13. RESPONSE OF TWO SUNFLOWER (HELIANTHUS ANNUUS L. GENOTYPES TO VA-MYCORRHIZAL INOCULATION AND PHOSPHORUS LEVELS

    Directory of Open Access Journals (Sweden)

    C.P. CHANDRASHEKARA, V.C. PATIL

    1995-01-01

    Full Text Available The performance of two sunflower genotypes (Morden and MSFH-8 with and without VA-mycorrhizal fungi at three P levels (38, 56 and 75 kg P2O5 ha-1 in vertisol of Dharwad was studied to determine the effect of mycorrhizal inoculation on plant growth, yield and P uptake. The results showed that the VAM inoculation increased sunflower yield (14%, total biomass (16%, oil content (3.1% and P uptake (30.5% over uninoculated control. The percent root colonization and chlamydo-spore count decreased with increasing P levels. The total biomass production, seed yield and P uptake of mycorrhizal plants at 38 kg P2O5 ha-1 more than the non-mycorrhizal plants at 75 kg P2O5 ha-1. The biomass and seed yield of mycorrhizal plants at same P level were more than the non-mycorrhizal plants. Mycorrhizal plants of Morden at 38 kg P2O5 ha-1 and MSFH-8 at 56 kg P2O5 ha-1 produced higher seed yield, oil content and total biomass than non-mycorrhizal plants supplied with 75 kg P2O5 ha-1. The results indicated that, VA-mycorrhizal inoculation helps in saving 25 and 50 percent of recommended dose of phosphatic fertilizer (75 kg P2O5 ha-1 in MSFH-8 (single cross hybrid and Morden (open pollinated variety, respectively.

  14. Underground resource allocation between individual networks of mycorrhizal fungi

    DEFF Research Database (Denmark)

    Mikkelsen, Bolette Lind; Rosendahl, Søren; Jakobsen, Iver

    2008-01-01

    * Fusions between individual mycelia of arbuscular mycorrhizal (AM) fungi have been observed in two-dimensional systems but never in soil systems. Here, phosphorus ((32)P) labelling was used to demonstrate nutrient transfer between individual mycelia and to investigate the possible role of anasto......* Fusions between individual mycelia of arbuscular mycorrhizal (AM) fungi have been observed in two-dimensional systems but never in soil systems. Here, phosphorus ((32)P) labelling was used to demonstrate nutrient transfer between individual mycelia and to investigate the possible role...... of G. mosseae overlapped. The transfer probably occurred via anastomoses between the mycelia as no transfer of (32)P was detected between the mycelia of different fungi at the second harvest. * The indicated ability of AM fungal mycelia to anastomose in soil has implications for the formation of large...

  15. Effects of organic farming on communities of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Lee, Si-Woo; Lee, Eun-Hwa; Eom, Ahn-Heum

    2008-03-01

    Red pepper (Capsicum annum L.) roots and soils representing different agricultural management practices such as conventional (CON), no-chemical (NOC), and organic farming systems (ORG) were collected from 32 farm field sites in Kyunggi, Korea to investigate the effects of these agricultural practices on arbuscular mycorrhizal (AM) symbiosis. ORG inoculum significantly increased plant growth compared to inoculum from CON and NOC. A community analysis of AM fungi (AMF) using morphological features of spores revealed that AMF spore abundance and species diversity were significantly higher in ORG than in CON. Additionally, a community analysis of AMF colonizing roots using a molecular technique revealed higher AMF diversity in ORG than in CON. These results suggest that agricultural practices significantly influence AM fungal community structure and mycorrhizal inoculum potential.

  16. Leaf elemental analysis in mycorrhizal post oak seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Boling, B.C. [Department of Biology, University of North Texas, P.O. Box 305220, Denton, TX 76203-5220 (United States); Naab, F.U. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States)]. E-mail: fun001@unt.edu; Smith, D. [Department of Biology, University of North Texas, P.O. Box 305220, Denton, TX 76203-5220 (United States); Duggan, J.L. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States); McDaniel, F.D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States)

    2006-09-15

    Growth and element assimilation was investigated in the leaves of post oak seedlings exposed to four different treatment combinations of fertilization and ectomycorrhizal inoculation. Element concentration was analyzed via particle-induced X-ray emission spectrometry (PIXE). PIXE detected 10 of the 13 essential macro and micronutrients: P, S, Mg, Ca, K, Cu, Zn, Mn, Fe and Cl. Mean growth and dry weight was significantly different across the treatment groups as well as the mean concentration of Mg, Al, S, K, Ca, Fe, Cu and Zn. The data suggest that fertilization rather than mycorrhizal inoculation had a stronger influence on nutrient uptake. This study is the first to analyze element concentration in post oak and to investigate the potential benefits of mycorrhizal symbiosis in post oak seedlings in terms of nutrient uptake.

  17. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    Science.gov (United States)

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Edible mycorrhizal mushrooms as sources of bioactive phenolic compounds.

    OpenAIRE

    João C. M. Barreira; Barros, Lillian; Martins, Anabela; Isabel C. F. R. Ferreira

    2011-01-01

    Mushrooms are emerging as one of the most appreciated foods on a global basis. Besides their nutritional properties and unique organoleptic characteristics, mushrooms might act as functional foods in view of the medicinal properties of their bioactive compounds [1,2]. Those medicinal properties are often due the antioxidant activity of specific molecules such as phenolic compounds [3]. In the present work, five edible mycorrhizal mushoom species (Amanita caesarea, Cortinarius anomalus, Co...

  19. Programming good relations - development of the arbuscular mycorrhizal symbiosis

    OpenAIRE

    Reinhardt, Didier

    2007-01-01

    The majority of plants live in symbiotic associations with fungi or bacteria that improve their nutrition. Critical steps in a symbiosis are mutual recognition and subsequently the establishment of an intimate association, which involves the penetration of plant tissues and, in many cases, the invasion of individual host cells by the microbial symbiont. Recent advances revealed that in the arbuscular mycorrhizal symbiosis with soil fungi of the order Glomeromycota, plant-derived signals attra...

  20. The role of mycorrhizal associations in plant potassium nutrition

    OpenAIRE

    Garcia, Kevin; Zimmermann, Sabine D.

    2014-01-01

    Potassium (K+) is one of the most abundant elements of soil composition but it's very low availability limits plant growth and productivity of ecosystems. Because this cation participates in many biological processes, its constitutive uptake from soil solution is crucial for the plant cell machinery. Thus, the understanding of strategies responsible of K+ nutrition is a major issue in plant science. Mycorrhizal associations occurring between roots and hyphae of underground fungi improve hydro...

  1. Arbuscular Mycorrhizal Symbiosis Alleviates Diesel Toxicity on Melilotus albus

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Ortega, H. A.; Alarcon, A.; Ferrera-Cerrato, R.; Zavaleta-Mancera, H. A.

    2009-07-01

    Petroleum hydrocarbons (PH) affect plant growth and development by limiting water absorption and nutrient availability. Arbuscular mycorrhizal fungi (AMF) have been demonstrated to increase plant tolerance of grass species to PH, but the performance of AMF on legume species during phytorremediation of PH-contaminated soils has been scarcely understood. Thus, this research evaluated the effects of AMF on tolerance and growth of Melilotus albus in a diesel-contaminated soil. (Author)

  2. Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile.

    Science.gov (United States)

    Mujica, María Isabel; Saez, Nicolás; Cisternas, Mauricio; Manzano, Marlene; Armesto, Juan J; Pérez, Fernanda

    2016-07-01

    Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses. © The Author 2016. Published by Oxford University Press on behalf of the Annals of

  3. Cell wall remodeling in mycorrhizal symbiosis: a way towards biotrophism

    Science.gov (United States)

    Balestrini, Raffaella; Bonfante, Paola

    2014-01-01

    Cell walls are deeply involved in the molecular talk between partners during plant and microbe interactions, and their role in mycorrhizae, i.e., the widespread symbiotic associations established between plant roots and soil fungi, has been investigated extensively. All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged. The exchange of molecules between the fungal and the plant cytoplasm takes place both through their plasma membranes and their cell walls; a functional compartment, known as the symbiotic interface, is thus defined. Among all the symbiotic interfaces, the complex intracellular interface of arbuscular mycorrhizal (AM) symbiosis has received a great deal of attention since its first description. Here, in fact, the host plasma membrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. By contrast, in ectomycorrhizae (ECM), where the fungus grows outside and between the root cells, plant and fungal cell walls are always in direct contact and form the interface between the two partners. The organization and composition of cell walls within the interface compartment is a topic that has attracted widespread attention, both in ecto- and endomycorrhizae. The aim of this review is to provide a general overview of the current knowledge on this topic by integrating morphological observations, which have illustrated cell wall features during mycorrhizal interactions, with the current data produced by genomic and transcriptomic approaches. PMID:24926297

  4. The role of mycorrhizal associations in plant potassium nutrition

    Directory of Open Access Journals (Sweden)

    Kevin eGarcia

    2014-07-01

    Full Text Available Potassium (K+ is one of the most abundant elements of soil composition but its very low availability limits plant growth and productivity of ecosystems. Because this cation participates in many biological processes, its constitutive uptake from soil solution is crucial for the plant cell machinery. Thus, the understanding of strategies responsible of K+ nutrition is a major issue in plant science. Mycorrhizal associations occurring between roots and hyphae of underground fungi improve hydro-mineral nutrition of the majority of terrestrial plants. The contribution of this mutualistic symbiosis to the enhancement of plant K+ nutrition is not well understood and poorly studied so far. This mini-review examines the current knowledge about the impact of both arbuscular mycorrhizal and ectomycorrhizal symbioses on the transfer of K+ from the soil to the plants. A model summarizing plant and fungal transport systems identified and hypothetically involved in K+ transport is proposed. In addition, some data related to benefits for plants provided by the improvement of K+ nutrition thanks to mycorrhizal symbioses are presented.

  5. The role of mycorrhizal associations in plant potassium nutrition

    Science.gov (United States)

    Garcia, Kevin; Zimmermann, Sabine D.

    2014-01-01

    Potassium (K+) is one of the most abundant elements of soil composition but it's very low availability limits plant growth and productivity of ecosystems. Because this cation participates in many biological processes, its constitutive uptake from soil solution is crucial for the plant cell machinery. Thus, the understanding of strategies responsible of K+ nutrition is a major issue in plant science. Mycorrhizal associations occurring between roots and hyphae of underground fungi improve hydro-mineral nutrition of the majority of terrestrial plants. The contribution of this mutualistic symbiosis to the enhancement of plant K+ nutrition is not well understood and poorly studied so far. This mini-review examines the current knowledge about the impact of both arbuscular mycorrhizal and ectomycorrhizal symbioses on the transfer of K+ from the soil to the plants. A model summarizing plant and fungal transport systems identified and hypothetically involved in K+ transport is proposed. In addition, some data related to benefits for plants provided by the improvement of K+ nutrition thanks to mycorrhizal symbioses are presented. PMID:25101097

  6. Growth response of Pterocarpus soyauxii and Lophira alata seedlings to host soil mycorrhizal inocula in relation to land use types.

    NARCIS (Netherlands)

    Onguene, N.A.; Ngonkeu, L.E.M.; Kuyper, T.W.

    2011-01-01

    Deficiency in mycorrhizal inoculum in soils due to land use types (LUT) can be alleviated by quantity and quality inoculum addition. A bioassay was carried out to determine how host soil mycorrhizal inoculum influenced mycorrhizal colonization, carbon allocation and partitioning of seedlings of two

  7. Microscopic characterization of orchid mycorrhizal fungi: Scleroderma as a putative novel orchid mycorrhizal fungus of Vanilla in different crop systems.

    Science.gov (United States)

    González-Chávez, Ma Del Carmen A; Torres-Cruz, Terry J; Sánchez, Samantha Albarrán; Carrillo-González, Rogelio; Carrillo-López, Luis Manuel; Porras-Alfaro, Andrea

    2018-02-01

    Vanilla is an orchid of economic importance widely cultivated in tropical regions and native to Mexico. We sampled three species of Vanilla (V. planifolia, V. pompona, and V. insignis) in different crop systems. We studied the effect of crop system on the abundance, type of fungi, and quality of pelotons found in the roots using light and electron microscopy and direct sequencing of mycorrhizal structures. Fungi were identified directly from pelotons obtained from terrestrial roots of vanilla plants in the flowering stage. Root samples were collected from plants in crop systems located in the Totonacapan area in Mexico (states of Puebla and Veracruz). DNA was extracted directly from 40 pelotons and amplified using ITS rRNA sequencing. Peloton-like structures were observed, presenting a combination of active pelotons characterized by abundant hyphal coils and pelotons in various stages of degradation. The most active pelotons were observed in crop systems throughout living tutors (host tree) in comparison with roots collected from dead or artificial tutors. Fungi identified directly from pelotons included Scleroderma areolatum, a common ectomycorrhizal fungus that has not been reported as a mycorrhizal symbiont in orchids. Direct amplification of pelotons also yielded common plant pathogens, including Fusarium and Pyrenophora seminiperda, especially in those sites with low colonization rates, and where large numbers of degraded pelotons were observed. This research reports for the first time the potential colonization of Vanilla by Scleroderma, as a putative orchid mycorrhizal symbiont in four sites in Mexico and the influence of crop system on mycorrhizal colonization on this orchid.

  8. Mycorrhizal Productivity Following Woody Plant Invasion of Grassland

    Science.gov (United States)

    Boutton, T. W.; Rowe, H. I.; Ariza, M. C.; Miller, R. M.; Filley, T. R.

    2008-12-01

    Mycorrhizal fungi play an important role in soil carbon storage and dynamics through the production of recalcitrant organic compounds (e.g., glomalin and chitin), and through the production of hyphae which entangle and enmesh soil particles to form aggregates which physically protect organic matter from decomposer organisms. Despite these important functions, little is known regarding rates of mycorrhizal productivity and how these rates might be influenced by changes in plant community composition. We quantified mycorrhizal production in a subtropical savanna parkland in southern Texas where woody plants have invaded areas that were once open grassland. Mycorrhizal ingrowth bags (3 x 10 cm) were made from 50 μm nylon mesh, filled with sterile sand (200-600 μm particle size), and deployed in the field in triplicate in remnant grasslands (n=15), and in woody plant stands (n=13) ranging in age from 15 to 86 yrs. Ingrowth bags were installed in May and harvested in Oct 2007 after 156 days. Hyphae were isolated by flotation/filtration, cleaned thoroughly to remove sand, freeze-dried, and weighed. Microscopic examination indicated that nearly all hyphae recovered from ingrowth bags were from arbuscular mycorrhizal fungi. During the ingrowth period, nearly 4X more hyphal biomass accumulated in wooded areas (9.00 ± 3.84 g m- 2) compared to remnant grasslands (2.35 ± 0.56 g m-2). Hyphal productivity rates increased linearly with woody plant stand age (r = 0.89) from 15 ± 4 mg m-2 day-1 in grasslands (time 0) up to 58-98 mg m-2 day-1 in wooded areas >65 yrs old. When these productivity rates are annualized, we find that hyphal productivity represents approximately 4% of aboveground net primary productivity (ANPP) in wooded areas, and 2% of ANPP in remnant grasslands. These observations are consistent with concurrent studies showing that glomalin concentrations and chitinase enzyme activity both increase in soils with time following woody encroachment into grassland

  9. Towards the antioxidant and chemical characterization of mycorrhizal mushrooms from Northeast Portugal

    OpenAIRE

    Filipa S. Reis; Sandrina A. Heleno; Barros, Lillian; Sousa, Maria João; Martins, Anabela; Santos-Buelga, Celestino; Isabel C. F. R. Ferreira

    2011-01-01

    Mushrooms are widely appreciated all over the world for their nutritional properties and pharmacological value as sources of important bioactive compounds. Mycorrhizal macrofungi associate with plant roots constituting a symbiotic relationship. This symbiosis could influence the production of secondary metabolites, including bioactive compounds. We focused on the evaluation of antioxidant potential and chemical composition of mycorrhizal mushrooms species from Northeast Portugal: Amanita cae...

  10. Mycelium of arbuscular mycorrhizal fungi (AMF) from different genera: form function and detection

    NARCIS (Netherlands)

    Dodd, J.C.; Boddington, C.L.; Rodriguez, A.; Gonzalez-Chavez, C.; Marsur, I.

    2000-01-01

    It is often assumed that all species of arbuscular mycorrhizal fungi (AMF) have the same function because of the ubiquity of the arbuscular mycorrhizal symbiosis and the fact that all AMF occupy the same plant/soil niche. Despite apparent differences in the timing of evolutionary divergence and the

  11. Role of mycorrhizal fungi and salicylic acid in salinity tolerance of ...

    African Journals Online (AJOL)

    Salinity is one of the common agricultural and biological problems. Most researchers showed that inoculation of plants with mycorrhizal fungi and using salicylic acid increase tolerance of plants due to salinity. In this study, the effect of mycorrhizal fungi, including Glomus mosseae, Glomus intraradices, and salicylic acid (0.2 ...

  12. Phosphate uptake from phytate due to hyphae-mediated phytase activity by arbuscular mycorrhizal maize

    NARCIS (Netherlands)

    Wang, Xinxin; Hoffland, Ellis; Feng, Gu; Kuijper, Thomas

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We

  13. Symbiont identity matters: carbon and phosphorus fluxes between Medicago truncatula and different arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Lendenmann, Mark; Thonar, Cécile; Barnard, Romain L; Salmon, Yann; Werner, Roland A; Frossard, Emmanuel; Jansa, Jan

    2011-11-01

    Many studies have scrutinized the nutritional benefits of arbuscular mycorrhizal associations to their host plants, while the carbon (C) balance of the symbiosis has often been neglected. Here, we present quantification of both the C costs and the phosphorus (P) uptake benefits of mycorrhizal association between barrel medic (Medicago truncatula) and three arbuscular mycorrhizal fungal species, namely Glomus intraradices, Glomus claroideum, and Gigaspora margarita. Plant growth, P uptake and C allocation were assessed 7 weeks after sowing by comparing inoculated plants with their non-mycorrhizal counterparts, supplemented with different amounts of P. Isotope tracing ³³P and ¹³C) was used to quantify both the mycorrhizal benefits and the costs, respectively. G. intraradices supported greatest plant P acquisition and incurred high C costs, which lead to similar plant growth benefits as inoculation with G. claroideum, which was less efficient in supporting plant P acquisition, but also required less C. G. margarita imposed large C requirement on the host plant and provided negligible P uptake benefits. However, it did not significantly reduce plant growth due to sink strength stimulation of plant photosynthesis. A simple experimental system such as the one established here should allow quantification of mycorrhizal costs and benefits routinely on a large number of experimental units. This is necessary for rapid progress in assessment of C fluxes between the plants and different mycorrhizal fungi or fungal communities, and for understanding the dynamics between mutualism and parasitism in mycorrhizal symbioses.

  14. Resilience of arctic mycorrhizal fungal communities after wildfire facilitated by resprouting shrubs

    Science.gov (United States)

    Rebecca E. Hewitt; Elizabeth Bent; Teresa N. Hollingsworth; F. Stuart Chapin; D. Lee. Taylor

    2013-01-01

    Climate-induced changes in the tundra fire regime are expected to alter shrub abundance and distribution across the Arctic. However, little is known about how fire may indirectly impact shrub performance by altering mycorrhizal symbionts. We used molecular tools, including ARISA and ITS sequencing, to characterize the mycorrhizal communities on resprouting ...

  15. Arbuscular mycorrhizal fungi status of some crops in the cross river ...

    African Journals Online (AJOL)

    The incidence of arbuscular mycorrhizal fungi (AMF) colonization and rhizospheric spore prevalence of ten crops was studied in relation to their foliar concentration of nitrogen, phosphorus and potassium in the Calabar area of the Cross River Basin of Nigeria in order to determine their mycorrhizal status. All crops studied ...

  16. Decline of carpophores of mycorrhizal fungi in stands of Pinus sylvestris

    NARCIS (Netherlands)

    Termorshuizen, A.J.

    1990-01-01

    The carpophores of mycorrhizal fungi have declined drastically during this century in the Netherlands and in other European countries. In contrast, saprophytic and pathogenic fungi did not show a significant change. In this thesis, the possible causes of the decline of mycorrhizal mycoflora

  17. Plant and mycorrhizal weathering at the laboratory mesocosm scale

    Science.gov (United States)

    Andrews, M. Y.; Leake, J.; Banwart, S. A.; Beerling, D. J.

    2011-12-01

    The evolutionary development of large vascular land plants in the Paleozoic is hypothesized to have enhanced weathering of Ca and Mg silicate minerals. This plant-centric view overlooks the fact that plants and their associated mycorrhizal fungi co-evolved. Many weathering processes usually ascribed to plants may actually be driven by the combined activities of roots and mycorrhizal fungi. This study focuses on two key evolutionary events in plant and fungal evolution: 1) the transition from gymnosperm-only to mixed angiosperm-gymnosperm forests in the Mesozoic and 2) the similarly timed rise of ectomycorrhizal fungi (EM) in a previously arbuscular mycorrhizal (AM) only world. Here we present results from a novel mesocosm-scale laboratory experiment designed to allow investigation of plant- and mycorrhizae-driven carbon fluxes and mineral weathering at different soil depths, and under ambient (400 ppm) and elevated (1500 ppm) atmospheric CO2. To test our hypothesis that photosynthetic carbon flux from the plant to the roots and fungal partner drives biological weathering of minerals, we studied five mycorrhizal plant species: the gymnosperms Sequoia sempervirens (AM), Pinus sylvestris (EM) and Ginkgo biloba (AM), and two angiosperms, Magnolia grandiflora (AM) and Betula pendula (EM). This long term (7-9 months) experiment was grown in controlled environment chambers, with replicated systems at two atmospheric CO2 levels. Each mycorrhizal plant had access to isolated horizontal mesh cores containing crushed granite and basalt at three depths, in a compost:sand (50:50 vol:vol) bulk substrate, with appropriate plant-free and mineral-free controls. 14CO2 pulse-labeling provided a snapshot of the magnitude, timing, and allocation of carbon through the atmosphere-plant-fungi-soil system and also measured mycorrhizal fungal activity associated with the target granite and basalt. Total plant and fungal biomass were also assessed in relation to +/- mineral treatments and

  18. Responses of mycorrhizal fungi and other rootassociated fungi to climate change

    DEFF Research Database (Denmark)

    Merrild, Marie Porret

    Climate change is expected to affect many terrestrial ecosystem processes. Mycorrhizal fungi are important to soil carbon (C) and nutrient cycling thus changes in abundance of mycorrhizal fungi could alter ecosystem functioning. The aim of the present thesis was therefore to investigate responses...... of mycorrhizal fungi to climate change in a seasonal and long-term perspective. Effects of elevated CO2 (510 ppm), night-time warming and extended summer drought were investigated in the long-term field experiment CLIMAITE located in a Danish semi-natural heathland. Mycorrhizal colonization was investigated...... levels. Colonization by arbuscular mycorrhizal (AM) fungi increased under elevated CO2 and warming in spring while ericoid mycorrhiza (ErM) colonisation decreased in response to drought and warming. Increased AM colonization correlated with higher phosphorus and nitrogen root pools. Dark septate...

  19. Effect of mycorrhizal inoculations on the growth of Shorea robusta seedlings

    Directory of Open Access Journals (Sweden)

    ASHWANI TAPWAL

    2015-05-01

    Full Text Available Tapwal A, Kumar R, Borah D. 2015. Effect of mycorrhizal inoculations on the growth of Shorea robusta seedlings. Nusantara Bioscience 7: 1-5. Shorea robusta is one of important timber yielding tree species of northeast India and known to have both ectomycorrhizal (EcM and endomycorrhizal (AM associations. It is hypothesized that under favorable conditions different mycorrhizal fungi present in soil develop symbiotic association with fine roots of trees. In present investigations, mycorrhizal inoculum of EcM and AM fungi applied to S. robusta seedlings raised in polyethylene bags in nursery. Observations on growth characters and mycorrhizal colonization were recorded at the interval of three months. The results revealed that irrespective of type of mycorrhizal inoculation, growth of the seedlings increased significantly in comparison to control. Maximum growth was observed for the seedlings inoculated with EcM alone, followed by dual inoculations (EcM+AM, seedlings inoculated with AM fungi and minimum in control.

  20. Role and influence of mycorrhizal fungi on radiocesium accumulation by plants

    Energy Technology Data Exchange (ETDEWEB)

    Dupre de Boulois, H. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Joner, E.J. [Bioforsk Soil and Environment, FredrikA Dahls vei 20, N-1432 As (Norway); Leyval, C. [LIMOS, Nancy University, CNRS, Faculte des Sciences, BP239, 54506 Vandoeuvre-les-Nancy, Cedex (France); Jakobsen, I. [Biosystems Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Chen, B.D. [Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Roos, P. [Radiation Research Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Thiry, Y.; Rufyikiri, G. [Biosphere Impact Assessment, SCK.CEN, Foundation of Public Utility, 200 Boeretang, 2400 Mol (Belgium); Delvaux, B. [Universite catholique de Louvain, Unite des Sciences du Sol, Croix du Sud 2/10, 1348 Louvain-la-Neuve (Belgium); Declerck, S. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)], E-mail: declerck@mbla.ucl.ac.be

    2008-05-15

    This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies.

  1. Effects of arbuscular mycorrhizal fungi on nutrient uptake of maize in reclaimed soil

    Energy Technology Data Exchange (ETDEWEB)

    Bi, Y.; Hu, Z.; Si, J.; Quan, W. [China University of Mining and Technology (CUMT), Beijing (China). Dept. of Resources Exploitation Engineering

    2002-05-01

    An experiment was carried out on the effects of arbuscular mycorrhizal (AM) fungi, glomus mosseae, on the growth and nutrient uptaking of maize in reclaimed soil with coal fly ash layers at different depths. The research shows that plant yields increase with soil depth. Mycorrhizal plants can absorb more nutrients than non-mycorrhizal ones, and transport less Na to shoot, protecting plants from the excessive accumulation of Na. Plant biomass and nutrient content for mycorrhizal plants in reclaimed soil with a small soil thickness of 5 cm and a great fly ash thickness of 10 cm are higher than those for non-mycorrhizal plants in reclaimed soil with a great soil thickness of 10 cm and a small fly ash thickness of 5 cm. Arbuscular mycorrhizae have a potential to counteract the effect induced by a small thickness of covered soil, and so can reduce reclamation fee. 20 refs., 6 tabs.

  2. Mycorrhizal fungal diversity and community composition in a lithophytic and epiphytic orchid.

    Science.gov (United States)

    Xing, Xiaoke; Gai, Xuege; Liu, Qiang; Hart, Miranda M; Guo, Shunxing

    2015-05-01

    Some orchid species are present as epiphytes and lithophytes in the same habitat, but little is known about the differences of their mycorrhizal fungal communities. We used Coelogyne viscosa, which occurs both as an epiphyte and a lithophyte, as a study system to investigate orchid mycorrhizal fungal communities in lithophytes and epiphytes in Xishuangbanna National Nature Reserve (Yunnan Province, China). Twenty-three fungal operational taxonomic units (OTUs) from 18 sampling sites were identified. Results indicated that mycorrhizal fungal community composition was different between epi- and lithophytes. When we analyzed the Tulasnellaceae and Sebacinales communities separately, we found that the Sebacinales fungal communities were significantly different in the two growth habitats, but the Tulasnellaceae fungal communities were not. Our results provide evidence for distinct orchid mycorrhiza fungal communities depending on the growth habitat of the orchid. Consistent with some recent investigations of mycorrhizal fungus community composition, this study suggests that for one orchid, growth habitat affects mycorrhizal symbioses.

  3. [Effects of mycorrhizal colonization and medicine quality of Paris polyphylla var. yunnanensis inoculated by different foreign AM fungi species].

    Science.gov (United States)

    Zhou Nong; Ding, Bo; Feng, Yuan; Qi, Wen-hua; Zhang, Hua; Guo, Dong-qin; Xiang, Jun

    2015-08-01

    After 28 foreign species of AM fungi were inoculated in sterilized soil, the effects of the AM mycorrhizal colonization and the medicine quality of Paris polyphylla var. yunnanensis were observed by combination of inoculation test in pot at room temperature and instrumental analysis. The results showed that, compared with control group (CK), the inoculation of foreign AM fungi in the soil influenced the spore density, mycorrhizal infection rate, and colonization intensity of AM fungi in root system of P. polyphylla var. yunnanensis. The inoculation of foreign AM fungi enhanced the mycorrhiza viability of P. polyphylla var. yunnanensis by increasing the activity of succinic dehydrogenase (SDH) and alkaline phosphatase (ALP) in intraradical hyphae. The content of single steroid saponin in rhizome of P. polyphylla var. yunnanensis showed variation after P. polyphylla var. yunnanensis was inoculated by different foreign species of AM fungi, which was beneficial for increasing the medicine quality; however, the kinds of steroid saponin showed no difference. In a degree, there was a selectivity of symbiosis between P. polyphylla var. yunnanensis and foreign AM fungi. And we found that the Claroideoglomus claroideum and Racocetra coralloidea were best foreign AM fungi species for cultivating P. polyphylla var. yunnanensis under field condition.

  4. Root endophyte symbiosis in vitro between the ectomycorrhizal basidiomycete Tricholoma matsutake and the arbuscular mycorrhizal plant Prunus speciosa.

    Science.gov (United States)

    Murata, Hitoshi; Yamada, Akiyoshi; Yokota, Satoru; Maruyama, Tsuyoshi; Endo, Naoki; Yamamoto, Kohei; Ohira, Tatsuro; Neda, Hitoshi

    2014-05-01

    We previously reported that Tricholoma matsutake and Tricholoma fulvocastaneum, ectomycorrhizal basidiomycetes that associate with Pinaceae and Fagaceae, respectively, in the Northern Hemisphere, could interact in vitro as a root endophyte of somatic plants of Cedrela odorata (Meliaceae), which naturally harbors arbuscular mycorrhizal fungi in South America, to form a characteristic rhizospheric colony or "shiro". We questioned whether this phenomenon could have occurred because of plant-microbe interactions between geographically separated species that never encounter one another in nature. In the present study, we document that these fungi formed root endophyte interactions and shiro within 140 days of inoculation with somatic plants of Prunus speciosa (=Cerasus speciosa, Rosaceae), a wild cherry tree that naturally harbors arbuscular mycorrhizal fungi in Japan. Compared with C. odorata, infected P. speciosa plants had less mycelial sheath surrounding the exodermis, and the older the roots, especially main roots, the more hyphae penetrated. In addition, a large number of juvenile roots were not associated with hyphae. We concluded that such root endophyte interactions were not events isolated to the interactions between exotic plants and microbes but could occur generally in vitro. Our pure culture system with a somatic plant allowed these fungi to express symbiosis-related phenotypes that varied with the plant host; these traits are innately programmed but suppressed in nature and could be useful in genetic analyses of plant-fungal symbiosis.

  5. Occurrence of similar mycoviruses in pathogenic, saprotrophic and mycorrhizal fungi inhabiting the same forest stand.

    Science.gov (United States)

    Vainio, Eeva J; Pennanen, Taina; Rajala, Tiina; Hantula, Jarkko

    2017-03-01

    Fungal viruses (mycoviruses) are considered to be highly host specific, but phylogenetic analysis supports the occasional occurrence of horizontal transmission between species. We used an extensive sampling strategy to investigate whether similar viruses occur in more than one fungal species of the same forest habitat. Mycelial samples were collected from in-growth mesh bags (N = 259), fruiting bodies (N = 173) and cultured isolates (N = 68) at a forest site where the spatial distribution of viral infections in clonal individuals of the wood decay fungus Heterobasidion parviporum was mapped in detail earlier. The investigation revealed previously known Heterobasidion viruses in ∼2% of the single or pooled mycorrhizal samples from mesh bags, ∼3% of the fruiting body samples and none of the fungal cultures analyzed. Novel virus strains distinct from known Heterobasidion viruses were detected in cultures of ectomycorrhizal fungi (Lactarius tabidus, L. rufus) and saprotrophic fungi (Megacollybia platyphylla, Mucoraceae spp.). Overall, our results support the view that mycoviruses do not readily cross species borders. Regarding potential virocontrol applications, the introduction of Heterobasidion viruses into natural habitats is not expected to cause a major infection pressure towards the indigenous fungal community. However, the ecological consequences of the putative interspecies virus transmission events detected require further investigation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Optimization of the production of mycorrhizal inoculum on substrate with organic fertilizer

    Directory of Open Access Journals (Sweden)

    Ieda R Coelho

    2014-12-01

    Full Text Available The system for production of inoculum of arbuscular mycorrhizal fungi (AMF using sand and vermiculite irrigated with nutrient solution is promising. However, organic amendments added to the substrate can stimulate sporulation of AMF and replace the nutrient solution. The aim of this study was to maximize the production of AMF (Acaulospora longula, Claroideoglomus etunicatum, Dentiscutata heterogama and Gigaspora albida using selected organic substrates (vermicompost, coir dust and Tropstrato together with sand and vermiculite. The production of spores varied among the tested AMF and according to the organic source added to the substrate. The vermicompost promoted higher sporulation of A. longula in relation to the other AMF and substrates. The Tropstrato® inhibited the sporulation of D. heterogama while the reproduction of C. etunicatum was not affected by the organic compounds. The inoculum of A. longula also showed a high number of infective propagules and promoted biomass accumulation in maize plants. The system of inoculum production using sand and vermiculite + 10% vermicompost favors the production of infective inoculum of A. longula with the fungus benefiting growth of corn plants.

  7. RAM1 and RAM2 function and expression during arbuscular mycorrhizal symbiosis and Aphanomyces euteiches colonization.

    Science.gov (United States)

    Gobbato, Enrico; Wang, Ertao; Higgins, Gillian; Bano, Syeda Asma; Henry, Christine; Schultze, Michael; Oldroyd, Giles E D

    2013-10-01

    The establishment of the symbiotic interaction between plants and arbuscular mycorrhizal (AM) fungi requires a very tight molecular dialogue. Most of the known plant genes necessary for this process are also required for nodulation in legume plants and only very recently genes specifically required for AM symbiosis have been described. Among them we identified RAM (Reduced Arbuscular Mycorrhization)1 and RAM2, a GRAS transcription factor and a GPAT respectively, which are critical for the induction of hyphopodia formation in AM fungi. RAM2 function is also required for appressoria formation by the pathogen Phytophtora palmivora. Here we investigated the activity of RAM1 and RAM2 promoters during mycorrhization and the role of RAM1 and RAM2 during infection by the root pathogen Aphanomyces euteiches. pRAM1 is activated without cell type specificity before hyphopodia formation, while pRAM2 is specifically active in arbusculated cells providing evidence for a potential function of cutin momomers in the regulation of arbuscule formation. Furthermore, consistent with what we observed with Phytophtora, RAM2 but not RAM 1 is required during Aphanomyces euteiches infection.

  8. Optimization of the production of mycorrhizal inoculum on substrate with organic fertilizer

    Science.gov (United States)

    Coelho, Ieda R; Pedone-Bonfim, Maria VL; Silva, Fábio SB; Maia, Leonor C

    2014-01-01

    The system for production of inoculum of arbuscular mycorrhizal fungi (AMF) using sand and vermiculite irrigated with nutrient solution is promising. However, organic amendments added to the substrate can stimulate sporulation of AMF and replace the nutrient solution. The aim of this study was to maximize the production of AMF (Acaulospora longula, Claroideoglomus etunicatum, Dentiscutata heterogama and Gigaspora albida) using selected organic substrates (vermicompost, coir dust and Tropstrato) together with sand and vermiculite. The production of spores varied among the tested AMF and according to the organic source added to the substrate. The vermicompost promoted higher sporulation of A. longula in relation to the other AMF and substrates. The Tropstrato® inhibited the sporulation of D. heterogama while the reproduction of C. etunicatum was not affected by the organic compounds. The inoculum of A. longula also showed a high number of infective propagules and promoted biomass accumulation in maize plants. The system of inoculum production using sand and vermiculite + 10% vermicompost favors the production of infective inoculum of A. longula with the fungus benefiting growth of corn plants. PMID:25763020

  9. Comparison of green and albino individuals of the partially mycoheterotrophic orchid Epipactis helleborine on molecular identities of mycorrhizal fungi, nutritional modes and gene expression in mycorrhizal roots.

    Science.gov (United States)

    Suetsugu, Kenji; Yamato, Masahide; Miura, Chihiro; Yamaguchi, Katsushi; Takahashi, Kazuya; Ida, Yoshiko; Shigenobu, Shuji; Kaminaka, Hironori

    2017-03-01

    Some green orchids obtain carbon from their mycorrhizal fungi, as well as from photosynthesis. These partially mycoheterotrophic orchids sometimes produce fully achlorophyllous, leaf-bearing (albino) variants. Comparing green and albino individuals of these orchids will help to uncover the molecular mechanisms associated with mycoheterotrophy. We compared green and albino Epipactis helleborine by molecular barcoding of mycorrhizal fungi, nutrient sources based on 15 N and 13 C abundances and gene expression in their mycorrhizae by RNA-seq and cDNA de novo assembly. Molecular identification of mycorrhizal fungi showed that green and albino E. helleborine harboured similar mycobionts, mainly Wilcoxina. Stable isotope analyses indicated that albino E. helleborine plants were fully mycoheterotrophic, whereas green individuals were partially mycoheterotrophic. Gene expression analyses showed that genes involved in antioxidant metabolism were upregulated in the albino variants, which indicates that these plants experience greater oxidative stress than the green variants, possibly due to a more frequent lysis of intracellular pelotons. It was also found that some genes involved in the transport of some metabolites, including carbon sources from plant to fungus, are higher in albino than in green variants. This result may indicate a bidirectional carbon flow even in the mycoheterotrophic symbiosis. The genes related to mycorrhizal symbiosis in autotrophic orchids and arbuscular mycorrhizal plants were also upregulated in the albino variants, indicating the existence of common molecular mechanisms among the different mycorrhizal types. © 2017 John Wiley & Sons Ltd.

  10. The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Aerts, A.; Ahren, D.; Brun, A.; Danchin, E. G. J.; Duchaussoy, F.; Gibon, J.; Kohler, A.; Lindquist, E.; Peresa, V.; Salamov, A.; Shapiro, H. J.; Wuyts, J.; Blaudez, D.; Buee, M.; Brokstein, P.; Canback, B.; Cohen, D.; Courty, P. E.; Coutinho, P. M.; Delaruelle, C.; Detter, J. C.; Deveau, A.; DiFazio, S.; Duplessis, S.; Fraissinet-Tachet, L.; Lucic, E.; Frey-Klett, P.; Fourrey, C.; Feussner, I.; Gay, G.; Grimwood, J.; Hoegger, P. J.; Jain, P.; Kilaru, S.; Labbe, J.; Lin, Y. C.; Legue, V.; Le Tacon, F.; Marmeisse, R.; Melayah, D.; Montanini, B.; Muratet, M.; Nehls, U.; Niculita-Hirzel, H.; Secq, M. P. Oudot-Le; Peter, M.; Quesneville, H.; Rajashekar, B.; Reich, M.; Rouhier, N.; Schmutz, J.; Yin, T.; Chalot, M.; Henrissat, B.; Kues, U.; Lucas, S.; Van de Peer, Y.; Podila, G. K.; Polle, A.; Pukkila, P. J.; Richardson, P. M.; Rouze, P.; Sanders, I. R.; Stajich, J. E.; Tunlid, A.; Tuskan, G.; Grigoriev, I. V.

    2007-08-10

    Mycorrhizal symbioses the union of roots and soil fungi are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants 1, 2. Boreal, temperate and montane forests all depend on ectomycorrhizae1. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are

  11. Mycorrhizal fungi show regular community compositions in natural ecosystems.

    Science.gov (United States)

    Verbruggen, Erik; Sheldrake, Merlin; Bainard, Luke D; Chen, Baodong; Ceulemans, Tobias; De Gruyter, Johan; Van Geel, Maarten

    2017-10-06

    Dissimilarity overlap curve analysis has shown that 'universality' is a common feature in many complex microbial communities, suggesting that the same taxa interact in a similar manner when shared between communities. We present evidence that arbuscular mycorrhizal fungi, common plant root symbionts, show universal community compositions in natural ecosystems and that this pattern is conserved even at larger spatial scales. However, universality was not detected in agricultural ecosystems potentially implying that agricultural symbiont communities are formed in a different manner.The ISME Journal advance online publication, 6 October 2017; doi:10.1038/ismej.2017.169.

  12. [Effects of arbuscular mycorrhizal fungi on terpenoids in Isodon adenantha].

    Science.gov (United States)

    Han, Bing-Yang; Wang, Ke-Dong; Zhou, Nong; Jiang, Bei

    2013-02-01

    To observe the effects of Arbuscular Mycorrhizal (AM) fungi on terpenoids in Isodon adenantha. Three different treated plant groups were divided as followings: indoor inoculation with AM fungi, non-inoculation with AM fungi, and outdoor natural growth, the effects of AM fungi on the major terpenoids in Isodon adenantha were evaluated. AM fungi had little influence on the content of terpenoids in underground part of Isodon adenantha, but they showed great impact on the content of terpenoids in the aerial part of the plant. The content of terpenoids in the aerial part of Isodon adenantha is positively correlated with AM fungi.

  13. Nitrogen isotope fractionation during N uptake via arbuscular mycorrhizal and ectomycorrhizal fungi into grey alder.

    Science.gov (United States)

    Schweiger, Peter F

    2016-10-20

    Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi affect plant nitrogen (N) dynamics. Plant N isotope patterns have been used to characterise the contribution of ECM fungi to plant N uptake. By quantifying and comparing the effects of an AM and an ECM fungus on growth, N uptake and isotopic composition of one host plant grown at different relative N supply levels, the aim of this study was to improve the mechanistic understanding of natural 15N abundance patterns in mycorrhizal plants and their underlying causes. Grey alders were inoculated with one ECM fungus or one AM fungus or left non-mycorrhizal. Plants were grown under semi-hydroponic conditions and were supplied with three rates of relative N supply ranging from deficient to luxurious. Neither mycorrhizal fungus increased plant growth or N uptake. AM root colonisation had no effect on whole plant δ15N and decreased foliar δ 15N only under N deficiency. The roots of these plants were 15N-enriched. ECM root colonisation consistently decreased foliar and whole plant δ15N. It is concluded, that both mycorrhizal fungi contributed to plant N uptake into the shoot. Nitrogen isotope fractionation during N assimilation and transformations in fungal mycelia is suggested to have resulted in plants receiving 15N-depleted N via the mycorrhizal uptake pathways. Negative mycorrhizal growth effects are explained by symbiotic resource trade on carbon and N and decreased direct plant N uptake. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. Resource allocation in an annual herb: Effects of light, mycorrhizal fungi, and defoliation

    Science.gov (United States)

    Aguilar-Chama, Ana; Guevara, Roger

    2016-02-01

    Concurrent interactions and the availability of resources (e.g., light) affect the cost/benefit balance during mutualistic and antagonistic interactions, as well as plant resource allocation patterns. Mycorrhizal interactions and herbivory concur in most plants, where mycorrhizae can enhance the uptake of soil nutrients by plants as well as consuming a large fraction of the plant's carbon, and defoliation usually reduces light interception and photosynthesis, thereby causing direct losses to the hosts of mycorrhizal fungi. Both types of interactions affect the carbon budget of their host plants and thus we predict that the relative costs of herbivory and mycorrhizal colonization will increase when photosynthesis is reduced, for instance in light limited environments. We conducted a greenhouse experiment using Datura stramonium to investigate the effects of defoliation and mycorrhizal inoculation on the resource allocation patterns in two different light environments. Defoliated plants overcompensated in terms of leaf mass in both light environments, but total seed mass per fruit was negatively affected by defoliation in both light environments. Mycorrhizal inoculation had a positive effect on vegetative growth and the leaf nitrogen content, but defoliation negates the benefit of mycorrhizal interactions in terms of the leaf nitrogen content. In general, D. stramonium compensated for the relative costs of concurrent mycorrhizal interactions and defoliation; plants that lacked both interactions exhibited the same performance as plants with both types of interactions.

  15. Enrichment of arbuscular mycorrhizal fungi in a contaminated soil after rehabilitation

    Directory of Open Access Journals (Sweden)

    Patrícia Lopes Leal

    Full Text Available Abstract Spore counts, species composition and richness of arbuscular mycorrhizal fungi, and soil glomalin contents were evaluated in a soil contaminated with Zn, Cu, Cd and Pb after rehabilitation by partial replacement of the contaminated soil with non-contaminated soil, and by Eucalyptus camaldulensis planting with and without Brachiaria decumbens sowing. These rehabilitation procedures were compared with soils from contaminated non-rehabilitated area and non-contaminated adjacent soils. Arbuscular mycorrhizal fungi communities attributes were assessed by direct field sampling, trap culture technique, and by glomalin contents estimate. Arbuscular mycorrhizal fungi was markedly favored by rehabilitation, and a total of 15 arbuscular mycorrhizal fungi morphotypes were detected in the studied area. Species from the Glomus and Acaulospora genera were the most common mycorrhizal fungi. Number of spores was increased by as much as 300-fold, and species richness almost doubled in areas rehabilitated by planting Eucalyptus in rows and sowing B. decumbens in inter-rows. Contents of heavy metals in the soil were negatively correlated with both species richness and glomalin contents. Introduction of B. decumbens together with Eucalyptus causes enrichment of arbuscular mycorrhizal fungi species and a more balanced community of arbuscular mycorrhizal fungi spores in contaminated soil.

  16. Plant interspecific differences in arbuscular mycorrhizal colonization as a result of soil carbon addition.

    Science.gov (United States)

    Eschen, René; Müller-Schärer, Heinz; Schaffner, Urs

    2013-01-01

    Soil nutrient availability and colonization by arbuscular mycorrhizal fungi are important and potentially interacting factors shaping vegetation composition and succession. We investigated the effect of carbon (C) addition, aimed at reducing soil nutrient availability, on arbuscular mycorrhizal colonization. Seedlings of 27 plant species with different sets of life-history traits (functional group affiliation, life history strategy and nitrophilic status) were grown in pots filled with soil from a nutrient-rich set-aside field and amended with different amounts of C. Mycorrhizal colonization was progressively reduced along the gradient of increasing C addition in 17 out of 27 species, but not in the remaining species. Grasses had lower colonization levels than forbs and legumes and the decline in AM fungal colonization was more pronounced in legumes than in other forbs and grasses. Mycorrhizal colonization did not differ between annual and perennial species, but decreased more rapidly along the gradient of increasing C addition in plants with high Ellenberg N values than in plants with low Ellenberg N values. Soil C addition not only limits plant growth through a reduction in available nutrients, but also reduces mycorrhizal colonization of plant roots. The effect of C addition on mycorrhizal colonization varies among plant functional groups, with legumes experiencing an overproportional reduction in AM fungal colonization along the gradient of increasing C addition. We therefore propose that for a better understanding of vegetation succession on set-aside fields one may consider the interrelationship between plant growth, soil nutrient availability and mycorrhizal colonization of plant roots.

  17. Multi-omics approach identifies molecular mechanisms of plant-fungus mycorrhizal interaction

    Directory of Open Access Journals (Sweden)

    Peter E Larsen

    2016-01-01

    Full Text Available In mycorrhizal symbiosis, plant roots form close, mutually beneficial interactions with soil fungi. Before this mycorrhizal interaction can be established however, plant roots must be capable of detecting potential beneficial fungal partners and initiating the gene expression patterns necessary to begin symbiosis. To predict a plant root – mycorrhizal fungi sensor systems, we analyzed in vitro experiments of Populus tremuloides (aspen tree and Laccaria bicolor (mycorrhizal fungi interaction and leveraged over 200 previously published transcriptomic experimental data sets, 159 experimentally validated plant transcription factor binding motifs, and more than 120-thousand experimentally validated protein-protein interactions to generate models of pre-mycorrhizal sensor systems in aspen root. These sensor mechanisms link extracellular signaling molecules with gene regulation through a network comprised of membrane receptors, signal cascade proteins, transcription factors, and transcription factor biding DNA motifs. Modeling predicted four pre-mycorrhizal sensor complexes in aspen that interact with fifteen transcription factors to regulate the expression of 1184 genes in response to extracellular signals synthesized by Laccaria. Predicted extracellular signaling molecules include common signaling molecules such as phenylpropanoids, salicylate, and, jasmonic acid. This multi-omic computational modeling approach for predicting the complex sensory networks yielded specific, testable biological hypotheses for mycorrhizal interaction signaling compounds, sensor complexes, and mechanisms of gene regulation.

  18. Some Root Traits of Barley (Hordeum vulgare L. as Affected by Mycorrhizal Symbiosis under Drought Stress

    Directory of Open Access Journals (Sweden)

    R. Bayani

    2016-05-01

    Full Text Available The effect of drought stress and mycorrhizal symbiosis on the colonization, root and leaf phosphorous content, root and leaf phosphatase activity, root volume and area as well as shoot dry weight of a variety of hulless barley were evaluated using a completely randomized experimental design (CRD with 3 replications. Treatments were three levels of drought stress of 30, 60 and 90% field capacity and two levels of mycorrhizal with and without inoculation. According to the results, the highest value of leaf phosphorous (1.54 mg/g was observed at mycorrhizal symbiosis against severe drought treatment. Root phosphatase activity was highest (297.9 OD min -1 FW-1 at severe drought stress with mycorrhizal symbiosis which in comparison with mild stress in the presence of mycorrhiza showed 16.6 fold increasing. The control and non-mycorrhizal symbiosis treatments had highest root dry weight (0.091 g. The lowest root volume (0.016 cm2 observed at mycorrhizal symbiosis × severe drought treatment. Generally, Inoculation of barley seed with mycorrhiza at severe water stress could transport more phosphorous to shoot, especially leaf via inducing of leaf and root phosphatase activity. Also, in addition to supply of nutrient sources especially phosphorous for plant, mycorrhizal symbiosis could play an important role in withstanding water stress in plant via increasing of root dry weight and area.

  19. The arbuscular mycorrhizal symbiosis influences sulfur starvation responses of Medicago truncatula.

    Science.gov (United States)

    Sieh, Daniela; Watanabe, Mutsumi; Devers, Emanuel A; Brueckner, Franziska; Hoefgen, Rainer; Krajinski, Franziska

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis is a mutualistic interaction that occurs between the large majority of vascular plants and fungi of the phylum Glomeromycota. In addition to other nutrients, sulfur compounds are symbiotically transferred from AM fungus to host plants; however, the physiological importance of mycorrhizal-mediated sulfur for plant metabolism has not yet been determined. We applied different sulfur and phosphate fertilization treatments to Medicago truncatula and investigated whether mycorrhizal colonization influences leaf metabolite composition and the expression of sulfur starvation-related genes. The expression pattern of sulfur starvation-related genes indicated reduced sulfur starvation responses in mycorrhizal plants grown at 1 mM phosphate nutrition. Leaf metabolite concentrations clearly showed that phosphate stress has a greater impact than sulfur stress on plant metabolism, with no demand for sulfur at strong phosphate starvation. However, when phosphate nutrition is high enough, mycorrhizal colonization reduces sulfur stress responses, probably as a result of symbiotic sulfur uptake. Mycorrhizal colonization is able to reduce sulfur starvation responses in M. truncatula when the plant's phosphate status is high enough that sulfur starvation is of physiological importance. This clearly shows the impact of mycorrhizal sulfur transfer on plant metabolism. © 2012 Max-Planck Society New Phytologist © 2012 New Phytologist Trust.

  20. Effect of phosphate and the arbuscular mycorrhizal fungus Glomus intraradices on disease severity of root rot of peas ( Pisum sativum ) caused by Aphanomyces euteiches

    DEFF Research Database (Denmark)

    Bødker, Lars; Kjøller, Rasmus; Rosendahl, Søren

    1998-01-01

    The effects of inorganic phosphate levels and the presence of arbuscular mycorrhiza on disease severity of Aphanomyces euteiches in pea roots were studied. Disease severity on roots and epicotyl as well as the oospore number within infected root tissue were correlated with the phosphorus (P) level...... in the growth medium. The arbuscular mycorrhizal fungus Glomus intraradices increased P uptake and the P concentration in the plant but reduced disease development in peas. Polyacrylamide gel electrophoresis followed by densitometry of glucose-6-phosphate dehydrogenase specific to A.euteiches was used...

  1. Functional and genetic diversity of mycorrhizal fungi from single plants of Caladenia formosa (Orchidaceae)

    Science.gov (United States)

    Huynh, Tien T.; Thomson, Richard; Mclean, Cassandra B.; Lawrie, Ann C.

    2009-01-01

    Background and Aims Mycorrhizal associations are essential to the plant kingdom. The largest flowering plant family, the Orchidaceae, relies on mycorrhizal fungi for germination, growth and survival. Evidence suggests varying degrees of fungal-host specificity based on a single fungal isolate from a single plant. This paper shows for the first time the diversity of endophytes colonizing in a single plant over consecutive years and the functional significance of this diversity. Methods Stem-collars of Caladenia formosa were collected in different seasons and years. Mycorrhizal fungi isolated were tested for their efficacy to induce leafing and genetically determined using ITS-RFLP and sequencing. Results Multiple mycorrhizal fungi were repeatedly isolated from a single collar that displayed varying effectiveness in germination percentages and adult leaf length. Additional factors contributed to the isolation of effective mycorrhizal fungi; fungal collection season, year of collection and individual isolates. Surface sterilization only improved the number of isolated mycorrhizal fungi. Dual inoculation did not increase germination. All 59 mycorrhizal fungi effective in germinating seed belonged to one clearly defined ITS (internal transcribed spacer) clade and clustered close to Sebacina vermifera (79–89 % homology). Isolates resulting in the greatest germination were not necessarily those resulting in the greatest survival and growth 1 year after germination. Conclusion Single orchid plants contained multiple mycorrhizal fungal strains of one species that had diverse functional differences. These results suggest that our current knowledge of fungal–host specificity may be incomplete due to experimental and analytical limitations. It also suggests that the long-term effectiveness of a mycorrhizal fungus or fungi could only be found by germination and longer-term growth tests rather than genetically. PMID:19561011

  2. Monitoring CO2emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, Martin; Jansa, Jan

    2017-01-01

    Quantification of carbon (C) fluxes in mycorrhizal plants is one of the important yet little explored tasks of mycorrhizal physiology and ecology. 13 CO 2 pulse-chase labelling experiments are increasingly being used to track the fate of C in these plant-microbial symbioses. Nevertheless, continuous monitoring of both the below- and aboveground CO 2 emissions remains a challenge, although it is necessary to establish the full C budget of mycorrhizal plants. Here, a novel CO 2 collection system is presented which allows assessment of gaseous CO 2 emissions (including isotopic composition of their C) from both belowground and shoot compartments. This system then is used to quantify the allocation of recently fixed C in mycorrhizal versus nonmycorrhizal Medicago truncatula plants with comparable biomass and mineral nutrition. Using this system, we confirmed substantially greater belowground C drain in mycorrhizal versus nonmycorrhizal plants, with the belowground CO 2 emissions showing large variation because of fluctuating environmental conditions in the glasshouse. Based on the assembled 13 C budget, the C allocation to the mycorrhizal fungus was between 2.3% (increased 13 C allocation to mycorrhizal substrate) and 2.9% (reduction of 13 C allocation to mycorrhizal shoots) of the plant gross photosynthetic production. Although the C allocation to shoot respiration (measured during one night only) did not differ between the mycorrhizal and nonmycorrhizal plants under our experimental conditions, it presented a substantial part (∼10%) of the plant C budget, comparable to the amount of CO 2 released belowground. These results advocate quantification of both above- and belowground CO 2 emissions in future studies.

  3. The role of mycorrhizal fungi in integrated carbon and nitrogen cycles

    Science.gov (United States)

    Rebel, Karin; Phillips, Rich; Fransson, Petra; Brzostek, Eddie; Wassen, Martin

    2013-04-01

    Understanding the role of terrestrial ecosystems in removing carbon dioxide (CO2) from the atmosphere remains one of the fundamental challenges to predicting future changes in the Earth's climate. Will forests continue to sequester carbon (C) under rising atmospheric CO2 and nitrogen (N) deposition, or will the capacity of trees to build new biomass be constrained by lack of nutrients? Recent research shows that not all tree species react similarly to N-deposition; differences are found in growth rates, survival and C-storage. Mycorrhizal fungi are an important link in coupling the C and N cycles and are critical for tree growth. Mycorrhizal fungi form mutualistic relationships, receiving carbohydrates from their plant hosts and in return enhancing the supply of critical nutrients. The two most abundant mycorrhizal associations are arbuscular mycorrhizae (AM) and ectomycorrhizae (EM), both having different mechanisms of N acquisition, which may explain observed differences in tree species response to N-deposition. Changing environmental variables influence mycorrhizal fungi. Increasing CO2 concentration increases mycorrhizal abundance, growth and plant C allocation belowground. However, the effect of N-deposition on mycorrhizae is less clear. N-deposition can have positive, neutral or negative effects on mycorrhizal abundance and growth. It has been hypothesized that the effect of N-deposition on mycorrhizal growth depends on initial soil nutrient status. This soil nutrient status may also determine the nature of the mycorrhizal relationship to the tree, where in nutrient poor conditions, they could be more beneficial than in nutrient rich conditions. In this research, we extend the hypothesis to include growth of trees associated with either EM or AM, as a function of increasing nitrogen deposition and soil nutrient status. Therefore, we take into account the C-cost and the N-gain of the mycorrhizal fungi for the tree in the different nutrient stages.

  4. Role of Arbuscular Mycorrhizal Fungi on Iris

    Directory of Open Access Journals (Sweden)

    CHEN Yuan

    2014-06-01

    Full Text Available For efficiency using the amphibious plant iris to restore polluted water, the promoting effect of different arbuscular mycorrhiza fungi(AMFon iris was investigated, by monitoring the plant growth index, the physicochemical properties of the soil and the plant photosynthesis indexes. The result showed that the promoting effects of the AMF on the aboveground part and the underground part of the iris were based on different mechanism. For the underground part of the iris, the AMF stimulated its growth through the nutrient enrichment which was performed by the enormous hypha network. The nitrogen absorbing rate of the G. mosseae and the G. intraradices infected iris increased about 71.75% and 42.55%, and the phosphorous absorbing rate increased 8.36% and 9.5% separately. For the aboveground part of the iris, the AMF strengthened the conductance of the leaves’ stomas to control the balance between the net photosynthesis rate and the transpiration rate, so that the utilization rate of water resources was optimized, the metabolic rate was accelerated and the growth of the plant was promoted eventually. In this study, the promoting effect of the G. mosseae on the photosynthesis rate of the iris was significantly better than that of the G. intraradices(P<0.05.

  5. A biological market analysis of the plant-mycorrhizal symbiosis.

    Science.gov (United States)

    Wyatt, Gregory A K; Kiers, E Toby; Gardner, Andy; West, Stuart A

    2014-09-01

    It has been argued that cooperative behavior in the plant-mycorrhizal mutualism resembles trade in a market economy and can be understood using economic tools. Here, we assess the validity of this "biological market" analogy by investigating whether a market mechanism--that is, competition between partners over the price at which they provide goods--could be the outcome of natural selection. Then, we consider the conditions under which this market mechanism is sufficient to maintain mutualistic trade. We find that: (i) as in a market, individuals are favored to divide resources among trading partners in direct relation to the relative amount of resources received, termed linear proportional discrimination; (ii) mutualistic trade is more likely to be favored when individuals are able to interact with more partners of both species, and when there is a greater relative difference between the species in their ability to directly acquire different resources; (iii) if trade is favored, then either one or both species is favored to give up acquiring one resource directly, and vice versa. We then formulate testable predictions as to how environmental changes and coevolved responses of plants and mycorrhizal fungi will influence plant fitness (crop yields) in agricultural ecosystems. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  6. Phylogenetic constrains on mycorrhizal specificity in eight Dendrobium (Orchidaceae) species.

    Science.gov (United States)

    Xing, Xiaoke; Ma, Xueting; Men, Jinxin; Chen, Yanhong; Guo, Shunxing

    2017-05-01

    Plant phylogeny constrains orchid mycorrhizal (OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species, and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota (9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.

  7. Metal accumulation and detoxification mechanisms in mycorrhizal Betula pubescens.

    Science.gov (United States)

    Fernández-Fuego, D; Bertrand, A; González, A

    2017-12-01

    Metal detoxification in plants is a complex process that involves different mechanisms, such as the retention of metals to the cell wall and their chelation and subsequent compartmentalization in plant vacuoles. In order to identify the mechanisms involved in metal accumulation and tolerance in Betula pubescens, as well as the role of mycorrhization in these processes, mycorrhizal and non-mycorrhizal plants were grown in two industrial soils with contrasting concentrations of heavy metals. Mycorrhization increased metal uptake at low metal concentrations in the soil and reduced it at high metal concentrations, which led to an enhanced growth and biomass production of the host when growing in the most polluted soil. Our results suggest that the sequestration on the cell wall is the main detoxification mechanism in white birch exposed to acute chronic metal-stress, while phytochelatins play a role mitigating metal toxicity inside the cells. Given its high Mn and Zn root-to-shoot translocation rate, Betula pubescens is a very promising species for the phytoremediation of soils polluted with these metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Mycorrhizal fungi increase coffee plants competitiveness against Bidens pilosa interference

    Directory of Open Access Journals (Sweden)

    André Cabral França

    2016-06-01

    Full Text Available Mycorrhizae provide several benefits to coffee plants. This study evaluated whether these benefits influence the damage caused by the Bidens pilosa competition with coffee seedlings. A randomized blocks design was used, with treatments established in a 2 x 3 factorial scheme (presence and absence of B. pilosa interference in non-inoculated control or plants inoculated with either Claroideoglomus etunicatum or Dentiscutata heterogama. Coffee seedlings were inoculated with fungi spores and developed for 120 days. Then, they were subjected to the interference of B. pilosa for more 120 days, when data were collected for growth traits, mycorrhizal colonization, dry matter and foliar nutrient concentrations in coffee plants. Dry matter and nutrient contents in B. pilosa plants were also evaluated. Inoculation provided better growth and nutrition of coffee plants. The competition with B. pilosa reduced mycorrhizal colonization, height, leaf area, leaf and stem dry mass, root dry weight, number of reproductive branches and levels of P and Fe in the coffee plants. However, the harmful effect of the interference was lower in inoculated coffee plants. The dry mass of B. pilosa decreased under the interference of inoculated coffee plants. The inoculation of C. etunicatum and D. heterogama in Arabica coffee seedlings increases the competitiveness of the crop against B. pilosa interference.

  9. DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Floss, Daniela S; Levy, Julien G; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J

    2013-12-17

    Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis.

  10. Experimental evidence of ericoid mycorrhizal potential within Serendipitaceae (Sebacinales).

    Science.gov (United States)

    Vohník, Martin; Pánek, Matěj; Fehrer, Judith; Selosse, Marc-André

    2016-11-01

    The Sebacinales are a monophyletic group of ubiquitous hymenomycetous mycobionts which form ericoid and orchid mycorrhizae, ecto- and ectendomycorrhizae, and nonspecific root endophytic associations with a wide spectrum of plants. However, due to the complete lack of fungal isolates derived from Ericaceae roots, the Sebacinales ericoid mycorrhizal (ErM) potential has not yet been tested experimentally. Here, we report for the first time isolation of a serendipitoid (formerly Sebacinales Group B) mycobiont from Ericaceae which survived in pure culture for several years. This allowed us to test its ability to form ericoid mycorrhizae with an Ericaceae host in vitro, to describe its development and colonization pattern in host roots over time, and to compare its performance with typical ErM fungi and other serendipitoids derived from non-Ericaceae hosts. Out of ten serendipitoid isolates tested, eight intracellularly colonized Vaccinium hair roots, but only the Ericaceae-derived isolate repeatedly formed typical ericoid mycorrhiza morphologically identical to ericoid mycorrhiza commonly found in naturally colonized Ericaceae, but yet different from ericoid mycorrhiza formed in vitro by the prominent ascomycetous ErM fungus Rhizoscyphus ericae. One Orchidaceae-derived isolate repeatedly formed abundant hyaline intracellular microsclerotia morphologically identical to those occasionally found in naturally colonized Ericaceae, and an isolate of Serendipita (= Piriformospora) indica produced abundant intracellular chlamydospores typical of this species. Our results confirm for the first time experimentally that some Sebacinales can form ericoid mycorrhiza, point to their broad endophytic potential in Ericaceae hosts, and suggest possible ericoid mycorrhizal specificity in Serendipitaceae.

  11. Early responses to Nod factors and mycorrhizal colonization in a non-nodulating Phaseolus vulgaris mutant.

    Science.gov (United States)

    Cárdenas, Luis; Alemán, Emilia; Nava, Noreide; Santana, Olivia; Sánchez, Federico; Quinto, Carmen

    2006-03-01

    Legumes can acquire nitrogen through a symbiotic interaction with rhizobial bacteria. The initiation of this process is determined by a molecular dialogue between the two partners. Legume roots exude flavonoids that induce the expression of the bacterial nodulation genes, which encode proteins involved in the synthesis and secretion of signals called Nod factors (NFs). NFs signal back to the plant root and trigger several responses, leading to bacterial invasion and nodule formation. Here, we describe the molecular and cellular characterization of a Phaseolus vulgaris non-nodulating mutant (NN-mutant). Root hair cells of the NN-mutant plant respond with swelling and branching when inoculated with Rhizobium etli, albeit without curling induction. Furthermore, neither initiation of cell division in the outer cortex, nor entrapment of bacteria nor infection thread formation was observed. Both the bean wild-type and the NN-mutant responded with elevated intracellular calcium changes in the root hairs. Although the NN-mutant is deficient in early nodulin gene expression when inoculated with R. etli, it can be effectively colonized by arbuscular mycorrhizal fungi (Glomus intraradices). Our data indicate that the P. vulgaris NN-mutant is not blocked at the NFs early perception stage, but at later downstream stages between Ca(2+) signaling and early nodulin induction. This supports the idea that both microsymbionts are perceived and trigger different downstream pathways in the host plant.

  12. Inoculant of arbuscular mycorrhizal fungi (Rhizophagus clarus increase yield of soybean and cotton under field conditions

    Directory of Open Access Journals (Sweden)

    Martha Viviana Torres Cely

    2016-05-01

    Full Text Available Nutrient availability is an important factor in crop production, and regular addition of chemical fertilizers is the most common practice to improve yield in agrosystems for intensive crop production. The use of some groups of microorganisms that have specific activity providing nutrients to plants is a good alternative, and arbuscular mycorrhizal fungi (AMF enhance plant nutrition by providing especially phosphorus (P, improving plant growth and increasing crop production. Unfortunately, the use of AMF as an inoculant on a large scale is not yet widely used, because of several limitations in obtaining a large amount of inoculum due to several factors, such as low growth, the few species domesticated under in vitro conditions, and high competition with native AMF. The objective of this work was to test the infectivity of a Rhizophagus clarus inoculum and its effectiveness as an alternative for P supply in soybean (Glycine max L. and cotton (Gossypium hirsutum L.. The experiments were carried out in plots and the treatments were: Fertilizer; AMF, AMF + Fertilizer and AMF + ½ Fertilizer; non-inoculated and non-fertilized plants were considered the control. The parameters evaluated were AMF root colonization and effect of inoculation on plant growth and yield under a field conditions. The results showed that AMF inoculation increased the effect of fertilizer application in soybean, and that in cotton R. clarus was more effective than chemical fertilizer

  13. Synergism and context dependency of interactions between arbuscular mycorrhizal fungi and rhizobia with a prairie legume.

    Science.gov (United States)

    Larimer, Anna L; Clay, Keith; Bever, James D

    2014-04-01

    Biotic interactions play primary roles in major theories of the distribution and abundance of species, yet the nature of these biotic interactions can depend upon the larger ecological community. Leguminous plants, for example, commonly associate with both arbuscular mycorrhizal fungi (AMF) and rhizobia bacteria, and the pairwise interactions may depend upon the presence or identity of the third partner. To determine if the dynamics of plant-AMF and plant-rhizobia interactions are affected by the alternate symbiont, we manipulated the presence and identity of each symbiont, as well as levels of the nutrients supplied by each symbiont (nitrogen and phosphorus), on the growth of prairie legume Amorpha canescens. We found strong synergistic effects of AMF and rhizobia inoculation on plant biomass production that were independent of nutrient levels. AMF and rhizobia responses were each influenced by the other, but not in the same direction. AMF infection increased root nodule number and mass, but rhizobia inoculation decreased AMF hyphal colonization of roots. The relative benefits of each combination of symbionts depended upon phosphorus level. The effect of nitrogen was also contingent on the biotic environment where nitrogen addition decreased nodulation, but this decrease was reduced with coinfection by AMF. Our results demonstrate a strong contingency on the co-occurrence of AMF and rhizobia for the long-term fitness of A. canescens, and suggest that the belowground community is critical for the success of this species in tallgrass prairies.

  14. Effects of Pseudomonas fluorescens on the Water Parameters of Mycorrhizal and Non-Mycorrhizal Seedlings of Pinus halepensis

    Directory of Open Access Journals (Sweden)

    José A. Saiz de Omeñaca

    2013-08-01

    Full Text Available Inoculation of forest seedlings with mycorrhizal fungi and rhizobacteria can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. In this paper, under standard nursery conditions, Aleppo pine seedlings were inoculated with Pseudomonas fluorescens CECT 5281 rhizobacteria. Some of these seedlings were also inoculated with the ectomycorrhizal fungus Pisolithus tinctorius. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [Emax], mycorrhizal colonisation, and concentration of macronutrients (N, P, K, Ca and Mg in the seedlings. Subsequently, a trial was conducted to assess the root growth potential. P. fluorescens CECT 5281 decreased the cellular osmotic potential of P. halepensis seedlings but increased its elasticity. P. tinctorius + P. fluorescens caused osmotic adjustment at zero turgor and increased tissue elasticity, which improved tolerance to water stress. All inoculations improved the growth and nutrition of the seedlings but caused non-significant effects on root growth potential. The co-inoculation Pisolithus tinctorius + Pseudomonas fluorescens at the nursery may be a suitable technique for producing improved seedling material for restoration purposes.

  15. Two Medicago truncatula Half-ABC Transporters Are Essential for Arbuscule Development in Arbuscular Mycorrhizal Symbiosis

    National Research Council Canada - National Science Library

    Quan Zhang; Laura A. Blaylock; Maria J. Harrison

    2010-01-01

    In the symbiotic association of plants and arbuscular mycorrhizal (AM) fungi, the fungal symbiont resides in the root cortical cells where it delivers mineral nutrients to its plant host through branched hyphae called arbuscules...

  16. Arbuscular mycorrhizal fungi counteract the Janzen-Connell effect of soil pathogens

    NARCIS (Netherlands)

    Liang, Minxia; Liu, Xubing; Etienne, Rampal S; Huang, Fengmin; Wang, Yongfan; Yu, Shixiao

    Soilborne pathogens can contribute to diversity maintenance in tree communities through the Janzen-Connell effect, whereby the pathogenic reduction of seedling performance attenuates with distance from conspecifics. By contrast, arbuscular mycorrhizal fungi (AMF) have been reported to promote

  17. Arbuscular Mycorrhizal Fungus Alleviates Chilling Stress by Boosting Redox Poise and Antioxidant Potential of Tomato Seedlings

    NARCIS (Netherlands)

    Liu, Airong; Chen, Shuangchen; Wang, Mengmeng; Liu, Dilin; Chang, Rui; Wang, Zhonghong; Lin, Xiaomin; Bai, Bing; Ahammed, Golam Jalal

    2016-01-01

    The universal symbiotic associations between arbuscular mycorrhizal fungi (AMF) and plant roots remarkably stimulate plant growth, nutrient uptake, and stress responses. The present study investigated the stress ameliorative potential of the AM fungus Funneliformis mosseae against chilling in

  18. Saprotrophic fungal mycorrhizal symbionts in achlorophyllous orchids: finding treasures among the 'molecular scraps'?

    Science.gov (United States)

    Selosse, Marc-André; Martos, Florent; Perry, Brian A; Padamsee, Mahajabeen; Roy, Mélanie; Pailler, Thierry

    2010-04-01

    Mycoheterotrophic plants are achlorophyllous plants that obtain carbon from their mycorrhizal fungi. They are usually considered to associate with fungi that are (1) specific of each mycoheterotrophic species and (2) mycorrhizal on surrounding green plants, which are the ultimate carbon source of the entire system. Here we review recent works revealing that some mycoheterotrophic plants are not fungal-specific, and that some mycoheterotrophic orchids associate with saprophytic fungi. A re-examination of earlier data suggests that lower specificity may be less rare than supposed in mycoheterotrophic plants. Association between mycoheterotrophic orchids and saprophytic fungi arose several times in the evolution of the two partners. We speculate that this indirectly illustrates why transition from saprotrophy to mycorrhizal status is common in fungal evolution. Moreover, some unexpected fungi occasionally encountered in plant roots should not be discounted as 'molecular scraps', since these facultatively biotrophic encounters may evolve into mycorrhizal symbionts in some other plants.

  19. Mycorrhizal fungi associated with Taiwanese Pyrola morrisonensis (Ericaceae in a naturally regenerated forest

    Directory of Open Access Journals (Sweden)

    Yosuke MATSUDA

    2017-11-01

    Full Text Available Pyrola morrisonensis, an evergreen herb in the family Ericaceae, is endemic to Taiwan. We examined mycorrhizal development and the associated fungi in this species. Nine plants were collected in a naturally regenerated forest in central Taiwan. The plants were genetically identical in their internal transcribed spacer (ITS region, and their sequences matched the known sequence for P. morrisonensis. Fine roots of each plant were colonized by mycorrhizal fungi that formed mycorrhizas either with or without fungal mantles. DNA sequences of the ITS region of these fungi suggested that they belonged to mycorrhizal taxa that are common tree symbionts. Among them, members of Thelephoraceae were the dominant taxon in the host plants. These results indicate that P. morrisonensis is intimately associated with mycorrhizal fungi that might also connect with neighboring trees.

  20. Plant-soil feedbacks and mycorrhizal type influence temperate forest population dynamics.

    Science.gov (United States)

    Bennett, Jonathan A; Maherali, Hafiz; Reinhart, Kurt O; Lekberg, Ylva; Hart, Miranda M; Klironomos, John

    2017-01-13

    Feedback with soil biota is an important determinant of terrestrial plant diversity. However, the factors regulating plant-soil feedback, which varies from positive to negative among plant species, remain uncertain. In a large-scale study involving 55 species and 550 populations of North American trees, the type of mycorrhizal association explained much of the variation in plant-soil feedbacks. In soil collected beneath conspecifics, arbuscular mycorrhizal trees experienced negative feedback, whereas ectomycorrhizal trees displayed positive feedback. Additionally, arbuscular mycorrhizal trees exhibited strong conspecific inhibition at multiple spatial scales, whereas ectomycorrhizal trees exhibited conspecific facilitation locally and less severe conspecific inhibition regionally. These results suggest that mycorrhizal type, through effects on plant-soil feedbacks, could be an important contributor to population regulation and community structure in temperate forests. Copyright © 2017, American Association for the Advancement of Science.

  1. Phylogenetic and microsatellite markers for Tulasnella (Tulasnellaceae) mycorrhizal fungi associated with Australian orchids.

    Science.gov (United States)

    Ruibal, Monica P; Peakall, Rod; Smith, Leon M; Linde, Celeste C

    2013-03-01

    Phylogenetic and microsatellite markers were developed for Tulasnella mycorrhizal fungi to investigate fungal species identity and diversity. These markers will be useful in future studies investigating the phylogenetic relationship of the fungal symbionts, specificity of orchid-mycorrhizal associations, and the role of mycorrhizae in orchid speciation within several orchid genera. • We generated partial genome sequences of two Tulasnella symbionts originating from Chiloglottis and Drakaea orchid species with 454 genome sequencing. Cross-genus transferability across mycorrhizal symbionts associated with multiple genera of Australian orchids (Arthrochilus, Chiloglottis, Drakaea, and Paracaleana) was found for seven phylogenetic loci. Five loci showed cross-transferability to Tulasnella from other orchid genera, and two to Sebacina. Furthermore, 11 polymorphic microsatellite loci were developed for Tulasnella from Chiloglottis. • Highly informative markers were obtained, allowing investigation of mycorrhizal diversity of Tulasnellaceae associated with a wide variety of terrestrial orchids in Australia and potentially worldwide.

  2. Insights on the Impact of Arbuscular Mycorrhizal Symbiosis on Tomato Tolerance to Water Stress

    National Research Council Canada - National Science Library

    Chitarra, Walter; Pagliarani, Chiara; Maserti, Biancaelena; Lumini, Erica; Siciliano, Ilenia; Cascone, Pasquale; Schubert, Andrea; Gambino, Giorgio; Balestrini, Raffaella; Guerrieri, Emilio

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development...

  3. Growth and nutrition of eucalyptus clones seedlings inoculated with mycorrhizal fungi

    National Research Council Canada - National Science Library

    Francisco deSousa Lima; Carla daSilva Sousa

    2014-01-01

    ... (five fungal species and five eucalyptus clones), with five replications. In general, the mycorrhizal symbiosis significantly increased the growth and nutrition of eucalyptus seedlings, when compared to the non-inoculated seedlings...

  4. Effects of Microbiotic Soil Crust Organisms and Mycorrhizal Fungi on Seedling Growth of Blackbrush (Coleogyne ramosissima)

    National Research Council Canada - National Science Library

    Pendleton, Rosemary

    1999-01-01

    .... A series of experiments conducted from 1993 to 1997 tested the effect of inoculation with arbuscular mycorrhizal fungi on the growth of young blackbrush seedlings under a variety of soil nutrient conditions...

  5. Effects of ammonium and nitrate on mycorrhizal seedlings of Pinus sylvestris.

    NARCIS (Netherlands)

    Termorshuizen, A.J.; Ket, P.C.

    1991-01-01

    The effects of ammonium sulphate and sodium nitrate on Pinus sylvestris seedlings inoculated with Paxillus involutus and Suillus bovinus were investigated. Weekly fertilization (26 weeks) positively affected the plant dry weight, but inhibited the mycorrhizal formation and decreased the root

  6. Phylogenetic and Microsatellite Markers for Tulasnella (Tulasnellaceae Mycorrhizal Fungi Associated with Australian Orchids

    Directory of Open Access Journals (Sweden)

    Monica P. Ruibal

    2013-03-01

    Full Text Available Premise of the study: Phylogenetic and microsatellite markers were developed for Tulasnella mycorrhizal fungi to investigate fungal species identity and diversity. These markers will be useful in future studies investigating the phylogenetic relationship of the fungal symbionts, specificity of orchid–mycorrhizal associations, and the role of mycorrhizae in orchid speciation within several orchid genera. Methods and Results: We generated partial genome sequences of two Tulasnella symbionts originating from Chiloglottis and Drakaea orchid species with 454 genome sequencing. Cross-genus transferability across mycorrhizal symbionts associated with multiple genera of Australian orchids (Arthrochilus, Chiloglottis, Drakaea, and Paracaleana was found for seven phylogenetic loci. Five loci showed cross-transferability to Tulasnella from other orchid genera, and two to Sebacina. Furthermore, 11 polymorphic microsatellite loci were developed for Tulasnella from Chiloglottis. Conclusions: Highly informative markers were obtained, allowing investigation of mycorrhizal diversity of Tulasnellaceae associated with a wide variety of terrestrial orchids in Australia and potentially worldwide.

  7. Mycorrhizal diversity in the rhizosphere of sugarcane and grass on different soil types

    Science.gov (United States)

    Ratri Cahyani, Vita; Rastikawati, Dewi; Yuniardi, Nestri; Syamsiyah, Jauhari; Suntoro

    2017-11-01

    Mycorrhiza has been known well as beneficial microbiota for supporting plant growth and production. Understanding of the variability and the consistency of the mycorrhizal diversity on various habitats is important for developing mycorrhizal utilization. Mycorrhizal diversity in the rhizosphere of sugarcane from 4 (four) soil types and the rhizosphere of grass from 3 (three) soil types were investigated in the present study. The results showed that Glomus indicated as a versatile genus because it was found as a common and dominant genus in the sugarcane rhizosphere on all of four soil types (Alfisol, Andisol, Inceptisol, Vertisol) and in the grass rhizosphere on all of three soil types (Ultisol, Oxisol, Histosol). In addition, Acaulospora was found as a common genus in grass rhizosphere. Statistical analysis indicated that P availability in the rhizosphere of sugarcane had a significantly negative correlation with mycorrhizal spore density, in which decreasing P availability significantly related with increasing spore density.

  8. The Lotus japonicus MAMI gene links root development, arbuscular mycorrhizal symbiosis and phosphate availability.

    Science.gov (United States)

    Volpe, Veronica; Dell'Aglio, Elisa; Bonfante, Paola

    2013-03-01

    The arbuscular mycorrhizal-induced LjMAMI gene is phylogenetically related to GARP transcription factors involved in Pi-starvation responses such as AtPHR1. The gene is strongly upregulated in arbusculated cells from mycorrhizal plants and in root meristems, irrespectively of the fungal presence. A further expression analysis revealed a similar expression pattern for LjPT4, considered a marker gene for mycorrhizal functionality. Here we show that the LjPT4 promoter contains two conserved cis-acting elements typically found in Pi-starvation induced Pi transporters. One of these is strongly related to the binding site of AtPHR1, suggesting a direct regulation of LjPT4 by LjMAMI. The expression of both genes in non-mycorrhizal tissues leads to the hypothesis that these symbiosis-inducible genes are also involved in Pi starvation responses in root meristems in an AM-independent manner.

  9. Carbon availability triggers fungal nitrogen uptake and transport in arbuscular mycorrhizal symbiosis

    National Research Council Canada - National Science Library

    Carl R. Fellbaum; Emma W. Gachomo; Yugandhar Beesetty; Sulbha Choudhari; Gary D. Strahan; Philip E. Pfeffer; E. Toby Kiers; Heike Bücking

    2012-01-01

    The arbuscular mycorrhizal (AM) symbiosis, formed between the majority of land plants and ubiquitous soil fungi of the phylum Glomeromycota, is responsible for massive nutrient transfer and global carbon sequestration...

  10. The Laccaria and Tuber Genomes Reveal Unique Signatures of Mycorrhizal Symbiosis Evolution (2010 JGI User Meeting)

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Steve

    2010-03-24

    Francis Martin from the French agricultural research institute INRA talks on how "The Laccaria and Tuber genomes reveal unique signatures of mycorrhizal symbiosis evolution" on March 24, 2010 at the 5th Annual DOE JGI User Meeting

  11. Mycorrhizal diversity in Apostasia (Orchidaceae) indicates the origin and evolution of orchid mycorrhiza

    National Research Council Canada - National Science Library

    Yukawa, Tomohisa; Ogura-Tsujita, Yuki; Shefferson, Richard P; Yokoyama, Jun

    2009-01-01

    ... University, Yamagata 990-8560 Japan ABSTRACT We demonstrated that "orchid mycorrhiza," a specialized mycorrhizal type, appeared in the common ancestor of the largest plant family Orchidaceae and that the...

  12. The effect of elevated atmospheric CO{sub 2} on interactions between plant roots, arbuscular-mycorrhizal and pathogenic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Rillig, M.C.; Klironomos, J.N.; Allen, M.F. [San Diego State Univ., CA (United States)] [and others

    1995-09-01

    Of all effects of elevated atmospheric CO{sub 2} on plants and ecosystems, the least is known about plant rhizosphere responses. Rhizosphere fungi are fed primarily by root-derived substrates, and fulfill functions such as immobilization, decomposition, pathogeneity, and improvement of plant nutrition. This study describes the effect of elevated CO{sub 2} on the interaction between the pathogen Fusarium solani and the AM fungus Glomus intraradices in the rhizosphere of Artemisia tridentata. We measured intraradical infection and extraradical growth by the two fungi under elevated and ambient CO{sub 2} concentrations. We found a strong interaction between the two fungi. Root infection by and extraradical hyphal length of solani did not differ significantly between CO{sub 2} treatments in the presence of G. intraradices. In the absence of G. intraradices, however, infection by F. solani and its extraradical hyphal length increased under elevated CO{sub 2}. Our results indicate that pathogenic fungi do respond to elevated CO{sub 2} by increased hyphal growth and root infection (potential response), but also show that mycorrhizal fungi can profit more from the new conditions and serve to suppress the pathogen.

  13. Influence of silver and titanium nanoparticles on arbuscular mycorrhizal colonization and accumulation of radiocaesium in Helianthus annuus

    Energy Technology Data Exchange (ETDEWEB)

    Dubchak, S.; Ogar, A.; Mietelski, J. W.; Turnau, K.

    2010-07-01

    The influence of albacore's mycorrhizal fungus on {sup 1}34Cs uptake by Helianthus annuus was studied in a pilot study under growth chamber conditions. Mycorrhizal plants took up five times more {sup 1}34Cs (up to 250,000 Bq kg{sup -}1 dry weight) than non mycorrhizal plants. Silver and titanium nanoparticles, supplied into the surface soil layer decreased both the mycorrhizal colonization and Cs uptake by mycorrhizal plants. The application of activated carbon attenuated the effect of nanoparticles and increased {sup 1}34Cs uptake in the presence of mycorrhizal fungi (up to 400,000 Bq kg{sup -}1 dry weight). The results underline the possible application of phyto remediation techniques based on mycorrhizas assisted plants in decontamination of both radionuclides and nanoparticles. (Author) 27 refs.

  14. Mycorrhizal fungi influence on silver uptake and membrane protein gene expression following silver nanoparticle exposure

    Energy Technology Data Exchange (ETDEWEB)

    Noori, Azam [State University of New York, College of Environmental Science and Forestry (United States); White, Jason C. [Connecticut Agricultural Experiment Station (United States); Newman, Lee A., E-mail: lanewman@esf.edu [State University of New York, College of Environmental Science and Forestry (United States)

    2017-02-15

    The rapid growth of nanotechnology and the high demand for nanomaterial use have greatly increased the risk of particle release into the environment. Understanding nanomaterial interactions with crop species and their associated microorganisms is critical to food safety and security. In the current study, tomato was inoculated with mycorrhizal fungi and subsequently exposed to 12, 24, or 36 mg/kg of 2- or 15-nm silver nanoparticles (Ag-NPs). Mycorrhizal (M) and non-mycorrhizal (NM) tomatoes exposed to 36 mg/kg of 2-nm Ag-NPs accumulated 1300 and 1600 μg/g silver in their tissues, respectively. Mycorrhizal plants accumulated 14% less silver compared to non-mycorrhizal plants. To begin to understand the mechanisms by which plants accumulate NPs, the expression of two aquaporin channel genes, the plasma membrane intrinsic protein (PIP) and the tonoplast membrane intrinsic protein (TIP), and one potassium channel (KC) gene were studied. In non-mycorrhizal plants, the expression of KC, PIP, and TIP was eight, five, and nine times higher than the control, respectively. These expressions for mycorrhizal plants were 5.8, 3.5, and 2 times higher than controls, respectively. The expression of KC and PIP, which are located on the plasma membrane, was 3.5 and 2.5, respectively, times higher than TIP, which is located on the tonoplast. PIP expression was significantly higher in NM tomatoes exposed to 12 mg/kg of 2-nm Ag-NPs compared to M plants. These results show that mycorrhizal colonization decreases Ag accumulation in NP-exposed plants and also moderates changes in expression level of membrane transport proteins.

  15. Dioecious species and arbuscular mycorrhizal symbioses: The case of Antennaria dioica

    OpenAIRE

    Vega-Frutis, Rocío; Varga, Sandra; Kytöviita, Minna-Maarit

    2013-01-01

    Sex-specific interactions with herbivores and pollinators have been observed in female and male plants of dioecious species. However, only a limited number of studies have revised sex-specific patterns in mycorrhizal symbiosis. To test whether female and male plants of Antennaria dioica differ in their relationship with arbuscular mycorrhizal (AM) fungi, we examined the temporal and spatial variation in AM fungi in female, male and non-reproductive A. dioica plants in three natural population...

  16. Seasonal Dynamics of Arbuscular Mycorrhizal Fungal Communities in Roots in a Seminatural Grassland▿ †

    OpenAIRE

    Santos-González, Juan C.; Finlay, Roger D.; Tehler, Anders

    2007-01-01

    Symbiotic arbuscular mycorrhizal fungi (AMF) have been shown to influence both the diversity and productivity of grassland plant communities. These effects have been postulated to depend on the differential effects of individual mycorrhizal taxa on different plant species; however, so far there are few detailed studies of the dynamics of AMF colonization of different plant species. In this study, we characterized the communities of AMF colonizing the roots of two plant species, Prunella vulga...

  17. Mycorrhizal status of an ozone-sensitive poplar clone treated with the antiozonant ethylene diurea

    OpenAIRE

    Katanić, Marina; Paoletti, Elena; Orlović, Saša; Grebenc, Tine; Kraigher, Hojka

    2014-01-01

    The antiozonant ethylene diurea is proven to prevent growth reductions in forest trees induced by ozone. The community of mycorrhizal fungi could be useful indicator of environmental stress. In this study, response of mycorrhizal fungi and fine roots to a 4-year exposure to ambient ozone and treatment with antiozonant was investigated in ozone-sensitive poplar clone under field conditions. The community of ectomycorrhizal fungi and root length colonization with ectomycorrhizal, arbuscular myc...

  18. Growth response of different species of Ziziphus to inoculation with arbuscular mycorrhizal fungi

    OpenAIRE

    Thioye, B.; Mania, S.; Kane, A.; Ndiaye, C.; Soule, A. O.; Falls, D.; Duponnois, Robin; Sylla, S. N.; Ba, A. M.

    2017-01-01

    Introduction - Many of species of Ziziphus are underutilized crops despite their potential interests in agroforestry systems. Except for Ziziphus mauritiana, the effectiveness of arbuscular mycorrhizal fungi (AMF) on growth and mineral nutrition of Ziziphus spp. is not known. The aim of our study was to evaluate the mycorrhizal dependency (MD) of Ziziphus spp. in greenhouse conditions. [br/] Materials and methods - Three isolates of AMF were used: Rhizophagus irregularis isolate IR27, Funn...

  19. Mycorrhizal fungi influence on silver uptake and membrane protein gene expression following silver nanoparticle exposure

    Science.gov (United States)

    Noori, Azam; White, Jason C.; Newman, Lee A.

    2017-02-01

    The rapid growth of nanotechnology and the high demand for nanomaterial use have greatly increased the risk of particle release into the environment. Understanding nanomaterial interactions with crop species and their associated microorganisms is critical to food safety and security. In the current study, tomato was inoculated with mycorrhizal fungi and subsequently exposed to 12, 24, or 36 mg/kg of 2- or 15-nm silver nanoparticles (Ag-NPs). Mycorrhizal (M) and non-mycorrhizal (NM) tomatoes exposed to 36 mg/kg of 2-nm Ag-NPs accumulated 1300 and 1600 μg/g silver in their tissues, respectively. Mycorrhizal plants accumulated 14% less silver compared to non-mycorrhizal plants. To begin to understand the mechanisms by which plants accumulate NPs, the expression of two aquaporin channel genes, the plasma membrane intrinsic protein (PIP) and the tonoplast membrane intrinsic protein (TIP), and one potassium channel (KC) gene were studied. In non-mycorrhizal plants, the expression of KC, PIP, and TIP was eight, five, and nine times higher than the control, respectively. These expressions for mycorrhizal plants were 5.8, 3.5, and 2 times higher than controls, respectively. The expression of KC and PIP, which are located on the plasma membrane, was 3.5 and 2.5, respectively, times higher than TIP, which is located on the tonoplast. PIP expression was significantly higher in NM tomatoes exposed to 12 mg/kg of 2-nm Ag-NPs compared to M plants. These results show that mycorrhizal colonization decreases Ag accumulation in NP-exposed plants and also moderates changes in expression level of membrane transport proteins.

  20. The mycorrhizal type governs root exudation and nitrogen uptake of temperate tree species.

    Science.gov (United States)

    Liese, Rebecca; Lübbe, Torben; Albers, Nora W; Meier, Ina C

    2017-11-08

    Even though the two dominant mycorrhizal associations of temperate tree species differentially couple carbon (C) and nitrogen (N) cycles in temperate forests, systematic differences between the biogeochemical cycles of arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree species remain poorly described. A classification according to the mycorrhizal type offers the chance, though, to develop a global frame concept for the prediction of temperate ecosystem responses to environmental change. Focusing on the influence of mycorrhizal types on two key plant processes of biogeochemical cycling (root exudation and N acquisition), we investigated four temperate deciduous tree species per mycorrhizal type in a drought experiment in large mesocosms. We hypothesized that (H1) C loss by root exudation is higher in ECM than in AM trees, (H2) drought leads to higher reductions in root exudation of drought-sensitive ECM trees and (H3) inorganic N uptake is higher in AM than in ECM trees. In contradiction to H2, we found no systematic difference in root exudation between the mycorrhizal types at ample soil moisture, but almost twofold higher exudation in ECM trees when exposed to soil drought. In addition, photosynthetic C cost of root exudation strongly increased by ~10-fold in drought-treated ECM trees, while it only doubled in AM trees, which confirms H1. With respect to H3, we corroborated that AM trees had higher absolute and relative inorganic N acquisition rates than ECM trees, while the organic N uptake did not differ between mycorrhizal types. We conclude that ECM trees are less efficient in inorganic N uptake than AM trees, but ECM trees increase root C release as an adaptive response to dry soil to maintain hydraulic conductivity and/or nutrient availability. These systematic differences in key biogeochemical processes support hints on the key role of the mycorrhizal types in coupling C and N cycles in temperate forests. © The Author 2017. Published by Oxford

  1. Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

    DEFF Research Database (Denmark)

    Joner, E.J.; Jakobsen, I.

    1995-01-01

    precipitation leached through the soil, or indoor at constant moisture) with or without 9% (w/w) chopped wheat straw plus mineral N. Then the soils were partially sterilized and placed in two-compartment pots where mycorrhizal or non-mycorrhizal cucumber plants were grown in one root compartment (RC), and soils...... have influenced alkaline phosphatase excreted by other microorganisms, probably through competition for nutrients. Phosphatase activity was not correlated with the concentration of labile organic P in soil extracts....

  2. Bioactive and chemical properties of edible mycorrhizal mushrooms from Northeast Portugal

    OpenAIRE

    REIS, F. S.; Sandrina A. Heleno; Barros, Lillian; Sousa, Maria João; Martins, Anabela; Santos-Buelga, Celestino; Isabel C. F. R. Ferreira

    2011-01-01

    Mushrooms are widely appreciated all over the world for their nutritional properties1 and pharmacological value as sources of important bioactive compounds.2,3 Mycorrhizal macrofungi associate with plant roots constituting a symbiotic relationship, beneficial for both plant and fungus. In the present work five edible mycorrhizal species (Amanita caesarea, Cortinarius anomalus, Cortinarius violaceus, Lactarius volemus and Suillus luteus) from Northeast Portugal were studied for their bioac...

  3. Growth and nutrition of eucalyptus clones seedlings inoculated with mycorrhizal fungi

    OpenAIRE

    Francisco de Sousa Lima; Carla da Silva Sousa

    2014-01-01

    Eucalyptus is one of the most planted forest species, in Brazil, due to its rapid growth and high economic yield. Arbuscular mycorrhizal fungi improve the seedlings nutritional and phytosanitary status, besides increasing their resistance to biotic and abiotic stress. This study aimed to evaluate the effect of inoculation with arbuscular mycorrhizal fungi species on the growth and nutrition of different eucalyptus clones seedlings. The experiment was conducted under greenhouse conditions, in ...

  4. Arbuscular Mycorrhizal Fungi Promote the Growth of Ceratocarpus arenarius (Chenopodiaceae) with No Enhancement of Phosphorus Nutrition

    OpenAIRE

    Zhang, Tao; Shi, Ning; Bai, Dengsha; Chen, Yinglong; Feng, Gu

    2012-01-01

    The mycorrhizal status of plants in the Chenopodiaceae is not well studied with a few controversial reports. This study examined arbuscular mycorrhizal (AM) colonization and growth response of Ceratocarpus arenarius in the field and a greenhouse inoculation trial. The colonization rate of AM fungi in C. arenarius in in-growth field cores was low (around 15%). Vesicles and intraradical hyphae were present during all growth stages, but no arbuscules were observed. Sequencing analysis of the lar...

  5. Mycorrhizal specificity does not limit the distribution of an endangered orchid species.

    Science.gov (United States)

    Waud, Michael; Brys, Rein; Van Landuyt, Wouter; Lievens, Bart; Jacquemyn, Hans

    2017-03-01

    What factors determine the distribution of a species is a central question in ecology and conservation biology. In general, the distribution of plant species is assumed to be controlled by dispersal or environmentally controlled recruitment. For plant species which are critically dependent on mycorrhizal symbionts for germination and seedling establishment, specificity in mycorrhizal associations and availability of suitable mycorrhizal fungi can be expected to have a major impact on successful colonization and establishment and thus ultimately on a species distribution. We combined seed germination experiments with soil analyses and fungal assessments using 454 amplicon pyrosequencing to test the relative importance of dispersal limitation, mycorrhizal availability and local growth conditions on the distribution of the orchid species Liparis loeselii, which, despite being widely distributed, is rare and endangered in Europe. We compared local soil conditions, seed germination and mycorrhizal availability in the soil between locations in northern Belgium and France where L. loeselii occurs naturally and locations where conditions appear suitable, but where adults of the species are absent. Our results indicated that mycorrhizal communities associating with L. loeselii varied among sites and plant life cycle stages, but the observed variations did not affect seed germination, which occurred regardless of current L. loeselii presence and was significantly affected by soil moisture content. These results indicate that L. loeselii is a mycorrhizal generalist capable of opportunistically associating with a variety of fungal partners to induce seed germination. They also indicate that availability of fungal associates is not necessarily the determining factor driving the distribution of mycorrhizal plant species. © 2017 John Wiley & Sons Ltd.

  6. MycoDB, a global database of plant response to mycorrhizal fungi

    Science.gov (United States)

    Chaudhary, V. Bala; Rúa, Megan A.; Antoninka, Anita; Bever, James D.; Cannon, Jeffery; Craig, Ashley; Duchicela, Jessica; Frame, Alicia; Gardes, Monique; Gehring, Catherine; Ha, Michelle; Hart, Miranda; Hopkins, Jacob; Ji, Baoming; Johnson, Nancy Collins; Kaonongbua, Wittaya; Karst, Justine; Koide, Roger T.; Lamit, Louis J.; Meadow, James; Milligan, Brook G.; Moore, John C.; Pendergast, Thomas H., IV; Piculell, Bridget; Ramsby, Blake; Simard, Suzanne; Shrestha, Shubha; Umbanhowar, James; Viechtbauer, Wolfgang; Walters, Lawrence; Wilson, Gail W. T.; Zee, Peter C.; Hoeksema, Jason D.

    2016-05-01

    Plants form belowground associations with mycorrhizal fungi in one of the most common symbioses on Earth. However, few large-scale generalizations exist for the structure and function of mycorrhizal symbioses, as the nature of this relationship varies from mutualistic to parasitic and is largely context-dependent. We announce the public release of MycoDB, a database of 4,010 studies (from 438 unique publications) to aid in multi-factor meta-analyses elucidating the ecological and evolutionary context in which mycorrhizal fungi alter plant productivity. Over 10 years with nearly 80 collaborators, we compiled data on the response of plant biomass to mycorrhizal fungal inoculation, including meta-analysis metrics and 24 additional explanatory variables that describe the biotic and abiotic context of each study. We also include phylogenetic trees for all plants and fungi in the database. To our knowledge, MycoDB is the largest ecological meta-analysis database. We aim to share these data to highlight significant gaps in mycorrhizal research and encourage synthesis to explore the ecological and evolutionary generalities that govern mycorrhizal functioning in ecosystems.

  7. Model systems to unravel the molecular mechanisms of heavy metal tolerance in the ericoid mycorrhizal symbiosis.

    Science.gov (United States)

    Daghino, Stefania; Martino, Elena; Perotto, Silvia

    2016-05-01

    Ericoid mycorrhizal plants dominate in harsh environments where nutrient-poor, acidic soil conditions result in a higher availability of potentially toxic metals. Although metal-tolerant plant species and ecotypes are known in the Ericaceae, metal tolerance in these plants has been mainly attributed to their association with ericoid mycorrhizal fungi. The mechanisms underlying plant protection by the fungal symbiont are poorly understood, whereas some insights have been achieved regarding the molecular mechanisms of heavy metal tolerance in the fungal symbiont. This review will briefly introduce the general features of heavy metal tolerance in mycorrhizal fungi and will then focus on the use of "omics" approaches and heterologous expression in model organisms to reveal the molecular bases of fungal response to heavy metals. Functional complementation in Saccharomyces cerevisiae has allowed the identification of several ericoid mycorrhizal fungi genes (i.e., antioxidant enzymes, metal transporters, and DNA damage repair proteins) that may contribute to metal tolerance in a metal-tolerant ericoid Oidiodendron maius isolate. Although a powerful system, the use of the yeast complementation assay to study metal tolerance in mycorrhizal symbioses has limitations. Thus, O. maius has been developed as a model system to study heavy metal tolerance mechanisms in mycorrhizal fungi, thanks to its high metal tolerance, easy handling and in vitro mycorrhization, stable genetic transformation, genomics, transcriptomic and proteomic resources.

  8. Metagenomic Analyses of the Viruses Detected in Mycorrhizal Fungi and Their Host Orchid.

    Science.gov (United States)

    Shimura, Hanako; Masuta, Chikara; Koda, Yasunori

    2018-01-01

    In nature, mycorrhizal association with soilborne fungi is indispensable for orchid families. Fungal structures from compatible endo-mycorrhizal fungi in orchid cells are digested in cells to be supplied to orchids as nutrition. Because orchid seeds lack the reserves for germination, they keep receiving nutrition through mycorrhizal formation from seed germination until shoots develop (leaves) and become photoautotrophic. Seeds of all orchid species surely geminate with the help of their own fungal partners, and this specific partnership has been acquired for a long evolutional history between orchids and fungi.We have studied the interactions between orchids and mycorrhizal fungi and recently conducted transcriptome analyses (RNAseq) by a next-generation sequencing (NGS) approach. It is possible that orchid RNA isolated form naturally grown plants is contaminated with RNAs derived from mycorrhizal fungi in the orchid cells. To avoid such contamination, we here prepared aseptically germinated orchid plants (i.e., fungus-free plants) together with a pure-cultured fungal isolate and field-growing orchid samples. In the cDNA library prepared from orchid and fungal tissues, we found that partitivirus-like sequences were common in an orchid and its mycorrhizal fungus. These partitivirus-like sequences were closely related by a phylogenetic analysis, suggesting that transmission of an ancestor virus between the two organisms occurred through the specific relation of the orchid and its associated fungus.

  9. Enhancement of clover growth by inoculation of P-solubilizing fungi and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Souchie, Edson L; Azcón, Rosario; Barea, Jose M; Silva, Eliane M R; Saggin-Júnior, Orivaldo J

    2010-09-01

    This study evaluated the synergism between several P-solubilizing fungi isolates and arbuscular mycorrhizal fungi to improve clover ( Trifolium pratense) growth in the presence of Araxá apatite. Clover was sown directly in plastic pots with 300g of sterilized washed sand, vermiculite and sepiolite 1:1:1 (v:v:v) as substrate, and grown in a controlled environment chamber. The substrate was fertilized with 3 g L(-1) of Araxá apatite. A completely randomized design, in 8×2 factorial scheme (eight P-solubilizing fungi treatments with or without arbuscular mycorrhizal fungi)and four replicates were used. The P-solubilizing fungi treatments consisted of five Brazilian P-solubilizing fungi isolates (PSF 7, 9, 20, 21 and 22), two Spanish isolates ( Aspergillus niger and the yeast Yarowia lipolytica) and control (non-inoculated treatment). The greatest clover growth rate was recorded when Aspergillus niger and PSF 21 were co-inoculated with arbuscular mycorrhizal fungi. Aspergillus niger, PSF 7 and PSF 21 were the most effective isolates on increasing clover growth in the presence of arbuscular mycorrhizal fungi. Greater mycorrhizal colonization resulted in greater clover growth rate in most PSF treatments. PSF 7 was the best isolate to improve the establishment of mycorrhizal and rhizobia symbiosis.

  10. Role of arbuscular mycorrhizal symbiosis in root mineral uptake under CaCO3 stress.

    Science.gov (United States)

    Labidi, Sonia; Ben Jeddi, Fayçal; Tisserant, Benoit; Debiane, Djouher; Rezgui, Salah; Grandmougin-Ferjani, Anne; Lounès-Hadj Sahraoui, Anissa

    2012-07-01

    This study investigated the effects of increasing CaCO(3) concentrations (0, 5, 10, 20 mM) on arbuscular mycorrhizal (AM) symbiosis establishment as well as on chicory root growth and mineral nutrient uptake in a monoxenic system. Although CaCO(3) treatments significantly decreased root growth and altered the symbiosis-related development steps of the AM fungus Rhizophagus irregularis (germination, germination hypha elongation, root colonization rate, extraradical hyphal development, sporulation), the fungus was able to completely fulfill its life cycle. Even when root growth decreased more drastically in mycorrhizal roots than in non-mycorrhizal ones in the presence of high CaCO(3) levels, the AM symbiosis was found to be beneficial for root mineral uptake. Significant increases in P, N, Fe, Zn and Cu concentrations were recorded in the mycorrhizal roots. Whereas acid and alkaline phosphatase enzymatic activities remained constant in mycorrhizal roots, they were affected in non-mycorrhizal roots grown in the presence of CaCO(3) when compared with the control.

  11. Leucanthemum vulgare lam. germination, growth and mycorrhizal symbiosis under crude oil contamination.

    Science.gov (United States)

    Noori, Azam Sadat; Maivan, Hassan Zare; Alaie, Ebrahim

    2014-01-01

    Oil contamination of soil limits plants' access to water and nutrients. Leucanthemum vulgare colonized by mycorrhizae could provide an effective tool in remedying oil contamination. Seeds of L. vulgare were planted in pots containing soil mixed with petroleum at 0, 2.5, 5, 7.5, and 10% w/w and propagules of mycorrhizal fungi. Plants were grown under ambient conditions for 16 weeks. Seed germination data were collected weekly for three weeks. Mycorrhizal percentage, spore counts, length and weight of roots and shoots were determined after harvesting. Results showed significant differences in seed germination rates between oil-treated, mycorrhizal and non-mycorrhizal plants. The overall germination rate was greater at 7.5% w/w crude oil contamination (p = 0.05) in mycorrhizal and non-mycorrhizal pots with significant differences between their respective Root:Shoot ratios (both length and weight). Results of this research showed L. vulgare could be germinated and grown in crude oil contaminated soils and could be used to augment plant establishment as part of phytoremediation practices.

  12. Soil Mesofauna Response to Cover Crops and Mycorrhizal Inoculated Plantation on Limestone Quarry Revegetation

    Directory of Open Access Journals (Sweden)

    Retno Prayudyaningsih

    2016-06-01

    Full Text Available Cover crops establishment followed by mycorrhizal inoculated tree plantation accelerate limestone quaryy restoration. Soil mesofauna is a useful indicator for assessing biodiversity recovery, as they are sensitive to human disturbance and involved in ecological processes. In this research, soil mesofauna presence used to evaluate limestone quarry restoration by cover crops and mycorrhizal inoculated tree esatblisment. Soil mesofauna are measured using individual density, species diversity, richness and important value. The study was conducted in four types of areas on limestone postmining lands are open areas/natural conditions without planting, cover crop area, non mycorrhizalinoculated plant area and mycorrhizal-inoculated plant area. The result showed The higher individual density, diversity and species richness of soil mesofauna on cover crops and mycorrhizal inoculated plant area than other areas are indicators of limestone quarry restoration rate. Furthermore the presence of Formicidae family that dominated on cover crops and mycorrhizal inoculated plant area, and emergence of Acari group only on mycorrhizal inoculated area also an indicator of limestone quarry restoration.

  13. Carbon dynamics in mycorrhizal symbioses is linked to carbon costs and phosphorus benefits.

    Science.gov (United States)

    Olsson, Pål Axel; Rahm, Jannice; Aliasgharzad, Nasser

    2010-04-01

    The nutrient and carbon (C) allocation dynamics in mycorrhizal hyphal networks cause variation in costs and benefits for individual plants and fungi and influence the productivity, diversity and C cycling in ecosystems. We manipulated light and phosphorus (P) availability in a pot experiment with Trifolium subterraneum colonised by the arbuscular mycorrhizal (AM) fungus Glomus intraradices. Stable (13)C-labelling was used to trace assimilated CO(2) to the mycorrhizal fungus in roots and soil using compound-specific isotope ratio mass spectrometry. We used the neutral lipid fatty acid 16:1omega5 as a signature for AM fungal storage lipids. Both P and shading reduced the AM fungal lipid accumulation in the intraradical mycelium, while only P reduced the amount of lipids in the extraradical mycelium. Recently assimilated plant C was only allocated to the mycorrhizal fungus to a small extent when plant mycorrhizal benefit was reduced by P fertilization, while increasing the plant C cost by shading did not reduce the C flow to the fungus. These results are of importance for our conception of mycorrhizal dynamics during periods of shade in nature.

  14. Severe plant invasions can increase mycorrhizal fungal abundance and diversity

    DEFF Research Database (Denmark)

    Lekberg, Ylva; Gibbons, Sean; Rosendahl, Søren

    2013-01-01

    Invasions by non-native plants can alter ecosystem functions and reduce native plant diversity, but relatively little is known about their effect on belowground microbial communities. We show that invasions by knapweed (Centaurea stoebe) and leafy spurge (Euphorbia esula, hereafter spurge......)-but not cheatgrass (Bromus tectorum)-support a higher abundance and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) than multi-species native plant communities. The higher AMF richness associated with knapweed and spurge is unlikely due to a co-invasion by AMF, because a separate sampling showed...... that individual native forbs hosted a similar AMF abundance and richness as exotic forbs. Native grasses associated with fewer AMF taxa, which could explain the reduced AMF richness in native, grass-dominated communities. The three invasive plant species harbored distinct AMF communities, and analyses of co...

  15. Native arbuscular mycorrhizal fungi in the Yungas forests, Argentina.

    Science.gov (United States)

    Becerra, Alejandra G; Cabello, Marta N; Bartoloni, Norberto J

    2011-01-01

    The arbuscular mycorrhizal fungal (AMF) communities from the Yungas forests of Argentina were studied. The AMF species present in the rhizosphere of some dominant native plants (one tree: Alnus acuminata; three herbaceous species: Duchesnea indica, Oxalis conorrhiza, Trifolium aff. repens; and one shrub: Sambucus peruviana) from two sites (Quebrada del Portugués and Narváez Range) of the Yungas forests were isolated, identified and quantified during the four seasons of the year. Twenty-two AMF morphotaxa were found. Spore density of some AMF species at each site varied among seasons. The genera that most contributed to the biodiversity index were Acaulospora for Quebrada del Portugués and Glomus for Narváez Range. High diversity values were observed in the Yungas forests, particularly in the spring (rainy season). We concluded AMF differed in species composition and seasonal sporulation dynamics in the Yungas forests.

  16. Accumulation of apocarotenoids in mycorrhizal roots of leek (Allium porrum).

    Science.gov (United States)

    Schliemann, Willibald; Kolbe, Barbara; Schmidt, Jürgen; Nimtz, Manfred; Wray, Victor

    2008-05-01

    Colonization of the roots of leek (Allium porrum L.) by the arbuscular mycorrhizal fungus Glomus intraradices induced the formation of apocarotenoids, whose accumulation has been studied over a period of 25 weeks. Whereas the increase in the levels of the dominating cyclohexenone derivatives resembles the enhancement of root length colonization, the content of mycorradicin derivatives remains relatively low throughout. Structural analysis of the cyclohexenone derivatives by mass spectrometry and NMR spectroscopy showed that they are mono- and diglycosides of 13-hydroxyblumenol C and blumenol C acylated with 3-hydroxy-3-methyl-glutaric and/or malonic acid. Along with the isolation of three known compounds five others are shown to be hitherto unknown members of the fast-growing family of mycorrhiza-induced cyclohexenone conjugates.

  17. Strigolactones, signals for parasitic plants and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    García-Garrido, J M; Lendzemo, V; Castellanos-Morales, V; Steinkellner, S; Vierheilig, Horst

    2009-09-01

    Although strigolactones play a critical role as rhizospheric signaling molecules for the establishment of arbuscular mycorrhizal (AM) symbiosis and for seed germination of parasitic weeds, scarce data are available about interactions between AM fungi and strigolactones. In the present work, we present background data on strigolactones from studies on their seed germination activity on the parasitic weeds Orobanche and Striga, the importance of nitrogen and phosphorus for this seed germination activity, and what this could mean for AM fungi. We also present results on the susceptibility of plants to AM fungi and the possible involvement of strigolactones in this AM susceptibility and discuss the role of strigolactones for the formation and the regulation of the AM symbiosis as well as the possible implication of these compounds as plant signals in other soil-borne plant-microbe interactions.

  18. Impact of arbuscular mycorrhizal fungi on uranium accumulation by plants

    Energy Technology Data Exchange (ETDEWEB)

    Dupre de Boulois, H. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Joner, E.J. [Bioforsk Soil and Environment, Fredrik A. Dahls vei 20, N-1432 As (Norway); Leyval, C. [LIMOS, Nancy University, CNRS, Faculte des Sciences, BP239, 54506 Vandoeuvre-les-Nancy, Cedex (France); Jakobsen, I. [Biosystems Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Chen, B.D. [Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Roos, P. [Radiation Research Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Thiry, Y.; Rufyikiri, G. [CEN-SCK, Radiation Protection Research Department, 200 Boeretang, 2400 Mol (Belgium); Delvaux, B. [Universite catholique de Louvain, Unite des Sciences du Sol Croix du Sud 2/10, 1348 Louvain-la-Neuve (Belgium); Declerck, S. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)], E-mail: declerck@mbla.ucl.ac.be

    2008-05-15

    Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies.

  19. Diet of Arbuscular Mycorrhizal Fungi: Bread and Butter?

    Science.gov (United States)

    Rich, Mélanie K; Nouri, Eva; Courty, Pierre-Emmanuel; Reinhardt, Didier

    2017-08-01

    Most plants entertain mutualistic interactions known as arbuscular mycorrhiza (AM) with soil fungi (Glomeromycota) which provide them with mineral nutrients in exchange for reduced carbon from the plant. Mycorrhizal roots represent strong carbon sinks in which hexoses are transferred from the plant host to the fungus. However, most of the carbon in AM fungi is stored in the form of lipids. The absence of the type I fatty acid synthase (FAS-I) complex from the AM fungal model species Rhizophagus irregularis suggests that lipids may also have a role in nutrition of the fungal partner. This hypothesis is supported by the concerted induction of host genes involved in lipid metabolism. We explore the possible roles of lipids in the light of recent literature on AM symbiosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Nutrient Exchange and Regulation in Arbuscular Mycorrhizal Symbiosis.

    Science.gov (United States)

    Wang, Wanxiao; Shi, Jincai; Xie, Qiujin; Jiang, Yina; Yu, Nan; Wang, Ertao

    2017-09-12

    Most land plants form symbiotic associations with arbuscular mycorrhizal (AM) fungi. These are the most common and widespread terrestrial plant symbioses, which have a global impact on plant mineral nutrition. The establishment of AM symbiosis involves recognition of the two partners and bidirectional transport of different mineral and carbon nutrients through the symbiotic interfaces within the host root cells. Intriguingly, recent discoveries have highlighted that lipids are transferred from the plant host to AM fungus as a major carbon source. In this review, we discuss the transporter-mediated transfer of carbon, nitrogen, phosphate, potassium and sulfate, and present hypotheses pertaining to the potential regulatory mechanisms of nutrient exchange in AM symbiosis. Current challenges and future perspectives on AM symbiosis research are also discussed. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  1. Maintenance and preservation of ectomycorrhizal and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Lalaymia, Ismahen; Cranenbrouck, Sylvie; Declerck, Stéphane

    2014-07-01

    Short- to long-term preservation of mycorrhizal fungi is essential for their in-depth study and, in the case of culture collections, for safeguarding their biodiversity. Many different maintenance/preservation methods have been developed in the last decades, from soil- and substrate-based maintenance to preservation methods that reduce (e.g., storage under water) or arrest (e.g., cryopreservation) growth and metabolism; all have advantages and disadvantages. In this review, the principal methods developed so far for ectomycorrhizal and arbuscular mycorrhizal fungi are reported and described given their distinct biology/ecology/evolutionary history. Factors that are the most important for their storage are presented and a protocol proposed which is applicable, although not generalizable, for the long-term preservation at ultra-low temperature of a large panel of these organisms. For ECM fungi, isolates should be grown on membranes or directly in cryovials until the late stationary growth phase. The recommended cryopreservation conditions are: a cryoprotectant of 10% glycerol, applied 1-2 h prior to cryopreservation, a slow cooling rate (1 °C min(-1)) until storage below -130 °C, and fast thawing by direct plunging in a water bath at 35-37 °C. For AMF, propagules (i.e., spores/colonized root pieces) isolated from cultures in the late or stationary phase of growth should be used and incorporated in a carrier (i.e., soil or alginate beads), preferably dried, before cryopreservation. For in vitro-cultured isolates, 0.5 M trehalose should be used as cryoprotectant, while isolates produced in vivo can be preserved in dried soil without cryoprotectant. A fast cryopreservation cooling rate should be used (direct immersion in liquid nitrogen or freezing at temperatures below -130 °C), as well as fast thawing by direct immersion in a water bath at 35 °C.

  2. Enhanced production of steviol glycosides in mycorrhizal plants: a concerted effect of arbuscular mycorrhizal symbiosis on transcription of biosynthetic genes.

    Science.gov (United States)

    Mandal, Shantanu; Upadhyay, Shivangi; Singh, Ved Pal; Kapoor, Rupam

    2015-04-01

    Stevia rebaudiana (Bertoni) produces steviol glycosides (SGs)--stevioside (stev) and rebaudioside-A (reb-A) that are valued as low calorie sweeteners. Inoculation with arbuscular mycorrhizal fungi (AMF) augments SGs production, though the effect of this interaction on SGs biosynthesis has not been studied at molecular level. In this study transcription profiles of eleven key genes grouped under three stages of the SGs biosynthesis pathway were compared. The transcript analysis showed upregulation of genes encoding 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway enzymes viz.,1-deoxy-D-xylulose 5-phospate synthase (DXS), 1-deoxy-D-xylulose 5-phospate reductoisomerase (DXR) and 2-C-methyl-D-erytrithol 2,4-cyclodiphosphate synthase (MDS) in mycorrhizal (M) plants. Zn and Mn are imperative for the expression of MDS and their enhanced uptake in M plants could be responsible for the increased transcription of MDS. Furthermore, in the second stage of SGs biosynthesis pathway, mycorrhization enhanced the transcription of copalyl diphosphate synthase (CPPS) and kaurenoic acid hydroxylase (KAH). Their expression is decisive for SGs biosynthesis as CPPS regulates flow of metabolites towards synthesis of kaurenoid precursors and KAH directs these towards steviol synthesis instead of gibberellins. In the third stage glucosylation of steviol to reb-A by four specific uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs) occurs. While higher transcription of all the three characterized UGTs in M plants explains augmented production of SGs; higher transcript levels of UGT76G1, specifically improved reb-A to stev ratio implying increased sweetness. The work signifies that AM symbiosis upregulates the transcription of all eleven SGs biosynthesis genes as a result of improved nutrition and enhanced sugar concentration due to increased photosynthesis in M plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  4. Effects of nursery preconditioning through mycorrhizal inoculation and drought in Arbutus unedo L. plants.

    Science.gov (United States)

    Navarro García, Alejandra; Del Pilar Bañón Árias, Sebastián; Morte, Asunción; Sánchez-Blanco, María Jesús

    2011-01-01

    The influence of a water deficit treatment and mycorrhizal inoculation with Pisolithus tinctorius (Pers.) Coker and Couch on the water relations, gas exchange, and plant growth in Arbutus unedo L. plants was studied in order to evaluate the hardening process during the nursery period. The ability to withstand the adverse conditions after transplantation was also studied. Mycorrhizal and non-mycorrhizal seedlings of A. unedo were pot-grown for 4 months in a greenhouse (nursery period), during which time two irrigation treatments, well watered (100% water holding capacity, leaching 20% of the applied water) and deficit irrigation (50% of the well watered), were applied. Subsequently, the plants were transplanted to the field and well irrigated (transplanting period), after which and until the end of the experiment they received no water (establishment period). At the end of the nursery period, both water deficit and mycorrhizae were seen to have altered the plant morphology. Mycorrhizal plants had lower leaf area and improved leaf color parameters, while the water deficit increased root dry weight and the root/shoot ratio. Mycorrhizal plants had higher leaf water potential values than non-inoculated plants. Mycorrhizae increased stomatal conductance and photosynthesis values, especially in stressed plants. Drought led to an osmotic adjustment and a decrease in the leaf water potential values at turgor loss point in the mycorrhizal plants. Cell wall rigidity, measured as increased bulk modulus of elasticity, was decreased by the mycorrhizae effect. After transplanting, no differences were found in the water relations or gas exchange values between treatments. During the establishment period, the plants that had been exposed to both drought and mycorrhizae showed a better water status (higher leaf water and turgor potential values) and higher gas exchange values. In conclusion, water deficit and mycorrhizal inoculation of A. unedo plants in nursery produced changes in

  5. A meta-analysis of arbuscular mycorrhizal effects on plants grown under salt stress.

    Science.gov (United States)

    Chandrasekaran, Murugesan; Boughattas, Sonia; Hu, Shuijin; Oh, Sang-Hyon; Sa, Tongmin

    2014-11-01

    Salt stress limits crop yield and sustainable agriculture in most arid and semiarid regions of the world. Arbuscular mycorrhizal fungi (AMF) are considered bio-ameliorators of soil salinity tolerance in plants. In evaluating AMF as significant predictors of mycorrhizal ecology, precise quantifiable changes in plant biomass and nutrient uptake under salt stress are crucial factors. Therefore, the objective of the present study was to analyze the magnitude of the effects of AMF inoculation on growth and nutrient uptake of plants under salt stress through meta-analyses. For this, data were compared in the context of mycorrhizal host plant species, plant family and functional group, herbaceous vs. woody plants, annual vs. perennial plants, and the level of salinity across 43 studies. Results indicate that, under saline conditions, AMF inoculation significantly increased total, shoot, and root biomass as well as phosphorous (P), nitrogen (N), and potassium (K) uptake. Activities of the antioxidant enzymes superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase also increased significantly in mycorrhizal compared to nonmycorrhizal plants growing under salt stress. In addition, sodium (Na) uptake decreased significantly in mycorrhizal plants, while changes in proline accumulation were not significant. Across most subsets of the data analysis, identities of AMF (Glomus fasciculatum) and host plants (Acacia nilotica, herbs, woody and perennial) were found to be essential in understanding plant responses to salinity stress. For the analyzed dataset, it is concluded that under salt stress, mycorrhizal plants have extensive root traits and mycorrhizal morphological traits which help the uptake of more P and K, together with the enhanced production of antioxidant enzymes resulting in salt stress alleviation and increased plant biomass.

  6. DETERMINACIÓN DE LA DEPENDENCIA MICORRIZAL DEL LULO Determination Of Mycorrhizal Dependency Of Lulo

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    OCTAVIO GONZÁLEZ

    Full Text Available Se realizó un experimento de invernadero para determinar la dependencia micorrizal del lulo (Solanum quitoense Lam. híbrido “La selva”. Se utilizó un diseño experimental completamente al azar, los tratamientos tuvieron un arreglo factorial 3x2 con tres repeticiones; estos consistieron en la combinación de tres niveles de fósforo (P en la solución del suelo (0,002, 0,02 y 0,2 mg L-1 con dos niveles de inoculación del hongo micorrizal Glomus aggregatum (inoculado y no inoculado. Se emplearon como variables respuesta el contenido de P foliar en función del tiempo, la masa seca aérea y de raíces, la colonización micorrizal, la dependencia micorrizal y la morfología del sistema de raíces al momento de la cosecha. Los resultados indican que esta especie puede ser clasificada como moderadamente dependiente de la asociación micorrizal. La dependencia micorrizal fue mayor a 0,002 mg L-1. Todas las plantas inoculadas con G. aggregatum exhibieron colonización micorrizal, mientras que ninguna de las plantas no inoculadas desarrollaron la asociación micorrizal. La inoculación modificó significativamente la longitud y área superficial del sistema de raíces en las plantas de lulo en los niveles 0,002 y 0,02 mg L-1.A greenhouse experiment was carried out to determine the mycorrhizal dependency of lulo (Solanum quitoense Lam.. An experimental design completely randomized was used, treatments were arranged in factorial combination 3x2, which consisted of the combination of three soil solution phosphorus (P concentration (0.002, 0.02 and 0.2 mg L-1 and two levels of inoculation with the mycorrhizal fungus Glomus aggregatum (inoculated and uninoculated. Foliar P content was monitored as a function of time. At harvest, shoot and root dry weight, shoot P content, mycorrhizal colonization, mycorrhizal dependency, and root morphology were determined. The results indicated that lulo can be classified as moderately dependent on the mycorrhizal

  7. Diversity and dynamics of mycorrhizal associations in tropical rain forests with different disturbance regimes in South Cameroon

    NARCIS (Netherlands)

    Onguene, N.A.

    2000-01-01

    The present study documents the occurrence of mycorrhizal associations in the rain forests of south Cameroon. All species investigated are mycorrhizal. Most timber species form arbuscular mycorrhiza, but some timber species, which usually occur in clumps, form ectomycorrhiza. Species

  8. The arbuscular mycorrhizal fungus Rhizophagus irregularis differentially regulates the copper response of two maize cultivars differing in copper tolerance.

    Science.gov (United States)

    Merlos, Miguel A; Zitka, Ondrej; Vojtech, Adam; Azcón-Aguilar, Concepción; Ferrol, Nuria

    2016-12-01

    Arbuscular mycorrhiza can increase plant tolerance to heavy metals. The effects of arbuscular mycorrhiza on plant metal tolerance vary depending on the fungal and plant species involved. Here, we report the effect of the arbuscular mycorrhizal fungus Rhizophagus irregularis on the physiological and biochemical responses to Cu of two maize genotypes differing in Cu tolerance, the Cu-sensitive cv. Orense and the Cu-tolerant cv. Oropesa. Development of the symbiosis confers an increased Cu tolerance to cv. Orense. Root and shoot Cu concentrations were lower in mycorrhizal than in non-mycorrhizal plants of both cultivars. Shoot lipid peroxidation increased with soil Cu content only in non-mycorrhizal plants of the Cu-sensitive cultivar. Root lipid peroxidation increased with soil Cu content, except in mycorrhizal plants grown at 250mg Cu kg-1soil. In shoots of mycorrhizal plants of both cultivars, superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities were not affected by soil Cu content. In Cu-supplemented soils, total phytochelatin content increased in shoots of mycorrhizal cv. Orense but decreased in cv. Oropesa. Overall, these data suggest that the increased Cu tolerance of mycorrhizal plants of cv. Orense could be due to an increased induction of shoot phytochelatin biosynthesis by the symbiosis in this cultivar. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Plant-fungus competition for nitrogen erases mycorrhizal growth benefits of Andropogon gerardii under limited nitrogen supply

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Janoušková, Martina; Hujslová, M.; Slavíková, R.; Gryndlerová, H.; Jansa, J.

    2016-01-01

    Roč. 6, č. 13 (2016), s. 4332-4346 ISSN 2045-7758 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * nutrient uptake response * mycorrhizal benefits and costs Subject RIV: EF - Botanics Impact factor: 2.440, year: 2016

  10. Aspen-associated mycorrhizal fungal production and respiration as a function of changing CO2, O3 and climatic variables

    Science.gov (United States)

    Carrie J. Andrew; Linda T.A. van Diepen; R. Michael Miller; Erik A. Lilleskov

    2014-01-01

    The relationships of mycorrhizal fungal respiration and productivity to climate and atmospheric chemistry remain under characterized. We quantified mycorrhizal sporocarp and hyphal respiration, as well as growing season net hyphal production, under ambient and elevated carbon dioxide (CO2) and ozone (O3) in relation to...

  11. Plant Protection Research Institute

    Directory of Open Access Journals (Sweden)

    N. Allsopp

    1993-12-01

    Full Text Available A survey of the mycorrhizal status of plants growing in the Cape Floristic Region of South Africa was undertaken to assess the range of mycorrhizal types and their dominance in species characteristic of this region. Records were obtained by ex­amining the root systems of plants growing in three Cape lowland vegetation types, viz. West Coast Strandveld, West Coast Renosterveld and Sand Plain Lowland Fynbos for mycorrhizas, as well as by collating literature records of mycorrhizas on plants growing in the region. The mycorrhizal status of 332 species is listed, of which 251 species are new records. Members of all the important families in this region have been examined. Mycorrhizal status appears to be associated mainly with taxonomic position of the species. Extrapolating from these results, we conclude that 62% of the flora of the Cape Floristic Region form vesicular-arbuscular mycorrhizas, 23% have no mycorrhizas, 8% are ericoid mycorrhizal, 2% form orchid mycorrhizas, whereas the mycorrhizal status of 4% of the flora is unknown. There were no indigenous ectomycor- rhizal species. The proportion of non-mycorrhizal species is high compared to other ecosystems. In particular, the lack of mycorrhizas in several important perennial families in the Cape Floristic Region is unusual. The diversity of nutrient acquir­ing adaptations, including the range of mycorrhizas and cluster roots in some non-mycorrhizal families, may promote co­existence of plants in this species-rich region.

  12. Environmental and genetic effects on the formation of ectomycorrhizal and arbuscular mycorrhizal associations in cottonwoods.

    Science.gov (United States)

    Gehring, Catherine A; Mueller, Rebecca C; Whitham, Thomas G

    2006-08-01

    Although both environment and genetics have been shown to affect the mycorrhizal colonization of host plants, the impacts of these factors on hosts that can be dually colonized by both ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi are less understood. We examined the influence of environment and host crosstype on the EM and AM colonization of cottonwoods (Populus angustifolia and natural hybrids) by comparing levels of colonization of trees growing in common gardens that differed in elevation and soil type. We also conducted a supplemental watering experiment to determine the influence of soil moisture on AM and EM colonization. Three patterns emerged. First, garden location had a significant impact on mycorrhizal colonization, such that EM colonization was 30% higher and AM colonization was 85% lower in the higher elevation garden than the lower elevation garden. Second, crosstype affected total (EM + AM) colonization, but did not affect EM or AM colonization. Similarly, a significant garden x crosstype interaction was found for total colonization, but not for EM or AM colonization. Third, experimental watering resulted in 33% higher EM colonization and 45% lower AM colonization, demonstrating that soil moisture was a major driver of the mycorrhizal differences observed between the gardens. We conclude that environment, particularly soil moisture, has a larger influence on colonization by AM versus EM fungi than host genetics, and suggest that environmental stress may be a major determinant of mycorrhizal colonization in dually colonized host plants.

  13. Ecological specialization in mycorrhizal symbiosis leads to rarity in an endangered orchid.

    Science.gov (United States)

    Swarts, Nigel D; Sinclair, Elizabeth A; Francis, Anthony; Dixon, Kingsley W

    2010-08-01

    Terrestrial orchid germination, growth and development are closely linked to the establishment and maintenance of a relationship with a mycorrhizal fungus. Mycorrhizal dependency and specificity varies considerably between orchid taxa but the degree to which this underpins rarity in orchids is unknown. In the context of examining orchid rarity, large scale in vitro and in situ germination trials complemented by DNA sequencing were used to investigate ecological specialization in the mycorrhizal interaction of the rare terrestrial orchid Caladenia huegelii. Common and widespread sympatric orchid congeners were used for comparative purposes. Germination trials revealed an absolute requirement for mycorrhisation with compatibility barriers to germination limiting C. huegelii to a highly specific and range limited, efficacious mycorrhizal fungus. DNA sequencing confirmed fidelity between orchid and fungus across the distribution range of C. huegelii and at key life history stages within its life cycle. It was also revealed that common congeners could swap or share fungal partners including the fungus associated with the rare orchid but not vice versa. Data from this study provides evidence for orchid rarity as a cause and consequence of high mycorrhizal specialization. This interaction must be taken into account in efforts to mitigate the significant extinction risk for this species from anthropogenically induced habitat change and illustrates the importance of understanding fungal specificity in orchid ecology and conservation.

  14. Total fatty acid composition in the characterization and identification of orchid mycorrhizal fungi Epulorhiza spp.

    Directory of Open Access Journals (Sweden)

    Marlon Corrêa Pereira

    2011-08-01

    Full Text Available Rhizoctonia-like fungi are the main mycorrhizal fungi in orchid roots. Morphological characterization and analysis of conserved sequences of genomic DNA are frequently employed in the identification and study of fungi diversity. However, phytopathogenic Rhizoctonia-like fungi have been reliably and accurately characterized and identified through the examination of the fatty acid composition. To evaluate the efficacy of fatty acid composition in characterizing and identifying Rhizoctonia-like mycorrhizal fungi in orchids, three Epulorhiza spp. mycorrhizal fungi from Epidendrum secundum, two unidentified fungi isolated from Epidendrum denticulatum, and a phytopathogenic fungus, Ceratorhiza sp. AGC, were grouped based on the profile of their fatty acids, which was assessed by the Euclidian and Mahalanobis distances and the UPGMA method. Dendrograms distinguished the phytopathogenical isolate of Ceratorhiza sp. AGC from the mycorrhizal fungi studied. The symbionts of E. secundum were grouped into two clades, one containing Epulorhiza sp.1 isolates and the other the Epulorhiza sp.2 isolate. The similarity between the symbionts of E. denticulatum and Epulorhiza spp. fungi suggests that symbionts found in E. denticulatum may be identified as Epulorhiza. These results were corroborated by the analysis of the rDNA ITS region. The dendrogram constructed based on the Mahalanobis distance differentiated the clades most clearly. Fatty acid composition analysis proved to be a useful tool for characterizing and identifying Rhizoctonia-like mycorrhizal fungi.

  15. Nutraceutical value and safety of tomato fruits produced by mycorrhizal plants.

    Science.gov (United States)

    Giovannetti, M; Avio, L; Barale, R; Ceccarelli, N; Cristofani, R; Iezzi, A; Mignolli, F; Picciarelli, P; Pinto, B; Reali, D; Sbrana, C; Scarpato, R

    2012-01-01

    Tomato fruit has assumed the status of 'functional food' due to the association between its consumption and a reduced likelihood of certain types of cancers and CVD. The nutraceutical value of tomatoes can be affected by the cultivation conditions, e.g. the phytochemical content of the fruits may increase with the establishment of beneficial mycorrhizal symbioses in the plants. A multidisciplinary study was carried out to gain knowledge on the antioxidant, oestrogenic/anti-oestrogenic and genotoxic activity of tomato fruits produced by mycorrhizal plants. The present results showed that the symbiosis positively affected the growth and mineral nutrient content of tomato plants and enhanced the nutritional and nutraceutical value of tomato fruits through modifications of plant secondary metabolism, which led to increased levels of lycopene in fruits obtained from mycorrhizal plants, compared with controls. Moreover, such changes did not result in the production of mutagenic compounds, since tomato extracts induced no in vitro genotoxic effects. Fruit extracts, both hydrophilic and the lipophilic fractions, originating from mycorrhizal plants strongly inhibited 17-β-oestradiol-human oestrogen receptor binding, showing significantly higher anti-oestrogenic power compared with controls. The present study shows that beneficial plant symbionts, such as mycorrhizal fungi, can lead to the production of safe and high-quality food, which is an important societal issue strongly demanded by both consumers and producers.

  16. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening.

    Science.gov (United States)

    Chialva, Matteo; Zouari, Inès; Salvioli, Alessandra; Novero, Mara; Vrebalov, Julia; Giovannoni, James J; Bonfante, Paola

    2016-07-01

    Systemic responses to an arbuscular mycorrhizal fungus reveal opposite phenological patterns in two tomato ripening mutants depending whether ethylene or light reception is involved. The availability of tomato ripening mutants has revealed many aspects of the genetics behind fleshy fruit ripening, plant hormones and light signal reception. Since previous analyses revealed that arbuscular mycorrhizal symbiosis influences tomato berry ripening, we wanted to test the hypothesis that an interplay might occur between root symbiosis and fruit ripening. With this aim, we screened seven tomato mutants affected in the ripening process for their responsiveness to the arbuscular mycorrhizal fungus Funneliformis mosseae. Following their phenological responses we selected two mutants for a deeper analysis: Green ripe (Gr), deficient in fruit ethylene perception and high-pigment-1 (hp-1), displaying enhanced light signal perception throughout the plant. We investigated the putative interactions between ripening processes, mycorrhizal establishment and systemic effects using biochemical and gene expression tools. Our experiments showed that both mutants, notwithstanding a normal mycorrhizal phenotype at root level, exhibit altered arbuscule functionality. Furthermore, in contrast to wild type, mycorrhization did not lead to a higher phosphate concentration in berries of both mutants. These results suggest that the mutations considered interfere with arbuscular mycorrhiza inducing systemic changes in plant phenology and fruits metabolism. We hypothesize a cross talk mechanism between AM and ripening processes that involves genes related to ethylene and light signaling.

  17. Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize

    Directory of Open Access Journals (Sweden)

    Gu Feng

    2017-04-01

    Full Text Available Phytate is the most abundant form of soil organic phosphorus (P. Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize (Zea mays L. cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi Funneliformis mosseae or Claroideoglomus etunicatum, were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg-1 soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1 phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2 increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3 lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.

  18. Occurrence of arbuscular mycorrhizal fungi on King George Island, South Shetland Islands, Antarctica

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    MARISÂNGELA V. BARBOSA

    2017-08-01

    Full Text Available ABSTRACT Arbuscular mycorrhizal fungi make up an important ecological niche in ecosystems, and knowledge of their diversity in extreme environments is still incipient. The objective of this work was to evaluate the density and diversity of arbuscular mycorrhizal fungi in the soil of King George Island in the South Shetland Islands archipelago, Antarctica. For that, soil and roots of Deschampsia antarctica were collected at the brazilian research station in Antarctica. The spore density, species diversity and mycorrhizal colonization in the roots were evaluated. There was a low density of spores (27.4 ± 17.7 and root mycorrhizal colonization (6 ± 5.1%, which did not present statistical difference. Four species of arbuscular mycorrhizal fungi were identified, distributed in two genera: three species of the genus Glomus (Glomus sp1, Glomus sp2 and Glomus sp3 and one of the genus Acaulospora, which was identified at species level (Acaulospora mellea. Greater soil diversity was verified with pH 5.9 and phosphorus concentration of 111 mg dm-3, occurring two species of genus Glomus and A. mellea. Based on literature data, this may be the first record of this species of Acaulospora mellea in Antarctic soils, colonizing D. antarctica plants.

  19. EFFECT OF DIESEL AND BIODIESEL ON THE GROWTH OF Brachiaria decumbens INOCULATED WITH ARBUSCULAR MYCORRHIZAL FUNGI

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    Dora Trejo

    2013-12-01

    Full Text Available Arbuscular mycorrhizal fungi have been found to be associated with plants useful in soil phytoremediation. The aim of this study was to compare the effects of diesel and biodiesel in soil and sand on the growth of Brachiaria decumbens inoculated with mycorrhizae. Two experiments were carried out: one experiment in soil and another in sand. A two-level- factorial design with three factors was used (one on sterile and another on non-sterile soil, with and without mycorrhizae; and one with diesel and another with biodiesel. In sand, a two-factor design with two levels was used (with and without mycorrhizae and with diesel and biodiesel, both with three replications. NOVADIESEL, biodiesel and PEMEX diesel were use as contaminants, both at 7%. The fresh and dry weight of the plants and percentage of mycorrhizal colonization, were assessed 30 days after planting. In soil, biodiesel was more toxic and reduced the fresh and dry weights of plants, especially in non-sterile soil. Biodiesel yielded greater mycorrhizal colonization values that doubled those of the control. In sand, diesel was found to reduce three times the fresh and dry weights of plants, compared to the biodiesel. In sand diesel presented high values of mycorrhizal colonization in comparison with biodiesel.  Plants inoculated with mycorrhizal fungi exhibited better development than non-inoculated plants, even in the presence of contaminants.

  20. Effects of tree species, water and nitrogen on mycorrhizal C flux

    Science.gov (United States)

    Menyailo, O.; Matvienko, A.

    2012-12-01

    Mycorrhiza plays an important role in global carbon cycle, especially, in forest soils, yet the effect of tree species on the amount and timing of C transfer through roots to myccorhiza is largely unknown. We studied the C transport to mycorrhiza under 6 most commonly dominant in boreal forests tree species using the mesh collars installed at the Siberian afforestation experiment. The CO2 flux from mycorrhizal and non-mycorrhizal mesh collars indicated the mycorrhizal C flux. Tree species strongly differed in C flux to mycorrhiza: more C was transferred by deciduous species than by conifers. The mycorrhizal CO2 flux was not linked to soil temperature but rather to trees phenology and to photosynthetic activity. All tree species transfered more carbon to mycorrhiza during the second half of summer and in September, this is because all the carbon photosynthesized earlier is used for building the tree biomass. Seasonal variation in C transfer to mycorrhiza was much larger than hourly variation (within a day). Nitrogen application (50 kg/ha) increased mycorrhizal C flux only under Scots pine, but not under larch, thus the effect of N application is tree species dependent. We found under most tree species that more C was transferred by trees to mycorrhiza in root-free collars, where the soil moisture was higher than in collars with roots. This suggests that trees preferentially support those parts of mycorrhiza, which can gain extra-resources.

  1. An integrated functional approach to dissect systemic responses in maize to arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Gerlach, Nina; Schmitz, Jessica; Polatajko, Aleksandra; Schlüter, Urte; Fahnenstich, Holger; Witt, Sandra; Fernie, Alisdair R; Uroic, Kalle; Scholz, Uwe; Sonnewald, Uwe; Bucher, Marcel

    2015-08-01

    Most terrestrial plants benefit from the symbiosis with arbuscular mycorrhizal fungi (AMF) mainly under nutrient-limited conditions. Here the crop plant Zea mays was grown with and without AMF in a bi-compartmented system separating plant and phosphate (Pi) source by a hyphae-permeable membrane. Thus, Pi was preferentially taken up via the mycorrhizal Pi uptake pathway while other nutrients were ubiquitously available. To study systemic effects of mycorrhizal Pi uptake on leaf status, leaves of these plants that display an increased biomass in the presence of AMF were subjected to simultaneous ionomic, transcriptomic and metabolomic analyses. We observed robust changes of the leaf elemental composition, that is, increase of P, S and Zn and decrease of Mn, Co and Li concentration in mycorrhizal plants. Although changes in anthocyanin and lipid metabolism point to an improved P status, a global increase in C versus N metabolism highlights the redistribution of metabolic pools including carbohydrates and amino acids. Strikingly, an induction of systemic defence gene expression and concomitant accumulation of secondary metabolites such as the terpenoids alpha- and beta-amyrin suggest priming of mycorrhizal maize leaves as a mycorrhiza-specific response. This work emphasizes the importance of AM symbiosis for the physiological status of plant leaves and could lead to strategies for optimized breeding of crop species with high growth potential. © 2015 John Wiley & Sons Ltd.

  2. [Arbuscular mycorrhizal symbiosis influences the biological effects of nano-ZnO on maize].

    Science.gov (United States)

    Wang, Wei-Zhong; Wang, Fa-Yuan; Li, Shuai; Liu, Xue-Qin

    2014-08-01

    Engineered nanoparticles (ENPs) can be taken up and accumulated in plants, then enter human bodies via food chain, and thus cause potential health risk. Arbuscular mycorrhizal fungi form mutualistic symbioses with the majority of higher plants in terrestrial ecosystems, and potentially influence the biological effects of ENPs. The present greenhouse pot culture experiment studied the effects of inoculation with or without arbuscular mycorrhizal fungus Acaulospora mellea on growth and nutritional status of maize under different nano-ZnO levels (0, 500, 1 000, 2000 and 3 000 mg x kg(-1)) artificially added into soil. Results showed that with the increasing nano-ZnO levels in soil, mycorrhizal colonization rate and biomass of maize plants showed a decreasing trend, total root length, total surface area and total volume reduced, while Zn concentration and uptake in plants gradually increased, and P, N, K, Fe, and Cu uptake in shoots all decreased. Compared with the controls, arbuscular mycorrhizal inoculation improved the growth and P, N and K nutrition of maize, enhanced total root length, total surface area and total volume, and increased Zn allocation to roots when nano-ZnO was added. Our results firstly show that nano-ZnO in soil induces toxicity to arbuscular mycorrhizae, while arbuscular mycorrhizal inoculation can alleviate its toxicity and play a protective role in plants.

  3. POTENCIAL SIMBIOTICO Y EFECTIVIDAD DE HONGOS MICORRIZO ARBUSCULARES DE TRES SUELOS SOMETIDOS A DIFERENTES USOS MYCORRHIZAL SYMBIOTIC POTENTIAL AND EFFECTIVENESS OF THREE SOILS UNDER DIFFERENT USES

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Jaramillo Padilla

    2004-06-01

    consisting of a soil-quartz (1:1 ratio mixture. The substrate was inoculated with a crude inoculum of Glomus aggregatum, a mycorrhizal fungus of known effectiveness. Mycorrhizal effectiveness was evaluated by monitoring P pinnule content of the leucaena seedlings at regular intervals of time during the growth period of 49 days. At harvest, shoot dry mass, shoot P content, and mycorrhizal colonization were determined. Plant growth and P uptake were significantly higher in plants growing in the substrate inoculated with G. aggregatum than those plants grown in either non-inoculated substrate or substrate inoculated with aliquots of tested soils. Mycorrhizal colonization was very high in the G. aggregtaum inoculated-substrate and virtually absent in the other treatments. Results suggest that in the tested soils there were a low mycorrhizal effectiveness and/or low content of mycorrizal infective propagules, which was confirmed by the most-probable-number method and mycorrhizal spore counting.

  4. ARBUSCULAR MYCORRHIZAL FUNGI IN SUCCESSIONAL STAGES OF CAATINGA IN THE SEMI-ARID REGION OF BRAZIL

    Directory of Open Access Journals (Sweden)

    Carla da Silva Sousa

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813331Caatinga is an exclusively Brazilian biome with areas in accentuated process of desertification. Arbuscularmycorrhizal fungi (AMF act in plant succession by favoring the establishment of plant species typical ofsuccessional stages and by accelerating recovery leading to a climax stage. The objective of the present workwas to evaluate the occurrence and diversity of AMF in successional stages of caatinga in the semi-aridregion of Paraíba State. Experimental plots (30 x 60 m were delimitated in 2007 in areas corresponding todifferent caatinga successional stages: early caatinga succession (natural revegetation during the previous15 years; intermediate (natural revegetation for about 35 years; late (mature caatinga with more than50 years without major disturbances; and also in pasture areas fenced and protected to represent the initialphase of succession. Plots of all four stages were implemented with three replicates. Soil and root sampleswere collected in the experimental plots, from the 0-15 cm soil layer in the dry and in the rainy seasons.All areas presented low infectivity potential suggesting that the introduction of mycorrhizal seedlings mayaccelerate the process of revegetation of degraded soils in this region. Except for the areas of late stage, theglomalin reservoirs increased along with the advancement of the succession process. Areas in the late stageof succession presented greater richness of AMF species, indicating that the establishment of the vegetationalso exerts a significant effect in the fungal community. Glomus and Acaulospora species were predominantin both seasons, possibly because they are well adapted to semi-arid conditions

  5. Contrasting phosphate acquisition of mycorrhizal fungi with that of root hairs using the root hairless barley mutant

    DEFF Research Database (Denmark)

    Jakobsen, I.; Chen, B.D.; Munkvold, L.

    2005-01-01

    Comparisons between plant species or cultivars differing in root hair length have indicated a major impact of root hairs on the mycorrhizal dependency of plants with respect to phosphate (P) uptake. The current study aimed to investigate this relationship by comparing directly the mycorrhizal dep...... effectively in promoting plant growth than P provided by root hairs.......Comparisons between plant species or cultivars differing in root hair length have indicated a major impact of root hairs on the mycorrhizal dependency of plants with respect to phosphate (P) uptake. The current study aimed to investigate this relationship by comparing directly the mycorrhizal...... plants at low P levels was substantially lower than that of the non-mycorrhizal wild-type plants. However, P uptake of the mutant was much increased by mycorrhizas and with one fungus, the additional P uptake was effectively translated into increased plant growth. Roots of the mutant contained typical...

  6. RbohB, a Phaseolus vulgaris NADPH oxidase gene, enhances symbiosome number, bacteroid size, and nitrogen fixation in nodules and impairs mycorrhizal colonization.

    Science.gov (United States)

    Arthikala, Manoj-Kumar; Sánchez-López, Rosana; Nava, Noreide; Santana, Olivia; Cárdenas, Luis; Quinto, Carmen

    2014-05-01

    The reactive oxygen species (ROS) generated by respiratory burst oxidative homologs (Rbohs) are involved in numerous plant cell signaling processes, and have critical roles in the symbiosis between legumes and nitrogen-fixing bacteria. Previously, down-regulation of RbohB in Phaseolus vulgaris was shown to suppress ROS production and abolish Rhizobium infection thread (IT) progression, but also to enhance arbuscular mycorrhizal fungal (AMF) colonization. Thus, Rbohs function both as positive and negative regulators. Here, we assessed the effect of enhancing ROS concentrations, by overexpressing PvRbohB, on the P. vulgaris--rhizobia and P. vulgaris--AMF symbioses. We estimated superoxide concentrations in hairy roots overexpressing PvRbohB, determined the status of early and late events of both Rhizobium and AMF interactions in symbiont-inoculated roots, and analyzed the nodule ultrastructure of transgenic plants overexpressing PvRbohB. Overexpression of PvRbohB significantly enhanced ROS production, the formation of ITs, nodule biomass, and nitrogen-fixing activity, and increased the density of symbiosomes in nodules, and the density and size of bacteroides in symbiosomes. Furthermore, PvCAT, early nodulin, PvSS1, and PvGOGAT transcript abundances were elevated in these nodules. By contrast, mycorrhizal colonization was reduced in roots that overexpressed RbohB. Overexpression of PvRbohB augmented nodule efficiency by enhancing nitrogen fixation and delaying nodule senescence, but impaired AMF colonization. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  7. Increased Salinity Tolerance of Cowpea Plants by Dual Inoculation of an Arbuscular Mycorrhizal Fungus Glomus clarum and a Nitrogen-fixer Azospirillum brasilense.

    Science.gov (United States)

    Rabie, G H; Aboul-Nasr, M B; Al-Humiany, A

    2005-03-01

    Pot greenhouse experiments were carried out to attempt to increase the salinity tolerance of one of the most popular legume of the world; cowpea; by using dual inoculation of an Am fungus Glomus clarum and a nitrogen-fixer Azospirillum brasilense. The effect of these beneficial microbes, as single- or dual inoculation-treatments, was assessed in sterilized loamy sand soil at five NaCl levels (0.0~7.2 ds/m) in irrigating water. The results of this study revealed that percentage of mycorrhizal infection, plant height, dry weight, nodule number, protein content, nitrogenase and phosphatase activities, as well as nutrient elements N, P, K, Ca, Mg were significantly decreased by increasing salinity level in non-mycorrhized plants in absence of NFB. Plants inoculated with NFB showed higher nodule numbers, protein content, nitrogen concentration and nitrogenase activities than those of non-inoculated at all salinity levels. Mycorrhized plants exhibited better improvement in all measurements than that of non-mycorrhized ones at all salinity levels, especially, in the presence of NFB. The concentration of Na(+) was significantly accumulated in cowpea plants by rising salinity except in shoots of mycorrhizal plants which had K(+)/Na(+) ratios higher than other treatments. This study indicated that dual inoculation with Am fungi and N-fixer Azospirillum can support both needs for N and P, excess of NaCl and will be useful in terms of soil recovery in saline area.

  8. Plant tolerance to mercury in a contaminated soil is enhanced by the combined effects of humic matter addition and inoculation with arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Cozzolino, V; De Martino, A; Nebbioso, A; Di Meo, V; Salluzzo, A; Piccolo, A

    2016-06-01

    In a greenhouse pot experiment, lettuce plants (Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg(-1) of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops.

  9. Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient1[OPEN

    Science.gov (United States)

    Mullinix, George W.R.; Ward, Joy K.

    2016-01-01

    Rising atmospheric carbon dioxide concentration ([CO2]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO2] gradient (180–1,000 µL L−1). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO2] and arbuscular mycorrhizal fungi. To evaluate [CO2] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (MBio) and nonmycorrhizal (NMBio) plants (RBio = [MBio − NMBio]/NMBio). We then assessed linkages between RBio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, RBio increased with rising [CO2], shifting from negative to positive values at 700 µL L−1. [CO2] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in RBio in this species. For T. ceratophorum, RBio increased from 180 to 390 µL L−1 and further increases in [CO2] caused RBio to shift from positive to negative values. [CO2] and fungal effects on plant growth and carbon sink strength were correlated with shifts in RBio in this species. Overall, we show that rising [CO2] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO2], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO2]. The magnitude and mechanisms driving mycorrhizal-CO2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. PMID:27573369

  10. Biofertilizers and sustainable agriculture: exploring arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Igiehon, Nicholas O; Babalola, Olubukola O

    2017-06-01

    Worldwide agricultural food production has to double in 2050 so as to feed the global increasing population while reducing dependency on conventional chemical fertilizers plus pesticides. To accomplish this objective, there is the need to explore the several mutualistic interactions between plant roots and rhizosphere microbiome. Biofertilization is the process of boosting the abundance of microorganisms such as arbuscular mycorrhizal fungi (AMF) in the natural plant rhizosphere which depicts a beneficial alternative to chemical fertilization practices. Mineral nutrients uptake by AMF are plausible by means of transporters coded for by different genes and example include phosphate transporter. These fungi can be produced industrially using plant host and these, including the possibility of AMF contamination by other microorganism, are factors militating against large scale production of AMF. AMF isolates can be inoculated in the greenhouse or field, and it has been shown that AMF survival and colonization level were enhanced in soybeans grown on land that was previously cultivated with the same plant. Next generation sequencing (NGS) is now used to gain insight into how AMF interact with indigenous AMF and screen for beneficial microbial candidates. Besides application as biofertilizers, novel findings on AMF that could contribute to maintenance of agricultural development include AMF roles in controlling soil erosion, enhancing phytoremediation, and elimination of other organisms that may be harmful to crops through common mycelia network. The combination of these potentials when fully harnessed under agricultural scenario will help to sustain agriculture and boost food security globally.

  11. Dispersal of arbuscular mycorrhizal fungi and plants during succession

    Science.gov (United States)

    García de León, David; Moora, Mari; Öpik, Maarja; Jairus, Teele; Neuenkamp, Lena; Vasar, Martti; Bueno, C. Guillermo; Gerz, Maret; Davison, John; Zobel, Martin

    2016-11-01

    Arbuscular mycorrhizal (AM) fungi are important root symbionts that enhance plant nutrient uptake and tolerance to pathogens and drought. While the role of plant dispersal in shaping successional vegetation is well studied, there is very little information about the dispersal abilities of AM fungi. We conducted a trap-box experiment in a recently abandoned quarry at 10 different distances from the quarry edge (i.e. the potential propagule source) over eleven months to assess the short term, within-year, arrival of plant and AM fungal assemblages and hence their dispersal abilities. Using DNA based techniques we identified AM fungal taxa and analyzed their phylogenetic diversity. Plant diversity was determined by transporting trap soil to a greenhouse and identifying emerging seedlings. We recorded 30 AM fungal taxa. These contained a high proportion of ruderal AM fungi (30% of taxa, 79% of sequences) but the richness and abundance of AM fungi were not related to the distance from the presumed propagule source. The number of sequences of AM fungi decreased over time. Twenty seven plant species (30% of them ruderal) were recorded from the soil seed traps. Plant diversity decreased with distance from the propagule source and increased over time. Our data show that AM fungi with ruderal traits can be fast colonizers of early successional habitats.

  12. Elemental composition of arbuscular mycorrhizal fungi at high salinity.

    Science.gov (United States)

    Hammer, Edith C; Nasr, Hafedh; Pallon, Jan; Olsson, Pål Axel; Wallander, Håkan

    2011-02-01

    We investigated the elemental composition of spores and hyphae of arbuscular mycorrhizal fungi (AMF) collected from two saline sites at the desert border in Tunisia, and of Glomus intraradices grown in vitro with or without addition of NaCl to the medium, by proton-induced X-ray emission. We compared the elemental composition of the field AMF to those of the soil and the associated plants. The spores and hyphae from the saline soils showed strongly elevated levels of Ca, Cl, Mg, Fe, Si, and K compared to their growth environment. In contrast, the spores of both the field-derived AMF and the in vitro grown G. intraradices contained lower or not elevated Na levels compared to their growth environment. This resulted in higher K:Na and Ca:Na ratios in spores than in soil, but lower than in the associated plants for the field AMF. The K:Na and Ca:Na ratios of G. intraradices grown in monoxenic cultures were also in the same range as those of the field AMF and did not change even when those ratios in the growth medium were lowered several orders of magnitude by adding NaCl. These results indicate that AMF can selectively take up elements such as K and Ca, which act as osmotic equivalents while they avoid uptake of toxic Na. This could make them important in the alleviation of salinity stress in their plant hosts.

  13. Arbuscular mycorrhizal fungi: effects on plant terpenoid accumulation.

    Science.gov (United States)

    Welling, M T; Liu, L; Rose, T J; Waters, D L E; Benkendorff, K

    2016-07-01

    Arbuscular mycorrhizal fungi (AMF) are a diverse group of soil-dwelling fungi that form symbiotic associations with land plants. AMF-plant associations promote the accumulation of plant terpenoids beneficial to human health, although how AMF mediate terpenoid accumulation is not fully understood. A critical assessment and discussion of the literature relating to mechanisms by which AMF influence plant terpenoid accumulation, and whether this symbiosis can be harnessed in horticultural ecosystems was performed. Modification of plant morphology, phosphorus availability and gene transcription involved with terpenoid biosynthetic pathways were identified as key mechanisms associated with terpenoid accumulation in AMF-colonised plants. In order to exploit AMF-plant symbioses in horticultural ecosystems it is important to consider the specificity of the AMF-plant association, the predominant factor affecting terpenoid accumulation, as well as the end use application of the harvested plant material. Future research should focus on resolving the relationship between ecologically matched AMF genotypes and terpenoid accumulation in plants to establish if these associations are effective in promoting mechanisms favourable for plant terpenoid accumulation. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. Compatibility and incompatibility in hyphal anastomosis of arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Candido Barreto de Novais

    Full Text Available ABSTRACT: Arbuscular mycorrhizal fungi (AMF, which live in symbiosis with 80 % of plants, are not able to grow when separated from their hosts. Spore germination is not host-regulated and germling growth is shortly arrested in the absence of host roots. Germling survival chances may be increased by hyphal fusions (anastomoses, which allow access to nutrients flowing in the extraradical mycelium (ERM. Perfect anastomoses, occurring with high frequency among germlings and the ERM of the same isolate, show protoplasm continuity and disappearance of hyphal walls. A low frequency of perfect fusions has been detected among co-specific genetically different isolates, although fungal nuclei have been consistently detected in all perfect fusions, suggesting active nuclear migration. When plants of different taxa establish symbioses with the same AMF species, anastomoses between ERM spreading from single root systems establish a common mycelium, which is an essential element to plant nutrition and communication. The interaction among mycelia produced by different isolates may also lead to pre-fusion incompatibility which hinders anastomosis formation, or to incompatibility after fusion, which separates the hyphal compartments. Results reported here, obtained by analyses of hyphal compatibility/incompatibility in AMF, suggest that anastomosis formation and establishment of protoplasm flow, fundamental to the maintenance of mycelial physiological and genetic continuity, may affect the fitness of these ecologically important biotrophic fungi.

  15. Shoot- and root-borne cytokinin influences arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Cosme, Marco; Ramireddy, Eswarayya; Franken, Philipp; Schmülling, Thomas; Wurst, Susanne

    2016-10-01

    The arbuscular mycorrhizal (AM) symbiosis is functionally important for the nutrition and growth of most terrestrial plants. Nearly all phytohormones are employed by plants to regulate the symbiosis with AM fungi, but the regulatory role of cytokinin (CK) is not well understood. Here, we used transgenic tobacco (Nicotiana tabacum) with a root-specific or constitutive expression of CK-degrading CKX genes and the corresponding wild-type to investigate whether a lowered content of CK in roots or in both roots and shoots influences the interaction with the AM fungus Rhizophagus irregularis. Our data indicates that shoot CK has a positive impact on AM fungal development in roots and on the root transcript level of an AM-responsive phosphate transporter gene (NtPT4). A reduced CK content in roots caused shoot and root growth depression following AM colonization, while neither the uptake of phosphorus or nitrogen nor the root transcript levels of NtPT4 were significantly affected. This suggests that root CK may restrict the C availability from the roots to the fungus thus averting parasitism by AM fungi. Taken together, our study indicates that shoot- and root-borne CK have distinct roles in AM symbiosis. We propose a model illustrating how plants may employ CK to regulate nutrient exchange with the ubiquitous AM fungi.

  16. Plant Signaling and Metabolic Pathways Enabling Arbuscular Mycorrhizal Symbiosis.

    Science.gov (United States)

    MacLean, Allyson M; Bravo, Armando; Harrison, Maria J

    2017-10-01

    Plants have lived in close association with arbuscular mycorrhizal (AM) fungi for over 400 million years. Today, this endosymbiosis occurs broadly in the plant kingdom where it has a pronounced impact on plant mineral nutrition. The symbiosis develops deep within the root cortex with minimal alterations in the external appearance of the colonized root; however, the absence of macroscopic alterations belies the extensive signaling, cellular remodeling, and metabolic alterations that occur to enable accommodation of the fungal endosymbiont. Recent research has revealed the involvement of a novel N-acetyl glucosamine transporter and an alpha/beta-fold hydrolase receptor at the earliest stages of AM symbiosis. Calcium channels required for symbiosis signaling have been identified, and connections between the symbiosis signaling pathway and key transcriptional regulators that direct AM-specific gene expression have been established. Phylogenomics has revealed the existence of genes conserved for AM symbiosis, providing clues as to how plant cells fine-tune their biology to enable symbiosis, and an exciting coalescence of genome mining, lipid profiling, and tracer studies collectively has led to the conclusion that AM fungi are fatty acid auxotrophs and that plants provide their fungal endosymbionts with fatty acids. Here, we provide an overview of the molecular program for AM symbiosis and discuss these recent advances. © 2017 American Society of Plant Biologists. All rights reserved.

  17. Mycorrhizal colonisation of highbush blueberry and its native relatives in central Finland

    Directory of Open Access Journals (Sweden)

    A. KASURINEN

    2008-12-01

    Full Text Available Transmission electromicroscopy, trypan blue staining in combination with stereomicroscope analysis and biochemical ergosterol assay were used to study the mycorrhizal symbionts in wild bilberry (Vaccinium myrtillus, bog whortleberry (Vaccinium uliginosum and highbush blueberry (Vaccinium corymbosum roots. TEM-analysis showed that in all species ericoid mycorrhizas formed hyphae coil inside the epidermal root cells. In stereomicroscopic viewing the highest mycorrhizal colonisation was observed in the roots of wild bilberries (51%, whereas according to the ergosterol assay the highest total fungal biomass of roots was found in bog whortleberries (209 mg g-1 of root d. wt. Both ergosterol and microscopical method showed that the mycorrhizal associations in blueberry cultivars and their wild relatives growing on natural soil medium are frequent, although ericoid mycorrhiza formation of highbush blueberries was somewhat weaker than that of wild bilberries and bog whortleberries.

  18. Development of phylogenetic markers for Sebacina (Sebacinaceae) mycorrhizal fungi associated with Australian orchids.

    Science.gov (United States)

    Ruibal, Monica P; Peakall, Rod; Foret, Sylvain; Linde, Celeste C

    2014-06-01

    To investigate fungal species identity and diversity in mycorrhizal fungi of order Sebacinales, we developed phylogenetic markers. These new markers will enable future studies investigating species delineation and phylogenetic relationships of the fungal symbionts and facilitate investigations into evolutionary interactions among Sebacina species and their orchid hosts. • We generated partial genome sequences for a Sebacina symbiont originating from Caladenia huegelii with 454 genome sequencing and from three symbionts from Eriochilus dilatatus and one from E. pulchellus using Illumina sequencing. Six nuclear and two mitochondrial loci showed high variability (10-31% parsimony informative sites) for Sebacinales mycorrhizal fungi across four genera of Australian orchids (Caladenia, Eriochilus, Elythranthera, and Glossodia). • We obtained highly informative DNA markers that will allow investigation of mycorrhizal diversity of Sebacinaceae fungi associated with terrestrial orchids in Australia and worldwide.

  19. Effect of arbuscular mycorrhizal fungi and pesticides on Cynara cardunculus growth

    Directory of Open Access Journals (Sweden)

    M. MARIN

    2008-12-01

    Full Text Available Wild cardoon (Cynara cardunculus L. is a promising crop for biomass production. A nursery trial was conducted to investigate the effectiveness of mycorrhizal inoculation on the biomass yield of wild cardoon seedlings and the effect of the pesticides fosetyl-Al, folpet and propamocarb, as fungicides, and isofenphos, phoxim and oxamyl, as insecticides, on cardoon plant growth and the mycorrhization. The arbuscular mycorrhizal (AM fungi inocula were: commercial inoculum with Glomus mosseae spores, and an inoculum of a Glomus sp. strain (AMF-i isolated locally. Mycorrhizal inoculation with either inoculum increased cardoon shoot biomass compared to non-inoculated control plants. The pesticide applications had a neutral or positive effect on cardoon seedling growth. However, the AM fungi colonisation did not decrease except for plants colonised by G. mosseae and treated with the insecticides isofenphos and oxamyl. Thus, the mycorrhiza can survive to pesticide concentrations employed in commercial nursery, and enhance cardoon plant productivity.

  20. Infectivity of soilborne Frankia and mycorrhizae in Discaria trinervis along a vegetation gradient in Patagonian soil.

    Science.gov (United States)

    Chaia, Eugenia Esther; Fontenla, Sonia Beatriz; Vobis, Gernot; Wall, Luis Gabriel

    2006-01-01

    The infective capacities of the nitrogen fixing Actinomycete Frankia and arbuscular mycorrhizal fungi from soils near watercourses, along a vegetation gradient, were studied using plant bioassays. Frankia and arbuscular mycorrhizas capable of infecting Discaria trinervis were found at seventeen sites sampled. More specific enumeration of the infective capacities of both microorganisms in relation to environmental factors was performed in seven representative soils of the analysed vegetation zones (rainforest, xeric forest and steppe) using the most probable number method. The highest nodulation capacities ranged from 340 infective units g(-1 )soil, in a steppe marsh devoid of actinorhizas, to 61 in a coastal actinorhizal scrub (in xeric forest). The highest number of infective mycorrhizal units--also found in marsh--was 145. In general, rainforest soils had the lowest values for both microorganisms. Infective units of Frankia and arbuscular mycorrhizal fungi in soil were positively correlated (r = 0.89, P < 0.05). Both soilborne symbionts showed the highest infective capacity in semi-arid conditions nearby watercourse and at the valley bottom location. Tripartite symbiosis was effective in plants inoculated with steppe and xeric forest soils and plants inoculated with Frankia BCU110501 and Glomus mosseae. Interaction between both symbionts and influence of environmental conditions, in general, would contribute to define comparable trends of their infective capacities. ((c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

  1. Variation in mycorrhizal associations with tulasnelloid fungi among populations of five Dactylorhiza species.

    Science.gov (United States)

    Jacquemyn, Hans; Deja, Agnieszka; De hert, Koen; Cachapa Bailarote, Bruno; Lievens, Bart

    2012-01-01

    Orchid species rely on mycorrhizal symbioses with fungi to complete their life cycle. Although there is mounting evidence that orchids can associate with several fungi from different clades or families, less is known about the actual geographic distribution of these fungi and how they are distributed across different orchid species within a genus. We investigated among-population variation in mycorrhizal associations in five species of the genus Dactylorhiza (D. fuchsii, D. incarnata, D. maculata, D. majalis and D. praetermissa) using culture-independent detection and identification techniques enabling simultaneous detection of multiple fungi in a single individual. Mycorrhizal specificity, determined as the number of fungal operational taxonomic units (OTUs), and phylogenetic diversity of fungi were compared between species, whereas discriminant analysis was used to compare mycorrhizal spectra across populations and species. Based on a 95% cut-off value in internal transcribed spacer (ITS) sequence similarity, a total of ten OTUs was identified belonging to three different clades within the Tulasnellaceae. Most OTUs were found in two or more Dactylorhiza species, and some of them were common and widespread, occurring in more than 50% of all sampled populations. Each orchid species associated with at least five different OTUs, whereas most individuals also associated with two or more fungal OTUs at the same time. Phylogenetic diversity, corrected for species richness, was not significantly different between species, confirming the generality of the observed orchid mycorrhizal associations. We found that the investigated species of the genus Dactylorhiza associated with a wide range of fungal OTUs from the Tulasnellaceae, some of which were widespread and common. These findings challenge the idea that orchid rarity is related to mycorrhizal specificity and fungal distribution.

  2. Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Songlin [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycká 129, Prague 6−Suchdol 165 21 (Czech Republic); Zhang, Xin [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Sun, Yuqing; Wu, Zhaoxiang [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Li, Tao [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Hu, Yajun [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125 (China); Lv, Jitao; Li, Gang; Zhang, Zhensong [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Jing; Zheng, Lirong [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhen, Xiangjun [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); and others

    2016-10-05

    Highlights: • Cr immobilization in AM symbioses revealed by SEM-EDS, STXM and XAFS. • EPS like particles formed on fungal surface upon Cr(VI) stress. • Cr(VI) was reduced to mainly Cr(III)-phosphate analogues on fungal surface. • Cr can be retained by the intraradical fungal structures in mycorrhizal roots. - Abstract: Arbuscular mycorrhizal (AM) fungi can enhance plant Cr tolerance through immobilizing Cr in mycorrhizal roots. However, the detailed processes and mechanisms are unclear. The present study focused on cellular distribution and speciation of Cr in both extraradical mycelium (ERM) and mycorrhizal roots exposed to Cr(VI) by using field emission scanning electron microscopy equipped with energy dispersive X-ray spectrometer (FE-SEM-EDS), scanning transmission soft X-ray microscopy (STXM) and X-ray absorption fine structure (XAFS) spectroscopy techniques. We found that amounts of particles (possibly extracellular polymeric substances, EPS) were produced on the AM fungal surface upon Cr(VI) stress, which contributed greatly to Cr(VI) reduction and immobilization. With EDS of the surface of AM fungi exposed to various Cr(VI) levels, a positive correlation between Cr and P was revealed, suggesting that phosphate groups might act as counter ions of Cr(III), which was also confirmed by the XAFS analysis. Besides, STXM and XAFS analyses showed that Cr(VI) was reduced to Cr(III) in AM fungal structures (arbuscules, intraradical mycelium, etc.) and cell walls in mycorrhizal roots, and complexed possibly with carboxyl groups or histidine analogues. The present work provided evidence of Cr immobilization on fungal surface and in fungal structures in mycorrhizal roots at a cellular level, and thus unraveled the underlying mechanisms by which AM symbiosis immobilize Cr.

  3. Arbuscular mycorrhizal colonization in soil fertilized by organic and mineral fertilizers

    Science.gov (United States)

    Dvořáčková, Helena; Záhora, Jaroslav; Mikajlo, Irina; Elbl, Jakub; Kynický, Jindřich; Hladký, Jan; Brtnický, Martin

    2017-04-01

    The level of arbuscular mycorrhizal colonization of roots represents one of the best parameters for assessing soil quality. This special type of symbiosis helps plants to obtain nutrients of the distant area which are unavailable without cooperation with arbuscular mycorrhizal fungi. For example the plant available form of phosphorus is of the most important elements in plant nutrition. This element can't move (significantly) throw the soil and it could be unachievable for root system of plant. The same situation also applies to other important nutrients and water. Colonization of individual roots by arbuscular mycorrhizal fungi has a direct effect on the enlargement of the root system but plant needs to invest sugar substance for development of fungi. It's very difficult to understand when fungi colonization represents indicator of good soil condition. And when it provides us with information "about plant stress". The main goal of our work was to compare the effect of different fertilizers application on development of arbuscular mycorrhizal colonization. We worked with organic fertilizers such as biochar from residual biomass, biochar from sewage sludge and ageing biochar and with mineral fertilizer DAM 390 (mixture of ammonium 25 %, nitrate 25 % and urea nitrogen 50 %). Effect of different types of the above fertilizers on development of arbuscular mycorrhizal colonization was tested by pot experiment with indicator plant Lactuca sativa L. The highest (P < 0.05) colonization of roots was found in variant with biochar from sewage sludge. The lower colonization was recognized in control variant and variant with addition of mineral fertilizer. Our results indicate positive effect of modified biochar application to soil on increase in level of arbuscular mycorrhizal colonization of roots.

  4. The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Aloui, Achref; Recorbet, Ghislaine; Lemaître-Guillier, Christelle; Mounier, Arnaud; Balliau, Thierry; Zivy, Michel; Wipf, Daniel; Dumas-Gaudot, Eliane

    2017-07-19

    In arbuscular mycorrhizal (AM) roots, the plasma membrane (PM) of the host plant is involved in all developmental stages of the symbiotic interaction, from initial recognition to intracellular accommodation of intra-radical hyphae and arbuscules. Although the role of the PM as the agent for cellular morphogenesis and nutrient exchange is especially accentuated in endosymbiosis, very little is known regarding the PM protein composition of mycorrhizal roots. To obtain a global overview at the proteome level of the host PM proteins as modified by symbiosis, we performed a comparative protein profiling of PM fractions from Medicago truncatula roots either inoculated or not with the AM fungus Rhizophagus irregularis. PM proteins were isolated from root microsomes using an optimized discontinuous sucrose gradient; their subsequent analysis by liquid chromatography followed by mass spectrometry (MS) identified 674 proteins. Cross-species sequence homology searches combined with MS-based quantification clearly confirmed enrichment in PM-associated proteins and depletion of major microsomal contaminants. Changes in protein amounts between the PM proteomes of mycorrhizal and non-mycorrhizal roots were monitored further by spectral counting. This workflow identified a set of 82 mycorrhiza-responsive proteins that provided insights into the plant PM response to mycorrhizal symbiosis. Among them, the association of one third of the mycorrhiza-responsive proteins with detergent-resistant membranes pointed at partitioning to PM microdomains. The PM-associated proteins responsive to mycorrhization also supported host plant control of sugar uptake to limit fungal colonization, and lipid turnover events in the PM fraction of symbiotic roots. Because of the depletion upon symbiosis of proteins mediating the replacement of phospholipids by phosphorus-free lipids in the plasmalemma, we propose a role of phosphate nutrition in the PM composition of mycorrhizal roots.

  5. Conditions Promoting Mycorrhizal Parasitism are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Directory of Open Access Journals (Sweden)

    Martina Friede

    2016-09-01

    Full Text Available Interactions of plants with arbuscular mycorrhizal fungi (AMF may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD of a plant and in consequence may play an important role in plant-plant interactions.In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic.Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant

  6. Conditions Promoting Mycorrhizal Parasitism Are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Science.gov (United States)

    Friede, Martina; Unger, Stephan; Hellmann, Christine; Beyschlag, Wolfram

    2016-01-01

    Interactions of plants with arbuscular mycorrhizal fungi (AMF) may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD) of a plant and in consequence may play an important role in plant-plant interactions. In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic. Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant control over

  7. Common arbuscular mycorrhizal networks amplify competition for phosphorus between seedlings and established plants

    DEFF Research Database (Denmark)

    Merrild, Marie Porret; Ambus, Per; Rosendahl, Søren

    2013-01-01

    Common mycorrhizal networks (CMNs) influence competition between plants, but reports regarding their precise effect are conflicting. We studied CMN effects on phosphorus (P) uptake and growth of seedlings as influenced by various disruptions of network components. Tomato (Solanum lycopersicon...... or severed arbuscular mycorrhizal fungus networks and at two soil P concentrations. Pre‐established and intact networks suppressed growth of tomato seedlings. Cutting of cucumber shoots mitigated P deficiency symptoms of seedlings, which obtained access to P in the extraradical mycelium and thereby showed...

  8. Ploidy-specific symbiotic interactions: divergence of mycorrhizal fungi between cytotypes of the Gymnadenia conopsea group (Orchidaceae).

    Science.gov (United States)

    Těšitelová, Tamara; Jersáková, Jana; Roy, Mélanie; Kubátová, Barbora; Těšitel, Jakub; Urfus, Tomáš; Trávníček, Pavel; Suda, Jan

    2013-09-01

    Polyploidy is widely recognized as a major mechanism of sympatric speciation in plants, yet little is known about its effects on interactions with other organisms. Mycorrhizal fungi are among the most common plant symbionts and play an important role in plant nutrient supply. It remains to be understood whether mycorrhizal associations of ploidy-variable plants can be ploidy-specific. We examined mycorrhizal associations in three cytotypes (2x, 3x, 4x) of the Gymnadenia conopsea group (Orchidaceae), involving G. conopsea s.s. and G. densiflora, at different spatial scales and during different ontogenetic stages. We analysed: adults from mixed- and single-ploidy populations at a regional scale; closely spaced adults within a mixed-ploidy site; and mycorrhizal seedlings. All Gymnadenia cytotypes associated mainly with saprotrophic Tulasnellaceae (Basidiomycota). Nonetheless, both adults and seedlings of diploids and their autotetraploid derivatives significantly differed in the identity of their mycorrhizal symbionts. Interploidy segregation of mycorrhizal symbionts was most pronounced within a site with closely spaced adults. This study provides the first evidence that polyploidization of a plant species can be associated with a shift in mycorrhizal symbionts. This divergence may contribute to niche partitioning and facilitate establishment and co-existence of different cytotypes. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  9. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Liu, Lingzhi; Gong, Zongqiang; Zhang, Yulong; Li, Peijun

    2014-12-01

    The effects of three arbuscular mycorrhizal fungi isolates on Cd uptake and accumulation by maize (Zea mays L.) were investigated in a planted pot experiment. Plants were inoculated with Glomus intraradices, Glomus constrictum and Glomus mosseae at three different Cd concentrations. The results showed that root colonization increased with Cd addition during a 6-week growth period, however, the fungal density on roots decreased after 9-week growth in the treatments with G. constrictum and G. mosseae isolates. The percentage of mycorrhizal colonization by the three arbuscular mycorrhizal fungi isolates ranged from 22.7 to 72.3%. Arbuscular mycorrhizal fungi inoculations decreased maize biomass especially during the first 6-week growth before Cd addition, and this inhibitory effect was less significant with Cd addition and growth time. Cd concentrations and uptake in maize plants increased with arbuscular mycorrhizal fungi colonization at low Cd concentration (0.02 mM): nonetheless, it decreased at high Cd concentration (0.20 mM) after 6-week growth period. Inoculation with G. constrictum isolates enhanced the root Cd concentrations and uptake, but G. mosseae isolates showed the opposite results at high Cd concentration level after 9 week growth period, as compared to non-mycorrhizal plants. In conclusion, maize plants inoculated with arbuscular mycorrhizal fungi were less sensitive to Cd stress than uninoculated plants. G. constrictum isolates enhanced Cd phytostabilization and G. mosseae isolates reduced Cd uptake in maize (Z. mays L.).

  10. Low specificity and nested subset structure characterize mycorrhizal associations in five closely related species of the genus Orchis.

    Science.gov (United States)

    Jacquemyn, Hans; Honnay, Olivier; Cammue, Bruno P A; Brys, Rein; Lievens, Bart

    2010-09-01

    Most orchid species rely on mycorrhizae to complete their life cycle. Despite a growing body of literature identifying orchid mycorrhizal associations, the nature and specificity of the association between orchid species and mycorrhizal fungi remains largely an open question. Nonetheless, better insights into these obligate plant-fungus associations are indispensable for understanding the biology and conservation of orchid populations. To investigate orchid mycorrhizal associations in five species of the genus Orchis (O. anthropophora, O. mascula, O. militaris, O. purpurea, and O. simia), we developed internal transcribed spacer-based DNA arrays from extensive clone library sequence data sets, enabling rapid and simultaneous detection of a wide range of basidiomycetous mycorrhizal fungi. A low degree of specificity was observed, with two orchid species associating with nine different fungal partners. Phylogenetic analysis revealed that the majority of Orchis mycorrhizal fungi are members of the Tulasnellaceae, but in some plants, members of the Thelephoraceae, Cortinariaceae and Ceratobasidiaceae were also found. In all species except one (O. mascula), individual plants associated with more than one fungus simultaneously, and in some cases, associations with ≥3 mycorrhizal fungi at the same time were identified. Nestedness analysis showed that orchid mycorrhizal associations were significantly nested, suggesting asymmetric specialization and a dense core of interactions created by symmetric interactions between generalist species. Our results add support to the growing literature that multiple associations may be common among orchids. Low specificity or preference for a widespread fungal symbiont may partly explain the wide distribution of the investigated species. © 2010 Blackwell Publishing Ltd.

  11. The symbiosis with the arbuscular mycorrhizal fungus Rhizophagus irregularis drives root water transport in flooded tomato plants.

    Science.gov (United States)

    Calvo-Polanco, Monica; Molina, Sonia; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

    2014-05-01

    It is known that the presence of arbuscular mycorrhizal fungi within the plant roots enhances the tolerance of the host plant to different environmental stresses, although the positive effect of the fungi in plants under waterlogged conditions has not been well studied. Tolerance of plants to flooding can be achieved through different molecular, physiological and anatomical adaptations, which will affect their water uptake capacity and therefore their root hydraulic properties. Here, we investigated the root hydraulic properties under non-flooded and flooded conditions in non-mycorrhizal tomato plants and plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. Only flooded mycorrhizal plants increased their root hydraulic conductivity, and this effect was correlated with a higher expression of the plant aquaporin SlPIP1;7 and the fungal aquaporin GintAQP1. There was also a higher abundance of the PIP2 protein phoshorylated at Ser280 in mycorrhizal flooded plants. The role of plant hormones (ethylene, ABA and IAA) in root hydraulic properties was also taken into consideration, and it was concluded that, in mycorrhizal flooded plants, ethylene has a secondary role regulating root hydraulic conductivity whereas IAA may be the key hormone that allows the enhancement of root hydraulic conductivity in mycorrhizal plants under low oxygen conditions.

  12. Quantification of the proliferation of arbuscular mycorrhizal fungi in soil

    Science.gov (United States)

    Zhang, Ning; Lilje, Osu; McGee, Peter

    2013-04-01

    Good soil structure is important for sustaining agricultural production and preserving functions of the soil ecosystem. Soil aggregation is a critically important component of soil structure. Stable aggregates enable water infiltration, gas exchange for biological activities of plant roots and microorganisms, living space and surfaces for soil microbes, and contribute to stabilization of organic matter and storage of organic carbon (OC) in soil. Soil aggregation involves fine roots, organic matter and hyphae of arbuscular mycorrhizal (AM) fungi. Hyphal proliferation is essential for soil aggregation and sequestration of OC in soil. We do not yet have a mechanism to directly quantify the density of hyphae in soil. Organic materials and available phosphorus are two of the major factors that influence fungi in soil. Organic materials are a source of energy for saprotrophic microbes. Fungal hyphae increase in the presence of organic matter. Phosphorus is an important element usually found in ecosystems. The low availability of phosphorus limits the biological activity of microbes. AM fungi benefit plants by delivering phosphorus to the root system. However, the density and the length of hyphae of AM fungi do not appear to be influenced by available phosphorus. A number of indirect methods have been used to visualize distribution of fungi in soil. Reliable analyses of soil are limited because of soil characteristics. Soils are fragile, and fragility limits opportunity for non-destructive analysis. The soil ecosystem is complex. Soil particles are dense and the density obscures the visualization of fungal hyphae. Fungal hyphae are relatively fine and information at the small scale (attached to the surfaces of the particles rather than grow through the spaces between them. The capacity to quantify hyphae in three-dimensional space allows a wide range of questions to now be addressed. Apart from studying mechanisms of carbon turnover, more complex processes may now be

  13. Arbuscular mycorrhizal fungi (Glomales, Zygomycota of the Bledowska Desert, Poland

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-01-01

    Full Text Available The occurrence of arbuscular mycorrhizal fungi (AMF; Glomales, Zygomycetes associated with plants growing in sand dune soils of the Blędowska Desert, Poland, was investigated in 1995-1997. A total of 134 mixtures of soils and roots were sampled. The mixtures represented 26 plant species in 14 families and one unrecognized plant. Spores of AMF were found in 118 soil-root mixtures. The AMF spore populations comprised 20 described species of the genera Acaulospora, Gigaspora, Glomus and Scutellospora, as well as two undescribed morphospecies of the genus Glomus. The AMF most frequently occurring in the field-collected soils were members of the genus Scutellospora The AMF spore populations comprised 20 described species in the genera Acaulospora, Gigaspora, Glomus and Scutellospora, as well as two undescribed morpho-species of the genus Glomus. The fungal species most frequently and numerously found was Scutellospora armeniaca. The fungi relatively frequently present also were A. rugosa, A. lacunosa, G. aggregatum, an undescribed Glomus 142 and Sc. dipurpurescens. The overall spore abundance of AMF averaged 69.1 and ranged from 0 to 837 in 100 g dry soil. The highest abundance of spores occurred among roots of the families Cupressaceae, followed by the Rosaceae, Asteraceae and Poaceae. Of the plant species investigated two and more times, most spores harboured Juniperus communis. The overall average species richness was 2.4 and ranged from 0 to 6 in 100 g dry soil. Of the plant species sampled at lest two times, the highest average species diversity was found in the root zone of Salix arenaria. The plant species that hosted the highest overall number of species of AMF was Festuca rubra. Trap pot cultures with soilroot mixtures collected in 1997 revealed 10 species of AMF that were not found in field soils sampled in the same year. This suggests that a great part of AMF of Błędowska Desert is represented by rarely or non-sporulating species.

  14. Development of soil quality metrics using mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Baar, J.

    2010-07-01

    Based on the Treaty on Biological Diversity of Rio de Janeiro in 1992 for maintaining and increasing biodiversity, several countries have started programmes monitoring soil quality and the above- and below ground biodiversity. Within the European Union, policy makers are working on legislation for soil protection and management. Therefore, indicators are needed to monitor the status of the soils and these indicators reflecting the soil quality, can be integrated in working standards or soil quality metrics. Soil micro-organisms, particularly arbuscular mycorrhizal fungi (AMF), are indicative of soil changes. These soil fungi live in symbiosis with the great majority of plants and are sensitive to changes in the physico-chemical conditions of the soil. The aim of this study was to investigate whether AMF are reliable and sensitive indicators for disturbances in the soils and can be used for the development of soil quality metrics. Also, it was studied whether soil quality metrics based on AMF meet requirements to applicability by users and policy makers. Ecological criterions were set for the development of soil quality metrics for different soils. Multiple root samples containing AMF from various locations in The Netherlands were analyzed. The results of the analyses were related to the defined criterions. This resulted in two soil quality metrics, one for sandy soils and a second one for clay soils, with six different categories ranging from very bad to very good. These soil quality metrics meet the majority of requirements for applicability and are potentially useful for the development of legislations for the protection of soil quality. (Author) 23 refs.

  15. Water deficit improved the capacity of arbuscular mycorrhizal fungi (AMF) for inducing the accumulation of antioxidant compounds in lettuce leaves.

    Science.gov (United States)

    Baslam, Marouane; Goicoechea, Nieves

    2012-07-01

    Lettuce, a major food crop within the European Union and the most used for the so-called 'Fourth Range' of vegetables, can associate with arbuscular mycorrhizal fungi (AMF). Mycorrhizal symbiosis can stimulate the synthesis of secondary metabolites, which may increase plant tolerance to stresses and enhance the accumulation of antioxidant compounds potentially beneficial to human health. Our objectives were to assess (1) if the application of a commercial formulation of AMF benefited growth of lettuce under different types and degrees of water deficits; (2) if water restrictions affected the nutritional quality of lettuce; and (3) if AMF improved the quality of lettuce when plants grew under reduced irrigation. Two cultivars of lettuce consumed as salads, Batavia Rubia Munguía and Maravilla de Verano, were used in the study. Four different water regimes were applied to both non-mycorrhizal and mycorrhizal plants: optimal irrigation (field capacity [FC]), a water regime equivalent to 2/3 of FC, a water regime equivalent to 1/2 of FC and a cyclic drought (CD). Results showed that mycorrhizal symbiosis improved the accumulation of antioxidant compounds, mainly carotenoids and anthocyanins, and to a lesser extent chlorophylls and phenolics, in leaves of lettuce. These enhancements were higher under water deficit than under optimal irrigation. Moreover, shoot biomass in mycorrhizal lettuces subjected to 2/3 of FC were similar to those of non-mycorrhizal plants cultivated under well-watered conditions. In addition, lettuces subjected to 2/3 FC had similar leaf RWC than their respective well-watered controls, regardless of mycorrhizal inoculation. Therefore, results suggest that mycorrhizal symbiosis can improve quality of lettuce and may allow restrict irrigation without reducing production.

  16. Highly diverse and spatially heterogeneous mycorrhizal symbiosis in a rare epiphyte is unrelated to broad biogeographic or environmental features.

    Science.gov (United States)

    Kartzinel, Tyler R; Trapnell, Dorset W; Shefferson, Richard P

    2013-12-01

    Symbiotic interactions are common in nature. In dynamic or degraded environments, the ability to associate with multiple partners (i.e. broad specificity) may enable species to persist through fluctuations in the availability of any particular partner. Understanding how species interactions vary across landscapes is necessary to anticipate direct and indirect consequences of environmental degradation on species conservation. We asked whether mycorrhizal symbiosis by populations of a rare epiphytic orchid (Epidendrum firmum) is related to geographic or environmental heterogeneity. The latter would suggest that interactions are governed by environmental conditions rather than historic isolation of populations and/or mycorrhizal fungi. We used DNA-based methods to identify mycorrhizal fungi from eleven E. firmum populations in Costa Rica. We used molecular and phylogenetic analyses to compare associations. Epidendrum firmum exhibited broad specificity, associating with diverse mycorrhizal fungi, including six Tulasnellaceae molecular operational taxonomic units (MOTUs), five Sebacinales MOTUs and others. Notably, diverse mycorrhizal symbioses formed in disturbed pasture and roadside habitats. Mycorrhizal fungi exhibited significant similarity within populations (spatial and phylogenetic autocorrelation) and significant differences among populations (phylogenetic community dissimilarity). However, mycorrhizal symbioses were not significantly associated with biogeographic or environmental features. Such unexpected heterogeneity among populations may result from complex combinations of fine-scale environmental factors and macro-evolutionary patterns of change in mycorrhizal specificity. Thus, E. firmum exhibits broad specificity and the potential for opportunistic associations with diverse fungi. We suggest that these characteristics could confer symbiotic assurance when mycorrhizal fungi are stochastically available, which may be crucial in dynamic or disturbed

  17. Can we develop general predictive models of mycorrhizal fungal community-environment relationships?

    Science.gov (United States)

    Erik A. Lilleskov; Jeri L. Parrent

    2007-01-01

    Our understanding of the controls on mycorrhizal fungal species distribution and community organization is in its early childhood - especially when compared with that of the more mature fields of plant and animal community ecology and biogeography - largely because of the historical difficulty of gathering species distribution information.

  18. Foliar Application of Phosphorus Has Minimal Impact on 'Pinot noir' Growth, Mycorrhizal Colonization, or Fruit Quality

    Science.gov (United States)

    Grapevines grown in low phosphorus (P) soils typical of western Oregon vineyards may benefit from additional P applied to the canopy using foliar sprays. Alternatively, vines may be negatively affected by foliar P sprays because lower root colonization by arbuscular mycorrhizal fungi (AMF) could red...

  19. Arbuscular mycorrhizal fungi colonize non-fixing root nodules of several legume species.

    NARCIS (Netherlands)

    Scheublin, T.R.; van der Heijden, M.G.A.

    2006-01-01

    • Many legumes form tripartite symbiotic associations with rhizobia and arbuscular mycorrhizal fungi (AMF). Rhizobia are located in root nodules and provide the plant with fixed atmospheric nitrogen, while AMF colonize plant roots and deliver several essential nutrients to the plant. Recent studies

  20. Arbuscular mycorrhizal fungi colonize nonfixing roots nodules of several legume species.

    NARCIS (Netherlands)

    Scheublin, T.R.; van der Heijden, M.G.A.

    2006-01-01

    • Many legumes form tripartite symbiotic associations with rhizobia and arbuscular mycorrhizal fungi (AMF). Rhizobia are located in root nodules and provide the plant with fixed atmospheric nitrogen, while AMF colonize plant roots and deliver several essential nutrients to the plant. Recent studies

  1. Inoculation of grass and tree seedlings used for reclaiming eroded areas in Iceland with mycorrhizal dungi

    Czech Academy of Sciences Publication Activity Database

    Batkhuugyin, Enkhtuya; Óskarsson, Ú.; Dodd, J. C.; Vosátka, Miroslav

    2003-01-01

    Roč. 38, - (2003), s. 209-222 ISSN 0015-5551 R&D Projects: GA AV ČR KSK6005114; GA ČR GA526/99/0895 Institutional research plan: CEZ:AV0Z6005908 Keywords : arbuscular mycorrhizal fungi * ectomycorrhizal fungi * volcanic ash Subject RIV: EF - Botanics Impact factor: 1.057, year: 2003

  2. Mycorrhizal responsiveness of aerobic rice genotypes is negatively correlated with their zinc uptake when nonmycorhizal

    NARCIS (Netherlands)

    Gao, X.; Kuyper, T.W.; Zou, C.; Zhang, F.; Hoffland, E.

    2007-01-01

    Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processes. We studied whether inoculation with arbuscular mycorrhizal fungi (AMF) can be an additional or an alternative strategy. We determined the effect of AMF inoculation on growth performance and Zn uptake

  3. Variation in phosphorus acquisition efficiency among maize varieties as related to mycorrhizal functioning

    NARCIS (Netherlands)

    Wang, X.X.

    2016-01-01

    Phosphorus (P) is a main limiting factor for agricultural production, but overusing P fertilizer has brought serious environmental damages in China. Improving P acquisition efficiency of agricultural crops is an urgent topic. It has been proven repeatedly that arbuscular mycorrhizal fungi (AMF) and

  4. Efflux of hydraulically lifted water from mycorrhizal fungal hyphae during imposed drought

    Science.gov (United States)

    Querejeta, José Ignacio; Allen, Michael F

    2008-01-01

    Apart from improving plant and soil water status during drought, it has been suggested that hydraulic lift (HL) could enhance plant nutrient capture through the flow of mineral nutrients directly from the soil to plant roots, or by maintaining the functioning of mycorrhizal fungi. We evaluated the extent to which the diel cycle of water availability created by HL covaries with the efflux of HL water from the tips of extramatrical (external) mycorrhizal hyphae, and the possible effects on biogeochemical processes. Phenotypic mycorrhizal fungal variables, such as total and live hyphal lengths, were positively correlated with HL efflux from hyphae, soil water potential (dawn), and plant response variables (foliar 15N). The efflux of HL water from hyphae was also correlated with bacterial abundance and soil enzyme activity (P), and the moistening of soil organic matter. Such findings indicate that the efflux of HL water from the external mycorrhizal mycelia may be a complementary explanation for plant nutrient acquisition and survival during drought. PMID:19704776

  5. Facilitation between woody and herbaceous plants that associate with arbuscular mycorrhizal fungi in temperate European forests.

    Science.gov (United States)

    Veresoglou, Stavros D; Wulf, Monika; Rillig, Matthias C

    2017-02-01

    In late-successional environments, low in available nutrient such as the forest understory, herbaceous plant individuals depend strongly on their mycorrhizal associates for survival. We tested whether in temperate European forests arbuscular mycorrhizal (AM) woody plants might facilitate the establishment of AM herbaceous plants in agreement with the mycorrhizal mediation hypothesis. We used a dataset spanning over 400 vegetation plots in the Weser-Elbe region (northwest Germany). Mycorrhizal status information was obtained from published resources, and Ellenberg indicator values were used to infer environmental data. We carried out tests for both relative richness and relative abundance of herbaceous plants. We found that the subset of herbaceous individuals that associated with AM profited when there was a high cover of AM woody plants. These relationships were retained when we accounted for environmental filtering effects using path analysis. Our findings build on the existing literature highlighting the prominent role of mycorrhiza as a coexistence mechanism in plant communities. From a nature conservation point of view, it may be possible to promote functional diversity in the forest understory through introducing AM woody trees in stands when absent.

  6. Indicator species and co-occurrence in communities of arbuscular mycorrhizal fungi at the European scale

    NARCIS (Netherlands)

    Bouffaud, Marie Lara; Creamer, Rachel E.; Stone, Dote; Plassart, Pierre; Tuinen, van Diederik; Lemanceau, Philippe; Wipf, Daniel; Redecker, Dirk

    2016-01-01

    Utilizing a European transect of 54 soil samples, comprising of grasslands, arable and forest sites, we analyzed community composition of Arbuscular Mycorrhizal Fungi (AMF, Glomeromycota) using pyrosequencing of the Internal Transcribed Spacer region. We found a significant influence of

  7. Mycorrhizal symbiosis and seedling performance of the frankincense tree (Boswellia papyrifera)

    NARCIS (Netherlands)

    Hizikias, E.B.

    2011-01-01

    Arid areas are characterized by a seasonal climate with a long dry period. In such stressful environment, resource availability is driven by longterm and shorterm rainfall pulses. Arbuscular Mycorrhizal (AM) fungi enhance access to moisture and nutrients and thereby influence plant performance.

  8. BIOMETRIC PARAMETERS OF FIELD GROWN SESAME INFLUENCED BY ARBUSCULAR MYCORRHIZAL INOCULATION, ROCK PHOSPHATE FERTILIZATION AND IRRIGATION

    Directory of Open Access Journals (Sweden)

    V.S. Harikumar

    2017-08-01

    Full Text Available The aim of the study was to assess the effect of inoculation with arbuscular mycorrhizal fungi (AMF and rock phosphate (RP fertilization on biometric parameters and mycorrhizal colonization of field grown sesame under rainfed and irrigated conditions. Inoculation of AMF Funneliformis dimorphicus improved the biometric parameters of the crop such as leaf area (LA, leaf area index (LAI, specific leaf weight (SLW, net assimilation rate (NAR, oil index (OI as well as mycorrhizal colonization (%F in roots. Mycorrhizal inoculation however, did not give any positive response on harvest index (HI. LA, LAI and OI and %F showed a general increment in treatments of no added P (P0, while the other parameters such as SLW and NAR were improved by the application of RP at half the recommended dose (P50. HI did not respond to RP fertilization. Most of the parameters (LA, LAI, NAR, %F showed higher values under rainfed condition than irrigated condition whereas, SLW, HI and OI improved significantly under irrigated condition. Results indicated that the inoculation of AMF to field grown sesame can compensate for 50% of the recommended P fertilizer under a need based irrigation schedule, without affecting the biometric parameters.

  9. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato

    NARCIS (Netherlands)

    Ruiz-Lozano, J.M.; Aroca, R.; Zamarreno, A.M.; Molina, S.; Andreo Jimenez, B.; Porcel, R.; Garcia-Mina, J.M.; Ruyter-Spira, C.P.; Lopez-Raez, J.A.

    2016-01-01

    Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant–AM fungus interaction remains largely unknown. In the present work, the effects of

  10. Arbuscular mycorrhizal fungal species differ in their effect on nutrient leaching

    NARCIS (Netherlands)

    Köhl, Luise; van der Heijden, Marcel G A

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi have been shown to play a crucial role in nutrient cycling and can reduce nutrient losses after rain induced leaching events. It is still unclear whether nutrient leaching losses vary depending on the AM fungal taxa that are present in soil. Using experimental

  11. Mycorrhizal associations in Ailanthus altissima (Simaroubaceae) from forested and non-forested sites

    Science.gov (United States)

    Cynthia D. Huebner; Carolyn McQuattie; Joanne Rebbeck

    2007-01-01

    Ailanthus altissima tree seedlings were excavated from each of two habitats: (1) a forest adjacent to a trail and stream and (2) a non-forested steep, barren slope adjacent to a major highway. Each seedling root system was examined for colonization by mycorrhizal structures using light microscopy and transmission electron microscopy. The roots were...

  12. Arbuscular mycorrhizal symbiosis alleviates drought stress imposed on Knautia arvensis plants in serpentine soil

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Vlasáková, E.; Sudová, Radka

    2013-01-01

    Roč. 370, 1-2 (2013), s. 149-161 ISSN 0032-079X R&D Projects: GA AV ČR KJB600050812 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * drought * serpentine soil Subject RIV: EF - Botanics Impact factor: 3.235, year: 2013

  13. Carbon flow from plant to arbuscular mycorrhizal fungi is reduced under phosphorus fertilization

    Czech Academy of Sciences Publication Activity Database

    Konvalinková, Tereza; Püschel, David; Řezáčová, Veronika; Gryndlerová, Hana; Jansa, Jan

    2017-01-01

    Roč. 419, 1-2 (2017), s. 319-333 ISSN 0032-079X R&D Projects: GA MŠk(CZ) LK11224; GA ČR(CZ) GA14-19191S Institutional support: RVO:61388971 Keywords : Arbuscular mycorrhiza * Carbon allocation * Mycorrhizal cost Subject RIV: EE - Microbiology, Virology Impact factor: 3.052, year: 2016

  14. Decomposition of /sup 14/C-labelled lignin, holocellulose and lignocellulose by mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Trojanowski, J.; Huettermann, A.; Haider, K.

    1984-01-01

    Five different species of known ecto-mycorrhizal fungi: Cenococcum geophilum, Amanita muscaria, Tricholoma aurantium, Rhizopogon luteolus and Rhizopogon roseolus were studied for their ability to metabolize the major components of plant cell walls. All strains were able to decompose /sup 14/C-labelled plant lignin, /sup 14/C-lignocellulose and /sup 14/C-DHP-lignin at a rate which was lower than the one observed for the known white rot fungi Heterobasidion annosum and Sporotrichum pulverulentum. Also /sup 14/C-(U)-holocellulose was relatively less degradable for the mycorrhizal fungi than for the white rotters. On the other hand, aromatic monomers like /sup 14/C-vanillic acid were decomposed to a much higher extent by two species of mycorrhizal fungi compared to the activity observed for Heterobasidion annosum. The results of the experiments reveal that these stains of mycorrhizal fungi are well able to utilize the major components of plant material and thus can contribute to litter decomposition in the forest floor.

  15. The scion/rootstock genotypes and habitats affect arbuscular mycorrhizal fungal community in citrus

    NARCIS (Netherlands)

    Song, Fang; Pan, Zhiyong; Bai, Fuxi; An, Jianyong; Liu, Jihong; Guo, Wenwu; Bisseling, Ton; Deng, Xiuxin; Xiao, Shunyuan

    2015-01-01

    Citrus roots have rare root hairs and thus heavily depend on arbuscular mycorrhizal fungi (AMF) for mineral nutrient uptake. However, the AMF community structure of citrus is largely unknown. By using 454-pyrosequencing of 18S rRNA gene fragment, we investigated the genetic diversity of AMF

  16. Community structure of arbuscular mycorrhizal fungi in undisturbed vegetation revealed by analyses of LSU rdna sequences

    DEFF Research Database (Denmark)

    Rosendahl, Søren; Holtgrewe-Stukenbrock, Eva

    2004-01-01

    Arbuscular mycorrhizal fungi (AMF) form a mutualistic symbiosis with plant roots and are found in most ecosystems. In this study the community structure of AMF in a clade of the genus Glomus was examined in undisturbed costal grassland using LSU rDNA sequences amplified from roots of Hieracium...

  17. Arbuscular mycorrhizal fungi differentially affect the response to high zinc concentrations of two registered poplar clones

    Energy Technology Data Exchange (ETDEWEB)

    Lingua, Guido [Dipartimento di Scienze dell' Ambiente e della Vita, Universita del Piemonte Orientale ' Amedeo Avogadro' , Via Bellini 25/G, I-15100 Alessandria (Italy)], E-mail: guido.lingua@mfn.unipmn.it; Franchin, Cinzia [Dipartimento di Biologia evoluzionistica sperimentale, Universita di Bologna, Via Irnerio 42, I-40126 Bologna (Italy); Todeschini, Valeria [Dipartimento di Scienze dell' Ambiente e della Vita, Universita del Piemonte Orientale ' Amedeo Avogadro' , Via Bellini 25/G, I-15100 Alessandria (Italy); Castiglione, Stefano [Dipartimento di Biologia, Universita di Milano, Via Celoria 25, I-20100 Milano (Italy); Biondi, Stefania [Dipartimento di Biologia evoluzionistica sperimentale, Universita di Bologna, Via Irnerio 42, I-40126 Bologna (Italy); Burlando, Bruno [Dipartimento di Scienze dell' Ambiente e della Vita, Universita del Piemonte Orientale ' Amedeo Avogadro' , Via Bellini 25/G, I-15100 Alessandria (Italy); Parravicini, Valerio [Dipartimento di Biologia, Universita di Milano, Via Celoria 25, I-20100 Milano (Italy); Torrigiani, Patrizia [Dipartimento di Biologia evoluzionistica sperimentale, Universita di Bologna, Via Irnerio 42, I-40126 Bologna (Italy); Berta, Graziella [Dipartimento di Scienze dell' Ambiente e della Vita, Universita del Piemonte Orientale ' Amedeo Avogadro' , Via Bellini 25/G, I-15100 Alessandria (Italy)

    2008-05-15

    The effects of a high concentration of zinc on two registered clones of poplar (Populus alba Villafranca and Populus nigra Jean Pourtet), inoculated or not with two arbuscular mycorrhizal fungi (Glomus mosseae or Glomus intraradices) before transplanting them into polluted soil, were investigated, with special regard to the extent of root colonization by the fungi, plant growth, metal accumulation in the different plant organs, and leaf polyamine concentration. Zinc accumulation was lower in Jean Pourtet than in Villafranca poplars, and it was mainly translocated to the leaves; the metal inhibited mycorrhizal colonization, compromised plant growth, and, in Villafranca, altered the putrescine profile in the leaves. Most of these effects were reversed or reduced in plants pre-inoculated with G. mosseae. Results indicate that poplars are suitable for phytoremediation purposes, confirming that mycorrhizal fungi can be useful for phytoremediation, and underscore the importance of appropriate combinations of plant genotypes and fungal symbionts. - Inoculation with arbuscular mycorrhizal fungi can improve poplar tolerance to heavy metals in phytoremediation programmes.

  18. An exotic grass disrupts mycorrhizal fungi which increases the mortality of Artemisia tridentata

    Science.gov (United States)

    Invasive plant species are capable of changing the community composition of arbuscular mycorrhizal fungi (AMF). Changes to AMF communities may contribute to the net negative impact of invasives on resident plants. Here we compared the AMF communities of the invasive grass Agropyron cristatum acros...

  19. Mycorrhizal associations of trees have different indirect effects on organic matter decomposition

    Science.gov (United States)

    Melanie K. Taylor; Richard A. Lankau; Nina Wurzburger; Franciska de Vries

    2016-01-01

    1. Organic matter decomposition is the main process by which carbon (C) is lost from terrestrialecosystems, and mycorrhizal associations of plants (i.e. arbuscular mycorrhizas (AM) and ectomycorrhizas(ECM)) may have different indirect effects on this loss pathway. AM and ECM plants differin the soil...

  20. Inoculation of fumigated nursery beds and containers with arbuscular mycorrhizal products for eastern redcedar production

    Science.gov (United States)

    Michelle M. Cram; Stephen W. Fraedrich

    2015-01-01

    Commercially available arbuscular mycorrhizal (AM) products were applied at an operational rate to eastern redcedar (Juniperus virginiana L.) nursery beds and containers to evaluate seedling growth and colonization responses. A field study at the Augusta Forestry Center in Crimora, VA, and a companion container study were initiated in the fall of 2012. MycoApply® Endo...

  1. Effect of biochar soil-amendments on Allium porrum growth, arbuscular mycorrhizal fungus colonization

    Science.gov (United States)

    Aims: Examine the interaction of biochar addition and arbuscular mycorrhizal [AM] fungus inoculation upon growth and Zn and Cu uptake by Allium porrum L. in heavy metal amended soil mix, and relate these responses to physicochemical properties of the biochars. Methods: The experiment was a complete ...

  2. Establishment and effectiveness of inoculated arbuscular mycorrhizal fungi in agricultural soils

    NARCIS (Netherlands)

    Köhl, Luise; Lukasiewicz, Catherine E.; Van der Heijden, Marcel G A|info:eu-repo/dai/nl/240923901

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are promoted as biofertilizers for sustainable agriculture. So far, most researchers have investigated the effects of AMF on plant growth under highly controlled conditions with sterilized soil, soil substrates or soils with low available P or low inoculum

  3. Mycorrhizal ecology and evolution : The past, the present, and the future

    NARCIS (Netherlands)

    van der Heijden, Marcel G A|info:eu-repo/dai/nl/240923901; Martin, Francis M.; Selosse, Marc André; Sanders, Ian R.

    2015-01-01

    Almost all land plants form symbiotic associations with mycorrhizal fungi. These below-ground fungi play a key role in terrestrial ecosystems as they regulate nutrient and carbon cycles, and influence soil structure and ecosystem multifunctionality. Up to 80% of plant N and P is provided by

  4. Mycorrhizal Fungal Community of Poplars Growing on Pyrite Tailings Contaminated Site near the River Timok

    Directory of Open Access Journals (Sweden)

    Marina Katanić

    2015-06-01

    Full Text Available Background and Purpose: Mycorrhizal fungi are of high importance for functioning of forest ecosystems and they could be used as indicators of environmental stress. The aim of this research was to analyze ectomycorrhizal community structure and to determine root colonization rate with ectomycorrhizal, arbuscular mycorrhizal and endophytic fungi of poplars growing on pyrite tailings contaminated site near the river Timok (Eastern Serbia. Materials and Methods: Identification of ectomycorrhizal types was performed by combining morphological and anatomical characterization of ectomycorrhizae with molecular identification approach, based on sequencing of the nuclear ITS rRNA region. Also, colonization of poplar roots with ectomycorrhizal, arbuscular mycorrhizal and dark septated endophytic fungi were analysed with intersection method. Results and Conclusions: Physico-chemical analyses of soil from studied site showed unfavourable water properties of soil, relatively low pH and high content of heavy metals (copper and zinc. In investigated samples only four different ectomycorrhizal fungi were found. To the species level were identified Thelephora terrestris and Tomentella ellisi, while two types remained unidentified. Type Thelephora terrestris made up 89% of all ectomycorrhizal roots on studied site. Consequently total values of Species richness index and Shannon-Weaver diversity index were 0.80 and 0.43, respectively. No structures of arbuscular mycorrhizal fungi were recorded. Unfavourable environmental conditions prevailing on investigated site caused decrease of ectomycorrhizal types diversity. Our findings point out that mycorrhyzal fungal community could be used as an appropriate indicator of environmental changes.

  5. Mycorrhizal effects on nutrient cycling, nutrient leaching and N2O production in experimental grassland

    NARCIS (Netherlands)

    Bender, S.F.; Conen, F.; van der Heijden, M.G.A.

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) can enhance plant nutrition and growth. However, their contribution to nutrient cycling in ecosystems is still poorly understood. Using experimental grassland microcosms filled with two different soil types (pasture and heath soil) and fertilized with different N

  6. Shifts in mycorrhizal fungi during the evolution of autotrophy to mycoheterotrophy in Cymbidium (Orchidaceae).

    Science.gov (United States)

    Ogura-Tsujita, Yuki; Yokoyama, Jun; Miyoshi, Kazumitsu; Yukawa, Tomohisa

    2012-07-01

    Mycoheterotrophic plants, which completely depend upon mycorrhizal fungi for their nutrient supply, have unusual associations with fungal partners. The processes involved in shifts in fungal associations during cladogenesis of plant partners from autotrophy to mycoheterotrophy have not been demonstrated using a robust phylogenetic framework. Consequences of a mycorrhizal shift were examined in Cymbidium (Orchidaceae) using achlorophyllous and sister chlorophyllous species. Fungal associates of the two achlorophyllous mycoheterotrophs (C. macrorhizon and C. aberrans), their close relatives, the chlorophyllous mixotrophs (C. goeringii and C. lancifolium) and an outgroup, the chlorophyllous autotroph C. dayanum, were identified by internal transcribed spacers of the nuclear ribosomal DNA sequences. Molecular identification of mycorrhizal fungi revealed: (1) the outgroup autotroph is predominantly dependent on saprobic Tulasnellaceae, (2) the mixotrophs associate with the Tulasnellaceae and ectomycorrhizal groups including the Sebacinales, Russulaceae, Thelephoraceae and Clavulinaceae, and (3) the two mycoheterotrophs are mostly specialized with ectomycorrhizal Sebacinales. Fungal partners in Cymbidium have shifted from saprobic to ectomycorrhizal fungi via a phase of coexistence of both nutritional types of fungi. These three phases correspond to the evolution from autotrophy to mycoheterotrophy via mixotrophy in Cymbidium. We demonstrate that shifts in mycorrhizal fungi correlate with the evolution of nutritional modes in plants. Furthermore, gradual shifts in fungal partners through a phase of coexistence of different types of mycobionts may play a crucial role in the evolution of mycoheterotrophic plants.

  7. pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita.

    Science.gov (United States)

    Funamoto, Rintaro; Saito, Katsuharu; Oyaizu, Hiroshi; Aono, Toshihiro; Saito, Masanori

    2015-01-01

    Arbuscular mycorrhizal fungi play an important role in phosphate supply to the host plants. The fungal hyphae contain tubular vacuoles where phosphate compounds such as polyphosphate are accumulated. Despite their importance for the phosphate storage, little is known about the physiological properties of the tubular vacuoles in arbuscular mycorrhizal fungi. As an indicator of the physiological state in vacuoles, we measured pH of tubular vacuoles in living hyphae of arbuscular mycorrhizal fungus Gigaspora margarita using ratio image analysis with pH-dependent fluorescent probe, 6-carboxyfluorescein. Fluorescent images of the fine tubular vacuoles were obtained using a laser scanning confocal microscope, which enabled calculation of vacuolar pH with high spatial resolution. The tubular vacuoles showed mean pH of 5.6 and a pH range of 5.1-6.3. These results suggest that the tubular vacuoles of arbuscular mycorrhizal fungi have a mildly acidic pH just like vacuoles of other fungal species including yeast and ectomycorrhizal fungi.

  8. Nonlegumes, legumes, and root nodules harbor different arbuscular mycorrhizal fungal communities.

    NARCIS (Netherlands)

    Scheublin, T.R.; Ridgway, K.P.; Young, J.P.W.; van der Heijden, M.G.A.

    2004-01-01

    Legumes are an important plant functional group since they can form a tripartite symbiosis with nitrogen-fixing Rhizobium bacteria and phosphorus-acquiring arbuscular mycorrhizal fungi (AMF). However, not much is known about AMF community composition in legumes and their root nodules. In this study,

  9. Mycorrhizal Associations and Trophic Modes in Coexisting Orchids: An Ecological Continuum between Auto- and Mixotrophy.

    Science.gov (United States)

    Jacquemyn, Hans; Waud, Michael; Brys, Rein; Lallemand, Félix; Courty, Pierre-Emmanuel; Robionek, Alicja; Selosse, Marc-André

    2017-01-01

    Two distinct nutritional syndromes have been described in temperate green orchids. Most orchids form mycorrhizas with rhizoctonia fungi and are considered autotrophic. Some orchids, however, associate with fungi that simultaneously form ectomycorrhizas with surrounding trees and derive their carbon from these fungi. This evolutionarily derived condition has been called mixotrophy or partial mycoheterotrophy and is characterized by 13 C enrichment and high N content. Although it has been suggested that the two major nutritional syndromes are clearly distinct and tightly linked to the composition of mycorrhizal communities, recent studies have challenged this assumption. Here, we investigated whether mycorrhizal communities and nutritional syndromes differed between seven green orchid species that co-occur under similar ecological conditions (coastal dune slacks). Our results showed that mycorrhizal communities differed significantly between orchid species. Rhizoctonia fungi dominated in Dactylorhiza sp., Herminium monorchis , and Epipactis palustris , which were autotrophic based on 13 C and N content. Conversely, Liparis loeselii and Epipactis neerlandica associated primarily with ectomycorrhizal fungi but surprisingly, 13 C and N content supported mixotrophy only in E. neerlandica . This, together with the finding of some ectomycorrhizal fungi in rhizoctonia-associated orchids, suggests that there exists an ecological continuum between the two syndromes. The presence of a large number of indicator species associating with individual orchid species further confirms previous findings that mycorrhizal fungi may be important factors driving niche-partitioning in terrestrial orchids and therefore contribute to orchid coexistence.

  10. Presence and identity of arbuscular mycorrhizal fungi influence competitive interactions between plant species.

    NARCIS (Netherlands)

    Scheublin, T.R.; van Logtestijn, R.S.P; van der Heijden, M.G.A.

    2007-01-01

    1 Competition for nutrients is an important factor structuring plant communities. Plant symbionts such as arbuscular mycorrhizal fungi (AMF) can have considerable influence on nutrient uptake and are therefore likely to influence plant competition. In this study we investigated the influence of

  11. Simulated nitrogen deposition affects community structure of arbuscular mycorrhizal fungi in northern hardwood forests

    Science.gov (United States)

    Linda T.A. Van Diepen; Erik Lilleskov; Kurt S. Pregitzer

    2011-01-01

    Our previous investigation found elevated nitrogen deposition caused declines in abundance of arbuscular mycorrhizal fungi (AMF) associated with forest trees, but little is known about how nitrogen affects the AMF community composition and structure within forest ecosystems. We hypothesized that N deposition would lead to significant changes in the AMF community...

  12. Plant hormones in arbuscular mycorrhizal symbioses: an emerging role for gibberellins.

    Science.gov (United States)

    Foo, Eloise; Ross, John J; Jones, William T; Reid, James B

    2013-05-01

    Arbuscular mycorrhizal symbioses are important for nutrient acquisition in >80 % of terrestrial plants. Recently there have been major breakthroughs in understanding the signals that regulate colonization by the fungus, but the roles of the known plant hormones are still emerging. Here our understanding of the roles of abscisic acid, ethylene, auxin, strigolactones, salicylic acid and jasmonic acid is discussed, and the roles of gibberellins and brassinosteroids examined. Pea mutants deficient in gibberellins, DELLA proteins and brassinosteroids are used to determine whether fungal colonization is altered by the level of these hormones or signalling compounds. Expression of genes activated during mycorrhizal colonization is also monitored. Arbuscular mycorrhizal colonization of pea roots is substantially increased in gibberellin-deficient na-1 mutants compared with wild-type plants. This is reversed by application of GA3. Mutant la cry-s, which lacks gibberellin signalling DELLA proteins, shows reduced colonization. These changes were parallelled by changes in the expression of genes associated with mycorrhizal colonization. The brassinosteroid-deficient lkb mutant showed no change in colonization. Biologically active gibberellins suppress arbuscule formation in pea roots, and DELLA proteins are essential for this response, indicating that this role occurs within the root cells.

  13. Taxon-specific PCR primers to detect two inconspicuous arbuscular mycorrhizal fungi from temperate agricultural grassland

    NARCIS (Netherlands)

    Gamper, H.A.; Leuchtmann, A.

    2007-01-01

    Taxon-specific polymerase chain reaction (PCR) primers enable detection of arbuscular mycorrhizal fungi (AMF, Glomeromycota) in plant roots where the fungi lack discriminative morphological and biochemical characters. We designed and validated pairs of new PCR primers targeted to the flanking

  14. Arbuscular mycorrhizal impacts on competitive interactions between Acacia etbaica and Boswellia papyrifera seedlings under drought stress

    NARCIS (Netherlands)

    Birhane, E.; Sterck, F.J.; Bongers, F.; Kuyper, T.W.

    2014-01-01

    Aims Arbuscular mycorrhizal fungi can have a substantial effect on the water and nutrient uptake by plants and the competition between plants in harsh environments where resource availability comes in pulses. In this study we focus on interspecific competition between Acaia etbaica and Boswellia

  15. Metabolic activity of Glomus intraradices in Arum- and Paris-type arbuscular mycorrhizal colonization

    NARCIS (Netherlands)

    van Aarle, IM; Cavagnaro, TR; Smith, SE; Dickson, S

    Colonization of two plant species by Glomus intraradices was studied to investigate the two morphological types (Arum and Paris), their symbiotic interfaces and metabolic activities. Root pieces and sections were stained to observe the colonization and metabolic activity of all mycorrhizal

  16. Large-scale diversity patterns in spore communities of Arbuscular mycorrhizal fungi [Chapter 2

    Science.gov (United States)

    Javier Alvarez-Sanchez; Nancy C. Johnson; Anita Antoninka; V. Bala Chaudhary; Matthew K. Lau; Suzanne M. Owen; Patricia Gauadarrama; Silvia. Castillo

    2010-01-01

    Surprising little is known about the factors controlling Arbuscular Mycorrhizal (AM) fungal diversity and distribution patterns. A better understanding of these factors is necessary before mycorrhizas can be effectively managed for their benefits in ecosystem restoration and agriculture. The goal of this chapter is to examine the relationships between AM fungal...

  17. Arbuscular mycorrhizal fungi and dark septate fungi in plants associated with aquatic environments

    Directory of Open Access Journals (Sweden)

    Josy Fraccaro de Marins

    Full Text Available ABSTRACT There have been several reports of symbionts in the roots of plants that live in aquatic environments. Arbuscular mycorrhizal fungi (AMF are the most common microsymbionts and possibly recolonized the aquatic environment together with plants; however, their functions and the extent of their benefits are unclear. Furthermore, the presence of other groups of fungi, such as dark septate fungi (DSF, with functions supposedly analogous to those of mycorrhizal fungi, has also been reported. The present work provides a compilation of data regarding the presence of arbuscular mycorrhizae in plants from, or under the influence of, aquatic environments, and co-colonization by AMF and DSF. Forty species of non-vascular plants, ferns, fern allies, and gymnosperms from 15 families, and 659 species of angiosperms from 87 families were investigated. From the first group (non-flowering plants 57 % of the species showed arbuscular mycorrhizal structures in their tissues or roots, whereas among the second group (flowering plants 71% had such structures. Among the mycorrhizal angiosperms, 52 % showed arbuscules in their roots. DSF were found in 1% of non-flowering plants and 5 % of angiosperms. All of these are discussed in this review.

  18. Resistance to Fusarium basal rot and response to arbuscular mycorrhizal fungi in Allium

    NARCIS (Netherlands)

    Galvan Vivero, G.A.

    2009-01-01

    Onion (Allium cepa L.) cultivation in low input and organic farming systems is hampered by Fusarium basal rot (FBR) and the limited ability of onion to take up nutrients like phosphorus. The symbiosis with arbuscular mycorrhizal fungi (AMF) contributes to plant acquisition of phosphorus, among other

  19. The symbiosis with arbuscular mycorrhizal fungi contributes to plant tolerance to serpentine edaphic stress

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Suda, Jan; Sudová, Radka

    2012-01-01

    Roč. 4, č. 1 (2012), s. 56-64 ISSN 0038-0717 R&D Projects: GA AV ČR KJB600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : serpentine syndrome * arbuscular mycorrhizal fungi * reciprocal transplant experiment Subject RIV: EF - Botanics Impact factor: 3.654, year: 2012

  20. Cultivation of flax in spoil-bank clay: Mycorrhizal inoculation vs. high organic amendments

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Rydlová, Jana; Sudová, Radka; Gryndler, Milan

    2008-01-01

    Roč. 171, č. 6 (2008), s. 872-877 ISSN 1436-8730 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50200510 Keywords : arbuscular mycorrhizal fungi * compost * flax Subject RIV: EF - Botanics Impact factor: 1.284, year: 2008

  1. Mycorrhizal hyphae as ecological niche for highly specialized hypersymbionts – or just soil free-riders?

    Directory of Open Access Journals (Sweden)

    Jan eJansa

    2013-05-01

    Full Text Available Mycorrhizal fungi interconnect two different kinds of environments, namely the plant roots with the surrounding soil. This widespread coexistence of plants and fungi has important consequences for plant mineral nutrition, water acquisition, carbon allocation, tolerance to abiotic and biotic stresses and interplant competition. Yet some current research indicates a number of important roles to be played by hyphae-associated microbes, in addition to the hyphae themselves, in foraging for and acquisition of soil resources and in transformation of organic carbon in the soil-plant systems. We critically review the available scientific evidence for the theory that the surface of mycorrhizal hyphae in soil is colonized by highly specialized microbial communities, and that these fulfill important functions in the ecology of mycorrhizal fungal hyphae such as accessing recalcitrant forms of mineral nutrients, and production of signaling and other compounds in the vicinity of the hyphae. The validity of another hypothesis will then be addressed, namely that the specific associative microbes are rewarded with exclusive access to fungal carbon, which would qualify them as hypersymbionts (i.e. symbionts of symbiotic mycorrhizal fungi. Thereafter, we ask whether recruitment of functionally different microbial assemblages by the hyphae is required under different soil conditions (questioning what evidence is available for such an effect, and we identify knowledge gaps requiring further attention.

  2. Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil. II. Alleviation of drought stress

    NARCIS (Netherlands)

    Quilambo, OA; Weissenhorn, I.; Doddema, H; Kuiper, PJC; Stulen, I.

    2005-01-01

    The effect of drought stress and inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on root colonization and plant growth and yield was studied in two peanut (Arachis hypogaea L.) cultivars-a traditional, low-yielding Mozambican landrace (Local) and a

  3. arbuscular mycorrhizal fungi status of some crops in the cross river ...

    African Journals Online (AJOL)

    PROF EKWUEME

    KEYWORDS: AMF, Colonization, Spore density, Foliar nutrients, Cross River Basin of Nigeria. INTRODUCTION. Arbuscular mycorrhizal fungi (AMF) are found in most agricultural soils (Ryan and Angus, 2003). They are broad-host ranged and colonize the roots of most crops and weeds. About 90% of terrestrial plants.

  4. Decline of arbuscular mycorrhizal fungi in northern hardwood forests exposed to chronic nitrogen additions

    Science.gov (United States)

    Linda T.A. van Diepen; Erik A. Lilleskov; Kurt S. Pregitzer; R. Michael Miller

    2007-01-01

    Arbuscular mycorrhizal (AM) fungi are important below-ground carbon (C) sinks that can be sensitive to increased nitrogen (N) availability. The abundance of AM fungi (AMF) was estimated in maple (Acer spp.) fine roots following more than a decade of experimental additions of N designed to simulate chronic atmospheric N deposition.

  5. Impact of conservation tillage and organic farming on the diversity ofarbuscular mycorrhizal fungi

    NARCIS (Netherlands)

    Säle, Verena; Aguilera, Paula; Laczko, Endre; Mäder, Paul; Berner, Alfred; Zihlmann, Urs; van der Heijden, Marcel G A|info:eu-repo/dai/nl/240923901; Oehl, Fritz

    2015-01-01

    Communities of arbuscular mycorrhizal fungi (AMF) are strongly affected by land use intensity and soil type. The impact of tillage practices on AMF communities is still poorly understood, especially in organic farming systems. Our objective was to investigate the impact of soil cultivation on AMF

  6. Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil.

    Science.gov (United States)

    Ambrosini, Vítor Gabriel; Voges, Joana Gerent; Canton, Ludiana; Couto, Rafael da Rosa; Ferreira, Paulo Ademar Avelar; Comin, Jucinei José; de Melo, George Wellington Bastos; Brunetto, Gustavo; Soares, Cláudio Roberto Fonsêca Sousa

    2015-01-01

    High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis) and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM), height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels.

  7. Physiology of mycelial growth of the mycorrhizal mushroom Cantharellus cibarius Fr.

    NARCIS (Netherlands)

    Straatsma, G.

    1986-01-01

    In this thesis in vitro growth of mycelium of Cantharellus cibarius Fr. is described as the first step in the domestication of this edible mycorrhizal mushroom. A collection of pure cultures was obtained and the requirements for vegetative growth were

  8. Exogenous Polyamines Improve Mycorrhizal Development And Growth And Flowering Of Freesia hybrida

    Directory of Open Access Journals (Sweden)

    Rezvanypour Shirin

    2015-12-01

    Full Text Available An experiment was conducted in order to investigate the effects of exogenous polyamines (PAs on the development of mycorrhizae in roots, nutrient uptake and vegetative and reproductive growth of Freesia hybrida ‘Golden Wave’. Corms of freesia were inoculated with Rhizophagus intraradices at sowing time and treated once a week by one of three PAs, putrescine (Put, spermidine or spermine, in concentrations of 0.05 and 0.1 mM each as foliar application or soil drench. Application of PAs, especially as soil drench, increased mycorrhizal colonization as well as the growth and development of inoculated plants. Among the three PAs, Put in 0.1 mM concentration was the most effective in increasing colonization, enhancing floral stem length and diameter, floral spike length, floret number on main and lateral spikes and increasing corm and cormlet weight, corm diameter and cormlet number. Sole application of arbuscular mycorrhizal fungi had no significant effect on the flowering time but soil drench with 0.1 mM Put accelerated flowering by about 17 days. Application of PAs elevated leaves N, P, K, Mg, Fe and Zn and corms’ P, K, Ca, Fe and Zn concentration of inoculated plants. Our results suggest that soil drench application of PAs, especially Put, positively influenced mycorrhizal inoculation and nutrient uptake, which leads to improving growth, flower and corm production and quality of mycorrhizal plants of freesia.

  9. Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil

    Directory of Open Access Journals (Sweden)

    Vítor Gabriel Ambrosini

    2015-12-01

    Full Text Available Abstract High copper (Cu levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF. The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM, height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels.

  10. Glomus eburneum and Scutellospora fulgida, species of arbuscular mycorrhizal fungi (Glomeromycota new for Europe

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2013-12-01

    Full Text Available Morphological characters of spores and mycorrhizae of Glomus eburneum and spores of Scutellospora fulgida, arbuscular mycorrhizal fungi of the phylum Glomeromycota, are described and illustrated. Additionally, the known distribution of these species in both Poland and other regions of the world is presented. Both species were not earlier reported from Europe.

  11. Predicting plant responses to mycorrhizal: integrating evolutionary history and plant traits

    Science.gov (United States)

    The importance of mycorrhizae to most individual plant species is unknown, and responses to mycorrhizal fungi are known to vary among plant species. This complicates interpreting the extent that mycorrhizae affect plant populations, communities, and ecosystems and contributes to their underutilizat...

  12. Activation of Symbiosis Signaling by Arbuscular Mycorrhizal Fungi in Legumes and Rice[OPEN

    Science.gov (United States)

    Sun, Jongho; Miller, J. Benjamin; Granqvist, Emma; Wiley-Kalil, Audrey; Gobbato, Enrico; Maillet, Fabienne; Cottaz, Sylvain; Samain, Eric; Venkateshwaran, Muthusubramanian; Fort, Sébastien; Morris, Richard J.; Ané, Jean-Michel; Dénarié, Jean; Oldroyd, Giles E.D.

    2015-01-01

    Establishment of arbuscular mycorrhizal interactions involves plant recognition of diffusible signals from the fungus, including lipochitooligosaccharides (LCOs) and chitooligosaccharides (COs). Nitrogen-fixing rhizobial bacteria that associate with leguminous plants also signal to their hosts via LCOs, the so-called Nod factors. Here, we have assessed the induction of symbiotic signaling by the arbuscular mycorrhizal (Myc) fungal-produced LCOs and COs in legumes and rice (Oryza sativa). We show that Myc-LCOs and tetra-acetyl chitotetraose (CO4) activate the common symbiosis signaling pathway, with resultant calcium oscillations in root epidermal cells of Medicago truncatula and Lotus japonicus. The nature of the calcium oscillations is similar for LCOs produced by rhizobial bacteria and by mycorrhizal fungi; however, Myc-LCOs activate distinct gene expression. Calcium oscillations were activated in rice atrichoblasts by CO4, but not the Myc-LCOs, whereas a mix of CO4 and Myc-LCOs activated calcium oscillations in rice trichoblasts. In contrast, stimulation of lateral root emergence occurred following treatment with Myc-LCOs, but not CO4, in M. truncatula, whereas both Myc-LCOs and CO4 were active in rice. Our work indicates that legumes and non-legumes differ in their perception of Myc-LCO and CO signals, suggesting that different plant species respond to different components in the mix of signals produced by arbuscular mycorrhizal fungi. PMID:25724637

  13. Production of native arbuscular mycorrhizal fungi inoculum under different environmental conditions

    Directory of Open Access Journals (Sweden)

    Yamir Torres-Arias

    Full Text Available Abstract In order to obtain an arbuscular mycorrhizal fungi (AMF native inoculum from Sierra de Moa and determine the most appropriate conditions for its big scale production, four light and temperature combinations were tested in three plant species (Calophyllum antillanum, Talipariti elatum and Paspalum notatum. Growth and development parameters, as well as the mycorrhizal functioning of the seedlings were evaluated. The natural light treatment under high temperatures (L-H was the most suitable for the growth and development of the three plant species, showing the highest total biomass values, mainly of root, and a positive root-shoot ratio balance. This treatment also promoted higher values of root mycorrhizal colonization, external mycelium and AMF spore density. A total of 38 AMF species were identified among the plants and environmental conditions tested. Archaeospora sp.1, Glomus sp.5, Glomus brohultii and G. glomerulatum were observed in all the treatments. The L-H condition can be recommended for native inoculum production, as it promotes a better expression of the AM symbiosis and an elevated production of mycorrhizal propagules.

  14. Mutualism Persistence and Abandonment during the Evolution of the Mycorrhizal Symbiosis.

    Science.gov (United States)

    Maherali, Hafiz; Oberle, Brad; Stevens, Peter F; Cornwell, William K; McGlinn, Daniel J

    2016-11-01

    Mutualistic symbioses with mycorrhizal fungi are widespread in plants. The majority of plant species associate with arbuscular mycorrhizal (AM) fungi. By contrast, the minority associate with ectomycorrhizal (EM) fungi, have abandoned the symbiosis and are nonmycorrhizal (NM), or engage in an intermediate, weakly AM symbiosis (AMNM). To understand the processes that maintain the mycorrhizal symbiosis or cause its loss, we reconstructed its evolution using a ∼3,000-species seed plant phylogeny integrated with mycorrhizal state information. Reconstruction indicated that the common ancestor of seed plants most likely associated with AM fungi and that the EM, NM, and AMNM states descended from the AM state. Direct transitions from the AM state to the EM and NM states were infrequent and generally irreversible, implying that natural selection or genetic constraint could promote stasis once a particular state evolved. However, the evolution of the NM state was more frequent via an indirect pathway through the AMNM state, suggesting that weakening of the AM symbiosis is a necessary precursor to mutualism abandonment. Nevertheless, reversions from the AMNM state back to the AM state were an order of magnitude more likely than transitions to the NM state, suggesting that natural selection favors the AM symbiosis over mutualism abandonment.

  15. Carbon availability for the fungus triggers nitrogen uptake and transport in the arbuscular mycorrhizal symbiosis

    Science.gov (United States)

    The arbuscular mycorrhizal (AM) symbiosis is characterized by a transfer of nutrients in exchange for carbon. We tested the effect of the carbon availability for the AM fungus Glomus intraradices on nitrogen (N) uptake and transport in the symbiosis. We followed the uptake and transport of 15N and ...

  16. Activation of symbiosis signaling by arbuscular mycorrhizal fungi in legumes and rice.

    Science.gov (United States)

    Sun, Jongho; Miller, J Benjamin; Granqvist, Emma; Wiley-Kalil, Audrey; Gobbato, Enrico; Maillet, Fabienne; Cottaz, Sylvain; Samain, Eric; Venkateshwaran, Muthusubramanian; Fort, Sébastien; Morris, Richard J; Ané, Jean-Michel; Dénarié, Jean; Oldroyd, Giles E D

    2015-03-01

    Establishment of arbuscular mycorrhizal interactions involves plant recognition of diffusible signals from the fungus, including lipochitooligosaccharides (LCOs) and chitooligosaccharides (COs). Nitrogen-fixing rhizobial bacteria that associate with leguminous plants also signal to their hosts via LCOs, the so-called Nod factors. Here, we have assessed the induction of symbiotic signaling by the arbuscular mycorrhizal (Myc) fungal-produced LCOs and COs in legumes and rice (Oryza sativa). We show that Myc-LCOs and tetra-acetyl chitotetraose (CO4) activate the common symbiosis signaling pathway, with resultant calcium oscillations in root epidermal cells of Medicago truncatula and Lotus japonicus. The nature of the calcium oscillations is similar for LCOs produced by rhizobial bacteria and by mycorrhizal fungi; however, Myc-LCOs activate distinct gene expression. Calcium oscillations were activated in rice atrichoblasts by CO4, but not the Myc-LCOs, whereas a mix of CO4 and Myc-LCOs activated calcium oscillations in rice trichoblasts. In contrast, stimulation of lateral root emergence occurred following treatment with Myc-LCOs, but not CO4, in M. truncatula, whereas both Myc-LCOs and CO4 were active in rice. Our work indicates that legumes and non-legumes differ in their perception of Myc-LCO and CO signals, suggesting that different plant species respond to different components in the mix of signals produced by arbuscular mycorrhizal fungi. © 2015 American Society of Plant Biologists. All rights reserved.

  17. Mycorrhizal compatibility and symbiotic reproduction of Gavilea australis, an endangered terrestrial orchid from south Patagonia.

    Science.gov (United States)

    Fracchia, Sebastián; Aranda-Rickert, Adriana; Flachsland, Eduardo; Terada, Graciela; Sede, Silvana

    2014-11-01

    Gavilea australis is a terrestrial orchid endemic from insular south Argentina and Chile. Meeting aspects of mycorrhizal fungi identity and compatibility in this orchid species is essential for propagation and conservation purposes. These knowledge represent also a first approach to elucidate the mycorrhizal specificity of this species. In order to evaluate both the mycorrhizal compatibility and the symbiotic seed germination of G. australis, we isolated and identified its root endophytic fungal strains as well as those from two sympatric species: Gavilea lutea and Codonorchis lessonii. In addition, we tested two other strains isolated from allopatric terrestrial orchid species from central Argentina. All fungal strains formed coilings and pelotons inside protocorms and promoted, at varying degrees, seed germination, and protocorm development until seedlings had two to three leaves. These results suggest a low mycorrhizal specificity of G. australis and contribute to a better knowledge of the biology of this orchid as well as of other sympatric Patagonian orchid species, all of them currently under serious risk of extinction.

  18. Age-dependent mycorrhizal specificity in an invasive orchid, Oeceoclades maculata.

    Science.gov (United States)

    Bayman, Paul; Mosquera-Espinosa, Ana T; Saladini-Aponte, Carla M; Hurtado-Guevara, Nilbeth C; Viera-Ruiz, Naida L

    2016-11-01

    Oeceoclades maculata is a naturalized, invasive, terrestrial orchid in Puerto Rico and elsewhere in the neotropics. We asked whether its success might be partly explained by its mycorrhizal associations, hypothesizing a relationship with many fungal partners or with one widely distributed partner. Oeceoclades maculata roots were collected throughout Puerto Rico, and the degree of mycorrhizal colonization was measured. For identification of fungi, the ITS region was sequenced from pure cultures and directly from roots. Representative fungi were used for symbiotic seed germination experiments. Colonization of O. maculata roots was very variable. The most common fungus identified by BLAST searches was Psathyrella cf. candolleana, but typical orchid mycorrhizal fungi (Ceratobasidium and Tulasnella) were also found, as were a range of saprotrophs. Seeds germinated in vitro only in the presence of Psathyrella. These results are surprising in two respects. First, O. maculata appears to be highly specific for fungi during seed germination, but unusually promiscuous as adult plants. Second, mycorrhizal associations with Psathyrella and with other saprotrophic fungi have been previously reported, but only from mycoheterotrophic (i.e., nonphotosynthetic) orchids, not from green orchids like Oeceoclades. This combination may partly explain the success of Oeceoclades. © 2016 Botanical Society of America.

  19. Mycorrhizal Associations and Trophic Modes in Coexisting Orchids: An Ecological Continuum between Auto- and Mixotrophy

    Directory of Open Access Journals (Sweden)

    Hans Jacquemyn

    2017-08-01

    Full Text Available Two distinct nutritional syndromes have been described in temperate green orchids. Most orchids form mycorrhizas with rhizoctonia fungi and are considered autotrophic. Some orchids, however, associate with fungi that simultaneously form ectomycorrhizas with surrounding trees and derive their carbon from these fungi. This evolutionarily derived condition has been called mixotrophy or partial mycoheterotrophy and is characterized by 13C enrichment and high N content. Although it has been suggested that the two major nutritional syndromes are clearly distinct and tightly linked to the composition of mycorrhizal communities, recent studies have challenged this assumption. Here, we investigated whether mycorrhizal communities and nutritional syndromes differed between seven green orchid species that co-occur under similar ecological conditions (coastal dune slacks. Our results showed that mycorrhizal communities differed significantly between orchid species. Rhizoctonia fungi dominated in Dactylorhiza sp., Herminium monorchis, and Epipactis palustris, which were autotrophic based on 13C and N content. Conversely, Liparis loeselii and Epipactis neerlandica associated primarily with ectomycorrhizal fungi but surprisingly, 13C and N content supported mixotrophy only in E. neerlandica. This, together with the finding of some ectomycorrhizal fungi in rhizoctonia-associated orchids, suggests that there exists an ecological continuum between the two syndromes. The presence of a large number of indicator species associating with individual orchid species further confirms previous findings that mycorrhizal fungi may be important factors driving niche-partitioning in terrestrial orchids and therefore contribute to orchid coexistence.

  20. Mycorrhizal Associations and Trophic Modes in Coexisting Orchids: An Ecological Continuum between Auto- and Mixotrophy

    Science.gov (United States)

    Jacquemyn, Hans; Waud, Michael; Brys, Rein; Lallemand, Félix; Courty, Pierre-Emmanuel; Robionek, Alicja; Selosse, Marc-André

    2017-01-01

    Two distinct nutritional syndromes have been described in temperate green orchids. Most orchids form mycorrhizas with rhizoctonia fungi and are considered autotrophic. Some orchids, however, associate with fungi that simultaneously form ectomycorrhizas with surrounding trees and derive their carbon from these fungi. This evolutionarily derived condition has been called mixotrophy or partial mycoheterotrophy and is characterized by 13C enrichment and high N content. Although it has been suggested that the two major nutritional syndromes are clearly distinct and tightly linked to the composition of mycorrhizal communities, recent studies have challenged this assumption. Here, we investigated whether mycorrhizal communities and nutritional syndromes differed between seven green orchid species that co-occur under similar ecological conditions (coastal dune slacks). Our results showed that mycorrhizal communities differed significantly between orchid species. Rhizoctonia fungi dominated in Dactylorhiza sp., Herminium monorchis, and Epipactis palustris, which were autotrophic based on 13C and N content. Conversely, Liparis loeselii and Epipactis neerlandica associated primarily with ectomycorrhizal fungi but surprisingly, 13C and N content supported mixotrophy only in E. neerlandica. This, together with the finding of some ectomycorrhizal fungi in rhizoctonia-associated orchids, suggests that there exists an ecological continuum between the two syndromes. The presence of a large number of indicator species associating with individual orchid species further confirms previous findings that mycorrhizal fungi may be important factors driving niche-partitioning in terrestrial orchids and therefore contribute to orchid coexistence. PMID:28912791

  1. Context-dependency of arbuscular mycorrhizal fungi on plant-insect interactions in an agroecosystem.

    NARCIS (Netherlands)

    Barber, N.A.; Kiers, E.T.; Hazzard, R.V.; Adler, L.S.

    2013-01-01

    Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF) are generally considered plant mutualists because of their generally positive effects on plant nutrient status and

  2. Arbuscular mycorrhizal associations in Boswellia papyrifera (frankincense-tree) dominated dry deciduous woodlands of Northern Ethiopia.

    NARCIS (Netherlands)

    Emiru Birhane, E.B.; Kuyper, T.W.; Sterck, F.J.; Bongers, F.

    2010-01-01

    This study assessed the arbuscular mycorrhizal (AM) status of Boswellia papyrifera (frankincense-tree) dominated dry deciduous woodlands in relation to season, management and soil depth in Ethiopia. We studied 43 woody species in 52 plots in three areas. All woody species were colonized by AM fungi,

  3. Effect of arbuscular mycorrhizal fungi (AMF) on heavy metal tolerance of alfalfa (Medicago sativa L.) and oat (Avena sativa L.) on a sewage-sludge treated soil; Bedeutung der arbuskulaeren Mykorrhiza (AM) fuer die Schwermetalltoleranz von Luzerne (Medicago sativa L.) und Hafer (Avena sativa L.) auf einem klaerschlammgeduengten Boden

    Energy Technology Data Exchange (ETDEWEB)

    Ricken, B. [Institut fuer Pflanzenernaehrung, Giessen Univ. (Germany); Hoefner, W. [Institut fuer Pflanzenernaehrung, Giessen Univ. (Germany)

    1996-10-01

    In pot experiments with a sewage sludge treated soil, the influence of two arbuscular mycorrhizal fungi (AMF) isolates of Glomus sp. (T6 and D13) on plant growth and on the uptake of heavy metals by alfalfa (Medicago sativa L.) and oat (Avena sativa L.) was investigated. Alfalfa showed an increase of biomass with mycorrhizal infection only to a small extent. In oat AMF inoculation increased the growth of both root and shoot by up to 70% and 55% respectively. Mycorrhization raised the P-content and -uptake in alfalfa, but not in oat, in both roots and shoots. Mycorrhizal alfalfa showed lower Zn-, Cd- and Ni-contents and uptake in roots and shoots. The root length was significantly decreased in mycorrhizal alfalfa plants (up to 38%). The translocation of heavy metals into the shoot of mycorrhizal alfalfa was slightly increased. Mycorrhizal infection of oat led to higher concentrations of Zn, Cd and Ni in the root but to less Zn in the shoot. The translocation of heavy metals to the oat shoot was clearely decreased by mycorrhizal colonisation. This may be based on the ability of fungal tissues to complex heavy metals at the cell walls, thus excluding metals from the shoot. This conclusion is supported by the enhanced root length (up to 78%) of mycorrhizal oat plants in this experiment. The mycorrhizal infection seemed to protect plants against heavy metal pollution in soils. It was obvious that different host plants reacted in different ways. (orig.) [Deutsch] In Gefaessversuchen mit einem klaerschlammgeduengten Boden wurde der Einfluss der arbuskulaeren Mykorrhiza (AM)-Pilzisolate von Glomus sp. (T6 und D13) auf Pflanzenwachstum und Schwermetall (SM)-aufnahme von Luzerne (Medicago sativa L.) und Hafer (Avena sativa L.) untersucht. Das Wachstum von Luzerne wurde durch eine Mykorrhizierung nicht signifikant beeinflusst. Bei Hafer foerderte eine AM-Inokulation mit T6 das Wachstum von Wurzel und Spross bis zu 70% bzw. 55%, zur Reife aber ergab sich gleicher Sprossertrag

  4. Gibberellins Interfere with Symbiosis Signaling and Gene Expression and Alter Colonization by Arbuscular Mycorrhizal Fungi in Lotus japonicus1

    Science.gov (United States)

    Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

    2015-01-01

    Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. PMID:25527715

  5. Gibberellins interfere with symbiosis signaling and gene expression and alter colonization by arbuscular mycorrhizal fungi in Lotus japonicus.

    Science.gov (United States)

    Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

    2015-02-01

    Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. © 2015 American Society of Plant Biologists. All Rights Reserved.

  6. Influence of nitrogen and phosphorus sources on mycorrhizal lettuces under organic farming

    Science.gov (United States)

    Scotti, Riccardo; Seguel, Alex; Cornejo, Pablo; Rao, Maria A.; Borie, Fernando

    2010-05-01

    Arbuscular mycorrhizal fungi (AMF) develop symbiotic associations with plants roots. These associations are very common in the natural environment and can provide a range of benefits to the host plant. AMF improve nutrition, enhance resistance to soil-borne pests and disease, increase resistance to drought and tolerance to heavy metals, and contribute to a better soil structure. However, agricultural intensive managements, such as the use of mineral fertilizes, pesticides, mouldboard tillage, monocultures and use of non-mycorrhizal crops, are detrimental to AMF. As a consequence, agroecosystems are impoverished in AMF and may not provide the full range of benefits to the crop. Organic farming systems may be less unfavourable to AMF because they exclude the use of water-soluble fertilisers and most pesticides, and generally they plan diverse crop rotations. The AMF develop the most common type of symbiosis in nature: about 90% of the plants are mycorrhizal and many agricultural crops are mycorrhizal. One of more mycorrhizal crops is lettuce, that is very widespread in intensive agricultural under greenhouse. Therefore, cultivated lettuce is know to be responsive to mycorrhizal colonization which can reach 80% of root length and contribute to phosphorus and nitrogen absorption by this plant specie. For this work four different lettuce cultivars (Romana, Milanesa, Grande Lagos and Escarola) were used to study mycorrhization under organic agricultural system, supplying compost from agricultural waste (1 kg m-2) as background fertilization for all plots, red guano as phosphorus source (75 U ha-1 and 150 U ha-1 of P2O5), lupine flour as nitrogen source (75 and 150 U/ha of N) and a combination of both. Lettuce plants were cultivated under greenhouse and after two months of growing, plants were harvested and dried and fresh weight of lettuce roots and shoots were evaluated. The number of spores, percentage of colonization, total mycelium and glomalin content were also

  7. Engineering Mycorrhizal Symbioses to Alter Plant Metabolism and Improve Crop Health

    Science.gov (United States)

    French, Katherine E.

    2017-01-01

    Creating sustainable bioeconomies for the 21st century relies on optimizing the use of biological resources to improve agricultural productivity and create new products. Arbuscular mycorrhizae (phylum Glomeromycota) form symbiotic relationships with over 80% of vascular plants. In return for carbon, these fungi improve plant health and tolerance to environmental stress. This symbiosis is over 400 million years old and there are currently over 200 known arbuscular mycorrhizae, with dozens of new species described annually. Metagenomic sequencing of native soil communities, from species-rich meadows to mangroves, suggests biologically diverse habitats support a variety of mycorrhizal species with potential agricultural, medical, and biotechnological applications. This review looks at the effect of mycorrhizae on plant metabolism and how we can harness this symbiosis to improve crop health. I will first describe the mechanisms that underlie this symbiosis and what physiological, metabolic, and environmental factors trigger these plant-fungal relationships. These include mycorrhizal manipulation of host genetic expression, host mitochondrial and plastid proliferation, and increased production of terpenoids and jasmonic acid by the host plant. I will then discuss the effects of mycorrhizae on plant root and foliar secondary metabolism. I subsequently outline how mycorrhizae induce three key benefits in crops: defense against pathogen and herbivore attack, drought resistance, and heavy metal tolerance. I conclude with an overview of current efforts to harness mycorrhizal diversity to improve crop health through customized inoculum. I argue future research should embrace synthetic biology to create mycorrhizal chasses with improved symbiotic abilities and potentially novel functions to improve plant health. As the effects of climate change and anthropogenic disturbance increase, the global diversity of arbuscular mycorrhizal fungi should be monitored and protected to

  8. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    Science.gov (United States)

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

  9. Continent-wide distribution in mycorrhizal fungi: implications for the biogeography of specialized orchids.

    Science.gov (United States)

    Davis, Belinda J; Phillips, Ryan D; Wright, Magali; Linde, Celeste C; Dixon, Kingsley W

    2015-09-01

    Although mycorrhizal associations are predominantly generalist, specialized mycorrhizal interactions have repeatedly evolved in Orchidaceae, suggesting a potential role in limiting the geographical range of orchid species. In particular, the Australian orchid flora is characterized by high mycorrhizal specialization and short-range endemism. This study investigates the mycorrhizae used by Pheladenia deformis, one of the few orchid species to occur across the Australian continent. Specifically, it examines whether P. deformis is widely distributed through using multiple fungi or a single widespread fungus, and if the fungi used by Australian orchids are widespread at the continental scale. Mycorrhizal fungi were isolated from P. deformis populations in eastern and western Australia. Germination trials using seed from western Australian populations were conducted to test if these fungi supported germination, regardless of the region in which they occurred. A phylogenetic analysis was undertaken using isolates from P. deformis and other Australian orchids that use the genus Sebacina to test for the occurrence of operational taxonomic units (OTUs) in eastern and western Australia. With the exception of one isolate, all fungi used by P. deformis belonged to a single fungal OTU of Sebacina. Fungal isolates from eastern and western Australia supported germination of P. deformis. A phylogenetic analysis of Australian Sebacina revealed that all of the OTUs that had been well sampled occurred on both sides of the continent. The use of a widespread fungal OTU in P. deformis enables a broad distribution despite high mycorrhizal specificity. The Sebacina OTUs that are used by a range of Australian orchids occur on both sides of the continent, demonstrating that the short-range endemism prevalent in the orchids is not driven by fungal species with narrow distributions. Alternatively, a combination of specific edaphic requirements and a high incidence of pollination by sexual

  10. Engineering Mycorrhizal Symbioses to Alter Plant Metabolism and Improve Crop Health

    Directory of Open Access Journals (Sweden)

    Katherine E. French

    2017-07-01

    Full Text Available Creating sustainable bioeconomies for the 21st century relies on optimizing the use of biological resources to improve agricultural productivity and create new products. Arbuscular mycorrhizae (phylum Glomeromycota form symbiotic relationships with over 80% of vascular plants. In return for carbon, these fungi improve plant health and tolerance to environmental stress. This symbiosis is over 400 million years old and there are currently over 200 known arbuscular mycorrhizae, with dozens of new species described annually. Metagenomic sequencing of native soil communities, from species-rich meadows to mangroves, suggests biologically diverse habitats support a variety of mycorrhizal species with potential agricultural, medical, and biotechnological applications. This review looks at the effect of mycorrhizae on plant metabolism and how we can harness this symbiosis to improve crop health. I will first describe the mechanisms that underlie this symbiosis and what physiological, metabolic, and environmental factors trigger these plant-fungal relationships. These include mycorrhizal manipulation of host genetic expression, host mitochondrial and plastid proliferation, and increased production of terpenoids and jasmonic acid by the host plant. I will then discuss the effects of mycorrhizae on plant root and foliar secondary metabolism. I subsequently outline how mycorrhizae induce three key benefits in crops: defense against pathogen and herbivore attack, drought resistance, and heavy metal tolerance. I conclude with an overview of current efforts to harness mycorrhizal diversity to improve crop health through customized inoculum. I argue future research should embrace synthetic biology to create mycorrhizal chasses with improved symbiotic abilities and potentially novel functions to improve plant health. As the effects of climate change and anthropogenic disturbance increase, the global diversity of arbuscular mycorrhizal fungi should be monitored

  11. Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants.

    Science.gov (United States)

    Aroca, Ricardo; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; Paz, José Antonio; García-Mina, José María; Pozo, María José; López-Ráez, Juan Antonio

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress. Copyright © 2012 Elsevier GmbH. All rights reserved.

  12. Engineering Mycorrhizal Symbioses to Alter Plant Metabolism and Improve Crop Health.

    Science.gov (United States)

    French, Katherine E

    2017-01-01

    Creating sustainable bioeconomies for the 21st century relies on optimizing the use of biological resources to improve agricultural productivity and create new products. Arbuscular mycorrhizae (phylum Glomeromycota) form symbiotic relationships with over 80% of vascular plants. In return for carbon, these fungi improve plant health and tolerance to environmental stress. This symbiosis is over 400 million years old and there are currently over 200 known arbuscular mycorrhizae, with dozens of new species described annually. Metagenomic sequencing of native soil communities, from species-rich meadows to mangroves, suggests biologically diverse habitats support a variety of mycorrhizal species with potential agricultural, medical, and biotechnological applications. This review looks at the effect of mycorrhizae on plant metabolism and how we can harness this symbiosis to improve crop health. I will first describe the mechanisms that underlie this symbiosis and what physiological, metabolic, and environmental factors trigger these plant-fungal relationships. These include mycorrhizal manipulation of host genetic expression, host mitochondrial and plastid proliferation, and increased production of terpenoids and jasmonic acid by the host plant. I will then discuss the effects of mycorrhizae on plant root and foliar secondary metabolism. I subsequently outline how mycorrhizae induce three key benefits in crops: defense against pathogen and herbivore attack, drought resistance, and heavy metal tolerance. I conclude with an overview of current efforts to harness mycorrhizal diversity to improve crop health through customized inoculum. I argue future research should embrace synthetic biology to create mycorrhizal chasses with improved symbiotic abilities and potentially novel functions to improve plant health. As the effects of climate change and anthropogenic disturbance increase, the global diversity of arbuscular mycorrhizal fungi should be monitored and protected to

  13. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  14. Carbon and nutrients recycling when leaves falling off: mycorrhizal association matters

    Science.gov (United States)

    Zhang, H., II; Lü, X. T.; Hartmann, H.; Han, X.; Trumbore, S.

    2016-12-01

    Root-associated mycorrhizal fungi is being increasingly recognized for their roles in influencing soil carbon (C) storage, plant growth and nutrient cycling, whereas mycorrhizae-mediated C dynamics and nutrient acquisition strategy strongly different. Because of a reinforcing feedback from belowground, how different mycorrhizal plants differ in aboveground nutrient status and recycle from senesced to green leaves remains unknown. Based on a global database of C and nutrients concentrations in plant green and senesced leaves, we further identified plant mycorrhizal types (here focus on arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants) for woody species and tested whether mycorrhizal types showing consistent effects in plant nutrient status and recycle. Generally, nutrient resorptions from senesced to green leaves for ECM plants are more conservative, balanced and sensitive to climate compare to AM plants. Specifically, we first found lower nutrients concentrations in green and senesced leaves whereas greater nutrient resorption efficiency (NuR) for ECM vs. AM plants. However, C concentration in green and senesced leaves were significant greater while NuR was lower for ECM plants. Second, compare to that for AM plants, we found a general balanced N:P resorption ratio ( 1) for ECM plants, indicating ECM plants had greater ability to balance their N and P resorption simultaneously. Third, we found NuR in N, P and K (potassium) for ECM plants were sensitive to the variation of MAT and MAP while these for AM plants showed no clear trend. Our results suggested that accounting for the influence of mycorrhizae on C and nutrient dynamics in vegetation models will be critical for predicting ecosystem responses and feedbacks to climate change.

  15. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved.

    Science.gov (United States)

    Schouteden, Nele; De Waele, Dirk; Panis, Bart; Vos, Christine M

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead.

  16. Determinants of arbuscular mycorrhizal communities - soil properties or land use?

    Science.gov (United States)

    Jansa, J.; Erb, A.; Oberholzer, H.-R.; Šmilauer, P.; Egli, S.

    2012-04-01

    Arbuscular mycorrhizal (AM) fungi accompanied terrestrial plants since some 500 million years of their evolution and are now widespread in all continents and virtually all soils of the world. They establish symbiotic interactions with a majority of extant higher plant species including most economically important plants. They are heavily implicated in plant nutrition, plant-soil carbon cycling, and tolerance to environmental stresses. Under field conditions, AM fungi usually form multispecies communities both in the soils and in plant roots, and it is becoming well established that various human interventions like cropping, crop rotation, tillage, and fertilization may all drive changes in the community composition of these fungi and, consequently, in the symbiotic benefits to the plants. Most of current evidence is stemming from individual short and long-term field trials, and the different studies usually employed diverse approaches, limiting the comparability of results across sites. Large scale sampling designs using unified research methods across different soil types and land use systems have hardly been employed so far. However, this would be imperative to allow direct comparisons of the effects of various environmental conditions (soil type, climate) and human land use practices on the indigenous soil-borne symbiotic microbes in general and the AM fungi in particular. To contribute to filling this gap, we conducted molecular profiling of AM communities in more than 150 Swiss agricultural soils, developed on a range of parent materials, covering a wide range of soil properties such as pH value, texture, carbon content and altitude, and including highly productive fields through alpine pastures. This study indicated strong correlations between AM fungal community patterns and features like soil pH and texture, as well as some consistent shifts in fungal communities due to specific aspects of land use like tillage or fertilization. These results thus appear to

  17. Arbuscular mycorrhizal fungal communities in forest plant roots are simultaneously shaped by host characteristics and canopy-mediated light availability

    NARCIS (Netherlands)

    Koorem, Kadri; Tulva, Ingmar; Davison, John; Jairus, Teele; Öpik, Maarja; Vasar, Martti; Zobel, Martin; Moora, Mari

    2017-01-01

    Background and aims The majority of terrestrial plant species associate with arbuscular mycorrhizal (AM) fungi, to exchange carbon compounds with nutrients. However, the factors that determine the composition of AM fungal communities in individual plant roots remain poorly understood. We

  18. Seed coating with arbuscular mycorrhizal fungi as an ecotechnological approach for sustainable agricultural production of common wheat (Triticum aestivum L.)

    Czech Academy of Sciences Publication Activity Database

    Oliviera, R. S.; Rocha, I.; Ma, Y.; Vosátka, Miroslav; Freitas, H.

    2016-01-01

    Roč. 79, č. 7 (2016), s. 329-337 ISSN 1528-7394 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * phosphorus uptake * soil Subject RIV: GC - Agronomy Impact factor: 2.731, year: 2016

  19. Plant and fungal gene expression in mycorrhizal protocorms of the orchid Serapias vomeracea colonized by Tulasnella calospora.

    Science.gov (United States)

    Balestrini, Raffaella; Nerva, Luca; Sillo, Fabiano; Girlanda, Mariangela; Perotto, Silvia

    2014-01-01

    Little is known on the molecular bases of plant-fungal interactions in orchid mycorrhiza. We developed a model system to investigate gene expression in mycorrhizal protocorms of Serapias vomeracea colonised by Tulasnella calospora. Our recent results with a small panel of genes as indicators of plant response to mycorrhizal colonization indicate that genes related with plant defense were not significantly up-regulated in mycorrhizal tissues. Here, we used laser microdissection to investigate whether expression of some orchid genes was restricted to specific cell types. Results showed that SvNod1, a S. vomeracea nodulin-like protein containing a plastocyanin-like domain, is expressed only in protocorm cells containing intracellular fungal hyphae. In addition, we investigated a family of fungal zinc metallopeptidases (M36). This gene family has expanded in the T. calospora genome and RNA-Seq experiments indicate that some members of the M36 metallopeptidases family are differentially regulated in orchid mycorrhizal protocorms.

  20. Effects of rhizobium, arbuscular mycorrhizal fungi and anion content of simulated rain on subterranean clover.

    Science.gov (United States)

    Shafer, S R; Schoeneberger, M M; Horton, S J; Davey, C B; Miller, J E

    1996-01-01

    An experiment was conducted to determine the extent to which rhizobia, mycorrhizal fungi, and anions in simulated rain affect plant growth response to acid deposition. Germinating subterranean clover seeds were planted in steam-pasteurized soil in pots and inoculated with Rhizobium leguminosarum, Glomus intraradices, Glomus etunicatum, R. leguminosarum + G. intraradices, R. leguminosarum + G. etunicatum, or no microbial symbionts. Beginning 3 weeks later, plants and the soil surface were exposed to simulated rain in a greenhouse on 3 days week(-1) for 12 weeks. Rain solutions were deionized water amended with background ions only (pH 5.0) or also adjusted to pH 3.0 with HNO3 only, H2SO4 only, or a 50/50 mixture of the two acids. Glomus intraradices colonized plant roots poorly, and G. intraradices-inoculated plants responded like nonmycorrhizal plants to rhizobia and rain treatments. Variation in plant biomass attributable to different rain formulations was strongest for G. etunicatum-inoculated plants, and the effect of rain formulation differed with respect to nodulation by rhizobia. The smallest plants at the end of the experiment were noninoculated plants exposed to rains (0.38 g mean dry weight total for 3 plants pot(-1)). Among nonnodulated plants infected by G. etunicatum, those exposed to HNO3 rain were largest, followed by plants exposed to HNO3 + H2SO4, pH 5.0, and H2SO4 rain, in that order. Among plants inoculated with both R. leguminosarum + G. etunicatum, however, the greatest biomass occurred with pH 5.0 rains, resulting in the largest plants in the study (1.00 g/3 plants). Treatment-related variation among root and shoot biomass data reflected those for whole-plant biomass. Based on quantification of biomass and N concentrations in shoot and root tissues, total N content of plants inoculated with G. etunicatum alone and exposed to the HNO3 + H2SO4 rains was approximately the same as plants inoculated with R. leguminosarum + G. entunicatum and exposed

  1. Assessment of mycorrhizal colonisation and soil nutrients in unmanaged fire-impacted soils from two target restoration sites

    Energy Technology Data Exchange (ETDEWEB)

    Dias, J. M.; Oliveira, R. S.; Franco, A. R.; Ritz, K.; Nunan, N.; Castro, P. M. L.

    2010-07-01

    The mycorrhizal colonisation of plants grown in unmanaged soils from two restoration sites with a fire history in Northern Portugal was evaluated from the perspective of supporting restoration programmes. To promote restoration of original tree stands, Quercus ilex L. and Pinus pinaster Ait. were used as target species on two sites, denoted Site 1 and 2 respectively. The aim of the study was to assess whether mycorrhizal propagules that survived fire episodes could serve as in situ inoculum sources, and to analyse the spatial distribution of soil nutrients and mycorrhizal parameters. In a laboratory bioassay, P. pinaster and Q. ilex seedlings were grown on soils from the target sites and root colonisation by ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi was determined. The ECM root colonisation levels found indicated that soil from Site 2 contained sufficient ECM propagules to serve as a primary source of inoculum for P. pinaster. The low levels of ECM and AM colonisation obtained on the roots of plants grown in soil from Site 1 indicated that the existing mycorrhizal propagules might be insufficient for effective root colonisation of Q. ilex. Different ECM morphotypes were found in plants grown in soil from the two sites. At Site 2 mycorrhizal parameters were found to be spatially structured, with significant differences in ECM colonisation and soil P concentrations between regions of either side of an existing watercourse. The spatial distribution of mycorrhizal propagules was related to edaphic parameters (total C and extractable P), and correlations between soil nutrients and mycorrhizal parameters were found. (Author) 31 refs.

  2. Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability

    OpenAIRE

    Zhang, Haoqiang; Liu, Zhenkun; Chen, Hui; Tang, Ming

    2016-01-01

    Robinia pseudoacacia L. (black locust) is a widely planted tree species on Loess Plateau for revegetation. Due to its symbiosis forming capability with arbuscular mycorrhizal (AM) fungi, we explored the influence of arbuscular mycorrhizal fungi on plant biomass, root morphology, root tensile strength and soil aggregate stability in a pot experiment. We inoculated R. pseudoacacia with/without AM fungus (Rhizophagus irregularis or Glomus versiforme), and measured root colonization, plant growth...

  3. Utilization of Biopore Infiltration Hole and Cross Drain Technology to Improve Root Geometry and Mycorrhizal Colonization in Skidding Road

    OpenAIRE

    Diana Prameswari; Supriyanto .; Bambang Hero Saharjo; Basuki Wasis; Prijanto Pamoengkas

    2014-01-01

    Root geometry is important factor in planting in skidding roads. Soil compaction, lack of mycorrhizal population and stunted seedling growth are the common problem in skidding road for reforestation success. Implementation of bio-pore infiltration hole (BIH) and cross drain (CD) technology may improve the skidding road problems. The aim of the study was to examine the use of BIH and CD technology to improve root geometry and mycorrhizal colonization in skidding roads. Shorealeprosula and Sh...

  4. Benefits of the Mycorrhizal Fungi in Tomato Leaves Measured by Open Photoacoustic Cell Technique: Interpretation of the Diffusion Parameters

    Science.gov (United States)

    Sánchez-Rocha, S.; Vargas-Luna, M.; Gutiérrez-Juárez, G.; Huerta-Franco, R.; Olalde-Portugal, V.

    2008-12-01

    The open photoacoustic cell technique was used to measure tomato leaves from plants with and without mycorrhizal fungi ( Glomus fasciculatum). Based on measurement of the photobaric contribution of the photoacoustic signal, the exponential parameter of the diffusion behavior for this contribution was calculated. From this value, the oxygen diffusion coefficient was derived. The changes in the oxygen- diffusion-coefficient-dependent exponential parameter are statistically significant ( p mycorrhizal symbiosis. Potentially similar results obtained from the photothermal contribution are discussed.

  5. The effect of mycorrhizal fungi on malondialdehyde concentration and some metabolic processes in hyssop (Hyssopus officinalis under water deficit stress

    Directory of Open Access Journals (Sweden)

    Farogh Soleymani

    2015-06-01

    Full Text Available Ion balance and osmotic regulation in plants to mitigate the effects of drought is possible with accumulation of osmolytes like proline and glycine betaine. Accordingly, in order to investigate the effect of mycorrhizal fungai species on the eco-physiological characteristics of hyssop, a factorial experimental based on randomized complete block design with three replications was conducted at the Research Farm of Agriculture and Natural Resources of West Azarbaijan in 2013. Experimental treatments included species of mycorrhizal fungi (Glomus mosseae, G. intraradices, G. fasiculatum, G. claroideum, Acaulospora longula and control without mycorrhiza and four levels of irrigation (irrigation at 80, 70, 60 and 50% of field capacity. The results of ANOVA showed the significant interaction between water deficit and mycorrhizal fungi species on the concentrations of malondialdehyde (MDA, glycine betaine, proline, total soluble carbohydrates and essential oil percent. The highest concentrations of malondialdehyde (MDA (125 nmol/g fresh weight, glycine betaine (2019 μm/g dry weight, proline (111 μm/g fresh weight, essential oil percentage (7.29% and total soluble carbohydrates (396.7 mg/g dry weight were obtained from plants inoculated by G. claroideum, A. longula, A. longula, G. fasiculatum and G. claroideum and irrigated at 50 and 60% field capacity, respectively. The concentration of malondialdehyde (MDA biomarker was increased at non-mycorrhizal plants compared with mycorrhizal one. Overall, this study suggested that the mycorrhizal species were effective to reduce stress and water use efficiency.

  6. Mycorrhizal fungi isolated from native terrestrial orchids of pristine regions in Cordoba (Argentina).

    Science.gov (United States)

    Fernández Di Pardo, Agustina; Chiocchio, Viviana M; Barrera, Viviana; Colombo, Roxana P; Martinez, Alicia E; Gasoni, Laura; Godeas, Alicia M

    2015-03-01

    Orchidaceae is a highly dependent group on the Rhizoctonia complex that includes Ceratorhiza, Moniliopsis, Epulorhiza and Rhizoctonia, for seed germination and the development of new orchid plants. Thus, the isolation and identification of orchid mycorrhizal fungi are important to understand the orchid-fungus relationship, which can lead to the development of efficient conservation strategies by in vivo germination of seeds from endangered orchid plants. The aim of our work was to isolate and characterize the different mycorrhizal fungi found in roots of terrestrial orchids from Cordoba (Argentina), and, to learn about the natural habit and fungal associations in the Chaco Serrano woodland pristine region. In this study, bloomed orchid root and rhizosphere soil samples were obtained in two times from Valle de Punilla during spring of 2007; samples were kept in plastic bags until processed within 48 hours, and mycorrhizal condition confirmed assessing peloton presence. A total of 23 isolates of the orchideous mycorrhizal Rhizoctonia complex were obtained. The isolates were studied based on morphological characters and ITS-rDNA sequences. Morphological characteristics as color of colonies, texture, growth rate, hyphal diameter and length and presence of sclerotia were observed on culture media. To define the number of nuclei per cell, the isolates were grown in Petri dishes containing water-agar (WA) for three days at 25 degrees C and stained with Safranine-O solution. The mycorrhizal fungi were grouped into binucleate (MSGib, 10 isolates) and multinucleate (MSGim, 13 isolates) based on morphological characteristics of the colonies. We obtained the ITS1-5.8s-ITS4 region that was amplified using primers ITSI and ITS4. Based on DNA sequencing, isolates Q23 and Q29 were found to be related to species of Ceratobasidium. Isolates Q24 and Q4 were related to the binucleated anastomosis group AG-C of Rhizoctonia sp. The rest of the isolates grouped in the Ceratobasidium

  7. Mycorrhizal fungi isolated from native terrestrial orchids of pristine regions in Córdoba (Argentina

    Directory of Open Access Journals (Sweden)

    Agustina Fernández Di Pardo

    2015-03-01

    Full Text Available Orchidaceae is a highly dependent group on the Rhizoctonia complex that includes Ceratorhiza, Moniliopsis, Epulorhiza and Rhizoctonia, for seed germination and the development of new orchid plants. Thus, the isolation and identification of orchid mycorrhizal fungi are important to understand the orchid-fungus relationship, which can lead to the development of efficient conservation strategies by in vivo germination of seeds from endangered orchid plants. The aim of our work was to isolate and characterize the different mycorrhizal fungi found in roots of terrestrial orchids from Córdoba (Argentina, and, to learn about the natural habit and fungal associations in the Chaco Serrano woodland pristine region. In this study, bloomed orchid root and rhizosphere soil samples were obtained in two times from Valle de Punilla during spring of 2007; samples were kept in plastic bags until processed within 48 hours, and mycorrhizal condition confirmed assessing peloton presence. A total of 23 isolates of the orchideous mycorrhizal Rhizoctonia complex were obtained. The isolates were studied based on morphological characters and ITS-rDNA sequences. Morphological characteristics as color of colonies, texture, growth rate, hyphal diameter and length and presence of sclerotia were observed on culture media. To define the number of nuclei per cell, the isolates were grown in Petri dishes containing water-agar (WA for three days at 25°C and stained with Safranine-O solution. The mycorrhizal fungi were grouped into binucleate (MSGib, 10 isolates and multinucleate (MSGim, 13 isolates based on morphological characteristics of the colonies. We obtained the ITS1-5.8s-ITS4 region that was amplified using primers ITS1 and ITS4. Based on DNA sequencing, isolates Q23 and Q29 were found to be related to species of Ceratobasidium. Isolates Q24 and Q4 were related to the binucleated anastomosis group AG-C of Rhizoctonia sp. The rest of the isolates grouped in the

  8. Arbuscular mycorrhizal symbiosis mitigates the negative effects of salinity on durum wheat.

    Science.gov (United States)

    Fileccia, Veronica; Ruisi, Paolo; Ingraffia, Rosolino; Giambalvo, Dario; Frenda, Alfonso Salvatore; Martinelli, Federico

    2017-01-01

    Arbuscular mycorrhizal (AM) symbiosis is generally considered to be effective in ameliorating the plant tolerance to salt stress. Unfortunately, the comprehension of the mechanisms implicated in salinity stress alleviation by AM symbiosis is far from being complete. Thus, an experiment was performed by growing durum wheat (Triticum durum Desf.) plants under salt-stress conditions to evaluate the influence of AM symbiosis on both the plant growth and the regulation of a number of genes related to salt stress and nutrient uptake. Durum wheat plants were grown outdoors in pots in absence or in presence of salt stress and with or without AM fungi inoculation. The inoculum consisted of a mixture of spores of Rhizophagus irregularis (formerly Glomus intraradices) and Funneliformis mosseae (formerly G. mosseae). Results indicate that AM symbiosis can alleviate the detrimental effects of salt stress on the growth of durum wheat plants. In fact, under salt stress conditions mycorrhizal plants produced more aboveground and root biomass, had higher N uptake and aboveground N concentration, and showed greater stability of plasma membranes compared to non-mycorrhizal plants. Inoculation with AM fungi had no effect on the expression of the N transporter genes AMT1.1, AMT1.2, and NAR2.2, either under no-stress or salt stress conditions, probably due to the fact that plants were grown under optimal N conditions; on the contrary, NRT1.1 was always upregulated by AM symbiosis. Moreover, the level of expression of the drought stress-related genes AQP1, AQP4, PIP1, DREB5, and DHN15.3 observed in the mycorrhizal stressed plants was markedly lower than that observed in the non-mycorrhizal stressed plants and very close to that observed in the non-stressed plants. Our hypothesis is that, in the present study, AM symbiosis did not increase the plant tolerance to salt stress but instead generated a condition in which plants were subjected to a level of salt stress lower than that of non-mycorrhizal

  9. Evaluation of Mycorrhizal Fungi, Vermicompost and Humic Acid on Essence Yield and Root Colonization of Fennel

    Directory of Open Access Journals (Sweden)

    I. Akbari

    2016-02-01

    Full Text Available Introduction The main objective of sustainable agriculture is to decrease the off-farm inputs such as chemical fertilizers, increased farm nutrient cycle through reduced tillage and the use of biological and organic fertilizers. Studies on medicinal plants indicates that the use of sustainable farming systems provide the best conditions for the production of these plants. Mycorrhizal fungi, vermicompost and humic acid are samples of biological and organic fertilizer that can be used, to eliminate or substantially reduce the use of chemical inputs in order to increase the quantity, quality and stability of the products. Mycorrhizal fungi are one of the most important rhizosphere microorganisms which have symbiotic relation with root of most crops. Mycorrhizal symbiosis improves the soil physical (through expansion of hyphae of fungus, chemical (through increased absorption of nutrients and biological (the soil food web quality. These fungus increased nutrient uptake, such as phosphorus and some micronutrients, water uptake, reducing the negative effects of environmental stress and increase resistance to pathogens and improve the quality of their host plants. Fennel (Foeniculum vulgare Mill is one of the most important medicinal plants, as the essential oil from the seeds used in a variety of industries, pharmaceutical, food and cosmetic use. Anethole is important component of the essential oil of fennel seed. Materials and Methods This experiment was conducted as a factorial based on randomized complete block design in order to evaluate the effects of vermicompost application, humic acid and mycorrhizal fungi on quantitative and qualitative aspects of fennel yield at experimental farm of Shahrood University during growing season of 1391-92. This experiment includes 12 treatments and 3 applications. Vermicompost levels include: v1 (no application v2 (4 ton ha-1 v3 (8 ton ha-1. Mycorrhizal fungi include: m1 (no inoculation and m2 (inoculation and

  10. Haustorium formation in Medicago truncatula roots infected by Phytophthora palmivora does not involve the common endosymbiotic program shared by AM fungi and rhizobia

    NARCIS (Netherlands)

    Huisman, Rik; Bouwmeester, Klaas|info:eu-repo/dai/nl/314625461; Brattinga, Marijke; Govers, Francine; Bisseling, Ton; Limpens, Erik

    2015-01-01

    In biotrophic plant-microbe interactions, microbes infect living plant cells where they are hosted in a novel membrane compartment; the host-microbe interface. To create a host-microbe interface, arbuscular mycorrhizal (AM) fungi and rhizobia make use of the same endosymbiotic program. It is a

  11. Dioecious species and arbuscular mycorrhizal symbioses: the case of Antennaria dioica.

    Science.gov (United States)

    Vega-Frutis, Rocío; Varga, Sandra; Kytöviita, Minna-Maarit

    2013-03-01

    Sex-specific interactions with herbivores and pollinators have been observed in female and male plants of dioecious species. However, only a limited number of studies have revised sex-specific patterns in mycorrhizal symbiosis. To test whether female and male plants of Antennaria dioica differ in their relationship with arbuscular mycorrhizal (AM) fungi, we examined the temporal and spatial variation in AM fungi in female, male and non-reproductive A. dioica plants in three natural populations in Finland during flowering and after seed production. Our results are consistent with previous studies both under greenhouse and field conditions with the same species showing differences in AM colonization between the sexes linked with allocation to reproduction. Taken together, the results indicate that there is a sex-specific interaction between A. dioica and AM fungi. Overall, females have a greater investment in AM fungi, likely to enhance their uptake of soil nutrients and support the reproduction by seed.

  12. Effect of potassium and phosphorus on the transport of radiocesium by arbuscular mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Gyuricza, Veronika; Dupre de Boulois, Herve [Universite catholique de Louvain, Unite de microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Declerck, Stephane, E-mail: stephan.declerck@uclouvain.b [Universite catholique de Louvain, Unite de microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)

    2010-06-15

    Potassium, a chemical analogue of cesium, and phosphorus, an essential macronutrient transported by arbuscular mycorrhizal fungi (AMF), have been suggested to influence the transport of radiocesium by AMF. However, no study investigated the effects of increasing concentrations of both elements on the importance of this transport. Here, the arbuscular mycorrhizal-plant (AM-P) in vitro culture system associating Medicago truncatula plantlets with Glomus intraradices was used to evaluate this effect. Using three concentrations of K (0, 1, 10 mM) and two concentrations of P (30 and 3000 muM) added to a compartment only accessible to the AMF, we demonstrated that K and P individually and in combination significantly influenced radiocesium transport by AMF. Whilst increased concentration of K decreased the amount of radiocesium transported, the opposite was observed for P. Although the exact mechanisms involved need to be assessed, both elements were identified as important factors influencing the transport of radiocesium by AMF.

  13. Effect of four species of arbuscular mycorrhizal fungi on the production of tomato fruits

    Directory of Open Access Journals (Sweden)

    Juan Francisco Ley-Rivas

    2015-06-01

    Full Text Available The effect of native arbuscular mycorrhizal fungi (AMF Glomus sp. 1, Glomus sp. 2, Glomus clarum and Glomus intraradices on tomato (Solanum lycopersicum L. Var., amalia was evaluated under controlled conditions by means of growth variables (height, stem diameter, number of leaves, flowers and fruits, dry aerial and underground biomass and fresh mass of fruits and the mycorrhizal variables (colonization, visual density, quantification of endophyte, external mycelium and spores. The strains Glomus sp. 1 and Glomus intraradices were the most efficient, with harvest index values of 65 and 56.3% and fruit fresh weight of 166.7 and 131.8 g, respectively. It is emphasized that the fungal strain Glomus sp. 1 always presented lower values than strain Glomus intraradices.

  14. Arbuscular mycorrhizal fungi can induce the production of phytochemicals in sweet basil irrespective of phosphorus nutrition.

    Science.gov (United States)

    Toussaint, J-P; Smith, F A; Smith, S E

    2007-06-01

    The potential of three arbuscular mycorrhizal fungi (AMF) to enhance the production of antioxidants (rosmarinic and caffeic acids, RA and CA) was investigated in sweet basil (Ocimum basilicum). After adjusting phosphorus (P) nutrition so that P concentrations and yield were matched in AM and non-mycorrhizal (NM) plants we demonstrated that Glomus caledonium increased RA and CA production in the shoots. Glomus mosseae also increased shoot CA concentration in basil under similar conditions. Although higher P amendments to NM plants increased RA and CA concentrations, there was higher production of RA and CA in the shoots of AM plants, which was not solely due to better P nutrition. Therefore, AMF potentially represent an alternative way of promoting growth of this important medicinal herb, as natural ways of growing such crops are currently highly sought after in the herbal industry.

  15. In Winter Wheat, No-Till Increases Mycorrhizal Colonization thus Reducing the Need for Nitrogen Fertilization

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    Julien Verzeaux

    2016-06-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF play a major role in the uptake of nutrients by agricultural plants. Nevertheless, some agricultural practices can interrupt fungal-plant signaling and thus impede the establishment of the mycorrhizal symbiosis. A field experiment performed over a 5-year period demonstrated that both the absence of tillage and of nitrogen (N fertilization improved AMF colonization of wheat roots. Moreover, under no-till conditions, N uptake and aboveground biomass production did not vary significantly between N-fertilized and N-unfertilized plots. In contrast, both N uptake and above ground biomass were much lower when N fertilizer was not added during conventional tillage. This finding strongly suggests that for wheat, no-till farming is a sustainable agricultural system that allows a gradual reduction in N fertilizer use by promoting AMF functionality and at the same time increasing N uptake.

  16. Convergent losses of decay mechanisms and rapid turnover of symbiosis genes in mycorrhizal mutualists.

    Science.gov (United States)

    Kohler, Annegret; Kuo, Alan; Nagy, Laszlo G; Morin, Emmanuelle; Barry, Kerrie W; Buscot, Francois; Canbäck, Björn; Choi, Cindy; Cichocki, Nicolas; Clum, Alicia; Colpaert, Jan; Copeland, Alex; Costa, Mauricio D; Doré, Jeanne; Floudas, Dimitrios; Gay, Gilles; Girlanda, Mariangela; Henrissat, Bernard; Herrmann, Sylvie; Hess, Jaqueline; Högberg, Nils; Johansson, Tomas; Khouja, Hassine-Radhouane; LaButti, Kurt; Lahrmann, Urs; Levasseur, Anthony; Lindquist, Erika A; Lipzen, Anna; Marmeisse, Roland; Martino, Elena; Murat, Claude; Ngan, Chew Y; Nehls, Uwe; Plett, Jonathan M; Pringle, Anne; Ohm, Robin A; Perotto, Silvia; Peter, Martina; Riley, Robert; Rineau, Francois; Ruytinx, Joske; Salamov, Asaf; Shah, Firoz; Sun, Hui; Tarkka, Mika; Tritt, Andrew; Veneault-Fourrey, Claire; Zuccaro, Alga; Tunlid, Anders; Grigoriev, Igor V; Hibbett, David S; Martin, Francis

    2015-04-01

    To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall-degrading enzymes (PCWDEs), as compared to their ancestral wood decayers. Nevertheless, they have retained a unique array of PCWDEs, thus suggesting that they possess diverse abilities to decompose lignocellulose. Similar functional categories of nonorthologous genes are induced in symbiosis. Of induced genes, 7-38% are orphan genes, including genes that encode secreted effector-like proteins. Convergent evolution of the mycorrhizal habit in fungi occurred via the repeated evolution of a 'symbiosis toolkit', with reduced numbers of PCWDEs and lineage-specific suites of mycorrhiza-induced genes.

  17. Two putative-aquaporin genes are differentially expressed during arbuscular mycorrhizal symbiosis in Lotus japonicus

    Science.gov (United States)

    2012-01-01

    Background Arbuscular mycorrhizas (AM) are widespread symbioses that provide great advantages to the plant, improving its nutritional status and allowing the fungus to complete its life cycle. Nevertheless, molecular mechanisms that lead to the development of AM symbiosis are not yet fully deciphered. Here, we have focused on two putative aquaporin genes, LjNIP1 and LjXIP1, which resulted to be upregulated in a transcriptomic analysis performed on mycorrhizal roots of Lotus japonicus. Results A phylogenetic analysis has shown that the two putative aquaporins belong to different functional families: NIPs and XIPs. Transcriptomic experiments have shown the independence of their expression from their nutritional status but also a close correlation with mycorrhizal and rhizobial interaction. Further transcript quantification has revealed a good correlation between the expression of one of them, LjNIP1, and LjPT4, the phosphate transporter which is considered a marker gene for mycorrhizal functionality. By using laser microdissection, we have demonstrated that one of the two genes, LjNIP1, is expressed exclusively in arbuscule-containing cells. LjNIP1, in agreement with its putative role as an aquaporin, is capable of transferring water when expressed in yeast protoplasts. Confocal analysis have demonstrated that eGFP-LjNIP1, under its endogenous promoter, accumulates in the inner membrane system of arbusculated cells. Conclusions Overall, the results have shown different functionality and expression specificity of two mycorrhiza-inducible aquaporins in L. japonicus. One of them, LjNIP1 can be considered a novel molecular marker of mycorrhizal status at different developmental stages of the arbuscule. At the same time, LjXIP1 results to be the first XIP family aquaporin to be transcriptionally regulated during symbiosis. PMID:23046713

  18. OCCURRENCE OF ARBUSCULAR MYCORRHIZAL FUNGI IN SOME MEDICINAL PLANTS OF KERALA

    Science.gov (United States)

    Mathew, Abraham; Malathy, M.R.

    2006-01-01

    The occurrence of mycorrhiza in 40 selected medicinal plants was studied. The percentage of mycorrhizal colonization in each of the plant was calculated. The colonization was found to be very less in four plants and very high in six plants. All others showed a moderate level of colonization. The present work suggests the use of mycorrhiza as a biofertilizer to enhance the growth and yield of medicinal plants. PMID:22557224

  19. Using deep RNA sequencing for the structural annotation of the Laccaria bicolor mycorrhizal transcriptome.

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    Peter E Larsen

    Full Text Available BACKGROUND: Accurate structural annotation is important for prediction of function and required for in vitro approaches to characterize or validate the gene expression products. Despite significant efforts in the field, determination of the gene structure from genomic data alone is a challenging and inaccurate process. The ease of acquisition of transcriptomic sequence provides a direct route to identify expressed sequences and determine the correct gene structure. METHODOLOGY: We developed methods to utilize RNA-seq data to correct errors in the structural annotation and extend the boundaries of current gene models using assembly approaches. The methods were validated with a transcriptomic data set derived from the fungus Laccaria bicolor, which develops a mycorrhizal symbiotic association with the roots of many tree species. Our analysis focused on the subset of 1501 gene models that are differentially expressed in the free living vs. mycorrhizal transcriptome and are expected to be important elements related to carbon metabolism, membrane permeability and transport, and intracellular signaling. Of the set of 1501 gene models, 1439 (96% successfully generated modified gene models in which all error flags were successfully resolved and the sequences aligned to the genomic sequence. The remaining 4% (62 gene models either had deviations from transcriptomic data that could not be spanned or generated sequence that did not align to genomic sequence. The outcome of this process is a set of high confidence gene models that can be reliably used for experimental characterization of protein function. CONCLUSIONS: 69% of expressed mycorrhizal JGI "best" gene models deviated from the transcript sequence derived by this method. The transcriptomic sequence enabled correction of a majority of the structural inconsistencies and resulted in a set of validated models for 96% of the mycorrhizal genes. The method described here can be applied to improve gene

  20. Carbon and nitrogen metabolism in arbuscular mycorrhizal maize plants under low-temperature stress

    DEFF Research Database (Denmark)

    Zhu, Xian-Can; Song, Feng-Bin; Liu, Fulai

    2015-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 258C for 4 weeks...... temperature regimes. AM symbiosis modulated C metabolic enzymes, thereby inducing an accumulation of soluble sugars, which may have contributed to an increased tolerance to low temperature, and therefore higher Pn in maize plants....