WorldWideScience

Sample records for arbuscular mycorrhizal fungal

  1. 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.

  2. Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in South Indian Aquatic and Wetland Macrophytes

    OpenAIRE

    Kumar Seerangan; Muthukumar Thangavelu

    2014-01-01

    Investigations on the prevalence of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal symbioses are limited for plants growing in tropical aquatic and wetland habitats compared to those growing on terrestrial moist or dry habitats. Therefore, we assessed the incidence of AM and DSE symbiosis in 8 hydrophytes and 50 wetland plants from four sites in south India. Of the 58 plant species examined, we found AM and DSE fungal symbiosis in 21 and five species, respectively. We rep...

  3. Arbuscular mycorrhizal fungal communities are phylogenetically clustered at small scales.

    Science.gov (United States)

    Horn, Sebastian; Caruso, Tancredi; Verbruggen, Erik; Rillig, Matthias C; Hempel, Stefan

    2014-11-01

    Next-generation sequencing technologies with markers covering the full Glomeromycota phylum were used to uncover phylogenetic community structure of arbuscular mycorrhizal fungi (AMF) associated with Festuca brevipila. The study system was a semi-arid grassland with high plant diversity and a steep environmental gradient in pH, C, N, P and soil water content. The AMF community in roots and rhizosphere soil were analyzed separately and consisted of 74 distinct operational taxonomic units (OTUs) in total. Community-level variance partitioning showed that the role of environmental factors in determining AM species composition was marginal when controlling for spatial autocorrelation at multiple scales. Instead, phylogenetic distance and spatial distance were major correlates of AMF communities: OTUs that were more closely related (and which therefore may have similar traits) were more likely to co-occur. This pattern was insensitive to phylogenetic sampling breadth. Given the minor effects of the environment, we propose that at small scales closely related AMF positively associate through biotic factors such as plant-AMF filtering and interactions within the soil biota.

  4. Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses.

    Science.gov (United States)

    Wu, Songlin; Zhang, Xin; Sun, Yuqing; Wu, Zhaoxiang; Li, Tao; Hu, Yajun; Lv, Jitao; Li, Gang; Zhang, Zhensong; Zhang, Jing; Zheng, Lirong; Zhen, Xiangjun; Chen, Baodong

    2016-10-01

    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.

  5. Mechanical soil disturbance as a determinant of arbuscular mycorrhizal fungal communities in semi-natural grassland

    DEFF Research Database (Denmark)

    Schnoor, Tim Krone; Lekberg, Ylva; Rosendahl, Søren

    2011-01-01

    to Diversisporaceae. Only three phylotypes were closely related to known morphospecies. Soil disturbance significantly reduced phylotype richness and changed the AM fungal community composition. Most phylotypes, even closely related ones, showed little or no overlap in their distribution and occurred in either......While the effect of disturbance on overall abundance and community composition of arbuscular mycorrhizal (AM) fungi has been researched in agricultural fields, less is known about the impact in semi-natural grasslands. We sampled two AM plant species, Festuca brevipila and Plantago lanceolata, from...

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

    Science.gov (United States)

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

    2012-02-14

    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. AM fungi take up nutrients from the soil and exchange them against photosynthetically fixed carbon (C) from the host. Recent studies have demonstrated that reciprocal reward strategies by plant and fungal partners guarantee a "fair trade" of phosphorus against C between partners [Kiers ET, et al. (2011) Science 333:880-882], but whether a similar reward mechanism also controls nitrogen (N) flux in the AM symbiosis is not known. Using mycorrhizal root organ cultures, we manipulated the C supply to the host and fungus and followed the uptake and transport of N sources in the AM symbiosis, the enzymatic activities of arginase and urease, and fungal gene expression in the extraradical and intraradical mycelium. We found that the C supply of the host plant triggers the uptake and transport of N in the symbiosis, and that the increase in N transport is orchestrated by changes in fungal gene expression. N transport in the symbiosis is stimulated only when the C is delivered by the host across the mycorrhizal interface, not when C is supplied directly to the fungal extraradical mycelium in the form of acetate. These findings support the importance of C flux from the root to the fungus as a key trigger for N uptake and transport and provide insight into the N transport regulation in the AM symbiosis.

  7. [Response of arbuscular mycorrhizal fungal lipid metabolism to symbiotic signals in mycorrhiza].

    Science.gov (United States)

    Tian, Lei; Li, Yuanjing; Tian, Chunjie

    2016-01-04

    Arbuscular mycorrhizal (AM) fungi play an important role in energy flow and nutrient cycling, besides their wide distribution in the cosystem. With a long co-evolution, AM fungi and host plant have formed a symbiotic relationship, and fungal lipid metabolism may be the key point to find the symbiotic mechanism in arbusculart mycorrhiza. Here, we reviewed the most recent progress on the interaction between AM fungal lipid metabolism and symbiotic signaling networks, especially the response of AM fungal lipid metabolism to symbiotic signals. Furthermore, we discussed the response of AM fungal lipid storage and release to symbiotic or non-symbiotic status, and the correlation between fungal lipid metabolism and nutrient transfer in mycorrhiza. In addition, we explored the feedback of the lipolysis process to molecular signals during the establishment of symbiosis, and the corresponding material conversion and energy metabolism besides the crosstalk of fungal lipid metabolism and signaling networks. This review will help understand symbiotic mechanism of arbuscular mycorrhiza fungi and further application in ecosystem.

  8. Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in South Indian Aquatic and Wetland Macrophytes

    Directory of Open Access Journals (Sweden)

    Kumar Seerangan

    2014-01-01

    Full Text Available Investigations on the prevalence of arbuscular mycorrhizal (AM and dark septate endophyte (DSE fungal symbioses are limited for plants growing in tropical aquatic and wetland habitats compared to those growing on terrestrial moist or dry habitats. Therefore, we assessed the incidence of AM and DSE symbiosis in 8 hydrophytes and 50 wetland plants from four sites in south India. Of the 58 plant species examined, we found AM and DSE fungal symbiosis in 21 and five species, respectively. We reported for the first time AM and DSE fungal symbiosis in seven and five species, respectively. Intermediate-type AM morphology was common, and AM morphology is reported for the first time in 16 plant species. Both AM and DSE fungal colonization varied significantly across plant species and sites. Intact and identifiable AM fungal spores occurred in root zones of nine plant species, but AM fungal species richness was low. Though no clear relationship between AM and DSE fungal colonization was recognized, a significant negative correlation between AM colonization and spore numbers was established. Our study suggests that the occurrence of AM and DSE fungal symbiosis in plants growing in hydrophytic and wetland habitats is not as common as in terrestrial habitats.

  9. Anthropogenic land use shapes the composition and phylogenetic structure of soil arbuscular mycorrhizal fungal communities.

    Science.gov (United States)

    Moora, Mari; Davison, John; Öpik, Maarja; Metsis, Madis; Saks, Ülle; Jairus, Teele; Vasar, Martti; Zobel, Martin

    2014-12-01

    Arbuscular mycorrhizal (AM) fungi play an important role in ecosystems, but little is known about how soil AM fungal community composition varies in relation to habitat type and land-use intensity. We molecularly characterized AM fungal communities in soil samples (n = 88) from structurally open (permanent grassland, intensive and sustainable agriculture) and forested habitats (primeval forest and spruce plantation). The habitats harboured significantly different AM fungal communities, and there was a broad difference in fungal community composition between forested and open habitats, the latter being characterized by higher average AM fungal richness. Within both open and forest habitats, intensive land use significantly influenced community composition. There was a broad difference in the phylogenetic structure of AM fungal communities between mechanically disturbed and nondisturbed habitats. Taxa from Glomeraceae served as indicator species for the nondisturbed habitats, while taxa from Archaeosporaceae, Claroideoglomeraceae and Diversisporaceae were indicators for the disturbed habitats. The distribution of these indicator taxa among habitat types in the MaarjAM global database of AM fungal diversity was in accordance with their local indicator status.

  10. 454-sequencing reveals stochastic local reassembly and high disturbance tolerance within arbuscular mycorrhizal fungal communities

    DEFF Research Database (Denmark)

    Lekberg, Karin Ylva Margareta; Schnoor, Tim; Kjøller, Rasmus

    2012-01-01

    1. Disturbance is assumed to be a major driver of plant community composition, but whether similar processes operate on associated soil microbial communities is less known. Based on the assumed trade-off between disturbance tolerance and competiveness, we hypothesize that a severe disturbance......, disturbance did not significantly alter the community composition and OTU richness. Instead, OTU abundances were positively correlated across treatments; i.e., common OTUs in undisturbed soil were also common after the severe disturbance. However, the distribution of OTUs within and between plots was largely...... applied within a semi-natural grassland would shift the arbuscular mycorrhizal (AM) fungal community towards disturbance-tolerant fungi that are rare in undisturbed soils. 2. We used 454-sequencing of the large subunit rDNAregion to characterizeAMfungal communities in Plantago lanceolata roots grown...

  11. Variation of soil arbuscular mycorrhizal fungal communities across land use gradient

    Science.gov (United States)

    Moora, M.; Davison, J.; Metsis, M.; Öpik, M.; Vasar, M.; Zobel, M.

    2012-04-01

    Arbuscular mycorrhizal (AM) fungi (phylum Glomeromycota) colonize the roots of most terrestrial plants, facilitating mineral nutrient uptake from soil in exchange for plant-assimilated carbon. While investigating functional aspects of plant-AM fungi interactions has been a major focus of research, there is increasing interest in describing and explaining the distribution of AM fungal diversity. Different management practices has been shown to influence the AM fungal communities while more intense management can bring along the loss of AM fungal diversity. Such a loss may have negative consequences on ecosystem service delivery, primary production and soil sustainability. However, due to cryptic lifestyle of AM fungi, relatively few information is available about variability of diversity and composition of AM fungal communities in the soils from differently managed ecosystems. To study the variation of soil AM fungal communities in response to the land use intensity, replicated soil samples were collected along land use gradient from intensively managed agricultural fields, organic fields, forest plantations and managed natural forest to primeval forest in Estonia. Soil AM fungal communities were described using molecular tools: DNA extraction, amplicon isolation and 454 large scale parallel pyrosequencing. Glomeromycota sequences were amplified using the SSU rDNA primers NS31 and AML2. We shall analyse and describe AM fungal community changes along land use intensity gradient and seek finding indicator taxa characteristic to particular land use types. We shall also address changes in the diversity of AM fungal taxa and check whether the decrease of diversity along land use intensity is a ubiquitous phenomenon.

  12. Rapid assessment of acid phosphatase activity in the mycorrhizosphere and in arbuscular mycorrhizal fungal hyphae

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A pot experiment has been carried out under controlled conditions to study the possibility of applying the technique of in vivo staining for acid phosphatase activity on the roots of mycorrhizal plants and arbuscular mycorrhizal hyphae. The pots had 5 compartments. The central root compartment was separated from the two adjacent hyphal compartments using nylon nets of 30 m m mesh, and the two hyphal compartments were separated from the two outermost compartments with 0.45 m m membranes. Red clover was grown in the root compartment and was either inoculated with the arbuscular mycorrhizal fungus (AMF) Glomus mosseae or uninoculated. Sodium phytate was applied to all compartments. The results show that AMF can increase acid phosphatase activity of clover roots. The plant roots acquired deep red "mycorrhizal prints". The external hyphae also had obvious "hyphal prints" on the test papers, indicating the ability of mycorrhizal hyphae to release acid phosphatase.

  13. Diversity and spatial structure of belowground plant-fungal symbiosis in a mixed subtropical forest of ectomycorrhizal and arbuscular mycorrhizal plants.

    Science.gov (United States)

    Toju, Hirokazu; Sato, Hirotoshi; Tanabe, Akifumi S

    2014-01-01

    Plant-mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant-fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant-fungal symbiosis in subtropical forests is complex in that it includes "non-typical" plant-fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in that

  14. 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

  15. Host plant quality mediates competition between arbuscular mycorrhizal fungi

    NARCIS (Netherlands)

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

    2014-01-01

    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

  16. Biases for detecting arbuscular mycorrhizal fungal mixture by terminal restriction fragment length polymorphism (T-RFLP).

    Science.gov (United States)

    Watanarojanaporn, N; Longtonglang, A; Boonkerd, N; Tittabutr, P; Lee, J; Teaumroong, N

    2014-01-01

    Terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified ribosomal RNA genes is used for profiling microbial communities and sometimes for species richness and relative abundance estimation in environmental samples. However, the T-RFLP fingerprint may be subject to biases during the procedure, influencing the detection of real community structures in the environment. To investigate possible sources of T-RFLP bias, 18S rRNA gene clones derived from two arbuscular mycorrhizal fungal sequences were combined in simple pairwise mixes to assess the effects of polymerase chain reaction cycle number, plant genomic DNA purification method and varying template ratio on the template-to-product ratio as measured by relative T-RF peak area. Varying cycle numbers indicated that amplification was still in the exponential phase at the cycle numbers lower than 18, so these small cycle numbers were used for the comparison of template-to-product quantities. Relative abundance estimated from T-RF peak ratios varied with different purification procedures, but the best results, closest to input ratios, were obtained by using phenol-chloroform purification. The presence of an excess of unpurified non-target plant genomic DNA generated a bias towards lower or overestimation of relative abundance. We conclude that a low number of amplification cycles and stringent DNA purification are necessary for accurate mixed sample analysis by T-RFLP.

  17. Characterization of arbuscular mycorrhizal fungal communities with respect to zonal vegetation in a coastal dune ecosystem.

    Science.gov (United States)

    Kawahara, Ai; Ezawa, Tatsuhiro

    2013-10-01

    Coastal dune vegetation distributes zonally along the environmental gradients of, e.g., soil disturbance. In the preset study, arbuscular mycorrhizal fungal communities in a coastal dune ecosystem were characterized with respect to tolerance to soil disturbance. Two grass species, Elymus mollis and Miscanthus sinensis, are distributed zonally in the seaward and landward slopes, respectively, in the primary dunes in Ishikari, Japan. The seaward slope is severely disturbed by wind, while the landward slope is stabilized by the thick root system of M. sinensis. The roots and rhizosphere soils of the two grasses were collected from the slopes. The soils were sieved to destruct the fungal hyphal networks, and soil trap culture was conducted to assess tolerance of the communities to disturbance, with parallel analysis of the field communities using a molecular ecological tool. In the landward communities, large shifts in the composition and increases in diversity were observed in the trap culture compared with the field, but in the seaward communities, the impact of trap culture was minimal. The landward field community was significantly nested within the landward trap culture community, implying that most members in the field community did not disappear in the trap culture. No nestedness was observed in the seaward communities. These observations suggest that disturbance-tolerant fungi have been preferentially selected in the seaward slope due to severe disturbance in the habitat. Whereas a limited number of fungi, which are not necessarily disturbance-sensitive, dominate in the stable landward slope, but high-potential diversity has been maintained in the habitat.

  18. Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers

    Science.gov (United States)

    Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

    2016-01-01

    Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further

  19. Organic nitrogen-driven stimulation of arbuscular mycorrhizal fungal hyphae correlates with abundance of ammonia oxidizers

    Directory of Open Access Journals (Sweden)

    Petra eBukovská

    2016-05-01

    Full Text Available Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass, while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples

  20. The role of carbon in fungal nutrient uptake and transport: implications for resource exchange in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Fellbaum, Carl R; Mensah, Jerry A; Pfeffer, Philip E; Kiers, E Toby; Bücking, Heike

    2012-11-01

    The arbuscular mycorrhizal (AM) symbiosis, which forms between plant hosts and ubiquitous soil fungi of the phylum Glomeromycota, plays a key role for the nutrient uptake of the majority of land plants, including many economically important crop species. AM fungi take up nutrients from the soil and exchange them for photosynthetically fixed carbon from the host. While our understanding of the exact mechanisms controlling carbon and nutrient exchange is still limited, we recently demonstrated that (i) carbon acts as an important trigger for fungal N uptake and transport, (ii) the fungus changes its strategy in response to an exogenous supply of carbon, and that (iii) both plants and fungi reciprocally reward resources to those partners providing more benefit. Here, we summarize recent research findings and discuss the implications of these results for fungal and plant control of resource exchange in the AM symbiosis.

  1. Local adaptation to soil hypoxia determines the structure of an arbuscular mycorrhizal fungal community in roots from natural CO₂ springs.

    Science.gov (United States)

    Maček, Irena; Dumbrell, Alex J; Nelson, Michaela; Fitter, Alastair H; Vodnik, Dominik; Helgason, Thorunn

    2011-07-01

    The processes responsible for producing and maintaining the diversity of natural arbuscular mycorrhizal (AM) fungal communities remain largely unknown. We used natural CO(2) springs (mofettes), which create hypoxic soil environments, to determine whether a long-term, directional, abiotic selection pressure could change AM fungal community structure and drive the selection of particular AM fungal phylotypes. We explored whether those phylotypes that appear exclusively in hypoxic soils are local specialists or widespread generalists able to tolerate a range of soil conditions. AM fungal community composition was characterized by cloning, restriction fragment length polymorphism typing, and the sequencing of small subunit rRNA genes from roots of four plant species growing at high (hypoxic) and low (control) geological CO(2) exposure. We found significant levels of AM fungal community turnover (β diversity) between soil types and the numerical dominance of two AM fungal phylotypes in hypoxic soils. Our results strongly suggest that direct environmental selection acting on AM fungi is a major factor regulating AM fungal communities and their phylogeographic patterns. Consequently, some AM fungi are more strongly associated with local variations in the soil environment than with their host plant's distribution.

  2. Relative importance of deterministic and stochastic processes in driving arbuscular mycorrhizal fungal assemblage during the spreading of a toxic plant.

    Directory of Open Access Journals (Sweden)

    Guoxi Shi

    Full Text Available Both deterministic and stochastic processes are expected to drive the assemblages of arbuscular mycorrhizal (AM fungi, but little is known about the relative importance of these processes during the spreading of toxic plants. Here, the species composition and phylogenetic structure of AM fungal communities colonizing the roots of a toxic plant, Ligularia virgaurea, and its neighborhood plants, were analyzed in patches with different individual densities of L. virgaurea (represents the spreading degree. Community compositions of AM fungi in both root systems were changed significantly by the L. virgaurea spreading, and also these communities fitted the neutral model very well. AM fungal communities in patches with absence and presence of L. virgaurea were phylogenetically random and clustered, respectively, suggesting that the principal ecological process determining AM fungal assemblage shifted from stochastic process to environmental filtering when this toxic plant was present. Our results indicate that deterministic and stochastic processes together determine the assemblage of AM fungi, but the dominant process would be changed by the spreading of toxic plants, and suggest that the spreading of toxic plants in alpine meadow ecosystems might be involving the mycorrhizal symbionts.

  3. Suppression of allene oxide synthase 3 in potato increases degree of arbuscular mycorrhizal fungal colonization.

    Science.gov (United States)

    Morcillo, Rafael Jorge León; Navarrete, María Isabel Tamayo; Bote, Juan Antonio Ocampo; Monguio, Salomé Prat; García-Garrido, José Manuel

    2016-01-15

    Arbuscular mycorrhizal (AM) is a mutually beneficial interaction among higher plants and soil fungi of the phylum Glomeromycota. Numerous studies have pointed that jasmonic acid plays an important role in the development of the intraradical fungus. This compound belongs to a group of biologically active compounds known as oxylipins which are derived from the oxidative metabolism of polyunsaturated fatty acids. Studies of the regulatory role played by oxylipins in AM colonization have generally focused on jasmonates, while few studies exist on the 9-LOX pathway of oxylipins during AM formation. Here, the cDNA of Allene oxide synthase 3 (AOS3), a key enzyme in the 9-LOX pathway, was used in the RNA interference (RNAi) system to transform potato plants in order to suppress its expression. Results show increases in AOS3 gene expression and 9-LOX products in roots of wild type potato mycorrhizal plants. The suppression of AOS3 gene expression increases the percentage of root with mycorrhizal colonization at early stages of AM formation. AOS3 RNA interference lead to an induction of LOXA and 13-LOX genes, a reduction in AOS3 derived 9-LOX oxylipin compounds and an increase in jasmonic acid content, suggesting compensation between 9 and 13-LOX pathways. The results in a whole support the hypothesis of a regulatory role for the 9-LOX oxylipin pathway during mycorrhization.

  4. The interactions between plant life form and fungal traits of arbuscular mycorrhizal fungi determine the symbiotic community.

    Science.gov (United States)

    López-García, Álvaro; Azcón-Aguilar, Concepción; Barea, José M

    2014-12-01

    Arbuscular mycorrhizal (AM) fungi have traditionally been considered generalist symbionts. However, an increasing number of studies are pointing out the selectivity potential of plant hosts. Plant life form, determined by plant life history traits, seems to drive the AM fungal community composition. The AM fungi also exhibit a wide diversity of functional traits known to be responsible for their distribution in natural ecosystems. However, little is known about the role of plant and fungal traits driving the resultant symbiotic assemblages. With the aim of testing the feedback relationship between plant and fungal traits on the resulting AM fungal community, we inoculated three different plant life forms, i.e. annual herbs, perennial herbs and perennial semi-woody plants, with AM fungal communities sampled in different seasons. We hypothesized that the annual climate variation will induce changes in the mean traits of the AM fungal communities present in the soil throughout the year. Furthermore, the association of plants with different life forms with AM fungi with contrasting life history traits will show certain preferences according to reciprocal traits of the plants and fungi. We found changes in the AM fungal community throughout the year, which were differentially disrupted by disturbance and altered by plant growth form and plant biomass. Both plant and fungal traits clearly contributed to the resultant AM fungal communities. The revealed process can have implications for the functioning of ecosystems since changes in dominant plant life forms or climatic variables could influence the traits of AM fungal communities in soil and hence ecosystem processes.

  5. High compatibility between arbuscular mycorrhizal fungal communities and seedlings of different land use types in a tropical dry ecosystem.

    Science.gov (United States)

    Gavito, Mayra E; Pérez-Castillo, Daniel; González-Monterrubio, César F; Vieyra-Hernández, Teresa; Martínez-Trujillo, Miguel

    2008-12-01

    We conducted this study to explore limitations for the establishment of mycorrhizal associations in disturbed areas of the tropical dry ecosystem in the Chamela region of Jalisco, Mexico. Specifically, we: (1) assessed the diversity and composition of arbuscular mycorrhizal fungal (AMF) communities through spore morphospecies identification in three common land uses (primary forest, secondary forest, and pasture), (2) tested the inoculum potential of the AMF communities and the effect of water stress on the establishment of mycorrhizal associations in seedlings of various plant species, and (3) explored the importance of AMF community composition on early seedling development. Soil and root samples were taken from 15 random points in each of three plots established in two primary forests, two 26-year-old secondary forests, and two 26-year-old pastures. We expected that because of soil degradation and management, pastures would have the lowest and primary forests the highest AMF species richness. We found evidence for changes in AMF species composition due to land use and for higher morphospecies richness in primary forests than in secondary forests and pastures. We expected also that water stress limited plant and mycorrhizal development and that plants and AMF communities from secondary forests and pastures would be less affected by (better adapted to) water stress than those from the primary forest. We found that although all plant species showed biomass reductions under water stress, only some of the plant species had lower mycorrhizal development under water stress, and this was regardless of the AMF community inoculated. The third hypothesis was that plant species common to all land use types would respond similarly to all AMF communities, whereas plant species found mainly in one land use type would grow better when inoculated with the AMF community of that specific land use type. All plant species were however equally responsive to the three AMF communities

  6. Seasonality of arbuscular mycorrhizal symbiosis and dark septate endophytes in a grassland site in southwest China.

    Science.gov (United States)

    Lingfei, Li; Anna, Yang; Zhiwei, Zhao

    2005-11-01

    Arbuscular mycorrhizal and dark septate endophytic fungal colonization in a grassland in Kunming, southwest China, was investigated monthly over one year. All plant roots surveyed were co-colonized by arbuscular mycorrhizal and dark septate endophytic fungi in this grassland. Both arbuscular mycorrhizal and dark septate endophytic fungal colonization fluctuated significantly throughout the year, and their seasonal patterns were different in each plant species. The relationships between environmental (climatic and edaphic) factors and fungal colonization were also studied. Correlation analysis demonstrated that arbuscular mycorrhizal colonization was significantly correlative with environmental factors (rainfall, sunlight hours, soil P, etc.), but dark septate endophytic fungal colonization was only correlative with relative humidity and sunlight hours.

  7. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient

    Science.gov (United States)

    Johnson, Bart R.; Bohannan, Brendan; Pfeifer-Meister, Laurel; Mueller, Rebecca; Bridgham, Scott D.

    2016-01-01

    Background: Arbuscular mycorrhizal fungi (AMF) provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. Methods: We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM) was used to determine the direct and indirect effects of experimental warming on AMF colonization. Results: Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. Discussion: A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization. PMID:27280074

  8. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient

    Directory of Open Access Journals (Sweden)

    Hannah Wilson

    2016-06-01

    Full Text Available Background: Arbuscular mycorrhizal fungi (AMF provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. Methods: We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM was used to determine the direct and indirect effects of experimental warming on AMF colonization. Results: Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. Discussion: A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization.

  9. Petroleum hydrocarbon contamination, plant identity and arbuscular mycorrhizal fungal (AMF) community determine assemblages of the AMF spore-associated microbes.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2016-09-01

    The root-associated microbiome is a key determinant of pollutant degradation, soil nutrient availability and plant biomass productivity, but could not be examined in depth prior to recent advances in high-throughput sequencing. Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of vascular plants. They are known to enhance mineral uptake and promote plant growth and are postulated to influence the processes involved in phytoremediation. Amplicon sequencing approaches have previously shown that petroleum hydrocarbon pollutant (PHP) concentration strongly influences AMF community structure in in situ phytoremediation experiments. We examined how AMF communities and their spore-associated microbiomes were structured within the rhizosphere of three plant species growing spontaneously in three distinct waste decantation basins of a former petrochemical plant. Our results show that the AMF community was only affected by PHP concentrations, while the AMF-associated fungal and bacterial communities were significantly affected by both PHP concentrations and plant species identity. We also found that some AMF taxa were either positively or negatively correlated with some fungal and bacterial groups. Our results suggest that in addition to PHP concentrations and plant species identity, AMF community composition may also shape the community structure of bacteria and fungi associated with AMF spores.

  10. Arbuscular mycorrhizal fungal mediation of plant-plant interactions in a marshland plant community.

    Science.gov (United States)

    Zhang, Qian; Sun, Qixiang; Koide, Roger T; Peng, Zhenhua; Zhou, Jinxing; Gu, Xungang; Gao, Weidong; Yu, Meng

    2014-01-01

    Obligate aerobic AMF taxa have high species richness under waterlogged conditions, but their ecological role remains unclear. Here we focused on AM fungal mediation of plant interactions in a marshland plant community. Five cooccurring plant species were chosen for a neighbor removal experiment in which benomyl was used to suppress AMF colonization. A Phragmites australis removal experiment was also performed to study its role in promoting AMF colonization by increasing rhizosphere oxygen concentration. Mycorrhizal fungal effects on plant interactions were different for dominant and subdominant plant species. AMF colonization has driven positive neighbor effects for three subdominant plant species including Kummerowia striata, Leonurus artemisia, and Ixeris polycephala. In contrast, AMF colonization enhanced the negative effects of neighbors on the dominant Conyza canadensis and had no significant impact on the neighbor interaction to the dominant Polygonum pubescens. AM colonization was positively related to oxygen concentration. P. australis increased oxygen concentration, enhanced AMF colonization, and was thus indirectly capable of influencing plant interactions. Aerobic AM fungi appear to be ecologically relevant in this wetland ecosystem. They drive positive neighbor interactions for subdominant plant species, effectively increasing plant diversity. We suggest, therefore, that AM fungi may be ecologically important even under waterlogged conditions.

  11. Arbuscular Mycorrhizal Fungal Mediation of Plant-Plant Interactions in a Marshland Plant Community

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2014-01-01

    Full Text Available Obligate aerobic AMF taxa have high species richness under waterlogged conditions, but their ecological role remains unclear. Here we focused on AM fungal mediation of plant interactions in a marshland plant community. Five cooccurring plant species were chosen for a neighbor removal experiment in which benomyl was used to suppress AMF colonization. A Phragmites australis removal experiment was also performed to study its role in promoting AMF colonization by increasing rhizosphere oxygen concentration. Mycorrhizal fungal effects on plant interactions were different for dominant and subdominant plant species. AMF colonization has driven positive neighbor effects for three subdominant plant species including Kummerowia striata, Leonurus artemisia, and Ixeris polycephala. In contrast, AMF colonization enhanced the negative effects of neighbors on the dominant Conyza canadensis and had no significant impact on the neighbor interaction to the dominant Polygonum pubescens. AM colonization was positively related to oxygen concentration. P. australis increased oxygen concentration, enhanced AMF colonization, and was thus indirectly capable of influencing plant interactions. Aerobic AM fungi appear to be ecologically relevant in this wetland ecosystem. They drive positive neighbor interactions for subdominant plant species, effectively increasing plant diversity. We suggest, therefore, that AM fungi may be ecologically important even under waterlogged conditions.

  12. Arbuscular mycorrhizal fungal phylogenetic groups differ in affecting host plants along heavy metal levels.

    Science.gov (United States)

    He, Lei; Yang, Haishui; Yu, Zhenxing; Tang, Jianjun; Xu, Ligen; Chen, Xin

    2014-10-01

    Arbuscular mycorrhizal fungi (AMF) are important components of soil microbial communities, and play important role in plant growth. However, the effects of AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) and host plant functional groups (herbs vs. trees, and non-legumes vs. legumes) at three heavy metal levels. In the meta-analysis, we calculate the effect size (ln(RR)) by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels. Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment.

  13. Influence of cultivation regime of an arbuscular mycorrhizal fungal isolate on its symbiotic efficacy in phyto restoration of disturbed ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, R. S.; Vosatka, M.; Castro, P. M. L.; Dodd, J. C.

    2009-07-01

    Arbuscular mycorrhizal fungi (AMF), from the Phylum Glomeromycota, are a group of soil organisms that forms symbiotic associations with plant roots and can contribute to increase plant biomass and promote phyto restoration of disturbed ecosystems. The influence of cultivation regime of a Glomus geosporum isolate, obtained from a highly alkaline anthropogenic sediment, on its symbiotic efficacy was investigated. (Author)

  14. How interacting fungal species and mineral nitrogen inputs affect transfer of nitrogen from litter via arbuscular mycorrhizal mycelium.

    Science.gov (United States)

    He, Yuejun; Cornelissen, J Hans C; Zhong, Zhangcheng; Dong, Ming; Jiang, Changhong

    2017-04-01

    In the karst landscape, widespread in the world including southern China, soil nutrient supply is strongly constrained. In such environments, arbuscular mycorrhizal (AM) fungi may facilitate plant nutrient uptake. However, the possible role of different AM fungal species, and their interactions, especially in transferring nitrogen (N) from litter to plant, is poorly understood. We conducted two microcosm experiments to investigate the role that two karst soil AM fungi, Glomus etunicatum and Glomus mosseae, play in the transfer of N from decomposing litter to the host plant and to determine how N availability influences these processes. In experiment 1, Cinnamomum camphora tree seedlings were grown in compartments inoculated with G. etunicatum. Lolium perenne leaf litter labeled with δ(15)N was added to the soil in unplanted compartments. Compartments containing the δ(15)N labeled litter were either accessible to hyphae but not to seedling roots or were not accessible to hyphae or roots. The addition of mineral N to one of the host compartments at the start of the experiment significantly increased the biomass of the C. camphora seedlings, N content and N:P ratio, AM mycelium length, and soil microbial biomass carbon and N. However, significantly, more δ(15)N was acquired, from the leaf litter by the AM hyphae and transferred to the host when mineral N was not added to the soil. In experiment 2, in which C. camphora seedlings were inoculated with both G. etunicatum and G. mosseae rather than with G. mosseae alone, there was a significant increase in mycelial growth (50.21%), in soil microbial biomass carbon (417.73%) in the rhizosphere, and in the amount of δ(15)N that was transferred to the host. These findings suggest that maintaining AM fungal diversity in karst soils could be important for mediating N transfer from organic material to host plants in N-poor soils.

  15. High functional diversity within species of arbuscular mycorrhizal fungi is associated with differences in phosphate and nitrogen uptake and fungal phosphate metabolism.

    Science.gov (United States)

    Mensah, Jerry A; Koch, Alexander M; Antunes, Pedro M; Kiers, E Toby; Hart, Miranda; Bücking, Heike

    2015-10-01

    Plant growth responses following colonization with different isolates of a single species of an arbuscular mycorrhizal (AM) fungus can range from highly beneficial to detrimental, but the reasons for this high within-species diversity are currently unknown. To examine whether differences in growth and nutritional benefits are related to the phosphate (P) metabolism of the fungal symbiont, the effect of 31 different isolates from 10 AM fungal morphospecies on the P and nitrogen (N) nutrition of Medicago sativa and the P allocation among different P pools was examined. Based on differences in the mycorrhizal growth response, high, medium, and low performance isolates were distinguished. Plant growth benefit was positively correlated to the mycorrhizal effect on P and N nutrition. High performance isolates increased plant biomass by more than 170 % and contributed substantially to both P and N nutrition, whereas the effect of medium performance isolates particularly on the N nutrition of the host was significantly lower. Roots colonized by high performance isolates were characterized by relatively low tissue concentrations of inorganic P and short-chain polyphosphates and a high ratio between long- to short-chain polyphosphates. The high performance isolates belonged to different morphospecies and genera, indicating that the ability to contribute to P and N nutrition is widespread within the Glomeromycota and that differences in symbiotic performance and P metabolism are not specific for individual fungal morphospecies.

  16. Morphotype-based characterization of arbuscular mycorrhizal fungal communities in a restored tropical dry forest, Margarita island-Venezuela.

    Science.gov (United States)

    Fajardo, Laurie; Loveral, Milagros; Arrindell, Pauline; Aguilar, Victor Hugo; Hasmy, Zamira; Cuenca, Gisela

    2015-09-01

    The mycorrhizal component of revegetated areas after ecological restoration or rehabilitation in arid and semiarid tropical areas has been scarcely assessed, particularly those made after mining disturbance. We evaluated and compared the presence of arbuscular mycorrhizal fungi of a small area of restored tropical dry forest destroyed by sand extraction, with a non-restored area of similar age, at the peninsula of Macanao, Margarita Island (Venezuela). Our study was undertaken in 2009, four years after planting, and the mycorrhizal status was evaluated in four restored plots (8 x 12.5 m) (two were previously treated with hydrogel (R2 and R2'), and two were left untreated (R1 and R1'), and four non-restored plots of similar size (NR1 and NR1' with graminoid physiognomy with some scattered shrubs; and NR2 and NR2', with a more species rich plant community). Apparently the restoration management promoted higher arbuscular mycorrhizal fungi (AMF) species richness and diversity, particularly in restored soils where the hydrogel was added (R2 treatment). Soil of the NRI treatment (with a higher herbaceous component) showed the highest spore density, compared to samples of soils under the other treatments. Considering species composition, Claroideoglomus etunicatum and Rhizophagus intraradices were found in all treatments; besides, Diversispora spurca and Funnefformis geosporum were only found in non-restored plots, while members of the Gigasporaceae (a family associated with little disturbed sites) were commonly observed in the plots with restored soils. Mycorrhizal colonization was similar in the restored and non-restored areas, being a less sensitive indicator of the ecosystem recovery. The trend of higher richness and diversity of AMF in the restored plot with hydrogel suggests that this management strategy contributes to accelerate the natural regeneration in those ecosystems where water plays an essential role.

  17. Phosphorus supply, arbuscular mycorrhizal fungal species, and plant genotype impact on the protective efficacy of mycorrhizal inoculation against wheat powdery mildew.

    Science.gov (United States)

    Mustafa, G; Randoux, B; Tisserant, B; Fontaine, J; Magnin-Robert, M; Lounès-Hadj Sahraoui, A; Reignault, Ph

    2016-10-01

    A potential alternative strategy to chemical control of plant diseases could be the stimulation of plant defense by arbuscular mycorrhizal fungi (AMF). In the present study, the influence of three parameters (phosphorus supply, mycorrhizal inoculation, and wheat cultivar) on AMF protective efficiency against Blumeria graminis f. sp. tritici, responsible for powdery mildew, was investigated under controlled conditions. A 5-fold reduction (P/5) in the level of phosphorus supply commonly recommended for wheat in France improved Funneliformis mosseae colonization and promoted protection against B. graminis f. sp. tritici in a more susceptible wheat cultivar. However, a further decrease in P affected plant growth, even under mycorrhizal conditions. Two commercially available AMF inocula (F. mosseae, Solrize®) and one laboratory inoculum (Rhizophagus irregularis) were tested for mycorrhizal development and protection against B. graminis f. sp. tritici of two moderately susceptible and resistant wheat cultivars at P/5. Mycorrhizal levels were the highest with F. mosseae (38 %), followed by R. irregularis (19 %) and Solrize® (SZE, 8 %). On the other hand, the highest protection level against B. graminis f. sp. tritici was obtained with F. mosseae (74 %), followed by SZE (58 %) and R. irregularis (34 %), suggesting that inoculum type rather than mycorrhizal levels determines the protection level of wheat against B. graminis f. sp. tritici. The mycorrhizal protective effect was associated with a reduction in the number of conidia with haustorium and with an accumulation of polyphenolic compounds at B. graminis f. sp. tritici infection sites. Both the moderately susceptible and the most resistant wheat cultivar were protected against B. graminis f. sp. tritici infection by F. mosseae inoculation at P/5, although the underlying mechanisms appear rather different between the two cultivars. This study emphasizes the importance of taking into account the considered

  18. Communities, populations and individuals of arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Rosendahl, Søren

    2008-01-01

    of the asexual resting spores, but molecular approaches to community ecology have revealed a considerable unknown diversity from colonized roots. Although the lack of genetic recombination is not unique in the fungal kingdom, arbuscular mycorrhizal fungi are probably ancient asexuals. The long asexual evolution...

  19. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake

    Energy Technology Data Exchange (ETDEWEB)

    Vogel-Mikus, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Pongrac, Paula [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Kump, Peter [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Necemer, Marijan [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Regvar, Marjana [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)]. E-mail: marjana.regvar@bf.uni-lj.si

    2006-01-15

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment. - Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox with arbuscular mycorrhizal fungi resulted in improved nutrient and reduced Cd and Zn uptake.

  20. Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau

    Science.gov (United States)

    Yang, Wei; Zheng, Yong; Gao, Cheng; Duan, Ji-Chuang; Wang, Shi-Ping; Guo, Liang-Dong

    2016-11-01

    Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow.

  1. Communities, populations and individuals of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    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 asexual resting spores, but molecular approaches to community ecology have revealed a considerable unknown diversity from colonized roots. Although the lack of genetic recombination is not unique in the fungal kingdom, arbuscular mycorrhizal fungi are probably ancient asexuals. The long asexual evolution 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. Arbuscular mycorrhizal fungal community composition is altered by long-term litter removal but not litter addition in a lowland tropical forest.

    Science.gov (United States)

    Sheldrake, Merlin; Rosenstock, Nicholas P; Revillini, Daniel; Olsson, Pål Axel; Mangan, Scott; Sayer, Emma J; Wallander, Håkan; Turner, Benjamin L; Tanner, Edmund V J

    2017-04-01

    Tropical forest productivity is sustained by the cycling of nutrients through decomposing organic matter. Arbuscular mycorrhizal (AM) fungi play a key role in the nutrition of tropical trees, yet there has been little experimental investigation into the role of AM fungi in nutrient cycling via decomposing organic material in tropical forests. We evaluated the responses of AM fungi in a long-term leaf litter addition and removal experiment in a tropical forest in Panama. We described AM fungal communities using 454-pyrosequencing, quantified the proportion of root length colonised by AM fungi using microscopy, and estimated AM fungal biomass using a lipid biomarker. AM fungal community composition was altered by litter removal but not litter addition. Root colonisation was substantially greater in the superficial organic layer compared with the mineral soil. Overall colonisation was lower in the litter removal treatment, which lacked an organic layer. There was no effect of litter manipulation on the concentration of the AM fungal lipid biomarker in the mineral soil. We hypothesise that reductions in organic matter brought about by litter removal may lead to AM fungi obtaining nutrients from recalcitrant organic or mineral sources in the soil, besides increasing fungal competition for progressively limited resources.

  3. Arbuscular mycorrhizal morphology and dark septate fungal associations in medicinal and aromatic plants of Western Ghats, Southern India.

    Science.gov (United States)

    Muthukumar, T; Senthilkumar, M; Rajangam, M; Udaiyan, K

    2006-12-01

    We investigated roots of 107 medicinal and aromatic plants (MAPs) in the Western Ghats region of Southern India for arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) associations. Of the 107 MAPs belonging to 98 genera in 52 families examined, 79 were AM and 38 harbored a DSE association. Typical Arum- and Paris-type mycorrhizas are first reported in the presumed nonmycorrhizal family Amaranthaceae. Similarly, DSE associations are recorded for the first time in nine plant families and 37 plant species. Thirty MAPs had both AM and DSE associations. The number of MAPs having Arum-type mycorrhiza was greater than those having Paris-type. This was more prominent among herbaceous plants than in trees where the Paris-type was predominant. Similarly, the Arum-type was more prevalent in annuals than in perennials. DSE associations were more frequent in herbs and perennials compared to other MAPs.

  4. Arbuscular mycorrhizal fungal colonization of Glycyrrhiza glabra roots enhances plant biomass, phosphorus uptake and concentration of root secondary metabolites

    Institute of Scientific and Technical Information of China (English)

    HongLing LIU; Yong TAN; Monika NELL; Karin ZITTER-EGLSEER; Chris WAWSCRAH; Brigitte KOPP; ShaoMing WANG; Johannes NOVAK

    2014-01-01

    Arbuscular mycorrhizal (AM) fungi penetrate the cortical cells of the roots of vascular plants, and are widely distributed in soil. The formation of these symbiotic bodies accelerates the absorption and utilization of min-eral elements, enhances plant resistance to stress, boosts the growth of plants, and increases the survival rate of transplanted seedlings. We studied the effects of various arbuscular mycorrhizae fungi on the growth and devel-opment of licorice (Glycyrrhiza glabra). Several species of AM, such as Glomus mosseae, Glomus intraradices, and a mixture of fungi (G. mosseae, G. intraradices, G. cladoideum, G. microagregatum, G. caledonium and G. etunica-tum) were used in our study. Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi, plant dry biomass, phosphorus concentration and concentration of secondary metabolites. We estab-lished two cloned strains of licorice, clone 3 (C3) and clone 6 (C6) to exclude the effect of genotypic variations. Our results showed that the AM fungi could in fact increase the leaf and root biomass, as well as the phosphorus con-centration in each clone. Furthermore, AM fungi significantly increased the yield of certain secondary metabolites in clone 3. Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants. There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots.

  5. Comparison of Arbuscular Mycorrhizal Fungal Community in Roots and Rhizosphere of Invasive Cenchrus incertus and Native Plant in Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Dan XIANG; Baodong CHEN; Huan LI; Ruojuan LI; Xin ZHANG

    2016-01-01

    Plant invasions could significantly alter arbuscular mycorrhizal (AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant invasion could improve our understanding of the invasion processes. Here, we examined the AM fungal community composition both in roots and rhizo-sphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia by using terminal restriction fragment length polymorphism analyses (T-RFLP). The results showed that AM fungal abundance in the rhizosphere soils of C. incertus was significantly lower than that of S. viridis. The AM fungal community com-position in the rhizosphere soils of the two plant species also largely differed. In general, AM fungal community structures in roots corresponded very wel to that in rhizosphere soils for both plant species. The dominant AM fungal type both in invasive and native plants was T-RFLP 524bp, which represents Glomus sp. (Virtual taxa 109 and 287). Three specific T-RF types (280, 190 and 141bp) were significantly more abundant in C. incertus, representing three clusters in Glomus which also named as VT (virtual taxa) 287, 64 and 214, Rhizophagus intraradices (VT 113) and Diversispora sp. (VT 60). While the specific T-RF types, 189 and 279bp, for S. viridis, only existed in Glomus cluster 1 (VT 156), were significantly less abundant in C. incertus. These results indicated that AM fungi might play an important role in the invasion process of C. incertus, which stil remains to be fur-ther investigated.

  6. Especies de hongos formadores de Micorrizas Arbusculares: nuevas citas para la República Argentina Arbuscular mycorrhizal fungal species: new records for Argentina

    Directory of Open Access Journals (Sweden)

    G. Irrazabal

    2005-07-01

    Full Text Available Se investigó la presencia de hongos formadores de micorrizas arbusculares asociados a plantas colectadas en un agroecosistema y en un bosque nativo de tala, en la provincia de Buenos Aires. Las especies que constituyen un nuevo registro para la Argentina son: Scutellospora dipapillosa (Walker & Koske Walker & Sanders y Scutellospora fulgida Koske & Walker halladas en la rizósfera de Triticum aestivum L.; Scutellospora gilmorei (Trappe & Gerd. Walker & Sanders, en la rizósfera de Celtis tala Gill. Ex Planch., Scutia buxifolia Reiss. y plantas herbáceas; Acaulospora delicata Walker, Pfeiffer & Bloss. y Glomus clarum Nicolson & Schenck, halladas en ambos sitios. Estas especies son citadas, descriptas e ilustradas por primera vez para Argentina. Glomus etunicatum Becker & Gerdemann ha sido citada pero no descripta e ilustrada para nuestro país.The presence of arbuscular mycorrhizal fungi associated with plants from an agroecosystem and a native forest, in Buenos Aires province is studied. The species that correspond a new register for Argentina are: Scutellospora dipapillosa (Walker & Koske Walker & Sanders and Scutellospora fulgida Koske & Walker found in the rhizosphere of Triticum aestivum L.; Scutellospora gilmorei (Trappe & Gerd. Walker & Sanders, in the rhizosphere of Celtis tala Gill. Ex Planch., Scutia buxifolia Reiss. and herbaceous plants; Acaulospora delicata Walker, Pfeiffer & Bloss. and Glomus clarum Nicolson & Schenck, occurred in both sites. They are cited, described and illustrated for the first time from Argentina. Glomus etunicatum Becker & Gerdemann was previously cited although it was not described and illustrated from Argentina.

  7. Impact of water regimes on an experimental community of four desert arbuscular mycorrhizal fungal (AMF) species, as affected by the introduction of a non-native AMF species.

    Science.gov (United States)

    Symanczik, Sarah; Courty, Pierre-Emmanuel; Boller, Thomas; Wiemken, Andres; Al-Yahya'ei, Mohamed N

    2015-11-01

    Field studies have revealed the impact of changing water regimes on the structure of arbuscular mycorrhizal fungal (AMF) communities, but it is not known what happens to the abundance of individual AMF species within the community when the water conditions in the rhizosphere change. The behavior of four AMF species isolated from the Arabian desert (Diversispora aurantia, Diversispora omaniana, Septoglomus africanum, and an undescribed Paraglomus species) was investigated when assembled in microcosms containing Sorghum bicolor as host plant, and treated with various water regimes. Furthermore, the impact of invasion of these assemblages by Rhizophagus irregularis, an AMF species widely used in commercial inocula, was studied. The abundance of each AMF species in sorghum roots was measured by determining the transcript numbers of their large ribosomal subunit (rLSU) by real-time PCR, using cDNA and species-specific primers. Plant biomass and length of AMF extraradical hyphae were also measured. The abundance of each AMF species within the sorghum roots was influenced by both the water regime and the introduction of R. irregularis. Under dry conditions, the introduction of R. irregularis reduced the total abundance of all native AMF species in roots and also led to a reduction in the amount of extraradical mycelium, as well as to a partial decrease in plant biomass. The results indicate that both water regime and the introduction of an invasive AMF species can strongly alter the structure of an AMF native assemblage with a consequent impact on the entire symbiotic mycorrhizal relationship.

  8. Diversity of root-associated arbuscular mycorrhizal fungal communities in a rubber tree plantation chronosequence in Northeast Thailand.

    Science.gov (United States)

    Herrmann, Laetitia; Lesueur, Didier; Bräu, Lambert; Davison, John; Jairus, Teele; Robain, Henri; Robin, Agnès; Vasar, Martti; Wiriyakitnateekul, Wanpen; Öpik, Maarja

    2016-11-01

    Rubber tree (Hevea brasiliensis) is of major economic importance in Southeast Asia and for small land holders in Thailand in particular. Due to the high value of latex, plantations are expanding into unsuitable areas, such as the northeast province of Thailand where soil fertility is very low and therefore appropriate management practices are of primary importance. Arbuscular mycorrhizal fungi (AMF) contribute to plant growth through a range of mechanisms and could play a key role in a more sustainable management of the rubber plantations. We described the diversity of AMF associated with rubber tree roots in Northeast Thailand in relation to tree age and soil parameters along a chronosequence of rubber tree plantations. Cassava fields were included for comparison. Rubber tree and cassava roots harbored high diversity of AMF (111 Virtual Taxa, VT), including 20 novel VT. AMF VT richness per sample was consistently high (per site mean 16 to 21 VT per sample) along the chronosequence and was not related to soil properties. The composition of AMF communities differed between cassava and rubber tree plantations and was influenced by soil texture and nutrient content (sand, K, P, Ca). AMF community composition gradually shifted with the age of the trees. Our results suggest that the high diversity of AMF in this region is potentially significant for maintaining high functionality of AMF communities.

  9. Arbuscular mycorrhizal fungal communities along a pedo-hydrological gradient in a Central Amazonian terra firme forest.

    Science.gov (United States)

    de Oliveira Freitas, Rejane; Buscardo, Erika; Nagy, Laszlo; dos Santos Maciel, Alex Bruno; Carrenho, Rosilaine; Luizão, Regina C C

    2014-01-01

    Little attention has been paid to plant mutualistic interactions in the Amazon rainforest, and the general pattern of occurrence and diversity of arbuscular mycorrhizal fungi (AMF) in these ecosystems is largely unknown. This study investigated AMF communities through their spores in soil in a 'terra firme forest' in Central Amazonia. The contribution played by abiotic factors and plant host species identity in regulating the composition, abundance and diversity of such communities along a topographic gradient with different soils and hydrology was also evaluated. Forty-one spore morphotypes were observed with species belonging to the genera Glomus and Acaulospora, representing 44 % of the total taxa. Soil texture and moisture, together with host identity, were predominant factors responsible for shaping AMF communities along the pedo-hydrological gradient. However, the variability within AMF communities was largely associated with shifts in the relative abundance of spores rather than changes in species composition, confirming that common AMF species are widely distributed in plant communities and all plants recruited into the forest are likely to be exposed to the dominant sporulating AMF species.

  10. Arbuscular mycorrhizal fungal communities and soil aggregation as affected by cultivation of various crops during the sugarcane fallow period

    Directory of Open Access Journals (Sweden)

    Priscila Viviane Truber

    2014-04-01

    Full Text Available Management systems involving crop rotation, ground cover species and reduced soil tillage can improve the soil physical and biological properties and reduce degradation. The primary purpose of this study was to assess the effect of various crops grown during the sugarcane fallow period on the production of glomalin and arbuscular mycorrhizal fungi in two Latosols, as well as their influence on soil aggregation. The experiment was conducted on an eutroferric Red Latosol with high-clay texture (680 g clay kg-1 and an acric Red Latosol with clayey texture (440 g kg-1 clay in Jaboticabal (São Paulo State, Brazil. A randomized block design involving five blocks and four crops [soybean (S, soybean/fallow/soybean (SFS, soybean/millet/soybean (SMS and soybean/sunn hemp/soybean (SHS] was used to this end. Soil samples for analysis were collected in June 2011. No significant differences in total glomalin production were detected between the soils after the different crops. However, total external mycelium length was greater in the soils under SMS and SHS. Also, there were differences in easily extractable glomalin, total glomalin and aggregate stability, which were all greater in the eutroferric Red Latosol than in the acric Red Latosol. None of the cover crops planted in the fallow period of sugarcane improved aggregate stability in either Latosol.

  11. 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.

  12. Increases in soil aggregation following phosphorus additions in a tropical premontane forest are not driven by root and arbuscular mycorrhizal fungal abundances

    Science.gov (United States)

    Camenzind, Tessa; Papathanasiou, Helena; Foerster, Antje; Dietrich, Karla; Hertel, Dietrich; Homeier, Juergen; Oelmann, Yvonne; Olsson, Pål Axel; Suárez, Juan; Rillig, Matthias

    2015-12-01

    Tropical ecosystems have an important role in global change scenarios, in part because they serve as a large terrestrial carbon pool. Carbon protection is mediated by soil aggregation processes, whereby biotic and abiotic factors influence the formation and stability of aggregates. Nutrient additions may affect soil structure indirectly by simultaneous shifts in biotic factors, mainly roots and fungal hyphae, but also via impacts on abiotic soil properties. Here, we tested the hypothesis that soil aggregation will be affected by nutrient additions primarily via changes in arbuscular mycorrhizal fungal (AMF) hyphae and root length in a pristine tropical forest system. Therefore, the percentage of water-stable macroaggregates (> 250µm) (WSA) and the soil mean weight diameter (MWD) was analyzed, as well as nutrient contents, pH, root length and AMF abundance. Phosphorus additions significantly increased the amount of WSA, which was consistent across two different sampling times. Despite a positive effect of phosphorus additions on extraradical AMF biomass, no relationship between WSA and extra-radical AMF nor roots was revealed by regression analyses, contrary to the proposed hypothesis. These findings emphasize the importance of analyzing soil structure in understudied tropical systems, since it might be affected by increasing nutrient deposition expected in the future.

  13. Increases in soil aggregation following phosphorus additions in a tropical premontane forest are not driven by root and arbuscular mycorrhizal fungal abundances

    Directory of Open Access Journals (Sweden)

    Tessa eCamenzind

    2016-01-01

    Full Text Available Tropical ecosystems have an important role in global change scenarios, in part because they serve as a large terrestrial carbon pool. Carbon protection is mediated by soil aggregation processes, whereby biotic and abiotic factors influence the formation and stability of aggregates. Nutrient additions may affect soil structure indirectly by simultaneous shifts in biotic factors, mainly roots and fungal hyphae, but also via impacts on abiotic soil properties. Here, we tested the hypothesis that soil aggregation will be affected by nutrient additions primarily via changes in arbuscular mycorrhizal fungal (AMF hyphae and root length in a pristine tropical forest system. Therefore, the percentage of water-stable macroaggregates (> 250µm (WSA and the soil mean weight diameter (MWD was analyzed, as well as nutrient contents, pH, root length and AMF abundance. Phosphorus additions significantly increased the amount of WSA, which was consistent across two different sampling times. Despite a positive effect of phosphorus additions on extraradical AMF biomass, no relationship between WSA and extra-radical AMF nor roots was revealed by regression analyses, contrary to the proposed hypothesis. These findings emphasize the importance of analyzing soil structure in understudied tropical systems, since it might be affected by increasing nutrient deposition expected in the future.

  14. Long-term preservation of Arbuscular mycorrhizal fungi

    OpenAIRE

    Lalaymia, Ismahen

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts, forming associations with most existing terrestrial plants. The plants obtain inorganic nutrients (e.g. N, P) via their fungal partners in exchange of which they provide the fungi with carbon compounds. AMF improve plant growth, health and productivity and as such, represent key organisms in agro-ecosystems. Currently, AMF diversity is maintained via continuous culture; in vivo on trap plants under greenhouse facilities, and in v...

  15. Wheat protection against powdery mildew by arbuscular mycorrhizal fungi : mechanisms and optimization

    OpenAIRE

    Mustafa, Ghalia

    2015-01-01

    The use of arbuscular mycorrhizal fungi (AMF) could be an innovative alternative to chemicals against fungal plant diseases. Our work aimed at studying the possible protective effect of arbuscular mycorrhization in the bread wheat (Triticum aestivum L.) against Blumeria graminis f. sp. tritici (Bgt), a biotrophic fungi responsible of wheat powdery mildew, a disease affecting the aerial plant organs. Wheat mycorrhizal inoculation by Funneliformis mosseae (Fm), under controlled and optimized co...

  16. Arbuscular mycorrhizal fungal diversity, root colonization, and soil alkaline phosphatase activity in response to maize-wheat rotation and no-tillage in North China.

    Science.gov (United States)

    Hu, Junli; Yang, Anna; Zhu, Anning; Wang, Junhua; Dai, Jue; Wong, Ming Hung; Lin, Xiangui

    2015-07-01

    Monitoring the effects of no-tillage (NT) in comparison with conventional tillage (CT) on soil microbes could improve our understanding of soil biochemical processes and thus help us to develop sound management strategies. The objective of this study was to compare the species composition and ecological function of soil arbuscular mycorrhizal (AM) fungi during the growth and rotation of crops under NT and CT. From late June 2009 to early June 2010, 32 topsoil (0-15 cm) samples from four individual plots per treatment (CT and NT) were collected at both the jointing and maturation stages of maize (Zea mays L.) and wheat (Triticum aestivum L.) from a long-term experimental field that was established in an Aquic Inceptisol in North China in June 2006. The AM fungal spores were isolated and identified and then used to calculate species diversity indices, including the Shannon- Wiener index (H'), Evenness (E), and Simpson's index (D). The root mycorrhizal colonization and soil alkaline phosphatase activity were also determined. A total of 34 species of AM fungi within nine genera were recorded. Compared with NT, CT negatively affected the soil AM fungal community at the maize sowing stage, leading to decreases in the average diversity indices (from 2.12, 0.79, and 0.82 to 1.79, 0.72, and 0.74 for H', E, and D, respectively), root mycorrhizal colonization (from 28% to 20%), soil alkaline phosphatase activity (from 0.24 to 0.19 mg/g/24 h) and available phosphorus concentration (from 17.4 to 10.5 mg/kg) at the maize jointing stage. However, reductions in diversity indices of H', E, and D were restored to 2.20, 0.81, and 0.84, respectively, at the maize maturation stage. CT should affect the community again at the wheat sowing stage; however, a similar restoration in the species diversity of AM fungi was completed before the wheat jointing stage, and the highest Jaccard index (0.800) for similarity in the species composition of soil AM fungi between CT and NT was recorded at

  17. Isolation of Inositol Hexaphosphate (IHP)-Degrading Bacteria from Arbuscular Mycorrhizal Fungal Hyphal Compartments Using a Modified Baiting Method Involving Alginate Beads Containing IHP

    Science.gov (United States)

    Hara, Shintaro; Saito, Masanori

    2016-01-01

    Phytate (inositol hexaphosphate; IHP)-degrading microbes have been suggested to contribute to arbuscular mycorrhizal fungi (AMF)-mediated P transfer from IHP to plants; however, no IHP degrader involved in AMF-mediated P transfer has been isolated to date. We herein report the isolation of IHP-degrading bacteria using a modified baiting method. We applied alginate beads as carriers of IHP powder, and used them as recoverable IHP in the AM fungal compartment of plant cultivation experiments. P transfer from IHP in alginate beads via AMF was confirmed, and extracted DNA from alginate beads was analyzed by denaturing gradient gel electrophoresis targeting the 16S rRNA gene and a clone library method for the beta-propeller phytase (BPP) gene. The diversities of the 16S rRNA and BPP genes of microbes growing on IHP beads were simple and those of Sphingomonas spp. and Caulobacter spp. dominated. A total of 187 IHP-utilizing bacteria were isolated and identified, and they were consistent with the results of DNA analysis. Furthermore, some isolated Sphingomonas spp. and Caulobacter sp. showed IHP-degrading activity. Therefore, we successfully isolated dominant IHP-degrading bacteria from IHP in an AMF hyphal compartment. These strains may contribute to P transfer from IHP via AMF. PMID:27383681

  18. Rapid response of arbuscular mycorrhizal fungal communities to short-term fertilization in an alpine grassland on the Qinghai-Tibet Plateau

    Directory of Open Access Journals (Sweden)

    Xingjia Xiang

    2016-07-01

    Full Text Available Background: The Qinghai-Tibet Plateau (QTP is home to the vast grassland in China. The QTP grassland ecosystem has been seriously degraded by human land use practices and climate change. Fertilization is used in this region to increase vegetation yields for grazers. The impact of long-term fertilization on plant and microbial communities has been studied extensively. However, the influence of short-term fertilization on arbuscular mycorrhizal fungal (AMF communities in the QTP is largely unknown, despite their important functional role in grassland ecosystems. Methods: We investigated AMF community responses to three years of N and/or P addition at an experimental field site on the QTP, using the Illumina MiSeq platform (PE 300. Results: Fertilization resulted in a dramatic shift in AMF community composition and NP addition significantly increased AMF species richness and phylogenetic diversity. Aboveground biomass, available phosphorus, and NO3− were significantly correlated with changes in AMF community structure. Changes in these factors were driven by fertilization treatments. Thus, fertilization had a large impact on AMF communities, mediated by changes in aboveground productivity and soil chemistry. Discussion: Prior work has shown how plants often lower their reliance on AMF symbioses following fertilization, leading to decrease AMF abundance and diversity. However, our study reports a rise in AMF diversity with fertilization treatment. Because AMF can provide stress tolerance to their hosts, we suggest that extreme weather on the QTP may help drive a positive relationship between fertilizer amendment and AMF diversity.

  19. The composition of arbuscular mycorrhizal fungal communities in the roots of a ruderal forb is not related to the forest fragmentation process.

    Science.gov (United States)

    Grilli, Gabriel; Urcelay, Carlos; Galetto, Leonardo; Davison, John; Vasar, Martti; Saks, Ülle; Jairus, Teele; Öpik, Maarja

    2015-08-01

    Land-use changes and forest fragmentation have strong impact on biodiversity. However, little is known about the influence of new landscape configurations on arbuscular mycorrhizal fungal (AMF) community composition. We used 454 pyrosequencing to assess AMF diversity in plant roots from a fragmented forest. We detected 59 virtual taxa (VT; phylogenetically defined operational taxonomic units) of AMF - including 10 new VT - in the roots of Euphorbia acerensis. AMF communities were mainly composed of members of family Glomeraceae and were similar throughout the fragmented landscape, despite variation in forest fragment size (i.e. small, medium and large) and isolation (i.e. varying pairwise distances). AMF communities in forest fragments were phylogenetically clustered compared with the global, but not regional and local AMF taxon pools. This indicates that non-random community assembly processes possibly related to dispersal limitation at a large scale, rather than habitat filtering or biotic interactions, may be important in structuring the AMF communities. In this system, forest fragmentation did not appear to influence AMF community composition in the roots of the ruderal plant. Whether this is true for AMF communities in soil and the roots of other ecological groups of host plants or in other habitats deserves further study.

  20. Arbuscular mycorrhizal fungi reveal distinct patterns of anastomosis formation and hyphal healing mechanisms between different phylogenic groups

    NARCIS (Netherlands)

    De Souza, F.A.; Fernández, F.; Delmas, N.S.; Declerck, S.

    2005-01-01

    The significance of anastomosis formation and the hyphal healing mechanism (HHM) for functionality and integrity of the arbuscular mycorrhizal (AM) fungal mycelial network remains poorly documented. Four Glomeraceae and three Gigasporaceae were cultured monoxenically. Anastomosis formation was asses

  1. Breakdown and delayed cospeciation in the arbuscular mycorrhizal mutualism.

    Science.gov (United States)

    Merckx, Vincent; Bidartondo, Martin I

    2008-05-01

    The ancient arbuscular mycorrhizal association between the vast majority of plants and the fungal phylum Glomeromycota is a dominant nutritional mutualism worldwide. In the mycorrhizal mutualism, plants exchange photosynthesized carbohydrates for mineral nutrients acquired by fungi from the soil. This widespread cooperative arrangement is broken by 'cheater' plant species that lack the ability to photosynthesize and thus become dependent upon three-partite linkages (cheater-fungus-photosynthetic plant). Using the first fine-level coevolutionary analysis of mycorrhizas, we show that extreme fidelity towards fungi has led cheater plants to lengthy evolutionary codiversification. Remarkably, the plants' evolutionary history closely mirrors that of their considerably older mycorrhizal fungi. This demonstrates that one of the most diffuse mutualistic networks is vulnerable to the emergence, persistence and speciation of highly specific cheaters.

  2. Arbuscular Mycorrhizal Fungal Communities in the Roots of Maize Lines Contrasting for Al Tolerance Grown in Limed and Non-Limed Brazilian Oxisoil.

    Science.gov (United States)

    Gomes, Eliane A; Oliveira, Christiane A; Lana, Ubiraci G P; Noda, Roberto W; Marriel, Ivanildo E; de Souza, Francisco A

    2015-07-01

    Aluminum (Al) toxicity is one of the greatest limitations to agriculture in acid soils, particularly in tropical regions. Arbuscular mycorrhizal fungi (AMF) can supply plants with nutrients and give protection against Al toxicity. The aim of this work was to evaluate the effects of soil liming (i.e., reducing Al saturation) on the AMF community composition and structure in the roots of maize lines contrasting for Al tolerance. To this end, we constructed four 18S rDNA cloning libraries from L3 (Al tolerant) and L22 (Al sensitive) maize lines grown in limed and non-limed soils. A total of 790 clones were sequenced, 69% belonging to the Glomeromycota phylum. The remaining sequences were from Ascomycota, which were more prominent in the limed soil, mainly in the L3 line. The most abundant AM fungal clones were related to the family Glomeraceae represented by the genera uncultured Glomus followed by Rhizophagus and Funneliformis. However, the most abundant operational taxonomic units with 27% of the Glomeromycota clones was affiliated to genus Racocetra. This genus was present in all the four libraries, but it was predominant in the non-limed soils, suggesting that Racocetra is tolerant to Al toxicity. Similarly, Acaulospora and Rhizophagus were also present mostly in both lines in non-limed soils. The community richness of AMF in the non-limed soils was higher than the limed soil for both lines. The results suggest that the soil Al saturation was the parameter that mostly influences the AMF species composition in the soils in this study.

  3. Changes in Arbuscular Mycorrhizal Fungal Abundance and Community Structure in Response to the Long-Term Manipulation of Inorganic Nutrients in a Lowland Tropical Forest

    Science.gov (United States)

    Sheldrake, Merlin; Rosenstock, Nicholas; Tanner, Ed

    2014-05-01

    The arbuscular mycorrhizal (AM) symbiosis is considered primarily mutualistic. In exchange for up to 30% of plants' total photosynthate, AM provide improved access to mineral nutrients. While there is evidence that AM fungi provide nitrogen, potassium and other nutrients to their host plants, most research has focused on their effect on plant phosphorus uptake. Pot experiments have shown, and field experiments have provided further support, that nutrient availability (primarily P, but also N) is inversely correlated with mycorrhizal colonization, indicating plant control over carbon losses to AM fungi. Yet pot experiments have also shown that some fungal species are more mutualistic than others and that AM colonization may cause decreased plant growth, suggesting that plant control is not absolute. AMF communities are diverse, and it is poorly understood how factors such as adaptation to local soil environment, fungal-plant compatibility, and plant nutrient status combine to shape AMF community structure. We conducted a study to examine the relative effects of N, P, and K addition on the AMF community in a plant species rich tropical forest, given the long-held belief that AMF are primarily involved in plant P uptake, particularly on weathered tropical soils. Our study site is the Barro Colorado Nature Monument in Panama. It is a 13 year-old factorial N, P, and K addition experiment (40 m x 40m plots; n=4) in an AMF dominated, old (>200 yr), secondary, tropical forest. Previous research has shown co-limitation by N, P, and K, but the strongest plant growth responses were obtained with K additions. We analyzed the AMF community using 454 pyrosequencing of the ribosomal small subunit (SSU) on both soils and the roots of the 6 dominant AMF tree species. Additionally, we used the AMF-specific neutral lipid fatty acid (NLFA) biomarker as a measure of AMF biomass. Both AMF biomass and community structure were altered by nutrient additions. AMF biomass in soil was reduced

  4. The Effects of Arbuscular Mycorrhizal Fungal Inoculation and Mulch of Contrasting Chemical Composition on the Yield of Cassava under Humid Tropical Conditions

    Directory of Open Access Journals (Sweden)

    Iniobong E. Okon

    2010-01-01

    Full Text Available The influence of arbuscular mycorrhizal fungus (AMF, Glomus deserticola, and leaf mulch from Gliricidia sepium and Senna siamea on the yield of cassava (Manihot esculenta in a degraded alfisol of southwestern Nigeria was investigated. Inoculation in conjunction with mulching increased cassava tuber yield by 40–278% over the control. The highest yield was obtained with G. sepium and S. siamea mulch applied together in equal proportions. The results are explained in the light of the growth-enhancing effects of AMF, encouraged by the ameliorating effects of mulch on the soil structure and nutrient contents.

  5. Mixed arbuscular mycorrhizal (AM) fungal application to improve growth and arsenic accumulation of Pteris vittata (As hyperaccumulator) grown in As-contaminated soil.

    Science.gov (United States)

    Leung, H M; Leung, A O W; Ye, Z H; Cheung, K C; Yung, K K L

    2013-08-01

    A greenhouse pot experiment was conducted to study the effects of three types of single inoculum [indigenous mycorrhizas (IM) isolated from As mine, Glomus mosseae (GM) and Glomus intraradices (GI)] and two types of mixed inoculum (mixed with IM and either GM or GI) on the growth response of Pteris vittata (hyperaccumulator) and Cynodon dactylon (non-hyperaccumulator) at three levels of As concentrations (0, 100 and 200mgkg(-1)). Both mycorrhizal plants exhibited significantly higher biomass, and N and P accumulation in its tissue than the control. Among the mycorrhizal inoculum, the mixed inoculum IM/GM promoted substantially higher mycorrhizal colonization and arsenate reductase activity in P. vittata than C. dactylon, among all As levels. The portion of Paris arbuscular mycorrhizal structure (observed in colonized roots) together with the highest As translocation factor of 10.2 in P. vittata inoculated with IM/GM was also noted. It was deduced that IM/GM inoculum may be the best choice for field inoculation at any contaminated lands as the inoculum exhibited better adaptation to variable environmental conditions and hence benefited the host plants.

  6. Comparison of communities of arbuscular mycorrhizal fungi in roots of two Viola species

    DEFF Research Database (Denmark)

    Opik, M; Moora, Mari; Liira, Jaan;

    2006-01-01

    The composition of arbuscular mycorrhizal (AM) fungal communities in roots of rare Viola elatior and common V. mirabilis was investigated using PCR with primers specific for Glomus and common was investigated using PCR with primers specific for group A, followed by single-stranded conformation po...

  7. 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.

  8. Calcareous impact on arbuscular mycorrhizal fungus development and on lipid peroxidation in monoxenic roots.

    Science.gov (United States)

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

    2011-12-01

    The present work underlined the negative effects of increasing CaCO(3) concentrations (5, 10 and 20 mM) both on the chicory root growth and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare development in monoxenic system. CaCO(3) was found to reduce drastically the main stages of G. irregulare life cycle (spore germination, germinative hyphae elongation, root colonization, extraradical hyphae development and sporulation) but not to inhibit it completely. The root colonization drop was confirmed by the decrease in the arbuscular mycorrhizal fungal marker C16:1ω5 amounts in the mycorrhizal chicory roots grown in the presence of CaCO(3). Oxidative damage evaluated by lipid peroxidation increase measured by (i) malondialdehyde (MDA) production and (ii) the antioxidant enzyme peroxidase (POD) activities, was highlighted in chicory roots grown in the presence of CaCO(3). However, MDA formation was significantly higher in non-mycorrhizal roots as compared to mycorrhizal ones. This study pointed out the ability of arbuscular mycorrhizal symbiosis to enhance plant tolerance to high levels of CaCO(3) by preventing lipid peroxidation and so less cell membrane damage.

  9. Interactions between plants and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Hata, Shingo; Kobae, Yoshihiro; Banba, Mari

    2010-01-01

    Arbuscular mycorrhizal (AM) fungi inhabit the root cortical cells of most plants and obtain photosynthates from the host plants while they transfer mineral nutrients from the soil to the hosts. In this review, we first summarize recent progress regarding signal molecules involved in the recognition of each symbiont, the signaling pathways in the host plants, and the characteristics of AM-inducible nutrient transporters, which were elucidated mainly using model legumes. Then, we summarize studies on the colonization by AM fungi of lower plants and of the roots of major crops. There are not only "AM-responsive" crops like maize, sorghum, and soybean but also "AM-nonresponsive" ones like wheat, barley, and rice. Finally, we mention the worldwide problems of limited and biased agricultural resources and discuss future directions as to how we can make use of AM symbiosis for improving crop production and establishing sustainable agriculture.

  10. 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.).

  11. The effect of sulfur on the composition of arbuscular mycorrhizal fungal communities during the pod-setting stage of different soybean cultivars.

    Science.gov (United States)

    Jie, Weiguang; Cai, Baiyan; Zhang, Yong; Li, Jin; Ge, Jingping

    2012-11-01

    This study sought to investigate the effect of sulfur levels on changes in the fungal community composition of arbuscular mycorrhizae (AM) at the pod-setting stage and the relationship between the amount of applied sulfur and AM fungal diversity in different soybean cultivars. The objective of the research was to determine the optimal sulfur application level for different soybean cultivars and to improve soybean yield and quality from the perspective of AM fungal diversity. Three soybean cultivars, Heinong 44, Heinong 48, and Heinong 37, were selected as study materials. In addition to 0.033 g each of N, P(2)O(5) and K(2)O per kg of soil, 0, 0.02, 0.04, or 0.06 g of elemental sulfur was applied to each kg of soil for the four treatment groups, S1, S2, S3, and S4, respectively. The AM fungal community structure was analyzed in the soil and root of different soybean cultivars using the PCR-DGGE technology. The results indicated a significant effect of sulfur on the AM fungal community structure in the roots and rhizospheric soil of different soybean cultivars. The three soybean cultivars in group S2 exhibited the highest diversity in AM fungus. Significant changes in the dominant fungal species were observed in the DGGE fingerprints of each sample, and Glomus, Funneliformis, Rhizophagus, and Claroideoglomus fungi were the dominant species of AM fungus in the roots and soil of soybean. The application of an appropriate amount of sulfur improved the diversity of AM fungi in roots and rhizospheric soil of different soybean cultivars.

  12. Epiparasitic plants specialized on arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Bidartondo, Martin I; Redecker, Dirk; Hijri, Isabelle; Wiemken, Andres; Bruns, Thomas D; Domínguez, Laura; Sérsic, Alicia; Leake, Jonathan R; Read, David J

    2002-09-26

    Over 400 non-photosynthetic species from 10 families of vascular plants obtain their carbon from fungi and are thus defined as myco-heterotrophs. Many of these plants are epiparasitic on green plants from which they obtain carbon by 'cheating' shared mycorrhizal fungi. Epiparasitic plants examined to date depend on ectomycorrhizal fungi for carbon transfer and exhibit exceptional specificity for these fungi, but for most myco-heterotrophs neither the identity of the fungi nor the sources of their carbon are known. Because many myco-heterotrophs grow in forests dominated by plants associated with arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota), we proposed that epiparasitism would occur also between plants linked by AMF. On a global scale AMF form the most widespread mycorrhizae, thus the ability of plants to cheat this symbiosis would be highly significant. We analysed mycorrhizae from three populations of Arachnitis uniflora (Corsiaceae, Monocotyledonae), five Voyria species and one Voyriella species (Gentianaceae, Dicotyledonae), and neighbouring green plants. Here we show that non-photosynthetic plants associate with AMF and can display the characteristic specificity of epiparasites. This suggests that AMF mediate significant inter-plant carbon transfer in nature.

  13. Occurrence and Structure of Arbuscular Mycorrhizal Fungal Communities in Cassava after Cultivation of Cover Crops as Observed by the “PCR-DGGE” Technique

    Directory of Open Access Journals (Sweden)

    Elaine dos Santos Heberle

    2015-10-01

    Full Text Available ABSTRACT Cassava (Manihot esculenta Crantz is a highly mycotrophic crop, and prior soil cover may affect the density of arbuscular mycorrhizal fungi (AMFs, as well as the composition of the AMFs community in the soil. The aim of this study was to evaluate the occurrence and the structure of AMFs communities in cassava grown after different cover crops, and the effect of the cover crop on mineral nutrition and cassava yield under an organic farming system. The occurrence and structure of the AMFs community was evaluated through polymerase chain reaction (PCR and denaturing gradient gel electrophoresis (DGGE. A randomized block experimental design was used with four replications. Six different cover crop management systems before cassava were evaluated: black oats, vetch, oilseed radish, intercropped oats + vetch, intercropped oats + vetch + oilseed radish, plus a control (fallow treatment mowed every 15 days. Oats as a single crop or oats intercropped with vetch or with oilseed radish increased AMFs inoculum potential in soil with a low number of propagules, thus benefiting mycorrhizal colonization of cassava root. The treatments did not affect the structure of AMFs communities in the soil since the AMFs communities were similar in cassava roots in succession to different cover crops. AMFs colonization was high despite high P availability in the soil. The cassava crop yield was above the regional average, and P levels in the leaves were adequate, regardless of which cover crop treatments were used. One cover crop cycle prior to the cassava crop was not enough to observe a significant response in variables, P in plant tissue, crop yield, and occurrence and structure of AMFs communities in the soil. In the cassava roots in succession, the plant developmental stage affected the groupings of the structure of the AMF community.

  14. Land-use intensity and host plant simultaneously shape the composition of arbuscular mycorrhizal fungal communities in a Mediterranean drained peatland.

    Science.gov (United States)

    Ciccolini, Valentina; Ercoli, Laura; Davison, John; Vasar, Martti; Öpik, Maarja; Pellegrino, Elisa

    2016-12-01

    Land-use change is known to be a major threat to biodiversity and ecosystem services in Mediterranean areas. However, the potential for different host plants to modulate the effect of land-use intensification on community composition of arbuscular mycorrhizal fungi (AMF) is still poorly understood. To test the hypothesis that low land-use intensity promotes AMF diversity at different taxonomic scales and to determine whether any response is dependent upon host plant species identity, we characterised AMF communities in the roots of 10 plant species across four land use types of differing intensity in a Mediterranean peatland system. AMF were identified using 454 pyrosequencing. This revealed an overall low level of AMF richness in the peaty soils; lowest AMF richness in the intense cropping system at both virtual taxa and family level; strong modulation by the host plant of the impact of land-use intensification on AMF communities at the virtual taxa level; and a significant effect of land-use intensification on AMF communities at the family level. These findings have implications for understanding ecosystem stability and productivity and should be considered when developing soil-improvement strategies in fragile ecosystems, such as Mediterranean peatlands.

  15. The composition of arbuscular mycorrhizal fungal communities differs among the roots, spores and extraradical mycelia associated with five Mediterranean plant species.

    Science.gov (United States)

    Varela-Cervero, Sara; Vasar, Martti; Davison, John; Barea, José Miguel; Öpik, Maarja; Azcón-Aguilar, Concepción

    2015-08-01

    Arbuscular mycorrhizal fungi (AMF) are essential constituents of most terrestrial ecosystems. AMF species differ in terms of propagation strategies and the major propagules they form. This study compared the AMF community composition of different propagule fractions - colonized roots, spores and extraradical mycelium (ERM) - associated with five Mediterranean plant species in Sierra de Baza Natural Park (Granada, Spain). AMF were identified using 454 pyrosequencing of the SSU rRNA gene. A total of 96 AMF phylogroups [virtual taxa (VT)] were detected in the study site, including 31 novel VT. After per-sample sequencing depth standardization, 71 VT were recorded from plant roots, and 47 from each of the spore and ERM fractions. AMF communities differed significantly among the propagule fractions, and the root-colonizing fraction differed among host plant species. Indicator VT were detected for the root (13 Glomus VT), spore (Paraglomus VT281, VT336, Pacispora VT284) and ERM (Diversispora VT62) fractions. This study provides detailed evidence from a natural system that AMF taxa are differentially allocated among soil mycelium, soil spores and colonized root propagules. This has important implications for interpreting AMF diversity surveys and designing applications of AMF in vegetation restoration.

  16. 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.

  17. 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.

  18. Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis

    OpenAIRE

    2013-01-01

    The arbuscular mycorrhizal symbiosis between fungi of the Glomeromycota phylum and plants involves more than two-thirds of all known plant species, including important crop species. This mutualistic symbiosis, involving one of the oldest fungal lineages, is arguably the most ecologically and agriculturally important symbiosis in terrestrial ecosystems. The Glomeromycota are unique in that their spores and coenocytic hyphae contain hundreds of nuclei in a common cytoplasm, which raises importa...

  19. Inoculation of drought-stressed strawberry with a mixed inoculum of two arbuscular mycorrhizal fungi: effects on population dynamics of fungal species in roots and consequential plant tolerance to water deficiency.

    Science.gov (United States)

    Boyer, Louisa Robinson; Brain, Philip; Xu, Xiang-Ming; Jeffries, Peter

    2015-04-01

    The effect of inoculation with two arbuscular mycorrhizal fungi (AMF) on growth and drought tolerance of cultivated strawberry (Fragaria × ananassa) was studied. Three treatments (a single treatment either of Funneliformis mosseae BEG25, Funneliformis geosporus BEG11 or a 50:50 mixed inoculation treatment of both species) were compared to uninoculated plants. Species-specific primers for qPCR quantification of F. geosporus and F. mosseae DNA were developed to quantify the relative abundance of each fungus in roots of strawberry under different conditions of water stress. Co-occupation of the same root by both species was shown to commonly occur, but their relative abundance varied with water stress (reduced irrigation of up to 40%). Greater root colonisation was observed microscopically under water stress, but this increased colonisation was often accompanied with decreased amounts of fungal DNA in the root. F. mosseae tended to become more abundant under water stress relative to F. geosporus. There was significant correlation in the fungal colonisation measurements from the microscopic and qPCR methods under some conditions, but the nature of this relationship varied greatly with AMF inoculum and abiotic conditions. Single-species inoculation treatments gave similar benefits to the host to the mixed inoculation treatment regardless of irrigation regime; here, amount of colonisation was of greater importance than functional diversity. The addition of AMF inocula to plants subjected to reduced irrigation restored plant growth to the same or higher values as the non-mycorrhizal, fully-watered plants. The water use efficiency of plants was greater under the regulated deficit irrigation (RDI) regime and in AMF-inoculated plants, but there were no significant differences between plants inoculated with the single or combined inoculum. This study demonstrated that the increase in plant growth was directly influenced by an increase in root colonisation by AMF when

  20. Comparison of communities of arbuscular mycorrhizal fungi in roots of two Viola species

    DEFF Research Database (Denmark)

    Opik, M; Moora, Mari; Liira, Jaan

    2006-01-01

    The composition of arbuscular mycorrhizal (AM) fungal communities in roots of rare Viola elatior and common V. mirabilis was investigated using PCR with primers specific for Glomus and common was investigated using PCR with primers specific for group A, followed by single-stranded conformation...... polymorphism analysis. Twelve AM fungal sequence types were identified, ten of them from both plant species. On average 3.8/7.5 sequence types were detected per 1 cm-long root fragment/per plant. The frequency of individual sequence types was higher and AM fungal community composition less variable in roots...

  1. Signaling events during initiation of arbuscular mycorrhizal symbiosis

    Institute of Scientific and Technical Information of China (English)

    Alexa M. Schmitz; Maria J. Harrison

    2014-01-01

    Under nutrient-limiting conditions, plants wil 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 cellwal s. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is stil 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.

  2. Impacts of fertilization regimes on arbuscular mycorrhizal fungal (AMF community composition were correlated with organic matter composition in maize rhizosphere soil

    Directory of Open Access Journals (Sweden)

    Chen Zhu

    2016-11-01

    Full Text Available The understanding of the response of arbuscular mycorrhizal fungi (AMF community composition to fertilization is of great significance in sustainable agriculture. However, how fertilization influences AMF diversity and composition is not well established yet. A field experiment located in northeast China in typical black soil (Chernozem was conducted and high-throughput sequencing approach was used to investigate the effects of different fertilizations on the variation of AMF community in the rhizosphere soil of maize crop. The results showed that AMF diversity in the maize rhizosphere was significantly altered by different fertilization regimes. As revealed by redundancy analysis, the application of organic manure was the most important factor impacting AMF community composition between samples with and without organic manure, followed by N fertilizer and P fertilizer inputs. Moreover, the organic matter composition in the rhizosphere, determined by GC-MS, was significantly altered by the organic manure amendment. Many of the chemical components displayed significant relationships with the AMF community composition according to the Mantel test, among those, 2-ethylnaphthalene explained the highest percentage (54.2% of the variation. The relative contents of 2-ethylnaphthalene and 2, 6, 10-trimethyltetradecane had a negative correlation with Glomus relative abundance, while the relative content of 3-methylbiphenyl displayed a positive correlation with Rhizophagus. The co-occurrence patterns in treatments with and without organic manure amendment were analysed, and more hubs were detected in the network of soils with organic manure amendment. Additionally, three OTUs belonging to Glomerales were identified as hubs in all treatments, indicating these OTUs likely occupied broad ecological niches and were always active for mediating AMF species interaction in the maize rhizosphere. Taken together, impacts of fertilization regimes on AMF community

  3. 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 transg

  4. Caracterização fenotípica e molecular de esporos de fungos micorrízicos arbusculares mantidos em banco de germoplasma Phenotypic and molecular characterization of arbuscular mycorrhizal fungal spores from cultures maintained in germplasm collection

    Directory of Open Access Journals (Sweden)

    Cândido Barreto de Novais

    2010-08-01

    Full Text Available O objetivo deste trabalho foi caracterizar fenotípica e genotipicamente isolados de espécies de fungos micorrízicos arbusculares (FMA mantidos em cultura pura e avaliar a aplicabilidade da técnica PCR-DGGE desenvolvida para Gigaspora, na identificação molecular de espécies de FMA pertencentes a outros gêneros. A caracterização fenotípica das espécies foi realizada de acordo com critérios morfológicos, descritos pela taxonomia, e com uso de descrições originais das espécies presentes na literatura especializada. A análise genotípica foi feita com base na discriminação específica da região V9 do 18S rDNA, que permitiu a diferenciação das espécies e não revelou qualquer diferença entre os isolados geográficos de Glomus clarum, e entre os de Glomus etunicatum. Isto indica a aplicabilidade da técnica para a avaliação da pureza genética e discriminação de espécies de FMA.The objective of this work was to characterize phenotypically and genotypically isolates of arbuscular mycorrhizal fungi (AMF maintained in pure culture and to evaluate the applicability of PCR-DGGE analysis, developed for Gigaspora, for molecular identification of AMF species belonging to other genres. The species phenotypic characterization was done according to morphological criteria, as described by taxonomy, and according to original descriptions of species published in the specialized literature. The genotypic analysis was made through specific discrimination of the V9 region in the 18S rDNA, which allowed the distinction of species and showed no difference among geographical isolates of Glomus clarum, and among those of Glomus etunicatum. This indicates the applicability of this technique for assessment of genetic purity and discrimination of AMF species.

  5. Uptake of Organic Phosphorus by Arbuscular Mycorrhizal Red Clover

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The capacities of two arbuscular mycorrhizal (AM) fungi, Glomus mosseae and Glomus versiforme, to mineralize added organic P were studied in a sterilized calcareous soil. Mycorrhizal (inoculated with either of the AM fungi) and non-mycorrhizal red clover (Trifolium pratense L.) plants were grown for eight weeks in pots with upper root, central hyphal and lower soil compartments. The hyphal and soil compartments received either organic P (as Na-phytate) or inorganic P (as KH2PO4) at the rate of 50 mg P kg-1. No P was added to the root compartments. Control pots received no added P. Yields were higher in mycorrhizal than in non-mycorrhizal clover. Mycorrhizal inoculation doubled shoot P concentration and more than doubled total P uptake of plants in P-amended soil, irrespective of the form of applied P. The mycorrhizal contribution to inorganic P uptake was 80% or 76% in plants inoculated with G. mosseae or G. versiforme, respectively.Corresponding values were 74% and 82% when Na-phytate was applied. In the root compartments of the mycorrhizal treatments, the proportion of root length infected, hyphal length density and phosphatase activity were all higher when organic P was applied than when inorganic P was added.

  6. 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.

  7. Septoglomus fuscum and S. furcatum, two new species of arbuscular mycorrhizal fungi (Glomeromycota)

    DEFF Research Database (Denmark)

    Blaszkowski, Janusz; Chwat, Gerad; Kovacs, Gábor M;

    2013-01-01

    Two new arbuscular mycorrhizal fungal species, (Glomeromycota) Septoglomus fuscum and S. furcatum, are described and illustrated. Spores of S. fuscum usually occur in loose hypogeous clusters, rarely singly in soil or inside roots, and S. furcatum forms only single spores in soil. Spores of S. fu...... as host plant, S. fuscum and S. furcatum formed arbuscular mycorrhizae. Phylogenetic analyses of the SSU, ITS and LSU nrDNA sequences placed the two new species in genus Septoglomus and both new taxa were separated from described Septoglomus species.......Two new arbuscular mycorrhizal fungal species, (Glomeromycota) Septoglomus fuscum and S. furcatum, are described and illustrated. Spores of S. fuscum usually occur in loose hypogeous clusters, rarely singly in soil or inside roots, and S. furcatum forms only single spores in soil. Spores of S......’s reagent. In the field, S. fuscum was associated with roots of Arctotheca populifolia colonizing maritime dunes located near Strand in South Africa and S. furcatum was associated with Cordia oncocalyx growing in a dry forest in the Ceará State, Brazil. In single-species cultures with Plantago lanceolata...

  8. Arbuscular mycorrhizal and dark septate endophyte associations of medicinal plants

    OpenAIRE

    Szymon Zubek; Janusz Błaszkowski; Piotr Mleczko

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) and dark septate endophyte (DSE) associations were studied in 36 medicinal plant species from 33 genera and 17 families, collected from the Botanical Garden of the Jagiellonian University in Kraków. Arbuscular mycorrhiza (AM) was found in 34 species (94%); 26 were of the Arum-type, 4 – Paris and 4 taxa revealed intermediate morpho­logy. The abundance of AMF hyphae in roots varied with particular species, ranging from 2.5% (Helianthus tuberosus) to 77.9% (Con...

  9. Arbuscular mycorrhizal fungi (Glomeromycota associated with roots of plants

    Directory of Open Access Journals (Sweden)

    Sławomir Kowalczyk

    2013-12-01

    Full Text Available The results of studies of the occurrence of arbuscular mycorrhizal fungi (AMF and arbuscular mycorrhizae of the phylum Glomeromycota associated with roots of 31 cultivated, uncultivated and protected plant species growing at 103 sites of the Lubuskie province NW Poland are presented and discussed. The AMF most frequently found were members of the genus Glomus. Other relatively frequently revealed fungi were Scutellospora spp. Spore populations of AMF generally were more abundant and diverse in cultivated soils. Most protected plant species harboured AMF.

  10. Nested multiplex PCR——A feasible technique to study partial community of arbuscular mycorrhizal fungi in field-growing plant root

    Institute of Scientific and Technical Information of China (English)

    DONG Xiuli; ZHAO Bin

    2006-01-01

    Plant can be infected by different arbuscular mycorrhizal fungi, but little is known about the interaction between them within root tissues mainly because different species cannot be distinguished on the basis of fungal structure. Accurate species identification of Arbuscular mycorrhizal fungi (AMF) colonized in plant roots is the cornerstone of mycorrhizal study, yet this fundamental step is impossible through its morphological character alone. For accurate, rapid and inexpensive detection of partial mycorrhizal fungal community in plant roots, a nested multiplex polymerase chain reaction (PCR) was developed in this study. Five discriminating primers designed based on the variable region of the 5( end of the large ribosomal subunit were used in the experiment for testing their specificity and the sensitivity in nested PCR by using spores from Glomus mosseae (BEG12), Glomus intraradices (BEG141), Scutellospora castaneae (BEG1) and two unidentified Glomus sp. HAUO3 and HAUO4. The feasibility assay of nested multiplex PCR was conducted by use of spore mixture, Astragalus sinicum roots co-inoculated with 4 species of arbuscular mycorrhizal fungi from pot cultures and 15 different field-growing plant roots respectively after analyses of the compatibility of primers. The result indicated that the sensitivity was in the same range as that of the corresponding single PCR reaction. Overall accuracy was 95%. The efficiency and sensitivity of this multiplex PCR procedure provided a rapid and easy way to simultaneously detect several of arbuscular mycorrhizal fungal species in a same plant root system.

  11. Interactions between arbuscular mycorrhizal fungi and organic material substrates.

    Science.gov (United States)

    Hodge, Angela

    2014-01-01

    Arbuscular mycorrhizal (AM) associations are widespread and form between ca. two-thirds of all land plants and fungi in the phylum Glomeromycota. The association is a mutualistic symbiosis with the fungi enhancing nutrient capture for the plant while obtaining carbon in return. Although arbuscular mycorrhizal fungi (AMF) lack any substantial saprophytic capability they do preferentially associate with various organic substrates and respond by hyphal proliferation, indicating the fungus derives a benefit from the organic substrate. AMF may also enhance decomposition of the organic material. The benefit to the host plant of this hyphal proliferation is not always apparent, particularly regarding nitrogen (N) transfer, and there may be circumstances under which both symbionts compete for the N released given both have a large demand for N. The results of various studies examining AMF responses to organic substrates and the interactions with other members of the soil community will be discussed.

  12. Mycorrhizal status and diversity of fungal endophytes in roots of common buckwheat (Fagopyrum esculentum) and tartary buckwheat (F. tataricum).

    Science.gov (United States)

    Likar, Matevz; Bukovnik, Urska; Kreft, Ivan; Chrungoo, Nikhil K; Regvar, Marjana

    2008-09-01

    To determine the mycorrhizal status and to identify the fungi colonising the roots of the plants, common buckwheat (Fagopyrum esculentum) and tartary buckwheat (F. tataricum) were inoculated with an indigenous fungal mixture from a buckwheat field. Root colonisation was characterised by the hyphae and distinct microsclerotia of dark septate endophytes, with occasional arbuscules and vesicles of arbuscular mycorrhizal fungi. Sequences of arbuscular mycorrhizal fungi colonising tartary buckwheat clustered close to the Glomus species group A. Sequences with similarity to the Ceratobasidium/Rhizoctonia complex, a putative dark septate endophyte fungus, were amplified from the roots of both common and tartary buckwheat. To the best of our knowledge, this is the first report of arbuscular mycorrhizal colonisation in tartary buckwheat and the first molecular characterisation of these fungi that can colonise both of these economically important plant species.

  13. 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.

  14. Effects of eco-environmental factors on the production and distribution of arbuscular mycorrhizal fungal spores%生态环境因子对AM真菌孢子形成与分布的作用机制

    Institute of Scientific and Technical Information of China (English)

    孙向伟; 王晓娟; 陈牧; 豆存艳; 高飞翔; 金樑

    2011-01-01

    The number of spores in soil is an important indicator of the formation and distribution of arbuscular mycorrhizal (AM) fungi. The distribution of spores is mainly affected by climatic factors, soil properties, herbivores, host plants, and farming systems. Climatic factors and seasonal dynamics are the two main factors which determine the generation and distribution of AM fungal spores, including the infection, sporulation, and distribution of AM fungi by direct effects on the fungi or indirect effects through the host plants. Soil is the natural medium for spores. The distribution of spores in the soil ecosystem is mainly influenced by soil type, pH, soil moisture, permeability, nutrient content, and soil microorganisms. Host plants, herbivores, and farming measures also have an important impact on the AM fungal community. On the basis of the above, the influence of the intra- and inter-relationship of ecological factors on AM fungal spores distribution, and perspectives on the dynamics of communities in mycorrhizal ecology are discussed.%在自然土壤生态系统中,丛枝菌根(AM)真菌孢子的数量与菌根共生体的形成和分布具有密切的相关性,关注AM真菌孢子的形成与分布机制对于揭示菌根共生体的生态学功能具有重要意义.其中,探究外界环境因子对抱子分布的影响已经成为当前菌根生态学研究的热点问题之一.研究表明,影响抱子形成和分布的因素主要包括气候因子、土壤理化因子、草食动物、宿主植物种类以及耕作制度等.气候因子和季节动态是决定AM真菌孢子形成和分布的主要因子,它通过对AM真菌的直接作用,或者是通过对宿主植物的间接作用影响AM真菌的侵染、产孢和分布;土壤是抱子的天然培养基,土壤理化性状影响孢子分布的要素主要有土壤类型,pH值、土壤湿度、通透性、营养元素含量以及土壤微生物等;宿主植物类型、草食动物和农业耕作措施

  15. 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.

  16. Recently fixed carbon allocation in strawberry plants and concurrent inorganic nitrogen uptake through arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Tomè, Elisabetta; Tagliavini, Massimo; Scandellari, Francesca

    2015-05-01

    Most crop species form a symbiotic association with arbuscular mycorrhizal (AM) fungi, receiving plant photosynthate and exchanging nutrients from the soil. The plant carbon (C) allocation to AM fungi and the nitrogen feedback are rarely studied together. In this study, a dual (13)CO2 and (15)NH4(15)NO3 pulse labeling experiment was carried out to determine the allocation of recent photosynthates to mycorrhizal hyphae and the translocation of N absorbed by hyphae to strawberry plants. Plants were grown in pots in which a 50 μm mesh net allowed the physical separation of the mycorrhizal hyphae from the roots in one portion of the pot. An inorganic source of (15)N was added to the hyphal compartment at the same time of the (13)CO2 pulse labeling. One and seven days after pulse labeling, the plants were destructively harvested and the amount of the recently fixed carbon (C) and of the absorbed N was determined. (13)C allocated to belowground organs such as roots and mycorrhizal hyphae accounted for an average of 10%, with 4.3% allocated to mycorrhizal hyphae within the first 24h after the pulse labeling. Mycorrhizae absorbed labeled inorganic nitrogen, of which almost 23% was retained in the fungal mycelium. The N uptake was linearly correlated with the (13)C fixed by the plants suggesting a positive correlation between a plant photosynthetic rate and the hyphal absorption capacity.

  17. 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.

  18. Arbuscular mycorrhizal fungi (Glomeromycota of the Vistula Bar

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-08-01

    Full Text Available The occurrence of arbuscular mycorrhizal fungi (AMF of the, phylum Glomeromycota associated with plants of maritime sand dunes of the Vistula Bar localed in north-eastern Poland was investigated. The presence of AMF was revealed based on spores isolated from field-collected root-rhizosphere soil mixtures and two-cycle pot trap cultures established with parts of these mixtures. The mixtures came from under five species in four plant families. Spores of AMF occurred in 54.8% of the field samples and belonged to eight species. Additionally, culturing of root-soil mixtures in trap cultures revealed nine species and three undescribed morphotypes carlier not found in the field samples. Considering the number of records of species and morphotypes in the field samples and trap cultures, the fungal species most frequently occurring in dunes of the Vistula Bar is Scutellospora dipurpurescens, followed by Archaeospora trappei, Glomus laccatum, and Scu. armeniaca. The overall average spore abundance in the field samples is low (4.48, range O-3l in 100g dry soil. The ovcrall average species richness determined based on spores from both the field and trap cultures was 2 l and ranged from 0 lo 7 in 100g dry soil. The plant harbouring the highest number of species of AMF was Festuca rubra. Of the maritime dune sites of Poland examined to date, the species composition of AMF of the Vistula Bar is most similar to that of the Słowiński National Park. When the comparisons included 15 maritime dune areas located outside Poland, the highest similarity occurred in the Vistula Bar/Canada comparison.

  19. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    JIN HaiRu

    2009-01-01

    Bi-directional translocatlon and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycellum were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N-and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra-phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those In nitrate or exogenous Arg; however, glycerol supplied as an external car-bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio-synthesized In the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks.Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either In the mycorrhizal compartment or in the fungal compartment. Once Arg was translo-cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled In the fungal compartment, respectively. Evidently Orn formation indi-cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  20. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  1. Nested multiplex PCR--a feasible technique to study partial community of arbuscular mycorrhizal fungi in field-growing plant root.

    Science.gov (United States)

    Dong, Xiuli; Zhao, Bin

    2006-08-01

    Plant can be infected by different arbuscular mycorrhizal fungi, but little is known about the interaction between them within root tissues mainly because different species cannot be distinguished on the basis of fungal structure. Accurate species identification of Arbuscular mycorrhizal fungi (AMF) colonized in plant roots is the cornerstone of mycorrhizal study, yet this fundamental step is impossible through its morphological character alone. For accurate, rapid and inexpensive detection of partial mycorrhizal fungal community in plant roots, a nested multiplex polymerase chain reaction (PCR) was developed in this study. Five discriminating primers designed based on the variable region of the 5' end of the large ribosomal subunit were used in the experiment for testing their specificity and the sensitivity in nested PCR by using spores from Glomus mosseae (BEG12), Glomus intraradices (BEG141), Scutellospora castaneae (BEG1) and two unidentified Glomus sp. HAUO3 and HAUO4. The feasibility assay of nested multiplex PCR was conducted by use of spore mixture, Astragalus sinicum roots co-inoculated with 4 species of arbuscular mycorrhizal fungi from pot cultures and 15 different field-growing plant roots respectively after analyses of the compatibility of primers. The result indicated that the sensitivity was in the same range as that of the corresponding single PCR reaction. Overall accuracy was 95%. The efficiency and sensitivity of this multiplex PCR procedure provided a rapid and easy way to simultaneously detect several of arbuscular mycorrhiza fungal species in a same plant root system.

  2. Arbuscular mycorrhizal symbiosis of herbaceous invasive neophytes in the Czech Republic

    OpenAIRE

    Štajerová, Kateřina

    2009-01-01

    I have studied arbuscular mycorrhizal symbiosis of 44 herbaceous invasive neophytes occuring in the Czech Republic. My results show that about 70% of the examined species are capable to form symbiotic association with arbuscular mycorrhizal fungi (AMF) in the field. To my knowledge, mycorrhizal status of 23 invasive species is reported here for the first time. I predicted, based on the hypothesis of Urcelay & Díaz (2003), that the intensity of AMF in the roots of invasive species will be corr...

  3. Application ofArbuscular Mycorrhizal Inocula Might Be A Promising Method in the Restoration of Severely Degraded Wetlands%Application of Arbuscular Mycorrhizal Inocula Might Be A Promising Method in the Restoration of Severely Degraded Wetlands

    Institute of Scientific and Technical Information of China (English)

    De Gao

    2013-01-01

    The application of arbuscular mycorrhizal (AM) inocula in severely degraded wetlands could ensure success in restoration.Mycorrhizal fungi play an important role in plant individual' s survival and development in a low nutrient condition.Based on the importance that mycorrhizal fungi have to their host plants,mycorrhizal inocula have been produced and applied in terrestrial ecosystems in order to let the plants become mycorrhizal.However,mycorrhizal inocula have not been used in wetland restorations,despite increasing evidence that mycorrhizal fungi are commonly found in various wetland systems and have the ability to survive under anoxic conditions.Evidence also shows that mycorrhizal fungal inocula in the soil could have been destroyed in the degraded wetland or could be destroyed during traditional wetland restoration process.Therefore,AM inocula production is strongly recommended for wetland restoration.In this paper,I will argue that AM inocula production is required when introduced recovery is necessary,and aeroponic culture technique is a preferable method to produce AM inocula.Last,a renewed wetland restoration flow chart is summarized.

  4. [Effect of the spatial and seasonal soil heterogeneity over arbuscular mycorrhizal fungal spore abundance in the semi-arid valley of Tehuacán-Cuicatlán, Mexico].

    Science.gov (United States)

    Camargo-Ricalde, Sara Lucía; Esperón-Rodríguez, Manuel

    2005-01-01

    Recent studies have shown that some species of Mimosa (Leguminosae-Mimosoideae) create resource islands (RI), rich in soil organic matter and nutrients, as well as in arbuscular mycorrhyzal fungal (AMF) spores, in the semi-arid Valley of Tehuacán-Cuicatlán. The relevance of this fact is that arid and semi-arid regions are characterized by low fertility soils and scarce precipitation, limiting plant species growth and development; this explains why the presence of AM fungi may be advantageous for mycorrhizal desert plants. Fluctuations in AMF spore numbers could be related to environmental, seasonal and soil factors which affect AMF sporulation, in addition to the life history of the host plant. The aim of this study was to asses the impact of spatial (resource islands vs open areas, OA) and seasonal (wet season vs start of dry season vs dry season) soil heterogeneity in the distribution and abundance of AMF spores in four different study sites within the Valley. We registered AMF spores in the 120 soil samples examined. Significant differences in the number of AMF spores were reported in the soil below the canopy of Mimosa species (RI) comparing with OA (RI > OA), and between Mimosa RI themselves when comparing along a soil gradient within the RI (soil near the trunk > soil below the middle of the canopy > soil in the margin of the canopy > OA); however, there were no significant differences between the soil closest to the trunk vs middle, and margin 's OA. Finally, more spores were reported in the soil collected during the wet season than during the dry season (wet > start of dry > dry). Therefore, the distribution of AMF spores is affected by spatial and seasonal soil heterogeneity. This study points out the relevance of Mimosa RI as AMF spore reservoirs and the potential importance of AM fungi for plant species survivorship and establishment in semi-arid regions. AM fungi have recently been recognized as an important factor determining plant species diversity

  5. 茂兰喀斯特森林圆叶乌桕AM真菌多样性研究%Arbuscular Mycorrhizal Fungal Diversity in Sapium Rotundifolium in Maolan Karst Forest

    Institute of Scientific and Technical Information of China (English)

    谭金玉; 张传博; 罗充

    2012-01-01

    对贵州省荔波县茂兰国家自然保护区圆叶乌桕(Sapium rotundifolium Hemsl)的丛枝茵根(Arbuscular mycorrhizal,AM)真菌进行了初步分离、鉴定与多样性分析.结果表明,乌桕根系的菌根侵染率为44.3%;从乌桕根系土壤中分离到AM真菌2个属29种,分别为球囊霉属(Glomus)21种、无梗囊霉属(Acaulosp ora)8种.其中,球囊霉属(Glomus)为优势属,枫香球囊霉(G.liquidambari)和凹坑无梗囊霉(A.excavatadun)为优势种.%Arbuscular mycorrhizal fungi in Sapium rotundifolium Hemsl. In Maolan National Nature Reserve of Libo in Guizhou province was isolated and identified to study their diversity. The result showed that the root colonization rate of 5. Rotundifolium was 44.3%. 29 species in 2 genera(21 Glomus species and 8 Acaulospora species) were identified from the rhi-zospheres soil of S. Rotundifolium. Glomus was the dominant genus; while G. Liquidambari and A. Excavatadun were dominant species.

  6. [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.

  7. Interactive effects of root endophytes and arbuscular mycorrhizal fungi on an experimental plant community.

    Science.gov (United States)

    Rillig, Matthias C; Wendt, Stefanie; Antonovics, Janis; Hempel, Stefan; Kohler, Josef; Wehner, Jeannine; Caruso, Tancredi

    2014-01-01

    Plant-soil microbial interactions have moved into focus as an important mechanism for understanding plant coexistence and composition of communities. Both arbuscular mycorrhizal (AM) as well as other root endophytic fungi co-occur in plant roots, and therefore have the potential to influence relative abundances of plant species in local assemblages. However, no study has experimentally examined how these key root endosymbiont groups might interact and affect plant community composition. Here, using an assemblage of five plant species in mesocosms in a fully factorial experiment, we added an assemblage of AM fungi and/or a mixture of root endophytic fungal isolates, all obtained from the same grassland field site. The results demonstrate that the AM fungi and root endophytes interact to affect plant community composition by changing relative species abundance, and consequently aboveground productivity. Our study highlights the need to explicitly consider interactions of root-inhabiting fungal groups in studies of plant assemblages.

  8. 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.

  9. 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.

  10. 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.

  11. Arbuscular mycorrhizal and dark septate endophyte associations of medicinal plants

    Directory of Open Access Journals (Sweden)

    Szymon Zubek

    2011-10-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF and dark septate endophyte (DSE associations were studied in 36 medicinal plant species from 33 genera and 17 families, collected from the Botanical Garden of the Jagiellonian University in Kraków. Arbuscular mycorrhiza (AM was found in 34 species (94%; 26 were of the Arum-type, 4 – Paris and 4 taxa revealed intermediate morpho­logy. The abundance of AMF hyphae in roots varied with particular species, ranging from 2.5% (Helianthus tuberosus to 77.9% (Convallaria majalis. The mycelium of DSE was observed in 13 plant species (36%, however, the percentage of root colonization by these fungi was low. Spores of 7 AMF species (Glomeromycota were isolated from trap cultures established from rhizosphere soils of the investigated plants: Archaeospora trappei (Archaeosporaceae, Glomus aureum, Glomus caledonium, Glomus claroideum, Glomus constrictum, Glomus mosseae, Glomus versiforme (Glomeraceae. Our results are the first detailed report of root endophyte associations of the plant species under study. Moreover, the mycorrhizal status of 14 plant species is reported for the first time.

  12. 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.

  13. [Colonization of arbuscular mycorrhizal fungi and dark septate endophytes in Panax notoginseng].

    Science.gov (United States)

    Zhang, Zhihui; Chen, Di; Zhao, Dandan; Jin, Hang; Li, Lingfei

    2011-09-01

    Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) colonizing Panax notoginseng in three main producing areas in Wenshan Prefecture of Yunan province were investigated. The fungal colonization of 144 roots samples including healthy and rot roots of P. notoginseng with different age were observed by means of acid fuchsin stain. The results showed that P. notoginseng was the typical arbuscular mycorrhizal plant. Although there was no significant difference in AMF and DSE colonization among three sites, the total colonization of AMF was significantly higher than that of DSE. Statistical analysis demonstrated that the fresh weight of P. notoginseng root was positively significantly correlated with the colonization of AMF, but not with the colonization of DSE. These results suggest that AMF may play more important role than DSE in improving the yield and quality of P. notoginseng. Furthermore, AMF colonization of healthy P. notoginseng was higher than that of plant with root rot, which suggested that AMF could defend P. notoginseng against root rot pathogens. AMF have great potentiality and broad prospect to control root rot of P. notoginseng.

  14. Decline of arbuscular mycorrhizal fungi in northern hardwood forests exposed to chronic nitrogen additions.

    Science.gov (United States)

    van Diepen, Linda T A; Lilleskov, Erik A; Pregitzer, Kurt S; Miller, R Michael

    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. Abundance of AMF was measured by staining and ocular estimation, as well as by analyzing for the AMF indicator fatty acid 16:1omega5c in phospholipid (biomass indicator) and neutral lipid (lipid storage indicator) fractions. Arbuscular mycorrhizal fungal biomass, storage structures and lipid storage declined in response to N addition measured by both methods. This pattern was found when AM response was characterized as colonization intensity, on an areal basis and in proportion to maple above-ground biomass. The phospholipid fraction of the fatty acid 16:1omega5c was positively correlated with total AMF colonization and the neutral lipid fraction with vesicle colonization. Decreased AMF abundance with simulated N deposition suggests reduced C allocation to these fungi or a direct soil N-mediated decline. The fatty acid (phospholipid and neutral lipid fractions) 16:1omega5c was found to be a good indicator for AMF active biomass and stored energy, respectively.

  15. Protein actors sustaining arbuscular mycorrhizal symbiosis: underground artists break the silence.

    Science.gov (United States)

    Recorbet, Ghislaine; Abdallah, Cosette; Renaut, Jenny; Wipf, Daniel; Dumas-Gaudot, Eliane

    2013-07-01

    The roots of most land plants can enter a relationship with soil-borne fungi belonging to the phylum Glomeromycota. This symbiosis with arbuscular mycorrhizal (AM) fungi belongs to the so-called biotrophic interactions, involving the intracellular accommodation of a microorganism by a living plant cell without causing the death of the host. Although profiling technologies have generated an increasing depository of plant and fungal proteins eligible for sustaining AM accommodation and functioning, a bottleneck exists for their functional analysis as these experiments are difficult to carry out with mycorrhiza. Nonetheless, the expansion of gene-to-phenotype reverse genetic tools, including RNA interference and transposon silencing, have recently succeeded in elucidating some of the plant-related protein candidates. Likewise, despite the ongoing absence of transformation tools for AM fungi, host-induced gene silencing has allowed knockdown of fungal gene expression in planta for the first time, thus unlocking a technological limitation in deciphering the functional pertinence of glomeromycotan proteins during mycorrhizal establishment. This review is thus intended to draw a picture of our current knowledge about the plant and fungal protein actors that have been demonstrated to be functionally implicated in sustaining AM symbiosis mostly on the basis of silencing approaches.

  16. 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.

  17. Seven years of carbon dioxide enrichment, nitrogen fertilization and plant diversity influence arbuscular mycorrhizal fungi in a grassland ecosystem.

    Science.gov (United States)

    Antoninka, Anita; Reich, Peter B; Johnson, Nancy Collins

    2011-10-01

    • We tested the prediction that the abundance and diversity of arbuscular mycorrhizal (AM) fungi are influenced by resource availability and plant community composition by examining the joint effects of carbon dioxide (CO(2) ) enrichment, nitrogen (N) fertilization and plant diversity on AM fungi. • We quantified AM fungal spores and extramatrical hyphae in 176 plots after 7 yr of treatment with all combinations of ambient or elevated CO(2) (368 or 560 ppm), with or without N fertilization (0 or 4 g Nm(-2) ), and one (monoculture) or 16 host plant species (polyculture) in the BioCON field experiment at Cedar Creek Ecosystem Science Reserve, Minnesota, USA. • Extramatrical hyphal lengths were increased by CO(2) enrichment, whereas AM spore abundance decreased with N fertilization. Spore abundance, morphotype richness and extramatrical hyphal lengths were all greater in monoculture plots. A structural equation model showed AM fungal biovolume was most influenced by CO(2) enrichment, plant community composition and plant richness, whereas spore richness was most influenced by fungal biovolume, plant community composition and plant richness. • Arbuscular mycorrhizal fungi responded to differences in host community and resource availability, suggesting that mycorrhizal functions, such as carbon sequestration and soil stability, will be affected by global change.

  18. Role of gibberellins during arbuscular mycorrhizal formation in tomato: new insights revealed by endogenous quantification and genetic analysis of their metabolism in mycorrhizal roots.

    Science.gov (United States)

    Martín-Rodríguez, José Ángel; Ocampo, Juan Antonio; Molinero-Rosales, Nuria; Tarkowská, Danuše; Ruíz-Rivero, Omar; García-Garrido, José Manuel

    2015-05-01

    Gibberellins (GAs) are key regulators of plant growth and development and recent studies suggest also a role during arbuscular mycorrhizal (AM) formation. Here, complementary approaches have been used to obtain a clearer picture that correlates AM fungal development inside roots with GA metabolism. An extensive analysis of genes associated with GA metabolism as well as a quantification of GA content in roots was made. Application of GA3 and its biosynthesis inhibitor prohexadione calcium (PrCa) combined with a GA-constitutive response mutant (procera) were used to determine whether fungal colonization is altered by the level of these hormones or by changes in the GA-signaling pathway. The increased levels of specific GAs from the 13-hydroxylation pathway in mycorrhizal roots correlate closely with the increased expression of genes coding enzymes from the GA biosynthetic trail. The imbalance of GAs in tomato roots caused by exogenous applications of GA3 or PrCa affects arbuscules in both negative and positive ways, respectively. In addition, procera plants were adversely affected by the mycorrhization process. Our findings demonstrate that an imbalance in favor of an increased amount of GAs negatively affects the frequency of mycorrhization and particularly the arbuscular abundance in tomato mycorrhizal roots and the results point out that AM formation is associated with a change in the 13-hydroxylation pathway of GAs.

  19. 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

    2015-01-01

    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 seedli

  20. 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

  1. Two Arbuscular Mycorrhizal Fungi Colonizing Maize Under Different Phosphorus Regimes in a Compartment Cultivation System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A modified glass bead compartment cultivation system was used to compare some chemical and biological properties of the two arbuscular mycorrhizal (AM) fungi Glomus mosseae and Glomus versiforme using maize (Zea mays) as the host plant with four added levels of available phosphorus (P). The proportion of host plant root length infected was determined at harvest. Shoot and root yields and nutrient concentrations were determined, together with the nutrient concentrations in the AM fungal external mycelium. The morphology of various mycorrhizal structures of the two AM fungi was also compared by microscopic observation. Inoculation with G. mosseae gave higher plant yields than that with G. versiforme, and the two fungi responded differently in infection rate to available phosphorus level. Root infection rate of mycorrhizal maize colonized by G. mosseae decreased markedly with increasing P level, and there was very poor development of the extraradical mycelium at the highest rate of P addition. In contrast, G. versiforme showed greater tolerance to increasing P level. Elemental analysis showed that phosphorus, copper and zinc concentrations in the external mycelium differed between the two fungi and were much higher than those in the host plant.Differences in the morphology of the two fungi were also observed.

  2. Plant Identity Exerts Stronger Effect than Fertilization on Soil Arbuscular Mycorrhizal Fungi in a Sown Pasture.

    Science.gov (United States)

    Zheng, Yong; Chen, Liang; Luo, Cai-Yun; Zhang, Zhen-Hua; Wang, Shi-Ping; Guo, Liang-Dong

    2016-10-01

    Arbuscular mycorrhizal (AM) fungi play key roles in plant nutrition and plant productivity. AM fungal responses to either plant identity or fertilization have been investigated. However, the interactive effects of different plant species and fertilizer types on these symbiotic fungi remain poorly understood. We evaluated the effects of the factorial combinations of plant identity (grasses Avena sativa and Elymus nutans and legume Vicia sativa) and fertilization (urea and sheep manure) on AM fungi following 2-year monocultures in a sown pasture field study. AM fungal extraradical hyphal density was significantly higher in E. nutans than that in A. sativa and V. sativa in the unfertilized control and was significantly increased by urea and manure in A. sativa and by manure only in E. nutans, but not by either fertilizers in V. sativa. AM fungal spore density was not significantly affected by plant identity or fertilization. Forty-eight operational taxonomic units (OTUs) of AM fungi were obtained through 454 pyrosequencing of 18S rDNA. The OTU richness and Shannon diversity index of AM fungi were significantly higher in E. nutans than those in V. sativa and/or A. sativa, but not significantly affected by any fertilizer in all of the three plant species. AM fungal community composition was significantly structured directly by plant identity only and indirectly by both urea addition and plant identity through soil total nitrogen content. Our findings highlight that plant identity has stronger influence than fertilization on belowground AM fungal community in this converted pastureland from an alpine meadow.

  3. Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi

    Institute of Scientific and Technical Information of China (English)

    E.Uma; K.Sathiyadash; J.Loganathan; T.Muthukumar

    2012-01-01

    A survey of 35 tree species (belonging to 28 genera in 19families) in Aliyar,South India was carried out to ascertain their arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal status.All the tree species examined had AM association.AM and DSE colonization is reported for the first time in 20 and 14 species respectively.Cooccurrence of AM and DSE was observed in 14 (40%) tree species.The extent of DSE colonization was inversely related to the extent of AM fungal colonization.Six tree species had Arum-type,18 had intermediatetype and 1l had typical Paris-type AM morphology.AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil.AM fungal spore numbers were not related to the extent of AM colonization and Glomus dominated spore diversity.AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species.The occurrence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this association in future conservation programmes of these species.

  4. Symbiotic interaction of endophytic bacteria with arbuscular mycorrhizal fungi and its antagonistic effect on Ganoderma boninense.

    Science.gov (United States)

    Sundram, Shamala; Meon, Sariah; Seman, Idris Abu; Othman, Radziah

    2011-08-01

    Endophytic bacteria (Pseudomonas aeruginosa UPMP3 and Burkholderia cepacia UMPB3), isolated from within roots of oil palm (Elaeis guineensis Jacq.) were tested for their presymbiotic effects on two arbuscular mcorrhizal fungi, Glomus intraradices UT126 and Glomus clarum BR152B). These endophytic bacteria were also tested for antagonistic effects on Ganoderma boninense PER 71, a white wood rot fungal pathogen that causes a serious disease in oil palm. Spore germination and hyphal length of each arbuscular mycorrhizal fungal (AMF) pairing with endophytic bacteria was found to be significantly higher than spores plated in the absence of bacteria. Scanning electron microscopy (SEM) showed that the endophytic bacteria were scattered, resting or embedded on the surface hyaline layer or on the degraded walls of AMF spores, possibly feeding on the outer hyaline spore wall. The antagonistic effect of the endophytic bacteria was expressed as severe morphological abnormalities in the hyphal structures of G. boninense PER 71. The effects of the endophytic bacteria on G. boninense PER 71 hyphal structures were observed clearly under SEM. Severe inter-twisting, distortion, lysis and shriveling of the hyphal structures were observed. This study found that the effect of endophytic bacteria on G. intraradices UT126 and G. clarum BR152B resembled that of a mycorrhiza helper bacteria (MHB) association because the association significantly promoted AMF spore germination and hyphal length. However, the endophytic bacteria were extremely damaging to G. boninense PER 71.

  5. Glomus drummondii and G. walkeri, two new species of arbuscular mycorrhizal fungi (Glomeromycota).

    Science.gov (United States)

    Błaszkowski, Janusz; Renker, Carsten; Buscot, François

    2006-05-01

    Two new ectocarpic arbuscular mycorrhizal fungal species, Glomus drummondii and G. walkeri (Glomeromycota), found in maritime sand dunes of northern Poland and those adjacent to the Mediterranean Sea are described and illustrated. Mature spores of G. drummondii are pastel yellow to maize yellow, globose to subglobose, (58-)71(-85) micromdiam, or ovoid, 50-80x63-98 microm. Their wall consists of three layers: an evanescent, hyaline, short-lived outermost layer, a laminate, smooth, pastel yellow to maize yellow middle layer, and a flexible, smooth, hyaline innermost layer. Spores of G. walkeri are white to pale yellow, globose to subglobose, (55-)81(-95) micromdiam, or ovoid, 60-90x75-115 microm, and have a spore wall composed of three layers: a semi-permanent, hyaline outermost layer, a laminate, smooth, white to pale yellow middle layer, and a flexible, smooth, hyaline innermost layer. In Melzer's reagent, only the inner- and outermost layers stain reddish white to greyish rose in G. drummondii and G. walkeri, respectively. Both species form vesicular-arbuscular mycorrhizae in one-species cultures with Plantago lanceolata as the host plant. Phylogenetic analyses of the ITS and parts of the LSU of the nrDNA of spores placed both species in Glomus Group B sensu Schüssler et al. [Schüssler A, Schwarzott D, Walker C, 2001. A new fungal phylum, the Glomeromycota: phylogeny and evolution. Mycolological Research 105: 1413-1421.].

  6. Expression of phenazine biosynthetic genes during the arbuscular mycorrhizal symbiosis of Glomus intraradices

    Directory of Open Access Journals (Sweden)

    Dionicia Gloria León-Martínez

    2012-06-01

    Full Text Available To explore the molecular mechanisms that prevail during the establishment of the arbuscular mycorrhiza symbiosis involving the genus Glomus, we transcriptionally analysed spores of Glomus intraradices BE3 during early hyphal growth. Among 458 transcripts initially identified as being expressed at presymbiotic stages, 20% of sequences had homology to previously characterized eukaryotic genes, 30% were homologous to fungal coding sequences, and 9% showed homology to previously characterized bacterial genes. Among them, GintPbr1a encodes a homolog to Phenazine Biosynthesis Regulator (Pbr of Burkholderia cenocepacia, an pleiotropic regulatory protein that activates phenazine production through transcriptional activation of the protein D isochorismatase biosynthetic enzyme phzD (Ramos et al., 2010. Whereas GintPbr1a is expressed during the presymbiotic phase, the G. intraradices BE3 homolog of phzD (BGintphzD is transcriptionally active at the time of the establishment of the arbuscular mycorrhizal symbiosis. DNA from isolated bacterial cultures found in spores of G. intraradices BE3 confirmed that both BGintPbr1a and BGintphzD are present in the genome of its potential endosymbionts. Taken together, our results indicate that spores of G. intraradices BE3 express bacterial phenazine biosynthetic genes at the onset of the fungal-plant symbiotic interaction.

  7. Evolutionary conservation of a phosphate transporter in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Karandashov, Vladimir; Nagy, Réka; Wegmüller, Sarah; Amrhein, Nikolaus; Bucher, Marcel

    2004-04-20

    Arbuscular mycorrhizae are ancient symbioses that are thought to have originated >400 million years ago in the roots of plants, pioneering the colonization of terrestrial habitats. In these associations, a key process is the transfer of phosphorus as inorganic phosphate to the host plant across the fungus-plant interface. Mycorrhiza-specific phosphate transporter genes and their regulation are conserved in phylogenetically distant plant species, and they are activated selectively by fungal species from the phylum Glomeromycota. The potato phosphate transporter gene StPT3 is expressed in a temporally defined manner in root cells harboring various mycorrhizal structures, including thick-coiled hyphae. The results highlight the role of different symbiotic structures in phosphorus transfer, and they indicate that cell-cell contact between the symbiotic partners is required to induce phosphate transport.

  8. Detection and characterization of mycoviruses in arbuscular mycorrhizal fungi by deep-sequencing.

    Science.gov (United States)

    Ezawa, Tatsuhiro; Ikeda, Yoji; Shimura, Hanako; Masuta, Chikara

    2015-01-01

    Fungal viruses (mycoviruses) often have a significant impact not only on phenotypic expression of the host fungus but also on higher order biological interactions, e.g., conferring plant stress tolerance via an endophytic host fungus. Arbuscular mycorrhizal (AM) fungi in the phylum Glomeromycota associate with most land plants and supply mineral nutrients to the host plants. So far, little information about mycoviruses has been obtained in the fungi due to their obligate biotrophic nature. Here we provide a technical breakthrough, "two-step strategy" in combination with deep-sequencing, for virological study in AM fungi; dsRNA is first extracted and sequenced using material obtained from highly productive open pot culture, and then the presence of viruses is verified using pure material produced in the in vitro monoxenic culture. This approach enabled us to demonstrate the presence of several viruses for the first time from a glomeromycotan fungus.

  9. Arbuscular Mycorrhizal (AM) Diversity in Prosopis cineraria (L.) Druce Under Arid Agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Neelam Verma; Jagadish Chandra Tarafdar; Krishna Kant Srivastava; Jitendra Panwar

    2008-01-01

    Arbuscular mycorrhizal (AM) fungi associated with Prosopis cineraria (Khejri) were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomus fasciculatum were found to be most abundant under Prosopis cineraria.

  10. Allocation of plant carbon to foraging and storage in arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Gavito, Mayra E; Olsson, Pål Axel

    2003-07-01

    Abstract Foraging strategies, the cost-benefit associated with the search for new resources, have only begun to be explored in arbuscular mycorrhizal fungi (AMF). We show the use of (13)C-labelling, via shoot photosynthesis, of the 16:1omega5 fatty acid biomarker (the dominant and rather specific fatty acid in AMF storage lipids) to study the immediate patterns of carbon allocation to fungal lipids in response to inorganic and organic nutrient amendments. Signature fatty acid measurements, the incorporation of the label and complementary hyphal length density measurements showed that the extraradical mycelium of AMF proliferated in response to all the amendments provided whereas its development into unamended sand was minor in all treatments. We demonstrate the foraging capacity of AMF, linked to plant carbon, through their hyphal proliferation and accumulation of energy reserves.

  11. Bacterial effects on arbuscular mycorrhizal fungi and mycorrhiza development as influenced by the bacteria, fungi, and host plant.

    Science.gov (United States)

    Pivato, Barbara; Offre, Pierre; Marchelli, Sara; Barbonaglia, Bruno; Mougel, Christophe; Lemanceau, Philippe; Berta, Graziella

    2009-02-01

    Bacterial strains from mycorrhizal roots (three belonging to Comamonadaceae and one to Oxalobacteraceae) and from non-mycorrhizal roots (two belonging to Comamonadaceae) of Medicago truncatula and two reference strains (Collimonas fungivorans Ter331 and Pseudomonas fluorescens C7R12) were tested for their effect on the in vitro saprophytic growth of Glomus mosseae BEG12 and on its colonization of M. truncatula roots. Only the Oxalobacteraceae strain, isolated from barrel medic mycorrhizal roots, and the reference strain P. fluorescens C7R12 promoted both the saprophytic growth and root colonization of G. mosseae BEG12, indicating that they acted as mycorrhiza helper bacteria. Greatest effects were achieved by P. fluorescens C7R12 and its influence on the saprophytic growth of G. mosseae was compared to that on Gigaspora rosea BEG9 to determine if the bacterial stimulation was fungal specific. This fungal specificity, together with plant specificity, was finally evaluated by comparing bacterial effects on arbuscular mycorrhizal symbiosis when each of the fungal species was inoculated to two different plant species (M. truncatula and Lycopersicon esculentum). The results obtained showed that promotion of saprophytic growth by P. fluorescens C7R12 was expressed in vitro towards G. mosseae but not towards G. rosea. Bacterial promotion of mycorhization was also expressed towards G. mosseae, but not G. rosea, in roots of M. truncatula and L. esculentum. Taken together, results indicated that enhancement of arbuscular mycorrhiza development was only induced by a limited number of bacteria, promotion by the most efficient bacterial strain being fungal and not plant specific.

  12. The best for the guest: high Andean nurse cushions of Azorella madreporica enhance arbuscular mycorrhizal status in associated plant species.

    Science.gov (United States)

    Casanova-Katny, M Angélica; Torres-Mellado, Gustavo Adolfo; Palfner, Goetz; Cavieres, Lohengrin A

    2011-10-01

    Positive interactions between cushion plant and associated plants species in the high Andes of central Chile should also include the effects of fungal root symbionts. We hypothesized that higher colonization by arbuscular mycorrhizal (AM) fungi exists in cushion-associated (nursling) plants compared with conspecific individuals growing on bare ground. We assessed the AM status of Andean plants at two sites at different altitudes (3,200 and 3,600 ma.s.l.) in 23 species, particularly in cushions of Azorella madreporica and five associated plants; additionally, AM fungal spores were retrieved from soil outside and beneath cushions. 18 of the 23 examined plant species presented diagnostic structures of arbuscular mycorrhiza; most of them were also colonized by dark-septate endophytes. Mycorrhization of A. madreporica cushions showed differences between both sites (68% and 32%, respectively). In the native species Hordeum comosum, Nastanthus agglomeratus, and Phacelia secunda associated to A. madreporica, mycorrhization was six times higher than in the same species growing dispersed on bare ground at 3,600 ma.s.l., but mycorrhiza development was less cushion dependent in the alien plants Cerastium arvense and Taraxacum officinale at both sites. The ratio of AM fungal spores beneath versus outside cushions was also 6:1. The common and abundant presence of AM in cushion communities at high altitudes emphasizes the importance of the fungal root symbionts in such situations where plant species benefit from the microclimatic conditions generated by the cushion and also from well-developed mycorrhizal networks.

  13. Arbuscular mycorrhizal colonization in field-collected terrestrial cordate gametophytes of pre-polypod leptosporangiate ferns (Osmundaceae, Gleicheniaceae, Plagiogyriaceae, Cyatheaceae).

    Science.gov (United States)

    Ogura-Tsujita, Yuki; Hirayama, Yumiko; Sakoda, Aki; Suzuki, Ayako; Ebihara, Atsushi; Morita, Nana; Imaichi, Ryoko

    2016-02-01

    To determine the mycorrhizal status of pteridophyte gametophytes in diverse taxa, the mycorrhizal colonization of wild gametophytes was investigated in terrestrial cordate gametophytes of pre-polypod leptosporangiate ferns, i.e., one species of Osmundaceae (Osmunda banksiifolia), two species of Gleicheniaceae (Diplopterygium glaucum, Dicranopteris linearis), and four species of Cyatheales including tree ferns (Plagiogyriaceae: Plagiogyria japonica, Plagiogyria euphlebia; Cyatheaceae: Cyathea podophylla, Cyathea lepifera). Microscopic observations revealed that 58 to 97% of gametophytes in all species were colonized with arbuscular mycorrhizal (AM) fungi. Fungal colonization was limited to the multilayered midrib (cushion) tissue in all gametophytes examined. Molecular identification using fungal SSU rDNA sequences indicated that the AM fungi in gametophytes primarily belonged to the Glomeraceae, but also included the Claroideoglomeraceae, Gigasporaceae, Acaulosporaceae, and Archaeosporales. This study provides the first evidence for AM fungal colonization of wild gametophytes in the Plagiogyriaceae and Cyatheaceae. Taxonomically divergent photosynthetic gametophytes are similarly colonized by AM fungi, suggesting that mycorrhizal associations with AM fungi could widely occur in terrestrial pteridophyte gametophytes.

  14. [Interactions between invasive plants and arbuscular mycorrhizal fungi: a review].

    Science.gov (United States)

    Bai, Yan-fang; Guo, Shao-xia; Li, Min

    2011-09-01

    The invasion of invasive plants changes the biological community structure in their invaded lands, leading to the biodiversity loss. As an important component of soil microorganisms in terrestrial ecosystem, arbuscular mycorrhizal (AM) fungi can affect the growth performance of invasive plants. This kind of specific relations between AM fungi and invasive plants also implies that AM fungi can affect plant invasion. On the other hand, the invasion of invasive plants can affect the community structure and function of AM fungi. This paper summarized the species and harms of invasive plants in China, and discussed the relationships between AM fungi and invasive plants invasion, including the roles of AM fungi in the processes of invasive plants invasion, the effects of the invasion on AM fungi, and the interactive mechanisms between the invasion and AM fungi.

  15. 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.

  16. Chasing the structures of small molecules in arbuscular mycorrhizal signaling.

    Science.gov (United States)

    Bucher, Marcel; Wegmüller, Sarah; Drissner, David

    2009-08-01

    The arbuscular mycorrhiza (AM) is a symbiosis between most terrestrial plants and fungi of the ancient phylum Glomeromycota. AM improves the uptake of water and mineral nutrients, such as phosphorus (P) and nitrogen (N), of the host plant in exchange for photosynthetically fixed carbon. Successful colonization and a functional interaction between host plant and mycobiont are based upon exchange of signaling molecules at different stages of symbiosis development. Strigolactones, a novel class of plant hormones, are secreted by plant roots stimulating presymbiotic growth of AM fungi. Fungi release soluble signaling molecules, the enigmatic 'Myc factors', that activate early symbiotic root responses. Lysophosphatidylcholine is a lipophilic intraradical mycorrhizal signal triggering plant phosphate transporter gene expression late in AM development through a P-controlled transcriptional mechanism. This enables uptake of orthophosphate released from the AM fungus.

  17. Presence of arbuscular mycorrhizal fungi in South Florida native plants.

    Science.gov (United States)

    Fisher, Jack B; Jayachandran, K

    2005-11-01

    The roots of 27 species of South Florida plants in 15 families (including one cycad, six palms, one Smilax, and 19 dicotyledons) native to pine rockland and tropical hardwood hammock communities were examined for arbuscular mycorrhizal fungi (AMF). These plants grow in the biologically diverse but endangered Greater Everglades habitat. Roots from field-grown and potted plants were cleared and stained. All 27 species had AMF and include 14 species having an endangered or threatened status. The Paris-type colonization occurred in two species in the families Annonaceae and Smilacaceae. The Arum-type occurred in 22 species in the families Anacardiaceae, Arecaceae (Palmae), Boraginaceae, Cactaceae (questionable), Euphorbiaceae, Fabaceae, Lauraceae, Melastomataceae, Polygalaceae, Rubiaceae, Simaroubaceae, Ulmaceae, and Zamiaceae. Three species in the families Fabaceae, Lauraceae, and Simaroubaceae had a mix of Paris- and Arum-types. The results have implications for the restoration of these endangered plant communities in the Everglades.

  18. Mycorrhizal fungal communities respond to experimental elevation of soil pH and P availability in temperate hardwood forests.

    Science.gov (United States)

    Carrino-Kyker, Sarah R; Kluber, Laurel A; Petersen, Sheryl M; Coyle, Kaitlin P; Hewins, Charlotte R; DeForest, Jared L; Smemo, Kurt A; Burke, David J

    2016-03-01

    Many forests are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P), but the response of mycorrhizal fungi to changes in soil pH and P availability and how this affects tree acquisition of nutrients is not well understood. Here, we describe an ecosystem-level manipulation in 72 plots, which increased pH and/or P availability across six forests in Ohio, USA. Two years after treatment initiation, mycorrhizal fungi on roots were examined with molecular techniques, including 454-pyrosequencing. Elevating pH significantly increased arbuscular mycorrhizal (AM) fungal colonization and total fungal biomass, and affected community structure of AM and ectomycorrhizal (EcM) fungi, suggesting that raising soil pH altered both mycorrhizal fungal communities and fungal growth. AM fungal taxa were generally negatively correlated with recalcitrant P pools and soil enzyme activity, whereas EcM fungal taxa displayed variable responses, suggesting that these groups respond differently to P availability. Additionally, the production of extracellular phosphatase enzymes in soil decreased under elevated pH, suggesting a shift in functional activity of soil microbes with pH alteration. Thus, our findings suggest that elevating pH increased soil P availability, which may partly underlie the mycorrhizal fungal responses we observed.

  19. A shift from arbuscular mycorrhizal to dark septate endophytic colonization in Deschampsia flexuosa roots occurs along primary successional gradient.

    Science.gov (United States)

    Huusko, K; Ruotsalainen, A L; Markkola, A M

    2017-02-01

    Soil fungal community and dominant mycorrhizal types are known to shift along with plant community changes during primary succession. However, it is not well understood how and why root fungal symbionts and colonization types vary within the plant host when the host species is able to thrive both at young and at old successional stages with different light and nutrient resource availability. We asked (i) how root fungal colonization of Deschampsia flexuosa (Poaceae) by arbuscular mycorrhizal (AM) fungi and dark septate endophytes (DSE) changes along a postglacial primary successional land uplift gradient. As neighboring vegetation may play a role in root fungal colonization, we also asked (ii) whether removal of the dominant neighbor, Empetrum nigrum ssp. hermaphroditum (Ericaceae), affects root fungal colonization of Deschampsia. We also studied whether (iii) foliar carbon (C) and nitrogen (N) concentration of Deschampsia is related to successional changes along a land uplift gradient. AM colonization decreased (-50 %), DSE colonization increased (+200 %), and foliar C declined in Deschampsia along with increasing successional age, whereas foliar N was not affected. Empetrum removal did not affect AM colonization but increased DSE sclerotial colonization especially at older successional stages. The observed decrease in foliar C coincides with an increase in canopy closure along with increasing successional age. We suggest that the shift from an AM-dominated to a DSE-dominated root fungal community in Deschampsia along a land uplift successional gradient may be related to different nutritional benefits gained through these root fungal groups.

  20. Arbuscular mycorrhizal fungi (Glomeromycota of soils of the Lubuskie province

    Directory of Open Access Journals (Sweden)

    Sławomir Kowalczyk

    2012-12-01

    Full Text Available In the year 2003, the occurrence of arbuscular mycorrhizal fungi (AMF of the phylum Glomeromycota in cultivated and uncultivated soils of the Lubuskie province was investigated. The occurrence of AMF was examined based on 56 root and rhizosphere soils collected under 7 species of cultivated and uncultivated plants growing in 28 localities. Spores of AMF were isolated from both field-collected samples and trap cultures. They were revealed in 100% of field soils and 93.8% of trap cultures and represented 7 of the 8 recognized genera of the Glomeromycota. The arbuscular fungi occurring distinctly more frequently in the soil and root samples examined were members of the genus Glomus. The species of AMF most frequently occurring in cultivated soils of the Lubuskie province were G. claroideum, G. constrictum, G. deserticola and G. mosseae, whereas G. claroideum, G. constrictum, G. deserticola, G. mosseae, and S. dipurpurescens were more frequently found in uncultivated sites. The analysis of similarity of the species composition of AMF populations in sites of the Lubuskie province and the Western Pomeranian province earlier examined showed that (1 the occurrence in Poland of most taxa of these fungi detected in the study presented here is even and does not change with time, (2 the communities of AMF area are stable, despite the arduousness resulting from the agricultural and chemical practices conducted, and (3 the species diversity of the plants cultivated in a long period of time has no influence on the species composition of populations of AMF.

  1. Nutritional effects of indigenous arbuscular mycorrhizal associations on the sclerophyllous species Agathosma betulina

    Directory of Open Access Journals (Sweden)

    M. A. Pèrez-Fernández

    2007-09-01

    Full Text Available Relatively little is currently known about the seedling physiology of arbuscular mycorrhizal (AM Agathosma betulina, a sclerophyllous crop plant cultivated for its high-value essential oils and food additives. In addition, virtually nothing is known about the AM associations of this plant. Consequently, the effect of an indigenous community of AM fungi on P nutrition and C economy in seedlings, grown in nursery conditions, was determined during different stages of host and AM fungal establishment. AM fungal ribosomal gene sequence analyses were used to identify some of the fungi within the roots, responsible for the nutritional changes. During the early stages of host and AM fungal establishment (0 to 77 days after germination, host growth was reduced, whereas the rate of P-uptake and growth respiration was increased. Beyond 77 days of growth, the rate of P-uptake and growth respiration declined. These findings, together with results obtained after molecular analyses of root associated fungal DNA, indicate that AM fungi belonging to the genera Acaulospora and Glomus, improve P-uptake and costs of utilization during the early stages of seedling establishment in a nutrient-poor soil.

  2. Organic amendments increase phylogenetic diversity of arbuscular mycorrhizal fungi in acid soil contaminated by trace elements.

    Science.gov (United States)

    Montiel-Rozas, María Del Mar; López-García, Álvaro; Kjøller, Rasmus; Madejón, Engracia; Rosendahl, Søren

    2016-08-01

    In 1998, a toxic mine spill polluted a 55-km(2) area in a basin southward to Doñana National Park (Spain). Subsequent attempts to restore those trace element-contaminated soils have involved physical, chemical, or biological methodologies. In this study, the restoration approach included application of different types and doses of organic amendments: biosolid compost (BC) and leonardite (LEO). Twelve years after the last addition, molecular analyses of arbuscular mycorrhizal (AM) fungal communities associated with target plants (Lamarckia aurea and Chrysanthemum coronarium) as well as analyses of trace element concentrations both in soil and in plants were performed. The results showed an improved soil quality reflected by an increase in soil pH and a decrease in trace element availability as a result of the amendments and dosages. Additionally, the phylogenetic diversity of the AM fungal community increased, reaching the maximum diversity at the highest dose of BC. Trace element concentration was considered the predominant soil factor determining the AM fungal community composition. Thereby, the studied AM fungal community reflects a community adapted to different levels of contamination as a result of the amendments. The study highlights the long-term effect of the amendments in stabilizing the soil system.

  3. Arbuscular mycorrhizal fungi make a complex contribution to soil aggregation

    Science.gov (United States)

    McGee, Peter; Daynes, Cathal; Damien, Field

    2013-04-01

    Soil aggregates contain solid and fluid components. Aggregates develop as a consequence of the organic materials, plants and hyphae of arbuscular mycorrhizal (AM) fungi acting on the solid phase. Various correlative studies indicate hyphae of AM fungi enmesh soil particles, but their impact on the pore space is poorly understood. Hyphae may penetrate between particles, remove water from interstitial spaces, and otherwise re-arrange the solid phase. Thus we might predict that AM fungi also change the pore architecture of aggregates. Direct observations of pore architecture of soil, such as by computer-aided tomography (CT), is difficult. The refractive natures of solid and biological material are similar. The plant-available water in various treatments allows us to infer changes in pore architecture. Our experimental studies indicate AM fungi have a complex role in the formation and development of aggregates. Soils formed from compost and coarse subsoil materials were planted with mycorrhizal or non-mycorrhizal seedlings and the resultant soils compared after 6 or 14 months in separate experiments. As well as enmeshing particles, AM fungi were associated with the development of a complex pore space and greater pore volume. Even though AM fungi add organic matter to soil, the modification of pore space is not correlated with organic carbon. In a separate study, we visualised hyphae of AM fungi in a coarse material using CT. In this study, hyphae appeared to grow close to the surfaces of particles with limited ramification across the pore spaces. Hyphae of AM fungi appear to utilise soil moisture for their growth and development of mycelium. The strong correlation between moisture and hyphae has profound implications for soil aggregation, plant utilisation of soil water, and the distribution of water as water availability declines.

  4. Clonal diversity and population genetic structure of arbuscular mycorrhizal fungi (Glomus spp.) studied by multilocus genotyping of single spores

    DEFF Research Database (Denmark)

    Holtgrewe-Stukenbrock, Eva; Rosendahl, Søren

    2005-01-01

    characterized by SSCP (single stranded conformation polymorphism) and sequencing.   All spore genotypes were unique suggesting that no recombination was taking place in the populations. There were no overall differences in the distribution of genotypes in the two fields and identical genotypes could be sampled......A nested multiplex PCR (polymerase chain reaction) approach was used for multilocus genotyping of arbuscular mycorrhizal fungal populations. This method allowed us to amplify multiple loci from Glomus single spores in a single PCR amplification. Variable introns in the two protein coding genes Gm...

  5. Effect of Various Organic Matter stimulates Bacteria and Arbuscular Mycorrhizal Fungi Plantations on Eroded Slopes in Nepal

    Science.gov (United States)

    Shrestha Vaidya, G.; Shrestha, K.; Wallander, H.

    2009-04-01

    Erosion resulting from landslides is a serious problem in mountainous countries such as Nepal. To restore such sites it is essential to establish plant cover that protects the soil and reduces erosion. Trees and shrubs on the lower hillsides in Nepal form symbiosis with arbuscular mycorrhizal (AM) fungi and these fungi are important for the uptake of mineral nutrients from the soil. In addition, the mycelia formed by these fungi have an important function in stabilizing the soil. The success of plantations of these eroded slopes is therefore highly dependent on the extent of mycorrhizal colonization of the plants. Mycorrhizal fungi growing in symbiosis with plants are essential in this respect because they improve both plant and nutrient uptake and soil structure. We investigated the influence of organic matter and P amendment on recently produced biomass of bacteria and arbuscular mycorrhizal (AM) fungi in eroded slopes in Nepal. Eroded soil mixed with different types of organic matter was placed in mesh bags which were buried around the trees of Bauhinia purpurea and Leucaena diversifolia .This experiment were done in two seasons ( (the wet and the dry season). Signature fatty acids were used to determine bacterial and AM fungal biomass after the six month intervals. The amount and composition of AM fungal spores were analyzed in the mesh bags from the wet and dry seasons. More microbial biomass was produced during wet season than during dry season. Further more, organic matter addition enhanced the production of AM fungal and bacterial biomass during both seasons. The positive influence of organic matter addition on AM fungi could be an important contribution to plant survival, growth and nutrient composition in the soil in plantations on eroded slopes. Different AM spore communities and bacterial profiles were obtained with different organic amendments and this suggests a possible way of selecting for specific microbial communities in the management of eroded

  6. Arbuscular mycorrhizal colonization of giant sequoia (Sequoiadendron giganteum) in response to restoration practices.

    Science.gov (United States)

    Fahey, Catherine; York, Robert A; Pawlowska, Teresa E

    2012-01-01

    Interactions with soil microbiota determine the success of restoring plants to their native habitats. The goal of our study was to understand the effects of restoration practices on interactions of giant sequoia Sequoiadendron giganteum with arbuscular mycorrhizal (AM) fungi (Glomeromycota). Natural regeneration of Sequoiadendron is threatened by the absence of severe fires that create forest canopy gaps. Generating artificial canopy gaps offers an alternative tool for giant sequoia restoration. We investigated the effect of regeneration practices, including (i) sapling location within gaps, (ii) gap size and (iii) soil substrate, on AM fungal colonization of giant sequoia sapling roots in a native giant sequoia grove of the Sierra Nevada, California. We found that the extent of AM fungal root colonization was positively correlated with sapling height and light availability, which were related to the location of the sapling within the gap and the gap size. While colonization frequency by arbuscules in saplings on ash substrate was higher relative to saplings in mineral soil, the total AM fungal root colonization was similar between the substrates. A negative correlation between root colonization by Glomeromycota and non-AM fungal species indicated antagonistic interactions between different classes of root-associated fungi. Using DNA genotyping, we identified six AM fungal taxa representing genera Glomus and Ambispora present in Sequoiadendron roots. Overall, we found that AM fungal colonization of giant sequoia roots was associated with availability of plant-assimilated carbon to the fungus rather than with the AM fungal supply of mineral nutrients to the roots. We conclude that restoration practices affecting light availability and carbon assimilation alter feedbacks between sapling growth and activity of AM fungi in the roots.

  7. A Comparison of the Effects of Two Arbuscular Mycorrhizal Fungal Species on Photosynthesis, Transpiration and Water Use Efficiency of Wheat%两种丛枝菌根菌抗旱效应的比较

    Institute of Scientific and Technical Information of China (English)

    叶爱华; 袁艺; 杨莉; 蔡永萍; 田胜尼

    2003-01-01

    Drought is a major restriction to plant growth. AMF(arbuscular mycorrhizal fungi)can increase the absorption of nutrition, facilitate the growth of plant and improve drought resistance of many plants. The experiment compared the effects of two AMF species on wheat at 10% water level. The wheat inoculated with 90089 and 90036 decreased stomatal resistance, increased net photosynthetic rate, stomatal conduction,transpiration rate and WUE compared with the control.%丛枝菌根可在与植物共生的过程中增加植物对营养元素的吸收,增加植物的生长量,提高植物的抗旱抗涝性.在盆栽条件下,水分控制在10%左右时,接菌的小麦和对照相比降低了气孔的阻力,提高了叶片气孔传导力,蒸腾速率,有效光合作用和水平利用效率.

  8. ARBUSCULAR MYCORRHIZAL COLONIZATION OF LARREA TRIDENTATA AND AMBROSIA DUMOSA ROOTS VARIES WITH PRECIPITATION AND SEASON IN THE MOJAVE DESERT

    Energy Technology Data Exchange (ETDEWEB)

    M. E. APPLE; C. I. THEE; V. L. SMITH-LONGOZO; C. R. COGAR; C. E. WELLS; R. S. NOWAK

    2004-01-01

    The percentage of fine roots colonized by arbuscular mycorrhizal (AM) fungi varied with season and with species in the co-dominant shrubs Lurreu tridentutu and Ambrosia dumosu at a site adjacent to the Nevada Desert FACE (Free-Air CO{sub 2} Enrichment) Facility (NDFF) in the Mojave Desert. We excavated downward and outward from the shrub bases in both species to collect and examine fine roots (< 1.0 mm diameter) at monthly intervals throughout 2001 and from October 2002 to September 2003. Fungal structures became visible in cleared roots stained with trypan blue. We quantified the percent colonization of roots by AM fungi via the line intercept method. In both years and for both species, colonization was highest in fall, relatively low in spring when root growth began, increased in late spring, and decreased during summer drought periods. Increases in colonization during summer and fall reflect corresponding increases in precipitation. Spring mycorrhizal colonization is low despite peaks in soil water availability and precipitation, indicating that precipitation is not the only factor influencing mycorrhizal colonization. Because the spring decrease in mycorrhizal colonization occurs when these shrubs initiate a major flush of fine root growth, other phenological events such as competing demands for carbon by fine root initiation, early season shoot growth, and flowering may reduce carbon availability to the fungus, and hence decrease colonization. Another possibility is that root growth exceeds the rate of mycorrhizal colonization.

  9. Contrasting preferences of arbuscular mycorrhizal and dark septate fungi colonizing boreal and subarctic Avenella flexuosa.

    Science.gov (United States)

    Kauppinen, M; Raveala, K; Wäli, P R; Ruotsalainen, A L

    2014-04-01

    Arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi are ubiquitous in grass roots, but their colonizations may vary according to latitudinal gradient and site conditions. We investigated how vegetation zone (boreal vs. subarctic), humus thickness, and site openness affect root fungal colonizations of the grass Avenella flexuosa. More precisely, we hypothesized that AM and DSE fungal colonizations would have different responses to environmental conditions such that AM fungi could be more common in boreal zone, whereas we expected DSE fungi to be more affected by the amount of humus. We found site openness to affect AM and DSE fungi in a contrasting manner, in interaction with the vegetation zone. AM colonization was high at open coastal dunes, whereas DSE fungi were more common at forested sites, in the boreal zone. Humus thickness affected AM fungi negatively and DSE fungi positively. To conclude, the observed AM and DSE fungal colonization patterns were largely contrasting. AM fungi were favored in seashore conditions characterized by thin humus layer, whereas DSE fungi were favored in conditions of higher humus availability.

  10. Fresh perspectives on the roles of arbuscular mycorrhizal fungi in plant nutrition and growth.

    Science.gov (United States)

    Smith, Sally E; Smith, F Andrew

    2012-01-01

    Recent research on arbuscular mycorrhizas has demonstrated that AM fungi play a significant role in plant phosphorus (P) uptake, regardless of whether the plant responds positively to colonization in terms of growth or P content. Here we focus particularly on implications of this finding for consideration of the balance between organic carbon (C) use by the fungi and P delivery (i.e. the C-P trade between the symbionts). Positive growth responses to arbuscular mycorrhizal (AM) colonization are attributed frequently to increased P uptake via the fungus, which results in relief of P deficiency and increased growth. Zero AM responses, compared with non-mycorrhizal (NM) plants, have conventionally been attributed to failure of the fungi to deliver P to the plants. Negative responses, combined with excessive C use, have been attributed to this failure. The fungi were viewed as parasites. Demonstration that the AM pathway of P uptake operates in such plants indicates that direct P uptake by the roots is reduced and that the fungi are not parasites but mutualists because they deliver P as well as using C. We suggest that poor plant growth is the result of P deficiency because AM fungi lower the amount of P taken up directly by roots but the AM uptake of P does compensate for the reduction. The implications of interplay between direct root uptake and AM fungal uptake of P also include increased tolerance of AM plants to toxins such as arsenate and increased success when competing with NM plants. Finally we discuss the new information on C-P trade in the context of control of the symbiosis by the fungus or the plant, including new information (from NM plants) on sugar transport and on the role of sucrose in the signaling network involved in responses of plants to P deprivation.

  11. Plant growth depressions in arbuscular mycorrhizal symbioses: not just caused by carbon drain?

    Science.gov (United States)

    Li, Huiying; Smith, F Andrew; Dickson, Sandy; Holloway, Robert E; Smith, Sally E

    2008-01-01

    * This study investigated effects of plant density and arbuscular mycorrhizal (AM) colonization on growth and phosphorus (P) nutrition of a cultivar of wheat (Triticum aestivum) that often shows early AM-induced growth depressions. * Two experiments were conducted. Expt 1 had three plant densities and one soil P concentration. Expt 2 had two plant densities and two P concentrations. Plants were grown in calcareous P-fixing soil, inoculated with Glomus intraradices or Gigaspora margarita, or noninoculated (nonmycorrhizal (NM)). Glomus intraradices colonized well and caused a growth depression only in Expt 1. Gigaspora margarita caused large growth depressions in both experiments even though it colonized poorly. * The results showed that growth depressions were mitigated by changes in relative competition for soil P by NM and AM plants, and probably by decreasing carbon costs of the fungi. * The different effects of the two fungi appear to be attributable to differences in the balance between P uptake by the fungal pathway and direct uptake via the roots. These differences may be important in other AM symbioses that result in growth depressions. The results show that mycorrhizal growth responses of plants grown singly may not apply at the population or community level.

  12. Do arbuscular mycorrhizal fungi affect arsenic accumulation and speciation in rice with different radial oxygen loss?

    Science.gov (United States)

    Li, H; Man, Y B; Ye, Z H; Wu, C; Wu, S C; Wong, M H

    2013-11-15

    The effects of arbuscular mycorrhizal fungi (AMF) on the temporal variation of arsenic (As) speciation and accumulation in two paddy rice cultivars (TD 71 and Xiushui 11) with different degrees of radial oxygen loss (ROL) at three growth periods (day 7, day 35, day 63 after flooding the soil) were investigated in soil, spiked with and without 30 mg As kg(-1). The results showed that TD 71 with high ROL colonized by Glomus intraradices led to higher root colonization rates than Xiushui 11 at three growth periods, both in soil with or without 30 mg As kg(-1) (p<0.05). Mycorrhizal inoculation led to elevated (p<0.05) root ratios of arsenite (As(III)) conc./arsenate (As(V)) conc. (concentration) in TD 71 with high ROL at three growth periods in As contaminated flooding soils. Furthermore, the ratios of As(III) conc./As(V) conc. in roots of TD71 were significantly more than Xiushui 11 when colonized by AMF at three growth periods in 30 mg As kg(-1) soil (p<0.05). Therefore, rice with high ROL can favor AM fungal infection and enhance root ratio of As(III) conc./As(V) conc. in the presence of AMF.

  13. Colonization with Arbuscular Mycorrhizal Fungi Promotes the Growth of Morus alba L. Seedlings under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Nan Lu

    2015-03-01

    Full Text Available Morus alba L. is an important tree species planted widely in China because of its economic value. In this report, we investigated the influence of two arbuscular mycorrhizal fungal (AMF species, Glomus mosseae and Glomus intraradices, alone and together, on the growth of M. alba L. seedlings under greenhouse conditions. The growth parameters and physiological performance of M. alba L. seedlings were evaluated 90 days after colonization with the fungi. The growth and physiological performance of M. alba L. seedlings were significantly affected by the AMF species. The mycorrhizal seedlings were taller, had longer roots, more leaves and a greater biomass than the non-mycorrhizae-treated seedlings. In addition, the AMF species-inoculated seedlings had increased root activity and a higher chlorophyll content compared to non-inoculated seedlings. Furthermore, AMF species colonization increased the phosphorus and nitrogen contents of the seedlings. In addition, simultaneous root colonization by the two AMF species did not improve the growth of M. alba L. seedlings compared with inoculation with either species alone. Based on these results, these AMF species may be applicable to mulberry seedling cultivation.

  14. Arbuscular mycorrhizal fungi from New Caledonian ultramafic soils improve tolerance to nickel of endemic plant species.

    Science.gov (United States)

    Amir, Hamid; Lagrange, Alexandre; Hassaïne, Nadine; Cavaloc, Yvon

    2013-10-01

    In order to improve knowledge about the role of arbuscular mycorrhizal fungi (AMF) in the tolerance to heavy metals in ultramafic soils, the present study investigated the influence of two Glomus etunicatum isolates from New Caledonian ultramafic maquis (shrubland), on nickel tolerance of a model plant species Sorghum vulgare, and of two ultramafic endemic plant species, Alphitonia neocaledonica and Cloezia artensis. In a first step, plants were grown in a greenhouse, on sand with defined concentrations of Ni, to appreciate the effects of the two isolates on the alleviation of Ni toxicity in controlled conditions. In a second step, the influence of the AMF on A. neocaledonica and C. artensis plants grown in a New Caledonian ultramafic soil rich in extractable nickel was investigated. Ni reduced mycorrhizal colonization and sporulation of the fungal isolates, but the symbionts increased plant growth and adaptation of endemic plant species to ultramafic conditions. One of the two G. etunicatum isolates showed a stronger positive effect on plant biomass and phosphorus uptake, and a greater reduction in toxicity symptoms and Ni concentration in roots and shoots. The symbionts seemed to act as a barrier to the absorption of Ni by the plant and reduced root-to-shoot Ni translocation. Results indicate the potential of selected native AMF isolates from ultramafic areas for ecological restoration of such degraded ecosystems.

  15. The potential role of arbuscular mycorrhizal fungi in protecting endangered plants and habitats.

    Science.gov (United States)

    Bothe, Hermann; Turnau, Katarzyna; Regvar, Marjana

    2010-10-01

    Ecosystems worldwide are threatened with the extinction of plants and, at the same time, invasion by new species. Plant invasiveness and loss of species can be caused by similar but opposing pressures on the community structures. Arbuscular mycorrhizal fungi (AMF) can have multiple positive effects on plant growth, productivity, health, and stress relief. Many endangered species live in symbiosis with AMF. However, the list of the International Union for Conservation of Nature and Natural Resources (IUCN Red List of Threatened Species) indicates that the mycorrhizal status of most of the threatened species has not been assessed. Rare plants often occur in specialized and also endangered habitats and might utilize specialized or unique AMF. The specificity of any endangered plant to its AMF population has not been investigated. Because most of the current AMF isolates that are available colonize a broad range of plant species, selected inocula could be used to promote growth of endangered plants before the proper and more effective indigenous AMF are characterized. Application of AMF in field sites to protect endangered plants is hardly feasible due to the complexity of plant community structures and the large amount of fungal inocula needed. Endangered plants could, however, be grown as greenhouse cultures together with appropriate fungi, and, at the relevant developmental stage, they could be re-planted into native sites to prevent extinction and to preserve plant community ecology.

  16. Use of arbuscular mycorrhizal fungi to improve the drought tolerance of Cupressus atlantica G.

    Science.gov (United States)

    Zarik, Lamia; Meddich, Abdelilah; Hijri, Mohamed; Hafidi, Mohamed; Ouhammou, Ahmed; Ouahmane, Lahcen; Duponnois, Robin; Boumezzough, Ali

    2016-01-01

    In this study, we investigated whether indigenous arbuscular mycorrhizal (AM) fungi could improve the tolerance of Cupressus atlantica against water deficit. We tested a gradient of watering regime spanning from 90% to 25% of soil retention capacity of water on mycorhized and non-mycorhized seedlings in pot cultures with sterilized and non-sterilized soils. Our result showed a positive impact of AM fungi on shoot height, stem diameter and biomass as well as on the growth rate. We also observed that inoculation with AM fungi significantly improved uptake of minerals by C. atlantica in both sterilized and non-sterilized soils independently of water regimes. We found that mycorhized plants maintained higher relative water content (RWC) and water potential compared with non-mycorhized plants that were subjected to drought-stress regimes (50% and 25% of soil retention capacity). The contents of proline and of soluble sugars showed that their concentrations decreased in non-mycorhized plants subjected to DS. Superoxide dismutase (SOD) and catalase (CAT) activities also decreased in non-mycorhized plants submitted to DS compared to mycorhized plants. The same pattern was observed by measuring peroxidase (POD) enzyme activity. The results demonstrated that AM fungal inoculation promoted the growth and tolerance of C. atlantica against DS in pot cultures. Therefore, mycorrhizal inoculation could be a potential solution for the conservation and reestablishment of C. atlantica in its natural ecosystem.

  17. 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.

  18. Species richness and spore abundance of arbuscular mycorrhizal fungi across distinct land uses in western Brazilian Amazon.

    Science.gov (United States)

    Stürmer, Sidney Luiz; Siqueira, José Oswaldo

    2011-05-01

    Arbuscular mycorrhizal fungi (AMF) were surveyed for species richness and abundance in sporulation in six distinct land uses in the western Amazon region of Brazil. Areas included mature pristine forest and sites converted to pasture, crops, agroforestry, young and old secondary forest. A total of 61 AMF morphotypes were recovered and 30% of them could not be identified to known species. Fungal communities were dominated by Glomus species but Acaulospora species produced the most abundant sporulation. Acaulospora gedanensis cf., Acaulospora foveata, Acaulospora spinosa, Acaulospora tuberculata, Glomus corymbiforme, Glomus sp15, Scutellospora pellucida, and Archaeospora trappei sporulated in all land use areas. Total spore numbers were highly variable among land uses. Mean species richness in crop, agroforestry, young and old secondary forest sites was twice that in pristine forest and pasture. fungal communities were dominated in all land use areas except young secondary forest by two or three species which accounted for 48% to 63% of all sporulation. Land uses influenced AMF community in (1) frequency of occurrence of sporulating AMF species, (2) mean species diversity, and (3) relative spore abundance. Conversion of pristine forest into distinct land uses does not appear to reduce AMF diversity. Cultural practices adopted in this region maintain a high diversity of arbuscular mycorrhizal fungi.

  19. Interactions between arbuscular mycorrhizal fungi and soil bacteria.

    Science.gov (United States)

    Miransari, Mohammad

    2011-02-01

    The soil environment is interesting and complicated. There are so many interactions taking place in the soil, which determine the properties of soil as a medium for the growth and activities of plants and soil microorganisms. The soil fungi, arbuscular mycorrhiza (AM), are in mutual and beneficial symbiosis with most of the terrestrial plants. AM fungi are continuously interactive with a wide range of soil microorganisms including nonbacterial soil microorganisms, plant growth promoting rhizobacteria, mycorrhiza helper bacteria and deleterious bacteria. Their interactions can have important implications in agriculture. There are some interesting interactions between the AM fungi and soil bacteria including the binding of soil bacteria to the fungal spore, the injection of molecules by bacteria into the fungal spore, the production of volatiles by bacteria and the degradation of fungal cellular wall. Such mechanisms can affect the expression of genes in AM fungi and hence their performance and ecosystem productivity. Hence, consideration of such interactive behavior is of significance. In this review, some of the most important findings regarding the interactions between AM fungi and soil bacteria with some new insights for future research are presented.

  20. 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.

  1. 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.

  2. Augmented growth of long pepper in response to arbuscular mycorrhizal inoculation

    Institute of Scientific and Technical Information of China (English)

    R.K.Singh; P.Gogoi

    2012-01-01

    Arbuscular mycorrhizal (AM) technology is a soil-based fertilization practice for sustainable crop productivity.We evaluated six indigenous Arbuscular mycorrhizal fungi (AMF) strains for their symbiotic response with Piper longum (long pepper),a non-timber forest product holding promise as a commercial crop for its medicinal fruits and roots.Piper saplings were raised in a 10 cm thick sand and soil mix inoculated with various AMF.Under field conditions,plants inoculated with AMF demonstrated better survival (≥80%) than non mycorrhizal plants (58%).Almost all the studied AMF strains increased the plant growth,biomass and nutrient content (N and P) over the uninoculated control.Mycorrhizal inoculation with four AMF species,viz:Glomus fasciculatum,G.clarum,G.etunicatum and G.versiforme greatly enhanced long pepper growth both in the nursery and field conditions.

  3. Micorrizas arbusculares del tipo 'Arum' y 'Paris' y endófitos radicales septados oscuros en Miconia ioneura y Tibouchina paratropica (Melastomataceae 'Arum' and 'Paris' arbuscular mycorrhizal types and dark septate root endophytes in Miconia ioneura and Tibouchina paratropica (Melastomataceae

    Directory of Open Access Journals (Sweden)

    Carlos Urcelay

    2005-12-01

    Full Text Available Se estudió la colonización de las raíces por simbiontes fúngicos en Miconia ioneura y Tibouchina paratropica (Melastomataceae. Se observaron y describen estructuras micorrícicas arbusculares pertenecientes a los tipos 'Paris' (hifas y rulos intracelulares y 'Arum' (hifas intercelulares y arbúsculos. Además se observaron endófitos septados oscuros (hifas y esclerocios. Se registra por primera vez la ocurrencia de ambos tipos micorrícicos arbusculares y de endófitos septados oscuros en raíces de especies pertenecientes a la familia Melastomataceae. Se discuten las implicancias ecológicas y evolutivas de la ocurrencia simultánea de los distintos tipos de colonización micorrícica en raíces de la misma especie.The roots of Miconia ioneura and Tibouchina paratropica (Melastomataceae were studied for fungal symbionts colonization. Typical structures of 'Paris' (intracellular hyphae and coils and 'Arum' (intercellular hyphae and arbuscules arbuscular mycorrhizal types were observed and are described here. Dark septate fungi (hyphae and sclerotia were also observed. The occurrence of both types of arbuscular mycorrhizal colonisation and dark septate fungi in the roots of species belonging to Melastomataceae is reported for the first time. The possible ecological and evolutionary implications of the co-occurrence of these mycorrhizal colonisation types in the same species are discussed.

  4. A dipeptide transporter from the arbuscular mycorrhizal fungus Rhizophagus irregularis is upregulated in the intraradical phase

    Science.gov (United States)

    Belmondo, Simone; Fiorilli, Valentina; Pérez-Tienda, Jacob; Ferrol, Nuria; Marmeisse, Roland; Lanfranco, Luisa

    2014-01-01

    Arbuscular mycorrhizal fungi (AMF), which form an ancient and widespread mutualistic symbiosis with plants, are a crucial but still enigmatic component of the plant micro biome. Nutrient exchange has probably been at the heart of the success of this plant-fungus interaction since the earliest days of plants on land. To characterize genes from the fungal partner involved in nutrient exchange, and presumably important for the functioning of the AM symbiosis, genome-wide transcriptomic data obtained from the AMF Rhizophagus irregularis were exploited. A gene sequence, showing amino acid sequence and transmembrane domains profile similar to members of the PTR2 family of fungal oligopeptide transporters, was identified and called RiPTR2. The functional properties of RiPTR2 were investigated by means of heterologous expression in Saccharomyces cerevisiae mutants defective in either one or both of its di/tripeptide transporter genes PTR2 and DAL5. These assays showed that RiPTR2 can transport dipeptides such as Ala-Leu, Ala-Tyr or Tyr-Ala. From the gene expression analyses it seems that RiPTR2 responds to different environmental clues when the fungus grows inside the root and in the extraradical phase. PMID:25232358

  5. Diversity of rhizosphere soil arbuscular mycorrhizal fungi in various soybean cultivars under different continuous cropping regimes.

    Directory of Open Access Journals (Sweden)

    Weiguang Jie

    Full Text Available Recent studies have shown that continuous cropping in soybean causes substantial changes to the microbial community in rhizosphere soil. In this study, we investigated the effects of continuous cropping for various time periods on the diversity of rhizosphere soil arbuscular mycorrhizal (AM fungi in various soybean cultivars at the branching stage. The soybean cultivars Heinong 37 (an intermediate cultivar, Heinong 44 (a high-fat cultivar and Heinong 48 (a high-protein cultivar were seeded in a field and continuously cropped for two or three years. We analyzed the diversity of rhizosphere soil AM fungi of these soybean plants at the branching stage using morphological and denaturing gradient gel electrophoresis (DGGE techniques. The clustering analysis of unweighted pair-group method with arithmetic averages (UPGMA was then used to investigate the AM fungal community shifts. The results showed that increasing the number of years of continuous cropping can improve the colonization rate of AM fungi in different soybean cultivars at the branching stage. The dominant AM fungi in the experimental fields were Funneliformismosseae and Glomus spp. The number of years of continuous cropping and the soybean cultivar both had obvious effects on the diversity of AM fungi, which was consistent with the results of colonization rate analysis. This study establishes a basis for screening dominant AM fungi of soybean. In addition, the results of this study may be useful for the development of AM fungal inoculants.

  6. Influence of phosphorus application and arbuscular mycorrhizal inoculation on growth, foliar nitrogen mobilization, and phosphorus partitioning in cowpea plants.

    Science.gov (United States)

    Taffouo, Victor Désiré; Ngwene, Benard; Akoa, Amougou; Franken, Philipp

    2014-07-01

    The present study was undertaken to evaluate the effects of phosphorus (P) application and arbuscular mycorrhizal (AM) fungi (Funneliformis mosseae) on growth, foliar nitrogen mobilization, and phosphorus partitioning in cowpea (Vigna unguiculata cv. Vita-5) plants. The experiment was conducted in a greenhouse in pots containing a mixture of vermiculite and sterilized quartz sand. Mycorrhizal and non-mycorrhizal cowpea plants were supplied with three levels of soluble P (0.1 (low P), 0.5 (medium P), or 1.0 mM (high P)).Cowpea plants supplied with low P fertilization showed significantly (p fertilization at both the vegetative and pod-filling stages. P uptake and growth parameters of cowpea plants were positively influenced by mycorrhizal inoculation only in the medium P fertilization treatment at the vegetative stage. Lack of these effects in the other treatments may be linked to either a very low P supply (in the low P treatment at the vegetative stage) or the availability of optimal levels of freely diffusible P in the substrate towards the pod-filling stage due to accumulation with time. The N concentration in leaves of all cowpea plants were lower at the pod-filling stage than at the vegetative stage, presumably as a result of N mobilization from vegetative organs to the developing pods. This was however not influenced by AM fungal inoculation and may be a consequence of the lack of an improved plant P acquisition by the fungus at the pod-filling stage.

  7. Spore development and nuclear inheritance in arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Hijri Mohamed

    2011-02-01

    Full Text Available Abstract Background A conventional tenet of classical genetics is that progeny inherit half their genome from each parent in sexual reproduction instead of the complete genome transferred to each daughter during asexual reproduction. The transmission of hereditary characteristics from parents to their offspring is therefore predictable, although several exceptions are known. Heredity in microorganisms, however, can be very complex, and even unknown as is the case for coenocytic organisms such as Arbuscular Mycorrhizal Fungi (AMF. This group of fungi are plant-root symbionts, ubiquitous in most ecosystems, which reproduce asexually via multinucleate spores for which sexuality has not yet been observed. Results We examined the number of nuclei per spore of four AMF taxa using high Z-resolution live confocal microscopy and found that the number of nuclei was correlated with spore diameter. We show that AMF have the ability, through the establishment of new symbioses, to pass hundreds of nuclei to subsequent generations of multinucleated spores. More importantly, we observed surprising heterogeneity in the number of nuclei among sister spores and show that massive nuclear migration and mitosis are the mechanisms by which AMF spores are formed. We followed spore development of Glomus irregulare from hyphal swelling to spore maturity and found that the spores reached mature size within 30 to 60 days, and that the number of nuclei per spores increased over time. Conclusions We conclude that the spores used for dispersal of AMF contain nuclei with two origins, those that migrate into the spore and those that arise by mitosis in the spore. Therefore, these spores do not represent a stage in the life cycle with a single nucleus, raising the possibility that AMF, unlike all other known eukaryotic organisms, lack the genetic bottleneck of a single-nucleus stage.

  8. 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)

  9. Roles of Arbuscular Mycorrhizas in Plant Phosphorus Nutrition: Interactions between Pathways of Phosphorus Uptake in Arbuscular Mycorrhizal Roots Have Important Implications for Understanding and Manipulating Plant Phosphorus Acquisition

    DEFF Research Database (Denmark)

    Smith, S.E.; Jakobsen, Iver; Grønlund, Mette;

    2011-01-01

    In this Update, we review new findings about the roles of the arbuscular mycorrhizas (mycorrhiza = fungus plus root) in plant growth and phosphorus (P) nutrition. We focus particularly on the function of arbuscular mycorrhizal (AM) symbioses with different outcomes for plant growth (from positive...

  10. 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,

  11. 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 mo

  12. 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.

  13. 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 pi...

  14. Arbuscular mycorrhizal inoculation of peanut in low-fertile tropical soil : I. Host-fungus compatibility

    NARCIS (Netherlands)

    Quilambo, OA; Weissenhorn, I.; Kuiper, P.J C; Stulen, I.

    2005-01-01

    The effects of inoculation with an indigenous Mozambican and a commercial arbuscular mycorrhizal (AM) inoculant on two peanut (Arachis hypogaea L.) cultivars, a traditional, low-yielding Mozambican landrace (Local) and a modern, high-yielding cultivar (Falcon), were tested in a non-sterile and low-f

  15. The effect of turf cutting on plant and arbuscular mycorrhizal spore recolonisation: Implications for heathland restoration

    NARCIS (Netherlands)

    Vergeer, P.; Berg, van den L.J.L.; Baar, J.; Ouborg, N.J.; Roelofs, J.G.M.

    2006-01-01

    In two natural heathland vegetations, we analysed the effect of turf cutting on spore numbers of arbuscular mycorrhizal fungi (AMF). Next to this, we performed a controlled factorial experiment to examine the role of AMF for germination and establishment of Arnica montana in both turf cut and non-tu

  16. Community analysis of arbuscular mycorrhizal fungi associated with Ammophila arenaria in Dutch coastal sand dunes

    NARCIS (Netherlands)

    Kowalchuk, G.A.; De Souza, F.A.; Van Veen, J.A.

    2002-01-01

    A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach for the detection and characterization of arbuscular mycorrhizal fungi (AMF) 18S ribosomal DNA (rDNA) was developed and applied to the study of AMF communities associated with the main sand-stabilizing plant spec

  17. Transcriptome analysis of arbuscular mycorrhizal roots during development of the prepenetration apparatus

    NARCIS (Netherlands)

    Siciliano, V.; Genre, A.; Balestrini, R.; Cappellazzo, G.; Wit, de P.J.G.M.; Bonfante, P.

    2007-01-01

    Information on changes in the plant transcriptome during early interaction with arbuscular mycorrhizal (AM) fungi is still limited since infections are usually not synchronized and plant markers for early stages of colonization are not yet available. A prepenetration apparatus (PPA), organized in ep

  18. Biology, ecology and evolution of the family Gigasporaceae, arbuscular mycorrhizal fungi (Glomeromycota)

    NARCIS (Netherlands)

    Souza, Francisco Adriano de

    2005-01-01

    Research described in this thesis focused on biological, ecological and evolutionary aspects of Arbuscular Mycorrhizal Fungi (AMF), and in particular of the family Gigasporaceae (Gigaspora and Scutellospora, genera). This study had two major objectives. The first objective was to obtain better knowl

  19. Arbuscular mycorrhizal fungi associations of vascular plants confined to river valleys: towards understanding the river corridor plant distribution.

    Science.gov (United States)

    Nobis, Agnieszka; Błaszkowski, Janusz; Zubek, Szymon

    2015-01-01

    The group of river corridor plants (RCP) includes vascular plant species which grow mainly or exclusively in the valleys of large rivers. Despite the long recognized fact that some plant species display a corridor-like distribution pattern in Central Europe, there is still no exhaustive explanation of the mechanisms generating this peculiar distribution. The main goal of this study was therefore to investigate whether arbuscular mycorrhizal fungi (AMF) and fungal root endophytes influence the RCP distribution. Arbuscular mycorrhizae (AM) were observed in 19 out of 33 studied RCP. Dark septate endophytes (DSE) and Olpidium spp. were recorded with low abundance in 15 and 10 plant species, respectively. The spores of AMF were found only in 32% of trap cultures established from the soils collected in the river corridor habitats. In total, six widespread AMF species were identified. Because the percentage of non-mycorrhizal species in the group of RCP is significant and the sites in river corridors are characterized by low AMF species diversity, RCP can be outcompeted outside river valleys by the widespread species that are able to benefit from AM associations in more stable plant-AMF communities in non-river habitats.

  20. Glomus africanum and G. iranicum, two new species of arbuscular mycorrhizal fungi (Glomeromycota).

    Science.gov (United States)

    Błaszkowski, Janusz; Kovács, Gábor M; Balázs, Tímea K; Orlowska, Elzbieta; Sadravi, Mehdi; Wubet, Tesfaye; Buscot, François

    2010-01-01

    Two new arbuscular mycorrhizal fungal species (Glomeromycota) of genus Glomus, G. africanum and G. iranicum, are described and illustrated. Both species formed spores in loose clusters and singly in soil and G. iranicum sometimes inside roots. G. africanum spores are pale yellow to brownish yellow, globose to subglobose, (60-)87(-125) μm diam, sometimes ovoid to irregular, 80-110 x 90-140 μm. The spore wall consists of a semipermanent, hyaline, outer layer and a laminate, smooth, pale yellow to brownish yellow, inner layer, which always is markedly thinner than the outer layer. G. iranicum spores are hyaline to pastel yellow, globose to subglobose, (13-)40(-56) μm diam, rarely egg-shaped, prolate to irregular, 39-54 x 48-65 μm. The spore wall consists of three smooth layers: one mucilaginous, short-lived, hyaline, outermost; one permanent, semirigid, hyaline, middle; and one laminate, hyaline to pastel yellow, innermost. Only the outermost spore wall layer of G. iranicum stains red in Melzer's reagent. In the field G. africanum was associated with roots of five plant species and an unrecognized shrub colonizing maritime sand dunes of two countries in Europe and two in Africa, and G. iranicum was associated with Triticum aestivum cultivated in southwestern Iran. In one-species cultures with Plantago lanceolata as the host plant G. africanum and G. iranicum formed arbuscular mycorrhizae. Phylogenetic analyses of partial SSU sequences of nrDNA placed the two new species in Glomus group A. Both species were distinctly separated from sequences of described Glomus species.

  1. Septoglomus fuscum and S. furcatum, two new species of arbuscular mycorrhizal fungi (Glomeromycota).

    Science.gov (United States)

    Blaszkowski, Janusz; Chwat, Gerard; Kovács, Gábor M; Gáspár, Bence K; Ryszka, Przemyslaw; Orlowska, Elzbieta; Pagano, Marcela C; Araújo, Francisca S; Wubet, Tesfaye; Buscot, François

    2013-01-01

    Two new arbuscular mycorrhizal fungal species, (Glomeromycota) Septoglomus fuscum and S. furcatum, are described and illustrated. Spores of S. fuscum usually occur in loose hypogeous clusters, rarely singly in soil or inside roots, and S. furcatum forms only single spores in soil. Spores of S. fuscum are brownish orange to dark brown, globose to subglobose, (20-)47(-90) μm diam, rarely ovoid, 21-50 × 23-60 μm. Their spore wall consists of a semi-persistent, semi-flexible, orange white to golden yellow, rarely hyaline, outer layer, easily separating from a laminate, smooth, brownish orange to dark brown inner layer. Spores of S. furcatum are reddish brown to dark brown, globose to subglobose, (106-) 138(-167) μm diam, rarely ovoid, 108-127 × 135-160 μm, usually with one subtending hypha that is frequently branched below the spore base, or occasionally with two subtending hyphae located close together. Spore walls consists of a semipermanent, hyaline to light orange outermost layer, a semipermanent, hyaline to golden yellow middle layer, and a laminate, smooth, reddish brown to dark brown innermost layer. None of the spore-wall layers of S. fuscum and S. furcatum stain in Melzer's reagent. In the field, S. fuscum was associated with roots of Arctotheca populifolia colonizing maritime dunes located near Strand in South Africa and S. furcatum was associated with Cordia oncocalyx growing in a dry forest in the Ceará State, Brazil. In single-species cultures with Plantago lanceolata as host plant, S. fuscum and S. furcatum formed arbuscular mycorrhizae. Phylogenetic analyses of the SSU, ITS and LSU nrDNA sequences placed the two new species in genus Septoglomus and both new taxa were separated from described Septoglomus species.

  2. Using molecular biology to study mycorrhizal fungal community ecology: Limits and perspectives.

    Science.gov (United States)

    Chagnon, Pierre-Luc; Bainard, Luke D

    2015-01-01

    Molecular tools have progressively replaced morphological approaches to characterize microbial communities in nature. Arbuscular mycorrhizal (AM) fungi are no exception to this rule. Yet, one challenge posed by these symbionts is that they colonize simultaneously both plant roots and soil, which complicates their detection and quantification. In most studies conducted to date, AM fungal communities have been characterized from roots only, soil only or spores only. Here, we discuss the pitfalls associated to drawing ecological inferences using such datasets. We also conclude by arguing that molecular biology will contribute most to advance knowledge in AM fungal ecology if it is integrated into broader perspectives taking into account the natural history of these organisms. This calls for a better merging of molecular and morphological approaches, and the establishment of intensive, long-term research programs.

  3. Arsenate induces the expression of fungal genes involved in As transport in arbuscular mycorrhiza.

    Science.gov (United States)

    González-Chávez, Ma del Carmen A; Ortega-Larrocea, María del Pilar; Carrillo-González, Rogelio; López-Meyer, Melina; Xoconostle-Cázares, Beatriz; Gomez, Susana K; Harrison, Maria J; Figueroa-López, Alejandro Miguel; Maldonado-Mendoza, Ignacio E

    2011-12-01

    We utilized the two-compartment system to study the effect of arsenic (As) on the expression of the Glomus intraradices high-affinity phosphate transporter GiPT, and the GiArsA gene, a novel protein with a possible putative role as part of an arsenite efflux pump and similar to ArsA ATPase. Our results show that induction of GiPT expression correlates with As(V) uptake in the extra-radical mycelium of G. intraradices. We showed a time-concerted induction of transcript levels first of GiPT, followed by GiArsA, as well as the location of gene expression using laser microdissection of these two genes not only in the extra-radical mycelium but also in arbuscules. This work represents the first report showing the dissection of the molecular players involved in arbuscular mycorrhizal fungus (AMF)-mediated As tolerance in plants, and suggests that tolerance mediated by AMF may be caused by an As exclusion mechanism, where fungal structures such as the extra-radical mycelium and arbuscules may be playing an important role. Our results extend knowledge of the mechanisms underlying As efflux in arbuscular mycorrhizal fungi and mechanisms related to As tolerance.

  4. Substantial nitrogen acquisition by arbuscular mycorrhizal fungi from organic material has implications for N cycling.

    Science.gov (United States)

    Hodge, Angela; Fitter, Alastair H

    2010-08-03

    Arbuscular mycorrhizal (AM) fungi are obligate biotrophs that acquire carbon (C) solely from host plants. AM fungi can proliferate hyphae in, and acquire nitrogen (N) from, organic matter. Although they can transfer some of that N to plants, we tested the hypothesis that organic matter is an important N source for the AM fungi themselves. We grew pairs of plants with and without the AM fungus Glomus hoi in microcosms that allowed only the fungus access to a 15N/13C-labeled organic patch; in some cases, one plant was shaded to reduce C supply to the fungus. The fungal hyphae proliferated vigorously in the patch, irrespective of shading, and increased plant growth and N content; approximately 3% of plant N came from the patch. The extraradical mycelium of the fungus was N-rich (3-5% N) and up to 31% of fungal N came from the patch, confirming the hypothesis. The fungus acquired N as decomposition products, because hyphae were not 13C-enriched. In a second experiment, hyphae of both G. hoi and Glomus mosseae that exploited an organic material patch were also better able to colonize a new host plant, demonstrating a fungal growth response. These findings show that AM fungi can obtain substantial amounts of N from decomposing organic materials and can enhance their fitness as a result. The large biomass and high N demand of AM fungi means that they represent a global N pool equivalent in magnitude to fine roots and play a substantial and hitherto overlooked role in the nitrogen cycle.

  5. Context-dependency of arbuscular mycorrhizal fungi on plant-insect interactions in an agroecosystem

    Directory of Open Access Journals (Sweden)

    Nicholas A Barber

    2013-09-01

    Full Text Available 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 growth. AMF may also have important indirect effects on plants by altering interactions with other community members. By influencing plant traits, AMF can modify aboveground interactions with both mutualists, such as pollinators, and antagonists, such as herbivores. Because herbivory and pollination can dramatically influence plant fitness, comprehensive assessment of plant-AMF interactions should include these indirect effects. To determine how AMF affect plant-insect interactions, we grew Cucumis sativus (Cucurbitaceae under five AMF inoculum treatments and control. We measured plant growth, floral production, flower size, and foliar nutrient content of half the plants, and transferred the other half to a field setting to measure pollinator and herbivore preference of wild insects. Mycorrhizal treatment had no effect on plant biomass or floral traits but significantly affected leaf nutrients, pollinator behavior, and herbivore attack. Although total pollinator visitation did not vary with AMF treatment, pollinators exhibited taxon-specific responses, with honey bees, bumble bees, and Lepidoptera all responding differently to AMF treatments. Flower number and size were unaffected by treatments, suggesting that differences in pollinator preference were driven by other floral traits. Mycorrhizae influenced leaf K and Na, but these differences in leaf nutrients did not correspond to variation in herbivore attack. Overall, we found that AMF indirectly influence both antagonistic and mutualistic insects, but impacts depend on the identity of both the fungal partner and the interacting insect, underscoring the context dependency of plant-AMF interactions.

  6. Species richness of arbuscular mycorrhizal fungi: associations with grassland plant richness and biomass.

    Science.gov (United States)

    Hiiesalu, Inga; Pärtel, Meelis; Davison, John; Gerhold, Pille; Metsis, Madis; Moora, Mari; Öpik, Maarja; Vasar, Martti; Zobel, Martin; Wilson, Scott D

    2014-07-01

    Although experiments show a positive association between vascular plant and arbuscular mycorrhizal fungal (AMF) species richness, evidence from natural ecosystems is scarce. Furthermore, there is little knowledge about how AMF richness varies with belowground plant richness and biomass. We examined relationships among AMF richness, above- and belowground plant richness, and plant root and shoot biomass in a native North American grassland. Root-colonizing AMF richness and belowground plant richness were detected from the same bulk root samples by 454-sequencing of the AMF SSU rRNA and plant trnL genes. In total we detected 63 AMF taxa. Plant richness was 1.5 times greater belowground than aboveground. AMF richness was significantly positively correlated with plant species richness, and more strongly with below- than aboveground plant richness. Belowground plant richness was positively correlated with belowground plant biomass and total plant biomass, whereas aboveground plant richness was positively correlated only with belowground plant biomass. By contrast, AMF richness was negatively correlated with belowground and total plant biomass. Our results indicate that AMF richness and plant belowground richness are more strongly related with each other and with plant community biomass than with the plant aboveground richness measures that have been almost exclusively considered to date.

  7. Root Respiration and Growth in Plantago major as Affected by Vesicular-Arbuscular Mycorrhizal Infection.

    Science.gov (United States)

    Baas, R; van der Werf, A; Lambers, H

    1989-09-01

    Effects of vesicular-arbuscular mycorrhizal (VAM) infection and P on root respiration and dry matter allocation were studied in Plantago major L. ssp. pleiosperma (Pilger). By applying P, the relative growth rate of non-VAM controls and plants colonized by Glomus fasciculatum (Thaxt. sensu Gerdemann) Gerdemann and Trappe was increased to a similar extent (55-67%). However, leaf area ratio was increased more and net assimilation rate per unit leaf area was increased less by VAM infection than by P addition. The lower net assimilation rate could be related to a 20 to 30% higher root respiration rate per unit leaf area of VAM plants. Root respiration per unit dry matter and specific net uptake rates of N and P were increased more by VAM infection than by P addition. Neither the contribution of the alternative respiratory path nor the relative growth rate could account for the differences in root respiration rate between VAM and non-VAM plants. It was estimated that increased fungal respiration (87%) and ion uptake rate (13%) contributed to the higher respiratory activity of VAM roots of P. major.

  8. Wetland dicots and monocots differ in colonization by arbuscular mycorrhizal fungi and dark septate endophytes.

    Science.gov (United States)

    Weishampel, Peter A; Bedford, Barbara L

    2006-10-01

    As an initial step towards evaluating whether mycorrhizas influence composition and diversity in calcareous fen plant communities, we surveyed root colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSE) in 67 plant species in three different fens in central New York State (USA). We found colonization by AMF and DSE in most plant species at all three sites, with the type and extent of colonization differing between monocots and dicots. On average, AMF colonization was higher in dicots (58+/-3%, mean+/-SE) than in monocots (13+/-4%) but DSE colonization followed the opposite trend (24+/-3% in monocots and 9+/-1% in dicots). In sedges and cattails, two monocot families that are often abundant in fens and other wetlands, AMF colonization was usually very low (<10%) in five species and completely absent in seven others. However, DSE colonization in these species was frequently observed. Responses of wetland plants to AMF and DSE are poorly understood, but in the fen communities surveyed, dicots appear to be in a better position to respond to AMF than many of these more abundant monocots (e.g., sedges and cattails). In contrast, these monocots may be more likely to respond to DSE. Future work directed towards understanding the response of these wetland plants to AMF and DSE should provide insight into the roles these fungal symbionts play in influencing diversity in fen plant communities.

  9. Arbuscular mycorrhizal status of wild plants in saline-alkaline soils of the Yellow River Delta.

    Science.gov (United States)

    Wang, Fa-Yuan; Liu, Run-Jin; Lin, Xian-Gui; Zhou, Jian-Min

    2004-04-01

    A survey was made of the arbuscular mycorrhizal (AM) status of five dominant wild plants Tamarix chinensis, Phragmites communis, Suaeda glauca, Aeluropus littoralis var. sinensis and Cirsium setosum in saline-alkaline soils of the Yellow River Delta that show low plant diversity. All of the species were colonized and showed typical AM structures (arbuscules, vesicles). The colonization percentage ranged from 0.2% to 9.5%, where C. setosum was the highest. The species richness of AMF at the different sites ranged from 2.00 to 2.40 per 50 ml soil, with an average of 2.16. Species diversity ranged from 1.99 to 2.22 per 50 ml soil, with an average of 2.13. Spore density ranged from 3 to 30 per 50 ml soil, with an average of 12. Glomus was the dominant genus, with a frequency and relative abundance of 88.1% and 68.4%, respectively. G. caledonium, with a frequency and relative abundance of 15.0% and 4.6%, respectively, was the dominant species. Differences were also observed in the distribution of AMF in different soil layers. Although there were still AM fungal spores in the layer 40 cm below the surface, most spores were found at a depth of 0-40 cm.

  10. Red/Far Red Light Controls Arbuscular Mycorrhizal Colonization via Jasmonic Acid and Strigolactone Signaling.

    Science.gov (United States)

    Nagata, Maki; Yamamoto, Naoya; Shigeyama, Tamaki; Terasawa, Yohei; Anai, Toyoaki; Sakai, Tatsuya; Inada, Sayaka; Arima, Susumu; Hashiguchi, Masatsugu; Akashi, Ryo; Nakayama, Hideyuki; Ueno, Daisuke; Hirsch, Ann M; Suzuki, Akihiro

    2015-11-01

    Establishment of a nitrogen-fixing symbiosis between legumes and rhizobia not only requires sufficient photosynthate, but also the sensing of the ratio of red to far red (R/FR) light. Here, we show that R/FR light sensing also positively influences the arbuscular mycorrhizal (AM) symbiosis of a legume and a non-legume through jasmonic acid (JA) and strigolactone (SL) signaling. The level of AM colonization in high R/FR light-grown tomato and Lotus japonicus significantly increased compared with that determined for low R/FR light-grown plants. Transcripts for JA-related genes were also elevated under high R/FR conditions. The root exudates derived from high R/FR light-grown plants contained more (+)-5-deoxystrigol, an AM-fungal hyphal branching inducer, than those from low R/FR light-grown plants. In summary, high R/FR light changes not only the levels of JA and SL synthesis, but also the composition of plant root exudates released into the rhizosphere, in this way augmenting the AM symbiosis.

  11. Arbuscular mycorrhizal fungi reduce the differences in competitiveness between dominant and subordinate plant species.

    Science.gov (United States)

    Mariotte, Pierre; Meugnier, Claire; Johnson, David; Thébault, Aurélie; Spiegelberger, Thomas; Buttler, Alexandre

    2013-05-01

    In grassland communities, plants can be classified as dominants or subordinates according to their relative abundances, but the factors controlling such distributions remain unclear. Here, we test whether the presence of the arbuscular mycorrhizal (AM) fungus Glomus intraradices affects the competitiveness of two dominant (Taraxacum officinale and Agrostis capillaris) and two subordinate species (Prunella vulgaris and Achillea millefolium). Plants were grown in pots in the presence or absence of the fungus, in monoculture and in mixtures of both species groups with two and four species. In the absence of G. intraradices, dominants were clearly more competitive than subordinates. In inoculated pots, the fungus acted towards the parasitic end of the mutualism-parasitism continuum and had an overall negative effect on the growth of the plant species. However, the negative effects of the AM fungus were more pronounced on dominant species reducing the differences in competitiveness between dominant and subordinate species. The effects of G. intraradices varied with species composition highlighting the importance of plant community to mediate the effects of AM fungi. Dominant species were negatively affected from the AM fungus in mixtures, while subordinates grew identically with and without the fungus. Therefore, our findings predict that the plant dominance hierarchy may flatten out when dominant species are more reduced than subordinate species in an unfavourable AM fungal relationship (parasitism).

  12. Dynamics of arbuscular mycorrhizal symbiosis in heavy metal phytoremediation: Meta-analytical and conceptual perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Audet, Patrick [Ottawa-Carleton Institute of Biology, Department of Biology, University of Ottawa, 30 Marie-Curie Street, Ottawa, ON, K1N 6N5 (Canada)]. E-mail: paude086@uottawa.ca; Charest, Christiane [Ottawa-Carleton Institute of Biology, Department of Biology, University of Ottawa, 30 Marie-Curie Street, Ottawa, ON, K1N 6N5 (Canada)]. E-mail: ccharest@science.uottawa.ca

    2007-06-15

    To estimate dynamics of arbuscular mycorrhizal (AM) symbiosis in heavy metal (HM) phytoremediation, we conducted a literature survey and correlated HM uptake and relative plant growth parameters from published data. After estimating AM feedback responses for these parameters at low and high soil-HM concentration intervals, we determined that the roles of AM symbiosis are characterized by (1) an increased HM phytoextraction via mycorrhizospheric 'Enhanced Uptake' at low soil-HM concentrations, and (2) a reduced HM bioavailability via AM fungal 'Metal-Binding' processes at high soil-HM levels, hence resulting in increased plant biomass and enhanced plant tolerance through HM stress-avoidance. We present two conceptual models which illustrate the important compromise between plant growth, plant HM uptake and HM tolerance, and further emphasize the importance of AM symbiosis in buffering the soil environment for plants under such stress conditions. - This meta-analysis has revealed a transition role of the AM symbiosis in phytoremediation shifting from 'Enhanced Uptake' to 'Metal-Binding' beyond critical soil-HM levels.

  13. Diversity of arbuscular mycorrhizal fungus populations in heavy-metal-contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Del Val, C.; Barea, J.M.; Azcon-Aguilar, C. [CSIC, Granada (Spain)

    1999-02-01

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

  14. Production of Vesicular-Arbuscular Mycorrhizal Fungus Inoculum in Aeroponic Culture †

    Science.gov (United States)

    Hung, Ling-Ling L.; Sylvia, David M.

    1988-01-01

    Bahia grass (Paspalum notatum) and industrial sweet potato (Ipomoea batatas) colonized by Glomus deserticola, G. etunicatum, and G. intraradices were grown in aeroponic cultures. After 12 to 14 weeks, all roots were colonized by the inoculated vesicular-arbuscular mycorrhizal fungi. Abundant vesicles and arbuscules formed in the roots, and profuse sporulation was detected intra-and extraradically. Within each fungal species, industrial sweet potato contained significantly more roots and spores per plant than bahia grass did, although the percent root colonization was similar for both hosts. Mean percent root colonization and sporulation per centimeter of colonized root generally increased with time, although with some treatments colonization declined by week 14. Spore production ranged from 4 spores per cm of colonized root for G. etunicatum to 51 spores per cm for G. intraradices. Infectivity trials with root inocula resulted in a mean of 38, 45, and 28% of bahia grass roots colonized by G. deserticola, G. etunicatum, and G. intraradices, respectively. The germination rate of G. etunicatum spores produced in soil was significantly higher than that produced in aeroponic cultures (64% versus 46%) after a 2-week incubation at 28°C. However, infectivity studies comparing G. etunicatum spores from soil and aeroponic culture indicated no biological differences between the spore sources. Aeroponically produced G. deserticola and G. etunicatum inocula retained their infectivity after cold storage (4°C) in either sterile water or moist vermiculite for at least 4 and 9 months, respectively. PMID:16347548

  15. Arbuscular mycorrhizal fungi differ in their ability to regulate the expression of phosphate transporters in maize (Zea mays L.).

    Science.gov (United States)

    Tian, Hui; Drijber, Rhae A; Li, Xiaolin; Miller, Daniel N; Wienhold, Brian J

    2013-08-01

    Previous studies have found that some phosphate (Pi) starvation inducible transporter genes are downregulated and arbuscular mycorrhizal (AM) inducible Pi transporter genes are upregulated in maize roots associated with the fungus Glomus intraradices. However, little is known about the functional diversity of different AM fungal species in influencing the expression of Pi transporters in maize roots. Here, we studied the expression of two Pi transporter genes ZEAma:Pht1;3 (Pi starvation inducible) and ZEAma:Pht1;6 (AM inducible) in maize root colonized by different AM fungal inoculants. Non-mycorrhizal maize, maize colonized by Glomus deserticola (CA113), Glomus intraradices (IA506), Glomus mosseae (CA201), Gigaspora gigantea (MN922A) and the co-inoculation of all four species were established. The expression patterns of the two genes were quantified using real-time, reverse transcription polymerase chain reaction. The expression level of ZEAma:Pht1;6 was 26-135 times higher in AM plants than in non-mycorrhizal maize roots, whereas the expression level of ZEAma:Pht1;3 was five to 44 times lower in AM plants than in non-mycorrhizal plants. Expression of the two genes differed with inoculation treatment, and increasing the diversity of AM fungi in maize roots led to greater expression of ZEAma:Pht1;6 as well as Pi uptake in shoots. The expression of ZEAma:Pht1;6 was significantly positively correlated with AM colonization rate, concentration of AM biomarkers in maize roots, Pi uptake and dry weight of shoot, but negatively correlated with the expression of ZEAma:Pht1;3. Addition of Pi fertilizer at a low concentration significantly increased the expression of ZEAma:Pht1;6 but had no effect on the expression of ZEAma:Pht1;3.

  16. Arsenic uptake by arbuscular mycorrhizal maize (Zea mays L.) grown in an arsenic-contaminated soil with added phosphorus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As)uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment. Non-mycorrhizal and zero-P addition controls were included. Plant biomass and concentrations and uptake of As, P, and other nutrients, AM colonization, root lengths, and hyphal length densities were determined. The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium. Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments, but shoot and root biomass of AM plants was depressed by P application. AM fungal inoculation decreased shoot As concentrations when no P was added, and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition, respectively. Shoot and root uptake of P, Mn, Cu, and Zn increased, but shoot Fe uptake decreased by 44.6%, with inoculation,when P was added. P addition reduced shoot P, Fe, Mn, Cu, and Zn uptake of AM plants, but increased root Fe and Mn uptake of the nonmycorrhizal ones. AM colonization therefore appeared to enhance plant tolerance to As in low P soil, and have some potential for the phytostabilization of As-contaminated soil, however, P application may introduce additional environmental risk by increasing soil As mobility.

  17. Transcriptomes of arbuscular mycorrhizal fungi and litchi host interaction after tree girdling

    Directory of Open Access Journals (Sweden)

    Bo eShu

    2016-03-01

    Full Text Available Trunk girdling can increase carbohydrate content above the girdling site and is an important strategy for inhibiting new shoot growth to promote flowering in cultivated litchi (Litchi chinenis Sonn.. However, girdling inhibits carbohydrate transport to the root in nearly all of the fruit development periods and consequently decreases root absorption. The mechanism through which carbohydrates regulate root development in arbuscular mycorrhiza (AM remains largely unknown. Carbohydrate content, AM colonization, and transcriptome in the roots were analyzed to elucidate the interaction between host litchi and AM fungi when carbohydrate content decreases. Girdling decreased glucose, fructose, sucrose, quebrachitol and starch contents in the litchi mycorrhizal roots, thereby reducing AM colonization. RNA-seq achieved approximately 60 million reads of each sample, with an average length of reads reaching 100 bp. Assembly of all the reads of the 30 samples produced 671,316 transcripts and 381,429 unigenes, with average lengths of 780 and 643 bp, respectively. Litchi (54,100 unigenes and AM fungi unigenes (33,120 unigenes were achieved through sequence annotation during decreased carbohydrate content. Analysis of differentially expressed genes (DEG showed that flavonoids, alpha-linolenic acid, and linoleic acid are the main factors that regulate AM colonization in litchi. However, flavonoids may play a role in detecting the stage at which carbohydrate content decreases; alpha-linolenic acid or linoleic acid may affect AM formation under the adaptation process. Litchi trees stimulated the expression of defense-related genes and downregulated symbiosis signal-transduction genes to inhibit new AM colonization. Moreover, transcription factors of the AP2, ERF, Myb, WRKY, bHLH families, and lectin genes altered maintenance of litchi mycorrhizal roots in the post-symbiotic stage for carbohydrate starvation. Similar to those of the litchi host, the E3 ubiquitin

  18. Natural selection and the evolutionary ecology of the arbuscular mycorrhizal fungi (Phylum Glomeromycota).

    Science.gov (United States)

    Helgason, Thorunn; Fitter, Alastair H

    2009-01-01

    Darwin's model of evolution by natural selection was based on his observations of change in discrete organisms in which individuals are easy to define. Many of the most abundant functional groups in ecosystems, such as fungi and bacteria, do not fit this paradigm. In this review, we seek to understand how the elegant logic of Darwinian natural selection can be applied to distributed clonal organisms. The arbuscular mycorrhizal (AM) fungi are one such group. Globally, they are ubiquitous in terrestrial ecosystems, are locally distributed among many host plant species, and are significant drivers of nutrient cycling in ecosystems. The AM fungi are intractable to study, as the few taxa that can be cultured cannot be grown in the absence of plant roots. Research has focused on the plant-fungus interface, and thus on the symbiotic phenotype. A model is discussed for the interchange of materials at the interface that throws the emphasis of research onto the behaviour of the individual organisms and removes the need to test for phenomena such as selectivity, co-evolution, and cheating. The AM fungi are distributed organisms with an extensive external mycelium that is likely to be under strong environmental selection. AM fungi show sufficient phenotypic variation and fitness differentials for selection to occur, and developments in genetic analyses suggest that a better understanding of heritability in these organisms is not far away. It is argued that direct selection on fungal traits related to their survival and performance in the soil independent of the host is likely to be the major driver of differentiation in the AM fungi, and the evidence for direct fungal responses to soil conditions such as pH, hypoxia, and temperature is reviewed.

  19. Distribution of arbuscular mycorrhizal fungi associated with different land use systems of Arunachal Pradesh of Eastern Himalayan region.

    Science.gov (United States)

    Bordoloi, A; Nath, P C; Shukla, A K

    2015-10-01

    Arbuscular mycorrhizal fungi are the main component of soil microbial population in most agroecosystems. They forms a close association with more than 80% of the plant species making immobilized mineral nutrients available to the plants in order to sustain normal growth and reproduction. In this study the diversity of mycorrhizal fungi has been examined in seven land use ecosystems of Arunachal Pradesh in Eastern Himalayan region. A total of 24 species of AM fungi belonging to 4 genera viz., Glomus, Scutellospora, Aculospora and Gigaspora were isolated from the soil samples collected from different land use systems. Glomus was the dominant genera and Glomus occulatum was the most abundant species in all the seven land use systems. Total spore number was highly variable among all the land use systems. Species richness was recorded highest in natural forest that maintains a faster nutrient cycle with the highest diversity index. The Jhum fallow land and tea garden has the least number of AM fungal species due to high disturbance of fire and application of fungicides and inorganic fertilizer. Further the plant species composition, particularly the ground vegetation coverage and disturbance level affects the distribution of the AM fungal species. In our study it has been shown that AMF diversity is significantly affected by the land use practices practiced by the people. Hence, the AM fungi isolated from different land use system may be useful in improving the agriculture practices particularly the plantation crops in the region.

  20. Mycorrhizal fungal growth responds to soil characteristics, but not host plant identity, during a primary lacustrine dune succession.

    Science.gov (United States)

    Sikes, Benjamin A; Maherali, Hafiz; Klironomos, John N

    2014-04-01

    Soil factors and host plant identity can both affect the growth and functioning of mycorrhizal fungi. Both components change during primary succession, but it is unknown if their relative importance to mycorrhizas also changes. This research tested how soil type and host plant differences among primary successional stages determine the growth and plant effects of arbuscular mycorrhizal (AM) fungal communities. Mycorrhizal fungal community, plant identity, and soil conditions were manipulated among three stages of a lacustrine sand dune successional series in a fully factorial greenhouse experiment. Late succession AM fungi produced more arbuscules and soil hyphae when grown in late succession soils, although the community was from the same narrow phylogenetic group as those in intermediate succession. AM fungal growth did not differ between host species, and plant growth was similarly unaffected by different AM fungal communities. These results indicate that though ecological filtering and/or adaptation of AM fungi occurs during this primary dune succession, it more strongly reflects matching between fungi and soils, rather than interactions between fungi and host plants. Thus, AM fungal performance during this succession may not depend directly on the sequence of plant community succession.

  1. Effect of inoculation with arbuscular mycorrhizal fungi on the degradation of DEHP in soil

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-guang; LIN Xian-gui; YIN Rui; HOU Yan-lin

    2004-01-01

    The effect of inoculation with arbuscular mycorrhiza(AM) fungi(Acaulospora lavis) on the degradation of di(2-ethylhexyl) phthalate(DEHP) in soil was studies. Cowpea plants(Pigna sinensis) were used as host plants and grown in a specially designed rhizobox. The experimental results indicated that, both in sterile and non-sterile soil, mycorrhizal colonization rates were much higher in the mycorrhizal plants than in the non-mycorrhizal plants. Addition of 4 mg/kg DEHP slightly affected mycorrhizal colonization, but the addition of 100 mg/kg DEHP significantly decreased mycorrhizal colonization. DEHP degradation in the mycorrhizosphere(Ms) and hyphosphere(Hs), especially in the Hs, increased after inoculation with Acaulospora lavis. It is concluded that mycorrhizal hyphae play an important role in the plant uptake, degradation and translocation of DEHP. The mechanism might be attributed to increased numbers of bacteria and actinomycetes and activity of dehydrogenase, urease and acid phosphatase in the Ms and Hs by mycorrhizal fungi.

  2. Arbuscular mycorrhizal colonization improves growth and biochemical profile in Acacia arabica under salt stress

    Directory of Open Access Journals (Sweden)

    Promita Datta

    2014-12-01

    Full Text Available This study elucidated the individual and mixed mycorrhizal effects of two arbuscular mycorrhizal (AM isolates on growth and biochemical status of Acacia arabica under salinity stress gradients. Salt treatment provided in soil hampered legume growth and its biochemical status. But, mycorrhizal colonizations in plant root system reduced the extent of deleterious salt effect and also helped in plant growth enhancement. Additionally, mixed mycorrhizal association (Glomus mosseae + Glomus fasciculatum responded better towards osmolyte accumulation and in salt stress alleviation. Due to individual and mixed mycorrhizal colonizations in A. arabica; protein, carbohydrate and reducing sugar acquisitions were found maximum at soil salinity of 5.94 dS/m over corresponding non-mycorrhizal plant. However, mixed AM inoculation accumulated proline content and improved dry biomass to a higher magnitude at the highest soil salinity level. Mixed AM (G. mosseae + G. fasciculatum colonization improved maximum amount of total chlorophyll (20.94%, protein (19.72%, carbohydrate (23.83%, reducing sugar (17.60% at soil salinity of 5.94 dS/m and dry biomass (20.35%, proline content (10.99% at salinity level of 8.26 dS/m when compared with non-mycorrhizal counterpart. Greater magnitude of AM root colonization was found in mixed AM treated plant and may be responsible for more improvement in growth and biochemical status and consequently mitigated adverse salt effect better.

  3. 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.

  4. Arbuscular mycorrhizal associations in different forest tree species of Hazarikhil forest of Chittagong, Bangladesh

    Institute of Scientific and Technical Information of China (English)

    P.P.Dhar; M.A.U.Mridha

    2012-01-01

    Biodiversity ofarbuscular mycorrhizal (AM) colonization and AM fungal spores were studied in the roots and rhizosphere soils of Acacia catechu (L.f).Wild.,A.mangium Willd,Anthocephala cadamba Miq.,Artocarpus chaplasha Roxb.,Chickrassia tabularis A.Juss.,Swietenia macrophylla King.,Tectona grandis L.from plantations; Albizia procera (Roxb.) Benth.,A.falcataria L.,Alstonia scholaris (L.) R.Br.,Aphanamixis polystachya (Wall.) Parker.,Hydnocarpus kurzii (King.)Warb.,Heynea trijuga Roxb.,Lagerstroemia speciosa (L.) Pers.,Messua ferrea Linn.,Podocarpus nerifolia Don.,Swintonia floribunda Griff.,Syzygium fruticosum (Roxb.) DC.,S.grandis (Wt.) Wal.from forest and nursery seedlings of A.polystachya,A.chaplasha,Gmelina arborea Roxb.and S.cuminii (L.) Skeels from Hazarikhil forest,Chittagong of Bangladesh.Roots were stained in aniline blue and rhizosphere soils were assessed by wet sieving and decanting methods.The range of AM colonization varied significantly from 10%-73% in the plantations samples.Maximum colonization was observed in A.mangium (73%) and minimum colonization was observed in C tabularis (10%).Vesicular colonization was recorded 15%-67% in five plantation tree species.The highest was in A.cadamba (67%) and the lowest was in T.grandis; A.chaplasha and C tabularis showed no vesicular colonization.Arbuscular colonization was recorded 12%-60% in four plantation tree species.The highest was in A.mangium (60%) and the lowest was in A.cadamba.Roots of Artocarpus chaplasha,C tabularis and T.grandis showed no arbuscular colonization.Among 12 forest tree species,nine tree species showed AM colonization.The highest was in A.falcataria (62%) and the lowest was in S.fruticosum (10%).Significant variation in vesicular colonization was recorded in seven forest tree species.The highest was in H.trijuga (52%) and the lowest was in L.speciosa (18%).Hydnocarpus kurzii,M.ferrea,P.nerifolia S.fruticosum and S.grandis showed no vesicular colonization.Arbuscular colonization was

  5. Reduced arbuscular mycorrhizal colonization in tomato ethylene mutants Reduzida formação de micorrízas arbusculares em tomateiros mutantes em etileno

    Directory of Open Access Journals (Sweden)

    Agustin Zsögön

    2008-01-01

    Full Text Available Plant hormones are likely key regulators of arbuscular mycorrhizae (AM development. However, their roles in AM are not well known. Here mutants in five hormone classes introgressed in a single tomato (Lycopersicon esculentum Mill. Syn Solanum lycopersicum L. background (cv. Micro-Tom were used to determine their effects on AM development and the expression of defense-related genes (chitinases and b-1,3-glucanases in roots. Under low P conditions, mutant epinastic (epi and Never ripe (Nr, ethylene overproducer and low sensitivity, respectively, had the intraradical colonization by Glomus clarum highly inhibited, as compared to the control Micro-Tom (MT. No significant alterations in fungal colonization were observed in mutants affecting other hormone classes. Under low P conditions, the steady state levels of transcripts encoding a class I basic chitinase (chi9 were higher in mycorrhizal epi and Nr mutant roots as compared to MT controls. In contrast the steady state levels of a class III acidic b-1,3-glucanase (TomPR-Q'a transcripts in mycorrhizal epi mutant roots were significantly lower than in mycorrhizal MT roots. Root colonization in epi mutants was accompanied by several alterations in fungal morphology, as compared to root colonization in MT controls. The data suggest that ethylene may play an important role in controlling intraradical arbuscular mycorrhizal fungal growth.Os hormônios vegetais são possíveis reguladores chave do desenvolvimento de micorrizas arbusculares (MAS. Contudo, seus papéis em MA são pouco conhecidos. No presente estudo, foram utilizados mutantes em cinco classes hormonais introgredidos em uma única cultivar (cv. Micro-Tom de tomateiro (Lycopersicon esculentum Mill. Syn Solanum lycopersicum L. para determinar seus efeitos no desenvolvimento de MA e expressão de genes relacionados à defesa (quitinases e b-1,3-glucanases em raízes. Sob condição de baixo P, os mutantes epinastic (epi e Never ripe (Nr, os

  6. Characterization of arbuscular mycorrhizal fungus communities of Aquilaria crassna and Tectona grandis roots and soils in Thailand plantations.

    Directory of Open Access Journals (Sweden)

    Amornrat Chaiyasen

    Full Text Available Aquilaria crassna Pierre ex Lec. and Tectona grandis Linn.f. are sources of resin-suffused agarwood and teak timber, respectively. This study investigated arbuscular mycorrhizal (AM fungus community structure in roots and rhizosphere soils of A. crassna and T. grandis from plantations in Thailand to understand whether AM fungal communities present in roots and rhizosphere soils vary with host plant species and study sites. Terminal restriction fragment length polymorphism complemented with clone libraries revealed that AM fungal community composition in A. crassna and T. grandis were similar. A total of 38 distinct terminal restriction fragments (TRFs were found, 31 of which were shared between A. crassna and T. grandis. AM fungal communities in T. grandis samples from different sites were similar, as were those in A. crassna. The estimated average minimum numbers of AM fungal taxa per sample in roots and soils of T. grandis were at least 1.89 vs. 2.55, respectively, and those of A. crassna were 2.85 vs. 2.33 respectively. The TRFs were attributed to Claroideoglomeraceae, Diversisporaceae, Gigasporaceae and Glomeraceae. The Glomeraceae were found to be common in all study sites. Specific AM taxa in roots and soils of T. grandis and A. crassna were not affected by host plant species and sample source (root vs. soil but affected by collecting site. Future inoculum production and utilization efforts can be directed toward the identified symbiotic associates of these valuable tree species to enhance reforestation efforts.

  7. Contrasting impacts of defoliation on root colonization by arbuscular mycorrhizal and dark septate endophytic fungi of Medicago sativa.

    Science.gov (United States)

    Saravesi, K; Ruotsalainen, A L; Cahill, J F

    2014-05-01

    Individual plants typically interact with multiple mutualists and enemies simultaneously. Plant roots encounter both arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi, while the leaves are exposed to herbivores. AMF are usually beneficial symbionts, while the functional role of DSE is largely unknown. Leaf herbivory may have a negative effect on root symbiotic fungi due to decreased carbon availability. However, evidence for this is ambiguous and no inoculation-based experiment on joint effects of herbivory on AM and DSE has been done to date. We investigated how artificial defoliation impacts root colonization by AM (Glomus intraradices) and DSE (Phialocephala fortinii) fungi and growth of Medicago sativa host in a factorial laboratory experiment. Defoliation affected fungi differentially, causing a decrease in arbuscular colonization and a slight increase in DSE-type colonization. However, the presence of one fungal species had no effect on colonization by the other or on plant growth. Defoliation reduced plant biomass, with this effect independent of the fungal treatments. Inoculation by either fungal species reduced root/shoot ratios, with this effect independent of the defoliation treatments. These results suggest AM colonization is limited by host carbon availability, while DSE may benefit from root dieback or exudation associated with defoliation. Reductions in root allocation associated with fungal inoculation combined with a lack of effect of fungi on plant biomass suggest DSE and AMF may be functional equivalent to the plant within this study. Combined, our results indicate different controls of colonization, but no apparent functional consequences between AM and DSE association in plant roots in this experimental setup.

  8. Rhizobacteria Selection to Enhance Spore Germination and Hyphal Length of Arbuscular Mycorrhizal Fungi in Vitro

    OpenAIRE

    Cecep, Hidayat; Dedeh H. Arief; Nurbaity, Ane; Sauman, Jajang

    2013-01-01

    In natural condition, Arbuscular Mycorrhizal Fungi (AMF) are surrounded by bacteria that help fungi symbiosis. The research aimed to get rhizobacteria that can act as Mycorrhiza Helper Bacteria (MHB) had been held at Soil Biology and Biotechnology Laboratory Faculty of Agriculture Unpad from February to March 2012. The experimental design used was completely randomized design with 11 treatments (bo= without rhizobacteria, b1= Pseudomonas diminuta, b2 = Bacillus alvei, b3 = B. mycoides, b4 = P...

  9. Glomus intraradices and Pacispora robiginia, species of arbuscular mycorrhizal fungi (Glomeromycota new for Poland

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2013-12-01

    Full Text Available Morphological characters of spores and mycorrhizae of Glomus intraradices, as well as spores of Pacispora robiginia, arbuscular mycorrhizal fungi of the phylum Glomeromycota, were described and illustrated. Additionally, the known distribution of these species in both Poland and other regions of the world was presented. Both the species were not so far recorded in Poland and this paper is the second report of the finding of P. robiginia in the

  10. Population Biology and Interactions of Arbuscular Mycorrhizal Fungi and Their Benefits in Strawberry Cultivation

    OpenAIRE

    Robinson Boyer, Louisa; East Malling Research

    2014-01-01

    The diversity of arbuscular mycorrhizal fungi (AMF) and relative abundance among species may affect their ecological impact. Species-specific primers for qPCR quantification of Funneliformis geosporus and F.mosseae DNA were developed to quantify their relative abundance for use in studying mixed inocula in roots of strawberry under different conditions of water stress. Co-occupation of the same root by both species was shown to commonly occur but the relative abundance of the two species vari...

  11. Effect of arbuscular mycorrhizal fungi and vermicompost liquid extract on quality of straberry

    OpenAIRE

    Fabián Heriberto Rivera Chávez; Luz Elena Castillejo Álvarez; Gilberto Vázquez Gálvez; M. Valentina Angoa Pérez; Guadalupe Oyoque Salcedo; Hortencia Gabriela Mena Violante

    2012-01-01

    The application of arbuscular mycorrhizal fungi (AMF) and vermicompost is one of the alternatives to agrochemical products, to reach crops yield and quality, reducing costs and environmental damage. In the present study, the effect of applying AMF and vermicompost aquose extract (LV) on strawberry fruit quality, was evaluated. The treatments were: 1)control with water (CTL); 2) fertilized (F); 3) inoculated with AMF (M); 4) with vermicompost aquose extract (LV); 5)inoculated with AMF and fert...

  12. Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd.) Poir from Brazilian semi-arid

    OpenAIRE

    Tancredo Augusto Feitosa de Souza; Susana Rodriguez-Echeverría; Leonaldo Alves de Andrade; Helena Freitas

    2016-01-01

    Abstract Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampl...

  13. Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants.

    Science.gov (United States)

    Fellbaum, Carl R; Mensah, Jerry A; Cloos, Adam J; Strahan, Gary E; Pfeffer, Philip E; Kiers, E Toby; Bücking, Heike

    2014-07-01

    Common mycorrhizal networks (CMNs) of arbuscular mycorrhizal (AM) fungi in the soil simultaneously provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled are unknown. Using radioactive and stable isotopes, we followed the transport of phosphorus (P) and nitrogen (N) in the CMNs of two fungal species to plants that differed in their carbon (C) source strength, and correlated the transport to the expression of mycorrhiza-inducible plant P (MtPt4) and ammonium (1723.m00046) transporters in mycorrhizal roots. AM fungi discriminated between host plants that shared a CMN and preferentially allocated nutrients to high-quality (nonshaded) hosts. However, the fungus also supplied low-quality (shaded) hosts with nutrients and maintained a high colonization rate in these plants. Fungal P transport was correlated to the expression of MtPt4. The expression of the putative ammonium transporter 1723.m00046 was dependent on the fungal nutrient supply and was induced when the CMN had access to N. Biological market theory has emerged as a tool with which the strategic investment of competing partners in trading networks can be studied. Our work demonstrates how fungal partners are able to retain bargaining power, despite being obligately dependent on their hosts.

  14. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest.

    Science.gov (United States)

    Eissenstat, David M; Kucharski, Joshua M; Zadworny, Marcin; Adams, Thomas S; Koide, Roger T

    2015-10-01

    The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich patches differently from species with relatively fine absorptive roots? We measured traits related to nutrient foraging (root morphology and architecture, root proliferation, and mycorrhizal colonization) across six coexisting arbuscular mycorrhizal (AM) temperate tree species with and without nutrient addition. Root traits such as root diameter and specific root length were highly correlated with root branching intensity, with thin-root species having higher branching intensity than thick-root species. In both fertilized and unfertilized soil, species with thin absorptive roots and high branching intensity showed much greater root length and mass proliferation but lower mycorrhizal colonization than species with thick absorptive roots. Across all species, fertilization led to increased root proliferation and reduced mycorrhizal colonization. These results suggest that thin-root species forage more by root proliferation, whereas thick-root species forage more by mycorrhizal fungi. In mineral nutrient-rich patches, AM trees seem to forage more by proliferating roots than by mycorrhizal fungi.

  15. Effectiveness of arbuscular mycorrhizal fungi in phytoremediation of lead- contaminated soil by vetiver grass.

    Science.gov (United States)

    Bahraminia, Mahboobeh; Zarei, Mehdi; Ronaghi, Abdolmajid; Ghasemi-Fasaei, Reza

    2016-01-01

    A greenhouse experiment was conducted to evaluate the effectiveness of arbuscular mycorrhizal (AM) fungi in phytoremediation of lead (Pb)-contaminated soil by vetiver grass. Experiment was a factorial arranged in a completely randomized design. Factors included four Pb levels (50, 200, 400, and 800 mg kg(-1)) as Pb (NO3)2, AM fungi at three levels (non mycorrhizal (NM) control, Rhizophagus intraradices, Glomus versiforme). Shoot and root dry weights (SDW and RDW) decreased as Pb levels increased. Mycorrhizal inoculation increased SDW and RDW compared to NM control. With mycorrhizal inoculation and increasing Pb levels, Pb uptake of shoot and root increased compared to those of NM control. Root colonization increased with mycorrhizal inoculation but decreased as Pb levels increased. Phosphorus concentration and uptake in shoot of plants inoculated with AM fungi was significantly higher than NM control at 200 and 800 mg Pb kg(-1). The Fe concentration, Fe and Mn uptake of shoot in plants inoculated with Rhizophagus intraradices in all levels of Pb were significantly higher than NM control. Mycorrhizal inoculation increased Pb extraction, uptake and translocation efficiencies. Lead translocation factor decreased as Pb levels increased; however inoculation with AM fungi increased Pb translocation.

  16. Effects of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species.

    Science.gov (United States)

    Caglar, S; Akgun, A

    2006-07-01

    The experiment was undertaken to test the efficiency of inoculation of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species used as rootstocks. The stratified Pistacia seeds were inoculated with VAM fungi. The highest rate of inoculated roots was 96.7% in P. khinjuck seedlings with G. clarum and G. etunicatum, 83.3% in P. vera seedlings with G. caledonium and 73.3% in P. terebinthus seedlings with G. caledonium. Mycorrhizal inoculations improved seedling height only in P. terebinthus. Certain mycorrhizal inoculations increased the leaf N, but not P and K contents. Seedlings inoculated with G. caledonium had higher reducing sugar contents. It was concluded that pre-inoculated Pistacia seedlings could have a better growth in the harsh field conditions.

  17. Isolation and phenotypic characterization of Lotus japonicus mutants specifically defective in arbuscular mycorrhizal formation.

    Science.gov (United States)

    Kojima, Tomoko; Saito, Katsuharu; Oba, Hirosuke; Yoshida, Yuma; Terasawa, Junya; Umehara, Yosuke; Suganuma, Norio; Kawaguchi, Masayoshi; Ohtomo, Ryo

    2014-05-01

    Several symbiotic mutants of legume plants defective in nodulation have also been shown to be mutants related to arbuscular mycorrhizal (AM) symbiosis. The origin of the AM symbiosis can be traced back to the early land plants. It has therefore been postulated that the older system of AM symbiosis was partially incorporated into the newer system of legume-rhizobium symbiosis. To unravel the genetic basis of the establishment of AM symbiosis, we screened about 34,000 plants derived from ethyl methanesulfonate (EMS)-mutagenized Lotus japonicus seeds by microscopic observation. As a result, three lines (ME778, ME966 and ME2329) were isolated as AM-specific mutants that exhibit clear AM-defective phenotypes but form normal effective root nodules with rhizobial infection. In the ME2329 mutant, AM fungi spread their hyphae into the intercellular space of the cortex and formed trunk hyphae in the cortical cells, but the development of fine branches in the arbuscules was arrested. The ME2329 mutant carried a nonsense mutation in the STR-homolog gene, implying that the line may be an str mutant in L. japonicus. On the ME778 and ME966 mutant roots, the entry of AM fungal hyphae was blocked between two adjacent epidermal cells. Occasionally, hyphal colonization accompanied by arbuscules was observed in the two mutants. The genes responsible for the ME778 and ME966 mutants were independently located on chromosome 2. These results suggest that the ME778 and ME966 lines are symbiotic mutants involved in the early stage of AM formation in L. japonicus.

  18. Arbuscular mycorrhizal colonization in black poplar roots after defoliation by a non-native and a native insect

    Directory of Open Access Journals (Sweden)

    Zampieri E

    2016-08-01

    Full Text Available A major goal in ecology is to understand how interactions among organisms influence ecosystem services. This work compares the effects of two Lepidoptera defoliators, one non-native (Hyphantria cunea and one native (Lymantria dispar to Europe, on the colonization of black poplar (the Populus nigra clone “Jean Pourtet” roots by an arbuscular mycorrhizal (AM symbiotic fungus (Funneliformis mosseae in a pot experiment. The effects of defoliation have also been assessed on the expression of fungal and plant genes playing a role during symbiosis. Both control and defoliated poplars have shown a low level of mycorrhization. Additionally, neither the non-native nor the native insect seem to strongly affect the AM colonization, at least at the time of observation (eight days from the end of the defoliation. Concerning the gene expression analysis, our results suggest that defoliation does not influence neither the expression of genes coding for a fungal and a plant phosphate transporter nor that of a gene coding for a fungal ATPase, and that there were no differences between defoliation carried out by the non-native and the native insect.

  19. Elemental stoichiometry indicates predominant influence of potassium and phosphorus limitation on arbuscular mycorrhizal symbiosis in acidic soil at high altitude.

    Science.gov (United States)

    Khan, Mohammad Haneef; Meghvansi, Mukesh K; Gupta, Rajeev; Veer, Vijay

    2015-09-15

    The functioning of high-altitude agro-ecosystems is constrained by the harsh environmental conditions, such as low temperatures, acidic soil, and low nutrient supply. It is therefore imperative to investigate the site-specific ecological stoichiometry with respect to AM symbiosis in order to maximize the arbuscular mycorrhizal (AM) benefits for the plants in such ecosystems. Here, we assess the elemental stoichiometry of four Capsicum genotypes grown on acidic soil at high altitude in Arunachal Pradesh, India. Further, we try to identify the predominant resource limitations influencing the symbioses of different Capsicum genotypes with the AM fungi. Foliar and soil elemental stoichiometric relations of Capsicum genotypes were evaluated with arbuscular mycorrhizal (AM) colonization and occurrence under field conditions. AM fungal diversity in rhizosphere, was estimated through PCR-DGGE profiling. Results demonstrated that the symbiotic interaction of various Capsicum genotypes with the AM fungi in acidic soil was not prominent in the study site as evident from the low range of root colonization (21-43.67%). In addition, despite the rich availability of carbon in plant leaves as well as in soil, the carbon-for-phosphorus trade between AMF and plants appeared to be limited. Our results provide strong evidences of predominant influence of the potassium-limitation, in addition to phosphorus-limitation, on AM symbiosis with Capsicum in acidic soil at high altitude. We also conclude that the potassium should be considered in addition to carbon, nitrogen, and phosphorus in further studies investigating the stoichiometric relationships with the AMF symbioses in high altitude agro-ecosystems.

  20. The arbuscular mycorrhizal fungus Glomus mosseae gives contradictory effects on phosphorus and arsenic acquisition by Medicago sativa Linn

    Energy Technology Data Exchange (ETDEWEB)

    Chen Baodong [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Xiao Xueyi [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhu Yongguan [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)]. E-mail: ygzhu@rcees.ac.en; Smith, F. Andrew [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, South Australia 5005 (Australia); Miao Xie, Z. [Department of Environmental Science and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Smith, Sally E. [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, South Australia 5005 (Australia)

    2007-07-01

    Mycorrhizal fungi may play an important role in protecting plants against arsenic (As) contamination. However, little is known about the direct and indirect involvement of arbuscular mycorrhizal fungi (AMF) in detoxification mechanisms. A compartmented pot cultivation system ('cross-pots') is used here to investigate the roles of AMF Glomus mosseae in plant phosphorus (P) and As acquisition by Medicago sativa, and P-As interactions. The results indicate that fungal colonization dramatically increased plant dry weight by a factor of around 6, and also substantially increased both plant P and As contents (i.e. total uptake). Irrespective of P and As addition levels, AM plants had shoot and root P concentrations 2 fold higher, but As concentrations significantly lower, than corresponding uninoculated controls. The decreased shoot As concentrations were largely due to 'dilution effects' that resulted from stimulated growth of AM plants and reduced As partitioning to shoots. The study provides further evidence for the protective effects of AMF on host plants against As contamination, and have uncovered key aspects of underlying mechanisms. The possible application of AMF in remediation practices is discussed.

  1. Seed coating with arbuscular mycorrhizal fungi as an ecotechnologicalapproach for sustainable agricultural production of common wheat (Triticum aestivum L.).

    Science.gov (United States)

    Oliveira, Rui S; Rocha, Inês; Ma, Ying; Vosátka, Miroslav; Freitas, Helena

    2016-01-01

    The exploitation of arbuscular mycorrhizal (AM) fungi has become of great interest in agriculture due to their potential roles in reducing the need for agrochemicals, while improving plant growth and nutrition. Nevertheless, the application of AM fungi by dispersing inocula in granular form to open agricultural fields is not feasible because nontargeted spreading of inocula over large surface areas results in high cost per plant. Seed coating has the potential to significantly reduce the amount of inoculum needed, resulting in cost reduction and increased efficiency. The aim of this study was to assess whether seed coating with AM fungal inoculum is a feasible delivery system for production of common wheat (Triticum aestivum L.). Wheat seeds were coated with inoculum of Rhizophagus irregularis BEG140 and grown under different fertilization conditions: (1) none, (2) partial, or (3) complete. Data indicated that mycorrhizal inoculation via seed coating significantly increased the dry weight of shoot and seed spikes of wheat associated with reduced fertilization. Assessment of nutritional status of wheat showed that plants inoculated with R. irregularis via seed coating displayed enhanced stem concentrations of potassium (K), sulfur (S), and zinc (Zn). There were no significant differences in root colonization between plants conventionally inoculated with R. irregularis in soil and those inoculated via seed coating. Seed coating with AM fungi may be as effective as conventional soil inoculation and may contribute to reduce the utilization of chemical fertilizers. The application of AM via seed coating is proposed as an ecotechnological approach for sustainable agricultural wheat production.

  2. Genome-wide analysis of copper, iron and zinc transporters in the arbuscular mycorrhizal fungus Rhizophagus irregularis

    Science.gov (United States)

    Tamayo, Elisabeth; Gómez-Gallego, Tamara; Azcón-Aguilar, Concepción; Ferrol, Nuria

    2014-01-01

    Arbuscular mycorrhizal fungi (AMF), belonging to the Glomeromycota, are soil microorganisms that establish mutualistic symbioses with the majority of higher plants. The efficient uptake of low mobility mineral nutrients by the fungal symbiont and their further transfer to the plant is a major feature of this symbiosis. Besides improving plant mineral nutrition, AMF can alleviate heavy metal toxicity to their host plants and are able to tolerate high metal concentrations in the soil. Nevertheless, we are far from understanding the key molecular determinants of metal homeostasis in these organisms. To get some insights into these mechanisms, a genome-wide analysis of Cu, Fe and Zn transporters was undertaken, making use of the recently published whole genome of the AMF Rhizophagus irregularis. This in silico analysis allowed identification of 30 open reading frames in the R. irregularis genome, which potentially encode metal transporters. Phylogenetic comparisons with the genomes of a set of reference fungi showed an expansion of some metal transporter families. Analysis of the published transcriptomic profiles of R. irregularis revealed that a set of genes were up-regulated in mycorrhizal roots compared to germinated spores and extraradical mycelium, which suggests that metals are important for plant colonization. PMID:25352857

  3. Arbuscular mycorrhizal fungi native from a Mediterranean saline area enhance maize tolerance to salinity through improved ion homeostasis.

    Science.gov (United States)

    Estrada, Beatriz; Aroca, Ricardo; Maathuis, Frans J M; Barea, José Miguel; Ruiz-Lozano, Juan Manuel

    2013-10-01

    Soil salinity restricts plant growth and productivity. Na(+) represents the major ion causing toxicity because it competes with K(+) for binding sites at the plasma membrane. Inoculation with arbuscular mycorrhizal fungi (AMF) can alleviate salt stress in the host plant through several mechanisms. These may include ion selection during the fungal uptake of nutrients from the soil or during transfer to the host plant. AM benefits could be enhanced when native AMF isolates are used. Thus, we investigated whether native AMF isolated from an area with problems of salinity and desertification can help maize plants to overcome the negative effects of salinity stress better than non-AM plants or plants inoculated with non-native AMF. Results showed that plants inoculated with two out the three native AMF had the highest shoot dry biomass at all salinity levels. Plants inoculated with the three native AMF showed significant increase of K(+) and reduced Na(+) accumulation as compared to non-mycorrhizal plants, concomitantly with higher K(+) /Na(+) ratios in their tissues. For the first time, these effects have been correlated with regulation of ZmAKT2, ZmSOS1 and ZmSKOR genes expression in the roots of maize, contributing to K(+) and Na(+) homeostasis in plants colonized by native AMF.

  4. Genome-wide analysis of copper, iron and zinc transporters in the arbuscular mycorrhizal fungus Rhizophagus irregularis

    Directory of Open Access Journals (Sweden)

    Elisabeth eTamayo

    2014-10-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF, belonging to the Glomeromycota, are soil microorganisms that establish mutualistic symbioses with the majority of higher plants. The efficient uptake of low mobility mineral nutrients by the fungal symbiont and their further transfer to the plant is a major feature of this symbiosis. Besides improving plant mineral nutrition, AMF can alleviate heavy metal toxicity to their host plants and are able to tolerate high metal concentrations in the soil. Nevertheless, we are far from understanding the key molecular determinants of metal homeostasis in these organisms. To get some insights into these mechanisms, a genome-wide analysis of Cu, Fe and Zn transporters was undertaken, making use of the recently published whole genome of the AMF Rhizophagus irregularis. This in silico analysis allowed identification of 30 open reading frames in the R. irregularis genome, which potentially encode metal transporters. Phylogenetic comparisons with the genomes of a set of reference fungi showed an expansion of some metal transporter families. Analysis of the published transcriptomic profiles of R. irregularis revealed that a set of genes were up-regulated in mycorrhizal roots compared to germinated spores and extraradical mycelium, which suggests that metals are important for plant colonization.

  5. Fern-associated arbuscular mycorrhizal fungi are represented by multiple Glomus spp.: do environmental factors influence partner identity?

    Science.gov (United States)

    West, Brittany; Brandt, Jessica; Holstien, Kay; Hill, April; Hill, Malcolm

    2009-06-01

    Symbioses involving arbuscular mycorrhizal fungi (AMF) are among the most important ecological associations for many plant species. The diversity of AMF associated with ferns, however, remains poorly studied. Using recently designed Glomus-specific primers, we surveyed the AMF community associated with ferns from deciduous, broad-leaved second-growth forest habitats at the eastern edge of the piedmont region of central Virginia, USA. Results indicate that this molecular approach may be a useful tool for detecting AMF in ferns compared to traditional techniques based on morphology. Over 30 potential fungal ribotypes were identified from eight fern species using denaturing gradient gel electrophoresis. Fungal ribotypes were found to differ widely in terms of (1) the number of fern partners with which they interact and (2) their relative frequency within each fern. Sequence analysis of fungal isolates from three species of fern indicated that the primers were generally highly specific for Glomus species but some non-target DNA was also amplified. Cloned polymerase chain reaction (PCR) products from Polystichum acrostichoides and Osmunda regalis revealed several phylogenetically distinct Glomus species. A single Glomus species was identified in the cloned PCR products from Botrychium virginianum. These findings challenge the hypothesis that the extent or degree of fern-fungal symbiosis is somehow tied to root complexity. Environmental factors appear to influence the suite of AMF that form partnerships with ferns. Some species of fern from similar habitats associated with dissimilar fungal partners (e.g., P. acrostichoides and Athyrium filix-femina var. asplenioides), whereas others harbored uniform fungal communities (e.g., Asplenium platyneuron). The significance of these data in terms of ecological and evolutionary dynamics of the AMF-fern symbiosis is discussed.

  6. The influence of pre-crop plants on the occurrence of arbuscular mycorrhizal fungi (Glomales and Phialophora graminicola associated with roots of winter XTriticosecale

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-08-01

    Full Text Available The influence of four pre-crop plant species on the occurrence of arbuscular mycorrhizal fungal (AMF, Glomales, Zygomycetes spores, mycorrhizae and Phialophora graminicola (Deacon Walker associated with roots of field-culuvated XTriticosecale Wittmack cv. Malno was investigated. The pre-crop plant species were Hordeum vutgare L., Lupinus luteus L., Pisum sativum L., and Vicia faba v. major Harz. Most spores and species of AMF were found when XTriticosecale was cultivated following P. sativum. Prior cropping with L. luteus caused the occurrence of the lowest number of spores among XTriticosecale roots. Mycorrhizal colonization of XTriticosecale was highest when planted after P. sativum and lowest when grown after L. luteus.

  7. Soil nutritional status, not inoculum identity, primarily determines the effect of arbuscular mycorrhizal fungi on the growth of Knautia arvensis plants.

    Science.gov (United States)

    Doubková, Pavla; Kohout, Petr; Sudová, Radka

    2013-10-01

    Arbuscular mycorrhizal (AM) symbiosis is among the factors contributing to plant survival in serpentine soils characterised by unfavourable physicochemical properties. However, AM fungi show a considerable functional diversity, which is further modified by host plant identity and edaphic conditions. To determine the variability among serpentine AM fungal isolates in their effects on plant growth and nutrition, a greenhouse experiment was conducted involving two serpentine and two non-serpentine populations of Knautia arvensis plants grown in their native substrates. The plants were inoculated with one of the four serpentine AM fungal isolates or with a complex AM fungal community native to the respective plant population. At harvest after 6-month cultivation, intraradical fungal development was assessed, AM fungal taxa established from native fungal communities were determined and plant growth and element uptake evaluated. AM symbiosis significantly improved the performance of all the K. arvensis populations. The extent of mycorrhizal growth promotion was mainly governed by nutritional status of the substrate, while the effect of AM fungal identity was negligible. Inoculation with the native AM fungal communities was not more efficient than inoculation with single AM fungal isolates in any plant population. Contrary to the growth effects, a certain variation among AM fungal isolates was revealed in terms of their effects on plant nutrient uptake, especially P, Mg and Ca, with none of the AM fungi being generally superior in this respect. Regardless of AM symbiosis, K. arvensis populations significantly differed in their relative nutrient accumulation ratios, clearly showing the plant's ability to adapt to nutrient deficiency/excess.

  8. 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.

  9. 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.

  10. 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

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

    Directory of Open Access Journals (Sweden)

    Graziella S Gattai

    2011-09-01

    Full Text Available 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.

  12. Effect of Arbuscular Mycorrhizal Inoculation on Plant Growth and Phthalic Ester Degradation in Two Contaminated Soils

    Institute of Scientific and Technical Information of China (English)

    CHEN Rui-Rui; YIN Rui; LIN Xian-Gui; CAO Zhi-Hong

    2005-01-01

    A 60-day pot experiment was carried out using di-(2-ethylhexyl) phthalate (DEHP) as a typical organic pollutant phthalic ester and cowpea (Vigna sinensis) as the host plant to determine the effect of arbuscular mycorrhizal inoculation on plant growth and degradation of DEHP in two contaminated soils, a yellow-brown soil and a red soil. The air-dried soils were uniformly sprayed with different concentrations of DEHP, inoculated or left uninoculated with an arbuscular mycorrhizal (AM) fungus, and planted with cowpea seeds. After 60 days the positive impact of AM inoculation on the growth of cowpea was more pronounced in the red soil than in the yellow-brown soil, with significantly higher (P < 0.01)mycorrhizal colonization rate, shoot dry weight and total P content in shoot tissues for the red soil. Both in the yellowbrown and red soils, AM inoculation significantly (P < 0.01) reduced shoot DEHP content, implying that AM inoculation could inhibit the uptake and translocation of DEHP from roots to the aboveground parts. However, with AM inoculation no positive contribution to the degradation of DEHP was found.

  13. 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

  14. [Effects of the arbuscular mycorrhizal fungi on environmental phytoremediation in coal mine areas].

    Science.gov (United States)

    Li, Shao-Peng; Bi, Yin-Li; Kong, Wei-Ping; Wang, Jin; Yu, Hai-Yang

    2013-11-01

    To resolve the key environmental problems in coal mine areas of environmental phytoremediation, symbiosis of arbuscular mycorrhizal fungi (AMF) and Amorpha fruticosa was investigated. Effects of AMF on the root growth of Amorpha fruticosa and degenerated soil in coal mining subsidence area were studied. Results showed that after 5 months inoculation, AMF improved the shoot and root growth of Amorpha fruticosa. After inoculation with arbuscular mycorrhiza (AM) for 5 months, the inoculation significantly increased root colonization of Amorpha fruticosa. Total glomalin and easily extractable glomalin were increased significantly in the incubated soil. The content of phosphorus and organic matter were increased in the rhizosphere soil. Population of microorganism increased obviously. All the above results show that their ecological effects are significantly improved. AM would promote rhizosphere soil that will help the sustainability of ecological systems in mining area. It is really of great significance to keep the ecological system stability.

  15. Effect of arbuscular mycorrhizal (AM) fungi on 137Cs uptake by plants grown on different soils.

    Science.gov (United States)

    Vinichuk, M; Mårtensson, A; Ericsson, T; Rosén, K

    2013-01-01

    The potential use of mycorrhiza as a bioremediation agent for soils contaminated by radiocesium was evaluated in a greenhouse experiment. The uptake of (137)Cs by cucumber, perennial ryegrass, and sunflower after inoculation with a commercial arbuscular mycorrhizal (AM) product in soils contaminated with (137)Cs was investigated, with non-mycorrhizal quinoa included as a "reference" plant. The effect of cucumber and ryegrass inoculation with AM fungi on (137)Cs uptake was inconsistent. The effect of AM fungi was most pronounced in sunflower: both plant biomass and (137)Cs uptake increased on loamy sand and loamy soils. The total (137)Cs activity accumulated within AM host sunflower on loamy sand and loamy soils was 2.4 and 3.2-fold higher than in non-inoculated plants. Although the enhanced uptake of (137)Cs by quinoa plants on loamy soil inoculated by the AM fungi was observed, the infection of the fungi to the plants was not confirmed.

  16. 31P NMR for the study of P metabolism and translocation in arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Rasmussen, N.; Lloyd, D.C.; Ratcliffe, R.G.

    2000-01-01

    P-31 nuclear magnetic resonance (NMR) spectroscopy was used to study phosphate (P) metabolism in mycorrhizal and nonmycorrhizal roots of cucumber (Cucumis sativus L) and in external mycelium of the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith. The in vivo NMR method allows...... biological systems to be studied non-invasively and non-destructively. (3)1P NMR experiments provide information about cytoplasmic and vacuolar pH, based on the pH-dependent chemical shifts of the signals arising from the inorganic P (P-i) located in the two compartments. Similarly, the resonances arising...... from alpha, beta and gamma phosphates of nucleoside triphosphates (NTP) and nucleoside diphosphates (NDP) supply knowledge about the metabolic activity and the energetic status of the tissue. In addition, the kinetic behaviour of P uptake and storage can be determined with this method. The (3)1P NMR...

  17. 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

    Two experiments were set up to investigate the influence of soil organic matter on growth of arbuscular mycorrhizal (AM) hyphae and concurrent changes in soil inorganic P, organic P and phosphatase activity. A sandy loam soil was kept for 14 months under two regimes (outdoor where surplus...... differing in organic matter were placed in six parallel hyphal compartments (HC) separated from the RC with a 37 mu m mesh. In the first experiment, using Glomus caledonium, hyphal length densities were measured in the HC after 31 days. Added straw increased hyphal length densities by 34 and 62% for soil...... length density was twice as high in soil with added straw compared to the two other treatments. Mycorrhizal colonization resulted in lower activity of acid phosphatase in the HC for two out of three treatments. Alkaline phosphatase activity was only decreased by mycorrhiza in soil without organic matter...

  18. Arsenic uptake in upland rice inoculated with a combination or single arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Chan, W F; Li, H; Wu, F Y; Wu, S C; Wong, M H

    2013-11-15

    A pot trial was conducted to investigate the role of arbuscular mycorrhizal fungi (AMF) on arsenic (As) uptake of upland rice (Oryza sativa L.) cultivar, Zhonghan 221; where the following 3 species of Glomus geosporum (Gg), G. mosseae (Gm) and G. versiforme (Gv) were applied as single or combined inoculations. In general, Gm significantly enhanced (p63% when grown in As80 soil. There was a significant difference (p 0.01) and total P (r = 0.002, p > 0.01) were observed.

  19. ARBUSCULAR MYCORRHIZAL FUNGI FROM THE RfflZOSPHERES OF SOYBEAN CROPS IN LAMPUNG AND WEST JAVA

    Directory of Open Access Journals (Sweden)

    K. KRAMADIBRATA

    1995-01-01

    Full Text Available The occurrence of arbuscular mycorrhizal (AM fungi in the rhizospheres of field-grown soybean crops in the provinces of Lampung and West Java was examined. Nineteen taxa of AM fungi were identified as follows: Acaulospora delicata, A. Foveata, A. rehmii, A. scrobiculata and A. tuberculata; Gigaspora cf. gigantea and Gigaspora sp. 1; Glomus clavisporum; Glomus cf. fasciculatum, Glomus micro-aggregatum, Glomus sp. 1, Glomus sp. 2, Glomus sp. 3 and Glomus sp. 4; Scutellospora cf. heterogama, Scutellospora cf. pellucida, Scutellospora sp. 1. Scutellospora sp.2. and Scutellospora sp. 3.

  20. GintAMT3 – a Low-Affinity Ammonium Transporter of the Arbuscular Mycorrhizal Rhizophagus irregularis

    Science.gov (United States)

    Calabrese, Silvia; Pérez-Tienda, Jacob; Ellerbeck, Matthias; Arnould, Christine; Chatagnier, Odile; Boller, Thomas; Schüßler, Arthur; Brachmann, Andreas; Wipf, Daniel; Ferrol, Nuria; Courty, Pierre-Emmanuel

    2016-01-01

    Nutrient acquisition and transfer are essential steps in the arbuscular mycorrhizal (AM) symbiosis, which is formed by the majority of land plants. Mineral nutrients are taken up by AM fungi from the soil and transferred to the plant partner. Within the cortical plant root cells the fungal hyphae form tree-like structures (arbuscules) where the nutrients are released to the plant-fungal interface, i.e., to the periarbuscular space, before being taken up by the plant. In exchange, the AM fungi receive carbohydrates from the plant host. Besides the well-studied uptake of phosphorus (P), the uptake and transfer of nitrogen (N) plays a crucial role in this mutualistic interaction. In the AM fungus Rhizophagus irregularis (formerly called Glomus intraradices), two ammonium transporters (AMT) were previously described, namely GintAMT1 and GintAMT2. Here, we report the identification and characterization of a newly identified R. irregularis AMT, GintAMT3. Phylogenetic analyses revealed high sequence similarity to previously identified AM fungal AMTs and a clear separation from other fungal AMTs. Topological analysis indicated GintAMT3 to be a membrane bound pore forming protein, and GFP tagging showed it to be highly expressed in the intraradical mycelium of a fully established AM symbiosis. Expression of GintAMT3 in yeast successfully complemented the yeast AMT triple deletion mutant (MATa ura3 mep1Δ mep2Δ::LEU2 mep3Δ::KanMX2). GintAMT3 is characterized as a low affinity transport system with an apparent Km of 1.8 mM and a Vmax of 240 nmol-1 min-1 108 cells-1, which is regulated by substrate concentration and carbon supply. PMID:27252708

  1. GintAMT3 – a low-affinity ammonium transporter of the arbuscular mycorrhizal Rhizophagus irregularis

    Directory of Open Access Journals (Sweden)

    Silvia eCalabrese

    2016-05-01

    Full Text Available Nutrient acquisition and transfer are essential steps in the arbuscular mycorrhizal (AM symbiosis, which is formed by the majority of land plants. Mineral nutrients are taken up by AM fungi from the soil and transferred to the plant partner. Within the cortical plant root cells the fungal hyphae form tree-like structures (arbuscules where the nutrients are released to the plant-fungal interface, i.e. to the periarbuscular space, before being taken up by the plant. In exchange, the AM fungi receive valuable carbohydrates from the plant host. Besides the well-studied uptake of phosphorus (P, the uptake and transfer of nitrogen (N plays a crucial role in this mutualistic interaction. In the AM fungus Rhizophagus irregularis (formerly called Glomus intraradices, two ammonium transporters (AMT were previously described, namely GintAMT1 and GintAMT2. Here, we report the identification and characterization of a newly identified R. irregularis AMT, GintAMT3. Phylogenetic analyses revealed high sequence similarity to previously identified AM fungal AMTs and a clear separation from other fungal AMTs. Topological analysis indicated GintAMT3 to be a membrane bound pore forming protein, and GFP tagging showed it to be highly expressed in the intraradical mycelium (IRM of a fully established AM symbiosis. Expression of GintAMT3 in yeast successfully complemented the yeast AMT triple deletion mutant (MATa ura3 mep1Δ mep2Δ::LEU2 mep3Δ::KanMX2. GintAMT3 is characterized as a low affinity transport system with an apparent Km of 1.8 mM and a Vmax of 240 nmol-1 min-1 108 cells-1, which is regulated by substrate concentration and carbon supply.

  2. Fungal genes related to calcium homeostasis and signalling are upregulated in symbiotic arbuscular mycorrhiza interactions.

    Science.gov (United States)

    Liu, Yi; Gianinazzi-Pearson, Vivienne; Arnould, Christine; Wipf, Daniel; Zhao, Bin; van Tuinen, Diederik

    2013-01-01

    Fluctuations in intracellular calcium levels generate signalling events and regulate different cellular processes. Whilst the implication of Ca(2+) in plant responses during arbuscular mycorrhiza (AM) interactions is well documented, nothing is known about the regulation or role of this secondary messenger in the fungal symbiont. The spatio-temporal expression pattern of putatively Ca(2+)-related genes of Glomus intraradices BEG141 encoding five proteins involved in membrane transport and one nuclear protein kinase, was investigated during the AM symbiosis. Expression profiles related to successful colonization of host roots were observed in interactions of G. intraradices with roots of wild-type Medicago truncatula (line J5) compared to the mycorrhiza-defective mutant dmi3/Mtsym13. Symbiotic fungal activity was monitored using stearoyl-CoA desaturase and phosphate transporter genes. Laser microdissection based-mapping of fungal gene expression in mycorrhizal root tissues indicated that the Ca(2+)-related genes were differentially upregulated in arbuscules and/or in intercellular hyphae. The spatio-temporal variations in gene expression suggest that the encoded proteins may have different functions in fungal development or function during symbiosis development. Full-length cDNA obtained for two genes with interesting expression profiles confirmed a close similarity with an endoplasmic reticulum P-type ATPase and a Vcx1-like vacuolar Ca(2+) ion transporter functionally characterized in other fungi and involved in the regulation of cell calcium pools. Possible mechanisms are discussed in which Ca(2+)-related proteins G. intraradices BEG141 may play a role in mobilization and perception of the intracellular messenger by the AM fungus during symbiotic interactions with host roots.

  3. The Petunia GRAS Transcription Factor ATA/RAM1 Regulates Symbiotic Gene Expression and Fungal Morphogenesis in Arbuscular Mycorrhiza.

    Science.gov (United States)

    Rich, Mélanie K; Schorderet, Martine; Bapaume, Laure; Falquet, Laurent; Morel, Patrice; Vandenbussche, Michiel; Reinhardt, Didier

    2015-07-01

    Arbuscular mycorrhiza (AM) is a mutual symbiosis that involves a complex symbiotic interface over which nutrients are exchanged between the plant host and the AM fungus. Dozens of genes in the host are required for the establishment and functioning of the interaction, among them nutrient transporters that mediate the uptake of mineral nutrients delivered by the fungal arbuscules. We have isolated in a genetic mutant screen a petunia (Petunia hybrida) Gibberellic Acid Insensitive, Repressor of Gibberellic Acid Insensitive, and Scarecrow (GRAS)-type transcription factor, Atypical Arbuscule (ATA), that acts as the central regulator of AM-related genes and is required for the morphogenesis of arbuscules. Forced mycorrhizal inoculations from neighboring wild-type plants revealed an additional role of ATA in restricting mycorrhizal colonization of the root meristem. The lack of ATA, which represents the ortholog of Required For Arbuscular Mycorrhiza1 in Medicago truncatula, renders the interaction completely ineffective, hence demonstrating the central role of AM-related genes for arbuscule development and function.

  4. The Petunia GRAS Transcription Factor ATA/RAM1 Regulates Symbiotic Gene Expression and Fungal Morphogenesis in Arbuscular Mycorrhiza1

    Science.gov (United States)

    Rich, Mélanie K.

    2015-01-01

    Arbuscular mycorrhiza (AM) is a mutual symbiosis that involves a complex symbiotic interface over which nutrients are exchanged between the plant host and the AM fungus. Dozens of genes in the host are required for the establishment and functioning of the interaction, among them nutrient transporters that mediate the uptake of mineral nutrients delivered by the fungal arbuscules. We have isolated in a genetic mutant screen a petunia (Petunia hybrida) GIBBERELLIC ACID INSENSITIVE, REPRESSOR of GIBBERELLIC ACID INSENSITIVE, and SCARECROW (GRAS)-type transcription factor, ATYPICAL ARBUSCULE (ATA), that acts as the central regulator of AM-related genes and is required for the morphogenesis of arbuscules. Forced mycorrhizal inoculations from neighboring wild-type plants revealed an additional role of ATA in restricting mycorrhizal colonization of the root meristem. The lack of ATA, which represents the ortholog of REQUIRED FOR ARBUSCULAR MYCORRHIZA1 in Medicago truncatula, renders the interaction completely ineffective, hence demonstrating the central role of AM-related genes for arbuscule development and function. PMID:25971550

  5. Action Mechanisms of Arbuscular Mycorrhizal Fungi in Phosphorus Uptake by Capsicum annuum L.

    Institute of Scientific and Technical Information of China (English)

    M. SHARIF; N. CLAASSEN

    2011-01-01

    A pot experiment was conducted to investigate the action mechanisms of arbuscular mycorrhizal (AM) fungi in phosphorus (P) uptake of Capsicum annuum L.in a sterilized fossil Oxisol. Three P levels of 0,10 and 200 mg kg-1 soil (P0,P10 and P200,respectively) without and with AM fungal inoculation were applied as Ca(H2PO4)2·H2O.Shoot dry matter yields and shoot P uptake increased significantly (P > 0.05) by the inoculation of AM fungi at P0 and P10.Root length and P concentration in soil solution increased with the inoculation of AM fungi but the root:shoot ratio decreased or remained constant.Around 50% roots of inoculated plants were infected by AM and the external hyphae amounted to 20 m g-1 soil at P10 and P200.The hyphae surface area of the infected root cylinder amounted to 11 and 2 cm2 cm-2 root at P0 and P10,respectively.The increased P uptake of inoculated plants was mainly because of an up to 5 times higher P influx of the infected root.Model calculations showed that the root alone could not have achieved the measured P influx in both infected and non-infected roots.But the P influx for hyphae calculated by the model was even much higher than the measured one.The P uptake capacity of hyphae introduced in the model was too high.Model calculations further showed that the depletion zone around roots or hyphae was very narrow.In the case of the root only 7% of the soil volume would contribute P to the plant,while in the case of hyphae it would be 100%.The results together with the model calculations showed that the increased P uptake of AM inoculated plants could be explained partly by the increased P concentration in the soil solution and by the increased P absorbing surface area coming from the external hyphae.

  6. The effect of agricultural practices on the development of indigenous arbuscular mycorrhizal fungi. II. Studies in experimental microcorms

    NARCIS (Netherlands)

    Boddington, C.L.; Dodd, J.C.

    2000-01-01

    Two glasshouse experiments were performed to assess the development and metabolic activity of mycorrhizas formed by isolates of arbuscular mycorrhizal fungi (AMF) from three different genera, Acaulospora, Gigaspora and Glomus on Desmodium ovalifolium L. plants. In the first experiment the effect of

  7. Nonredundant Regulation of Rice Arbuscular Mycorrhizal Symbiosis by Two Members of the Phosphate Transporter 1 Gene Family

    DEFF Research Database (Denmark)

    Yang, Shu-Yi; Grønlund, Mette; Jakobsen, Iver;

    2012-01-01

    Pi acquisition of crops via arbuscular mycorrhizal (AM) symbiosis is becoming increasingly important due to limited highgrade rock Pi reserves and a demand for environmentally sustainable agriculture. Here, we show that 70% of the overall Pi acquired by rice (Oryza sativa) is delivered via the sy...

  8. Distribution of dominant arbuscular mycorrhizal fungi among five plant species in undisturbed vegetation of a coastal grassland

    DEFF Research Database (Denmark)

    Holtgrewe-Stukenbrock, Eva; Rosendahl, Søren

    2005-01-01

    Most plant species in mixed grassland vegetation are colonized by arbuscular mycorrhizal (AM) fungi. Previous studies have reported differences in host preferences among AM fungi, although the fungi are known to lack host specificity. In the present study, the distribution of phylogenetic groups ...

  9. 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

    Transport of N by hyphae of a vesicular-arbuscular mycorrhizal fungus was studied under controlled experimental conditions. The N source was applied to the soil as (NH4+)-N-15 or (NH3-)N-15. Cucumis sativus was grown for 25 days, either alone or in symbiosis with Glomus intraradices, in containers...

  10. Arbuscular mycorrhizal association enhances drought tolerance potential of promising bioenergy grass (Saccharum arundinaceum retz.).

    Science.gov (United States)

    Mirshad, P P; Puthur, Jos T

    2016-07-01

    The influence of arbuscular mycorrhizal fungi (AMF) (Glomus spp.) on some physiological and biochemical characteristics of bioenergy grass Saccharum arundinaceum subjected to drought stress was studied. The symbiotic association of Glomus spp. was established with S. arundinaceum, a potential bioenergy grass as evident from the increase in percentage of root infection and distribution frequency of vesicles when compared with non-arbuscular mycorrhizal plants. AMF-treated plants exhibited an enhanced accumulation of osmolytes such as sugars and proline and also increased protein content under drought. AMF association significantly increased the accumulation of non-enzymatic antioxidants like phenols, ascorbate and glutathione as well as enhanced the activities of antioxidant enzymes such as SOD (superoxide dismutase), APX (ascorbate peroxidase) and GPX (guaiacol peroxidase) resulting in reduced lipid peroxidation in S. arundinaceum. AMF symbiosis also ameliorated the drought-induced reduction of total chlorophyll content and activities of photosystem I and II. The maximum quantum efficiency of PS II (F v/F m) and potential photochemical efficiency (F v/F o) were higher in AMF plants as compared to non-AMF plants under drought stress. These results indicate that AMF association alleviate drought stress in S. arundinaceum by the accumulation of osmolytes and non-enzymatic antioxidants and enhanced activities of antioxidant enzymes, and hence, the photosynthetic efficiency is improved resulting in increased biomass production. AMF association with energy grasses also improves the acclimatization of S. arundinaceum for growing in marginal lands of drought-affected soils.

  11. Soil bacteria respond to presence of roots but not to mycelium of arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Olsson, P.A.; Bååth, E.; Jakobsen, I.;

    1996-01-01

    Arbuscular mycorrhizal (AM) cucumber seedlings and uncolonized controls were grown in growth chambers which allowed separation of compartments with roots from compartments with the extraradical mycelium alone. Two fungi, Glomus invermaium Hall and G. caledonium (Nicol. and Gerd.) Trappe and Gerde......Arbuscular mycorrhizal (AM) cucumber seedlings and uncolonized controls were grown in growth chambers which allowed separation of compartments with roots from compartments with the extraradical mycelium alone. Two fungi, Glomus invermaium Hall and G. caledonium (Nicol. and Gerd.) Trappe...... and Gerdemann, were used. Bacterial numbers (direct and viable count) and activities (thymidine incorporation) were highest in the root compartment, but were not affected by the AM mycelium after 30 days of plant growth. The soil was stored after harvest for 16 d at 13°C to study the effect of disconnected......) pattern. The bacteria specific PLFAs cy17:0 and cy19:0 increased in both experiments in the root compartments. The PLFAs 15:0 and 17:0, which are usually considered to be bacteria specific, also increased due to the presence of roots, but it was shown that these fatty acids were present in aseptically...

  12. Intraradical colonization by arbuscular mycorrhizal fungi triggers induction of a lipochitooligosaccharide receptor

    Science.gov (United States)

    Rasmussen, S. R.; Füchtbauer, W.; Novero, M.; Volpe, V.; Malkov, N.; Genre, A.; Bonfante, P.; Stougaard, J.; Radutoiu, S.

    2016-07-01

    Functional divergence of paralogs following gene duplication is one of the mechanisms leading to evolution of novel pathways and traits. Here we show that divergence of Lys11 and Nfr5 LysM receptor kinase paralogs of Lotus japonicus has affected their specificity for lipochitooligosaccharides (LCOs) decorations, while the innate capacity to recognize and induce a downstream signalling after perception of rhizobial LCOs (Nod factors) was maintained. Regardless of this conserved ability, Lys11 was found neither expressed, nor essential during nitrogen-fixing symbiosis, providing an explanation for the determinant role of Nfr5 gene during Lotus-rhizobia interaction. Lys11 was expressed in root cortex cells associated with intraradical colonizing arbuscular mycorrhizal fungi. Detailed analyses of lys11 single and nfr1nfr5lys11 triple mutants revealed a functional arbuscular mycorrhizal symbiosis, indicating that Lys11 alone, or its possible shared function with the Nod factor receptors is not essential for the presymbiotic phases of AM symbiosis. Hence, both subfunctionalization and specialization appear to have shaped the function of these paralogs where Lys11 acts as an AM-inducible gene, possibly to fine-tune later stages of this interaction.

  13. Influences of agricultural management practices on Arbuscular Mycorrhiza Fungal symbioses in Kenyan agro-ecosystems

    NARCIS (Netherlands)

    Muriithi-Muchane, M.N.

    2013-01-01

    Conservation agriculture (CA) and integrated soil fertility management (ISFM) practices are receiving increased attention as pathways to sustainable high-production agriculture in sub-Saharan Africa. However, little is known about the effects of these practices on arbuscular mycorrhizal fungi (AMF).

  14. Impact of soil salinity on arbuscular mycorrhizal fungi biodiversity and microflora biomass associated with Tamarix articulata Vahll rhizosphere in arid and semi-arid Algerian areas.

    Science.gov (United States)

    Bencherif, Karima; Boutekrabt, Ammar; Fontaine, Joël; Laruelle, Fréderic; Dalpè, Yolande; Sahraoui, Anissa Lounès-Hadj

    2015-11-15

    Soil salinization is an increasingly important problem in many parts of the world, particularly under arid and semi-arid areas. Unfortunately, the knowledge about restoration of salt affected ecosystems using mycorrhizae is limited. The current study aims to investigate the impact of salinity on the microbial richness of the halophytic plant Tamarix articulata rhizosphere. Soil samples were collected from natural sites with increasing salinity (1.82-4.95 ds.m(-1)). Six arbuscular mycorrhizal fungi (AMF) species were isolated from the different saline soils and identified as Septoglomus constrictum, Funneliformis mosseae, Funneliformis geosporum, Funneliformis coronatum, Rhizophagus fasciculatus, and Gigaspora gigantea. The number of AMF spores increased with soil salinity. Total root colonization rate decreased from 65 to 16% but remained possible with soil salinity. Microbial biomass in T. articulata rhizosphere was affected by salinity. The phospholipid fatty acids (PLFA) C16:1ω5 as well as i15:0, a15:0, i16:0, i17:0, a17:0, cy17:0, C18:1ω7 and cy19:0 increased in high saline soils suggesting that AMF and bacterial biomasses increased with salinity. In contrast, ergosterol amount was negatively correlated with soil salinity indicating that ectomycorrhizal and saprotrophic fungal biomasses were reduced with salinity. Our findings highlight the adaptation of arbuscular and bacterial communities to natural soil salinity and thus the potential use of mycorrhizal T. articulata trees as an approach to restore moderately saline disturbed arid lands.

  15. 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.

  16. Mosaic genome of endobacteria in arbuscular mycorrhizal fungi: Transkingdom gene transfer in an ancient mycoplasma-fungus association.

    Science.gov (United States)

    Torres-Cortés, Gloria; Ghignone, Stefano; Bonfante, Paola; Schüßler, Arthur

    2015-06-23

    For more than 450 million years, arbuscular mycorrhizal fungi (AMF) have formed intimate, mutualistic symbioses with the vast majority of land plants and are major drivers in almost all terrestrial ecosystems. The obligate plant-symbiotic AMF host additional symbionts, so-called Mollicutes-related endobacteria (MRE). To uncover putative functional roles of these widespread but yet enigmatic MRE, we sequenced the genome of DhMRE living in the AMF Dentiscutata heterogama. Multilocus phylogenetic analyses showed that MRE form a previously unidentified lineage sister to the hominis group of Mycoplasma species. DhMRE possesses a strongly reduced metabolic capacity with 55% of the proteins having unknown function, which reflects unique adaptations to an intracellular lifestyle. We found evidence for transkingdom gene transfer between MRE and their AMF host. At least 27 annotated DhMRE proteins show similarities to nuclear-encoded proteins of the AMF Rhizophagus irregularis, which itself lacks MRE. Nuclear-encoded homologs could moreover be identified for another AMF, Gigaspora margarita, and surprisingly, also the non-AMF Mortierella verticillata. Our data indicate a possible origin of the MRE-fungus association in ancestors of the Glomeromycota and Mucoromycotina. The DhMRE genome encodes an arsenal of putative regulatory proteins with eukaryotic-like domains, some of them encoded in putative genomic islands. MRE are highly interesting candidates to study the evolution and interactions between an ancient, obligate endosymbiotic prokaryote with its obligate plant-symbiotic fungal host. Our data moreover may be used for further targeted searches for ancient effector-like proteins that may be key components in the regulation of the arbuscular mycorrhiza symbiosis.

  17. Effects of micronutrients deficiency and inoculation with arbuscular mycorrhizal fungi on chelator exudation by tomato root

    Directory of Open Access Journals (Sweden)

    E. Shirmohammadi

    2010-12-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF can affect their host plants growth through nutrient uptake enhancement. Determination of chelators (siderophores and phytosiderophores in root leachates is of importance in order to account for the effects of AMF on nutrient uptake by plants. In this study, tomato plants were inoculated with either Glomus intraradices or Glomus etunicatum or left un-inoculated as non-mycorrhizal control, in pots containing sterile and acid washed perlite. Rorison’s nutrient solution harbouring three levels of Fe, Mn, Zn and Cu (full strength, half strength and without micronutrients was applied to the pots during three month- growth period. Root leachates were collected and total chelator concentration was quantified by titration with DTPA. Plant roots showed lower mycorrhizal colonization in this condition. The amounts of chelators produced by roots were significantly different in AMF species. In plants inoculated with G. intraradices, the highest chelator production occurred in the absence of micronutrients and in its half strength as well, but the micronutrient levels had no significant effect on chelator production in plants inoculated with G. etunicatum. In the absence of micronutrients, chelator production was higher in G.intraradices inoculated plants compared to the G. etunicatum ones.

  18. Communities of arbuscular mycorrhizal fungi detected in forest soil are spatially heterogeneous but do not vary throughout the growing season.

    Science.gov (United States)

    Davison, John; Öpik, Maarja; Zobel, Martin; Vasar, Martti; Metsis, Madis; Moora, Mari

    2012-01-01

    Despite the important ecosystem role played by arbuscular mycorrhizal fungi (AMF), little is known about spatial and temporal variation in soil AMF communities. We used pyrosequencing to characterise AMF communities in soil samples (n = 44) from a natural forest ecosystem. Fungal taxa were identified by BLAST matching of reads against the MaarjAM database of AMF SSU rRNA gene diversity. Sub-sampling within our dataset and experimental shortening of a set of long reads indicated that our approaches to taxonomic identification and diversity analysis were robust to variations in pyrosequencing read length and numbers of reads per sample. Different forest plots (each 10 × 10 m and separated from one another by 30 m) contained significantly different soil AMF communities, and the pairwise similarity of communities decreased with distance up to 50 m. However, there were no significant changes in community composition between different time points in the growing season (May-September). Spatial structure in soil AMF communities may be related to the heterogeneous vegetation of the natural forest study system, while the temporal stability of communities suggests that AMF in soil represent a fairly constant local species pool from which mycorrhizae form and disband during the season.

  19. Inoculation of somatic embryos of sweet potato with an arbuscular mycorrhizal fungus improves embryo survival and plantlet formation.

    Science.gov (United States)

    Bressan, W; de Carvalho, C H; Sylvia, D M

    2000-08-01

    Responses of somatic embryos of sweet potato (Ipomoea batata (L.) Poir., cv. White Star) at different developmental stages to in vitro inoculation with Glomus etunicatum (Becker and Gerdemann) (isolate INVAM FL329) were evaluated. Somatic embryos were grown in glass tubes containing sterilized vermiculite and sand. A layer of natrosol plus White's medium was used as a carrier for arbuscular mycorrhizal (AM) fungal spores. Survival of embryos inoculated with AM fungi was significantly (P < 0.05) greater than that of noninoculated embryos at the rooted-cotyledonary-torpedo and rooted-elongated-torpedo developmental stages. Mycorrhizae significantly (P < 0.05) increased plantlet formation only when inoculation occurred at the rooted-elongated-torpedo developmental stage. The growth stage at which the embryos were inserted into the glass tubes exerted a significant influence upon plantlet formation, and plantlet formation was further enhanced by inoculation with G. etunicatum. Plantlet formation was greatest at the rooted-elongated-torpedo stage. These results demonstrate that inoculation of somatic embryos with AM fungi improves embryo survival and plantlet formation, and could enhance use of somatic embryos as synthetic seeds.

  20. Radioactivity and the environment: technical approaches to understand the role of arbuscular mycorrhizal plants in radionuclide bioaccumulation

    Directory of Open Access Journals (Sweden)

    Helena S. Davies

    2015-07-01

    Full Text Available Phytoaccumulation of radionuclides is of significant interest with regards to monitoring radionuclide build-up in food chains, developing methods for environmental bioremediation and for ecological management. There are many gaps in our understanding of the characteristics and mechanisms of plant radionuclide accumulation, including the importance of symbiotically-associated arbuscular mycorrhizal (AM fungi. We first briefly review the evidence that demonstrates the ability of AM fungi to enhance the translocation of 238U into plant root tissues, and how fungal association may prevent further mobilization into shoot tissues. We then focus on approaches that should further advance our knowledge of AM fungi-plant radionuclide accumulation. Current research has mostly used artificial cultivation methods and we consider how more ecologically-relevant analysis might be performed. The use of synchrotron-based X-ray fluorescence imaging and absorption spectroscopy techniques to understand the mechanisms of radionuclide transfer from soil to plant via AM fungi is evaluated. Without such further knowledge, the behavior and mobilization of radionuclides cannot be accurately modelled and the potential risks cannot be accurately predicted.

  1. Sex-specific interaction between arbuscular mycorrhizal and dark septate fungi in the dioecious plant Antennaria dioica (Asteraceae).

    Science.gov (United States)

    Vega-Frutis, R; Varga, S; Kytöviita, M-M

    2013-05-01

    Male and female plants of dioecious species often differ in their resource demands and this has been linked to secondary sexual dimorphism, including sex-specific interactions with other organisms such as herbivores and pollinators. However, little is known about the interaction between dioecious plants and fungal root endophytes. Plants may be simultaneously colonised by arbuscular mycorrhizal (AM) and dark septate (DS) fungi. While it is well established that AM mutualism involves reciprocal transfer of photosynthates and mineral nutrients between roots of host plants and these fungi, the role of DS fungi remains controversial. Here, we report the temporal and spatial variation in AM and DS fungi in female, male and non-reproductive Antennaria dioica plants in three natural populations in Finland during flowering and after seed production. Females had higher colonisation by AM fungi, but lower colonisation by DS fungi than male and non-reproductive plants. The higher AM colonisation was observed during flowering, and this difference varied among populations. Our results suggest that females and males of A. dioica interact with AM and DS fungi differently and that this relationship is dependent on soil fertility.

  2. The effects of triclosan on spore germination and hyphal growth of the arbuscular mycorrhizal fungus Glomus intraradices.

    Science.gov (United States)

    Twanabasu, Bishnu R; Stevens, Kevin J; Venables, Barney J

    2013-06-01

    The effect of triclosan (5-chloro-2-[2,4-dichlorophenoxy]phenol; TCS), on spore germination, hyphal growth, and hyphal branching of the arbuscular mycorrhizal (AM) fungus, Glomus intraradices spores was evaluated at exposure concentrations of 0.4 and 4.0 μg/L in a static renewal exposure system. To determine if potential effects were mycotoxic or a consequence of impaired signaling between a host plant and the fungal symbiont, spores were incubated with and without the addition of a root exudate. Exposed spores were harvested at days 7, 14, and 21. AM spore germination, hyphal growth, and hyphal branching were significantly lower in both TCS concentrations compared to controls in non-root exudate treatments suggesting direct mycotoxic effects of TCS on AM development. Greater hyphal growth and hyphal branching in controls and 0.4μg/L TCS treatments with root exudate compared to non-root exudate treatments demonstrated growth stimulation by signaling chemicals present in the root exudate. This stimulatory effect was absent in the 4.0 μg/L TCS treatments indicating a direct effect on plant signaling compounds or plant signal response.

  3. Effect of vegetation types on soil arbuscular mycorrhizal fungi and nitrogen-fixing bacterial communities in a karst region.

    Science.gov (United States)

    Liang, Yueming; Pan, Fujing; He, Xunyang; Chen, Xiangbi; Su, Yirong

    2016-09-01

    Arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria play important roles in plant growth and recovery in degraded ecosystems. The desertification in karst regions has become more severe in recent decades. Evaluation of the fungal and bacterial diversity of such regions during vegetation restoration is required for effective protection and restoration in these regions. Therefore, we analyzed relationships among AM fungi and nitrogen-fixing bacteria abundances, plant species diversity, and soil properties in four typical ecosystems of vegetation restoration (tussock (TK), shrub (SB), secondary forest (SF), and primary forest (PF)) in a karst region of southwest China. Abundance of AM fungi and nitrogen-fixing bacteria, plant species diversity, and soil nutrient levels increased from the tussock to the primary forest. The AM fungus, nitrogen-fixing bacterium, and plant community composition differed significantly between vegetation types (p fungi and nitrogen-fixing bacteria, respectively. Available phosphorus, total nitrogen, and soil organic carbon levels and plant richness were positively correlated with the abundance of AM fungi and nitrogen-fixing bacteria (p fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration.

  4. Sequencing and comparison of the mitochondrial COI gene from isolates of Arbuscular Mycorrhizal Fungi belonging to Gigasporaceae and Glomeraceae families.

    Science.gov (United States)

    Borriello, Roberto; Bianciotto, Valeria; Orgiazzi, Alberto; Lumini, Erica; Bergero, Roberta

    2014-06-01

    Arbuscular Mycorrhizal Fungi (AMF) are well known for their ecological importance and their positive influence on plants. The genetics and phylogeny of this group of fungi have long been debated. Nuclear markers are the main tools used for phylogenetic analyses, but they have sometimes proved difficult to use because of their extreme variability. Therefore, the attention of researchers has been moving towards other genomic markers, in particular those from the mitochondrial DNA. In this study, 46 sequences of different AMF isolates belonging to two main clades Gigasporaceae and Glomeraceae have been obtained from the mitochondrial gene coding for the Cytochrome c Oxidase I (COI), representing the largest dataset to date of AMF COI sequences. A very low level of divergence was recorded in the COI sequences from the Gigasporaceae, which could reflect either a slow rate of evolution or a more recent evolutionary divergence of this group. On the other hand, the COI sequence divergence between Gigasporaceae and Glomeraceae was high, with synonymous divergence reaching saturated levels. This work also showed the difficulty in developing valuable mitochondrial markers able to effectively distinguish all Glomeromycota species, especially those belonging to Gigasporaceae, yet it represents a first step towards the development of a full mtDNA-based dataset which can be used for further phylogenetic investigations of this fungal phylum.

  5. The Medicago truncatula Sucrose Transporter Family: Characterization and Implication of Key Members in Carbon Partitioning towards Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    Joan Doidy; Diederik van Tuinen; Olivier Lamotte; Marion Corneillat; Gérard Alcaraz; Daniel Wipf

    2012-01-01

    We identified de novo sucrose transporter (SUT) genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula.The identification and functional analysis of sugar transporters provide key information on mechanisms that underlie carbon partitioning in plant-microorganism interactions.In that way,full-length sequences of the M.truncatula SUT (MtSUT)family were retrieved and biochemical characterization of MtSUT members was performed by heterologous expression in yeast.The MtSUT family now comprises six genes which distribute among Dicotyledonous clades.MtSUT1-1 and MtSUT4-1 are key members in regard to their expression profiles in source leaves and sink roots and were characterized as functional H+/sucrose transporters.Physiological and molecular responses to phosphorus supply and inoculation by the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied by gene expression and sugar quantification analyses.Sucrose represents the main sugar transport form in M.truncatula and the expression profiles of MtSUT1-1,MtSUT2,and MtSUT4-1 highlight a fine-tuning regulation for beneficial sugar fluxes towards the fungal symbiont.Taken together,these results suggest distinct functions for proteins from the SUT1,SUT2,and SUT4 clades in plant and in biotrophic interactions.

  6. Communities of arbuscular mycorrhizal fungi detected in forest soil are spatially heterogeneous but do not vary throughout the growing season.

    Directory of Open Access Journals (Sweden)

    John Davison

    Full Text Available Despite the important ecosystem role played by arbuscular mycorrhizal fungi (AMF, little is known about spatial and temporal variation in soil AMF communities. We used pyrosequencing to characterise AMF communities in soil samples (n = 44 from a natural forest ecosystem. Fungal taxa were identified by BLAST matching of reads against the MaarjAM database of AMF SSU rRNA gene diversity. Sub-sampling within our dataset and experimental shortening of a set of long reads indicated that our approaches to taxonomic identification and diversity analysis were robust to variations in pyrosequencing read length and numbers of reads per sample. Different forest plots (each 10 × 10 m and separated from one another by 30 m contained significantly different soil AMF communities, and the pairwise similarity of communities decreased with distance up to 50 m. However, there were no significant changes in community composition between different time points in the growing season (May-September. Spatial structure in soil AMF communities may be related to the heterogeneous vegetation of the natural forest study system, while the temporal stability of communities suggests that AMF in soil represent a fairly constant local species pool from which mycorrhizae form and disband during the season.

  7. Effects of Soil Depth and Season Variation on Community Structure of Arbuscular Mycorrhizal Fungi in Greenhouse Soils Planted with Watermelon

    Institute of Scientific and Technical Information of China (English)

    LIU Run-Jin; LI Yan; DIAO Zhi-Kai; LI Min; LIN Xian-Gui

    2013-01-01

    The characteristics of arbuscular mycorrhizal fungal (AMF) community structure in various soil depths and growing seasons of watermelon (Citrullus vulgaris) grown in commercial greenhouses in Daxing of Beijing and Weifang and Laiyang of Shandong,China were investigated using both morphological identification and denaturing gradient gel electrophoresis.The sampled soils had been used for continuous greenhouse production of watermelon for 0,5,10,15,or 20 years.Glomus claroideum was the dominant species in the greenhouse soils planted for 5,10,and 15 years in Laiyang,while Glomus mosseae and Glomus etunicatum were dominant in the nearby open farmland soil.Sorenson's similarity index of AMF community composition ranged from 0.67 to 0.84 in the soils planted for 5 years,and from 0.29 to 0.33 for 20 years among the three locations.Spore abundance,species richness,and the Shannon index were highest near the soil surface (0-10 cm) and decreased with soil depth,and higher in June and October than in August and December.Canonical correspondence analysis showed that available P and the number of years that soil had been used for greenhouse production were the main factors contributing to the variance of AMF community composition.It was concluded that the community structure of AMF was mainly influenced by soil available P and planting time of watermelon as well as by soil depth and seasonal variation in the commercial greenhouse.

  8. Two putative-aquaporin genes are differentially expressed during arbuscular mycorrhizal symbiosis in Lotus japonicus

    Directory of Open Access Journals (Sweden)

    Giovannetti Marco

    2012-10-01

    Full Text Available Abstract 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.

  9. 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.

  10. Effect of Arbuscular Mycorrhizal Fungi on Growth and Antioxidant Activity in Gmelina arborea Roxb. under Salt Stress Condition

    Directory of Open Access Journals (Sweden)

    Mayura Prakash DUDHANE

    2011-11-01

    Full Text Available Gmelina arborea Roxb. is medicinally and economically important tree species were selected for study. An experiment was conducted to determine the influence of arbuscular mycorrhizal (AM fungus Glomus fasciculatum on salt stress tolerance of tree species Gmelina arborea. Mycorrhizal and nonmycorrhizal seedlings were treated with 100 mM and 200 mM concentration of NaCl. G. fasciculatum treated plant showed increase in fresh and dry weight, greater percentage of mycorrhizal colonization, higher accumulation of proline and chlorophyll content with increasing levels of salinity. G. fasciculatum colonization significantly increased tolerance of salinity, acid phosphatases, and Proline content and also antioxidant enzymes like peroxidase, catalase and superoxide dismutase at all levels of salinity treatments of Gmelina plants in comparison with non-mycorrhizal salinity treated plants. These results demonstrate that AM fungus (G. fasciculatum is very effective in strengthening the tolerance of Gmelina arborea grown in arid and semi arid areas.

  11. Arbuscular mycorrhizal colonization alters subcellular distribution and chemical forms of cadmium in Medicago sativa L. and resists cadmium toxicity.

    Science.gov (United States)

    Wang, Yuanpeng; Huang, Jing; Gao, Yanzheng

    2012-01-01

    Some plants can tolerate and even detoxify soils contaminated with heavy metals. This detoxification ability may depend on what chemical forms of metals are taken up by plants and how the plants distribute the toxins in their tissues. This, in turn, may have an important impact on phytoremediation. We investigated the impact of arbuscular mycorrhizal (AM) fungus, Glomus intraradices, on the subcellular distribution and chemical forms of cadmium (Cd) in alfalfa (Medicago sativa L.) that were grown in Cd-added soils. The fungus significantly colonized alfalfa roots by day 25 after planting. Colonization of alfalfa by G. intraradices in soils contaminated with Cd ranged from 17% to 69% after 25-60 days and then decreased to 43%. The biomass of plant shoots with AM fungi showed significant 1.7-fold increases compared to no AM fungi addition under the treatment of 20 mg kg(-1) Cd. Concentrations of Cd in the shoots of alfalfa under 0.5, 5, and 20 mgkg(-1) Cd without AM fungal inoculation are 1.87, 2.92, and 2.38 times higher, respectively, than those of fungi-inoculated plants. Fungal inoculation increased Cd (37.2-80.5%) in the cell walls of roots and shoots and decreased in membranes after 80 days of incubation compared to untreated plants. The proportion of the inactive forms of Cd in roots was higher in fungi-treated plants than in controls. Furthermore, although fungi-treated plants had less overall Cd in subcellular fragments in shoots, they had more inactive Cd in shoots than did control plants. These results provide a basis for further research on plant-microbe symbioses in soils contaminated with heavy metals, which may potentially help us develop management regimes for phytoremediation.

  12. Changes in the diversity of soil arbuscular mycorrhizal fungi after cultivation for biofuel production in a Guantanamo (Cuba tropical system.

    Directory of Open Access Journals (Sweden)

    Maria del Mar Alguacil

    Full Text Available The arbuscular mycorrhizal fungi (AMF are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba, in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems.

  13. Changes in the diversity of soil arbuscular mycorrhizal fungi after cultivation for biofuel production in a Guantanamo (Cuba) tropical system.

    Science.gov (United States)

    Alguacil, Maria del Mar; Torrecillas, Emma; Hernández, Guillermina; Roldán, Antonio

    2012-01-01

    The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity) were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare) did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C) were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems.

  14. Changes in the Diversity of Soil Arbuscular Mycorrhizal Fungi after Cultivation for Biofuel Production in a Guantanamo (Cuba) Tropical System

    Science.gov (United States)

    Alguacil, Maria del Mar; Torrecillas, Emma; Hernández, Guillermina; Roldán, Antonio

    2012-01-01

    The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity) were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare) did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C) were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems. PMID:22536339

  15. Arbuscular mycorrhizal colonization alters subcellular distribution and chemical forms of cadmium in Medicago sativa L. and resists cadmium toxicity.

    Directory of Open Access Journals (Sweden)

    Yuanpeng Wang

    Full Text Available Some plants can tolerate and even detoxify soils contaminated with heavy metals. This detoxification ability may depend on what chemical forms of metals are taken up by plants and how the plants distribute the toxins in their tissues. This, in turn, may have an important impact on phytoremediation. We investigated the impact of arbuscular mycorrhizal (AM fungus, Glomus intraradices, on the subcellular distribution and chemical forms of cadmium (Cd in alfalfa (Medicago sativa L. that were grown in Cd-added soils. The fungus significantly colonized alfalfa roots by day 25 after planting. Colonization of alfalfa by G. intraradices in soils contaminated with Cd ranged from 17% to 69% after 25-60 days and then decreased to 43%. The biomass of plant shoots with AM fungi showed significant 1.7-fold increases compared to no AM fungi addition under the treatment of 20 mg kg(-1 Cd. Concentrations of Cd in the shoots of alfalfa under 0.5, 5, and 20 mgkg(-1 Cd without AM fungal inoculation are 1.87, 2.92, and 2.38 times higher, respectively, than those of fungi-inoculated plants. Fungal inoculation increased Cd (37.2-80.5% in the cell walls of roots and shoots and decreased in membranes after 80 days of incubation compared to untreated plants. The proportion of the inactive forms of Cd in roots was higher in fungi-treated plants than in controls. Furthermore, although fungi-treated plants had less overall Cd in subcellular fragments in shoots, they had more inactive Cd in shoots than did control plants. These results provide a basis for further research on plant-microbe symbioses in soils contaminated with heavy metals, which may potentially help us develop management regimes for phytoremediation.

  16. Development and amplification of multiple co-dominant genetic markers from single spores of arbuscular mycorrhizal fungi by nested multiplex PCR

    DEFF Research Database (Denmark)

    Holtgrewe-Stukenbrock, Eva; Rosendahl, Søren

    2005-01-01

    marker was amplified separately in nested PCR using specific primers. Polymorphic loci within the three putative single copy genes GmFOX2, GmTOR2, and GmGIN1 were characterized by sequencing and single strand conformation polymorphisms (SSCP). Primers specific for the LSU rDNA D2 region were included......Multiple co-dominant genetic markers from single spores of the arbuscular mycorrhizal (AM) fungi Glomus mosseae, Glomus caledonium, and Glomus geosporum were amplified by nested multiplex PCR using a combination of primers for simultaneous amplification of five loci in one PCR. Subsequently, each...... in the multiplex PCR to ensure correct identification of the Glomus spp. spores. Single AM fungal spores were characterized as multilocus genotypes by combining alleles of each amplified locus. Only one copy of each putative single copy gene could be amplified from each spore, indicating that spores...

  17. Phosphorus effects on the mycelium and storage structures of an arbuscular mycorrhizal fungus as studied in the soil and roots by analysis of fatty acid signatures

    DEFF Research Database (Denmark)

    Olsson, P.A.; Bååth, E.; Jakobsen, I.

    1997-01-01

    in the extraradical mycelium was positively correlated with the level of root infection and thus decreased with increasing applications of P. The neutral lipid/phospholipid ratio indicated that at high P levels, less carbon was allocated to storage structures. At all levels of P applied, the major part of the AM......The distribution of an arbuscular mycorrhizal (AM) fungus between soil and roots, and between mycelial and storage structures, was studied by use of the fatty acid signature 16:1 omega 5. Increasing the soil phosphorus level resulted in a decrease in the level of the fatty acid 16:1 omega 5...... in the soil and roots. A similar decrease was detected by microscopic measurements of root colonization and of the length of AM fungal hyphae in the soil. The fatty acid 16:1 omega 5 was estimated from two types of lipids, phospholipids and neutral lipids, which mainly represent membrane lipids and storage...

  18. Effect of Carbon and Nitrogen Availability on Metabolism of Amino Acids in Germinating Spores of Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    JIN Hai-Ru; JIANG Dong-Hua; ZHANG Ping-Hua

    2011-01-01

    The effects of carbon (C) and nitrogen (N) sources on N utilization and biosynthesis of amino acids were examined in the germinating spores of the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith after exposure to various N substrates,CO2,glucose,and/or root exudates.The N uptake and de novo biosynthesis of amino acids were analyzed using stable isotopic labeling with mass spectrometric detection.High-performance liquid chromatography-based analysis was used to measure amino acid levels.In the absence of exogenous N sources and in the presence of 25 mL L-1 CO2,the germinating AM fungal spores utilized internal N storage as well as C skeletons derived from the degradation of storage lipids to biosynthesize the free amino acids,in which serine and glycine were produced predominantly.The concentrations of internal amino acids increased gradually as the germination time increased from 0 to 1 or 2 weeks.However,asparagine and glutamine declined to the low levels; both degraded to provide the biosynthesis of other amino acids with C and N donors.The availability of exogenous inorganic N (ammonium and nitrate) and organic N (urea,arginine,and glutamine) to the AM fungal spores using only CO2 for germination generated more than 5 times more internal free amino acids than those in the absence of exogenous N.A supply of exogenous nitrate to the AM fungal spores with only CO2 gave rise to more than 10 times more asparagine than that without exogenous N.In contrast,the extra supply of exogenous glucose to the AM fungal spores generated a significant enhancement in the uptake of exogenous N sources,with more than 3 times more free amino acids being produced than those supplied with only exogenous CO2.Meanwhile,arginine was the most abundant free amino acid produced and it was incorporated into the proteins of AM fungal spores to serve as an N storage compound.

  19. The PAM1 gene of petunia, required for intracellular accommodation and morphogenesis of arbuscular mycorrhizal fungi, encodes a homologue of VAPYRIN.

    Science.gov (United States)

    Feddermann, Nadja; Muni, Rajasekhara Reddy Duvvuru; Zeier, Tatyana; Stuurman, Jeroen; Ercolin, Flavia; Schorderet, Martine; Reinhardt, Didier

    2010-11-01

    Most terrestrial plants engage into arbuscular mycorrhizal (AM) symbiosis with fungi of the phylum Glomeromycota. The initial recognition of the fungal symbiont results in the activation of a symbiosis signalling pathway that is shared with the root nodule symbiosis (common SYM pathway). The subsequent intracellular accommodation of the fungus, and the elaboration of its characteristic feeding structures, the arbuscules, depends on a genetic programme in the plant that has recently been shown to involve the VAPYRIN gene in Medicaco truncatula. We have previously identified a mutant in Petunia hybrida, penetration and arbuscule morphogenesis 1 (pam1), that is defective in the intracellular stages of AM development. Here, we report on the cloning of PAM1, which encodes a VAPYRIN homologue. PAM1 protein localizes to the cytosol and the nucleus, with a prominent affinity to mobile spherical structures that are associated with the tonoplast, and are therefore referred to as tonospheres. In mycorrhizal roots, tonospheres were observed in the vicinity of intracellular hyphae, where they may play an essential role in the accommodation and morphogenesis of the fungal endosymbiont.

  20. Mycorrhizal-like interaction between gametophytes and young sporophytes of the fern Dryopteris muenchii (Filicales) and its fungal endophyte.

    Science.gov (United States)

    Reyes-Jaramillo, Irma; Camargo-Ricalde, Sara Lucía; Aquiahuatl-Ramos, Ma de los Angeles

    2008-09-01

    The morphology of a Glomus-like fungus-host interaction in chlorophyllous gametophytes and young apogamic sporophytes of Dryopteris muenchii A.R. Sm. was studied from ferns cultivated in laboratory, using soil as substrate. An aseptate fungus colonized the gametophytes' tissue through the rhizoids, developing vesicles. The fungus penetrated the young sporophytes primary roots by developing appressoria. It spread forming inter- and intra-cellular hyphae through the epidermis and the outermost cortical cell layers, where it formed vesicles, hyphal coils-like and arbuscules. The fungus hyphae never colonized the gametophyte-sporophyte cellular junction. The fungal structures observed on D. muenchii during this study, are rather similar to those reported for the plant host-arbuscular mycorrhizal fungus (AMF) interaction, where the AMF described belonged to Phylum Glomeromycota. Therefore, this study is a contribution to the scarce knowledgement of the association between AMF and chlorophyllous gametophytes and young apogamic sporophytes of ferns.

  1. Enhanced N-Transfer from a Soybean to Maize by Vesicular Arbuscular Mycorrhizal (VAM) Fungi 1

    Science.gov (United States)

    van Kessel, Christopher; Singleton, Paul W.; Hoben, Heinz J.

    1985-01-01

    Using a split-root technique, roots of soybean plants were divided between two pots. In one of the two pots, two maize plants were grown and half of those pots were inoculated with the vesicular arbuscular mycorrhizal (VAM) fungus, Glomus fasciculatus. Fifty-two days after planting, 15N-labeled ammonium sulfate was applied to the pots which contained only soybean roots. Forty-eight hours after application, significantly higher values for atom per cent 15N excess were found in roots and leaves of VAM-infected maize plants as compared with the non-VAM-infected maize plants. Results indicated that VAM fungi did enhance N transfer from one plant to another. Images Fig. 1 PMID:16664451

  2. Enhanced N-Transfer from a Soybean to Maize by Vesicular Arbuscular Mycorrhizal (VAM) Fungi.

    Science.gov (United States)

    van Kessel, C; Singleton, P W; Hoben, H J

    1985-10-01

    Using a split-root technique, roots of soybean plants were divided between two pots. In one of the two pots, two maize plants were grown and half of those pots were inoculated with the vesicular arbuscular mycorrhizal (VAM) fungus, Glomus fasciculatus. Fifty-two days after planting, (15)N-labeled ammonium sulfate was applied to the pots which contained only soybean roots. Forty-eight hours after application, significantly higher values for atom per cent (15)N excess were found in roots and leaves of VAM-infected maize plants as compared with the non-VAM-infected maize plants. Results indicated that VAM fungi did enhance N transfer from one plant to another.

  3. Glomus claroideum and G. spurcum, arbuscular mycorrhizal fungi (Glomeromycota new for Poland and Europe, respectively

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2011-01-01

    Full Text Available The ontogenetic development and morphological properties of spores of two species of arbuscular mycorrhizal fungi (Glomeromycota of the genus Glomus, G. claroideum and G. spurcum, are described and illustrated. Spores of the two species were not earlier found in Poland, and this paper is the first report of the occurrence of G. spurcum in Europe. In one-species pot cultures with Plantago lanceolata as the host plant, the mycorrhizae of G. claroideum consist of arbuscules, vesicles, as well as intra- and extraradical hyphae staining intensively with trypan blue. Glomus spurcum mycorrhizae were not recognized, because many attempts to establish one-species cultures of this fungus failed. Additionally, the distribution of both the fungi in the world is presented.

  4. Community Structures of Arbuscular Mycorrhizal Fungi in Soils and Plant Roots Inhabiting Abandoned Mines of Korea

    Science.gov (United States)

    Park, Hyeok; Lee, Eun-Hwa; Ka, Kang-Hyeon

    2016-01-01

    In this study, we collected rhizosphere soils and root samples from a post-mining area and a natural forest area in Jecheon, Korea. We extracted spores of arbuscular mycorrhizal fungi (AMF) from rhizospheres, and then examined the sequences of 18S rDNA genes of the AMF from the collected roots of plants. We compared the AMF communities in the post-mining area and the natural forest area by sequence analysis of the AMF spores from soils and of the AMF clones from roots. Consequently, we confirmed that the structure of AMF communities varied between the post-mining area and the natural forest area and showed significant relationship with heavy metal contents in soils. These results suggest that heavy metal contamination by mining activity significantly affects the AMF community structure. PMID:28154485

  5. A critical review on the nutrition role of arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Omid Alizadeh

    2012-06-01

    Full Text Available Even though many factors influence the accession of mineral nutrients required for plantgrowth, arbuscular mycorrhizal-roots can greatly enhance the accession of mineral nutrients in hostplants. The nutrients enhanced most by AM are those that are of low mobility or sparingly soluble. Withother factors being equal in specific environments, AM may be the difference between whether plants willsurvive and/or have the ability to obtain the required mineral nutrients for sustainability. Although themost commonly reported mineral nutrient enhanced in host plants with AM-roots is P, accession of manyother mineral nutrients (e.g., Zn, Cu, N, S, Ca, Mg, K may be enhanced in plants by AM. Severalreviews about accession of mineral nutrients in AM plants have been published fairly recently. Some ofthe concepts mentioned with P accession may be applicable to the other mineral nutrients. This reviewgives an overview on the role of mycorrhizae in nutrition.

  6. Arbuscular mycorrhizal formation of crucifer leaf mustard induced by flavonoids apigenin and daidzein

    Institute of Scientific and Technical Information of China (English)

    DONG Changjin; ZHAO Bin

    2004-01-01

    Flavonoids from legume root secretion may probably act as signal molecules for expression of Rhizobial "nod" nodulation genes and AM fungal symbiotic gene. Leaf mustard is a non-mycorrhizal plant; it does not contain fiavonoids and other signal molecules. AM fungi could not infect the roots of leaf mustard and form a symbiont in nature,when it was treated with fiavonoids (apigenin or daidzein).The results of trypan blue staining showed that two kinds of AM fungi (G. intraradices and G mosseae) successfully infected the roots of non-mycorrhizal plant leaf mustard. AM fungi grew towards and colonized the roots of leaf mustard,producing young spores and completing the course of life.AM fungi are the only one kind of fungi with ALP activity.The result of ALP staining has also proved that AM fungi infected successfully the roots of leaf mustard. AM fungi (G.intraradices and G. mosseae) that existed in the roots of non-mycorrhizal plant leaf mustard were probed by nested PCR and special molecular probes. The above-mentioned proof chains have fully proved that fiavonoids induced AM fungi (G. intraradices and G mosseae) to infect non-mycorrhizal plant and establish symbiotic relationship.

  7. Arbuscular mycorrhizal wheat inoculation promotes alkane and polycyclic aromatic hydrocarbon biodegradation: Microcosm experiment on aged-contaminated soil.

    Science.gov (United States)

    Ingrid, Lenoir; Lounès-Hadj Sahraoui, Anissa; Frédéric, Laruelle; Yolande, Dalpé; Joël, Fontaine

    2016-06-01

    Very few studies reported the potential of arbuscular mycorrhizal symbiosis to dissipate hydrocarbons in aged polluted soils. The present work aims to study the efficiency of arbuscular mycorrhizal colonized wheat plants in the dissipation of alkanes and polycyclic aromatic hydrocarbons (PAHs). Our results demonstrated that the inoculation of wheat with Rhizophagus irregularis allowed a better dissipation of PAHs and alkanes after 16 weeks of culture by comparison to non-inoculated condition. These dissipations observed in the inoculated soil resulted from several processes: (i) a light adsorption on roots (0.5% for PAHs), (ii) a bioaccumulation in roots (5.7% for PAHs and 6.6% for alkanes), (iii) a transfer in shoots (0.4 for PAHs and 0.5% for alkanes) and mainly a biodegradation. Whereas PAHs and alkanes degradation rates were respectively estimated to 12 and 47% with non-inoculated wheat, their degradation rates reached 18 and 48% with inoculated wheat. The mycorrhizal inoculation induced an increase of Gram-positive and Gram-negative bacteria by 56 and 37% compared to the non-inoculated wheat. Moreover, an increase of peroxidase activity was assessed in mycorrhizal roots. Taken together, our findings suggested that mycorrhization led to a better hydrocarbon biodegradation in the aged-contaminated soil thanks to a stimulation of telluric bacteria and hydrocarbon metabolization in mycorrhizal roots.

  8. [Effects of arbuscular mycorrhizal fungi on root system morphology and sucrose and glucose contents of Poncirus trifoliata].

    Science.gov (United States)

    Zou, Ying-Ning; Wu, Qiang-Sheng; Li, Yan; Huang, Yong-Ming

    2014-04-01

    The effects of inoculation with Glomus mosseae, G. versiforme, and their mixture on plant growth, root system morphology, and sucrose and glucose contents of trifoliate orange (Poncirus trifoliata L.) were studied by pot culture. The results showed that all the inoculated treatments significantly increased the plant height, stem diameter, leaf number, and shoot and root biomass. In addition, the mycorrhizal treatments significantly increased the number of 1st, 2nd, and 3rd lateral roots. Inoculation with arbuscular mycorrhizal fungi significantly increased the root projected area, surface area, volume, and total root length (mainly 0-1 cm root length), but decreased the root average diameter. Meanwhile, G. versiforme showed the best effects. Mycorrhizal inoculation significantly increased the leaf sucrose and root glucose contents, but decreased the leaf glucose and root sucrose contents. Owing to the 'mycorrhizal carbon pool' in roots, inoculation with arbuscular mycorrhizal fungi resulted in high glucose content and low sucrose content of roots, which would facilitate the root growth and development, thereby the establishment of better root system morphology of host plants.

  9. Arbuscular mycorrhizal fungi alter the response of growth and nutrient uptake of snap bean (Phaseolus vulgaris L.) to O3

    Institute of Scientific and Technical Information of China (English)

    Shuguang Wang; Zhaozhong Feng; Xiaoke Wang; Wenliang Gong

    2011-01-01

    The effects of arbuscular mycorrhizal fungi (AMF) Glomus mosseae on the responses to elevated O3 in growth and nutrition of snap bean (Phaseolus vulgaris L. cv Guangzhouyuan) were investigated. Exposure was conducted in growth chambers by using three O3 concentrations (20 (CF), 80 (CFO1) and 120 nL/L (CFO2); 8 hr/day for 75 days). Results showed that elevated O3 slightly impacted overall mycorrhizal colonization, but significantly decreased the proportional frequency of hypha and increased the proportional frequency of spores and vesicles, suggesting that O3 had significant effects on mycorrhizal structure. Elevated O3 significantly decreased yield, dry mass and nutrient contents (N, P, K, Ca and Mg) in both non-mycorrhizal and mycorrhizal plants. However, significant interactive effects were found in most variables due to that the reduction by O3 in the mycorrhizal plants was less than that in the non-mycorrhizal plants. Additionally, AMF increased the concentrations of N, P, Ca, and Mg in shoot and root. It can be concluded that AMF alleviated detrimental effects of increasing O3 on host plant through improving plant nutrition and growth.

  10. [Arbuscular mycorrhizal bioremediation and its mechanisms of organic pollutants-contaminated soils].

    Science.gov (United States)

    Li, Qiuling; Ling, Wanting; Gao, Yanzheng; Li, Fuchun; Xiong, Wei

    2006-11-01

    Arbuscular mycorrhiza (AM), the symbiont of arbuscular mycorrhizal fungi (AMF) and host plant root, has been proved to be able to improve soil structure and enhance the plant resistance to environmental stress. There are more than 170 kinds of AMF worldwide. Recently, the promoted degradation of organic pollutants in soils in the presence of AM was observed, and AM bioremediation (AMB) is becoming a promising and perspective remediation technique for organic pollutants-contaminated soils. This paper reviewed the research progress on the AMB of soils contaminated by typical organic pollutants such as polycyclic aromatic hydrocarbons, PAEs, petroleum, and pesticides. The mechanisms of AMB mainly include the metabolism of organic pollutants by AM fungi, the degradation of these pollutants by the enzymes derived from AM exudation and by the enhanced root exudation and rhizospheric microbial activity in the presence of AM, and the removal of the pollutants by plant uptake and accumulation. As a new approach for the remediation of contaminated soils, some aspects involved in AMB, e.g., the screening of high efficient AM fungi, efficacy of co-existing AM fungi, soil ageing, and plant uptake of organic pollutants from soils in the presence of AM, still need to be further investigated.

  11. Diversity of morphology and function in arbuscular mycorrhizal symbioses in Brachypodium distachyon.

    Science.gov (United States)

    Hong, Jeon J; Park, Yong-Soon; Bravo, Armando; Bhattarai, Kishor K; Daniels, Dierdra A; Harrison, Maria J

    2012-09-01

    Brachypodium distachyon is a grass species that serves as a useful model for wheat and also for many of the grass species proposed as feedstocks for bioenergy production. Here, we monitored B. distachyon symbioses with five different arbuscular mycorrhizal (AM) fungi and identified symbioses that vary functionally with respect to plant performance. Three symbioses promoted significant increases in shoot phosphorus (P) content and shoot growth of Brachypodium, while two associations were neutral. The Brachypodium/Glomus candidum symbiosis showed a classic 'Paris-type' morphology. In the other four AM symbioses, hyphal growth was exclusively intracellular and linear; hyphal coils were not observed and arbuscules were abundant. Expression of the Brachypodium ortholog of the symbiosis-specific phosphate (Pi) transporter MtPT4 did not differ significantly in these five interactions indicating that the lack of apparent functionality did not result from a failure to express this gene or several other AM symbiosis-associated genes. Analysis of the expression patterns of the complete PHT1 Pi transporter gene family and AMT2 gene family in B. distachyon/G. intraradices mycorrhizal roots identified additional family members induced during symbiosis and again, transcript levels were similar in the different Brachypodium AM symbioses. This initial morphological, molecular and functional characterization provides a framework for future studies of functional diversity in AM symbiosis in B. distachyon.

  12. Gold Nanomaterial Uptake from Soil Is Not Increased by Arbuscular Mycorrhizal Colonization of Solanum Lycopersicum (Tomato

    Directory of Open Access Journals (Sweden)

    Jonathan D. Judy

    2016-04-01

    Full Text Available Bioaccumulation of engineered nanomaterials (ENMs by plants has been demonstrated in numerous studies over the past 5–10 years. However, the overwhelming majority of these studies were conducted using hydroponic systems and the degree to which the addition of the biological and chemical components present in the soil might fundamentally alter the potential of plant bioaccumulation of ENMs is unclear. Here, we used two genotypes of Solanum lycopersicum (tomato, reduced mycorrhizal colonization (rmc, a mutant which does not allow arbuscular mycorrhizal fungi (AMF colonization, and its progenitor, 76R, to examine how colonization by AMF alters trends of gold ENM bioaccumulation from a natural soil. Gold was taken up and bioaccumulated by plants of both genotypes. Gold concentrations were significantly higher in the rmc treatment although this was likely attributable to the large differences in biomass between the 76R and rmc plants. Regardless, there was little evidence that AMF played a significant role in trafficking Au ENMs into the plants. Furthermore, despite very low NH4NO3 extractable Au concentrations, Au accumulated at the root-soil interface. Although this observation would seem to suggest that ENMs may have potential to influence this particularly biologically active and important soil compartment, we observed no evidence of this here, as the 76R plants developed a robust AMF symbiosis despite accumulation of Au ENMs at the rhizoplane.

  13. 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.

  14. A unique mitovirus from Glomeromycota, the phylum of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Kitahara, Ryoko; Ikeda, Yoji; Shimura, Hanako; Masuta, Chikara; Ezawa, Tatsuhiro

    2014-08-01

    Arbuscular mycorrhizal (AM) fungi that belong to the phylum Glomeromycota associate with most land plants and supply mineral nutrients to the host plants. One of the four viral segments found by deep-sequencing of dsRNA in the AM fungus Rhizophagus clarus strain RF1 showed similarity to mitoviruses and is characterized in this report. The genome segment is 2,895 nucleotides in length, and the largest ORF was predicted by applying either the mold mitochondrial or the universal genetic code. The ORF encodes a polypeptide of 820 amino acids with a molecular mass of 91.2 kDa and conserves the domain of the mitovirus RdRp superfamily. Accordingly, the dsRNA was designated as R. clarus mitovirus 1 strain RF1 (RcMV1-RF1). Mitoviruses are localized exclusively in mitochondria and thus generally employ the mold mitochondrial genetic code. The distinct codon usage of RcMV1-RF1, however, suggests that the virus is potentially able to replicate not only in mitochondria but also in the cytoplasm. RcMV1-RF1 RdRp showed the highest similarity to the putative RdRp of a mitovirus-like ssRNA found in another AM fungus, followed by RdRp of a mitovirus in an ascomycotan ectomycorrhizal fungus. The three mitoviruses found in the three mycorrhizal fungi formed a deeply branching clade that is distinct from the two major clades in the genus Mitovirus.

  15. Arbuscular mycorrhizal fungi affect glucosinolate and mineral element composition in leaves of Moringa oleifera.

    Science.gov (United States)

    Cosme, Marco; Franken, Philipp; Mewis, Inga; Baldermann, Susanne; Wurst, Susanne

    2014-10-01

    Moringa is a mycorrhizal crop cultivated in the tropics and subtropics and appreciated for its nutritive and health-promoting value. As well as improving plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) can affect plant synthesis of compounds bioactive against chronic diseases in humans. Rhizophagus intraradices and Funneliformis mosseae were used in a full factorial experiment to investigate the impact of AMF on the accumulation of glucosinolates, flavonoids, phenolic acids, carotenoids, and mineral elements in moringa leaves. Levels of glucosinolates were enhanced, flavonoids and phenolic acids were not affected, levels of carotenoids (including provitamin A) were species-specifically reduced, and mineral elements were affected differently, with only Cu and Zn being increased by the AMF. This study presents novel results on AMF effects on glucosinolates in leaves and supports conclusions that the impacts of these fungi on microelement concentrations in edible plants are species dependent. The nonspecific positive effects on glucosinolates and the species-specific negative effects on carotenoids encourage research on other AMF species to achieve general benefits on bioactive compounds in moringa.

  16. Mycorrhizal fungal identity and diversity relaxes plant-plant competition.

    Science.gov (United States)

    Wagg, Cameron; Jansa, Jan; Stadler, Marina; Schmid, Bernhard; van der Heijden, Marcel G A

    2011-06-01

    There is a great interest in ecology in understanding the role of soil microbial diversity for plant productivity and coexistence. Recent research has shown increases in species richness of mutualistic soil fungi, the arbuscular mycorrhizal fungi (AMF), to be related to increases in aboveground productivity of plant communities. However, the impact of AMF richness on plant-plant interactions has not been determined. Moreover, it is unknown whether species-rich AMF communities can act as insurance to maintain productivity in a fluctuating environment (e.g., upon changing soil conditions). We tested the impact of four different AMF taxa and of AMF diversity (no AMF, single AMF taxa, and all four together) on competitive interactions between the legume Trifolium pratense and the grass Lolium multiflorum grown under two different soil conditions of low and high sand content. We hypothesized that more diverse mutualistic interactions (e.g., when four AMF taxa are present) can ease competitive effects between plants, increase plant growth, and maintain plant productivity across different soil environments. We used quantitative PCR to verify that AMF taxa inoculated at the beginning of the experiment were still present at the end. The presence of AMF reduced the competitive inequality between the two plant species by reducing the growth suppression of the legume by the grass. High AMF richness enhanced the combined biomass production of the two plant species and the yield of the legume, particularly in the more productive soil with low sand content. In the less productive (high sand content) soil, the single most effective AMF had an equally beneficial effect on plant productivity as the mixture of four AMF. Since contributions of single AMF to plant productivity varied between both soils, higher AMF richness would be required to maintain plant productivity in heterogeneous environments. Overall this work shows that AMF diversity promotes plant productivity and that AMF

  17. [Effect of Ryegrass and Arbuscular Mycorrhizal on Cd Absorption by Varieties of Tomatoes and Cadmium Forms in Soil].

    Science.gov (United States)

    Chen, Yong-qin; Jiang, Ling; Xu, Wei-hong; Chi, Sun-lin; Chen, Xu-gen; Xie, Wen-wen; Xiong, Shi- juan; Zhang, Jin-zhong; Xiong, Zhi-ting

    2015-12-01

    Field trial was carried out to investigate the effects of ryegrass and arbuscular mycorrhizal single or compound treatment to two varieties of tomato ("Defu mm-8" and "Luobeiqi") on the plant growth, concentrations and accumulations of Cd as well as the impact on microorganisms, enzyme activities, pH and Cd forms in soil when exposed to Cd (5.943 mg · kg⁻¹). The results showed that dry weights of fruit, root, stem, leaf and plant significantly increased by single or compound treatment of ryegrass and arbuscular mycorrhizal by 14.1%-38.4% and 4.2%-18.3%, 20.9%-31.5% and 8.4%-10.3%, 13.0%-16.8% and 3.0%-9.5%, 10.7%- 16.8% and 2.7%-7.6%, 14.3%-36.6% and 4.5%-16.8%, respectively. The amounts of bacteria, fungi, actinomycetes of soil and the activities of urease, invertase, acid phosphatase, catalase in soil were increased by single or compound treatment of ryegrass and arbuscular mycorrhizal, and the soil microorganism amounts and enzyme activities significantly differed between the two varieties of tomato and treatments (P Cd, CAB-Cd, Fe-Mn-Cd and total Cd in soil were decreased, and the total Cd content was decreased by 16.9%-27.8%. Cadmium concentrations in fruit, leaf, stem and root of both varieties were significantly decreased by 6.9%-40.9%, 5.7%-40.1%, 4.6%-34.7% and 9.8%-42.4%, respectively. Cadmium accumulations in tomato were in order of leaf > stem > root > fruit. Comparing the two tomato varieties, Cd concentrations and Cd accumulations in fruit and plant were in order of "Luobeiqi" < "Defu mm-8" in the presence or absence of single or compound treatment of ryegrass and arbuscular mycorrhizal.

  18. Influence of arbuscular mycorrhizal fungi and the expression of K+/Cs+ transporters on the accumulation of caesium by plants

    OpenAIRE

    Wiesel, Lea

    2011-01-01

    Radiocaesium (134Cs, 137Cs) is of environmental concern because of its incorporation into the food chain and prolonged emission of harmful radiation. Plants take up caesium via cation transporters which cannot discriminate between radioactive and stable caesium (133Cs). Around 80% of angiosperms live in symbiosis with arbuscular mycorrhizal (AM) fungi that deliver mineral nutrients to their hosts. Contrasting effects of AM fungi on caesium accumulation by plants have been reported. The ultima...

  19. Changes in the Diversity of Soil Arbuscular Mycorrhizal Fungi after Cultivation for Biofuel Production in a Guantanamo (Cuba) Tropical System

    OpenAIRE

    2012-01-01

    The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soi...

  20. Growth, Cadmium Accumulation and Physiology of Marigold (Tagetes erecta L.) as Affected by Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    LIU Ling-Zhi; GONG Zong-Qiang; ZHANG Yu-Long; LI Pei-Jun

    2011-01-01

    A pot experiment was carried out to study the effects of three arbuscular mycorrhizal fungi (AMF), including Glomus intraradices, Glomus constrictum and Glomus mosseae, on the growth, root colonization and Cd accumulation of marigold (Tagetes erecta L.) at Cd addition levels of 0, 5 and 50 mg kg-1 in soil. The physiological characteristics, such as chlorophyll content, soluble sugar content, soluble protein content and antioxidant enzyme activity, of Tagetes erecta L. were also investigated. The symbiotic relationship between the marigold plant and arbuscular mycorrhizal fungi was well established under Cd stress. The symbiotic relationship was reflected by the better physiobiochemical parameters of the marigold plants inoculated with the three AMF isolates where the colonization rates in the roots were between 34.3% and 88.8%. Compared with the non-inoculated marigold plants, the shoot and root biomass of the inoculated marigold plants increased by 15.2%-47.5% and 47.8%-130.1%, respectively, and the Cd concentration and accumulation decreased. The chlorophyll and soluble sugar contents in the mycorrhizal marigold plants increased with Cd addition, indicating that AMF inoculation helped the marigold plants to grow by resisting Cd stress. The antioxidant enzymes reacted differently with the three AMF under Cd stress. For plants inoculated with G. constrictum and G. mosseae, the activities of superoxide dismutase (SOD) and catalase (CAT) increased with increasing Cd addition, but peroxidase (POD) activity decreased with increasing Cd addition. For plants inoculated with G. intruradices, three of the antioxidant enzyme activities were significantly decreased at high levels of Cd addition. Overall, the activities of the three antioxidant enzymes in the plants inoculated with AMF were higher than those of the plants without AMF inoculation under Cd stress. Our results support the view that antioxidant enzymes have a great influence on the biomass of plants

  1. Influence of Arbuscular Mycorrhizal Fungi on Growth, Mineral Nutrition and Chlorogenic Acid Content of Lonicera confusa Seedlings Under Field Conditions

    Institute of Scientific and Technical Information of China (English)

    SHI An-Dong; LI Qian; HUANG Jian-Guo; YUAN Ling

    2013-01-01

    Lonicera confusa,a traditional Chinese medicine herb for treating cold,flu,acute fever,and so forth,is often grown artificially in acidic soils and suffers from phosphorus (P) deficiency.A five-year field experiment was carried out to study the colonization rate,growth,nutrition,and chlorogenic acid content of Lonicera confusa seedlings inoculated with arbuscular mycorrhizal (AM) fungi,Glomus etunicatum and Glomus intraradices.Before transplanting into a field,both AM-inoculated and uninoculated control plants were cultured in nursery beds.In the plants inoculated with the AM fungi,the colonization rate decreased linearly with time and a greater decrease was observed in the plants inoculated with G.intraradices than with G.etunicatum,while the AM colonization increased from 0% to 12.1% in the uninoculated control plants 5 years after transplanting.Plant height,crown diameter,number of new branches,and flower yield increased significantly by AM inoculation as compared to the uninoculated control.Phosphorus concentrations in leaves and flowers increased,and plant uptake of nutrients,e.g.,nitrogen (N),P,and potassium (K),was also enhanced significantly by AM inoculation.The Lonicera confusa seedlings had a better response to inoculation of G.intraradices than G.etunicatum in both growth and chlorogenic acid content in flowers.In contrast,both plant P uptake and P concentrations in leaves and flowers were similar between two fungal inoculations.The positive responses of Lonicera confusa to AM inoculation in growth,nutrient uptake,flowering,and chlorogenic acid content in flowers suggested that AM inoculation in nursery beds could promote the plant growth and increase chlorogenic acid content in flowers of Lonicera confusa when grown on acidic and P-deficient soils.

  2. Roles of Arbuscular Mycorrhizal Fungi and Soil Abiotic Conditions in the Establishment of a Dry Grassland Community.

    Directory of Open Access Journals (Sweden)

    Jana Knappová

    Full Text Available The importance of soil biota in the composition of mature plant communities is commonly acknowledged. In contrast, the role of soil biota in the early establishment of new plant communities and their relative importance for soil abiotic conditions are still poorly understood.The aim of this study was to understand the effects of soil origin and soil fungal communities on the composition of a newly established dry grassland plant community. We used soil from two different origins (dry grassland and abandoned field with different pH and nutrient and mineral content. Grassland microcosms were established by sowing seeds of 54 species of dry grassland plants into the studied soils. To suppress soil fungi, half of the pots were regularly treated with fungicide. In this way, we studied the independent and combined effects of soil origin and soil community on the establishment of dry grassland communities.The effect of suppressing the soil fungal community on the richness and composition of the plant communities was much stronger than the effect of soil origin. Contrary to our expectations, the effects of these two factors were largely additive, indicating the same degree of importance of soil fungal communities in the establishment of species-rich plant communities in the soils from both origins. The negative effect of suppressing soil fungi on species richness, however, occurred later in the soil from the abandoned field than in the soil from the grassland. This result likely occurred because the negative effects of the suppression of fungi in the field soil were caused mainly by changes in plant community composition and increased competition. In contrast, in the grassland soil, the absence of soil fungi was limiting for plants already at the early stages of their establishment, i.e., in the phases of germination and early recruitment. While fungicide affects not only arbuscular mycorrhizal fungi but also other biota, our data indicate that changes

  3. Mating type gene homologues and putative sex pheromone-sensing pathway in arbuscular mycorrhizal fungi, a presumably asexual plant root symbiont.

    Science.gov (United States)

    Halary, Sébastien; Daubois, Laurence; Terrat, Yves; Ellenberger, Sabrina; Wöstemeyer, Johannes; Hijri, Mohamed

    2013-01-01

    The fungal kingdom displays a fascinating diversity of sex-determination systems. Recent advances in genomics provide insights into the molecular mechanisms of sex, mating type determination, and evolution of sexual reproduction in many fungal species in both ancient and modern phylogenetic lineages. All major fungal groups have evolved sexual differentiation and recombination pathways. However, sexuality is unknown in arbuscular mycorrhizal fungi (AMF) of the phylum Glomeromycota, an ecologically vital group of obligate plant root symbionts. AMF are commonly considered an ancient asexual lineage dating back to the Ordovician, approximately 460 M years ago. In this study, we used genomic and transcriptomic surveys of several AMF species to demonstrate the presence of conserved putative sex pheromone-sensing mitogen-activated protein (MAP) kinases, comparable to those described in Ascomycota and Basidiomycota. We also find genes for high mobility group (HMG) transcription factors, homologous to SexM and SexP genes in the Mucorales. The SexM genes show a remarkable sequence diversity among multiple copies in the genome, while only a single SexP sequence was detected in some isolates of Rhizophagus irregularis. In the Mucorales and Microsporidia, the sexM gene is flanked by genes for a triosephosphate transporter (TPT) and a RNA helicase, but we find no evidence for synteny in the vicinity of the Sex locus in AMF. Nonetheless, our results, together with previous observations on meiotic machinery, suggest that AMF could undergo a complete sexual reproduction cycle.

  4. Mating type gene homologues and putative sex pheromone-sensing pathway in arbuscular mycorrhizal fungi, a presumably asexual plant root symbiont.

    Directory of Open Access Journals (Sweden)

    Sébastien Halary

    Full Text Available The fungal kingdom displays a fascinating diversity of sex-determination systems. Recent advances in genomics provide insights into the molecular mechanisms of sex, mating type determination, and evolution of sexual reproduction in many fungal species in both ancient and modern phylogenetic lineages. All major fungal groups have evolved sexual differentiation and recombination pathways. However, sexuality is unknown in arbuscular mycorrhizal fungi (AMF of the phylum Glomeromycota, an ecologically vital group of obligate plant root symbionts. AMF are commonly considered an ancient asexual lineage dating back to the Ordovician, approximately 460 M years ago. In this study, we used genomic and transcriptomic surveys of several AMF species to demonstrate the presence of conserved putative sex pheromone-sensing mitogen-activated protein (MAP kinases, comparable to those described in Ascomycota and Basidiomycota. We also find genes for high mobility group (HMG transcription factors, homologous to SexM and SexP genes in the Mucorales. The SexM genes show a remarkable sequence diversity among multiple copies in the genome, while only a single SexP sequence was detected in some isolates of Rhizophagus irregularis. In the Mucorales and Microsporidia, the sexM gene is flanked by genes for a triosephosphate transporter (TPT and a RNA helicase, but we find no evidence for synteny in the vicinity of the Sex locus in AMF. Nonetheless, our results, together with previous observations on meiotic machinery, suggest that AMF could undergo a complete sexual reproduction cycle.

  5. Influence of arbuscular mycorrhizal fungi and copper on growth, accumulation of osmolyte, mineral nutrition and antioxidant enzyme activity of pepper (Capsicum annuum L.).

    Science.gov (United States)

    Abdel Latef, Arafat Abdel Hamed

    2011-08-01

    The effect of arbuscular mycorrhizal (AM) fungi inoculation on pepper (Capsicum annuum L. cv. Zhongjiao 105) plant growth and on some physiological parameters in response to increasing soil Cu concentrations was studied. Treatments consisted of inoculation or not with Glomus mosseae and the addition of Cu to soil at the concentrations of 0 (control), 2 (low), 4 (medium), and 8 (high) mM CuSO(4). AM fungal inoculation decreased Cu concentrations in plant organs and promoted biomass yields as well as the contents of chlorophyll, soluble sugar, total protein, and the concentrations of P, K, Ca, and Mg. Plants grown in high Cu concentration exhibited a Cu-induced proline accumulation and also an increase in total free amino acid contents; however, both were lower in mycorrhizal pepper. Cu-induced oxidative stress by increasing lipid peroxidation rates and the activity of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, and AM symbiosis enhanced these antioxidant enzyme activities and decreased oxidative damage to lipids. In conclusion G. mosseae was able to maintain an efficient symbiosis with pepper plants in contaminated Cu soils, improving plant growth under these conditions, which is likely to be due to reduced Cu accumulation in plant tissues, reduced oxidative stress and damage to lipids, or enhanced antioxidant capacity.

  6. Soil fungal and bacterial biomass determined by epifluorescence microscopy and mycorrhizal spore density in different sugarcane managements

    Directory of Open Access Journals (Sweden)

    Adriana Pereira Aleixo

    2014-04-01

    Full Text Available Crop productivity and sustainability have often been related to soil organic matter and soil microbial biomass, especially because of their role in soil nutrient cycling. This study aimed at measuring fungal and bacterial biomass by epifluorescence microscopy and arbuscular mycorrhizal fungal (AMF spore density in sugarcane (Saccharum officinarum L. fields under different managements. We collected soil samples of sugarcane fields managed with or without burning, with or without mechanized harvest, with or without application of vinasse and from nearby riparian native forest. The soil samples were collected at 10cm depth and storage at 4°C until analysis. Fungal biomass varied from 25 to 37µg C g-1 dry soil and bacterial from 178 to 263µg C g-1 dry soil. The average fungal/bacterial ratio of fields was 0.14. The AMF spore density varied from 9 to 13 spores g-1 dry soil. The different sugarcane managements did not affect AMF spore density. In general, there were no significant changes of microbial biomass with crop management and riparian forest. However, the sum of fungal and bacterial biomass measured by epifluorescence microscopy (i.e. 208-301µg C g-1 dry soil was very close to values of total soil microbial biomass observed in other studies with traditional techniques (e.g. fumigation-extraction. Therefore, determination of fungal/bacterial ratios by epifluorescence microscopy, associated with other parameters, appears to be a promising methodology to understand microbial functionality and nutrient cycling under different soil and crop managements.

  7. The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato.

    Science.gov (United States)

    Hage-Ahmed, Karin; Krammer, Johannes; Steinkellner, Siegrid

    2013-10-01

    Arbuscular mycorrhizal fungi (AMF) and their bioprotective aspects are of great interest in the context of sustainable agriculture. Combining the benefits of AMF with the utilisation of plant species diversity shows great promise for the management of plant diseases in environmentally compatible agriculture. In the present study, AMF were tested against Fusarium oxysporum f. sp. lycopersici with tomato intercropped with either leek, cucumber, basil, fennel or tomato itself. Arbuscular mycorrhizal (AM) root colonisation of tomato was clearly affected by its intercropping partners. Tomato intercropped with leek showed even a 20 % higher AM colonisation rate than tomato intercropped with tomato. Positive effects of AMF expressed as an increase of tomato biomass compared to the untreated control treatment could be observed in root as well as in shoot weights. A compensation of negative effects of F. oxysporum f. sp. lycopersici on tomato biomass by AMF was observed in the tomato/leek combination. The intercropping partners leek, cucumber, basil and tomato had no effect on F. oxysporum f. sp. lycopersici disease incidence or disease severity indicating no allelopathic suppression; however, tomato co-cultivated with tomato clearly showed a negative effect on one plant/pot with regard to biomass and disease severity of F. oxysporum f. sp. lycopersici. Nonetheless, bioprotective effects of AMF resulting in the decrease of F. oxysporum f. sp. lycopersici disease severity were evident in treatments with AMF and F. oxysporum f. sp. lycopersici co-inoculation. However, these bioprotective effects depended on the intercropping partner since these effects were only observed in the tomato/leek and tomato/basil combination and for the better developed plant of tomato/tomato. In conclusion, the effects of the intercropping partner on AMF colonisation of tomato are of great interest for crop plant communities and for the influences on each other. The outcome of the bioprotective

  8. Red list plants: colonization by arbuscular mycorrhizal fungi and dark septate endophytes.

    Science.gov (United States)

    Fuchs, B; Haselwandter, K

    2004-08-01

    Since information concerning the mycorrhization of endangered plants is of major importance for their potential re-establishment, we determined the mycorrhizal status of Serratula tinctoria (Asteraceae), Betonica officinalis (Lamiaceae), Drosera intermedia (Droseraceae) and Lycopodiella inundata (Lycopodiaceae), occurring at one of two wetland sites (fen meadow and peat bog), which differed in soil pH and available P levels. Root colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) was quantified. Colonization by AMF appeared to be more frequent in the fen meadow than in the peat bog, and depended on the host plant. Roots of S. tinctoria and B. officinalis were well colonized by AMF in the fen meadow (35-55% root length) and both arbuscules and vesicles were observed to occur in spring as well as in autumn. In the peat bog, L. inundata showed a low level of root colonization in spring, when vesicles were found frequently but no arbuscules. In roots of D. intermedia from the peat bog, arbuscules and vesicles were observed, but AMF colonization was lower than in L. inundata. In contrast, the amount of AMF spores extracted from soil at the peat bog site was higher than from the fen meadow soil. Spore numbers did not differ between spring and autumn in the fen meadow, but they were higher in spring than in autumn in the peat bog. Acaulospora laevis or A. colossica and Glomus etunicatum were identified amongst the AMF spores extracted from soil at the two sites. S. tinctoria and B. officinalis roots were also regularly colonized by DSE (18-40% root length), while L. inundata was only rarely colonized and D. intermedia did not seem to be colonized by DSE at all.

  9. Arbuscular mycorrhizal fungi facilitate the invasion of Solidago canadensis L. in southeastern China

    Science.gov (United States)

    Yang, Ruyi; Zhou, Gang; Zan, Shuting; Guo, Fuyu; Su, Nannan; Li, Jing

    2014-11-01

    The significance of arbuscular mycorrhizal fungi (AMF) in the process of plant invasion is still poorly understood. We hypothesize that invasive plants would change local AMF community structure in a way that would benefit themselves but confer less advantages to native plants, thus influencing the extent of plant interactions. An AMF spore community composed of five morphospecies of Glomus with equal density (initial AMF spore community, I-AMF) was constructed to test this hypothesis. The results showed that the invasive species, Solidago canadensis, significantly increased the relative abundance of G. geosperum and G. etunicatum (altered AMF spore community, A-AMF) compared to G. mosseae, which was a dominant morphospecies in the monoculture of native Kummerowia striata. The shift in AMF spore community composition driven by S. canadensis generated functional variation between I-AMF and A-AMF communities. For example, I-AMF increased biomass and nutrient uptake of K. striata in both monocultures and mixtures of K. striata and S. canadensis compared to A-AMF. In contrast, A-AMF significantly enhanced root nitrogen (N) acquisition of S. canadensis grown in mixture. Moreover, mycorrhizal-mediated 15N uptake provided direct evidence that I-AMF and A-AMF differed in their affinities with native and invading species. The non-significant effect of A-AMF on K. striata did not result from allelopathy as root exudates of S. canadensis exhibited positive effects on seed germination and biomass of K. striata under naturally occurring concentrations. When considered together, we found that A-AMF facilitated the invasion of S. canadensis through decreasing competitiveness of the native plant K. striata. The results supported our hypothesis and can be used to improve our understanding of an ecosystem-based perspective towards exotic plant invasion.

  10. Arbuscular mycorrhizal symbiosis influences arsenic accumulation and speciation in Medicago truncatula L. in arsenic-contaminated soil.

    Science.gov (United States)

    Zhang, Xin; Ren, Bai-Hui; Wu, Song-Lin; Sun, Yu-Qing; Lin, Ge; Chen, Bao-Dong

    2015-01-01

    In two pot experiments, wild type and a non-mycorrhizal mutant (TR25:3-1) of Medicago truncatula were grown in arsenic (As)-contaminated soil to investigate the influences of arbuscular mycorrhizal fungi (AMF) on As accumulation and speciation in host plants. The results indicated that the plant biomass of M. truncatula was dramatically increased by AM symbiosis. Mycorrhizal colonization significantly increased phosphorus concentrations and decreased As concentrations in plants. Moreover, mycorrhizal colonization generally increased the percentage of arsenite in total As both in shoots and roots, while dimethylarsenic acid (DMA) was only detected in shoots of mycorrhizal plants. The results suggested that AMF are most likely to get involved in the methylating of inorganic As into less toxic organic DMA and also in the reduction of arsenate to arsenite. The study allowed a deeper insight into the As detoxification mechanisms in AM associations. By using the mutant M. truncatula, we demonstrated the importance of AMF in plant As tolerance under natural conditions.

  11. Symbiotic interactions between arbuscular mycorrhizal (AM) fungi and male papaya plants: its status, role and implications.

    Science.gov (United States)

    Khade, Sharda W; Rodrigues, Bernard F; Sharma, Prabhat K

    2010-01-01

    Experiments were conducted to study the arbuscular mycorrhizal (AM) status and its role in P-uptake through assay of root phosphatases activities in four varieties of male Carica papaya L. viz. CO-1, CO-2, Honey Dew and Washington during flowering stages. In the present study, mean total root colonization of AM fungi recorded peak increase in flowering stage-II while mean root phosphatase (acid and alkaline) activities recorded peak increase in flowering stage-I. Unlike root colonization and root phosphatase activities, spore density did not exhibit any definite patterns and recorded a narrow range of fluctuation during different flowering stages of male C. papaya. The study brought out the fact that root colonization and spore density of AM fungi along with root phosphatase activities varied significantly within the four varieties of male C. papaya plants during each flowering stage. The study also recorded consistently higher acid root phosphatase activity than alkaline root phosphatase activity under P-deficient, acidic soil conditions during all flowering stages of male C. papaya plants. Studies revealed that the root colonization of AM fungi influenced root phosphatase activities (acid and alkaline) positively and significantly during all flowering stages of male C. papaya plants. A total of twelve species of AM fungi belonging to five genera viz. Acaulospora, Dentiscutata, Gigaspora, Glomus, and Racocetra were recovered from the rhizosphere of male C. papaya plants.

  12. Influence of Arbuscular Mycorrhizal Fungus (AMF) on degradation of iron-cyanide complexes

    Science.gov (United States)

    Sut, Magdalena; Boldt-Burisch, Katja; Raab, Thomas

    2015-04-01

    Soil contamination in the vicinities of former Manufactured Gas Plant (MGP) sites is a worldwide known environmental issue. The pollutants, in form of iron-cyanide complexes, originating from the gas purification process, create a risk for human health due to potential release of toxic free cyanide, CN(aq) and HCN(g), (aq).The management and remediation of cyanide contaminated soil can be very challenging due to the complex chemistry and toxicity of CN compounds. The employment of phytoremediation to remove or stabilize contaminants at a former MGP site is an inexpensive process, but can be limited through shallow rotting, decreased biomass, poor growing and the risk of secondary accumulation. However, this adaptation may be enhanced via arbuscular mycorrhizal fungi (AMF) activity, which may cooperate on the degradation, transformation or uptake of the contaminants. We would like to present our preliminary results from the ongoing project concerning toxic substrate-AMF-plant relation, based on studying the site of a former MGP site. In situ experiments contributed to identifying those fungi that are likely to persist in extremely acidic and toxic conditions. Subsequently, commercially available Rhizophagus irregularis was grown in sterilized, un-spiked soil with the roots of the host plant Calamagrostis epigejos. Extracted roots and AMF hyphae were used in the batch experiment, were the potential of this association on degradation of iron-cyanide complexes, in form of potassium ferrocyanide solution, was assessed.

  13. Kinetic Study on Flooded Soil Recovery Using Soil Containing Arbuscular Mycorrhizal Fungi

    Directory of Open Access Journals (Sweden)

    Zainol N.

    2016-01-01

    Full Text Available The purpose of this research was to determine the kinetic parameters for flooded soil recovery via soil containing Arbuscular Mycorrhizal fungi (AMF. The general procedures of this experiment started by preparation of simulated flooded soil (FS and soil containing AMF (SA. Mixed soil was prepared by mixing FS and SA with ratio 1:1. Onion plant was chosen as a host plant and planted in the mixed soil for 14 days. The plantation was conducted in ambient temperature. The nutrients (nitrogen, phosphorus and potassium concentrations in the soil were tested using HACH Spectrophotomer. The Michaelis-Menten equation was used to study the nutrients recovery in soil. The Lineweaver-Bulk plot was used to solve the Michaelis-Menten equation. From the experiment conducted, the maximum nutrient uptake (Vmax and bonding affinity (Km obtained for nitrogen (N were 6.28mg/l.d and 82.17 mg/l, for phosphorus (P were 9.80 mg/l.d and 60.96 mg/l.d and for potassium (K were 0.07mg/l.d and 4.55mg/l. By comparing the result with other researcher, it showed that the Vmax and Km of nitrogen (N and phosphorus (P obtained were higher than other research. This was because the onion required a high level of N and P in the soil compared to other host plant.

  14. Rhizobacteria Selection to Enhance Spore Germination and Hyphal Length of Arbuscular Mycorrhizal Fungi in Vitro

    Directory of Open Access Journals (Sweden)

    Cecep Hidayat

    2013-04-01

    Full Text Available In natural condition, Arbuscular Mycorrhizal Fungi (AMF are surrounded by bacteria that help fungi symbiosis. The research aimed to get rhizobacteria that can act as Mycorrhiza Helper Bacteria (MHB had been held at Soil Biology and Biotechnology Laboratory Faculty of Agriculture Unpad from February to March 2012. The experimental design used was completely randomized design with 11 treatments (bo= without rhizobacteria, b1= Pseudomonas diminuta, b2 = Bacillus alvei, b3 = B. mycoides, b4 = P. malei, b5= P. diminuta + B. alvei, b6 = P. diminuta + B. mycoides, b7 = P. diminuta + P. malei, b8 = B. alvei + B. mycoides, b9 = B. alvei + P. malei, b10= B. mycoides + P. malei with 3 replications. Parameters evaluated were spore germination percentage and hyphal length of Glomus sp at 7, 14, 21, and 28 day after planting. The result showed that P. diminuta enhanced spore germination percentage and hyphal length of Glomus spas much as 224 % and 330%respectively than control. So, P. diminuta can be used as MHB.

  15. Initial development and chemical components of sugarcane under water stress associated with arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Carmem C. M. de Sousa

    2015-06-01

    Full Text Available ABSTRACT The objective of this study was to evaluate the effects of water stress levels in the soil and a mix (or: a mixed inoculum of four species: Claroideoglomus etunicatum, Gigasporas rosea, Acaulospora longula, Fuscutata heterogama of arbuscular mycorrhizal fungi (AMF on initial vegetative growth, fresh and dry biomass production, root colonization, phosphorus, proteins, enzymes and amino acid of the sugarcane variety RB 857515 under greenhouse conditions. The experiment was set in a randomized block design in a 2 x 2 factorial scheme with four treatments (T1 - 50% PC - pot capacity, with AMF; T2 - 100% PC with AMF; T3 - 50% PC without AMF; T4 - 100% PC without AMF with 16 replicates. The water stress level of 50% PC decreased stem diameter and shoot and root fresh weight of sugarcane plants, as well as AMF in the soil and in plant roots. However, AMF and the water stress level of 50% PC, separately or combined, did not affect plant height, number of leaves, dry matter and contents of phosphorus, total soluble proteins, catalase, ascorbate peroxidase, polyphenoloxidase, peroxidase and proline of the sugarcane variety RB857515.

  16. Arbuscular mycorrhizal fungi communities from tropical Africa reveal strong ecological structure.

    Science.gov (United States)

    Rodríguez-Echeverría, Susana; Teixeira, Helena; Correia, Marta; Timóteo, Sérgio; Heleno, Ruben; Öpik, Maarja; Moora, Mari

    2017-01-01

    Understanding the distribution and diversity of arbuscular mycorrhizal fungi (AMF) and the rules that govern AMF assemblages has been hampered by a lack of data from natural ecosystems. In addition, the current knowledge on AMF diversity is biased towards temperate ecosystems, whereas little is known about other habitats such as dry tropical ecosystems. We explored the diversity and structure of AMF communities in grasslands, savannas, dry forests and miombo in a protected area under dry tropical climate (Gorongosa National Park, Mozambique) using 454 pyrosequencing. In total, 147 AMF virtual taxa (VT) were detected, including 22 VT new to science. We found a high turnover of AMF with ˂ 12% of VT present in all vegetation types. Forested areas supported more diverse AMF communities than savannas and grassland. Miombo woodlands had the highest AMF richness, number of novel VT, and number of exclusive and indicator taxa. Our data reveal a sharp differentiation of AMF communities between forested areas and periodically flooded savannas and grasslands. This marked ecological structure of AMF communities provides the first comprehensive landscape-scale evidence that, at the background of globally low endemism of AMF, local communities are shaped by regional processes including environmental filtering by edaphic properties and natural disturbance.

  17. A plausible mechanism of biosorption in dual symbioses by vesicular-arbuscular mycorrhizal in plants.

    Science.gov (United States)

    Azmat, Rafia; Hamid, Neelofer

    2015-03-01

    Dual symbioses of vesicular-arbuscular mycorrhizal (VAM) fungi with growth of Momordica charantia were elucidated in terms of plausible mechanism of biosorption in this article. The experiment was conducted in green house and mixed inoculum of the VAM fungi was used in the three replicates. Results demonstrated that the starch contents were the main source of C for the VAM to builds their hyphae. The increased plant height and leaves surface area were explained in relation with an increase in the photosynthetic rates to produce rapid sugar contents for the survival of plants. A decreased in protein, and amino acid contents and increased proline and protease activity in VAM plants suggested that these contents were the main bio-indicators of the plants under biotic stress. The decline in protein may be due to the degradation of these contents, which later on converted into dextrose where it can easily be absorbed by for the period of symbioses. A mechanism of C chemisorption in relation with physiology and morphology of plant was discussed.

  18. Reforestation of bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    N. Krishnakumar

    2012-11-01

    Full Text Available Open cast mining for bauxite at Yercaud hills (India resulted indegradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils. To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM fungi essential for plant growth.However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum(Thatcher Gerd. & Trappe emend. Walker & Koske, G. geosporum(Nicol. & Gerd. Walker were isolated, cultured and inoculated into the seedlings of Eucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings of E. tereticornis showed 95% survival over the control seedlings and their growth was also significantlyhigher. Tissue nutrients (N, P, K were also found higher inAM fungi inoculated E. tereticornis than un inoculated control seedlings.

  19. Upscaling Arbuscular Mycorrhizal Symbiosis and Related Agroecosystems Services in Smallholder Farming Systems

    Directory of Open Access Journals (Sweden)

    Marjorie Bonareri Oruru

    2016-01-01

    Full Text Available Smallholder farming systems form unique ecosystems that can protect beneficial soil biota and form an important source of useful genetic resources. They are characterized by high level of agricultural diversity mainly focused on meeting farmers’ needs. Unfortunately, these systems often experience poor crop production mainly associated with poor planning and resource scarcity. Soil fertility is among the primary challenges faced by smallholder farmers, which necessitate the need to come up with affordable and innovative ways of replenishing soils. One such way is the use of microbial symbionts such as arbuscular mycorrhizal fungi (AMF, a beneficial group of soil microbiota that form symbiotic associations with majority of cultivated crops and play a vital role in biological soil fertility, plant nutrition, and protection. AMF can be incorporated in smallholder farming systems to help better exploit chemical fertilizers inputs which are often unaffordable to many smallholder farmers. The present review highlights smallholder farming practices that could be innovatively redesigned to increase AMF symbiosis and related agroecosystem services. Indeed, the future of global food security depends on the success of smallholder farming systems, whose crop productivity depends on the services provided by well-functioning ecosystems, including soil fertility.

  20. Arbuscular mycorrhizal associations and occurrence of dark septate endophytes in the roots of Brazilian weed plants.

    Science.gov (United States)

    Massenssini, André Marcos; Bonduki, Víctor Hugo Araújo; Tótola, Marcos Rogério; Ferreira, Francisco Affonso; Costa, Maurício Dutra

    2014-02-01

    The ecology of weed plants includes their interactions with soil microorganisms, such as mutualistic partners that may contribute to their adaptation and competitive success in the agricultural fields. Despite the importance of microorganisms to plant growth, knowledge on weed-symbiont associations is still incipient compared to crops. Thus, a survey for the presence of arbuscular mycorrhiza (AM) and dark septate endophyte (DSE) associations in the roots of 50 weed species was done in three distinct areas during the dry and rainy seasons. We found that 41 and 29 out of the 50 species were associated with AM fungi and DSE, respectively, and 27 species presented both associations. All the plant species not forming AM belong to families thought to be nonmycorrhizal, such as Amaranthaceae, Commelinaceae, Brassicaceae, and Cyperaceae. The most common morphotype of AM observed was the Arum-type. No significant differences were found in root length colonization between the areas or seasons. For 19 species surveyed, this is the first report on their mycorrhizal status.

  1. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato.

    Science.gov (United States)

    Ruiz-Lozano, Juan Manuel; Aroca, Ricardo; Zamarreño, Ángel María; Molina, Sonia; Andreo-Jiménez, Beatriz; Porcel, Rosa; García-Mina, José María; Ruyter-Spira, Carolien; López-Ráez, Juan Antonio

    2016-02-01

    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 drought on lettuce and tomato plant performance and hormone levels were investigated in non-AM and AM plants. Three different water regimes were applied, and their effects were analysed over time. AM plants showed an improved growth rate and efficiency of photosystem II than non-AM plants under drought from very early stages of plant colonization. The levels of the phytohormone abscisic acid, as well as the expression of the corresponding marker genes, were influenced by drought stress in non-AM and AM plants. The levels of strigolactones and the expression of corresponding marker genes were affected by both AM symbiosis and drought. The results suggest that AM symbiosis alleviates drought stress by altering the hormonal profiles and affecting plant physiology in the host plant. In addition, a correlation between AM root colonization, strigolactone levels and drought severity is shown, suggesting that under these unfavourable conditions, plants might increase strigolactone production in order to promote symbiosis establishment to cope with the stress.

  2. Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd. Poir from Brazilian semi-arid

    Directory of Open Access Journals (Sweden)

    Tancredo Augusto Feitosa de Souza

    2016-06-01

    Full Text Available Abstract Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites.

  3. Transition Metal Transport in Plants and Associated Endosymbionts: Arbuscular Mycorrhizal Fungi and Rhizobia.

    Science.gov (United States)

    González-Guerrero, Manuel; Escudero, Viviana; Saéz, Ángela; Tejada-Jiménez, Manuel

    2016-01-01

    Transition metals such as iron, copper, zinc, or molybdenum are essential nutrients for plants. These elements are involved in almost every biological process, including photosynthesis, tolerance to biotic and abiotic stress, or symbiotic nitrogen fixation. However, plants often grow in soils with limiting metallic oligonutrient bioavailability. Consequently, to ensure the proper metal levels, plants have developed a complex metal uptake and distribution system, that not only involves the plant itself, but also its associated microorganisms. These microorganisms can simply increase metal solubility in soils and making them more accessible to the host plant, as well as induce the plant metal deficiency response, or directly deliver transition elements to cortical cells. Other, instead of providing metals, can act as metal sinks, such as endosymbiotic rhizobia in legume nodules that requires relatively large amounts to carry out nitrogen fixation. In this review, we propose to do an overview of metal transport mechanisms in the plant-microbe system, emphasizing the role of arbuscular mycorrhizal fungi and endosymbiotic rhizobia.

  4. 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.

  5. [Photosynthetic parameters and physiological indexes of Paris polyphylla var. yunnanensis influenced by arbuscular mycorrhizal fungi].

    Science.gov (United States)

    Wei, Zheng-xin; Guo, Dong-qin; Li, Hai-feng; Ding, Bo; Zhang, Jie; Zhou, Nong; Yu, Jie

    2015-10-01

    Through potted inoculation test at room temperature and indoor analysis, the photosynthetic parameters and physiological and biochemical indexes of Paris polyphylla var. yunnanensis were observed after 28 arbuscular mycorrhizal (AM) fungi were injected into the P. polyphylla var. yunnanensis growing in a sterile soil environment. The results showed that AM fungi established a good symbiosis with P. polyphylla var. yunnanensis. The AM fungi influenced the photosynthetic parameters and physiological and biochemical indexes of P. polyphylla var. yunnanensis. And the influences were varied depending on different AM fungi. The application of AM fungi improved photosynthesis intensity of P. polyphylla var. yunnanensis mesophyll cells, the contents of soluble protein and soluble sugar, protective enzyme activity of P. polyphylla var. yunnanensis leaf, which was beneficial to resist the adverse environment and promote the growth of P. polyphylla var. yunnanensis. Otherwise, there was a certain mutual selectivity between P. polyphylla var. yunnanensis and AM fungi. From the comprehensive effect of inoculation, Racocetra coralloidea, Scutellospora calospora, Claroideoglomus claroideum, S. pellucida and Rhizophagus clarus were the most suitable AM fungi to P. polyphylla var. yunnanensis when P. polyphylla var. yunnanensis was planted in the field.

  6. Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd.) Poir from Brazilian semi-arid.

    Science.gov (United States)

    de Souza, Tancredo Augusto Feitosa; Rodriguez-Echeverría, Susana; de Andrade, Leonaldo Alves; Freitas, Helena

    2016-01-01

    Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a) during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b) soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites.

  7. Arbuscular mycorrhizal fungi enhance soil carbon sequestration in the coalfields, northwest China

    Science.gov (United States)

    Wang, Zhi-Gang; Bi, Yin-Li; Jiang, Bin; Zhakypbek, Yryszhan; Peng, Su-Ping; Liu, Wen-Wen; Liu, Hao

    2016-10-01

    Carbon storage is affected by photosynthesis (Pn) and soil respiration (Rs), which have been studied extensively in natural and agricultural systems. However, the effects of Pn and Rs on carbon storages in the presence of arbuscular mycorrhizal fungi (AMF) in coalfields remain unclear. A field experiment was established in 2014 in Shendong coal mining subsidence area. The treatments comprised two inoculation levels (inoculated with or without 100 g AMF inoculums per seedlings) and four plant species [wild cherry (Prunus discadenia Koebne L.), cerasus humilis (Prunus dictyneura Diels L.), shiny leaf Yellow horn (Xanthoceras sorbifolium Bunge L.) and apricot (Armeniaca sibirica L.)]. AMF increased Pn of four species ranging from 15.3% to 33.1% and carbon storage, averaged by 17.2% compared to controls. Soil organic carbon (OC), easily extractable glomalin-relation soil protein (EE-GRSP), and total glomalin-relation soil protein (T-GRSP) were significantly increased by AMF treatment. The effect of AMF on the sensitivity of Rs depended on soil temperature. The results highlighted the exponential models to explain the responses of Rs to soil temperature, and for the first time quantified AMF caused carbon sequestration and Rs. Thus, to our knowledge, AMF is beneficial to ecosystems through facilitating carbon conservation in coalfield soils.

  8. The occurrence of arbuscular mycorrhizal fungi of the phylum Glomeromycota in Israeli soils

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2011-04-01

    Full Text Available In December 1997 and June-July 2000, 49 and 113 rhizosphere soil and root mixtures were collected, respectively, to determine the occurrence of arbuscular mycorrhizal fungi (AMF of the phylum Glomeromycota in different sites of Israel. Except for five samples taken from under cultivated plants, all the others came from under Ammophila arenaria and Oenothera drummondii colonizing sand dunes adjacent to the Mediterranean Sea. After a continuous cultivation of the mixtures in pot trap cultures with Plantago lanceolata as the plant host up to 2006 and their examination at least twice a year, spores of AMF were found in 41 and 103 cultures with the 1997 and 2000 soil and root mixtures, respectively. The spores represented 30 species and 8 undescribed morphotypes in 7 genera of the Glomeromycota. The AMF most frequently found in Israeli soils were Glomus aurantium and G. constrictum, followed by G. coronatum, G. gibbosum, an undescribed Glomus 178, and Scutellospora dipurpurescens. Up to 2001, 21 species of AMF were known to occur in Israel, and this paper increases this number to 33, of which 11 are new fungi for this country. Moreover, four species, G. aurantium, G. drummondii, G. walkeri and G. xanthium, were recently described as new for science based on spores isolated from Israeli soils. Additionally, the general distribution in the world of the formally described species found in Israel was presented.

  9. Recombination in Glomus intraradices, a supposed ancient asexual arbuscular mycorrhizal fungus

    Directory of Open Access Journals (Sweden)

    Sanders Ian R

    2009-01-01

    Full Text Available Abstract Background Arbuscular mycorrhizal fungi (AMF are important symbionts of most plant species, promoting plant diversity and productivity. This symbiosis is thought to have contributed to the early colonisation of land by plants. Morphological stasis over 400 million years and the lack of an observed sexual stage in any member of the phylum Glomeromycota led to the controversial suggestion of AMF being ancients asexuals. Evidence for recombination in AMF is contradictory. Results We addressed the question of recombination in the AMF Glomus intraradices by sequencing 11 polymorphic nuclear loci in 40 morphologically identical isolates from one field. Phylogenetic relationships among genotypes showed a reticulate network pattern providing a rationale to test for recombination. Five statistical tests predicted multiple recombinant regions in the genome of a core set of isolates. In contrast, five clonal lineages had fixed a large number of differences. Conclusion Our data show that AMF from one field have undergone recombination but that clonal lineages coexist. This finding has important consequences for understanding AMF evolution, co-evolution of AMF and plants and highlights the potential for commercially introduced AMF inoculum recombining with existing local populations. Finally, our results reconcile seemingly contradictory studies on whether AMF are clonal or form recombining populations.

  10. Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis.

    Science.gov (United States)

    Tisserant, Emilie; Malbreil, Mathilde; Kuo, Alan; Kohler, Annegret; Symeonidi, Aikaterini; Balestrini, Raffaella; Charron, Philippe; Duensing, Nina; Frei dit Frey, Nicolas; Gianinazzi-Pearson, Vivienne; Gilbert, Luz B; Handa, Yoshihiro; Herr, Joshua R; Hijri, Mohamed; Koul, Raman; Kawaguchi, Masayoshi; Krajinski, Franziska; Lammers, Peter J; Masclaux, Frederic G; Murat, Claude; Morin, Emmanuelle; Ndikumana, Steve; Pagni, Marco; Petitpierre, Denis; Requena, Natalia; Rosikiewicz, Pawel; Riley, Rohan; Saito, Katsuharu; San Clemente, Hélène; Shapiro, Harris; van Tuinen, Diederik; Bécard, Guillaume; Bonfante, Paola; Paszkowski, Uta; Shachar-Hill, Yair Y; Tuskan, Gerald A; Young, J Peter W; Young, Peter W; Sanders, Ian R; Henrissat, Bernard; Rensing, Stefan A; Grigoriev, Igor V; Corradi, Nicolas; Roux, Christophe; Martin, Francis

    2013-12-10

    The mutualistic symbiosis involving Glomeromycota, a distinctive phylum of early diverging Fungi, is widely hypothesized to have promoted the evolution of land plants during the middle Paleozoic. These arbuscular mycorrhizal fungi (AMF) perform vital functions in the phosphorus cycle that are fundamental to sustainable crop plant productivity. The unusual biological features of AMF have long fascinated evolutionary biologists. The coenocytic hyphae host a community of hundreds of nuclei and reproduce clonally through large multinucleated spores. It has been suggested that the AMF maintain a stable assemblage of several different genomes during the life cycle, but this genomic organization has been questioned. Here we introduce the 153-Mb haploid genome of Rhizophagus irregularis and its repertoire of 28,232 genes. The observed low level of genome polymorphism (0.43 SNP per kb) is not consistent with the occurrence of multiple, highly diverged genomes. The expansion of mating-related genes suggests the existence of cryptic sex-related processes. A comparison of gene categories confirms that R. irregularis is close to the Mucoromycotina. The AMF obligate biotrophy is not explained by genome erosion or any related loss of metabolic complexity in central metabolism, but is marked by a lack of genes encoding plant cell wall-degrading enzymes and of genes involved in toxin and thiamine synthesis. A battery of mycorrhiza-induced secreted proteins is expressed in symbiotic tissues. The present comprehensive repertoire of R. irregularis genes provides a basis for future research on symbiosis-related mechanisms in Glomeromycota.

  11. A history of the taxonomy and systematics of arbuscular mycorrhizal fungi belonging to the phylum Glomeromycota.

    Science.gov (United States)

    Stürmer, Sidney Luiz

    2012-05-01

    Arbuscular mycorrhizal fungi (AMF) are grouped in a monophyletic group, the phylum Glomeromycota. In this review, the history and complexity of the taxonomy and systematics of these obligate biotrophs is addressed by recognizing four periods. The initial discovery period (1845-1974) is characterized by description mainly of sporocarp-forming species and the proposal of a classification for these fungi. The following alpha taxonomy period (1975-1989) established a solid morphological basis for species identification and classification, resulting in a profuse description of new species and a need to standardize the nomenclature of spore subcellular structures. The cladistics period from 1990 to 2000 saw the first cladistic classification of AMF based on phenotypic characters only. At the end of this period, genetic characters played a role in defining taxa and elucidating evolutionary relationships within the group. The most recent phylogenetic synthesis period (2001 to present) started with the proposal of a new classification based on genetic characters using sequences of the multicopy rRNA genes.

  12. Clonality and recombination in the life history of an asexual arbuscular mycorrhizal fungus.

    Science.gov (United States)

    den Bakker, Henk C; Vankuren, Nicholas W; Morton, Joseph B; Pawlowska, Teresa E

    2010-11-01

    Arbuscular mycorrhizal (AM) fungi in the phylum Glomeromycota colonize roots of the majority of land plants and assist them in the uptake of mineral nutrients in exchange for plant-assimilated carbon. In the absence of sexual reproductive structures and with asexual spore morphology conserved since the Ordovician, Glomeromycota may be one of the oldest eukaryotic lineages that rely predominantly on asexual reproduction for gene transmission. Clonal population structure detected in the majority of AM fungi examined to date supports this hypothesis. However, evidence of recombination found in few local populations suggests that genetic exchanges may be more common in these organisms than is currently recognized. To explore the significance of clonal expansion versus genetic recombination in the life history of modern Glomeromycota, we examined the global population of a cosmopolitan fungus Glomus etunicatum and made inferences about the population structure and the occurrence of recombination in the history of this species. We sampled eight loci from 84 isolates. We found that although the global population of G. etunicatum showed a pattern of significant differentiation, several haplotypes had a broad geographic distribution spanning multiple continents. Molecular variation among the sampled isolates indicated an overwhelmingly clonal population structure and suggested that clonal expansion plays an important role in the ecological success of modern Glomeromycota. In contrast, a pattern of homoplasy consistent with a history of recombination suggested that gene exchanges are not completely absent from the life history of these organisms, although they are likely to be very rare.

  13. Mitochondrial large ribosomal subunit sequences are homogeneous within isolates of Glomus (arbuscular mycorrhizal fungi, Glomeromycota).

    Science.gov (United States)

    Raab, Philipp A; Brennwald, Annemarie; Redecker, Dirk

    2005-12-01

    Partial sequences of the mtLSU rDNA were obtained from the arbuscular mycorrhizal (AM) fungi Glomus proliferum (isolate DAOM 226389) and G. intraradices (isolates JJ291 and BEG75). The exon sequences of the two species showed regions of strong divergence. There was no evidence of intra-isolate sequence heterogeneity as it is found in variable regions of nuclear ribosomal genes of Glomeromycota. In G. intraradices JJ291, two introns were found in the partial LSU sequence. One of the introns contained an ORF for a putative site-specific homing endonuclease of the LAGLIDADG family. In G. intraradices BEG75, one of the introns was missing and the other had a DNA sequence distinct from JJ291. G. proliferum had no introns in the region sequenced. A PCR primer was designed to amplify the fragment of the mtLSU of a different, distinguishable G. intraradices genotype from colonized roots of a field sample. These mitochondrial gene sequences are the first reported from the phylum Glomeromycota. Our findings indicate that the intra-individual sequence heterogeneity of the Glomeromycota may be a peculiar feature of the nuclear genes. Therefore, mtLSU and its introns have the potential to be highly sensitive genetic markers for these fungi in the future.

  14. Arbuscular mycorrhizal fungi: new species and records in Northeast of Brazil

    Directory of Open Access Journals (Sweden)

    Danielle Karla Alves da Silva

    2014-10-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF comprise the largest association of plants and fungi in nature yet have only recently been considered within the context of conservation biology. The aim of this work was to document the occurrence of AMF species and highlight recent advances in our knowledge of their diversity in Northeast Brazil. This new information has been generated by the Sisbiota-Brazil Program (National System of Biodiversity Research and provides the basis for a discussion on the AMF species found in the region. The work included a bibliographic review of the records from natural and agricultural area plus data generated by collections made in natural areas in six of the nine northeastern states during the period 2010-2013. Overall we recorded 28 genera and 125 species of AMF. Of these, 11 were new species, 13 represented new records for Brazil and six were unique to the Northeast. This represents a 25% increase in our knowledge of the diversity of AMF in the region. We can now estimate that the Northeast represents about 50% of the AMF species described worldwide. This finding reinforces the need for more studies in areas that are poorly studied in order to extend our understanding of this biodiversity and to help to define future strategies for management and conservation.

  15. Crop rotation biomass and arbuscular mycorrhizal fungi effects on sugarcane yield

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosano, Edmilson Jose; Rossi, Fabricio; Guirado, Nivaldo; Teramoto, Juliana Rolim Salome [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicaba, SP (Brazil). Polo Regional Centro Sul; Azcon, Rozario [Consejo Superior de Investigaciones Cientificas (CSIC), Granada (Spain). Estacao Experimental de Zaidin; Cantarela, Heitor [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IAC), Campinas, SP (Brazil). Inst. Agronomico. Centro de Solos e Recursos Ambientais; Ambrosano, Glaucia Maria Bovi [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Fac. de Odontologia. Dept. de Odontologia Social], Email: ambrosano@apta.sp.gov.br; Schammass, Eliana Aparecida [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IZ), Nova Odessa, SP (Brazil). Inst. de Zootecnia; Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Ungaro, Maria Regina Goncalves [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IAC), Campinas, SP (Brazil). Inst. Agronomico. Centro de Plantas Graniferas

    2010-07-01

    Sugarcane (Saccharum spp.) is an important crop for sugar production and agro-energy purposes in Brazil. In the sugarcane production system after a 4- to 8-year cycle crop rotation may be used before replanting sugarcane to improve soil conditions and give an extra income. This study had the objective of characterizing the biomass and the natural colonization of arbuscular mycorrhizal fungi (AMF) of leguminous green manure and sunflower (Helianthus annuus L.) in rotation with sugarcane. Their effect on stalk and sugar yield of sugarcane cv. IAC 87-3396 grown subsequently was also studied. Cane yield was harvested in three subsequent cuttings. Peanut cv. IAC-Caiapo, sunflower cv. IAC-Uruguai and velvet bean (Mucuna aterrimum Piper and Tracy) were the rotational crops that resulted in the greater percentage of AMF. Sunflower was the specie that most extracted nutrients from the soil, followed by peanut cv. IAC-Tatu and mung bean (Vigna radiata L. Wilczek). The colonization with AMF had a positive correlation with sugarcane plant height, at the first cut (p = 0.01 and R = 0.52) but not with the stalk or cane yields. Sunflower was the rotational crop that brought about the greatest yield increase of the subsequent sugarcane crop: 46% increase in stalk yield and 50% in sugar yield compared with the control. Except for both peanut varieties, all rotational crops caused an increase in net income of the cropping system in the average of three sugarcane harvests. (author)

  16. TRANSITION METAL TRANSPORT IN PLANTS AND ASSOCIATED ENDOSYMBIONTS: ARBUSCULAR MYCORRHIZAL FUNGI AND RHIZOBIA

    Directory of Open Access Journals (Sweden)

    Manuel González-Guerrero

    2016-07-01

    Full Text Available Transition metals such as iron, copper, zinc, or molybdenum, are essential nutrients for plants. These elements are involved in almost every biological process, including photosynthesis, tolerance to biotic and abiotic stress, or symbiotic nitrogen fixation. However, plants often grow in soils with limiting metallic oligonutrient bioavailability. Consequently, to ensure the proper metal levels, plants have developed a complex metal uptake and distribution system, that not only involves the plant itself, but also its associated microorganisms. These microorganisms can simply increase metal solubility in soils and making them more accessible to the host plant, as well as induce the plant metal deficiency response, or deliver directly transition elements to cortical cells. Other, instead of providing metals can act as metal sinks, such as endosymbiotic rhizobia in legume nodules that requires relatively large amounts to carry out nitrogen fixation. In this review, we propose to do an overview of metal transport mechanisms in the plant-microbe system, emphasizing the role of arbuscular mycorrhizal fungi and endosymbiotic rhizobia.

  17. Role of Dual Inoculation of Rhizobium and Arbuscular Mycorrhizal (AM Fungi on Pulse Crops Production

    Directory of Open Access Journals (Sweden)

    Erneste HAVUGIMANA

    2016-01-01

    Full Text Available Legume crops are useful as human and animal feed, wood energy, and as soil-improving components of agricultural and agro forestry systems through its association with bio-fertilizers. The later have a potential environment friendly inputs that are supplemented for proper plant growth. Bio-fertilizers are preparations containing living cells of microorganisms that help crop plants in the uptake of nutrients by their interactions in the rhizosphere. Arbuscular mycorrhizal (AM fungi are beneficial symbionts for plant growth. They are associated with higher plants by a symbiotic association and benefit plants in the uptake of phosphorus nutrients, production of growth hormones, increase of proteins, lipids and sugars levels, helps in heavy metal binding, salinity tolerance and disease resistance. In nature symbiotic association of Rhizobium and leguminous plants fixes atmospheric nitrogen. Indeed, research has proved that the association of mycorrhizae fungi and Rhizobium, with pulse crops, increased the beneficial aspects comparatively more than their single associations with the host plants. This review focuses on the role of dual inoculation of AM fungi and Rhizobium on different pulse crops.

  18. Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Zarei, Mehdi [Department of Soil Science, College of Agriculture, University of Shiraz, Shiraz (Iran, Islamic Republic of); Hempel, Stefan, E-mail: hempel.stefan@googlemail.co [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany); Freie Universitaet Berlin, Institut fuer Biologie, Okologie der Pflanzen, Altensteinstrasse 6, 14195 Berlin (Germany); Wubet, Tesfaye; Schaefer, Tina [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany); Savaghebi, Gholamreza [Department of Soil Science Engineering, University College of Agriculture and Natural Resources, University of Tehran, Karaj (Iran, Islamic Republic of); Jouzani, Gholamreza Salehi; Nekouei, Mojtaba Khayam [Agricultural Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-1897, Karaj (Iran, Islamic Republic of); Buscot, Francois [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany)

    2010-08-15

    Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils' calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions. - The molecular diversity of AMF was found to be influenced by a combination of soil heavy metal and other soil chemical parameters.

  19. Relative importance of an arbuscular mycorrhizal fungus (Rhizophagus intraradices) and root hairs in plant drought tolerance.

    Science.gov (United States)

    Li, Tao; Lin, Ge; Zhang, Xin; Chen, Yongliang; Zhang, Shubin; Chen, Baodong

    2014-11-01

    Both arbuscular mycorrhizal (AM) fungi and root hairs play important roles in plant uptake of water and mineral nutrients. To reveal the relative importance of mycorrhiza and root hairs in plant water relations, a bald root barley (brb) mutant and its wild type (wt) were grown with or without inoculation of the AM fungus Rhizophagus intraradices under well-watered or drought conditions, and plant physiological traits relevant to drought stress resistance were recorded. The experimental results indicated that the AM fungus could almost compensate for the absence of root hairs under drought-stressed conditions. Moreover, phosphorus (P) concentration, leaf water potential, photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency were significantly increased by R. intraradices but not by root hairs, except for shoot P concentration and photosynthetic rate under the drought condition. Root hairs even significantly decreased root P concentration under drought stresses. These results confirm that AM fungi can enhance plant drought tolerance by improvement of P uptake and plant water relations, which subsequently promote plant photosynthetic performance and growth, while root hairs presumably contribute to the improvement of plant growth and photosynthetic capacity through an increase in shoot P concentration.

  20. Nitrogen-fixing bacteria, arbuscular mycorrhizal fungi, and the productivity and structure of prairie grassland communities.

    Science.gov (United States)

    Bauer, Jonathan T; Kleczewski, Nathan M; Bever, James D; Clay, Keith; Reynolds, Heather L

    2012-12-01

    Due to their complementary roles in meeting plant nutritional needs, arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (N(2)-fixers) may have synergistic effects on plant communities. Using greenhouse microcosms, we tested the effects of AMF, N(2)-fixers (symbiotic: rhizobia, and associative: Azospirillum brasilense), and their potential interactions on the productivity, diversity, and species composition of diverse tallgrass prairie communities and on the productivity of Panicum virgatum in monoculture. Our results demonstrate the importance of AMF and N(2)-fixers as drivers of plant community structure and function. In the communities, we found a positive effect of AMF on diversity and productivity, but a negative effect of N(2)-fixers on productivity. Both AMF and N(2)-fixers affected relative abundances of species. AMF shifted the communities from dominance by Elymus canadensis to Sorghastrum nutans, and seven other species increased in abundance with AMF, accounting for the increased diversity. N(2)-fixers led to increases in Astragalus canadensis and Desmanthus illinoense, two legumes that likely benefited from the presence of the appropriate rhizobia symbionts. Sorghastrum nutans declined 44 % in the presence of N(2)-fixers, with the most likely explanation being increased competition from legumes. Panicum monocultures were more productive with AMF, but showed no response to N(2)-fixers, although inference was constrained by low Azospirillum treatment effectivity. We did not find interactions between AMF and N(2)-fixers in communities or Panicum monocultures, indicating that short-term effects of these microbial functional groups are additive.

  1. Spatio-temporal variation of core and satellite arbuscular mycorrhizal fungus communities in Miscanthus giganteus

    Directory of Open Access Journals (Sweden)

    Christopher James Barnes

    2016-08-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time to shaping AMF communities associated with Miscanthus giganteus were determined over a 13 month period. In particular, the community was partitioned into core (abundant and persistent taxa and satellite (taxa with low abundance and persistence constituents and the drivers of community assembly for each determined. We show that AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses.

  2. Spatio-Temporal Variation of Core and Satellite Arbuscular Mycorrhizal Fungus Communities in Miscanthus giganteus

    Science.gov (United States)

    Barnes, Christopher J.; Burns, Caitlin A.; van der Gast, Christopher J.; McNamara, Niall P.; Bending, Gary D.

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time in shaping AMF communities associated with Miscanthus giganteus (a perennial grass originating from south-east Asia) were determined over a 13 months period. In particular, the community was partitioned into core (abundant and persistent taxa) and satellite (taxa with low abundance and persistence) constituents and the drivers of community assembly for each determined. β-diversity was exceptionally low across the 140 m line transects, and there was limited evidence of geographical scaling effects on the composition of the core, satellite or combined communities. However, AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses. PMID:27597844

  3. Enhanced Pb Absorption by Hordeum vulgare L. and Helianthus annuus L. Plants Inoculated with an Arbuscular Mycorrhizal Fungi Consortium.

    Science.gov (United States)

    Arias, Milton Senen Barcos; Peña-Cabriales, Juan José; Alarcón, Alejandro; Maldonado Vega, María

    2015-01-01

    The effect of an arbuscular mycorrhizal fungi (AMF) consortium conformed by (Glomus intraradices, Glomus albidum, Glomus diaphanum, and Glomus claroideum) on plant growth and absorption of Pb, Fe, Na, Ca, and (32)P in barley (Hordeum vulgare L.) and sunflower (Helianthus annuus L.) plants was evaluated. AMF-plants and controls were grown in a substrate amended with powdered Pb slag at proportions of 0, 10, 20, and 30% v/v equivalent to total Pb contents of 117; 5,337; 13,659, and 19,913 mg Pb kg(-1) substrate, respectively. Mycorrhizal root colonization values were 70, 94, 98, and 90%, for barley and 91, 97, 95, and 97%, for sunflower. AMF inoculum had positive repercussions on plant development of both crops. Mycorrhizal barley absorbed more Pb (40.4 mg Pb kg(-1)) shoot dry weight than non-colonized controls (26.5 mg Pb kg(-1)) when treated with a high Pb slag dosage. This increase was higher in roots than shoots (650.0 and 511.5 mg Pb kg(-1) root dry weight, respectively). A similar pattern was found in sunflower. Plants with AMF absorbed equal or lower amounts of Fe, Na and Ca than controls. H. vulgare absorbed more total P (1.0%) than H. annuus (0.9%). The arbuscular mycorrizal consortium enhanced Pb extraction by plants.

  4. Modelling Spatial Interactions in the Arbuscular Mycorrhizal Symbiosis using the Calculus of Wrapped Compartments

    CERN Document Server

    Calcagno, Cristina; Damiani, Ferruccio; Drocco, Maurizio; Sciacca, Eva; Spinella, Salvatore; Troina, Angelo; 10.4204/EPTCS.67.3

    2011-01-01

    Arbuscular mycorrhiza (AM) is the most wide-spread plant-fungus symbiosis on earth. Investigating this kind of symbiosis is considered one of the most promising ways to develop methods to nurture plants in more natural manners, avoiding the complex chemical productions used nowadays to produce artificial fertilizers. In previous work we used the Calculus of Wrapped Compartments (CWC) to investigate different phases of the AM symbiosis. In this paper, we continue this line of research by modelling the colonisation of the plant root cells by the fungal hyphae spreading in the soil. This study requires the description of some spatial interaction. Although CWC has no explicit feature modelling a spatial geometry, the compartment labelling feature can be effectively exploited to define a discrete surface topology outlining the relevant sectors which determine the spatial properties of the system under consideration. Different situations and interesting spatial properties can be modelled and analysed in such a ligh...

  5. Bacteria associated with arbuscular mycorrhizal fungi within roots of plants growing in a soil highly contaminated with aliphatic and aromatic petroleum hydrocarbons.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2014-09-01

    Arbuscular mycorrhizal fungi (AMF) belong to phylum Glomeromycota, an early divergent fungal lineage forming symbiosis with plant roots. Many reports have documented that bacteria are intimately associated with AMF mycelia in the soil. However, the role of these bacteria remains unclear and their diversity within intraradical AMF structures has yet to be explored. We aim to assess the bacterial communities associated within intraradical propagules (vesicles and intraradical spores) harvested from roots of plant growing in the sediments of an extremely petroleum hydrocarbon-polluted basin. Solidago rugosa roots were sampled, surface-sterilized, and microdissected. Eleven propagules were randomly collected and individually subjected to whole-genome amplification, followed by PCRs, cloning, and sequencing targeting fungal and bacterial rDNA. Ribotyping of the 11 propagules showed that at least five different AMF OTUs could be present in S. rugosa roots, while 16S rRNA ribotyping of six of the 11 different propagules showed a surprisingly high bacterial richness associated with the AMF within plant roots. Most dominant bacterial OTUs belonged to Sphingomonas sp., Pseudomonas sp., Massilia sp., and Methylobacterium sp. This study provides the first evidence of the bacterial diversity associated with AMF propagules within the roots of plants growing in extremely petroleum hydrocarbon-polluted conditions.

  6. Phosphate transport by hyphae of field communities of arbuscular mycorrhizal fungi at two levels of P fertilization

    DEFF Research Database (Denmark)

    Thingstrup, I.; Kahiluoto, H.; Jakobsen, I.

    2000-01-01

    This study was conducted to elucidate the effect of P fertilisation on the function of field communities of arbuscular mycorrhizal fungi (AMF) measured as P transport to flax. Two methods were applied to soil from a long-term field experiment with NaHCO3-extractable soil P levels of 24 and 50 mg kg......(-1) in an experiment under controlled conditions: i) Measurement of plant growth and P uptake in the presence or absence of the fungicide benomyl and ii) measurement of hyphal P transport from a root-free compartment labelled with P-32. Benomyl successfully prevented mycorrhizal function....... The absolute contribution of AMF to plant P uptake was of the same magnitude with or without P fertilisation at 27 days after sowing. Therefore, even though plants grown at the higher soil P level had greater P uptake, the relative contribution of AMF to P uptake was greater at the lower P level than...

  7. Community structure of arbuscular mycorrhizal fungi associated to Veronica rechingeri at the Anguran zinc and lead mining region

    Energy Technology Data Exchange (ETDEWEB)

    Zarei, M. [Department of Soil Science Engineering, Soil and Water Engineering Faculty, University College of Agriculture and Natural Resources, University of Tehran, Karaj (Iran, Islamic Republic of)], E-mail: mehdizarei20@yahoo.ca; Koenig, S. [UFZ Helmholtz Center for Environmental Research Leipzig-Halle Ltd, Department of Soil Ecology, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)], E-mail: stephan.koenig@ufz.de; Hempel, S. [UFZ Helmholtz Center for Environmental Research Leipzig-Halle Ltd, Department of Soil Ecology, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)], E-mail: hempel.stefan@gmail.com; Nekouei, M. Khayam [Agricultural Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-1897, Karaj (Iran, Islamic Republic of)], E-mail: Khayam@abrii.ac.ir; Savaghebi, Gh. [Department of Soil Science Engineering, Soil and Water Engineering Faculty, University College of Agriculture and Natural Resources, University of Tehran, Karaj (Iran, Islamic Republic of)], E-mail: Savagheb@ut.ac.ir; Buscot, F. [UFZ Helmholtz Center for Environmental Research Leipzig-Halle Ltd, Department of Soil Ecology, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)], E-mail: francois.buscot@ufz.de

    2008-12-15

    Root colonization and diversity of arbuscular mycorrhizal fungi (AMF) were analyzed in Veronica rechingeri growing in heavy metal (HM) and non-polluted soils of the Anguran Zn and Pb mining region (Iran). Three species could be separated morphologically, while phylogenetic analyses after PCR amplification of the ITS region followed by RFLP and sequencing revealed seven different AMF sequence types all within the genus Glomus. Rarefaction analysis confirmed exhaustive molecular characterization of the AMF diversity present within root samples. Increasing heavy metal contamination between the sites studied was accompanied by a decrease in AMF spore numbers, mycorrhizal colonization parameters and the number of AMF sequence types colonizing the roots. Some AMF sequence types were only found at sites with the highest and lowest soil HM contents, respectively. - The increase in soil heavy metal content between sites was accompanied by a decrease in mycorrhization parameters, spore numbers and AMF molecular diversity.

  8. Effect of Rhizobium and arbuscular mycorrhizal fungi inoculation on electrolyte leakage in Phaseolus vulgaris roots overexpressing RbohB.

    Science.gov (United States)

    Arthikala, Manoj-Kumar; Nava, Noreide; Quinto, Carmen

    2015-01-01

    Respiratory oxidative burst homolog (RBOH)-mediated reactive oxygen species (ROS) regulate a wide range of biological functions in plants. They play a critical role in the symbiosis between legumes and nitrogen-fixing bacteria or arbuscular mycorrhizal (AM) fungi. For instance, overexpression of PvRbohB enhances nodule numbers, but reduces mycorrhizal colonization in Phaseolus vulgaris hairy roots and downregulation has the opposite effect. In the present study, we assessed the effect of both rhizobia and AM fungi on electrolyte leakage in transgenic P. vulgaris roots overexpressing (OE) PvRbohB. We demonstrate that elevated levels of electrolyte leakage in uninoculated PvRbohB-OE transgenic roots were alleviated by either Rhizobium or AM fungi symbiosis, with the latter interaction having the greater effect. These results suggest that symbiont colonization reduces ROS elevated electrolyte leakage in P. vulgaris root cells.

  9. Remediation of PAH-contaminated soil by the combination of tall fescue, arbuscular mycorrhizal fungus and epigeic earthworms.

    Science.gov (United States)

    Lu, Yan-Fei; Lu, Mang

    2015-03-21

    A 120-day experiment was performed to investigate the effect of a multi-component bioremediation system consisting of tall fescue (Festuca arundinacea), arbuscular mycorrhizal fungus (AMF) (Glomus caledoniun L.), and epigeic earthworms (Eisenia foetida) for cleaning up polycyclic aromatic hydrocarbons (PAHs)-contaminated soil. Inoculation with AMF and/or earthworms increased plant yield and PAH accumulation in plants. However, PAH uptake by tall fescue accounted for a negligible portion of soil PAH removal. Mycorrhizal tall fescue significantly enhanced PAH dissipation, PAH degrader density and polyphenol oxidase activity in soil. The highest PAH dissipation (93.4%) was observed in the combination treatment: i.e., AMF+earthworms+tall fescue, in which the soil PAH concentration decreased from an initial value of 620 to 41 mg kg(-1) in 120 days. This concentration is below the threshold level required for Chinese soil PAH quality (45 mg kg(-1) dry weight) for residential use.

  10. Phosphorus uptake of an arbuscular mycorrhizal fungus is not effected by the biocontrol bacterium ¤Burkholderia cepacia¤

    DEFF Research Database (Denmark)

    Ravnskov, S.; Larsen, J.; Jakobsen, I.

    2002-01-01

    the amount of branched PLFAs suggesting a reduction in the population of Gram-positive bacteria in these cases. In conclusion, the B. cepacia seems to have no impact on neither mycorrhiza formation nor on the functioning of the AM fungus G. intraradices in terms of P transport, whereas our results suggest......The biocontrol bacterium Burkholderia cepacia is known to suppress a broad range of root pathogenic fungi, while its impact on other beneficial non-target organisms such as arbuscular mycorrhizal (AM) fungi is unknown. Direct interactions between five B. cepacia strains and the AM fungus, Glomus...

  11. 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 reducing...... after AM fungi inoculation, roots were challenged with P. aphanidermatum. Variables evaluated at each harvest were root colonization levels of the interacting fungi, plant growth responses, and expression of a plant pathogenesis related protein gene (PR-1). All of the tested AM fungi caused marked...

  12. Grain yield and arsenic uptake of upland rice inoculated with arbuscular mycorrhizal fungi in As-spiked soils.

    Science.gov (United States)

    Wu, Fuyong; Hu, Junli; Wu, Shengchun; Wong, Ming Hung

    2015-06-01

    A pot trial was conducted to investigate the effects of three arbuscular mycorrhizal (AM) fungi species, including Glomus geosporum BGC HUN02C, G. versiforme BGC GD01B, and G. mosseae BGC GD01A, on grain yield and arsenic (As) uptake of upland rice (Zhonghan 221) in As-spiked soils. Moderate levels of AM colonization (24.1-63.1 %) were recorded in the roots of upland rice, and up to 70 mg kg(-1) As in soils did not seem to inhibit mycorrhizal colonization. Positive mycorrhizal growth effects in grain, husk, straw, and root of the upland rice, especially under high level (70 mg kg(-1)) of As in soils, were apparent. Although the effects varied among species of AM fungi, inoculation of AM fungi apparently enhanced grain yield of upland rice without increasing grain As concentrations in As-spiked soils, indicating that AM fungi could alleviate adverse effects on the upland rice caused by As in soils. The present results also show that mycorrhizal inoculation significantly (p < 0.05) decreased As concentrations in husk, straw, and root in soils added with 70 mg kg(-1) As. The present results suggest that AM fungi are able to mitigate the adverse effects with enhancing rice production when growing in As-contaminated soils.

  13. Fungos micorrízicos arbusculares no crescimento e nutrição de mudas de jenipapeiro Arbuscular mycorrhizal fungi in the growth and nutrition of jenipapo fruit tree seedlings

    Directory of Open Access Journals (Sweden)

    Ana Cristina Fermino Soares

    2012-03-01

    Full Text Available Alguns trabalhos têm demonstrado que a inoculação de fungos micorrízicos arbusculares (FMA na produção de mudas apresenta grande potencial para o desenvolvimento de um cultivo racional e eficiente de mudas de fruteiras. O objetivo neste trabalho foi avaliar a inoculação de fungos micorrízicos arbusculares no crescimento e nutrição de mudas de jenipapeiro (Genipa americana L.. O experimento foi conduzido em blocos casualizados, avaliando-se seis espécies fúngicas: Glomus clarum, Glomus etunicatum, Glomus manihots, Gigaspora albida, Acaulospora scrobiculata e Scutellospora heterogama, com dez repetições. As espécies A. scrobiculata, G. clarum e G. etunicatum colonizaram mais intensamente o sistema radicular e promoveram melhor desenvolvimento das mudas de jenipapeiro quando comparados a G. manihots e G. albida. O fungo G. etunicatum destacou-se, promovendo incrementos na altura (44,4%; no diâmetro do caule (63,6%; na produção de biomassa seca na parte aérea (288,8%, nas raízes (248,7% e na área foliar (315,7% em comparação às mudas controle. Com exceção de Mn e Fe, mudas inoculadas apresentaram teores de nutrientes superior às mudas controle. As mudas que receberam inóculo de S. heterogama apresentaram crescimento e teor de nutrientes similares aos das mudas controle. A colonização micorrízica correlacionou-se positivamente com os teores de N, P, K, Mg e Cu e negativamente com os teores de Fe e Mn nas folhas das mudas de jenipapeiro. O jenipapeiro é uma planta responsiva aos FMA e a inoculação beneficiou o crescimento e a nutrição das mudas.Some studies have shown that inoculation with arbuscular mycorrhizal fungi (AMF in seedling production has great potential for developing a rational and efficient cultivation of fruit tree seedlings. The objective of this study was to evaluate the effect of inoculation of arbuscular mycorrhizal fungi on growth and nutrition of seedlings of genipap (Genipa americana L.. The

  14. Soil solarization reduces arbuscular mycorrhizal fungi as a consequence of weed suppression.

    Science.gov (United States)

    Schreiner, P R; Ivors, K L; Pinkerton, J N

    2001-12-01

    Soil solarization, the process of heating soil by covering fields with clear plastic, is a promising method to reduce populations of soilborne pests and weeds without the use of pesticides. However, the destruction of beneficial organisms such as arbuscular mycorrhizal (AM) fungi also may occur, thereby reducing positive effects of solarization. We compared the effects of solarization and chemical fumigants on the survival of indigenous AM fungi in 1995 and 1996. The infectivity of AM fungi was monitored before and after solarization using a greenhouse bioassay with Sorghum bicolor L. for both years. AM colonization of roots was also monitored in the field 8 months after solarization in 1995. Weed densities were measured 8 months after treatment in 1996. Solarization increased the average daily soil temperature 6-10°C and the maximum soil temperature reached by 10-16°C (5-20 cm depth). Solarization did not reduce the infectivity of AM fungi immediately after the solarization period in either year, as determined by the greenhouse bioassay. Infectivity was greatly reduced in solarized plots 8 months after solarization (over winter) in both years as assessed in the field (1995) or with the greenhouse bioassay (1996). Fumigation with metam sodium at 930 l ha(-1) (350 kg active ingredient ha(-1)) reduced the infectivity of AM fungi in both years, and fumigation with methyl bromide at 800 kg ha(-1) eliminated infection by AM fungi. Solarization was as effective as methyl bromide and metam sodium at 930 l ha(-1) in controlling winter annual weeds measured 8 months after treatment. Solarization apparently reduced AM fungi in soil indirectly by reducing weed populations that maintained infective propagules over the winter. Fumigation with metam sodium or methyl bromide directly reduced AM fungi in soil.

  15. Propagules of arbuscular mycorrhizal fungi in a secondary dry forest of Oaxaca, Mexico.

    Science.gov (United States)

    Guadarrama, Patricia; Castillo-Argüero, Silvia; Ramos-Zapata, José A; Camargo-Ricalde, Sara L; Alvarez-Sánchez, Javier

    2008-03-01

    Plant cover loss due to changes in land use promotes a decrease in spore diversity of arbuscular mycorrhizal fungi (AMF), viable mycelium and, therefore, in AMF colonization, this has an influence in community diversity and, as a consequence, in its recovery. To evaluate different AMF propagules, nine plots in a tropical dry forest with secondary vegetation were selected: 0, 1, 7, 10, 14, 18, 22, 25, and 27 years after abandonment in Nizanda, Oaxaca, Mexico. The secondary vegetation with different stages of development is a consequence of slash and burn agriculture, and posterior abandonment. Soil samples (six per plot) were collected and percentage of AMF field colonization, extrarradical mycelium, viable spore density, infectivity and most probable number (MPN) ofAMF propagules were quantified through a bioassay. Means for field colonization ranged between 40% and 70%, mean of total mycelium length was 15.7 +/- 1.88 mg(-1) dry soil, with significant differences between plots; however, more than 40% of extracted mycelium was not viable, between 60 and 456 spores in 100 g of dry soil were recorded, but more than 64% showed some kind of damage. Infectivity values fluctuated between 20% and 50%, while MPN showed a mean value of 85.42 +/- 44.17 propagules (100 g dry soil). We conclude that secondary communities generated by elimination of vegetation with agricultural purposes in a dry forest in Nizanda do not show elimination of propagules, probably as a consequence of the low input agriculture practices in this area, which may encourage natural regeneration.

  16. Do arbuscular mycorrhizal fungi affect cadmium uptake kinetics, subcellular distribution and chemical forms in rice?

    Science.gov (United States)

    Li, Hui; Luo, Na; Zhang, Li Jun; Zhao, Hai Ming; Li, Yan Wen; Cai, Quan Ying; Wong, Ming Hung; Mo, Ce Hui

    2016-11-15

    Rice (Oryza sativa L.) plants were inoculated with two species of arbuscular mycorrhizal fungi (AMF) - Rhizophagus intraradices (RI) and Funneliformis mosseae (FM) and grown for 60days to ensure strong colonization. Subsequently, a short-term hydroponic experiment was carried out to investigate the effects of AMF on cadmium (Cd) uptake kinetics, subcellular distribution and chemical forms in rice exposed to six Cd levels (0, 0.005, 0.01, 0.025, 0.05, 0.1mM) for three days. The results showed that the uptake kinetics of Cd fitted the Michaelis-Menten model well (R(2)>0.89). AMF significantly decreased the Cd concentrations both in shoots and roots in Cd solutions. Furthermore, the decrement of Cd concentrations by FM was significantly higher than RI treatment in roots. AMF reduced the Cd concentrations markedly in the cell wall fractions at high Cd substrate (≥0.025mM). The main subcellular fraction contributed to Cd detoxification was cell wall at low Cd substrate (<0.05mM), while vacuoles at high Cd substrate (≥0.05mM). Moreover, the concentrations and proportions of Cd in inorganic and water-soluble form also reduced by AMF colonization at high Cd substrate (≥0.05mM), both in shoots and roots. This suggested that AMF could convert Cd into inactive forms which were less toxic. Therefore, AMF could enhance rice resistance to Cd through altering subcellular distribution and chemical forms of Cd in rice.

  17. Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions

    Science.gov (United States)

    Cely, Martha V. T.; de Oliveira, Admilton G.; de Freitas, Vanessa F.; de Luca, Marcelo B.; Barazetti, André R.; dos Santos, Igor M. O.; Gionco, Barbara; Garcia, Guilherme V.; Prete, Cássio E. C.; Andrade, Galdino

    2016-01-01

    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, 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 of AMF 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 nutrient supply in soybean (Glycine max L.) and cotton (Gossypium hirsutum L.) when compared with conventional chemical fertilization under field conditions. The experiments were carried out in a completely randomized block design with five treatments: Fertilizer, AMF, AMF with Fertilizer, AMF with 1/2 Fertilizer, and the Control with non-inoculated and non-fertilized plants. The parameters evaluated were AMF root colonization and effect of inoculation on plant growth, nutrient absorption and yield. The results showed that AMF inoculation increased around 20 % of root colonization in both soybean and cotton; nutrients analyses in vegetal tissues showed increase of P and nitrogen content in inoculated plants, these results reflect in a higher yield. Our results showed that, AMF inoculation increase the effectiveness of fertilizer application in soybean and reduce the fertilizer dosage in cotton. PMID:27303367

  18. Does wheat genetically modified for disease resistance affect root-colonizing pseudomonads and arbuscular mycorrhizal fungi?

    Directory of Open Access Journals (Sweden)

    Joana Beatrice Meyer

    Full Text Available This study aimed to evaluate the impact of genetically modified (GM wheat with introduced pm3b mildew resistance transgene, on two types of root-colonizing microorganisms, namely pseudomonads and arbuscular mycorrhizal fungi (AMF. Our investigations were carried out in field trials over three field seasons and at two locations. Serial dilution in selective King's B medium and microscopy were used to assess the abundance of cultivable pseudomonads and AMF, respectively. We developed a denaturing gradient gel electrophoresis (DGGE method to characterize the diversity of the pqqC gene, which is involved in Pseudomonas phosphate solubilization. A major result was that in the first field season Pseudomonas abundances and diversity on roots of GM pm3b lines, but also on non-GM sister lines were different from those of the parental lines and conventional wheat cultivars. This indicates a strong effect of the procedures by which these plants were created, as GM and sister lines were generated via tissue cultures and propagated in the greenhouse. Moreover, Pseudomonas population sizes and DGGE profiles varied considerably between individual GM lines with different genomic locations of the pm3b transgene. At individual time points, differences in Pseudomonas and AMF accumulation between GM and control lines were detected, but they were not consistent and much less pronounced than differences detected between young and old plants, different conventional wheat cultivars or at different locations and field seasons. Thus, we conclude that impacts of GM wheat on plant-beneficial root-colonizing microorganisms are minor and not of ecological importance. The cultivation-independent pqqC-DGGE approach proved to be a useful tool for monitoring the dynamics of Pseudomonas populations in a wheat field and even sensitive enough for detecting population responses to altered plant physiology.

  19. Arbuscular mycorrhizal fungi alleviate oxidative stress induced by ADOR and enhance antioxidant responses of tomato plants.

    Science.gov (United States)

    García-Sánchez, Mercedes; Palma, José Manuel; Ocampo, Juan Antonio; García-Romera, Inmaculada; Aranda, Elisabet

    2014-03-15

    The behaviour of tomato plants inoculated with arbuscular mycorrhizal (AM) fungi grown in the presence of aqueous extracts from dry olive residue (ADOR) was studied in order to understand how this symbiotic relationship helps plants to cope with oxidative stress caused by ADOR. The influence of AM symbiosis on plant growth and other physiological parameters was also studied. Tomato plants were inoculated with the AM fungus Funneliformis mosseae and were grown in the presence of ADOR bioremediated and non-bioremediated by Coriolopsis floccosa and Penicillium chrysogenum-10. The antioxidant response as well as parameters of oxidative damage were examined in roots and leaves. The data showed a significant increase in the biomass of AM plant growth in the presence of ADOR, regardless of whether it was bioremediated. The establishment and development of the symbiosis were negatively affected after plants were exposed to ADOR. No differences were observed in the relative water content (RWC) or PS II efficiency between non-AM and AM plants. The increase in the enzymatic activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione-S-transferase (GST; EC 2.5.1.18) were simultaneous to the reduction of MDA levels and H2O2 content in AM root growth in the presence of ADOR. Similar H2O2 levels were observed among non-AM and AM plants, although only AM plants showed reduced lipid peroxidation content, probably due to the involvement of antioxidant enzymes. The results highlight how the application of both bioremediated ADOR and AM fungi can alleviate the oxidative stress conditions, improving the growth and development of tomato plants.

  20. Arbuscular mycorrhizal colonization, plant chemistry, and aboveground herbivory on Senecio jacobaea

    Science.gov (United States)

    Reidinger, Stefan; Eschen, René; Gange, Alan C.; Finch, Paul; Bezemer, T. Martijn

    2012-01-01

    Arbuscular mycorrhizal fungi (AMF) can affect insect herbivores by changing plant growth and chemistry. However, many factors can influence the symbiotic relationship between plant and fungus, potentially obscuring experimental treatments and ecosystem impacts. In a field experiment, we assessed AMF colonization levels of individual ragwort ( Senecio jacobaea) plants growing in grassland plots that were originally sown with 15 or 4 plant species, or were unsown. We measured the concentrations of carbon, nitrogen and pyrrolizidine alkaloids (PAs), and assessed the presence of aboveground insect herbivores on the sampled plants. Total AMF colonization and colonization by arbuscules was lower in plots sown with 15 species than in plots sown with 4 species and unsown plots. AMF colonization was positively related to the cover of oxeye daisy ( Leucanthemum vulgare) and a positive relationship between colonization by arbuscules and the occurrence of a specialist seed-feeding fly ( Pegohylemyia seneciella) was found. The occurrence of stem-boring, leaf-mining and sap-sucking insects was not affected by AMF colonization. Total PA concentrations were negatively related to colonization levels by vesicles, but did not differ among the sowing treatments. No single factor explained the observed differences in AMF colonization among the sowing treatments or insect herbivore occurrence on S. jacobaea. However, correlations across the treatments suggest that some of the variation was due to the abundance of one plant species, which is known to stimulate AMF colonization of neighbouring plants, while AMF colonization was related to the occurrence of a specialist insect herbivore. Our results thus illustrate that in natural systems, the ecosystem impact of AMF through their influence on the occurrence of specialist insects can be recognised, but they also highlight the confounding effect of neighbouring plant species identity. Hence, our results emphasise the importance of field

  1. The Potential Role of Arbuscular Mycorrhizal Fungi in the Restoration of Degraded Lands

    Science.gov (United States)

    Asmelash, Fisseha; Bekele, Tamrat; Birhane, Emiru

    2016-01-01

    Experiences worldwide reveal that degraded lands restoration projects achieve little success or fail. Hence, understanding the underlying causes and accordingly, devising appropriate restoration mechanisms is crucial. In doing so, the ever-increasing aspiration and global commitments in degraded lands restoration could be realized. Here we explain that arbuscular mycorrhizal fungi (AMF) biotechnology is a potential mechanism to significantly improve the restoration success of degraded lands. There are abundant scientific evidences to demonstrate that AMF significantly improve soil attributes, increase above and belowground biodiversity, significantly improve tree/shrub seedlings survival, growth and establishment on moisture and nutrient stressed soils. AMF have also been shown to drive plant succession and may prevent invasion by alien species. The very few conditions where infective AMF are low in abundance and diversity is when the soil erodes, is disturbed and is devoid of vegetation cover. These are all common features of degraded lands. Meanwhile, degraded lands harbor low levels of infective AMF abundance and diversity. Therefore, the successful restoration of infective AMF can potentially improve the restoration success of degraded lands. Better AMF inoculation effects result when inocula are composed of native fungi instead of exotics, early seral instead of late seral fungi, and are consortia instead of few or single species. Future research efforts should focus on AMF effect on plant community primary productivity and plant competition. Further investigation focusing on forest ecosystems, and carried out at the field condition is highly recommended. Devising cheap and ethically widely accepted inocula production methods and better ways of AMF in situ management for effective restoration of degraded lands will also remain to be important research areas. PMID:27507960

  2. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Paudel, Shishir; Longcore, Travis; MacDonald, Beau; McCormick, Melissa K; Szlavecz, Katalin; Wilson, Gail W T; Loss, Scot R

    2016-03-01

    A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms' effects on AMF and (2) the factors that determine the outcomes of earthworm-AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant-AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

  3. [Ecological distribution of arbuscular mycorrhizal fungi in alpine grasslands of Tibet Plateau].

    Science.gov (United States)

    Cai, Xiao-bu; Peng, Yue-lin; Gai, Jing-ping

    2010-10-01

    Seventy soil samples with the roots of 37 dominant or common plant species on the grasslands in south and north Tibet Plateau were collected to study the ecological distribution of arbuscular mycorrhizal (AM) fungi in the investigation area. A total of 35 AM fungi species belonging to 5 genera were isolated, among which, 18 species belonged to Glomus, 9 species belonged to Acaulospora, 6 species belonged to Scutellospora, 1 species belonged to Entrophospora, and 1 species belonged to Paraglomus. There were 23 AM fungi species belonging to 4 genera isolated from south Tibet, and 22 species belonging to 4 genera from north Tibet. The Shannon diversity index of AM fungi in south and north Tibet Plateau was 2.31 and 2.75, respectively, and the spore density and species richness were significantly higher in north Tibet than in south Tibet. In different ecological zones, lesser AM fungi common species were found, species distribution was more site-specific, and different dominant species were observed. In alpine grassland, mountain meadow, and alpine meadow, the Shannon index of AM fungi was 1.91, 1.83, and 1.80, respectively; while in severely degraded temperate grassland, this index was only 1.64. The highest species richness of AM fungi occurred at the altitude of 4000-4600 m, but the highest Shannon index and species evenness occurred at the altitude of 4600-5220 m, with the values being 2.42 and 0.79, respectively. At all altitudes, Glomus was the dominant genus, and its relative abundance was higher when the altitude was below 4000 m. Acaulospora was mainly observed at the altitudes higher than 4000 m, Scutellospora was mainly distributed at the altitude 3500-5220 m, Paraglomus mainly occurred in the north alpine meadow with an altitude of 4000-5220 m and occasionally in the alpine steppe, whereas Entrophospora was only found in the south temperate grassland with an altitude of 3500-3700 m.

  4. Taking mycocentrism seriously: mycorrhizal fungal and plant responses to elevated CO2

    NARCIS (Netherlands)

    Alberton, O.; Kuyper, T.W.; Gorissen, A.

    2005-01-01

    The aim here was to separately assess mycorrhizal fungal and plant responses under elevated atmospheric CO2, and to test a mycocentric model that assumes that increased carbon availability to the fungus will not automatically feed back to enhanced plant growth performance. Meta-analyses were applied

  5. On-farm production of arbuscular mycorrhizal funus inoculum in compost and vermiculite mixtures: results of on-farm demonstrations and impact of compost microbiological quality

    Science.gov (United States)

    The sustainability and profitability of many agricultural systems can be enhanced through the utilization of inoculum of arbuscular mycorrhizal fungi. Inocula are commercially available, but inoculum can also be produced on-farm in mixtures of compost and vermiculite with a nurse host plant. Demon...

  6. A comparison of the development and metabolic activity of mycorrhizas formed by arbuscular mycorrhizal fungi from different genera on two tropical forage legumes

    NARCIS (Netherlands)

    Boddington, C.L.; Dodd, J.C.

    1998-01-01

    Two glasshouse experiments were done to assess the development and metabolic activity of mycorrhizas formed by isolates of arbuscular mycorrhizal fungi (AMF) from three different genera, Acaulospora, Gigaspora and Glomus on either Pueraria phaseoloides L. or Desmodium ovalifolium L. plants. The seco

  7. Influence of host plants and soil diluents on arbuscular mycorrhizal fungus propagation for on-farm inoculum production using leaf litter compost and agrowastes

    Science.gov (United States)

    Arbuscular mycorrhizal (AM) fungi (Claroideoglomus etunicatum NNT10, C. etunicatum PBT03 and Funneliformis mosseae RYA08) were propagated using different culture materials (sterile sandy soil by itself or mixed 1:1 (v/v) with clay-brick granules, rice husk charcoal, or vermiculite) and host plants (...

  8. Depletion of soil mineral N by roots of ¤Cucumis sativus¤ L. colonized or not by arbuscular mycorrhizal fungi

    DEFF Research Database (Denmark)

    Johansen, A.

    1999-01-01

    Two experiments were conducted where Cucumis sativus were grown in uncompartmented pots either alone or in symbiosis with Glomus intraradices Schenck and Smith (Experiment 1) or Glomus sp. (Experiment 2) in order to investigate if root colonization by arbuscular mycorrhizal (AM) fungi has an effect...

  9. Genetic diversity and host plant preferences revealed by simple sequence repeat and mitochondrial markers in a population of the arbuscular mycorrhizal fungus Glomus intraradices

    NARCIS (Netherlands)

    Croll, D.; Wille, L.; Gamper, H.A.; Mathimaran, N.; Lammers, P.J.; Corradi, N.; Sanders, I.R.

    2008-01-01

    Arbuscular mycorrhizal fungi (AMF) are important symbionts of plants that improve plant nutrient acquisition and promote plant diversity. Although within-species genetic differences among AMF have been shown to differentially affect plant growth, very little is actually known about the degree of gen

  10. Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters

    DEFF Research Database (Denmark)

    Sawers, Ruairidh J. H.; Svane, Simon; Quan, Clement

    2017-01-01

    Plant interactions with arbuscular mycorrhizal fungi have long attracted interest for their potential to promote more efficient use of mineral resources in agriculture. Their use, however, remains limited by a lack of understanding of the processes that determine the outcome of the symbiosis. In ...

  11. Influencia de diferentes especies de fungo micorrizico arbuscular no desenvolvimento do crisântemo Influence of different species of arbuscular mycorrhizal fungi on chrysanthemum growth

    Directory of Open Access Journals (Sweden)

    Adriana Parada Dias da Silveira

    1996-01-01

    Full Text Available Com o objetivo de verificar o desenvolvimento e florescimento do crisântemo (Dendranthema grandiflora na presença de micorriza arbuscular, foi instalado, em casa de vegetação, um experimento, empregando-se os fungos Gigaspora margarita, Glomus leptotichum, Glomus macrocarpum e Scutellospora heterogama. Utilizou-se terra roxa estruturada, da Série Luiz de Queiroz, esterilizada (por autoclavagem e não esterilizada. No florescimento, colheram-se as plantas e determinaram-se a altura, a matéria seca da parte aérea, a matéria fresca da raiz, o teor de P e K na parte aérea, a colonização micorrízica e o número de esporos do fungo micorrízico. O desenvolvimento e o florescimento foram favorecidos pela inoculação de G. leptotichum e G.macrocarpum, quando as plantas foram cultivadas em solo esterilizado, superando o efeito dos fungos micorrízicos nativos. Entretanto, no solo não esterilizado, a inoculação dessas espécies de fungo não promoveu aumento no desenvolvimento da planta.A greenhouse experiment was conducted to verify the effect of arbuscular mycorrhiza on growth and flowering of chrysanthemum. Rooted plants were inoculated with Gigaspora margarita, Glomus leptotichum, Glomus macrocarpum e Scutellospora heterogama or non-inoculated. Plants were grown in a autoclave sterilized, and non-sterilized soil of the type "Terra Roxa Estruturada". At the flowering stage, plants were harvested and measured for plant height, shoot dry matter, root fresh matter, shoot P and K content, mycorrhizal root colonization and number of mycorrhizal fungi spores. Plants colonized with G.leptotichum and G. macrocarpum presented higher growth and flowering than control plants, in sterilized soil, overcoming the effect of native mycorrhizal fungi. However, there was no effect of introduced mycorrhizal fungi on non-sterilized soil.

  12. 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.

  13. Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability.

    Directory of Open Access Journals (Sweden)

    Haoqiang Zhang

    Full Text Available 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, root morphological characters, root tensile force and tensile strength, and parameters for soil aggregate stability at twelve weeks after inoculation. AM fungi colonized more than 70% plant root, significantly improved plant growth. Meanwhile, AM fungi elevated root morphological parameters, root tensile force, root tensile strength, Glomalin-related soil protein (GRSP content in soil, and parameters for soil aggregate stability such as water stable aggregate (WSA, mean weight diameter (MWD and geometric mean diameter (GMD. Root length was highly correlated with WSA, MWD and GMD, while hyphae length was highly correlated with GRSP content. The improved R. pseudoacacia growth, root tensile strength and soil aggregate stability indicated that AM fungi could accelerate soil fixation and stabilization with R. pseudoacacia, and its function in revegetation on Loess Plateau deserves more attention.

  14. 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.

  15. Can arbuscular mycorrhizal fungi improve grain yield, As uptake and tolerance of rice grown under aerobic conditions?

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (Hong Kong); Ye, Z.H. [State Key Laboratory for Bio-control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Chan, W.F.; Chen, X.W.; Wu, F.Y. [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (Hong Kong); Wu, S.C. [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (Hong Kong); School of Environment and Natural Resources, Zhejiang Agriculture and Forestry University, Lin' an, Zhejiang 311300 (China); Wong, M.H., E-mail: mhwong@hkbu.edu.hk [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (Hong Kong); School of Environment and Natural Resources, Zhejiang Agriculture and Forestry University, Lin' an, Zhejiang 311300 (China)

    2011-10-15

    The effects of arbuscular mycorrhizal fungi (AMF) -Glomus intraradices and G. geosporum on arsenic (As) and phosphorus (P) uptake by lowland (Guangyinzhan) and upland rice (Handao 502) were investigated in soil, spiked with and without 60 mg As kg{sup -1}. In As-contaminated soil, Guangyinzhan inoculated with G. intraradices or Handao 502 inoculated with G. geosporum enhanced As tolerance, grain P content, grain yield. However, Guangyinzhan inoculated with G. geosporum or Handao 502 inoculated with G. intraradices decreased grain P content, grain yield and the molar ratio of grain P/As content, and increased the As concentration and the ratio of grain/straw As concentration. These results show that rice/AMF combinations had significant (p < 0.05) effects on grain As concentration, grain yield and grain P uptake. The variation in the transfer and uptake of As and P reflected strong functional diversity in AM (arbuscular mycorrhizal) symbioses. - Highlights: > Rice/AMF combinations had significant effects on grain As concentration, grain yield and grain P uptake. > Rice colonized with suitable AMF can increase grain yield. > The variation in the transfer and uptake of As and P reflected strong functional diversity in AM symbioses. - Different rice/AMF combinations had very different effects on arsenic and phosphorus uptake.

  16. Community Analysis of Arbuscular Mycorrhizal Fungi in Roots of Poncirus trifoliata and Citrus reticulata Based on SSU rDNA

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2014-01-01

    Full Text Available Morphological observation of arbuscular mycorrhizal fungi (AMF species in rhizospheric soil could not accurately reflect the actual AMF colonizing status in roots, while molecular identification of indigenous AMF colonizing citrus rootstocks at present was rare in China. In our study, community of AMF colonizing trifoliate orange (Poncirus trifoliata L. Raf. and red tangerine (Citrus reticulata Blanco were analyzed based on small subunit of ribosomal DNA genes. Morphological observation showed that arbuscular mycorrhizal (AM colonization, spore density, and hyphal length did not differ significantly between two rootstocks. Phylogenetic analysis showed that 173 screened AMF sequences clustered in at least 10 discrete groups (GLO1~GLO10, all belonging to the genus of Glomus Sensu Lato. Among them, GLO1 clade (clustering with uncultured Glomus accounting for 54.43% clones was the most common in trifoliate orange roots, while GLO6 clade (clustering with Glomus intraradices accounting for 35.00% clones was the most common in red tangerine roots. Although, Shannon-Wiener indices exhibited no notable differences between both rootstocks, relative proportions of observed clades analysis revealed that composition of AMF communities colonizing two rootstocks varied severely. The results indicated that native AMF species in citrus rhizosphere had diverse colonization potential between two different rootstocks in the present orchards.

  17. Arbuscular mycorrhizal symbiosis elicits shoot proteome changes that are modified during cadmium stress alleviation in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Gianinazzi-Pearson Vivienne

    2011-05-01

    Full Text Available Abstract Background Arbuscular mycorrhizal (AM fungi, which engage a mutualistic symbiosis with the roots of most plant species, have received much attention for their ability to alleviate heavy metal stress in plants, including cadmium (Cd. While the molecular bases of Cd tolerance displayed by mycorrhizal plants have been extensively analysed in roots, very little is known regarding the mechanisms by which legume aboveground organs can escape metal toxicity upon AM symbiosis. As a model system to address this question, we used Glomus irregulare-colonised Medicago truncatula plants, which were previously shown to accumulate and tolerate heavy metal in their shoots when grown in a substrate spiked with 2 mg Cd kg-1. Results The measurement of three indicators for metal phytoextraction showed that shoots of mycorrhizal M. truncatula plants have a capacity for extracting Cd that is not related to an increase in root-to-shoot translocation rate, but to a high level of allocation plasticity. When analysing the photosynthetic performance in metal-treated mycorrhizal plants relative to those only Cd-supplied, it turned out that the presence of G. irregulare partially alleviated the negative effects of Cd on photosynthesis. To test the mechanisms by which shoots of Cd-treated mycorrhizal plants avoid metal toxicity, we performed a 2-DE/MALDI/TOF-based comparative proteomic analysis of the M. truncatula shoot responses upon mycorrhization and Cd exposure. Whereas the metal-responsive shoot proteins currently identified in non-mycorrhizal M. truncatula indicated that Cd impaired CO2 assimilation, the mycorrhiza-responsive shoot proteome was characterised by an increase in photosynthesis-related proteins coupled to a reduction in glugoneogenesis/glycolysis and antioxidant processes. By contrast, Cd was found to trigger the opposite response coupled the up-accumulation of molecular chaperones in shoot of mycorrhizal plants relative to those metal

  18. Changes in arbuscular mycorrhizal associations and fine root traits in sites under different plant successional phases in southern Brazil.

    Science.gov (United States)

    Zangaro, Waldemar; de Assis, Rafael Leandro; Rostirola, Leila Vergal; de Souza, Priscila Bochi; Gonçalves, Melissa Camargo; Andrade, Galdino; Nogueira, Marco Antonio

    2008-12-01

    Fine root morphological traits and distribution, arbuscular mycorrhizal (AM) fungi, soil fertility, and nutrient concentration in fine root tissue were compared in sites under different successional phases: grass plants, secondary forest, and mature forest in Londrina county, Paraná state, southern Brazil. Soil cores were collected randomly at the 0-10- and 10-20-cm depths in three quadrants (50 m2) in each site. Plants from the different successional stages displayed high differences in fine root distribution, fine root traits, and mycorrhizal root colonization. There were increases in the concentration of nutrients both in soil and fine roots and decrease of bulk soil density along the succession. The fine root biomass and diameter increased with the succession progress. The total fine root length, specific root length, root hair length, and root hair incidence decreased with the succession advance. Similarly, the mycorrhizal root colonization and the density of AM fungi spores in the soil decreased along the succession. Mycorrhizal root colonization and spore density were positively correlated with fine root length, specific root length, root hair length, root hair incidence, and bulk density and negatively correlated with fine root diameter and concentration of some nutrients both in soil and root tissues. Nutrient concentration in root tissue and in soil was positively correlated with fine root diameter and negatively correlated with specific root length, root hair length, and root hair incidence. These results suggest different adaptation strategies of plant roots for soil exploration and mineral acquisition among the different successional stages. Early successional stages displayed plants with fine root morphology and AM fungi colonization to improve the root functional efficiencies for uptake of nutrients and faster soil resource exploration. Late successional stages displayed plants with fine root morphology and mycorrhizal symbiosis for both a lower

  19. Preservation at ultra-low temperature of in vitro cultured arbuscular mycorrhizal fungi via encapsulation-drying.

    Science.gov (United States)

    Lalaymia, Ismahen; Cranenbrouck, Sylvie; Draye, Xavier; Declerck, Stéphane

    2012-10-01

    At present, over 300 species of arbuscular mycorrhizal fungi (AMF) have been identified, most of which being stored in international collections. Their maintenance is mostly achieved in greenhouse via continuous culture on trap plants or in vitro in association with excised root organs. Both methods are work-intensive and for the former present the risk of unwanted contaminations. The in vitro root organ culture of AMF has become an alternative preventing contamination. Nevertheless, the risk for somaclonal variation during the sub-cultivation process cannot be excluded. A method for the long-term conservation that guarantees the stability of the biological material is thus highly demanded to preserve the microorganisms and their genetic stability. Here, 12 AMF isolates cultured in vitro in association with excised carrot roots were encapsulated in alginate beads and subsequently cryopreserved. Several protocols were tested taking into consideration culture age, alginate bead pre-drying, and rate of decrease in temperature. The viability of the AMF isolates was estimated by the percentage of potentially infective beads (%PIB) that measure the % of beads that contain at least one germinated propagule. Thermal behaviour of alginate beads was analysed by a differential thermal calorimeter before and after drying to estimate the frozen and unfrozen water during the cryopreservation process. It was shown that the spore damage was directly related to ice formation during cryopreservation. The encapsulation and culture age were also determinant parameters for the successful cryopreservation. Irrespective of the AMF isolate, the optimal procedure for cryopreservation comprised five steps: (1) the encapsulation of propagules (i.e. spores and mycorrhizal root pieces) isolated from 5m old cultures, (2) the incubation overnight in trehalose (0.5M), (3) the drying during 48h at 27°C, (4) the cryopreservation in the freezer at -130°C following a two-step decrease in

  20. Suppression of the biocontrol agent trichoderma harzianum by mycelium of the arbuscular mycorrhizal fungus glomus intraradices in root-free soil

    Science.gov (United States)

    Green; Larsen; Olsson; Jensen; Jakobsen

    1999-04-01

    Trichoderma harzianum is an effective biocontrol agent against several fungal soilborne plant pathogens. However, possible adverse effects of this fungus on arbuscular mycorrhizal fungi might be a drawback in its use in plant protection. The objective of the present work was to examine the interaction between Glomus intraradices and T. harzianum in soil. The use of a compartmented growth system with root-free soil compartments enabled us to study fungal interactions without the interfering effects of roots. Growth of the fungi was monitored by measuring hyphal length and population densities, while specific fatty acid signatures were used as indicators of living fungal biomass. Hyphal 33P transport and beta-glucuronidase (GUS) activity were used to monitor activity of G. intraradices and a GUS-transformed strain of T. harzianum, respectively. As growth and metabolism of T. harzianum are requirements for antagonism, the impact of wheat bran, added as an organic nutrient source for T. harzianum, was investigated. The presence of T. harzianum in root-free soil reduced root colonization by G. intraradices. The external hyphal length density of G. intraradices was reduced by the presence of T. harzianum in combination with wheat bran, but the living hyphal biomass, measured as the content of a membrane fatty acid, was not reduced. Hyphal 33P transport by G. intraradices also was not affected by T. harzianum. This suggests that T. harzianum exploited the dead mycelium but not the living biomass of G. intraradices. The presence of external mycelium of G. intraradices suppressed T. harzianum population development and GUS activity. Stimulation of the hyphal biomass of G. intraradices by organic amendment suggests that nutrient competition is a likely means of interaction. In conclusion, it seemed that growth of and phosphorus uptake by the external mycelium of G. intraradices were not affected by the antagonistic fungus T. harzianum; in contrast, T. harzianum was adversely

  1. Modelling Spatial Interactions in the Arbuscular Mycorrhizal Symbiosis using the Calculus of Wrapped Compartments

    Directory of Open Access Journals (Sweden)

    Cristina Calcagno

    2011-09-01

    Full Text Available Arbuscular mycorrhiza (AM is the most wide-spread plant-fungus symbiosis on earth. Investigating this kind of symbiosis is considered one of the most promising ways to develop methods to nurture plants in more natural manners, avoiding the complex chemical productions used nowadays to produce artificial fertilizers. In previous work we used the Calculus of Wrapped Compartments (CWC to investigate different phases of the AM symbiosis. In this paper, we continue this line of research by modelling the colonisation of the plant root cells by the fungal hyphae spreading in the soil. This study requires the description of some spatial interaction. Although CWC has no explicit feature modelling a spatial geometry, the compartment labelling feature can be effectively exploited to define a discrete surface topology outlining the relevant sectors which determine the spatial properties of the system under consideration. Different situations and interesting spatial properties can be modelled and analysed in such a lightweight framework (which has not an explicit notion of geometry with coordinates and spatial metrics, thus exploiting the existing CWC simulation tool.

  2. Phylogeny of the glomeromycota (arbuscular mycorrhizal fungi): recent developments and new gene markers.

    Science.gov (United States)

    Redecker, Dirk; Raab, Philipp

    2006-01-01

    The fungal symbionts of arbuscular mycorrhiza form a monophyletic group in the true Fungi, the phylum Glomeromycota. Fewer than 200 described species currently are included in this group. The only member of this clade known to form a different type of symbiosis is Geosiphon pyriformis, which associates with cyanobacteria. Because none of these fungi has been cultivated without their plant hosts or cyanobacterial partners, progress in obtaining multigene phylogenies has been slow and the nuclear-encoded ribosomal RNA genes have remained the only widely accessible molecular markers. rDNA phylogenies have revealed considerable polyphyly of some glomeromycotan genera that has been used to reassess taxonomic concepts. Environmental studies using phylogenetic methods for molecular identification have recovered an amazing diversity of unknown phylotypes, suggesting considerable cryptic species diversity. Protein gene sequences that have become available recently have challenged the rDNA-supported sister group relationship of the Glomeromycota with Asco/Basidiomycota. However the number of taxa analyzed with these new markers is still too small to provide a comprehensive picture of intraphylum relationships. We use nuclear-encoded rDNA and rpb1 protein gene sequences to reassess the phylogeny of the Glomeromycota and discuss possible implications.

  3. Full establishment of arbuscular mycorrhizal symbiosis in rice occurs independently of enzymatic jasmonate biosynthesis.

    Directory of Open Access Journals (Sweden)

    Caroline Gutjahr

    Full Text Available Development of the mutualistic arbuscular mycorrhiza (AM symbiosis between most land plants and fungi of the Glomeromycota is regulated by phytohormones. The role of jasmonate (JA in AM colonization has been investigated in the dicotyledons Medicago truncatula, tomato and Nicotiana attenuata and contradicting results have been obtained with respect to a neutral, promotive or inhibitory effect of JA on AM colonization. Furthermore, it is currently unknown whether JA plays a role in AM colonization of monocotyledonous roots. Therefore we examined whether JA biosynthesis is required for AM colonization of the monocot rice. To this end we employed the rice mutant constitutive photomorphogenesis 2 (cpm2, which is deficient in JA biosynthesis. Through a time course experiment the amount and morphology of fungal colonization did not differ between wild-type and cpm2 roots. Furthermore, no significant difference in the expression of AM marker genes was detected between wild type and cpm2. However, treatment of wild-type roots with 50 μM JA lead to a decrease of AM colonization and this was correlated with induction of the defense gene PR4. These results indicate that JA is not required for AM colonization of rice but high levels of JA in the roots suppress AM development likely through the induction of defense.

  4. Application of arbuscular mycorrhizal fungi on the production of cut flower roses under commercial-like conditions

    Energy Technology Data Exchange (ETDEWEB)

    Garmendia, I.; Mangas, V. J.

    2012-11-01

    The objective of this work was to study the influence of two arbuscular mycorrhizal fungi (AMF) Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and G. intraradices (Schenck and Smith) on cut flower yield of rose (Rosa hybrida L. cv. Grand Gala) under commercial-like greenhouse conditions. Flower production was positively influenced by G. mosseae inoculation. Both inocula tested caused low levels of mycorrhizal root colonization, with higher percentages in Rosa associated with G. mosseae. Significant improvement of plant biomass, leaf nutritional status or flower quality was not detected in inoculated plants probably due to the low symbiosis establishment. However, G. mosseae reduced by one month the time needed for 80% of the plants to flower and slightly increased number of cut flowers relative to non-mycorrhizal controls on the fourth, sixth and eighth months after transplanting. It is suggested that an altered carbohydrate metabolism could contribute to this positive effect. Low colonization of rose roots supports the idea that more effort is required to ensure successful application of AMF in ornamental production systems. (Author) 40 refs.

  5. Effect of arbuscular mycorrhizal colonization and two levels of compost supply on nutrient uptake and flowering of pelargonium plants.

    Science.gov (United States)

    Perner, Henrike; Schwarz, Dietmar; Bruns, Christian; Mäder, Paul; George, Eckhard

    2007-07-01

    Two challenges frequently encountered in the production of ornamental plants in organic horticulture are: (1) the rate of mineralization of phosphorus (P) and nitrogen (N) from organic fertilizers can be too slow to meet the high nutrient demand of young plants, and (2) the exclusive use of peat as a substrate for pot-based plant culture is discouraged in organic production systems. In this situation, the use of beneficial soil microorganisms in combination with high quality compost substrates can contribute to adequate plant growth and flower development. In this study, we examined possible alternatives to highly soluble fertilizers and pure peat substrates using pelargonium (Pelargonium peltatum L'Her.) as a test plant. Plants were grown on a peat-based substrate with two rates of compost addition and with and without arbuscular mycorrhizal (AM) fungi. Inoculation with three different commercial AM inocula resulted in colonization rates of up to 36% of the total root length, whereas non-inoculated plants remained free of root colonization. Increasing the rate of compost addition increased shoot dry weight and shoot nutrient concentrations, but the supply of compost did not always completely meet plant nutrient demand. Mycorrhizal colonization increased the number of buds and flowers, as well as shoot P and potassium (K) concentrations, but did not significantly affect shoot dry matter or shoot N concentration. We conclude that addition of compost in combination with mycorrhizal inoculation can improve nutrient status and flower development of plants grown on peat-based substrates.

  6. The impact of arbuscular mycorrhizal fungi in mitigating salt-induced adverse effects in sweet basil (Ocimum basilicum L.

    Directory of Open Access Journals (Sweden)

    Khalid M. Elhindi

    2017-01-01

    Full Text Available Salinity is one of the serious abiotic stresses adversely affecting the majority of arable lands worldwide, limiting the crop productivity of most of the economically important crops. Sweet basil (Osmium basilicum plants were grown in a non-saline soil (EC = 0.64 dS m−1, in low saline soil (EC = 5 dS m−1, and in a high saline soil (EC = 10 dS m−1. There were differences between arbuscular mycorrhizal (Glomus deserticola colonized plants (+AMF and non-colonized plants (−AMF. Mycorrhiza mitigated the reduction of K, P and Ca uptake due to salinity. The balance between K/Na and between Ca/Na was improved in +AMF plants. Growth enhancement by mycorrhiza was independent from plant phosphorus content under high salinity levels. Different growth parameters, salt stress tolerance and accumulation of proline content were investigated, these results showed that the use of mycorrhizal inoculum (AMF was able to enhance the productivity of sweet basil plants under salinity conditions. Mycorrhizal inoculation significantly increased chlorophyll content and water use efficiency under salinity stress. The sweet basil plants appeared to have high dependency on AMF which improved plant growth, photosynthetic efficiency, gas exchange and water use efficiency under salinity stress. In this study, there was evidence that colonization with AMF can alleviate the detrimental salinity stress influence on the growth and productivity of sweet basil plants.

  7. Arbuscular mycorrhizal fungi contribute to phosphorus uptake by wheat grown in a phosphorus-fixing soil even in the absence of positive growth responses.

    Science.gov (United States)

    Li, Huiying; Smith, Sally E; Holloway, Robert E; Zhu, Yongguan; Smith, F Andrew

    2006-01-01

    We used 32P to quantify the contribution of an arbuscular mycorrhizal (AM) fungus (Glomus intraradices) to phosphorus (P) uptake by wheat (Triticum aestivum), grown in compartmented pots. The soil was from a major cereal-growing area, the Eyre Peninsula, South Australia; it was highly calcareous and P-fixing. Fertilizer P was added to soil at 20 mg kg(-1), as solid or liquid. Two extraction methods were used to estimate plant-available P. Fungal colonization was well established at harvest (36 d). Application of P decreased both colonization and hyphal length density in soil, with small differences between different P fertilizers. Plants showed large positive responses in terms of growth or total P uptake to all P additions, and showed no positive (or even negative) responses to AM colonization, regardless of P application. 32P was detected only in AM plants, and we calculated that over 50% of P uptake by plants was absorbed via AM fungi, even when P was added. The results add to the growing body of knowledge that 'nonresponsive' AM plants have a functional AM pathway for P transfer to the plant; it should not be ignored in breeding plants for root traits designed to improve P uptake.

  8. Dry matter and root colonization of plants by indigenous arbuscular mycorrhizal fungi with physical fractions of dry olive mill residue inoculated with saprophytic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, E.; Sampredro, I.; Diaz, R.; Garcia-Sanchez, M.; Siles, J. A.; Ocampo, J. A.; Garcia-Romera, I.

    2010-07-01

    We studied the influence of indigenous arbuscular mycorrhizal (AM) and saprobe fungi on the phytotoxicity of the physical fractions of dry olive mill residue (DOR). The physical extractions of DOR gave an aqueous (ADOR) and an exhausted (SDOR) fraction with less phytotoxicity for tomato than the original samples. The indigenous AM were able to decrease the phytotoxicity of SDOR inoculated with Trametes versicolor and Pycnoporus cinnabarinus on tomato. However, incubation of ADOR with both saprophytic fungi did not decrease its phytotoxicity in presence of the indigenous AM fungi. The percentage of root length colonized by indigenous AM strongly decreased in presence of DOR, around 80% of decrease at dose of 25 g kg-1of DOR, but the level of mycorrhization was higher in presence of ADOR or SDOR (38% and 44% of decrease respectively at the same dose). There were no relationships between the effects of the physical fractions of DOR incubated with the saprobe fungi on AM colonization and on plant dry weight of tomato. Our results suggest that the phytotoxicity of the olive residues can be eliminated by the combination of physical extraction and by saprobe fungal inoculation and the use of this agrowaste as organic amendment in agricultural soil may be possible. (Author) 33 refs.

  9. The largest subunit of RNA polymerase II as a new marker gene to study assemblages of arbuscular mycorrhizal fungi in the field.

    Directory of Open Access Journals (Sweden)

    Herbert Stockinger

    Full Text Available Due to the potential of arbuscular mycorrhizal fungi (AMF, Glomeromycota to improve plant growth and soil quality, the influence of agricultural practice on their diversity continues to be an important research question. Up to now studies of community diversity in AMF have exclusively been based on nuclear ribosomal gene regions, which in AMF show high intra-organism polymorphism, seriously complicating interpretation of these data. We designed specific PCR primers for 454 sequencing of a region of the largest subunit of RNA polymerase II gene, and established a new reference dataset comprising all major AMF lineages. This gene is known to be monomorphic within fungal isolates but shows an excellent barcode gap between species. We designed a primer set to amplify all known lineages of AMF and demonstrated its applicability in combination with high-throughput sequencing in a long-term tillage experiment. The PCR primers showed a specificity of 99.94% for glomeromycotan sequences. We found evidence of significant shifts of the AMF communities caused by soil management and showed that tillage effects on different AMF taxa are clearly more complex than previously thought. The high resolving power of high-throughput sequencing highlights the need for quantitative measurements to efficiently detect these effects.

  10. Genetic Exchange in an Arbuscular Mycorrhizal Fungus Results in Increased Rice Growth and Altered Mycorrhiza-Specific Gene Transcription▿†

    Science.gov (United States)

    Colard, Alexandre; Angelard, Caroline; Sanders, Ian R.

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate symbionts with most terrestrial plants. They improve plant nutrition, particularly phosphate acquisition, and thus are able to improve plant growth. In exchange, the fungi obtain photosynthetically fixed carbon. AMF are coenocytic, meaning that many nuclei coexist in a common cytoplasm. Genetic exchange recently has been demonstrated in the AMF Glomus intraradices, allowing nuclei of different Glomus intraradices strains to mix. Such genetic exchange was shown previously to have negative effects on plant growth and to alter fungal colonization. However, no attempt was made to detect whether genetic exchange in AMF can alter plant gene expression and if this effect was time dependent. Here, we show that genetic exchange in AMF also can be beneficial for rice growth, and that symbiosis-specific gene transcription is altered by genetic exchange. Moreover, our results show that genetic exchange can change the dynamics of the colonization of the fungus in the plant. Our results demonstrate that the simple manipulation of the genetics of AMF can have important consequences for their symbiotic effects on plants such as rice, which is considered the most important crop in the world. Exploiting natural AMF genetic variation by generating novel AMF genotypes through genetic exchange is a potentially useful tool in the development of AMF inocula that are more beneficial for crop growth. PMID:21784911

  11. Influence of habitat and climate variables on arbuscular mycorrhizal fungus community distribution, as revealed by a case study of facultative plant epiphytism under semiarid conditions.

    Science.gov (United States)

    Torrecillas, E; Torres, P; Alguacil, M M; Querejeta, J I; Roldán, A

    2013-12-01

    In semiarid Mediterranean ecosystems, epiphytic plant species are practically absent, and only some species of palm trees can support epiphytes growing in their lower crown area, such as Phoenix dactylifera L. (date palm). In this study, we focused on Sonchus tenerrimus L. plants growing as facultative epiphytes in P. dactylifera and its terrestrial forms growing in adjacent soils. Our aim was to determine the possible presence of arbuscular mycorrhizal fungi (AMF) in these peculiar habitats and to relate AMF communities with climatic variations. We investigated the AMF community composition of epiphytic and terrestrial S. tenerrimus plants along a temperature and precipitation gradient across 12 localities. Epiphytic roots were colonized by AMF, as determined by microscopic observation; all of the epiphytic and terrestrial samples analyzed showed AMF sequences from taxa belonging to the phylum Glomeromycota, which were grouped in 30 AMF operational taxonomic units. The AMF community composition was clearly different between epiphytic and terrestrial root samples, and this could be attributable to dispersal constraints and/or the contrasting environmental and ecophysiological conditions prevailing in each habitat. Across sites, the richness and diversity of terrestrial AMF communities was positively correlated with rainfall amount during the most recent growing season. In contrast, there was no significant correlation between climate variables and AMF richness and diversity for epiphytic AMF communities, which suggests that the composition of AMF communities in epiphytic habitats appears to be largely determined by the availability and dispersion of fungal propagules from adjacent terrestrial habitats.

  12. Trypan blue as a fluorochrome for confocal laser scanning microscopy of arbuscular mycorrhizae in three mangroves.

    Science.gov (United States)

    Kumar, T; Majumdar, A; Das, P; Sarafis, V; Ghose, M

    2008-06-01

    Roots of three mangroves, Acanthus ilicifolius, Ceriops tagal and Excoecaria agallocha, collected from forests of the Sundarbans of India were stained with trypan blue to observe arbuscular mycorrhizal colonization. Spores of arbuscular mycorrhizal fungi isolated from rhizospheric soil, collected together with the root samples, also were stained for testing the suitability of the dye as a fluorochrome. Confocal laser scanning microscopy images were constructed. A. ilicifolius and E. agallocha exhibited "Arum" type colonization with highly branched arbuscules, whereas C. tagal showed "Paris" type association with clumped and collapsed arbuscules. We demonstrated that trypan blue is a suitable fluorochrome for staining arbuscular mycorrhizal fungal spores, fungal hyphae, arbuscules and vesicles, which presumably have a considerable amount of surface chitin. It appears that as the integration of chitin into the fungal cell wall changes, its accessibility to trypan blue dye also changes.

  13. Infectivity of Arbuscular Mycorrhizal Fungi in Naturally Regenerating, Unmanaged and Clear-Cut Beech Forests

    Institute of Scientific and Technical Information of China (English)

    I.CLOSA; N.GOICOECHEA

    2011-01-01

    Clear-cutting, a management practice applied to many beech forests in the North of Spain, modifies microclimate and, consequently,the composition of the understory plant community in the disturbed areas. The objectives of this study were to assess if changes in the understory vegetation caused by altered light microclimate after clear-cutting affect the infectivity of arbuscular mycorrhizal fungi (AMF) on herbaceous plant species in beech (Fagus sylvatica L.) forests naturally regenerating from clear-cutting and to test if the use of bioassays for studying the infectivity of native AMF could provide aseful information to improve the management of clear-cut areas.Three nearby beech forests in northwest Navarra, Spain, a region in the northwest part of the Pyrenees, were selected: an unmanaged forest, a forest clear-cut in 1996, and another forest clear-cut in 2001. High stem density in the forest clear-cut in 1996 (44 000 trees ha-1) attenuated photosynthetic active radiation (PAR) and impaired the growth of herbaceous species within the ecosystem. The percentage of AMF colonization of plants in bioassays performed on soil samples collected from the forest clear-cut in 1996 was always lower than 10%. In the forest clear-cut in 2001, where soil was covered by perennial grasses, PAR was high and thc infectivity of native AMF achieved minimum values in spring and autumn and a maximum value in summer. In contrast, the infectivity of native AMF in the umnanaged forest remained similar across the seasons. Our results demonstrated that changes in the composition of understory vegetation within beech forests strongly affected the infectivity of native AMF in clear-cut areas and suggested that the assessment of the infectivity of native AMF through bioassays could provide helpful information for planning either the removal of overstory when the tree density is so high that it impairs the correct development of herbaceous species or the plantation of new sesdlings when high

  14. Effect of arbuscular mycorrhizal fungi and vermicompost liquid extract on quality of straberry

    Directory of Open Access Journals (Sweden)

    Fabián Heriberto Rivera Chávez

    2012-09-01

    Full Text Available The application of arbuscular mycorrhizal fungi (AMF and vermicompost is one of the alternatives to agrochemical products, to reach crops yield and quality, reducing costs and environmental damage. In the present study, the effect of applying AMF and vermicompost aquose extract (LV on strawberry fruit quality, was evaluated. The treatments were: 1control with water (CTL; 2 fertilized (F; 3 inoculated with AMF (M; 4 with vermicompost aquose extract (LV; 5inoculated with AMF and fertilized (M+F; 6 fertilized and with vermicompost aquose extract (LV+F; 7 inoculatedwith AMF, and treated with vermicompost aquose extract (M+LV; 8 inoculated with AMF, fertilized and treated with vermicompost aquose extract (M+F+LV. The evaluated parameters were: color, weight, polar and equatorial diameter, firmness, ºBrix, proximal analysis, phenols, flavonoids and anthocyanins contents. LV and M treatments promoted asignificant increase of fruit weight (39% compared to the fertilized treatment. In general, treatments with AMF increased ash except when combined with fertilization. The M treatment caused a significant increase of ash (3.7% respect to the F treatment. The treatments containing AMF and LV (alone or combined with others increased fat content in fruits, in comparison with the F treatment. There were no significant effects treatments on fiber content. Fruits from plants treated with LV+F were significantly firmer (20% than fruits in the F treatment. Fruits in the M+F treatment showed the higher values of °Brix (14% higher than fruits in the F treatment. Interestingly, fruits from the treatments LV and M+F had significantly superior contents of total phenols than fruits from the F treatment (29 and 17% respectively. In general, the treatments containing AMF and LV promoted flavonoides accumulations in fruits. Fruits of the M treatment showed a significantly greater content of this pigments (1.8 times than fruits of the F treatment. Fruits of the M

  15. Desempenho de fungos micorrízicos arbusculares na produção de mudas de maracujazeiro-amarelo, em diferentes substratos Arbuscular mycorrhizal fungi performance to produce mycorrhizal passionflower seedlings under different substrates

    Directory of Open Access Journals (Sweden)

    Adriana Parada Dias da Silveira

    2003-01-01

    Full Text Available O trabalho teve por objetivo selecionar fungos micorrízicos arbusculares (FMAs eficientes na promoção do crescimento de mudas de maracujazeiro-amarelo, em substrato esterilizado, com diferentes níveis de fertilidade, em função da adição ou não de matéria orgânica. Foram realizados três experimentos, em casa de vegetação. No primeiro, empregou-se como substrato uma mistura de 2:1:1 de areia, solo (Latossolo Vermelho Eutroférrico e esterco de curral; no segundo, uma mistura de 1:1 de solo e areia e no terceiro, uma mistura de 9:1 de solo e esterco de curral. Os FMAs empregados foram: Acaulospora sp.(IAC-13, Gigaspora margarita, Glomus sp (IAC-27, Acaulospora morrowae, Acaulospora sp. (IAC-44, Acaulospora scrobiculata, Scutellospora heterogama, Glomus clarum,Glomus sp. (IAC-28, Entrophospora colombiana, Glomus etunicatum e Glomus macrocarpum. No terceiro experimento, empregaram-se G. clarum, Glomus sp. (IAC-28, G. margarita, G. etunicatum e G. macrocarpum (IAC-50, uma mistura dessas espécies e populações de fungos nativos, oriundas de solo de uma cultura de maracujá estabelecida no campo e multiplicadas em Brachiaria decumbens, maracujazeiro e amendoinzeiro. Os efeitos positivos da micorrização foram maiores no substrato sem adição de matéria orgânica (esterco de curral, não superando, entretanto, o efeito da sua adição. G. clarum, G. etunicatum e G. margarita promoveram aumento significativo na produção de matéria seca. No substrato com adição de 25% de matéria orgânica, os fungos Acaulospora sp. (IAC- 44 e A. morrowae foram eficientes na promoção do desenvolvimento das mudas, com desempenho comparável ao Glomus sp. (IAC- 28 no substrato com adição de 10% de esterco de curral. G. clarum mostrou efeito parasítico, diminuindo o crescimento das plantas no substrato com 25% de matéria orgânica.The purpose of this study was to select effective arbuscular mycorrhizal fungi (AMF on the production of yellow

  16. The Comparison of Expressed Candidate Secreted Proteins from Two Arbuscular Mycorrhizal Fungi Unravels Common and Specific Molecular Tools to Invade Different Host Plants

    Science.gov (United States)

    Kamel, Laurent; Tang, Nianwu; Malbreil, Mathilde; San Clemente, Hélène; Le Marquer, Morgane; Roux, Christophe; Frei dit Frey, Nicolas

    2017-01-01

    Arbuscular mycorrhizal fungi (AMF), belonging to the fungal phylum Glomeromycota, form mutualistic symbioses with roots of almost 80% of land plants. The release of genomic data from the ubiquitous AMF Rhizophagus irregularis revealed that this species possesses a large set of putative secreted proteins (RiSPs) that could be of major importance for establishing the symbiosis. In the present study, we aimed to identify SPs involved in the establishment of AM symbiosis based on comparative gene expression analyses. We first curated the secretome of the R. irregularis DAOM 197198 strain based on two available genomic assemblies. Then we analyzed the expression patterns of the putative RiSPs obtained from the fungus in symbiotic association with three phylogenetically distant host plants—a monocot, a dicot and a liverwort—in comparison with non-symbiotic stages. We found that 33 out of 84 RiSPs induced in planta were commonly up-regulated in these three hosts. Most of these common RiSPs are small proteins of unknown function that may represent putative host non-specific effector proteins. We further investigated the expressed secretome of Gigaspora rosea, an AM fungal species phylogenetically distant from R. irregularis. G. rosea also presents original symbiotic features, a narrower host spectrum and a restrictive geographic distribution compared to R. irregularis. Interestingly, when analyzing up-regulated G. rosea SPs (GrSPs) in different hosts, a higher ratio of host-specific GrSPs was found compared to RiSPs. Such difference of expression patterns may mirror the restrained host spectrum of G. rosea compared to R. irregularis. Finally, we identified a set of conserved SPs, commonly up-regulated by both fungi in all hosts tested, that could correspond to common keys of AMF to colonize host plants. Our data thus highlight the specificities of two distant AM fungi and help in understanding their conserved and specific strategies to invade different hosts.

  17. Jatropha curcas and Ricinus communis differentially affect arbuscular mycorrhizal fungi diversity in soil when cultivated for biofuel production in a Guantanamo (Cuba) tropical system.

    Science.gov (United States)

    Alguacil, M. M.; Torrecillas, E.; Hernández, G.; Torres, P.; Roldán, A.

    2012-04-01

    The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a control soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity) were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare) disappeared in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C) were improved by the cultivation of the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the control soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable in long-term conservation and sustainable management of these tropical ecosystems.

  18. Effect of arbuscular mycorrhizal fungi on plant biomass and the rhizosphere microbial community structure of mesquite grown in acidic lead/zinc mine tailings.

    Science.gov (United States)

    Solís-Domínguez, Fernando A; Valentín-Vargas, Alexis; Chorover, Jon; Maier, Raina M

    2011-02-15

    Mine tailings in arid and semi-arid environments are barren of vegetation and subject to eolian dispersion and water erosion. Revegetation is a cost-effective strategy to reduce erosion processes and has wide public acceptance. A major cost of revegetation is the addition of amendments, such as compost, to allow plant establishment. In this paper we explore whether arbuscular mycorrhizal fungi (AMF) can help support plant growth in tailings at a reduced compost concentration. A greenhouse experiment was performed to determine the effects of three AMF inocula on biomass, shoot accumulation of heavy metals, and changes in the rhizosphere microbial community structure of the native plant Prosopis juliflora (mesquite). Plants were grown in an acidic lead/zinc mine tailings amended with 10% (w/w) compost amendment, which is slightly sub-optimal for plant growth in these tailings. After two months, AMF-inoculated plants showed increased dry biomass and root length (p<0.05) and effective AMF colonization compared to controls grown in uninoculated compost-amended tailings. Mesquite shoot tissue lead and zinc concentrations did not exceed domestic animal toxicity limits regardless of whether AMF inoculation was used. The rhizosphere microbial community structure was assessed using denaturing gradient gel electrophoresis (DGGE) profiles of the small subunit RNA gene for bacteria and fungi. Canonical correspondence analysis (CCA) of DGGE profiles showed that the rhizosphere fungal community structure at the end of the experiment was significantly different from the community structure in the tailings, compost, and AMF inocula prior to planting. Further, CCA showed that AMF inoculation significantly influenced the development of both the fungal and bacterial rhizosphere community structures after two months. The changes observed in the rhizosphere microbial community structure may be either a direct effect of the AMF inocula, caused by changes in plant physiology induced by

  19. Arbuscular mycorrhizal fungi in phytoremediation of contaminated areas by trace elements: mechanisms and major benefits of their applications.

    Science.gov (United States)

    Cabral, Lucélia; Soares, Claúdio Roberto Fonsêca Sousa; Giachini, Admir José; Siqueira, José Oswaldo

    2015-11-01

    In recent decades, the concentration of trace elements has increased in soil and water, mainly by industrialization and urbanization. Recovery of contaminated areas is generally complex. In that respect, microorganisms can be of vital importance by making significant contributions towards the establishment of plants and the stabilization of impacted areas. Among the available strategies for environmental recovery, bioremediation and phytoremediation outstand. Arbuscular mycorrhizal fungi (AMF) are considered the most important type of mycorrhizae for phytoremediation. AMF have broad occurrence in contaminated soils, and evidences suggest they improve plant tolerance to excess of certain trace elements. In this review, the use of AMF in phytoremediation and mechanisms involved in their trace element tolerance are discussed. Additionally, we present some techniques used to study the retention of trace elements by AMF, as well as a summary of studies showing major benefits of AMF for phytoremediation.

  20. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes

    DEFF Research Database (Denmark)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai;

    2014-01-01

    The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled...... with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM...... colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde...

  1. 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

  2. Molecular community analysis of arbuscular mycorrhizal fungi in roots of geothermal soils in Yellowstone National Park (USA).

    Science.gov (United States)

    Appoloni, Susann; Lekberg, Ylva; Tercek, Michael T; Zabinski, Catherine A; Redecker, Dirk

    2008-11-01

    To better understand adaptation of plants and their mycorrhizae to extreme environmental conditions, we analyzed the composition of communities of arbuscular mycorrhizal fungi (AMF) in roots from geothermal sites in Yellowstone National Park (YNP), USA. Arbuscular mycorrhizal fungi were identified using molecular methods including seven specific primer pairs for regions of the ribosomal DNA that amplify different subgroups of AMF. Roots of Dichanthelium lanuginosum, a grass only occurring in geothermal areas, were sampled along with thermal and nonthermal Agrostis scabra and control plants growing outside the thermally influenced sites. In addition, root samples of Agrostis stolonifera from geothermal areas of Iceland were analyzed to identify possible common mycosymbionts between these geographically isolated locations. In YNP, 16 ribosomal DNA phylotypes belonging to the genera Archaeospora, Glomus, Paraglomus, Scutellospora, and Acaulospora were detected. Eight of these phylotypes could be assigned to known morphospecies, two others have been reported previously in molecular studies from different environments, and six were new to science. The most diverse and abundant lineage was Glomus group A, with the most frequent phylotype corresponding to Glomus intraradices. Five of the seven phylotypes detected in a preliminary sampling in a geothermal area in Iceland were also found in YNP. Nonthermal vegetation was dominated by a high diversity of Glomus group A phylotypes while nonthermal plants were not. Using multivariate analyses, a subset of three phylotypes were determined to be associated with geothermal conditions in the field sites analyzed. In conclusion, AMF communities in geothermal soils are distinct in their composition, including both unique phylotypes and generalist fungi that occur across a broad range of environmental conditions.

  3. Interactions between an arbuscular mycorrhizal fungus (Scutellospora heterogama and the root-knot nematode (Meloidogyne incognita on sweet passion fruit (Passiflora alata

    Directory of Open Access Journals (Sweden)

    Érika Cristina Teixeira dos Anjos

    2010-08-01

    Full Text Available The effects of inoculation of sweet passion fruit plants with the arbuscular mycorrhizal (AM fungus Scutellospora heterogama on the symptoms produced by Meloidogyne incognita race 1 and its reproduction were evaluated in two greenhouse experiments. In the 1st, the M. incognita (5000 eggs/plant and S. heterogama (200 spores/plant inoculations were simultaneous; in the 2nd, the nematodes were inoculated 120 days after the fungal inoculation. In both the experiments, 220 days after AM fungal inoculation, plant growth was stimulated by the fungus. In disinfested soil, control seedlings (without S. heterogama were intolerant to parasitism of M. incognita, while the growth of mycorrhized seedlings was not affected. Sporulation of S. heterogama was negatively affected by the nematodes that did not impair the colonization. M. incognita did not affect mycorrhizal seedling growth. The establishment of mycorrhiza prior to the nematode infection contributed for the reduction of symptoms severity and reproduction of M. incognita in disinfested soil.O efeito da inoculação com Scutellospora heterogama (200 esporos/planta em relação aos sintomas e reprodução de Meloidogyne incognita raça 1 (5000 ovos/planta foi avaliado em plantas de maracujazeiro doce em dois experimentos em casa de vegetação. No primeiro experimento, inoculações com nematóide e FMA foram simultâneas; no segundo, nematóides foram inoculados 120 dias após o estabelecimento da simbiose micorrízica. Após o 220º dia da inoculação do FMA o fungo estimulou o crescimento da planta nos dois experimentos. No solo desinfestado as mudas não inoculadas com S. heterogama mostraram intolerância ao parasitismo de M. incognita. A esporulação de S. heterogama foi negativamente afetada pela presença do nematóide. M. incognita não afetou o crescimento das mudas micorrizadas ou o desenvolvimento do FMA. O estabelecimento da micorriza antes do nematóide contribui para a redução da

  4. Molecular diversity of arbuscular mycorrhizal fungi in onion roots from organic and conventional farming systems in the Netherlands.

    Science.gov (United States)

    Galván, Guillermo A; Parádi, István; Burger, Karin; Baar, Jacqueline; Kuyper, Thomas W; Scholten, Olga E; Kik, Chris

    2009-06-01

    Diversity and colonization levels of naturally occurring arbuscular mycorrhizal fungi (AMF) in onion roots were studied to compare organic and conventional farming systems in the Netherlands. In 2004, 20 onion fields were sampled in a balanced survey between farming systems and between two regions, namely, Zeeland and Flevoland. In 2005, nine conventional and ten organic fields were additionally surveyed in Flevoland. AMF phylotypes were identified by rDNA sequencing. All plants were colonized, with 60% for arbuscular colonization and 84% for hyphal colonization as grand means. In Zeeland, onion roots from organic fields had higher fractional colonization levels than those from conventional fields. Onion yields in conventional farming were positively correlated with colonization level. Overall, 14 AMF phylotypes were identified. The number of phylotypes per field ranged from one to six. Two phylotypes associated with the Glomus mosseae-coronatum and the G. caledonium-geosporum species complexes were the most abundant, whereas other phylotypes were infrequently found. Organic and conventional farming systems had similar number of phylotypes per field and Shannon diversity indices. A few organic and conventional fields had larger number of phylotypes, including phylotypes associated with the genera Glomus-B, Archaeospora, and Paraglomus. This suggests that farming systems as such did not influence AMF diversity, but rather specific environmental conditions or agricultural practices.

  5. Evaluation of arbuscular mycorrhizal fungi capacity to alleviate abiotic stress of olive (Olea europaea L.) plants at different transplant conditions.

    Science.gov (United States)

    Bompadre, María Josefina; Pérgola, Mariana; Fernández Bidondo, Laura; Colombo, Roxana Paula; Silvani, Vanesa Analía; Pardo, Alejandro Guillermo; Ocampo, Juan Antonio; Godeas, Alicia Margarita

    2014-01-01

    The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS) in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF). AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5) in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth.

  6. Evaluation of Arbuscular Mycorrhizal Fungi Capacity to Alleviate Abiotic Stress of Olive (Olea europaea L. Plants at Different Transplant Conditions

    Directory of Open Access Journals (Sweden)

    María Josefina Bompadre

    2014-01-01

    Full Text Available The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF. AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5 in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth.

  7. Evaluation of Arbuscular Mycorrhizal Fungi Capacity to Alleviate Abiotic Stress of Olive (Olea europaea L.) Plants at Different Transplant Conditions

    Science.gov (United States)

    Bompadre, María Josefina; Pérgola, Mariana; Fernández Bidondo, Laura; Colombo, Roxana Paula; Silvani, Vanesa Analía; Pardo, Alejandro Guillermo; Ocampo, Juan Antonio; Godeas, Alicia Margarita

    2014-01-01

    The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS) in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF). AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5) in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth. PMID:24688382

  8. Current developments in arbuscular mycorrhizal fungi research and its role in salinity stress alleviation: a biotechnological perspective.

    Science.gov (United States)

    Kumar, Ashwani; Dames, Joanna F; Gupta, Aditi; Sharma, Satyawati; Gilbert, Jack A; Ahmad, Parvaiz

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) form widespread symbiotic associations with 80% of known land plants. They play a major role in plant nutrition, growth, water absorption, nutrient cycling and protection from pathogens, and as a result, contribute to ecosystem processes. Salinity stress conditions undoubtedly limit plant productivity and, therefore, the role of AMF as a biological tool for improving plant salt stress tolerance, is gaining economic importance worldwide. However, this approach requires a better understanding of how plants and AMF intimately interact with each other in saline environments and how this interaction leads to physiological changes in plants. This knowledge is important to develop sustainable strategies for successful utilization of AMF to improve plant health under a variety of stress conditions. Recent advances in the field of molecular biology, "omics" technology and advanced microscopy can provide new insight about these mechanisms of interaction between AMF and plants, as well as other microbes. This review mainly discusses the effect of salinity on AMF and plants, and role of AMF in alleviation of salinity stress including insight on methods for AMF identification. The focus remains on latest advancements in mycorrhizal research that can potentially offer an integrative understanding of the role of AMF in salinity tolerance and sustainable crop production.

  9. Contribution of arbuscular mycorrhizal fungi of sedges to soil aggregation along an altitudinal alpine grassland gradient on the Tibetan Plateau.

    Science.gov (United States)

    Li, Xiaoliang; Zhang, Junling; Gai, Jingping; Cai, Xiaobu; Christie, Peter; Li, Xiaolin

    2015-08-01

    The diversity of arbuscular mycorrhizal fungi (AMF) in sedges on the Tibetan Plateau remains largely unexplored, and their contribution to soil aggregation can be important in understanding the ecological function of AMF in alpine ecosystems. Roots of Kobresia pygmaea C.B. Clarke and Carex pseudofoetida Kük. in alpine Kobresia pastures along an elevational transect (4149-5033 m) on Mount Mila were analysed for AMF diversity. A structural equation model was built to explore the contribution of biotic factors to soil aggregation. Sedges harboured abundant AMF communities covering seven families and some operational taxonomic units are habitat specific. The two plant species hosted similar AMF communities at most altitudes. The relative abundance of the two sedges contributed largely to soil macroaggregates, followed by extraradical mycorrhizal hyphae (EMH) and total glomalin-related soil protein (T-GRSP). The influence of plant richness was mainly due to its indirect influence on T-GRSP and EMH. There was a strong positive correlation between GRSP and soil total carbon and nitrogen. Our results indicate that mycorrhization might not be a major trait leading to niche differentiation of the two co-occurring sedge species. However, AMF contribute to soil aggregation and thus may have the potential to greatly influence C and N cycling in alpine grasslands.

  10. COMUNITY OF ARBUSCULAR MYCORRHIZAL FUNGI IN CULTIVATED SOIL WITH EUCALYPT, PINUS AND NATIVE FIELD, IN SANDY SOIL, SÃO FRANCISCO DE ASSIS, RS

    Directory of Open Access Journals (Sweden)

    Rodrigo Ferreira da Silva

    2009-10-01

    Full Text Available The aim of this work was to evaluate the community of arbuscular mycorrhizal fungi spores in five areas cultivated with eucalipt (Eucalyptus grandis W. Hill ex Maiden, pinus (Pinus elliottii Engelm. var. elliottii and native field, in arenization process, located in São Francisco de Assis-RS. The study of arbuscular mycorrhizal fungi spore community was carried out by direct and indirect identification and the diversity index determination. The analyzed areas were native field, 2 and 6 years-old eucalypt field and 2 and 12 years-old pinus field. The obtained results showed that the most frequent genera were Acaulospora, Scutellospora and Glomus. The highest diversity of species was found in area of native field, followed by 2 years-old Eucalyptus area. The Cluster analyses showed a similarity of the minimum 70 % to the species of FMAs identified through spores and 50 % to the areas being studied.

  11. Nursery inoculation with the arbuscular mycorrhizal fungus Glomus viscosum and its effect on the growth and physiology of hybrid artichoke seedlings

    Directory of Open Access Journals (Sweden)

    Angela Campanelli

    2011-07-01

    Full Text Available Most nurseries operating in Italy adopt high technologies and produce transplants that well suit and satisfy the grower’s need to produce high value crops. Mycorrhizas are discussed as a tool for improving and developing plant production in the nursery. Much research has been carried out on mycorrhizal symbiosis and we now know more about the symbiontic relationship between fungi and host plants. Plants receive numerous benefits from this symbiosis which are more macroscopic the earlier in the ontogenetic cycle this symbiosis is established. Therefore, it appears that the most effective period in which the inoculum should be made corresponds to the in-nursery growing stage. The earlier the plant is inoculated, the more evident the effect will be. In this study, several aspects related to the physiological foundations of arbuscular mycorrhiza in artichoke plants are presented. The main goal was to study the effects of mycorrhiza on the growth and physiological parameters of three hybrids of artichokes growing in the nursery. The experimental 3¥2 design included two treatments (with or without arbuscular mycorrhizal fungi and three hybrids of artichokes marketed by Nunhems (Opal F1, Madrigal F1, Concerto F1. Mycorrhizal plants have greater shoot length, leaf area, shoot and root fresh and dry mass, and root density. This also corresponded with increased photosynthetic rates and stomatal conductance of mycorrhizal plants. Mycorrhizal colonization improves relative water content and increases proline concentration in vegetal tissue. Inoculation produced the most beneficial effect on hybrid Madrigal F1 and on hybrid Opal F1; the best mycorrhizal affinity was enhanced when compared to hybrid Concerto F1. The results showed that mycorrhizal symbiosis stimulated the growth of inoculated seedlings providing a qualitatively good propagation material.

  12. Increased photosynthetic acclimation in alfalfa associated with arbuscular mycorrhizal fungi (AMF) and cultivated in greenhouse under elevated CO2.

    Science.gov (United States)

    Goicoechea, Nieves; Baslam, Marouane; Erice, Gorka; Irigoyen, Juan José

    2014-11-15

    Medicago sativa L. (alfalfa) can exhibit photosynthetic down-regulation when grown in greenhouse conditions under elevated atmospheric CO2. This forage legume can establish a double symbiosis with nitrogen fixing bacteria and arbuscular mycorrhizal fungi (AMF), which may increase the carbon sink effect of roots. Our aim was to assess whether the association of alfalfa with AMF can avoid, diminish or delay the photosynthetic acclimation observed in previous studies performed with nodulated plants. The results, however, showed that mycorrhizal (M) alfalfa at the end of their vegetative period had lower carbon (C) discrimination than non-mycorrhizal (NM) controls, indicating photosynthetic acclimation under ECO2 in plants associated with AMF. Decreased C discrimination was due to the acclimation of conductance, since the amount of Rubisco and the expression of genes codifying both large and small subunits of Rubisco were similar or slightly higher in M than in NM plants. Moreover, M alfalfa accumulated a greater amount of soluble sugars in leaves than NM plants, thus favoring a down-regulation effect on photosynthetic rates. The enhanced contents of sugars in leaves coincided with a reduced percentage of arbuscules in roots, suggesting decreased sink of carbohydrates from shoots to roots in M plants. The shorter life cycle of alfalfa associated with AMF in comparison with the NM controls may also be related to the accelerated photosynthetic acclimation in M plants. Further research is needed to clarify to what extent this behavior could be extrapolated to alfalfa cultivated in the field and subjected to periodic cutting of shoots under climatic change scenarios.

  13. Effect of arbuscular mycorrhizal fungi and phosphate fertilization on initial growth of six arboreal species of cerrado

    Directory of Open Access Journals (Sweden)

    Kenia Alves Pereira Lacerda

    2011-09-01

    Full Text Available This study evaluated the benefit of inoculation with arbuscular mycorrhizal fungi, Glomus clarum, for the initial growth of some native arboreal species of the Cerrado biome, namely gabiroba (Campomanesia cambessedeana, baru (Dipterix alata, jatobá (Hymenaea courbaril, ingá (Inga laurina, caroba (Jacaranda cuspidifolia and chichá (Sterculia striata, in unsterilized soil with low (0.02 mg L‑1 and high (0.2 mg L‑1 concentrations of P in the soil solution. Experiments were conducted in a greenhouse, using 1.5 kg vases, for up to 120 days. The experimental design for each arboreal species was completely randomized, with ten replicates in a 2x2 factorial design (inoculated and noninoculated seedlings, and two levels of phosphorus (P in the soil solution. Arboreal plants of the Cerrado biome showed increased mycorrhizal colonization from inoculation with Glomus clarum, except chichá, as this species showed a high indigenous colonization, not differing from the colonization promoted by inoculated fungi. Inoculation promoted increased growth in baru, gabiroba, ingá, caroba and chichá, increasing shoot dry matter (MSPA and root dry matter (MSR. In caroba, this effect was synergistic with application of P to the soil. Baru and jatobá showed increased dry matter with application of P to the soil only. The mycotrophy (mycorrhizal dependence of species and their response to inoculation and to phosphorus are discussed. In order to produce quality seedlings of caroba, gabiroba, chichá and ingá, combining inoculation with Glomus clarum and phosphate fertilization of the soil is recommended, while for jatobá and baru only the application of P to the soil is recommended.

  14. Effect of Arbuscular Mycorrhizal Fungi on Plant Biomass and the Rhizosphere Microbial Community Structure of Mesquite Grown in Acidic Lead/Zinc Mine Tailings

    OpenAIRE

    Solís-Domínguez, Fernando A.; Valentín-Vargas, Alexis; Chorover, Jon; Maier, Raina M.

    2011-01-01

    Mine tailings in arid and semi-arid environments are barren of vegetation and subject to eolian dispersion and water erosion. Revegetation is a cost-effective strategy to reduce erosion processes and has wide public acceptance. A major cost of revegetation is the addition of amendments, such as compost, to allow plant establishment. In this paper we explore whether arbuscular mycorrhizal fungi (AMF) can help support plant growth in tailings at a reduced compost concentration. A greenhouse exp...

  15. 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

  16. SOIL CHEMICAL PROPERTIES AND GROWTH OF SUNFLOWER (HELIANTHUS ANNUUS L. AS AFFECTED BY THE APPLICATION OF ORGANIC FERTILIZERS AND INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI

    Directory of Open Access Journals (Sweden)

    Apolino José Nogueira da Silva

    2015-02-01

    Full Text Available The use of organic fertilizers and the inoculation of mycorrhizal fungi in the cultivation of oil crops is essential to reduce production costs and minimize negative impacts on natural resources. A field experiment was conducted in an Argissolo Amarelo (Ultisol with the aim of evaluating the effects of fertilizer application and inoculation of arbuscular mycorrhizal fungi on the growth attributes of sunflower (Helianthus annuus L. and on soil chemical properties. The experiment was conducted at the Federal University of Rio Grande do Norte, Brazil, using a randomized block design with three replicates in a 4 × 2 factorial arrangement consisting of four treatments in regard to application of organic fertilizer (liquid biofertilizer, cow urine, mineral fertilizer, and unfertilized control and two treatments in regard to arbuscular mycorrhizal fungi (with and without mycorrhizal fungi. The results showed that the physiological attributes of relative growth rate and leaf weight ratio were positively influenced by fertilization, compared to the control treatment, likely brought about by the supply of nutrients from the fertilizers applied. The growth and productivity attributes were positively affected by mycorrhization.

  17. Arbuscular mycorrhizal status of medicinal plants in Rajshahi University Campus%拉杰沙希大学校园药用植物菌根研究

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Forty different medicinal plants were investigated for arbuscular mycorrhizal association in the Rajshahi University Campus in Bangladesh.The results indicated that 35 different plants were infected by AM (arbuscular mycorrhizal)fungi as found by trypan blue staining procedure.The percentage of root colonization by AM fungi varied from 13.3% to 100%.Mangifera indica and Morus indica have maximum percentage of colonization(100%).The intensity of root colonization were abundant in the plants belonging to the families Anacardiaceae,Asclepiadaceae,Moraceae,Leguminosae and Apocynaceae whereas the intensity of colonization of crop roots were moderate and poor belonging to Gramineae and Leguminosae.The presence of greater number of spore in soil was always associated with the incidence of abundant mycelia.In plant roots the formation of spore and mycelia was restricted by low pH.Number of mycorrhizal fungus spores ranged between 35 to100 per 100g air dried soil in different family respective soils.The frequency of mycorrhizal fungus infection showed positive correlation with soil pH,moisture,water holding capacity,texture,total nitrogen,organic carbon,phosphorus,calcium,potassium,and magnesium.Especially phosphorus and nitrogen in the soil greatly influenced the plant root infection by AM fungi.

  18. Endoproteolytic activities in pea roots inoculated with the arbuscular mycorrhizal fungus Glomus mosseae and/orAphanomyces euteiches in relation to bioprotection

    DEFF Research Database (Denmark)

    Slezack, S; DUMAS-GAUDOT, E; Rosendahl, Søren;

    1999-01-01

    was observed which was correlated with the amount of pathogen occurring in roots. Qualitative differences were seen among the endoproteolytic activities detected in roots inoculated with zoospores or mycelium. The constitutive as well as mycorrhizal and pathogen-induced activities were further characterized......Arbuscular mycorrhizal (AM) symbioses are known to play a role in increased resistance of plants against soilborne pathogens. Mechanisms involved in this phenomenon are not yet well understood. This work investigates possible roles of endoproteolytic activities in bioprotection of Pisum sativum...... roots by Glomus mosseae against Aphanomyces euteiches. First, it is demonstrated that bioprotection occurs only in pre-mycorrhizal plants. Second, endoproteolytic activities were analysed qualitatively and quantitatively during AM symbiosis, in plants infected with either zoospores or mycelium of A...

  19. Short-term temporal variation in sporulation dynamics of arbuscular mycorrhizal (AM) fungi and physico-chemical edaphic properties of wheat rhizosphere.

    Science.gov (United States)

    Panwar, Vipin; Meghvansi, M K; Siddiqui, Sazada

    2011-07-01

    In this study, we investigated the pattern of short-term temporal variation in the arbuscular mycorrhizal (AM) fungi and physico-chemical edaphic properties of some wheat growing areas of the Bundelkhand region, Central India. Rhizospheric soil samples were collected every month from December 2007 to May 2008 from four wheat growing sites around Jhansi (Bundelkhand region). AM fungal root colonization, sporulation and physico-chemical edaphic properties during this period were determined and compared to evaluate the dynamics of response of wheat towards the AMF along crop maturation. Maximum AMF root colonization recorded was 54.3% indicating that AMF, particularly in low phosphorus (P) soils, can be important even in case of less responsive crop like wheat. In the two out of four sites studied, the AMF spore density increased with the increase in soil temperature. Absence of this type of pattern in remaining two sites indicated that site-specific environmental and agricultural conditions may affect the degree of wheat response to AMF. It also suggested that AMF communities inhabiting agroecosystems may exhibit considerable temporal sporulation patterns. The maximum AMF colonization was observed during February-March 2008, whereas maximum AMF sporulation was noticed during March-April 2008. Statistically significant negative correlation of AMF spore density with pH, organic carbon (OC) and available P was observed in the one of the sites studied. Overall assessment of the data indicated that season and location significantly affected the interaction of AM fungi with winter wheat necessitating the further need to understand the ecology of AMF populations with reference to specific host species under different micro-climatic conditions of Bundelkhand region.

  20. Characterization of Three New Glutaredoxin Genes in the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis: Putative Role of RiGRX4 and RiGRX5 in Iron Homeostasis.

    Directory of Open Access Journals (Sweden)

    Elisabeth Tamayo

    Full Text Available Glutaredoxins (GRXs are small ubiquitous oxidoreductases involved in the regulation of the redox state in living cells. In an attempt to identify the full complement of GRXs in the arbuscular mycorrhizal (AM fungus Rhizophagus irregularis, three additional GRX homologs, besides the formerly characterized GintGRX1 (renamed here as RiGRX1, were identified. The three new GRXs (RiGRX4, RiGRX5 and RiGRX6 contain the CXXS domain of monothiol GRXs, but whereas RiGRX4 and RiGRX5 belong to class II GRXs, RiGRX6 belongs to class I together with RiGRX1. By using a yeast expression system, we observed that the newly identified homologs partially reverted sensitivity of the GRX deletion yeast strains to external oxidants. Furthermore, our results indicated that RiGRX4 and RiGRX5 play a role in iron homeostasis in yeast. Gene expression analyses revealed that RiGRX1 and RiGRX6 were more highly expressed in the intraradical (IRM than in the extraradical mycelium (ERM. Exposure of the ERM to hydrogen peroxide induced up-regulation of RiGRX1, RiGRX4 and RiGRX5 gene expression. RiGRX4 expression was also up-regulated in the ERM when the fungus was grown in media supplemented with a high iron concentration. These data indicate the two monothiol class II GRXs, RiGRX4 and RiGRX5, might be involved in oxidative stress protection and in the regulation of fungal iron homeostasis. Increased expression of RiGRX1 and RiGRX6 in the IRM suggests that these GRXs should play a key role in oxidative stress protection of R. irregularis during its in planta phase.

  1. Characterization of Three New Glutaredoxin Genes in the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis: Putative Role of RiGRX4 and RiGRX5 in Iron Homeostasis

    Science.gov (United States)

    Tamayo, Elisabeth; Benabdellah, Karim; Ferrol, Nuria

    2016-01-01

    Glutaredoxins (GRXs) are small ubiquitous oxidoreductases involved in the regulation of the redox state in living cells. In an attempt to identify the full complement of GRXs in the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis, three additional GRX homologs, besides the formerly characterized GintGRX1 (renamed here as RiGRX1), were identified. The three new GRXs (RiGRX4, RiGRX5 and RiGRX6) contain the CXXS domain of monothiol GRXs, but whereas RiGRX4 and RiGRX5 belong to class II GRXs, RiGRX6 belongs to class I together with RiGRX1. By using a yeast expression system, we observed that the newly identified homologs partially reverted sensitivity of the GRX deletion yeast strains to external oxidants. Furthermore, our results indicated that RiGRX4 and RiGRX5 play a role in iron homeostasis in yeast. Gene expression analyses revealed that RiGRX1 and RiGRX6 were more highly expressed in the intraradical (IRM) than in the extraradical mycelium (ERM). Exposure of the ERM to hydrogen peroxide induced up-regulation of RiGRX1, RiGRX4 and RiGRX5 gene expression. RiGRX4 expression was also up-regulated in the ERM when the fungus was grown in media supplemented with a high iron concentration. These data indicate the two monothiol class II GRXs, RiGRX4 and RiGRX5, might be involved in oxidative stress protection and in the regulation of fungal iron homeostasis. Increased expression of RiGRX1 and RiGRX6 in the IRM suggests that these GRXs should play a key role in oxidative stress protection of R. irregularis during its in planta phase. PMID:26900849

  2. Microarray analysis and functional tests suggest the involvement of expansins in the early stages of symbiosis of the arbuscular mycorrhizal fungus Glomus intraradices on tomato (Solanum lycopersicum).

    Science.gov (United States)

    Dermatsev, Vladimir; Weingarten-Baror, Carmiya; Resnick, Nathalie; Gadkar, Vijay; Wininger, Smadar; Kolotilin, Igor; Mayzlish-Gati, Einav; Zilberstein, Avia; Koltai, Hinanit; Kapulnik, Yoram

    2010-01-01

    Arbuscular mycorrhizal (AM) symbiosis occurs between fungi of the phylum Glomeromycota and most terrestrial plants. However, little is known about the molecular symbiotic signalling between AM fungi (AMFs) and non-leguminous plant species. We sought to further elucidate the molecular events occurring in tomato, a non-leguminous host plant, during the early, pre-symbiotic stage of AM symbiosis, i.e. immediately before and after contact between the AMF (Glomus intraradices) and the host. We adopted a semi-synchronized AMF root infection protocol, followed by genomic-scale, microarray-based, gene expression profiling at several defined time points during pre-symbiotic AM stages. The microarray results suggested differences in the number of differentially expressed genes and in the differential regulation of several functional groups of genes at the different time points examined. The microarray results were validated and one of the genes induced during contact between AMF and tomato, the expansin-like EXLB1, was functionally analysed. Expansins, encoded by a large multigene family, facilitate plant cell expansion. However, no biological or biochemical function has yet been established for plant-originated expansin-like proteins. EXLB1 transcripts were localized early during the association to cells that may perceive the fungal signal, and later during the association in close proximity to sites of AMF hypha-root colonization. Moreover, in transgenic roots, we demonstrated that a reduction in the steady-state level of EXLB1 transcript was correlated with a reduced rate of infection, reduced arbuscule expansion and reduced AMF spore formation.

  3. Estimation of the biomass of arbuscular mycorrhizal fungi in a linseed field

    DEFF Research Database (Denmark)

    Olsson, P.A.; Thingstrup, I.; Jakobsen, I.;

    1999-01-01

    Linseed was grown in field plots included in a long-term P fertilisation experiment (0, 15 or 30 kg P ha(-1) yr(-1) for 20 yr). Two months before sowing, half of each plot man applied with dazomet to prevent the formation of arbuscular mycorrhiza (AM). The biomass of different groups of micro-organisms...

  4. Entrophospora schenckii and Pacispora franciscana, arbuscular mycorrhizal fungi (Glomeromycota new for Europe and Poland, respectively

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-08-01

    Full Text Available Morphological properties of spores of Pacispora franciscana, as well as spores and mycorrhizae of Entrophospora schenckii, arbuscular fungi of the phylum Glomeromycota found for the first time in Poland and Europe, respectively, are described and illustrated. Additionally, the known distribution of the two fungi is presented.

  5. Sugar beet waste and its component ferulic acid inhibits external mycelium of arbuscular mycorrhizal fungus

    DEFF Research Database (Denmark)

    Medina, Almudena; Jakobsen, Iver; Egsgaard, Helge

    2011-01-01

    External arbuscular mycorrhiza (AM) mycelium plays an important role in soil while interacting with a range of biotic and abiotic factors. One example is the soil organic amendment sugar beet waste. The fermented Aspergillus niger–sugar beet waste (ASB) increases growth and P uptake by the AM...

  6. Succession of arbuscular mycorrhizal fungi in a deflation hollow of the Słowiński National Park, Poland

    Directory of Open Access Journals (Sweden)

    Mariusz Tadych

    2014-01-01

    Full Text Available In the years 1994-1995, the occurrence of arbuscular mycorrhizal fungi (AMF and arbuscular mycorrhizae (AM in eight successional stages of vegetation of a deflation hollow no. 12 of the Łeba Bar, Poland, was investigated. Early successional stages were colonized by members of the families Gramineae and Juncaceae, being gradually replaced by ericaceous plants in the middle and later stages and by trees in the most advanced stage corresponding to the Empetro nigri-Pinetum plant association. From the 96 soil samples collected, 21 species in three genera of AMF were recovered. The fungi most frequently found were members of the genus Acaulospora. The overall spore abundance, the species_ richness of AMF and the level of AM colonisation increased from stage 1 to reach a maximum in the middle stages and then gradually declined, being lowest in the forested stage 8. The values of the overall spore abundance and those of the abundances of the most frequently occurring AMF species strongly evidenced functioning in nature of the process of host-dependent differentiation of AMF communities. Of the five most numerously represented AMF species, the early colonizer and quickly diminishing in later successional stages was Glomus 107. The mid-late successor was A. koskei, and the latest - Glomus aggregatum. All measures of AMF presence negatively correlated with the content of organic C in the soil and most of them were negatively correlated with soil N-NO3 and P concentrations. In contrast, the occurrence of AMY and AM generally was positively correlated with soil pH and the K content of the soil.

  7. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening

    Science.gov (United States)

    The roots of plants interact with soil mycorrhizal fungi to facilitate soil nutrient acquisition by the plant and carbon transfer to the fungus. Here we use tomato fruit ripening mutations to demonstrate that this root interaction communicates with and supports genetic mechanisms associated with th...

  8. Metabolic activity of Glomus intraradices in Arum- and Paris-type arbuscular mycorrhizal colonization

    NARCIS (Netherlands)

    van Aarle, IM; Cavagnaro, TR; Smith, SE; Dickson, S

    2005-01-01

    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 structure

  9. Spore population, colonization, species diversity and factors influencing the association of arbuscular mycorrhizal fungi with litchi trees in India.

    Science.gov (United States)

    Kumar, Vinod; Kumar, Rajesh; Kumar, Ajit; Anal, Dubedi

    2016-01-01

    Abundance and diversity of arbuscular mycorrhizal fungi (AMF) in association with litchi (Litchi chinensis Sonn.) trees were studied during 2012-2013, where orchard soil had high pH (7.42-9.53) and salinity (0.07- 0.39 dSm(-1)). A total of 105 rhizospheric soil and root samples were collected considering variables like location, age of tree, cultivar and production management. Results showed that spore count was in the range of 1-22 g(-1) soil. All the examined root segments had colonization of AMF, which ranged between 3.3 to 90.0%. AMF community comprised of Glomus mosseae, G. intaradices, G. constricta, G. coronatum, G. fasciculatum, G. albidum, G. hoi, G. multicauli, Acaulospora scrobiculata, A. laevis, Rhizophagus litchi and Entrophosphora infrequens. Higher spore density and AMF colonization were observed at medium level (13-28 kg ha(-1)) of available phosphorus that decreased ('r' = -0.21 for spore density, -0.48 for root colonization) with increasing soil phosphorus. While nitrogen did not influence the AMF association, a weak negative linear relationship with AMF colonization ('r' = -0.30) was apparent in the medium level (112-200 kg ha(-1)) of potash. Micronutrients (Zn, Fe, Cu, Mn and B) did not affect spore density (zero or a very weak linear correlation) but influenced root colonization ('r' = -0.53 to -0.44), the effect being more prominent above critical limits. Nutritionally sufficient, irrigated litchi orchards had greater spore count (46% samples having 5-22 spores g(-1) soil) and colonization (> 50% in 37.4% roots examined) than nutrient deficient, non-irrigated orchards, indicating essentiality of a threshold nutrients and moisture regime for the association. AMF symbiosis was influenced by cultivar (greater in 'China'), but tree age was not correlated to mycorrhizal association. A consortium of native species coupled with the understanding of nutrient effects on AMF would be useful for field application in litchi.

  10. Effectiveness of arbuscular mycorrhizal fungi in the protection of olive plants against oxidative stress induced by drought

    Directory of Open Access Journals (Sweden)

    Mohamed O. Fouad

    2014-06-01

    Full Text Available Olive trees are often subjected to a long dry season with low water availability which induces oxidative stress. The present study was conducted to evaluate the effectiveness of native Rhizophagus manihotis (Rma and non-native Funneliformis mosseae (Fmo arbuscular mycorrhizal (AM fungi (AMF in enhancing olive protection against oxidative stress induced by water deficit. Olive plantlets, cv. Picholine marocaine, were inoculated (AM-plants or not (NM-plants with Rma or Fmo and subjected to well-watered (75% of field capacity or water-stressed (25% of field capacity conditions. After two months, obtained results showed that water stress significantly decreased growth and biomass production of NM-plants, but AMF alleviated the detrimental effects of water deficit on the growth of olive plants. Inoculation with Rma increased shoot height by 120%, root length by 56%, fresh weight by 170% (shoot and 210% (root, and dry weight by 220% (shoot and 220% (root compared to NM-plants. AM colonization enhanced drought tolerance in terms of protection against oxidative stress. Mycorrhizal plants showed lower levels of hydrogen peroxide (H2O2, malondialdehyde (MDA and electrolyte leakage (EL than NM-plants. Rma colonization decreased two times H2O2, 2.6 times MDA and two times EL levels compared to NM-plants. This protective effect seems to be due to the enhanced activities of superoxide dismutase (534 U mg-1 protein, catalase (298 U mg-1 protein, guaiacol peroxidase (47 U mg-1 protein, and ascorbate peroxidase (305 U mg-1 protein which were highest in Rma-plants. Moreover, Rma-plants showed the lowest oxidative damage to lipid and highest soluble protein content. Thus, the native AMF Rma ought to be considered as a biological tool for enhancing olive tolerance to drought.

  11. [Effects of Arbuscular Mycorrhizal Fungi on the Growth and Ce Uptake of Maize Grown in Ce-contaminated Soils].

    Science.gov (United States)

    Wang, Fang; Guo, Weil; Ma, Peng-kun; Pan, Liang; Zhang, Jun

    2016-01-15

    A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal (AM) fungi Glomus aggregatum (GA) and Funneliformis mosseae (FM) on AM colonization rate, biomass, nutrient uptake, C: N: P stoichiometric and Ce uptake and transport by maize (Zea mays L.) grown in soils with different levels of Ce-contaminated (100, 500 and 1000 mg x kg(-1)). The aim was to provide basic data and technical support for the treatment of soils contaminated by rare earth elements. The results indicated that symbiotic associations were successfully established between the two isolates and maize, and the average AM colonization rate ranged from 7. 12% to 74.47%. The increasing concentration of Ce in soils significantly decreased the mycorrhizal colonization rate, biomass, nutrition contents and transport rate of Ce from root to shoot of maize, and significantly increased C: P and N: P ratios and Ce contents in shoot and root of maize. Both AM fungi inoculations promoted the growth of maize, but the promoting role of FM was more significant than that of GA in severe Ce-contaminated soils. There were no significant differences in the growth of maize between two AM fungi in mild and moderate Ce-contaminated soils. Inoculation with AM fungi significantly improved nutritional status of maize by increasing nutrient uptake and decreasing C: N: P ratios. GA was more efficient than FM in enhancing nutrient uptake in mild and moderate Ce-contaminated soils, while FM was more efficient in severe Ce-contaminated soils. Moreover, inoculation with AM fungi significantly increased Ce contents of shoot and root in mild Ce-contaminated soils, but had no significant effect on Ce contents of maize in moderate and severe Ce-contaminated soils, and promoted the transport of Ce from root to shoot. The experiment demonstrates that AM fungi can alleviate toxic effects of Ce on plants and have a potential role in the phytoremediation of soils contaminated by rare earth elements.

  12. A Preliminary Investigation on Species Diversity of Arbuscular Mycorrhizal Fungi in Rosary%玫瑰园AM真菌物种多样性的初步研究

    Institute of Scientific and Technical Information of China (English)

    董磊; 李敏; 郭绍霞

    2012-01-01

    丛枝菌根(AM)真菌多样性是当前菌根学领域研究热点之一.玫瑰是世界性花卉,在我国的栽培面积越来越大.为了解玫瑰根区土壤中AM真菌多样性与资源的分布状况,于2010年11月在济南平阴玫瑰园选择样地,采集了5个不同种/品种的蔷薇属(Rosa)植物根区土样,采用湿筛倾注——蔗糖离心法分离AM真菌,测定其物种丰度、频度、孢子密度、相对多度、重要值、多样性指数等.共分离到AM真菌4属28种,球囊霉属(Glomus)出现的频度最高,其次是无梗囊霉属(Acaulospora).AM真菌孢子密度以‘紫枝’玫瑰(R.rugosa‘zizhi’)与山刺玫(R.davurica)根区的最高,野蔷薇(R.multiflora)最低;种丰度以‘丰花’(R.rugosa‘fenghua’)玫瑰最高;黄球囊霉(G.fulvum)是‘丰花’玫瑰的优势种,缩球囊霉(G.constrictum)是‘紫枝’玫瑰的优势种,网状球囊霉(G.reticulatum)是保加利亚白玫瑰(R.damascene)和山刺玫的优势种,双网无梗囊霉(A.bireticulata)是野蔷薇的优势种.认为玫瑰根区土壤中具有丰富的AM真菌物种多样性.本研究为进一步深入研究花卉植物根区AM真菌多样性提供了基础和依据.%Species diversity of arbuscular mycorrhizal (AM) fungi is one of research hots in mycorrhizology. Rose is a global flower, and its growing area increases year by year. In order to understand species diversity and resources distribution of AM fungi in root zone soil of rose plants, sampling sites were selected in Pingyin rosary in Jinan in November 2010, and the root zone soil sample of 5 different varieties of Rosa were collected to determine the diversity of arbuscular mycorrhizal fungi. Spores of AM fungi were identiffed to reveal the species richness, frequency, spore density, relative abundance, importance value and Shannon - Wiener indices of AM fungi. A total of 28 species belonging to 4 genera were identified according to the morphological characteristics of the spores

  13. Production of Plant Growth-Regulating Substances by the Vesicular-Arbuscular Mycorrhizal Fungus Glomus mosseae

    OpenAIRE

    Barea, José M.; Azcón-Aguilar, Concepción

    1982-01-01

    Glomus mosseae, a representative species of Endogonaceae (Phycomycetes) able to form vesicular-arbuscular mycorrhiza, was investigated for phytohormone production. Spores of G. mosseae were axenically germinated in water, and the resultant mycelial growth was assayed by standard procedures for extracting plant hormones from microbial cultures. Paper partition chromatography and specific bioassays were used to separate and identify plant growth-regulating substances. The microorganism synthesi...

  14. Occurrence of arbuscular mycorrhizal fungi in high altitude sites of the Patagonian Altoandina region in Nahuel Huapi National Park (Argentina

    Directory of Open Access Journals (Sweden)

    María Silvana Velázquez

    Full Text Available ABSTRACT Knowledge of the occurrence and diversity of arbuscular mycorrhizal fungi (AMF in National Parks is essential for the establishment of policies for conservation. The aim of this study was to characterize the AMF communities in the Patagonian Altoandina region in Nahuel Huapi National Park, Argentina. We surveyed AMF spores associated with the rhizospheres of 9 plant species in the Patagonian Steppe (PS, Challhuaco Hill (ChH, Catedral Hill (CH, and Tronador Hill (TH regions and detected a total of 27 Glomeromycota species. Acaulospora laevis was dominant at all sites. The AMF community was dominated by Acaulosporaceae, as regards the number of species and contribution of each one to the total number of spores. Three Glomeromycota families were detected at PS, the site with the lowest elevation; whereas five to six families were detected at ChH, CH, and TH. Cluster analysis indicated that the AMF communities were grouped according to habitat. We concluded that certain patterns of the AMFcommunity structure detected were equivalent to those of high-altitude environments from other studies, while others were unique to the Patagonian region; thus suggesting that historical influences like dispersion and speciation played a critical role in shaping AMF community composition in such high-altitude environments.

  15. Arbuscular mycorrhizal fungi in national parks, nature reserves and protected areas worldwide: a strategic perspective for their in situ conservation.

    Science.gov (United States)

    Turrini, Alessandra; Giovannetti, Manuela

    2012-02-01

    Soil fungi play a crucial role in producing fundamental ecosystem services such as soil fertility, formation and maintenance, nutrient cycling and plant community dynamics. However, they have received little attention in the field of conservation biology. Arbuscular mycorrhizal fungi (AMF) are beneficial soil symbionts fulfilling a key function in the complex networks of belowground/aboveground biotic interactions as they live in association with the roots of most (80%) land plant families and influence not only soil fertility but also plant nutrition, diversity and productivity. The diversity of AMF communities can decline due to habitat loss and anthropogenic disturbance, especially in agro-ecosystems, and many valuable ecotypes could become extinct before they are even discovered. Consequently, long-term strategies are urgently needed to ensure their conservation in habitats where they naturally occur and have evolved. Protected areas, where living organisms are under the care of national and international authorities, represent an appropriate place for the in situ conservation of AMF, providing them with adapted situations together with established complex networks of interactions with different components within each specific ecosystem. Here, we review data available about the main present-day threats to AMF and the current state of knowledge about their occurrence in protected sites worldwide, providing a checklist of national parks and nature reserves where they have been reported. The aim was to offer a strategic perspective to increase awareness of the importance of conserving these beneficial plant symbionts and of preserving their biodiversity in the years to come.

  16. Land-Cover Legacy Effects on Arbuscular Mycorrhizal Abundance in Human and Wildlife Dominated Systems in Tropical Savanna

    Directory of Open Access Journals (Sweden)

    Geofrey E. Soka

    2016-01-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF can be important mutualists to plant hosts in acquiring soil nutrients. Past work has not explored whether previous land-cover history influences current AMF abundance in croplands and whether different land-cover histories in grazed but not cultivated areas influence AMF. This study was conducted to assess the effects of land-cover history in and near Serengeti National Park on AMF abundance in areas with three different land uses. The results showed that land-cover history influenced a number of soil physicochemical properties following conversion of grassland to cropland or woodland to cropland during the past 27 years. Different original land cover generally did not significantly influence current AMF abundance in croplands or livestock-grazed soils. However, livestock-grazed current grasslands that were formerly woodlands had lower AMF abundance than sites that had been grasslands since 1984. These results suggest that lower AMF abundance in livestock-grazed and cropland areas as compared to protected wildlife-grazed areas may reflect reduced total carbon inputs and higher disturbance and are not strongly influenced by the legacy of previous land cover. Given that recent studies have detected legacy effects on AMF, such effects may reflect more the impact on the taxonomic composition of AMF rather than their total abundance.

  17. 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.

  18. Land-use intensity and host plant identity interactively shape communities of arbuscular mycorrhizal fungi in roots of grassland plants.

    Science.gov (United States)

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

    2015-03-01

    We studied the effect of host plant identity and land-use intensity (LUI) on arbuscular mycorrhizal fungi (AMF, Glomeromycota) communities in roots of grassland plants. These are relevant factors for intraradical AMF communities in temperate grasslands, which are habitats where AMF are present in high abundance and diversity. In order to focus on fungi that directly interact with the plant at the time, we investigated root-colonizing communities. Our study sites represent an LUI gradient with different combinations of grazing, mowing, and fertilization. We used massively parallel multitag pyrosequencing to investigate AMF communities in a large number of root samples, while being able to track the identity of the host. We showed that host plants significantly differed in AMF community composition, while land use modified this effect in a plant species-specific manner. Communities in medium and low land-use sites were subsets of high land-use communities, suggesting a differential effect of land use on the dispersal of AMF species with different abundances and competitive abilities. We demonstrate that in these grasslands, there is a small group of highly abundant, generalist fungi which represent the dominating species in the AMF community.

  19. Isolated root caps, border cells, and mucilage from host roots stimulate hyphal branching of the arbuscular mycorrhizal fungus, Gigaspora gigantea.

    Science.gov (United States)

    Nagahashi, Gerald; Douds, David D

    2004-09-01

    Unlike previous reports that have shown that water soluble and volatile compounds from roots or root exudates play an important role in precolonization events during arbuscular mycorrhizal (AM) fungus-host root interactions (Bécard & Piché 1989, Giovannetti et al. 1993), the results shown here deal with particulate and viscous fractions isolated from host roots. Root caps and a slow sedimenting particulate fraction (SSPF) were rapidly isolated and separated from Ri T-DNA transformed carrot roots (D. carota) grown in liquid culture. In addition, border cells (BC) and mucilage were isolated from aseptically grown corn seedlings (Zea mays). Root caps, SSPF (composed mainly of small root cap fragments and some BCs), BCs, and mucilage all had an associated AM fungus hyphal branching stimulator. Root caps stored for 5 d at 4 degrees C appeared to either synthesize or slowly release the branching stimulator. Also, isolated root caps from roots grown in the absence of P contained more branch stimulating activity than those isolated from roots grown in the presence of P. Although the branching stimulation activity in particulate fractions was low compared to that of the exudate, the particulate fractions can stick to the root surface at considerable distances from the root tip. This may be significant during the infection and colonization of host roots at sites far removed from the primary location of exudation.

  20. Soil and geography are more important determinants of indigenous arbuscular mycorrhizal communities than management practices in Swiss agricultural soils.

    Science.gov (United States)

    Jansa, Jan; Erb, Angela; Oberholzer, Hans-Rudolf; Smilauer, Petr; Egli, Simon

    2014-04-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous soil fungi, forming mutualistic symbiosis with a majority of terrestrial plant species. They are abundant in nearly all soils, less diverse than soil prokaryotes and other intensively studied soil organisms and thus are promising candidates for universal indicators of land management legacies and soil quality degradation. However, insufficient data on how the composition of indigenous AMF varies along soil and landscape gradients have hampered the definition of baselines and effect thresholds to date. Here, indigenous AMF communities in 154 agricultural soils collected across Switzerland were profiled by quantitative real-time PCR with taxon-specific markers for six widespread AMF species. To identify the key determinants of AMF community composition, the profiles were related to soil properties, land management and site geography. Our results indicate a number of well-supported dependencies between abundances of certain AMF taxa and soil properties such as pH, soil fertility and texture, and a surprising lack of effect of available soil phosphorus on the AMF community profiles. Site geography, especially the altitude and large geographical distance, strongly affected AMF communities. Unexpected was the apparent lack of a strong land management effect on the AMF communities as compared to the other predictors, which could be due to the rarity of highly intensive and unsustainable land management in Swiss agriculture. In spite of the extensive coverage of large geographical and soil gradients, we did not identify any taxon suitable as an indicator of land use among the six taxa we studied.

  1. Effect of arbuscular mycorrhizal fungi on the essential oil composition and antioxidant activity of black pepper (Piper nigrum L.

    Directory of Open Access Journals (Sweden)

    Shirlley F. M Da Luz

    2016-07-01

    Full Text Available Summary. Piper nigrum plants were inoculated by spores of arbuscular mycorrhizal fungi (AMF and after 120 days, the essential oils (EO and extracts of leaves and roots were obtained. The AMF inoculation promoted a decrease of sesquiterpene hydrocarbons (25.4% to 10.6% and an increase of oxygenated sesquiterpenes (67.0% to 82.7% in the leaf EO. In addition, an increase of the main compounds α-bisabolol (32.3% to 48.5% and elemol (11.4% to 23.2% was observed. However, in the roots EO the main compounds were monoterpenes as camphene, sabinene and limonene, which did not display variation. The leaf extract showed a significant variation in total phenolic content (6.8 ± 0.2 to 16.4 ± 1.0 mg AGE/g and antioxidant activity (12.3 ± 2.0 to 73.7 ± 1.4 mg TE/g. The oils and extracts of the roots remained almost unchanged, suggesting that the inoculation with AMF induces a systemic response in P. nigrum and affects mainly the leaves. Industrial relevance. Piper nigrum essential oil is used as flavoring, antimicrobial and antioxidant agent in food preservation. These proprieties are attributed to the presence of the oxygenated sesquiterpenoids α-bisabolol and elemol, which displayed an increased its content after AMF inoculation. Keywords. Black pepper; AMF colonization; α-bisabolol; phenolic compounds; antioxidant activity

  2. Foliar spray with vermiwash modifies the Arbuscular mycorrhizal dependency and nutrient stoichiometry of Bhut Jolokia (Capsicum assamicum).

    Science.gov (United States)

    Khan, Mohammad Haneef; Meghvansi, Mukesh K; Gupta, Rajeev; Veer, Vijay; Singh, Lokendra; Kalita, Mohan C

    2014-01-01

    Vermiwash (VW), a liquid extract obtained from vermicomposting beds, is used as an organic fertilizer for crop plants. The current study investigated the effect of a vermiwash foliar spray on the response of bhut jolokia (Capsicum assamicum) exposed to two different arbuscular mycorrhizal fungi (AMF: Rhizophagus irregularis, RI and G. mosseae, GM) in acidic soil under naturally ventilated greenhouse conditions. The VW spray significantly influenced the growth of plants receiving the dual treatment of AMF+VW. Plant growth was more prominent in the GM+VW treatment group than that in the RI+VW treatment group. The plant-AMF interactions in relation to growth and nutrient requirements were also significantly influenced by the application of VW. Interestingly, the VW treatment appeared to contribute more N to plants when compared to that under the AMF treatment, which led to changes in the C:N:P stoichiometry in plant shoots. Furthermore, the increased potassium dependency, as observed in the case of the dual treatments, suggests the significance of such treatments for improving crop conditions under salt stress. Overall, our study shows that the VW foliar spray modifies the response of a crop to inoculations of different AMF with regard to growth and nutrient utilization, which has implications for the selection of an efficient combination of nutrient source for improving crop growth.

  3. Change in morphological properties of root and aerial parts of chickpea under drought stress, arbuscular mycorrhizal fungi and rhizobium treatments

    Directory of Open Access Journals (Sweden)

    S. Morad

    2016-09-01

    Full Text Available To evaluate the effect of arbuscular mycorrhizal (AM fungi (Glomus mosseae and Glomus intraradices and Mesorhizobium Ciceri bacteria at three soil moisture levels [28% (field capacity, FC, 15% (-5 bar suction and 9% (-10 bar tension by weight] on morphological properties of root and aerial parts of chickpea, a greenhouse factorial experiment, arranged as a complete randomized design, was conducted in a sterilized soil. Results showed that moisture treatment had significance effect on number of pods, number of seeds, fresh and dry weight of root and aerial parts, plant height and root length and volume. Application of Mesorhizobium was effective on number of nodes, number of pods, number of seeds, fresh and dry weight of root and aerial parts, plant height, root length and volume. Glomus mosseae had significant effect on plant height. Interaction of moisture and AM fungi was significant on fresh and dry weight of root and aerial parts. Interaction effect of Mesorhizobium and soil moisture was only significant on number of nodes. In general, the highest fresh and dry weight of aerial parts (44.6 and 10.53 grams, respectively was obtained by inoculation of chickpea by rhizobium bacteria and Glomus mosseae at FC moisture level, and AM fungi Glomus mosseae was more efficient compared to Glomus intraradices in both drought stress and without stress conditions.

  4. Effect of biosolids-derived triclosan and triclocarban on the colonization of plant roots by arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Prosser, R S; Lissemore, L; Shahmohamadloo, R S; Sibley, P K

    2015-03-01

    Arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship with the majority of crop plants. AMF provide plants with nutrients (e.g., P), modulate the effect of metal and pathogen exposure, and increase tolerance to moisture stress. The benefits of AMF to plant growth make them important to the development of sustainable agriculture. The land application of biosolids is becoming an increasingly common practice in sustainable agriculture, as a source of nutrients. However, biosolids have been found to contain numerous pharmaceutical and personal care products including antimicrobial chemicals such as triclosan and triclocarban. The potential risks that these two compounds may pose to plant-AMF interactions are poorly understood. The current study investigated whether biosolids-derived triclosan and triclocarban affect the colonization of the roots of lettuce and corn plants by AMF. Plants were grown in soil amended with biosolids that contained increasing concentrations of triclosan (0 to 307 μg/g dw) or triclocarban (0 to 304 μg/g dw). A relationship between the concentration of triclosan or triclocarban and colonization of plants roots by AMF was not observed. The presence of biosolids did not have a significant (p>0.05) effect on percent colonization of corn roots but had a significant, positive effect (ptriclosan and triclocarban did not inhibit the colonization of crop plant roots by AMF.

  5. Arbuscular mycorrhizal fungi increased early growth of two nontimber forest product species Dyera polyphylla and Aquilaria filaria under greenhouse conditions.

    Science.gov (United States)

    Turjaman, Maman; Tamai, Yutaka; Santoso, Erdy; Osaki, Mitsuru; Tawaraya, Keitaro

    2006-10-01

    Nontimber forest products (NTFPs) represent an important source of income to millions of people in tropical forest regions, but some NTFP species have decreased in number and become endangered due to overexploitation. There is increasing concern that the planting stocks of Dyera polyphylla and Aquilaria filaria are not sufficient to sustain the yield of NTFPs and promote forest conservation. The objective of this study was to determine the effect of two arbuscular mycorrhizal (AM) fungi, Glomus clarum and Gigaspora decipiens, on the early growth of two NTFP species, D. polyphylla and A. filaria, under greenhouse conditions. The seedlings of both species were inoculated with G. clarum or G. decipiens, or uninoculated (control) under greenhouse conditions. Percentage of AM colonization, plant growth, survival rate, and nitrogen (N) and phosphorus (P) concentrations were measured after 180 days of growth. The percentage of AM colonization of D. polyphylla and A. filaria ranged from 87 to 93% and from 22 to 39%, respectively. Colonization by G. clarum and G. decipiens increased plant height, diameter, and shoot and root dry weights. Shoot N and P concentrations of the seedlings were increased by AM colonization by as much as 70-153% and 135-360%, respectively. Survival rates were higher in the AM-colonized seedlings at 180 days after transplantation than in the control seedlings. The results suggest that AM fungi can accelerate the establishment of the planting stocks of D. polyphylla and A. filaria, thereby promoting their conservation ecologically and sustaining the production of these NTFPs economically.

  6. Variability in growth, nutrition and phytochemical constituents of Plectranthus amboinicus (Lour Spreng. as influenced by indigenous arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Sevanan Rajeshkumar

    2008-07-01

    Full Text Available A study was conducted under greenhouse nursery condition on the efficacy of seven indigenous arbuscular mycorrhizal (AM fungi in the improvement of growth, biomass, nutrition and phytochemical constituents, namely total phenols, ortho dihydroxy phenols, flavonoids, alkaloids, tannins and saponins, in the roots and leaves of Plectranthus amboinicus (Lour Spreng. Seedlings were raised in polythene bags containing soil inoculated with isolates of seven different indigenous AM fungi, viz. Acaulospora bireticulata, A. scrobiculata, Gigaspora margarita, Glomus aggregatum, G. mosseae, G. geosporum, and Scutellospora heterogama. P. amboinicus seedlings raised in the presence of AM fungi generally showed an increase in plant growth, nutritional status and phytochemical constituents over those grown in the absence of AM fungi. The extent of growth, biomass, nutritional status and phytochemical constituents enhanced by AM fungi varied with the species of AM fungi inhabiting the roots and leaves of P. amboinicus seedlings. Considering the various plant growth parameters, nutritional status of the plant, total phenols, ortho dihydroxy phenols, alkaloids , flavonoids , tannins, and saponins in the roots and leaves, it was observed that Gigaspora margarita is the best AM symbiont for P. amboinicus used in this experiment.

  7. Transfer of N and P from intact or decomposing roots of pea to barley interconnected by an arbuscular mycorrhizal fungus

    DEFF Research Database (Denmark)

    Johansen, A.; Jensen, E.S.

    1996-01-01

    The role of arbuscular mycorrhizas in the transfer of N and P between pea (Pisum sativum L.) and barley (Hordeum vulgare L.) plants was studied in a controlled environment. The plants were grown together in PVC containers, either in symbiosis with Glomus intraradices Schenck and Smith or as non......-mycorrhizal controls, and with their root systems separated by an intermediate buffer zone (2 cm), confined by fine nylon mesh. The pea donor plants were supplied simultaneously with N-15 and P-32, using a split-root labelling technique, in order to follow the flow of N and P to the barley receiver plants during 60 d...... of growth. In half of the containers, the donor-plant shoot was removed 42 d after the start of labelling and the roots were left in the soil to decompose. The reverse transfer of N and P, from barley donor to pea receiver plants was also measured to allow calculation of the net transfer through hyphae...

  8. Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

    Science.gov (United States)

    Jiang, Qiu-Yun; Zhuo, Feng; Long, Shi-Hui; Zhao, Hai-Di; Yang, Dan-Jing; Ye, Zhi-Hong; Li, Shao-Shan; Jing, Yuan-Xiao

    2016-02-01

    A greenhouse pot experiment was conducted to study the impact of arbuscular mycorrhizal fungi‑Glomus versiforme (Gv) and Rhizophagus intraradices (Ri) on the growth, Cd uptake, antioxidant indices [glutathione reductase (GR), ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), ascorbate (ASA), glutathione (GSH) and malonaldehyde (MDA)] and phytochelatins (PCs) production of Lonicera japonica in Cd-amended soils. Gv and Ri significantly increased P acquisition, biomass of shoots and roots at all Cd treatments. Gv significantly decreased Cd concentrations in shoots and roots, and Ri also obviously reduced Cd concentrations in shoots but increased Cd concentrations in roots. Meanwhile, activities of CAT, APX and GR, and contents of ASA and PCs were remarkably higher in Gv/Ri-inoculated plants than those of uninoculated plants, but lower MDA and GSH contents in Gv/Ri-inoculated plants were found. In conclusion, Gv and Ri symbiosis alleviated Cd toxicity of L. japonica through the decline of shoot Cd concentrations and the improvement of P nutrition, PCs content and activities of GR, CAT, APX in inoculated plants, and then improved plant growth. The decrease of shoot Cd concentrations in L. japonica inoculated with Gv/Ri would provide a clue for safe production of this plant from Cd-contaminated soils.

  9. Heart of endosymbioses: transcriptomics reveals a conserved genetic program among arbuscular mycorrhizal, actinorhizal and legume-rhizobial symbioses.

    Directory of Open Access Journals (Sweden)

    Alexandre Tromas

    Full Text Available To improve their nutrition, most plants associate with soil microorganisms, particularly fungi, to form mycorrhizae. A few lineages, including actinorhizal plants and legumes are also able to interact with nitrogen-fixing bacteria hosted intracellularly inside root nodules. Fossil and molecular data suggest that the molecular mechanisms involved in these root nodule symbioses (RNS have been partially recycled from more ancient and widespread arbuscular mycorrhizal (AM symbiosis. We used a comparative transcriptomics approach to identify genes involved in establishing these 3 endosymbioses and their functioning. We analysed global changes in gene expression in AM in the actinorhizal tree C. glauca. A comparison with genes induced in AM in Medicago truncatula and Oryza sativa revealed a common set of genes induced in AM. A comparison with genes induced in nitrogen-fixing nodules of C. glauca and M. truncatula also made it possible to define a common set of genes induced in these three endosymbioses. The existence of this core set of genes is in accordance with the proposed recycling of ancient AM genes for new functions related to nodulation in legumes and actinorhizal plants.

  10. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes.

    Science.gov (United States)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai; Tian, Chunjie; Liu, Shengqun; Xu, Hongwen; Zhu, Xiancan

    2014-01-01

    The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

  11. Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes

    Directory of Open Access Journals (Sweden)

    Xiaoying Chen

    2014-01-01

    Full Text Available The effect of four different arbuscular mycorrhizal fungi (AMF on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

  12. Natural attenuation in a slag heap contaminated with cadmium: The role of plants and arbuscular mycorrhizal fungi

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Chavez, M.C. [Programa de Edafologia. Colegio de Postgraduados en Ciencias Agricolas, Campus Montecillo. Carretera Mexico-Texcoco, km 36.5. Montecillo, Texcoco, Mexico, 56230 (Mexico)], E-mail: carmeng@colpos.mx; Carrillo-Gonzalez, R.; Gutierrez-Castorena, M.C. [Programa de Edafologia. Colegio de Postgraduados en Ciencias Agricolas, Campus Montecillo. Carretera Mexico-Texcoco, km 36.5. Montecillo, Texcoco, Mexico, 56230 (Mexico)

    2009-01-30

    A field study of the natural attenuation occurring in a slag heap contaminated with high available cadmium was carried out. The aims of this research were: to determine plants colonizing this slag heap; to analyze colonization and morphological biodiversity of spores of arbuscular mycorrhizal fungi (AMF); to determine spore distribution in undisturbed samples; to know mycelium and glomalin abundance in the rhizosphere of these plants, and to investigate glomalin participation in Cd-stabilization. Forming vegetal islands, 22 different pioneering plant species from 11 families were colonizing the slag heap. The most common plants were species of Fabaceae, Asteraceae and Poaceae. Almost all plants were hosting AMF in their roots, and spores belonging to Gigaspora, Glomus, Scutellospora and Acaulospora species were observed. Micromorphological analysis showed that spores were related to decomposing vegetal residues and excrements, which means that mesofauna is contributing to their dispersion in the groundmass. Mycelium mass ranged from 0.11 to 26.3 mg/g, which contained between 13 and 75 mg of glomalin/g. Slag-extracted total glomalin was between 0.36 and 4.74 mg/g. Cadmium sequestered by glomalin extracted from either slag or mycelium was 0.028 mg/g. The ecological implication of these results is that organisms occupying vegetal patches are modifying mine residues, which contribute to soil formation.

  13. Impact of weed control on arbuscular mycorrhizal fungi in a tropical agroecosystem: a long-term experiment.

    Science.gov (United States)

    Ramos-Zapata, José A; Marrufo-Zapata, Denis; Guadarrama, Patricia; Carrillo-Sánchez, Lilia; Hernández-Cuevas, Laura; Caamal-Maldonado, Arturo

    2012-11-01

    Cover crop species represent an affordable and effective weed control method in agroecosystems; nonetheless, the effect of its use on arbuscular mycorrhizal fungi (AMF) has been scantily studied. The goal of this study was to determine root colonization levels and AMF species richness in the rhizosphere of maize plants and weed species growing under different cover crop and weed control regimes in a long-term experiment. The treatment levels used were (1) cover of Mucuna deeringian (Muc), (2) "mulch" of Leucaena leucocephala (Leu), (3) "mulch" of Lysiloma latisiliquum (Lys), (4) herbicide (Her), (5) manual weeding (CD), (6) no weeding (SD), and (7) no maize and no weeding (B). A total of 18 species of AMF belonging to eight genera (Acaulospora, Ambispora, Claroideoglomus, Funneliformis, Glomus, Rhizophagus, Sclerocystis, and Scutellospora) were identified from trap cultures. Muc and Lys treatments had a positive impact on AMF species richness (11 and seven species, respectively), while Leu and B treatments on the other hand gave the lowest richness values (six species each). AMF colonization levels in roots of maize and weeds differed significantly between treatment levels. Overall, the use of cover crop species had a positive impact on AMF species richness as well as on the percentage of root colonized by AMF. These findings have important implications for the management of traditional agroecosystems and show that the use of cover crop species for weed control can result in a more diverse AMF community which should potentially increase crop production in the long run.

  14. Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

    Energy Technology Data Exchange (ETDEWEB)

    Jaderlund, Lotta; Arthurson, Veronica; Granhall, Ulf; Jansson, Janet K.

    2008-05-15

    The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; e.g. the two AM fungi react differently when interacting with the same bacteria on plants. G. intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth promoting microorganisms it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to get satisfactory plant growth benefits.

  15. Effects of arbuscular mycorrhizal fungi on leaf solutes and root absorption areas of trifoliate orange seedlings under water stress conditions

    Institute of Scientific and Technical Information of China (English)

    WU Qiangsheng; XIA Renxue

    2006-01-01

    The effects of the arbuscular mycorrhizal (AM)fungus Glomus mosseae on plant growth,leaf solutes and root absorption area of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were studied in potted culture under water stress conditions.Inoculation with G.mosseae increased plant height,stem diameter,leaf area,shoot dry weight,root dry weight and plant dry weight,when the soil water content was 20%,16% and 12%.AM inoculation also promoted the active and total absorption area of root system and absorption of phosphorus from the rhizosphere,enhanced the content of soluble sugar in leaves and roots,and reduced proline content in leaves.AM seedlings had higher plant water use efficiency and higher drought tolerance than non-AM seedlings.Effects of G.mosseae inoculation on trifoliate orange seedlings under 20% and 16% soil water content were more significant than under 12% soil water content.AM infection was severely restrained by 12% soil water content.Thus,effects of AM fungi on plants were probably positively related to the extent of root colonization by AM fungi.The mechanism of AM fungi in enhancing drought resistance of host plants ascribed to greater osmotic adjustment and greater absorption area of root system by AM colonization.

  16. Cooperation through Competition-Dynamics and Microeconomics of a Minimal Nutrient Trade System in Arbuscular Mycorrhizal Symbiosis.

    Science.gov (United States)

    Schott, Stephan; Valdebenito, Braulio; Bustos, Daniel; Gomez-Porras, Judith L; Sharma, Tripti; Dreyer, Ingo

    2016-01-01

    In arbuscular mycorrhizal (AM) symbiosis, fungi and plants exchange nutrients (sugars and phosphate, for instance) for reciprocal benefit. Until now it is not clear how this nutrient exchange system works. Here, we used computational cell biology to simulate the dynamics of a network of proton pumps and proton-coupled transporters that are upregulated during AM formation. We show that this minimal network is sufficient to describe accurately and realistically the nutrient trade system. By applying basic principles of microeconomics, we link the biophysics of transmembrane nutrient transport with the ecology of organismic interactions and straightforwardly explain macroscopic scenarios of the relations between plant and AM fungus. This computational cell biology study allows drawing far reaching hypotheses about the mechanism and the regulation of nutrient exchange and proposes that the "cooperation" between plant and fungus can be in fact the result of a competition between both for the same resources in the tiny periarbuscular space. The minimal model presented here may serve as benchmark to evaluate in future the performance of more complex models of AM nutrient exchange. As a first step toward this goal, we included SWEET sugar transporters in the model and show that their co-occurrence with proton-coupled sugar transporters results in a futile carbon cycle at the plant plasma membrane proposing that two different pathways for the same substrate should not be active at the same time.

  17. Cooperation through Competition—Dynamics and Microeconomics of a Minimal Nutrient Trade System in Arbuscular Mycorrhizal Symbiosis

    Science.gov (United States)

    Schott, Stephan; Valdebenito, Braulio; Bustos, Daniel; Gomez-Porras, Judith L.; Sharma, Tripti; Dreyer, Ingo

    2016-01-01

    In arbuscular mycorrhizal (AM) symbiosis, fungi and plants exchange nutrients (sugars and phosphate, for instance) for reciprocal benefit. Until now it is not clear how this nutrient exchange system works. Here, we used computational cell biology to simulate the dynamics of a network of proton pumps and proton-coupled transporters that are upregulated during AM formation. We show that this minimal network is sufficient to describe accurately and realistically the nutrient trade system. By applying basic principles of microeconomics, we link the biophysics of transmembrane nutrient transport with the ecology of organismic interactions and straightforwardly explain macroscopic scenarios of the relations between plant and AM fungus. This computational cell biology study allows drawing far reaching hypotheses about the mechanism and the regulation of nutrient exchange and proposes that the “cooperation” between plant and fungus can be in fact the result of a competition between both for the same resources in the tiny periarbuscular space. The minimal model presented here may serve as benchmark to evaluate in future the performance of more complex models of AM nutrient exchange. As a first step toward this goal, we included SWEET sugar transporters in the model and show that their co-occurrence with proton-coupled sugar transporters results in a futile carbon cycle at the plant plasma membrane proposing that two different pathways for the same substrate should not be active at the same time. PMID:27446142

  18. Interactive Effects of Arbuscular Mycorrhizal Fungi and Copper Stress on Flowering Phenology and Reproduction of Elsholtzia splendens.

    Directory of Open Access Journals (Sweden)

    Zexin Jin

    Full Text Available Plant responses to heavy metal contamination may depend on the presence of arbuscular mycorrhizal fungi (AMF. Elsholtzia splendens is an indicator species for the presence of copper (Cu mines because both its flowering phenology and reproduction are tolerant to heavy metals. To test whether effects of Cu on the flowering phenology and reproduction of E. splendens depend on the presence of AMF, we conducted a factorial experiment with two Cu treatments (with or without Cu addition crossed with two AMF treatments (with or without AMF inoculation. Without AMF, Cu addition significantly delayed the onset dates, ending dates and peak dates of flowering and decreased flowering duration. However, AMF inoculation reversed the effects of Cu stress, with recovered flowering onset and ending dates and increased the flowering duration. Cu addition significantly decreased inflorescence width and number, inflorescence biomass, vegetative biomass and total seed number, but significantly increased 1000-seed weight. AMF inoculation significantly increased vegetative biomass. Two-way ANOVA results showed that the interactive effects between Cu addition and AMF inoculation were significant on the inflorescence number, vegetative biomass and total seed number. These results indicate that AMF can alleviate the Cu stress on the flowering phenology and reproduction