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Sample records for arbuscular mycorrhizal fungies

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

    PubMed Central

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

    2016-01-01

    Arbuscular mycorrhizal fungi are asexual, obligately symbiotic fungi with unique morphology and genomic structure, which occupy a dual niche, that is, the soil and the host root. Consequently, the direct adoption of models for community assembly developed for other organism groups is not evident. In this paper we adapted modern coexistence and assembly theory to arbuscular mycorrhizal fungi. We review research on the elements of community assembly and coexistence of arbuscular mycorrhizal fungi, highlighting recent studies using molecular methods. By addressing several points from the individual to the community level where the application of modern community ecology terms runs into problems when arbuscular mycorrhizal fungi are concerned, we aim to account for these special circumstances from a mycocentric point of view. We suggest that hierarchical spatial structure of arbuscular mycorrhizal fungal communities should be explicitly taken into account in future studies. The conceptual framework we develop here for arbuscular mycorrhizal fungi is also adaptable for other host-associated microbial communities. PMID:27093046

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

    PubMed

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

    2016-10-01

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

  3. Epiparasitic plants specialized on arbuscular mycorrhizal fungi.

    PubMed

    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.

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

    PubMed

    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.

  5. Cover cropping impacts on arbuscular mycorrhizal fungi and soil aggregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are a management tool which can extend the period of time that a living plant is growing and conducting photosynthesis. This is critical for soil health, because most of the soil organisms, particularly the arbuscular mycorrhizal fungi, are limited by carbon. Research, on-farm, and demon...

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

    PubMed

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

    2011-01-01

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

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

    PubMed Central

    Evelin, Heikham; Kapoor, Rupam; Giri, Bhoopander

    2009-01-01

    Background Salt stress has become a major threat to plant growth and productivity. Arbuscular mycorrhizal fungi colonize plant root systems and modulate plant growth in various ways. Scope This review addresses the significance of arbuscular mycorrhiza in alleviation of salt stress and their beneficial effects on plant growth and productivity. It also focuses on recent progress in unravelling biochemical, physiological and molecular mechanisms in mycorrhizal plants to alleviate salt stress. Conclusions The role of arbuscular mycorrhizal fungi in alleviating salt stress is well documented. This paper reviews the mechanisms arbuscular mycorrhizal fungi employ to enhance the salt tolerance of host plants such as enhanced nutrient acquisition (P, N, Mg and Ca), maintenance of the K+ : Na+ ratio, biochemical changes (accumulation of proline, betaines, polyamines, carbohydrates and antioxidants), physiological changes (photosynthetic efficiency, relative permeability, water status, abscissic acid accumulation, nodulation and nitrogen fixation), molecular changes (the expression of genes: PIP, Na+/H+ antiporters, Lsnced, Lslea and LsP5CS) and ultra-structural changes. Theis review identifies certain lesser explored areas such as molecular and ultra-structural changes where further research is needed for better understanding of symbiosis with reference to salt stress for optimum usage of this technology in the field on a large scale. This review paper gives useful benchmark information for the development and prioritization of future research programmes. PMID:19815570

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

    PubMed

    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.

  9. Investigating the Endobacteria Which Thrive in Arbuscular Mycorrhizal Fungi.

    PubMed

    Desirò, Alessandro; Salvioli, Alessandra; Bonfante, Paola

    2016-01-01

    The study of the so-called unculturable bacteria is still considered a challenging task. However, given recent improvements in the sensitivity of culture-free approaches, the identification and characterization of such microbes in complex biological samples is now possible. In this chapter we report how endobacteria thriving inside arbuscular mycorrhizal fungi (AMF), which are themselves obligate biotrophs of plants, can be studied using a combination of in vitro culture, molecular biology, and microscopy techniques. PMID:26791495

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

    PubMed

    Sikes, Benjamin A

    2010-06-01

    Arbuscular mycorrhizal (AM) fungi are mainly thought to facilitate phosphorus uptake in plants, but they can also perform several other functions that are equally beneficial. Our recent study sheds light on the factors determining one such function, enhanced plant protection from root pathogens. Root infection by the fungal pathogen Fusarium oxysporum was determined by both plant susceptibility and the ability of an AM fungal partner to suppress the pathogen. The non-susceptible plant species (Allium cepa) had limited F. oxysporum infection even without AM fungi. In contrast, the susceptible plant species (Setaria glauca) was heavily infected and only AM fungi in the family Glomeraceae limited pathogen abundance. Plant susceptibility to pathogens was likely determined by contrasting root architectures between plants, with the simple rooted plant (A. cepa) presenting fewer sites for infection.AM fungal colonization, however, was not limited in the same way in part because plants with fewer, simple roots are more mycorrhizal dependent. Protection only by Glomus species also indicates that whatever the mechanism(s) of this function, it responds to AM fungal families differently. While poor at pathogen protection, AM fungal species in the family Gigasporaceae most benefited the growth of the simple rooted plant species. Our research indicates that plant trait differences, such as root architecture can determine how important each mycorrhizal function is to plant growth but the ability to provide these functions differs among AM fungi. PMID:20400855

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  13. Impacts of farm management upon arbuscular mycorrhizal fungi and production and utilization of inoculum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a mutualistic symbiosis with the roots of most crop plants. The plant benefits through increased: nutrient uptake from the soil, disease resistance, and water stress resistance. Optimal utilization of AM fungi is essen...

  14. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    PubMed Central

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  15. Increasing diveristy of arbuscular mycorrhizal fungi in agroecosystems using specific cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fall-planted cover crops provide a plant host for obligate symbiotic arbuscular mycorrhizal fungi (AMF) during otherwise fallow periods and thus may increase AMF numbers in agroecosystems. Increased AMF numbers should increase mycorrhizal colonization of the subsequent cash crops, which has been li...

  16. Quantification of the proliferation of arbuscular mycorrhizal fungi in soil

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Lilje, Osu; McGee, Peter

    2013-04-01

    Good soil structure is important for sustaining agricultural production and preserving functions of the soil ecosystem. Soil aggregation is a critically important component of soil structure. Stable aggregates enable water infiltration, gas exchange for biological activities of plant roots and microorganisms, living space and surfaces for soil microbes, and contribute to stabilization of organic matter and storage of organic carbon (OC) in soil. Soil aggregation involves fine roots, organic matter and hyphae of arbuscular mycorrhizal (AM) fungi. Hyphal proliferation is essential for soil aggregation and sequestration of OC in soil. We do not yet have a mechanism to directly quantify the density of hyphae in soil. Organic materials and available phosphorus are two of the major factors that influence fungi in soil. Organic materials are a source of energy for saprotrophic microbes. Fungal hyphae increase in the presence of organic matter. Phosphorus is an important element usually found in ecosystems. The low availability of phosphorus limits the biological activity of microbes. AM fungi benefit plants by delivering phosphorus to the root system. However, the density and the length of hyphae of AM fungi do not appear to be influenced by available phosphorus. A number of indirect methods have been used to visualize distribution of fungi in soil. Reliable analyses of soil are limited because of soil characteristics. Soils are fragile, and fragility limits opportunity for non-destructive analysis. The soil ecosystem is complex. Soil particles are dense and the density obscures the visualization of fungal hyphae. Fungal hyphae are relatively fine and information at the small scale (<250µm) is key to understanding how fungi respond to environmental stimuli. This experiment tested whether organic carbon (starch), phosphorus (K2HPO4) and their mixture influences proliferation of hyphae of AM fungi. Hyphae were quantified in an artificial soil matrix using micro

  17. Do genetically modified plants impact arbuscular mycorrhizal fungi?

    PubMed

    Liu, Wenke

    2010-02-01

    The development and use of genetically modified plants (GMPs), as well as their ecological risks have been a topic of considerable public debate since they were first released in 1996. To date, no consistent conclusions have been drawn dealing with ecological risks on soil microorganisms of GMPs for the present incompatible empirical data. Arbuscular mycorrhizal fungi (AMF), important in regulating aboveground and underground processes in ecosystems, are the most crucial soil microbial community worthy of being monitored in ecological risks assessment of GMPs for their sensitivity to environmental alterations (plant, soil, climatic factor etc.). Based on current data, we suggest that there is a temporal-spatial relevance between expression and rhizosphere secretion of anti-disease and insecticidal proteins (e.g., Bt-Bacillus thuringiensis toxins) in and outer roots, and AMF intraradical and extraradical growth and development. Therefore, taking Bt transgenic plants (BTPs) for example, Bt insecticidal proteins constitutive expression and rhizosphere release during cultivation of BTPs may damage some critical steps of the AMF symbiotic development. More important, these processes of BTPs coincide with the entire life cycle of AMF annually, which may impact the diversity of AMF after long-term cultivation period. It is proposed that interactions between GMPs and AMF should be preferentially studied as an indicator for ecological impacts of GMPs on soil microbial communities. In this review, advances in impacts of GMPs on AMF and the effect mechanisms were summarized, highlighting the possible ecological implications of interactions between GMPs and AMF in soil ecosystems.

  18. Elemental composition of arbuscular mycorrhizal fungi at high salinity.

    PubMed

    Hammer, Edith C; Nasr, Hafedh; Pallon, Jan; Olsson, Pål Axel; Wallander, Håkan

    2011-02-01

    We investigated the elemental composition of spores and hyphae of arbuscular mycorrhizal fungi (AMF) collected from two saline sites at the desert border in Tunisia, and of Glomus intraradices grown in vitro with or without addition of NaCl to the medium, by proton-induced X-ray emission. We compared the elemental composition of the field AMF to those of the soil and the associated plants. The spores and hyphae from the saline soils showed strongly elevated levels of Ca, Cl, Mg, Fe, Si, and K compared to their growth environment. In contrast, the spores of both the field-derived AMF and the in vitro grown G. intraradices contained lower or not elevated Na levels compared to their growth environment. This resulted in higher K:Na and Ca:Na ratios in spores than in soil, but lower than in the associated plants for the field AMF. The K:Na and Ca:Na ratios of G. intraradices grown in monoxenic cultures were also in the same range as those of the field AMF and did not change even when those ratios in the growth medium were lowered several orders of magnitude by adding NaCl. These results indicate that AMF can selectively take up elements such as K and Ca, which act as osmotic equivalents while they avoid uptake of toxic Na. This could make them important in the alleviation of salinity stress in their plant hosts.

  19. Soil characteristics driving arbuscular mycorrhizal fungi communities in semiarid soils

    NASA Astrophysics Data System (ADS)

    Torrecillas, Emma; del Mar Alguacil, Maria; Torres, Pilar; Díaz, Gisela; Caravaca, Fuensanta; Montesinos, Alicia; Roldán, Antonio

    2014-05-01

    Arbuscular mycorrhizal fungi (AMF) are an important soil microbial group that affects multiple ecosystems functions and processes, including nutrient cycling, plant productivity and competition, and plant diversity. We carried out a study to investigate AMF communities in the roots and the rhizosphere of Brachypodium retusum (Pers.) Beauv., a common plant species of great ecological importance that grows in different type of soils in semiarid Mediterranean areas with similar climatic conditions. We hypothesized that if both factors, host plant species and climatic conditions, cannot influence the differences in AMF communities in the roots and in the rhizosphere of Brachypodium retusum, variances in AMF richness and diversity could be due to soil characteristics. Hence we study the relationships between physical, chemical and biological soil characteristics and AMF community composition found in the roots and in the rhizospheres. We recorded sixty-seven AMF operational taxonomical units (OTUs). Each soil type presented a different AMF community composition and thus, can be characterized by its own AMF communities. A combination among some of the soil parameters could define the AMF species present in the roots and the rhizosphere of B. retusum. It was the case for calcium, urease, protease and ß-glucosidase which explained the variation in the AMF communities. In conclusion, soil charactristics can be decisive in the assembling of the AMF communities, managing the diversity and composition of these communities.

  20. Toxic effects of chlorate on three plant species inoculated with arbuscular mycorrhizal fungi.

    PubMed

    Li, Huashou; Zhang, Xiuyu; Lin, Chuxia; Wu, Qitang

    2008-11-01

    Pot experiments were conducted to examine the toxic effects of chlorate on bermudagrass, bahiagrass, and longan seedling with a focus on arbuscular mycorrhizal fungi-plant associations. The results show that application of chlorate could cause slight soil acidification, but the resulting pH was still around 5.5, which is unlikely to adversely affect plant growth. Increase in the application rate of chlorate resulted in a decrease in colonization rate of arbuscular mycorrhizal fungi in plant roots, P uptake by the plants and plant biomass. This appears to suggest that the reduction in plant growth may be related to impeded uptake of P by the plants due to the failure of the plants to form sufficient mycorrhizal associations when chlorate is in sufficient amounts to cause toxicity to arbuscular mycorrhizal fungi. Under the experimental conditions set for this study, bermudagrass suffered from stronger chlorate stress than bahiagrass and longan seedling did in terms of plant-arbuscular mycorrhizal fungi (AMF) symbiosis development.

  1. Fenpropimorph and fenhexamid impact phosphorus translocation by arbuscular mycorrhizal fungi.

    PubMed

    Zocco, Domenico; Van Aarle, Ingrid M; Oger, Elodie; Lanfranco, Luisa; Declerck, Stéphane

    2011-07-01

    Fenpropimorph and fenhexamid are sterol biosynthesis inhibitor (SBI) molecules widely used to control diseases in agriculture. Both molecules, at increasing concentrations, have been shown to impact on the non-target arbuscular mycorrhizal (AM) fungi. Root colonization, spore production and mycelium architecture, including the branched absorbing structures which are thought to be involved in phosphorus (P) uptake, were affected. In the present study, we investigated the capacity of Glomus sp. MUCL 43204 to take up, transfer and translocate labelled P to Medicago truncatula in the presence of these SBI molecules. We used a strict in vitro cultivation system associating an autotrophic plant of M. truncatula with the AM fungus. In addition, the effects of both SBI molecules on the proportion of hyphae with alkaline phosphatases (ALP), succinate dehydrogenase (SDH) activity and on the expression of the mycorrhiza-specific plant phosphate transporter MtPT4 gene were examined. We demonstrated that the two SBI molecules impacted the AM fungus. This was particularly evidenced for fenpropimorph. A decrease in P transport and ALP and SDH activities associated with the extraradical mycelium and MtPT4 expression level was noted. These three factors were closely related to the development of the AM fungus, suggesting a direct impact not only on the AM fungal growth but also on the physiology and metabolic activities of the AM fungus. These results further emphasized the interest on the autotrophic in vitro culture system as an alternative to pot experiments to investigate the mechanisms behind the impact of disease control molecules on the non-target AM fungal symbionts.

  2. Impact of arbuscular mycorrhizal fungi on maize physiology and biochemical response under variable nitrogen levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arbuscular mycorrhizal (AM) fungi are known for colonizing plant roots, transporting water and nutrients from the soil to the plant. Therefore, environmental conditions set mainly by soil water and nutrient levels are important determinants of AM function and host plant response. Mechanisms of nitro...

  3. Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A major goal of climate change research is to understand whether and how terrestrial ecosystems can sequester more carbon to mitigate rising atmospheric carbon dioxide (CO2) levels. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric CO2 has been assumed to be a major mecha...

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

    PubMed

    Asrar, Abdul-Wasea A; Elhindi, Khalid M

    2011-01-01

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

  5. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    PubMed

    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.).

  6. Mycoparasitism of arbuscular mycorrhizal fungi: a pathway for the entry of saprotrophic fungi into roots.

    PubMed

    De Jaeger, Nathalie; Declerck, Stéphane; de la Providencia, Ivan E

    2010-08-01

    Within the rhizosphere, arbuscular mycorrhizal (AM) fungi interact with a cohort of microorganisms, among which is the biological control agent, Trichoderma spp. This fungus parasitizes a wide range of phytopathogenic fungi, a phenomenon also reported in the extraradical mycelium (ERM) of AM fungi. Here, we question whether the mycoparasitism of the ERM could be extended to the intraradical mycelium (IRM), thus representing a pathway for the entry of Trichoderma harzianum within the root. Microcosm experiments allowing interactions between Glomus sp. MUCL 41833 placed in a clade that contains the recently described species Glomus irregulare and T. harzianum were set up under in vitro autotrophic culture conditions using potato as a host. A microscope camera-imaging system, coupled with succinate dehydrogenase staining, was used to assess the mycoparasitism in the ERM and IRM. Trichoderma harzianum colonized the ERM of the AM fungus and spread into the IRM, before exiting into the root cells. Intrahyphal growth of T. harzianum caused protoplasm degradation, decreasing the ERM and IRM viability. ERM of the AM fungus represented a pathway for the entry of T. harzianum into the roots of potato. It further sets off the debate on the susceptibility of the AM fungi of being infected by microorganisms from the rhizosphere. PMID:20533946

  7. Activation of Symbiosis Signaling by Arbuscular Mycorrhizal Fungi in Legumes and Rice[OPEN

    PubMed Central

    Sun, Jongho; Miller, J. Benjamin; Granqvist, Emma; Wiley-Kalil, Audrey; Gobbato, Enrico; Maillet, Fabienne; Cottaz, Sylvain; Samain, Eric; Venkateshwaran, Muthusubramanian; Fort, Sébastien; Morris, Richard J.; Ané, Jean-Michel; Dénarié, Jean; Oldroyd, Giles E.D.

    2015-01-01

    Establishment of arbuscular mycorrhizal interactions involves plant recognition of diffusible signals from the fungus, including lipochitooligosaccharides (LCOs) and chitooligosaccharides (COs). Nitrogen-fixing rhizobial bacteria that associate with leguminous plants also signal to their hosts via LCOs, the so-called Nod factors. Here, we have assessed the induction of symbiotic signaling by the arbuscular mycorrhizal (Myc) fungal-produced LCOs and COs in legumes and rice (Oryza sativa). We show that Myc-LCOs and tetra-acetyl chitotetraose (CO4) activate the common symbiosis signaling pathway, with resultant calcium oscillations in root epidermal cells of Medicago truncatula and Lotus japonicus. The nature of the calcium oscillations is similar for LCOs produced by rhizobial bacteria and by mycorrhizal fungi; however, Myc-LCOs activate distinct gene expression. Calcium oscillations were activated in rice atrichoblasts by CO4, but not the Myc-LCOs, whereas a mix of CO4 and Myc-LCOs activated calcium oscillations in rice trichoblasts. In contrast, stimulation of lateral root emergence occurred following treatment with Myc-LCOs, but not CO4, in M. truncatula, whereas both Myc-LCOs and CO4 were active in rice. Our work indicates that legumes and non-legumes differ in their perception of Myc-LCO and CO signals, suggesting that different plant species respond to different components in the mix of signals produced by arbuscular mycorrhizal fungi. PMID:25724637

  8. Carbon cycling by arbuscular mycorrhizal fungi in soil-plant systems.

    SciTech Connect

    Zhu, Y.-G.; Miller, R. M.; Environmental Research; Chinese Academy of Sciences

    2003-09-01

    Arbuscular mycorrhizal fungi (AMF) play an important role in regulating carbon fluxes between the biosphere and the atmosphere. A recent study showed that live hyphae can turn over rapidly, in five to six days on average, suggesting that carbon flow to AMF hyphae might be respired back to the atmosphere quickly. However, that study gives a limited view of the residence time of AMF hyphae in soils. AMF hyphae can also contribute to soil carbon storage through other mechanisms.

  9. Arbuscular mycorrhizal fungi (AMF) improved growth and nutritional quality of greenhouse-grown lettuce.

    PubMed

    Baslam, Marouane; Garmendia, Idoia; Goicoechea, Nieves

    2011-05-25

    Lettuce can be associated with arbuscular mycorrhizal fungi (AMF). This symbiosis involves a molecular dialogue between fungus and plant that includes the activation of antioxidant, phenylpropanoid, or carotenoid pathways. The objective of this study was to test if the association of lettuce with AMF benefited plant growth and increased the contents of compounds potentially beneficial for human health. Results showed that AMF improved growth of lettuce, thus producing a dilution effect on the concentrations of some mineral nutrients (e.g., Ca and Mn). However, Cu, Fe, anthocyanins, carotenoids, and, to a lesser extent, phenolics appeared in higher concentrations (on a wet basis) in mycorrhizal than in nonmycorrhizal plants.

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

    PubMed

    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. PMID:22939950

  11. The arbuscular mycorrhizal fungi colonising roots and root nodules of New Zealand kauri Agathis australis.

    PubMed

    Padamsee, Mahajabeen; Johansen, Renee B; Stuckey, S Alexander; Williams, Stephen E; Hooker, John E; Burns, Bruce R; Bellgard, Stanley E

    2016-05-01

    As the only endemic member in New Zealand of the ancient conifer family, Araucariaceae, Agathis australis is an ideal species to study putatively long-evolved mycorrhizal symbioses. However, little is known about A. australis root and nodular arbuscular mycorrhizal fungi (AMF), and how mycorrhizal colonisation occurs. We used light, scanning and transmission electron microscopy to characterise colonisation, and 454-sequencing to identify the AMF associated with A. australis roots and nodules. We interpreted the results in terms of the edaphic characteristics of the A. australis-influenced ecosystem. Representatives of five families of Glomeromycota were identified via high-throughput pyrosequencing. Imaging studies showed that there is abundant, but not ubiquitous, colonisation of nodules, which suggests that nodules are mostly colonised by horizontal transmission. Roots were also found to harbour AMF. This study is the first to demonstrate the multiple Glomeromycota lineages associated with A. australis including some that may not have been previously detected. PMID:27109376

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

    PubMed

    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. PMID:25841208

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

    PubMed Central

    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

  14. Stressed out symbiotes: hypotheses for the influence of abiotic stress on arbuscular mycorrhizal fungi.

    PubMed

    Millar, Niall S; Bennett, Alison E

    2016-11-01

    Abiotic stress is a widespread threat to both plant and soil communities. Arbuscular mycorrhizal (AM) fungi can alleviate effects of abiotic stress by improving host plant stress tolerance, but the direct effects of abiotic stress on AM fungi are less well understood. We propose two hypotheses predicting how AM fungi will respond to abiotic stress. The stress exclusion hypothesis predicts that AM fungal abundance and diversity will decrease with persistent abiotic stress. The mycorrhizal stress adaptation hypothesis predicts that AM fungi will evolve in response to abiotic stress to maintain their fitness. We conclude that abiotic stress can have effects on AM fungi independent of the effects on the host plant. AM fungal communities will change in composition in response to abiotic stress, which may mean the loss of important individual species. This could alter feedbacks to the plant community and beyond. AM fungi will adapt to abiotic stress independent of their host plant. The adaptation of AM fungi to abiotic stress should allow the maintenance of the plant-AM fungal mutualism in the face of changing climates.

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

    PubMed

    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.

  16. Effects of arbuscular mycorrhizal fungi inoculation on arsenic accumulation by tobacco (Nicotiana tabacum L.).

    PubMed

    Hua, Jianfeng; Lin, Xiangui; Yin, Rui; Jiang, Qian; Shao, Yufang

    2009-01-01

    A pot experiment was conducted to study the effects of arbuscular mycorrhizal (AM) fungi (from contaminated or uncontaminated soils) on arsenic (As) uptake of tobacco (Nicotiana tabacum L.) in As-contaminated soil. Mycorrhizal colonization rate, dry weight, As and P uptake by plants, concentrations of water-extractable As and As fractions were determined. A low mycorrhizal colonization rate (< 25%) was detected. Our research indicated that AM fungi isolated from polluted soils were no more effective than those from unpolluted soils when grown in symbiosis with tobacco. No significant differences were observed in roots and stalks dry weights among all treatments. Leaves and total plant dry weights were much higher in Glomus versiforme treatment than that in control treatment. As contents in roots and stalks from mycorrhizal treatments were much lower than that from control treatment. Total plant As content exhibited the same trend. P concentrations in tobacco were not affected by colonization, nor were stalks, leaves and total plant P contents. Roots P contents were remarkably lower in HN treatments than in other treatments. Meanwhile, decreased soil pH and lower water-extractable As concentrations and higher levels of As fraction bound to well-crystallized hydrous oxides of Fe and Al were found in mycorrhizal treatments than in controls. The protective effect of mycorrhiza against plant As uptake may be associated with changes in As solubility mediated by changing soil pH. These results indicated that under As stress, proper mechanisms employed by AM fungi can protect tobacco against As uptake. Results confirmed that AM fungi can play an important role in food quality and safety. PMID:19999968

  17. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    PubMed

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

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

    PubMed

    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.

  19. Increased Sporulation of Vesicular-Arbuscular Mycorrhizal Fungi by Manipulation of Nutrient Regimens †

    PubMed Central

    Douds, David D.; Schenck, N. C.

    1990-01-01

    Adjustment of pot culture nutrient solutions increased root colonization and sporulation of vesicular-arbuscular mycorrhizal (VAM) fungi. Paspalum notatum Flugge and VAM fungi were grown in a sandy soil low in N and available P. Hoagland nutrient solution without P enhanced sporulation in soil and root colonization of Acaulospora longula, Scutellospora heterogama, Gigaspora margarita, and a wide range of other VAM fungi over levels produced by a tap water control or nutrient solutions containing P. However, Glomus intraradices produced significantly more spores in plant roots in the tap water control treatment. The effect of the nutrient solutions was not due solely to N nutrition, because the addition of NH4NO3 decreased both colonization and sporulation by G. margarita relative to levels produced by Hoagland solution without P. PMID:16348115

  20. Responses of Guava Plants to Inoculation with Arbuscular Mycorrhizal Fungi in Soil Infested with Meloidogyne enterolobii.

    PubMed

    Campos, Maryluce Albuquerque da Silva; da Silva, Fábio Sérgio Barbosa; Yano-Melo, Adriana Mayumi; de Melo, Natoniel Franklin; Pedrosa, Elvira Maria Régis; Maia, Leonor Costa

    2013-09-01

    In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, CO2 evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and CO2 evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction. PMID:25288951

  1. Responses of Guava Plants to Inoculation with Arbuscular Mycorrhizal Fungi in Soil Infested with Meloidogyne enterolobii

    PubMed Central

    Campos, Maryluce Albuquerque da Silva; da Silva, Fábio Sérgio Barbosa; Yano-Melo, Adriana Mayumi; de Melo, Natoniel Franklin; Pedrosa, Elvira Maria Régis; Maia, Leonor Costa

    2013-01-01

    In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, CO2 evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and CO2 evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction. PMID:25288951

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

    PubMed

    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.

  3. Plant species differ in their ability to reduce allocation to non-beneficial arbuscular mycorrhizal fungi.

    PubMed

    Grman, Emily

    2012-04-01

    Theory suggests that cheaters threaten the persistence of mutualisms, but that sanctions to prevent cheating can stabilize mutualisms. In the arbuscular mycorrhizal symbiosis, reports of parasitism suggest that reductions in plant carbon allocation are not universally effective. I asked whether plant species differences in mycorrhizal responsiveness would affect both their susceptibility to parasitism and their reduction in allocation to non-beneficial arbuscular mycorrhizal fungi (AMF) in high-phosphorus soils. In a greenhouse experiment, I found that two C3 grasses, Bromus inermis and Elymus repens, effectively suppressed root colonization and AMF hyphal abundance. Increases in soil phosphorus did not reduce the degree to which AMF increased plant biomass. In contrast, two C4 grasses, Andropogon gerardii and Schizachyrium scoparium, more weakly reduced root colonization and failed to suppress AMF hyphal abundance. Consequently, they experienced strong declines in their response to AMF, and one species suffered parasitism. Thus, species differ in susceptibility to parasitism and their reduction in allocation to non-beneficial AMF. These differences may affect the distribution and abundance of plants and AMF, as well as the stability of the mutualism.

  4. Arbuscular mycorrhizal fungi promote the growth of Ceratocarpus arenarius (Chenopodiaceae) with no enhancement of phosphorus nutrition.

    PubMed

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

    2012-01-01

    The mycorrhizal status of plants in the Chenopodiaceae is not well studied with a few controversial reports. This study examined arbuscular mycorrhizal (AM) colonization and growth response of Ceratocarpus arenarius in the field and a greenhouse inoculation trial. The colonization rate of AM fungi in C. arenarius in in-growth field cores was low (around 15%). Vesicles and intraradical hyphae were present during all growth stages, but no arbuscules were observed. Sequencing analysis of the large ribosomal rDNA subunit detected four culturable Glomus species, G. intraradices, G. mosseae, G. etunicatum and G. microaggregatum together with eight unculturable species belong to the Glomeromycota in the root system of C. arenarius collected from the field. These results establish the mycotrophic status of C. arenarius. Both in the field and in the greenhouse inoculation trial, the growth of C. arenarius was stimulated by the indigenous AM fungal community and the inoculated AM fungal isolates, respectively, but the P uptake and concentration of the mycorrhizal plants did not increase significantly over the controls in both experiments. Furthermore, the AM fungi significantly increased seed production. Our results suggest that an alternative reciprocal benefit to carbon-phosphorus trade-off between AM fungi and the chenopod plant might exist in the extremely arid environment.

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

    PubMed Central

    Bai, Dengsha; Chen, Yinglong; Feng, Gu

    2012-01-01

    The mycorrhizal status of plants in the Chenopodiaceae is not well studied with a few controversial reports. This study examined arbuscular mycorrhizal (AM) colonization and growth response of Ceratocarpus arenarius in the field and a greenhouse inoculation trial. The colonization rate of AM fungi in C. arenarius in in-growth field cores was low (around 15%). Vesicles and intraradical hyphae were present during all growth stages, but no arbuscules were observed. Sequencing analysis of the large ribosomal rDNA subunit detected four culturable Glomus species, G. intraradices, G. mosseae, G. etunicatum and G. microaggregatum together with eight unculturable species belong to the Glomeromycota in the root system of C. arenarius collected from the field. These results establish the mycotrophic status of C. arenarius. Both in the field and in the greenhouse inoculation trial, the growth of C. arenarius was stimulated by the indigenous AM fungal community and the inoculated AM fungal isolates, respectively, but the P uptake and concentration of the mycorrhizal plants did not increase significantly over the controls in both experiments. Furthermore, the AM fungi significantly increased seed production. Our results suggest that an alternative reciprocal benefit to carbon-phosphorus trade-off between AM fungi and the chenopod plant might exist in the extremely arid environment. PMID:22957011

  6. Caesium inhibits the colonization of Medicago truncatula by arbuscular mycorrhizal fungi.

    PubMed

    Wiesel, Lea; Dubchak, Sergiy; Turnau, Katarzyna; Broadley, Martin R; White, Philip J

    2015-03-01

    Contamination of soils with radioisotopes of caesium (Cs) is of concern because of their emissions of harmful β and γ radiation. Radiocaesium enters the food chain through vegetation and the intake of Cs can affect the health of organisms. Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with plants through colonization of the roots and previous studies on the influence of AM on Cs concentrations in plants have given inconsistent results. These studies did not investigate the influence of Cs on AM fungi and it is therefore not known if Cs has a direct effect on AM colonization. Here, we investigated whether Cs influences AM colonization and if this effect impacts on the influence of Rhizophagus intraradices on Cs accumulation by Medicago truncatula. M. truncatula was grown with or without R. intraradices in pots containing different concentrations of Cs. Here, we present the first evidence that colonization of plants by AM fungi can be negatively affected by increasing Cs concentrations in the soil. Mycorrhizal colonization had little effect on root or shoot Cs concentrations. In conclusion, the colonization by AM fungi is impaired by high Cs concentrations and this direct effect of soil Cs on AM colonization might explain the inconsistent results reported in literature that have shown increased, decreased or unaffected Cs concentrations in AM plants.

  7. [Change of arbuscular mycorrhizal fungi community in response to elevational gradients on the Tibetan Plateau, China].

    PubMed

    Cai, Xiao-bu; Peng, Yue-lin

    2015-09-01

    The community structure of arbuscular mycorrhizal fungi (AMF) and mycorrhizal infection in the main herbaceous plants were studied along the elevational gradients on the Tibetan Plateau, and AMF community was characterized based on spore morphology. Community of AMF at lower elevations (2200-3400 m) in southeast Tibetan Plateau included 11 genera, covering 31 species, whereas AMF at intermediate elevations (3400-3900 m) in central Tibet included 11 genera, covering 20 species, and that at higher elevations (4300-5300 m) in northern Tibet included 6 genera, covering 14 species. With the increase of elevation, both spore density (r = 0.978, P <0.01) and species abundance (r = 0.462, P > 0.05) tended to increase. The proportion of dominant species and endemic species increased substantially, while the Shannon index (r = -0.945, P < 0.01) decreased significantly. There was no significant difference in Sorensen index (0.526-0.592) among different altitudes. Mycorrhizal infection at intermediate elevations was significantly higher than that at lower elevations or higher elevations, while the latter two did not differ significantly. Within an altitude range, elevation had significant influence on AMF community and mycorrhizal infection, and the effect differed among the three elevational sites. The results demonstrated that AMF community on the Tibetan Plateau tends to be habitat specific. The water and thermal environment as well as soil environment are the driving forces for shaping AMF community assemblages. PMID:26785564

  8. Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil

    PubMed Central

    Ambrosini, Vítor Gabriel; Voges, Joana Gerent; Canton, Ludiana; Couto, Rafael da Rosa; Ferreira, Paulo Ademar Avelar; Comin, Jucinei José; de Melo, George Wellington Bastos; Brunetto, Gustavo; Soares, Cláudio Roberto Fonsêca Sousa

    2015-01-01

    Abstract High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis) and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM), height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels. PMID:26691462

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

    PubMed

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

    2013-11-01

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

  10. Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil.

    PubMed

    Ambrosini, Vítor Gabriel; Voges, Joana Gerent; Canton, Ludiana; Couto, Rafael da Rosa; Ferreira, Paulo Ademar Avelar; Comin, Jucinei José; de Melo, George Wellington Bastos; Brunetto, Gustavo; Soares, Cláudio Roberto Fonsêca Sousa

    2015-01-01

    High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis) and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM), height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels.

  11. [Change of arbuscular mycorrhizal fungi community in response to elevational gradients on the Tibetan Plateau, China].

    PubMed

    Cai, Xiao-bu; Peng, Yue-lin

    2015-09-01

    The community structure of arbuscular mycorrhizal fungi (AMF) and mycorrhizal infection in the main herbaceous plants were studied along the elevational gradients on the Tibetan Plateau, and AMF community was characterized based on spore morphology. Community of AMF at lower elevations (2200-3400 m) in southeast Tibetan Plateau included 11 genera, covering 31 species, whereas AMF at intermediate elevations (3400-3900 m) in central Tibet included 11 genera, covering 20 species, and that at higher elevations (4300-5300 m) in northern Tibet included 6 genera, covering 14 species. With the increase of elevation, both spore density (r = 0.978, P <0.01) and species abundance (r = 0.462, P > 0.05) tended to increase. The proportion of dominant species and endemic species increased substantially, while the Shannon index (r = -0.945, P < 0.01) decreased significantly. There was no significant difference in Sorensen index (0.526-0.592) among different altitudes. Mycorrhizal infection at intermediate elevations was significantly higher than that at lower elevations or higher elevations, while the latter two did not differ significantly. Within an altitude range, elevation had significant influence on AMF community and mycorrhizal infection, and the effect differed among the three elevational sites. The results demonstrated that AMF community on the Tibetan Plateau tends to be habitat specific. The water and thermal environment as well as soil environment are the driving forces for shaping AMF community assemblages.

  12. Interactions between indigenous arbuscular mycorrhizal fungi and Aphanomyces euteiches in field-grown pea.

    PubMed

    Bødker, Lars; Kjøller, Rasmus; Kristensen, Kristian; Rosendahl, Søren

    2002-02-01

    This is the first reported study of the interactions between indigenous arbuscular mycorrhizal fungi (AMF) and Aphanomyces euteiches in pea under field conditions. A. euteiches was applied to the soil by adding oospores produced in vitro. Attempts were made to create a non-mycorrhizal control by incorporating carbendazim (Derosal Fl) in the topsoil before sowing. However, all carbendazim-treated plants showed approximately 20% root colonisation with AMF. Pea plants not treated with carbendazim showed a wide variation in AMF colonisation of 35-70% at the full flowering stage. In these control plots, root length infected with oospores of A. euteiches and colonisation by AMF were negatively correlated. Application of carbendazim increased the percent root length infected with oospores by 50-70%, depending on inoculum density of A. euteiches. Despite the lower levels of AMF colonisation in these treated plots, a negative correlation with oospore-containing root length was still observed. No correlation was found between AMF colonisation and disease severity, disease incidence or pathogen enzymatic activity (glucose-6-phosphate dehydrogenase). Thus, AMF do not seem to influence the vegetative stage of pathogen development during which cortical root rotting takes place, but rather the reproductive stage when oospores are produced. The results of this study underline the importance of field experiments for validating the significance of mycorrhizal fungi for plant health.

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

    PubMed

    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.

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

    PubMed

    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. PMID:27062807

  15. Induction of defense responses in common bean plants by arbuscular mycorrhizal fungi.

    PubMed

    Abdel-Fattah, G M; El-Haddad, S A; Hafez, E E; Rashad, Y M

    2011-05-20

    Interaction between arbuscular mycorrhizal fungi as a bio-agent and Rhizoctonia root rot disease of common bean plant was investigated in this study under natural conditions in pot experiment. A mixture of Egyptian formulated AM (Multi-VAM) in suspension form (1 × 10(6) unit L(-1) in concentration) was used at dilution of 5 ml L(-1) water. The results demonstrated that colonization of bean plants with AM fungi significantly increased growth parameters, yield parameters and mineral nutrient concentrations and reduced the negative effects on these parameters as well as both disease severity and disease incidence. Different physical and biochemical mechanisms have been shown to play a role in enhancement of plant resistance against Rhizoctonia solani, namely, improved plant nutrition, improved plant growth, increase in cell wall thickening, cytoplasmic granulation, and accumulation of some antimicrobial substances (phenolic compounds and defense related enzymes).

  16. An evidence-based consensus for the classification of arbuscular mycorrhizal fungi (Glomeromycota).

    PubMed

    Redecker, Dirk; Schüssler, Arthur; Stockinger, Herbert; Stürmer, Sidney L; Morton, Joseph B; Walker, Christopher

    2013-10-01

    The publication of a large number of taxon names at all levels within the arbuscular mycorrhizal fungi (Glomeromycota) has resulted in conflicting systematic schemes and generated considerable confusion among biologists working with these important plant symbionts. A group of biologists with more than a century of collective experience in the systematics of Glomeromycota examined all available molecular-phylogenetic evidence within the framework of phylogenetic hypotheses, incorporating morphological characters when they were congruent. This study is the outcome, wherein the classification of Glomeromycota is revised by rejecting some new names on the grounds that they are founded in error and by synonymizing others that, while validly published, are not evidence-based. The proposed "consensus" will provide a framework for additional original research aimed at clarifying the evolutionary history of this important group of symbiotic fungi. PMID:23558516

  17. [Effects of agricultural practices on community structure of arbuscular mycorrhizal fungi in agricultural ecosystem: a review].

    PubMed

    Sheng, Ping-Ping; Li, Min; Liu, Run-Jin

    2011-06-01

    Arbuscular mycorrhizal (AM) fungi are rich in diversity in agricultural ecosystem, playing a vital role based on their unique community structure. Host plants and environmental factors have important effects on AM fungal community structure, so do the agricultural practices which deserve to pay attention to. This paper summarized the research advances in the effects of agricultural practices such as irrigation, fertilization, crop rotation, intercropping, tillage, and pesticide application on AM fungal community structure, analyzed the related possible mechanisms, discussed the possible ways in improving AM fungal community structure in agricultural ecosystem, and put forward a set of countermeasures, i.e., improving fertilization system and related integrated techniques, increasing plant diversity in agricultural ecosystem, and inoculating AM fungi, to enhance the AM fungal diversity in agricultural ecosystem. The existing problems in current agricultural practices and further research directions were also proposed.

  18. An evidence-based consensus for the classification of arbuscular mycorrhizal fungi (Glomeromycota).

    PubMed

    Redecker, Dirk; Schüssler, Arthur; Stockinger, Herbert; Stürmer, Sidney L; Morton, Joseph B; Walker, Christopher

    2013-10-01

    The publication of a large number of taxon names at all levels within the arbuscular mycorrhizal fungi (Glomeromycota) has resulted in conflicting systematic schemes and generated considerable confusion among biologists working with these important plant symbionts. A group of biologists with more than a century of collective experience in the systematics of Glomeromycota examined all available molecular-phylogenetic evidence within the framework of phylogenetic hypotheses, incorporating morphological characters when they were congruent. This study is the outcome, wherein the classification of Glomeromycota is revised by rejecting some new names on the grounds that they are founded in error and by synonymizing others that, while validly published, are not evidence-based. The proposed "consensus" will provide a framework for additional original research aimed at clarifying the evolutionary history of this important group of symbiotic fungi.

  19. The impact of arbuscular mycorrhizal fungi on plant growth following herbivory: A search for pattern

    NASA Astrophysics Data System (ADS)

    Borowicz, Victoria A.

    2013-10-01

    Arbuscular mycorrhizal (AM) fungi can facilitate nutrient uptake and increase host plant growth but also place constraints on the host's carbon budget. When plants are stressed by herbivory the net effect of the symbiosis may be altered tolerance. Individual experiments manipulating AM fungi and herbivory have demonstrated increased, decreased, and no effect on tolerance but patterns with respect to plant, herbivore, or fungus characteristics have not emerged. Meta-analysis of published results from factorial experiments was used to describe the size of the effects of herbivory and of AM fungi on host growth when factors such as cause of damage, inoculum, and host characteristics are considered, and to determine whether AM fungi alter the effects of herbivory. Also, the correlation between the effect of AM fungi on tolerance and resistance was tested with data from studies that examined insect performance. Herbivory strongly and consistently reduced shoot and root growth, especially in perennial plants and crops. AM fungi increased shoot growth of perennials but not annuals, and when insects caused damage but not when artificial defoliation was applied. Root growth was consistently greater with AM fungi. The interaction of AM fungi and herbivory, which indicates whether AM fungi alter the effects of herbivory, was variable and never significant overall but homogeneity tests indicated underlying structure. In experiments that used single species inoculum, Glomus intraradices increased, whereas Glomus mosseae reduced, effects of herbivory on shoot growth. Multispecies inocula magnified effects of herbivory on root growth whereas single species inocula ameliorated effects. The impact of AM fungi on resistance to herbivory was positively correlated with the impact on tolerance; however AM fungi reduced both tolerance and resistance in many cases. Review of these results with respect to the types of systems studied suggests directions for future investigation.

  20. Diversity of Rhizosphere Soil Arbuscular Mycorrhizal Fungi in Various Soybean Cultivars under Different Continuous Cropping Regimes

    PubMed Central

    Jie, Weiguang; Liu, Xiaorui; Cai, Baiyan

    2013-01-01

    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. PMID:23977368

  1. Xyloglucanases in the interaction between saprobe fungi and the arbuscular mycorrhizal fungus Glomus mosseae.

    PubMed

    Aranda, Elisabet; Sampedro, Inmaculada; Díaz, Rosario; García, Mercedes; Ocampo, Juan Antonio; García-Romera, Inmaculada

    2007-08-01

    We studied the production of xyloglucanase enzymes of pea and lettuce roots in the presence of saprobe and arbuscular mycorrhizal (AM) fungi. The AM fungus Glomus mosseae and the saprobe fungi Fusarium graminearum, Fusarium oxysporum-126, Trichoderma harzianum, Penicillium chrysogenum, Pleurotus ostreatus and Aspergillus niger were used. G. mosseae increased the shoot and root dry weight of pea but not of lettuce. Most of the saprobe fungi increased the level of mycorrhization of pea and lettuce, but only P. chrysogenum and T. harzianum inoculated together with G. mosseae increased the dry weight of pea and lettuce respectively. The AM and saprobe fungi increased the production of xyloglucanases by plant roots. The level of xyloglucanase activities and the number of xyloglucanolytic isozymes in plants inoculated with G. mosseae and most of the saprobe fungi tested were higher than when both microorganisms were inoculated separately. The possible relationship between xylogucanase activities and the ability of AM and saprobe fungi to improve the dry weight and AM root colonization of plants was discussed.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27435342

  3. Establishment and effectiveness of inoculated arbuscular mycorrhizal fungi in agricultural soils.

    PubMed

    Köhl, Luise; Lukasiewicz, Catherine E; van der Heijden, Marcel G A

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are promoted as biofertilizers for sustainable agriculture. So far, most researchers have investigated the effects of AMF on plant growth under highly controlled conditions with sterilized soil, soil substrates or soils with low available P or low inoculum potential. However, it is still poorly documented whether inoculated AMF can successfully establish in field soils with native AMF communities and enhance plant growth. We inoculated grassland microcosms planted with a grass-clover mixture (Lolium multiflorum and Trifolium pratense) with the arbuscular mycorrhizal fungus Rhizoglomus irregulare. The microcosms were filled with eight different unsterilized field soils that varied greatly in soil type and chemical characteristics and indigenous AMF communities. We tested whether inoculation with AMF enhanced plant biomass and R. irregulare abundance using a species specific qPCR. Inoculation increased the abundance of R. irregulare in all soils, irrespective of soil P availability, the initial abundance of R. irregulare or the abundance of native AM fungal communities. AMF inoculation had no effect on the grass but significantly enhanced clover yield in five out of eight field soils. The results demonstrate that AMF inoculation can be successful, even when soil P availability is high and native AMF communities are abundant.

  4. Prospects for arbuscular mycorrhizal fungi (AMF) to assist in phytoremediation of soil hydrocarbon contaminants.

    PubMed

    Rajtor, Monika; Piotrowska-Seget, Zofia

    2016-11-01

    Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with the roots of 80-90% of vascular plant species and may constitute up to 50% of the total soil microbial biomass. AMF have been considered to be a tool to enhance phytoremediation, as their mycelium create a widespread underground network that acts as a bridge between plant roots, soil and rhizosphere microorganisms. Abundant extramatrical hyphae extend the rhizosphere thus creating the hyphosphere, which significantly increases the area of a plant's access to nutrients and contaminants. The paper presents and evaluates the role and significance of AMF in phytoremediation of hydrocarbon contaminated sites. We focused on (1) an impact of hydrocarbons on arbuscular mycorrhizal symbiosis, (2) a potential of AMF to enhance phytoremediation, (3) determinants that influence effectiveness of hydrocarbon removal from contaminated soils. This knowledge may be useful for selection of proper plant and fungal symbionts and crucial to optimize environmental conditions for effective AMF-mediated phytoremediation. It has been concluded that three-component phytoremediation systems based on synergistic interactions between plant roots, AMF and hydrocarbon-degrading microorganisms demonstrated high effectiveness in dissipation of organic pollutants in soil.

  5. Prospects for arbuscular mycorrhizal fungi (AMF) to assist in phytoremediation of soil hydrocarbon contaminants.

    PubMed

    Rajtor, Monika; Piotrowska-Seget, Zofia

    2016-11-01

    Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with the roots of 80-90% of vascular plant species and may constitute up to 50% of the total soil microbial biomass. AMF have been considered to be a tool to enhance phytoremediation, as their mycelium create a widespread underground network that acts as a bridge between plant roots, soil and rhizosphere microorganisms. Abundant extramatrical hyphae extend the rhizosphere thus creating the hyphosphere, which significantly increases the area of a plant's access to nutrients and contaminants. The paper presents and evaluates the role and significance of AMF in phytoremediation of hydrocarbon contaminated sites. We focused on (1) an impact of hydrocarbons on arbuscular mycorrhizal symbiosis, (2) a potential of AMF to enhance phytoremediation, (3) determinants that influence effectiveness of hydrocarbon removal from contaminated soils. This knowledge may be useful for selection of proper plant and fungal symbionts and crucial to optimize environmental conditions for effective AMF-mediated phytoremediation. It has been concluded that three-component phytoremediation systems based on synergistic interactions between plant roots, AMF and hydrocarbon-degrading microorganisms demonstrated high effectiveness in dissipation of organic pollutants in soil. PMID:27487095

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2016-01-01

    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. PMID:27435342

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

    PubMed

    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.

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

    PubMed

    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. PMID:27180108

  10. Complementarity in nutrient foraging strategies of absorptive fine roots and arbuscular mycorrhizal fungi across 14 coexisting subtropical tree species.

    PubMed

    Liu, Bitao; Li, Hongbo; Zhu, Biao; Koide, Roger T; Eissenstat, David M; Guo, Dali

    2015-10-01

    In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrhizal fungi across these two types of root system remains unclear. We measured traits related to nutrient foraging (root morphology, architecture and proliferation, AM colonization and extramatrical hyphal length) across 14 coexisting AM subtropical tree species following root pruning and nutrient addition treatments. After root pruning, species with thinner roots showed more root growth, but lower mycorrhizal colonization, than species with thicker roots. Under multi-nutrient (NPK) addition, root growth increased, but mycorrhizal colonization decreased significantly, whereas no significant changes were found under nitrogen or phosphate additions. Moreover, root length proliferation was mainly achieved by altering root architecture, but not root morphology. Thin-root species seem to forage nutrients mainly via roots, whereas thick-root species rely more on mycorrhizal fungi. In addition, the reliance on mycorrhizal fungi was reduced by nutrient additions across all species. These findings highlight complementary strategies for nutrient foraging across coexisting species with contrasting root traits.

  11. Impact of arbuscular mycorrhizal fungi on the allergenic potential of tomato.

    PubMed

    Schwarz, Dietmar; Welter, Saskia; George, Eckhard; Franken, Philipp; Lehmann, Karola; Weckwerth, Wolfram; Dölle, Sabine; Worm, Margitta

    2011-07-01

    Arbuscular mycorrhizal (AM) fungi influence the expression of defence-related genes in roots and can cause systemic resistance in plants probably due to the induced expression of specific defence proteins. Among the different groups of defence proteins, plant food allergens were identified. We hypothesized that tomato-allergic patients differently react to tomatoes derived from plants inoculated or not by mycorrhizal fungi. To test this, two tomato genotypes, wild-type 76R and a nearly isogenic mycorrhizal mutant RMC, were inoculated with the AM fungus Glomus mosseae or not under conditions similar to horticultural practice. Under such conditions, the AM fungus showed only a very low colonisation rate, but still was able to increase shoot growth of the wild-type 76R. Nearly no colonisation was observed in the mutant RMC, and shoot development was also not affected. Root fresh weights were diminished in AM-inoculated plants of both genotypes compared to the corresponding controls. No mycorrhizal effects were observed on the biomass and the concentration of phosphate and nitrogen in fruits. Real-time quantitative polymerase chain reaction analysis revealed that six among eight genes encoding for putative allergens showed a significant induced RNA accumulation in fruits of AM-colonised plants. However, human skin reactivity tests using mixed samples of tomato fruits from the AM-inoculated and control plants showed no differences. Our data indicate that AM colonisation under conditions close to horticultural practice can induce the expression of allergen-encoding genes in fruits, but this does not lead necessarily to a higher allergenic potential.

  12. Evidence for functional redundancy in arbuscular mycorrhizal fungi and implications for agroecosystem management.

    PubMed

    Gosling, Paul; Jones, Julie; Bending, Gary D

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi provide benefits to host plants and show functional diversity, with evidence of functional trait conservation at the family level. Diverse communities of AM fungi ought therefore to provide increased benefits to the host, with implications for the management of sustainable agroecosystems. However, this is often not evident in the literature, with diversity saturation at low species number. Growth and nutrient uptake were measured in onions in the glasshouse on AM-free phosphorus (P)-poor soil, inoculated with between one and seven species of AM fungi in all possible combinations. Inoculation with AM fungi increased shoot dry weight as well as P and copper concentrations in shoots but reduced the concentration of potassium and sulphur. There was little evidence of increased benefit from high AM fungal diversity, and increasing diversity beyond three species did not result in significantly higher shoot weight or P or Cu concentrations. Species of Glomeraceae had the greatest impact on growth and nutrient uptake, while species of Acaulospora and Racocetra did not have a significant impact. Failure to show a benefit from high AM fungal diversity in this and other studies may be the result of experimental conditions, with the benefits of AM fungal diversity only becoming apparent when the host plant is faced with multiple stress factors. Replicating the complex interactions between AM fungi, the host plant and their environment in the laboratory in order to fully understand these interactions is a major challenge to AM research.

  13. Genetic variation in the response of the weed Ruellia nudiflora (Acanthaceae) to arbuscular mycorrhizal fungi.

    PubMed

    Ramos-Zapata, José Alberto; Campos-Navarrete, María José; Parra-Tabla, Víctor; Abdala-Roberts, Luis; Navarro-Alberto, Jorge

    2010-04-01

    The main goal of this work was to test for plant genetic variation in the phenotypic plasticity response of the weed Ruellia nudiflora to arbuscular mycorrhizal (AM) fungi inoculation. We collected plants in the field, kept them under homogeneous conditions inside a nursery, and then collected seeds from these parent plants to generate five inbred lines (i.e., genetic families). Half of the plants of each inbred line were inoculated with AM fungi while the other half were not (controls); a fully crossed experimental design was then used to test for the effects of treatment (with or without AM fungi inoculation) and inbred line (genetic family). For each plant, we recorded the number of leaves produced and the number of days it survived during a 2-month period. Results showed a strong positive treatment effect (plastic response to AM fungi inoculation) for leaf production and survival. Moreover, in terms of survival, the treatment effect differed between genetic families (significant genetic family by treatment interaction). These findings indicate that the positive effect of AM fungi on plant survival (and potentially also growth) differs across plant genotypes and that such condition may contribute to R. nudiflora's capacity to colonize new environments. PMID:19862559

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

    PubMed

    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.

  15. Diversity of Arbuscular Mycorrhizal Fungi and its Influence on Soil Dynamics

    NASA Astrophysics Data System (ADS)

    Turner, K. M.; Treseder, K. K.

    2002-12-01

    The diversity of arbuscular mycorrhizal fungi (AMF) has been correlated with increased plant biodiversity, productivity, and fecundity. However, the influence of AMF diversity on below-ground ecosystem characteristics has yet to be determined. A greenhouse experiment was conducted to examine these interactions. Pot cultures containing equal numbers of four common grass species were either inoculated with one of four AMF species, a mixture of all four species, or were not inoculated, for a total of six different community compositions. After two months of growth, the pot cultures were harvested. Results indicated both individual species effects and diversity effects on factors controlling ecosystem-level processes. Bacterial abundance, bacterial diversity, glomalin concentration, hyphal colonization of roots, and above ground plant biomass exhibited significant differences among treatments. However, N mineralization rates, nitrification rates, and levels of organic matter did not respond significantly to treatments. Bacterial diversity, bacterial abundance, and above ground biomass displayed a similar pattern across treatments, and this may indicate potential interactions among AMF, bacteria, and plants. Specifically, the non-mycorrhizal treatment produced the highest values for all three of these characters while the Glomus intraradices monoculture produced the lowest values. Species also varied in production of glomalin, a compound associated with carbon sequestration, with Gigaspora gigantea producing the highest concentration of 1.67mg/g soil and Glomus etunicatumproducing the lowest concentration of 0.63 mg/g soil. Arbuscular mycorrhizal diversity significantly effected the total amount of fungal root colonization (high diversity: 70.9 percent; monocultures: 46.1-63.3 percent) and fungal fecundity and had a marginally significant influence on the abundance of external hyphae. This increased fungal abundance suggested niche complimentarity and positive species

  16. DNA-Based Characterization and Identification of Arbuscular Mycorrhizal Fungi Species.

    PubMed

    Senés-Guerrero, Carolina; Schüßler, Arthur

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of most land plants. They have great ecological and economic importance as they can improve plant nutrition, plant water supply, soil structure, and plant resistance to pathogens. We describe two approaches for the DNA-based characterization and identification of AMF, which both can be used for single fungal spores, soil, or roots samples and resolve closely related AMF species: (a) Sanger sequencing of a 1.5 kb extended rDNA-barcode from clone libraries, e.g., to characterize AMF isolates, and (b) high throughput 454 GS-FLX+ pyrosequencing of a 0.8 kb rDNA fragment, e.g., for in-field monitoring. PMID:26791499

  17. Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated CO2.

    PubMed

    Cheng, Lei; Booker, Fitzgerald L; Tu, Cong; Burkey, Kent O; Zhou, Lishi; Shew, H David; Rufty, Thomas W; Hu, Shuijin

    2012-08-31

    The extent to which terrestrial ecosystems can sequester carbon to mitigate climate change is a matter of debate. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric carbon dioxide (CO(2)) has been assumed to be a major mechanism facilitating soil carbon sequestration by increasing carbon inputs to soil and by protecting organic carbon from decomposition via aggregation. We present evidence from four independent microcosm and field experiments demonstrating that CO(2) enhancement of AMF results in considerable soil carbon losses. Our findings challenge the assumption that AMF protect against degradation of organic carbon in soil and raise questions about the current prediction of terrestrial ecosystem carbon balance under future climate-change scenarios. PMID:22936776

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

    PubMed

    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. PMID:20652364

  19. Dynamics of phoxim residues in green onion and soil as influenced by arbuscular mycorrhizal fungi.

    PubMed

    Wang, Fa Yuan; Shi, Zhao Yong; Tong, Rui Jian; Xu, Xiao Feng

    2011-01-15

    Organophosphorus pesticides in crops and soil pose a serious threat to public health and environment. Arbuscular mycorrhizal (AM) fungi may make a contribution to organophosphate degradation in soil and consequently decrease chemical residues in crops. A pot culture experiment was conducted to investigate the influences of Glomus caledonium 90036 and Acaulospora mellea ZZ on the dynamics of phoxim residues in green onion (Allium fistulosum L.) and soil at different harvest dates after phoxim application. Results show that mycorrhizal colonization rates of inoculated plants were higher than 70%. Shoot and root fresh weights did not vary with harvest dates but increased significantly in AM treatments. Phoxim residues in plants and soil decreased gradually with harvest dates, and markedly reduced in AM treatments. Kinetic analysis indicated that phoxim degradation in soil followed a first-order kinetic model. AM inoculation accelerated the degradation process and reduced the half-life. G. caledonium 90036 generally produced more pronounced effects than A. mellea ZZ on both the plant growth and phoxim residues in plants and soil. Our results indicate a promising potential of AM fungi for the control of organophosphate residues in vegetables, as well as for the phytoremediation of organophosphorus pesticide-contaminated soil.

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

    PubMed

    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.

  1. Dynamics of phoxim residues in green onion and soil as influenced by arbuscular mycorrhizal fungi.

    PubMed

    Wang, Fa Yuan; Shi, Zhao Yong; Tong, Rui Jian; Xu, Xiao Feng

    2011-01-15

    Organophosphorus pesticides in crops and soil pose a serious threat to public health and environment. Arbuscular mycorrhizal (AM) fungi may make a contribution to organophosphate degradation in soil and consequently decrease chemical residues in crops. A pot culture experiment was conducted to investigate the influences of Glomus caledonium 90036 and Acaulospora mellea ZZ on the dynamics of phoxim residues in green onion (Allium fistulosum L.) and soil at different harvest dates after phoxim application. Results show that mycorrhizal colonization rates of inoculated plants were higher than 70%. Shoot and root fresh weights did not vary with harvest dates but increased significantly in AM treatments. Phoxim residues in plants and soil decreased gradually with harvest dates, and markedly reduced in AM treatments. Kinetic analysis indicated that phoxim degradation in soil followed a first-order kinetic model. AM inoculation accelerated the degradation process and reduced the half-life. G. caledonium 90036 generally produced more pronounced effects than A. mellea ZZ on both the plant growth and phoxim residues in plants and soil. Our results indicate a promising potential of AM fungi for the control of organophosphate residues in vegetables, as well as for the phytoremediation of organophosphorus pesticide-contaminated soil. PMID:20870354

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

    PubMed

    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.

  3. 'Candidatus glomeribacter gigasporarum' gen. nov., sp. nov., an endosymbiont of arbuscular mycorrhizal fungi.

    PubMed

    Bianciotto, Valeria; Lumini, Erica; Bonfante, Paola; Vandamme, Peter

    2003-01-01

    Arbuscular mycorrhizal fungi are obligate endosymbionts that colonize the roots of almost 80 % of land plants. The present paper describes morphological and molecular data on a bacterial endosymbiont living in the cytoplasm of dormant or germinating spores and symbiotic mycelia of the fungal species Gigaspora margarita, Scutellospora persica and Scutellospora castanea. PCR amplification of almost the entire 16S rRNA gene of the Gigaspora margarita BEG 34 endosymbiont, using universal bacterial primers, and subsequent sequence analysis demonstrated that this organism occupies a very distinct phylogenetic position within the beta-Proteobacteria, with the genera Burkholderia, Pandoraea and Ralstonia as its closest neighbours. Primers specific to the 16S rDNA of the endosymbiotic bacteria of BEG 34 allowed amplification of spore DNA from endosymbionts of Gigaspora margarita, Gigaspora decipiens, S. persica and S. castanea, but not from the Gigaspora gigantea endosymbiont (which was morphologically different) or from the cytoplasm of Gigaspora rosea (which did not contain endosymbiotic bacteria). These specific primers were successfully used as a probe for the in-situ hybridization of endobacteria in Gigaspora margarita spores. The overall rod-shaped morphology of the Gigaspora margarita, Gigaspora decipiens, S. persica and S. castanea endosymbionts was similar, and amplification and sequence analysis of the almost-complete 16S rRNA genes of several Gigaspora margarita, S. persica and S. castanea endosymbionts revealed over 98% sequence similarity. These morphological and genomic characteristics were used to assign the endosymbionts of these three species (five isolates) of arbuscular mycorrhizal fungi as 'Candidatus Glomeribacter gigasporarum' gen. nov., sp. nov.

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

    PubMed

    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.

  5. Phylogenetic trait conservatism and the evolution of functional trade-offs in arbuscular mycorrhizal fungi

    PubMed Central

    Powell, Jeff R.; Parrent, Jeri L.; Hart, Miranda M.; Klironomos, John N.; Rillig, Matthias C.; Maherali, Hafiz

    2009-01-01

    The diversity of functional and life-history traits of organisms depends on adaptation as well as the legacy of shared ancestry. Although the evolution of traits in macro-organisms is well studied, relatively little is known about character evolution in micro-organisms. Here, we surveyed an ancient and ecologically important group of microbial plant symbionts, the arbuscular mycorrhizal (AM) fungi, and tested hypotheses about the evolution of functional and life-history traits. Variation in the extent of root and soil colonization by AM fungi is constrained to a few nodes basal to the most diverse groups within the phylum, with relatively little variation associated with recent divergences. We found no evidence for a trade-off in biomass allocated to root versus soil colonization in three published glasshouse experiments; rather these traits were positively correlated. Partial support was observed for correlated evolution between fungal colonization strategies and functional benefits of the symbiosis to host plants. The evolution of increased soil colonization was positively correlated with total plant biomass and shoot phosphorus content. Although the effect of AM fungi on infection by root pathogens was phylogenetically conserved, there was no evidence for correlated evolution between the extent of AM fungal root colonization and pathogen infection. Variability in colonization strategies evolved early in the diversification of AM fungi, and we propose that these strategies were influenced by functional interactions with host plants, resulting in an evolutionary stasis resembling trait conservatism. PMID:19740877

  6. Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory.

    PubMed

    Hernandez, Rebecca R; Allen, Michael F

    2013-10-01

    Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in soils. However, their basic biology, including their activity throughout a 24-h day : night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the circadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying soil carbon sequestration, nutrient cycling and host plant success.

  7. [Ecological distribution of arbuscular mycorrhizal fungi in alpine grasslands of Tibet Plateau].

    PubMed

    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.

  8. Specific arbuscular mycorrhizal fungi associated with non-photosynthetic Petrosavia sakuraii (Petrosaviaceae).

    PubMed

    Yamato, Masahide; Yagame, Takahiro; Shimomura, Norihiro; Iwase, Koji; Takahashi, Hiroshi; Ogura-Tsujita, Yuki; Yukawa, Tomohisa

    2011-10-01

    Mycorrhizal fungi in roots of the achlorophyllous Petrosavia sakuraii (Petrosaviaceae) were identified by molecular methods. Habitats examined were plantations of the Japanese cypress Chamaecyparis obtusa in Honshu, an evergreen broad-leaved forest in Amami Island in Japan and a mixed deciduous and evergreen forest in China. Aseptate hyphal coils were observed in root cortical cells of P. sakuraii, suggesting Paris-type arbuscular mycorrhiza (AM). Furthermore, hyphal coils that had degenerated to amorphous clumps were found in various layers of the root cortex. Despite extensive sampling of P. sakuraii from various sites in Japan and China, most of the obtained AM fungal sequences of the nuclear small subunit ribosomal RNA gene were nearly identical and phylogenetic analysis revealed that they formed a single clade in the Glomus group A lineage. This suggests that the symbiotic relationship is highly specific. AM fungi of P. sakuraii were phylogenetically different from those previously detected in the roots of some mycoheterotrophic plants. In a habitat in C. obtusa plantation, approximately half of the AM fungi detected in roots of C. obtusa surrounding P. sakuraii belonged to the same clade as that of P. sakuraii. This indicates that particular AM fungi are selected by P. sakuraii from diverse indigenous AM fungi. The same AM fungi can colonize both plant species, and photosynthates of C. obtusa may be supplied to P. sakuraii through a shared AM fungal mycelial network. Although C. obtusa plantations are widely distributed throughout Japan, P. petrosavia is a rare plant species, probably because of its high specificity towards particular AM fungi.

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

    PubMed

    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. PMID:21887636

  10. Fungi in the future: Interannual variation and effects of atmospheric change on arbuscular mycorrhizal fungal communities

    DOE PAGES

    Cotton, T. E. Anne; Fitter, Alastair H.; Miller, R. Michael; Dumbrell, Alex J.; Helgason, Thorunn

    2015-01-05

    Understanding the natural dynamics of arbuscular mycorrhizal (AM) fungi and their response to global environmental change is essential for the prediction of future plant growth and ecosystem functions. We investigated the long-term temporal dynamics and effect of elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations on AM fungal communities. Molecular methods were used to characterize the AM fungal communities of soybean (Glycine max) grown under elevated and ambient atmospheric concentrations of both CO2 and O3 within a free air concentration enrichment experiment in three growing seasons over 5 yr. Elevated CO2 altered the community composition of AM fungi, increasingmore » the ratio of Glomeraceae to Gigasporaceae. By contrast, no effect of elevated O3 on AM fungal communities was detected. However, the greatest compositional differences detected were between years, suggesting that, at least in the short term, large-scale interannual temporal dynamics are stronger mediators than atmospheric CO2 concentrations of AM fungal communities. We conclude that, although atmospheric change may significantly alter AM fungal communities, this effect may be masked by the influences of natural changes and successional patterns through time. We suggest that changes in carbon availability are important determinants of the community dynamics of AM fungi.« less

  11. Fungi in the future: Interannual variation and effects of atmospheric change on arbuscular mycorrhizal fungal communities

    SciTech Connect

    Cotton, T. E. Anne; Fitter, Alastair H.; Miller, R. Michael; Dumbrell, Alex J.; Helgason, Thorunn

    2015-01-05

    Understanding the natural dynamics of arbuscular mycorrhizal (AM) fungi and their response to global environmental change is essential for the prediction of future plant growth and ecosystem functions. We investigated the long-term temporal dynamics and effect of elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations on AM fungal communities. Molecular methods were used to characterize the AM fungal communities of soybean (Glycine max) grown under elevated and ambient atmospheric concentrations of both CO2 and O3 within a free air concentration enrichment experiment in three growing seasons over 5 yr. Elevated CO2 altered the community composition of AM fungi, increasing the ratio of Glomeraceae to Gigasporaceae. By contrast, no effect of elevated O3 on AM fungal communities was detected. However, the greatest compositional differences detected were between years, suggesting that, at least in the short term, large-scale interannual temporal dynamics are stronger mediators than atmospheric CO2 concentrations of AM fungal communities. We conclude that, although atmospheric change may significantly alter AM fungal communities, this effect may be masked by the influences of natural changes and successional patterns through time. We suggest that changes in carbon availability are important determinants of the community dynamics of AM fungi.

  12. Diversity of arbuscular mycorrhizal fungi in irrigated and non-irrigated fields of southern Karnataka, India.

    PubMed

    Kumar, C P Sunil; Garampalli, Rajkumar H

    2013-03-01

    The two different agro-ecosystems were selected to study the spore density, species abundance, and diversity of arbuscular mycorrhizal fungi (AMF) in irrigated (Mandya district) and non-irrigated (Hassan district) agricultural fields in southern Karnataka region, India. A total of 22 AMF species were recorded during the study. Out of which 13 sp. were of Glomus, 4 sp. of Acaulospora, 1 sp. of Cetraspora, 1 sp. of Dentiscutata and 3 sp. of Gigaspora. The difference in species richness of AMF species in irrigated fields ranged from 5-12 sp. as compared to non-irrigated fields (5-11 sp.) and the difference may be attributed to the nutritional status of the soil. We also assumed that lower AMF colonization and abundance would be affected by water stress. Highest spore number and percent colonization of AM fungi were recorded in irrigated sites, showing 356-748 spore density and 70-92% colonization. Whereas, in non-irrigated sites, 174-341 spore density and 40-72% colonization was recorded. Different agro-climatic conditions like irrigation, soil pH, soil organic carbon, phosphorous correlated with the abundance and colonization of AM fungi. PMID:24620573

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

    PubMed

    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.

  14. Role of Arbuscular Mycorrhizal Fungi in Phytoremediation of Soil Rhizosphere Spiked with Poly Aromatic Hydrocarbons

    PubMed Central

    2005-01-01

    Results from an innovative approach to improve remediation in the rhizosphere by encouraging healthy plant growth and thus enhancing microbial activity are reported. The effect of arbuscular mycorrhizal fungi (Am) on remediation efficacy of wheat, mungbean and eggplant grown in soil spiked with polyaromatic hydrocarbons (PAH) was assessed in a pot experiment. The results of this study showed that Am inoculation enhanced dissipation amount of PAHs in planted soil, plant uptake PAHs, dissipation amount of PAHs in planted versus unplanted spiked soil and loss of PAHs by the plant-promoted biodegradation. A number of parameters were monitored including plant shoot and root dry weight, plant tissue water content, plant chlorophyll, root lipid content, oxido-reductase enzyme activities in plant and soil rhizosphere and total microbial count in the rhizospheric soil. The observed physiological data indicate that plant growth and tolerance increased with Am, but reduced by PAH. This was reflected by levels of mycorrhizal root colonization which were higher for mungbean, moderate for wheat and low for eggplant. Levels of Am colonization increased on mungbean > wheat > eggplant. This is consistent with the efficacy of plant in dissipation of PAHs in spiked soil. Highly significant positive correlations were shown between of arbuscular formation in root segments (A)) and plant water content, root lipids, peroxidase, catalase polyphenol oxidase and total microbial count in soil rhizosphere as well as PAH dissipation in spiked soil. As consequence of the treatment with Am, the plants provide a greater sink for the contaminants since they are better able to survive and grow. PMID:24049473

  15. Uptake Kinetics of Arsenic in Upland Rice Cultivar Zhonghan 221 Inoculated with Arbuscular Mycorrhizal Fungi.

    PubMed

    Chan, W F; Li, W C; Wong, M H

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) appear to be highly associated with arsenic (As) uptake in host plants because arsenate (As(V)) and phosphorus (P) share the same transporter, whereby AMF can enhance P uptake. A short-term experiment was conducted for low- (0 to 0.05 mM As) and high-affinity (0 to 2.5 mM As) uptake systems, to investigate the AMF role on As uptake mechanism in plants, which may explain As uptake kinetics in upland rice cultivar: Zhonghan 221. When concentration of As ranged from 0 to 0.05 mM, Funneliformis geosporum (Fg) significantly decreased arsenite (As(III)) and monomethylarsonicacid (MMA) uptake when (p < 0.05) compared to non-mycorrhizal (NM) treatment, since the major route for (As(III)) in rice roots-rice silicon transporter Lsi1 would be influenced by Fg inoculation at high As concentrations. Fg can also reduce As(V) uptake significantly (p < 0.05) under both uptake systems relative to NM treatment, whereas, Funneliformis mosseae (Fm) increased As(V) and MMA uptake in rice roots, with MMA uptake rate generally lower than As(III) and As(V). Using suitable AMF species inoculation with rice, As uptake and accumulation in rice grains can be reduced and the risk to human health, once consumed, can be minimized.

  16. Uptake Kinetics of Arsenic in Upland Rice Cultivar Zhonghan 221 Inoculated with Arbuscular Mycorrhizal Fungi.

    PubMed

    Chan, W F; Li, W C; Wong, M H

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) appear to be highly associated with arsenic (As) uptake in host plants because arsenate (As(V)) and phosphorus (P) share the same transporter, whereby AMF can enhance P uptake. A short-term experiment was conducted for low- (0 to 0.05 mM As) and high-affinity (0 to 2.5 mM As) uptake systems, to investigate the AMF role on As uptake mechanism in plants, which may explain As uptake kinetics in upland rice cultivar: Zhonghan 221. When concentration of As ranged from 0 to 0.05 mM, Funneliformis geosporum (Fg) significantly decreased arsenite (As(III)) and monomethylarsonicacid (MMA) uptake when (p < 0.05) compared to non-mycorrhizal (NM) treatment, since the major route for (As(III)) in rice roots-rice silicon transporter Lsi1 would be influenced by Fg inoculation at high As concentrations. Fg can also reduce As(V) uptake significantly (p < 0.05) under both uptake systems relative to NM treatment, whereas, Funneliformis mosseae (Fm) increased As(V) and MMA uptake in rice roots, with MMA uptake rate generally lower than As(III) and As(V). Using suitable AMF species inoculation with rice, As uptake and accumulation in rice grains can be reduced and the risk to human health, once consumed, can be minimized. PMID:25901895

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

    PubMed

    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 (p<0.05) total As concentration in Zhonghan 221 when compared to the non mycorrhizal (NM) treatment. The treatment inoculated with Gg + Gm increased total phosphorus (P) uptake and decreased total As uptake in the ingestible rice parts (husks and grains). In terms of AMF colonization rates, Gm had significantly higher (p<0.05) average values of 57.3% and 66.6% when grown in As0 and As40 soils, respectively, in comparison to that of Gg and Gv, and finally dropped to 3.63% when grown in As80 soil. There was a significant difference (p<0.05) between single AMF species (Gg or Gv) and AMF mixture treatments (Gg + Gv, Gg + Gm, Gv + Gm and Gg + Gv + Gm) in terms of total As concentrations in rice. No significant correlation between AMF colonization rates and As uptake in grains (r = 0.150, p > 0.01) and total P (r = 0.002, p > 0.01) were observed. PMID:22940287

  18. Arbuscular mycorrhizal fungi in saline soils: Vertical distribution at different soil depth

    PubMed Central

    Becerra, Alejandra; Bartoloni, Norberto; Cofré, Noelia; Soteras, Florencia; Cabello, Marta

    2014-01-01

    Arbuscular mycorrhizal fungi (AMF) colonize land plants in every ecosystem, even extreme conditions such as saline soils. In the present work we report for the first time the mycorrhizal status and the vertical fungal distribution of AMF spores present in the rhizospheric soil samples of four species of Chenopodiaceae (Allenrolfea patagonica, Atriplex argentina, Heterostachys ritteriana and Suaeda divaricata) at five different depths in two saline of central Argentina. Roots showed medium, low or no colonization (0–50%). Nineteen morphologically distinctive AMF species were recovered. The number of AMF spores ranged between 3 and 1162 per 100 g dry soil, and AMF spore number decreased as depth increased at both sites. The highest spore number was recorded in the upper soil depth (0–10 cm) and in S. divaricata. Depending of the host plant, some AMF species sporulated mainly in the deep soil layers (Glomus magnicaule in Allenrolfea patagonica, Septoglomus aff. constrictum in Atriplex argentina), others mainly in the top layers (G. brohultti in Atriplex argentina and Septoglomus aff. constrictum in Allenrolfea patagonica). Although the low percentages of colonization or lack of it, our results show a moderate diversity of AMF associated to the species of Chenopodiaceae investigated in this study. The taxonomical diversity reveals that AMF are adapted to extreme environmental conditions from saline soils of central Argentina. PMID:25242945

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

    PubMed

    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.

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

    PubMed

    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 (p<0.05) total As concentration in Zhonghan 221 when compared to the non mycorrhizal (NM) treatment. The treatment inoculated with Gg + Gm increased total phosphorus (P) uptake and decreased total As uptake in the ingestible rice parts (husks and grains). In terms of AMF colonization rates, Gm had significantly higher (p<0.05) average values of 57.3% and 66.6% when grown in As0 and As40 soils, respectively, in comparison to that of Gg and Gv, and finally dropped to 3.63% when grown in As80 soil. There was a significant difference (p<0.05) between single AMF species (Gg or Gv) and AMF mixture treatments (Gg + Gv, Gg + Gm, Gv + Gm and Gg + Gv + Gm) in terms of total As concentrations in rice. No significant correlation between AMF colonization rates and As uptake in grains (r = 0.150, p > 0.01) and total P (r = 0.002, p > 0.01) were observed.

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

    PubMed

    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. PMID:22673057

  2. [Effects of different peony cultivars on community structure of arbuscular mycorrhizal fungi in rhizosphere soil].

    PubMed

    Guo, Shao-Xia; Liu, Run-Jin

    2010-08-01

    This paper studied the community structure of arbuscular mycorrhizal (AM) fungi in the rhizosphere soil of different peony (Paeonia suffruticosa) cultivars grown in Zhaolou Peony Garden of Heze in Shandong Province. A number of parameters describing this community structure, e. g., spore density, species- and genera composition, species richness, distribution frequency, species diversity indices, and Sorenson's similarity coefficient, were examined. The species- and genera composition, species richness, and distribution frequency of AM fungi in rhizosphere soil varied with planted peony cultivars. A total of 10 AM fungal species were isolated from the rhizosphere soil of cultivars 'Fengdan' and 'Zhaofen', 9 species from the rhizosphere soil of 'Wulong pengsheng' and 'Luoyang red', and 8 species from the rhizosphere soil of 'Hu red'. The spore density was the highest (59 per 50 g soil) in the rhizosphere soil of 'Fengdan', but the lowest (47 per 50 g soil) in the rhizosphere soil of 'Hu red'; the species diversity index was the highest (1.89) in the rhizosphere soil of 'Zhaofen', but the lowest (1.71) in the rhizosphere soil of 'Hu red'; and the mycorrhizal colonization rate was the highest (63.6%) in rhizosphere soil of 'Fengdan' and 'Hu red', but the lowest (52.7%) in the rhizosphere soil of 'Wulong pengsheng'. The Sorenson's similarity coefficient of AM fungal species composition in the rhizosphere soil among the test cultivars ranged from 0.71 to 0.95, being the highest between 'Wulong pengsheng' and 'Fengdan', and the lowest between 'Luoyang red' and 'Hu red'. It was concluded that the gene type of peony could change the community structure of AM fungi in rhizosphere soil.

  3. Transcriptomes of Arbuscular Mycorrhizal Fungi and Litchi Host Interaction after Tree Girdling

    PubMed Central

    Shu, Bo; Li, Weicai; Liu, Liqin; Wei, Yongzan; Shi, Shengyou

    2016-01-01

    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 chinensis 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 ligase complex

  4. Transcriptomes of Arbuscular Mycorrhizal Fungi and Litchi Host Interaction after Tree Girdling.

    PubMed

    Shu, Bo; Li, Weicai; Liu, Liqin; Wei, Yongzan; Shi, Shengyou

    2016-01-01

    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 chinensis 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 ligase complex

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

    PubMed

    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.

  6. Arbuscular mycorrhizal fungi alter plant allometry and biomass–density relationships

    PubMed Central

    Zhang, Qian; Zhang, Lu; Weiner, Jacob; Tang, Jianjun; Chen, Xin

    2011-01-01

    Background and Aims Plant biomass–density relationships during self-thinning are determined mainly by allometry. Both allometry and biomass–density relationship have been shown to vary with abiotic conditions, but the effects of biotic interactions have not been investigated. Arbuscular mycorrhizal fungi (AMF) can promote plant growth and affect plant form. Here experiments were carried out to test whether AMF affect plant allometry and the self-thinning trajectory. Methods Two experiments were conducted on Medicago sativa L., a leguminous species known to be highly dependent on mycorrhiza. Two mycorrhizal levels were obtained by applying benomyl (low AMF) or not (high AMF). Experiment 1 investigated the effects of AMF on plant growth in the absence of competition. Experiment 2 was a factorial design with two mycorrhizal levels and two plant densities (6000 and 17 500 seeds m−2). Shoot biomass, root biomass and canopy radius were measured 30, 60, 90 and 120 d after sowing. The allometric relationships among these aspects of size were estimated by standardized major axis regression on log-transformed data. Key Results Shoot biomass in the absence of competition was lower under low AMF treatment. In self-thinning populations, the slope of the log (mean shoot biomass) vs. log density relationship was significantly steeper for the high AMF treatment (slope = –1·480) than for the low AMF treatment (–1·133). The canopy radius–biomass allometric exponents were not significantly affected by AMF level, but the root–shoot allometric exponent was higher in the low AMF treatment. With a high level of AMF, the biomass–density exponent can be predicted from the above-ground allometric model of self-thinning, while this was not the case when AMF were reduced by fungicide. Conclusions AMF affected the importance of below-ground relative to above-ground interactions and changed root vs. shoot allocation. This changed allometric allocation of biomass and altered

  7. Arbuscular mycorrhizal fungi: potential biocontrol agents against the damaging root hemiparasite Pedicularis kansuensis?

    PubMed

    Sui, Xiao-Lin; Li, Ai-Rong; Chen, Yan; Zhuo, Lu; Liu, Yan-Yan

    2014-04-01

    Spatial expansion of root hemiparasitic Pedicularis kansuensis in Bayanbulak Grassland of Xinjiang Uygur Autonomous Region (China) has caused great loss of herbage yield and has threatened the local livestock industry. Current management practices using manual eradication and chemical control have been proved problematic. Arbuscular mycorrhizal (AM) fungi have been suggested to be potential biocontrol agents against a number of plant pests, but experimental evidence is lacking against weedy P. kansuensis. In this study, we tested the hypothesis that inoculation with AM fungi will cause growth depression in P. kansuensis and reduce its damage to host plants. Based on the confirmation of AM status and host community of the hemiparasite in the field, a pot cultivation experiment was conducted to test the influence of an AM fungus (Glomus mosseae) on growth of P. kansuensis and the parasitized host (Elymus nutans). AM colonization was observed in roots of P. kansuensis, but the levels were much lower than those of its adjacent host species. A negative correlation between AM levels and the numbers of haustoria was detected for the field samples of the hemiparasite. Strong suppression of haustorium formation, a significant reduction in plant dry weight (DW), as well as marked reduction in the survival rate of P. kansuensis after inoculation with AM fungi was observed. In contrast, inoculation with G. mosseae increased root DW and whole plant DW of parasitized host plants. Our findings demonstrated significantly repressive effects of AM fungi on growth performance of P. kansuensis with and without the presence of a host. The potential of AM fungi as biocontrol agents against the damaging hemiparasite was confirmed.

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

    PubMed

    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. PMID:27423979

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

    PubMed

    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. PMID:22391803

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

    PubMed

    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. PMID:26991277

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

    PubMed

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

    PubMed

    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.

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

    PubMed

    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.

  14. Distinct seasonal assemblages of arbuscular mycorrhizal fungi revealed by massively parallel pyrosequencing.

    PubMed

    Dumbrell, Alex J; Ashton, Peter D; Aziz, Naveed; Feng, Gu; Nelson, Michaela; Dytham, Calvin; Fitter, Alastair H; Helgason, Thorunn

    2011-05-01

    • Understanding the dynamics of rhizosphere microbial communities is essential for predicting future ecosystem function, yet most research focuses on either spatial or temporal processes, ignoring combined spatio-temporal effects. • Using pyrosequencing, we examined the spatio-temporal dynamics of a functionally important community of rhizosphere microbes, the arbuscular mycorrhizal (AM) fungi. We sampled AM fungi from plant roots growing in a temperate grassland in a spatially explicit manner throughout a year. • Ordination analysis of the AM fungal assemblages revealed significant temporal changes in composition and structure. Alpha and beta diversity tended to be negatively correlated with the climate variables temperature and sunshine hours. Higher alpha diversity during colder periods probably reflects more even competitive interactions among AM fungal species under limited carbon availability, a conclusion supported by analysis of beta diversity which highlights how resource limitation may change localized spatial dynamics. • Results reveal distinct AM fungal assemblages in winter and summer at this grassland site. A seasonally changing supply of host-plant carbon, reflecting changes in temperature and sunshine hours, may be the driving force in regulating the temporal dynamics of AM fungal communities. Climate change effects on seasonal temperatures may therefore substantially alter future AM fungal community dynamics and ecosystem functioning.

  15. Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi.

    PubMed

    Desirò, Alessandro; Salvioli, Alessandra; Ngonkeu, Eddy L; Mondo, Stephen J; Epis, Sara; Faccio, Antonella; Kaech, Andres; Pawlowska, Teresa E; Bonfante, Paola

    2014-02-01

    Arbuscular mycorrhizal fungi (AMF) are important members of the plant microbiome. They are obligate biotrophs that colonize the roots of most land plants and enhance host nutrient acquisition. Many AMF themselves harbor endobacteria in their hyphae and spores. Two types of endobacteria are known in Glomeromycota: rod-shaped Gram-negative Candidatus Glomeribacter gigasporarum, CaGg, limited in distribution to members of the Gigasporaceae family, and coccoid Mollicutes-related endobacteria, Mre, widely distributed across different lineages of AMF. The goal of the present study is to investigate the patterns of distribution and coexistence of the two endosymbionts, CaGg and Mre, in spore samples of several strains of Gigaspora margarita. Based on previous observations, we hypothesized that some AMF could host populations of both endobacteria. To test this hypothesis, we performed an extensive investigation of both endosymbionts in G. margarita spores sampled from Cameroonian soils as well as in the Japanese G. margarita MAFF520054 isolate using different approaches (molecular phylotyping, electron microscopy, fluorescence in situ hybridization and quantitative real-time PCR). We found that a single AMF host can harbour both types of endobacteria, with Mre population being more abundant, variable and prone to recombination than the CaGg one. Both endosymbionts seem to retain their genetic and lifestyle peculiarities regardless of whether they colonize the host alone or together. These findings show for the first time that fungi support an intracellular bacterial microbiome, in which distinct types of endobacteria coexist in a single cell.

  16. Diverse communities of arbuscular mycorrhizal fungi inhabit sites with very high altitude in Tibet Plateau.

    PubMed

    Liu, Yongjun; He, Junxia; Shi, Guoxi; An, Lizhe; Öpik, Maarja; Feng, Huyuan

    2011-11-01

    Diversity of arbuscular mycorrhizal fungi (AMF) is well studied in many ecosystems, but little is known about AMF in cold-dominated regions with very high altitude. Here, we examined AMF communities associated with two plant species in the Tibet Plateau. Roots and rhizosphere soils of Dracocephalum heterophyllum (pioneer species) and Astragalus polycladus (late-successional species) were sampled at five sites with altitude from 4500 to 4800 m a.s.l. A total of 21 AMF phylotypes were identified from roots and spores following cloning and sequencing of 18S rRNA gene, including eight new phylotypes and one new family-like clade. More AMF phylotypes colonized root samples of D. heterophyllum (5.4±0.49) than of A. polycladus (1.93±0.25). Vegetation coverage was the most important factor influencing AMF community composition in roots. Globally infrequent phylotype Glo-B2 in Glomus group B was the most dominant in roots, followed by globally frequent phylotype Glo-A2 related to Glomus fasciculatum/intraradices group. Our findings suggest that a diverse AMF flora is present in the Tibet Plateau, comprising both potentially habitat-selective and generalist fungi.

  17. Fungal lipid accumulation and development of mycelial structures by two arbuscular mycorrhizal fungi.

    PubMed

    van Aarle, Ingrid M; Olsson, Pål Axel

    2003-11-01

    We monitored the development of intraradical and extraradical mycelia of the arbuscular mycorrhizal (AM) fungi Scutellospora calospora and Glomus intraradices when colonizing Plantago lanceolata. The occurrence of arbuscules (branched hyphal structures) and vesicles (lipid storage organs) was compared with the amounts of signature fatty acids. The fatty acid 16:1omega5 was used as a signature for both AM fungal phospholipids (membrane constituents) and neutral lipids (energy storage) in roots (intraradical mycelium) and in soil (extraradical mycelium). The formation of arbuscules and the accumulation of AM fungal phospholipids in intraradical mycelium followed each other closely in both fungal species. In contrast, the neutral lipids of G. intraradices increased continuously in the intraradical mycelium, while vesicle occurrence decreased after initial rapid root colonization by the fungus. S. calospora does not form vesicles and accumulated more neutral lipids in extraradical than in intraradical mycelium, while the opposite pattern was found for G. intraradices. G. intraradices allocated more of its lipids to storage than did S. calospora. Thus, within a species, the fatty acid 16:1omega5 is a good indicator for AM fungal development. The phospholipid fatty acid 16:1omega5 is especially suitable for indicating the frequency of arbuscules in the symbiosis. We propose that the ratio of neutral lipids to phospholipids is more important than is the presence of vesicles in determining the storage status of AM fungi.

  18. Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi

    PubMed Central

    Desirò, Alessandro; Salvioli, Alessandra; Ngonkeu, Eddy L; Mondo, Stephen J; Epis, Sara; Faccio, Antonella; Kaech, Andres; Pawlowska, Teresa E; Bonfante, Paola

    2014-01-01

    Arbuscular mycorrhizal fungi (AMF) are important members of the plant microbiome. They are obligate biotrophs that colonize the roots of most land plants and enhance host nutrient acquisition. Many AMF themselves harbor endobacteria in their hyphae and spores. Two types of endobacteria are known in Glomeromycota: rod-shaped Gram-negative Candidatus Glomeribacter gigasporarum, CaGg, limited in distribution to members of the Gigasporaceae family, and coccoid Mollicutes-related endobacteria, Mre, widely distributed across different lineages of AMF. The goal of the present study is to investigate the patterns of distribution and coexistence of the two endosymbionts, CaGg and Mre, in spore samples of several strains of Gigaspora margarita. Based on previous observations, we hypothesized that some AMF could host populations of both endobacteria. To test this hypothesis, we performed an extensive investigation of both endosymbionts in G. margarita spores sampled from Cameroonian soils as well as in the Japanese G. margarita MAFF520054 isolate using different approaches (molecular phylotyping, electron microscopy, fluorescence in situ hybridization and quantitative real-time PCR). We found that a single AMF host can harbour both types of endobacteria, with Mre population being more abundant, variable and prone to recombination than the CaGg one. Both endosymbionts seem to retain their genetic and lifestyle peculiarities regardless of whether they colonize the host alone or together. These findings show for the first time that fungi support an intracellular bacterial microbiome, in which distinct types of endobacteria coexist in a single cell. PMID:24008325

  19. Impact of an invasive nitrogen-fixing tree on arbuscular mycorrhizal fungi and the development of native species.

    PubMed

    Guisande-Collazo, Alejandra; González, Luís; Souza-Alonso, Pablo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate soil biotrophs that establish intimate relationships with 80 % of terrestrial plant families. Arbuscular mycorrhizal fungi obtain carbon from host plants and contribute to the acquisition of mineral nutrients, mainly phosphorus. The presence of invasive plants has been identified as a soil disturbance factor, often conditioning the structure and function of soil microorganisms. Despite the investigation of many aspects related to the invasion ofAcacia dealbata, the effect produced on the structure of AMF communities has never been assessed. We hypothesize thatA. dealbatamodifies the structure of AMF community, influencing the establishment and growth of plants that are dependent on these mutualisms. To validate our hypothesis, we carried out denaturing gradient gel electrophoresis (DGGE) analysis and also grew plants ofPlantago lanceolatain pots using roots of native shrublands or fromA. dealbata, as inoculum of AMF. Cluster analyses from DGGE indicated an alteration in the structure of AMF communities in invaded soils. After 15 weeks, we found that plants grown in pots containing native roots presented higher stem and root growth and also produced higher biomass in comparison with plants grown withA. dealbatainoculum. Furthermore, plants that presented the highest biomass and growth exhibited the maximum mycorrhizal colonization and phosphorus content. Moreover, fluorescence measurements indicated that plants grown withA. dealbatainoculum even presented higher photosynthetic damage. Our results indicate that the presence of the invaderA. dealbatamodify the composition of the arbuscular fungal community, conditioning the establishment of native plants.

  20. Impact of an invasive nitrogen-fixing tree on arbuscular mycorrhizal fungi and the development of native species

    PubMed Central

    Guisande-Collazo, Alejandra; González, Luís; Souza-Alonso, Pablo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate soil biotrophs that establish intimate relationships with 80 % of terrestrial plant families. Arbuscular mycorrhizal fungi obtain carbon from host plants and contribute to the acquisition of mineral nutrients, mainly phosphorus. The presence of invasive plants has been identified as a soil disturbance factor, often conditioning the structure and function of soil microorganisms. Despite the investigation of many aspects related to the invasion of Acacia dealbata, the effect produced on the structure of AMF communities has never been assessed. We hypothesize that A. dealbata modifies the structure of AMF community, influencing the establishment and growth of plants that are dependent on these mutualisms. To validate our hypothesis, we carried out denaturing gradient gel electrophoresis (DGGE) analysis and also grew plants of Plantago lanceolata in pots using roots of native shrublands or from A. dealbata, as inoculum of AMF. Cluster analyses from DGGE indicated an alteration in the structure of AMF communities in invaded soils. After 15 weeks, we found that plants grown in pots containing native roots presented higher stem and root growth and also produced higher biomass in comparison with plants grown with A. dealbata inoculum. Furthermore, plants that presented the highest biomass and growth exhibited the maximum mycorrhizal colonization and phosphorus content. Moreover, fluorescence measurements indicated that plants grown with A. dealbata inoculum even presented higher photosynthetic damage. Our results indicate that the presence of the invader A. dealbata modify the composition of the arbuscular fungal community, conditioning the establishment of native plants. PMID:26984185

  1. Impact of an invasive nitrogen-fixing tree on arbuscular mycorrhizal fungi and the development of native species.

    PubMed

    Guisande-Collazo, Alejandra; González, Luís; Souza-Alonso, Pablo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate soil biotrophs that establish intimate relationships with 80 % of terrestrial plant families. Arbuscular mycorrhizal fungi obtain carbon from host plants and contribute to the acquisition of mineral nutrients, mainly phosphorus. The presence of invasive plants has been identified as a soil disturbance factor, often conditioning the structure and function of soil microorganisms. Despite the investigation of many aspects related to the invasion ofAcacia dealbata, the effect produced on the structure of AMF communities has never been assessed. We hypothesize thatA. dealbatamodifies the structure of AMF community, influencing the establishment and growth of plants that are dependent on these mutualisms. To validate our hypothesis, we carried out denaturing gradient gel electrophoresis (DGGE) analysis and also grew plants ofPlantago lanceolatain pots using roots of native shrublands or fromA. dealbata, as inoculum of AMF. Cluster analyses from DGGE indicated an alteration in the structure of AMF communities in invaded soils. After 15 weeks, we found that plants grown in pots containing native roots presented higher stem and root growth and also produced higher biomass in comparison with plants grown withA. dealbatainoculum. Furthermore, plants that presented the highest biomass and growth exhibited the maximum mycorrhizal colonization and phosphorus content. Moreover, fluorescence measurements indicated that plants grown withA. dealbatainoculum even presented higher photosynthetic damage. Our results indicate that the presence of the invaderA. dealbatamodify the composition of the arbuscular fungal community, conditioning the establishment of native plants. PMID:26984185

  2. Genetic analysis of the interaction between Allium species and arbuscular mycorrhizal fungi.

    PubMed

    Galván, Guillermo A; Kuyper, Thomas W; Burger, Karin; Keizer, L C Paul; Hoekstra, Rolf F; Kik, Chris; Scholten, Olga E

    2011-03-01

    The response of Allium cepa, A. roylei, A. fistulosum, and the hybrid A. fistulosum × A. roylei to the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied. The genetic basis for response to AMF was analyzed in a tri-hybrid A. cepa × (A. roylei × A. fistulosum) population. Plant response to mycorrhizal symbiosis was expressed as relative mycorrhizal responsiveness (R') and absolute responsiveness (R). In addition, the average performance (AP) of genotypes under mycorrhizal and non-mycorrhizal conditions was determined. Experiments were executed in 2 years, and comprised clonally propagated plants of each genotype grown in sterile soil, inoculated with G. intraradices or non-inoculated. Results were significantly correlated between both years. Biomass of non-mycorrhizal and mycorrhizal plants was significantly positively correlated. R' was negatively correlated with biomass of non-mycorrhizal plants and hence unsuitable as a breeding criterion. R and AP were positively correlated with biomass of mycorrhizal and non-mycorrhizal plants. QTLs contributing to mycorrhizal response were located on a linkage map of the A. roylei × A. fistulosum parental genotype. Two QTLs from A. roylei were detected on chromosomes 2 and 3 for R, AP, and biomass of mycorrhizal plants. A QTL from A. fistulosum was detected on linkage group 9 for AP (but not R), biomass of mycorrhizal and non-mycorrhizal plants, and the number of stem-borne roots. Co-segregating QTLs for plant biomass, R and AP indicate that selection for plant biomass also selects for enhanced R and AP. Moreover, our findings suggest that modern onion breeding did not select against the response to AMF, as was suggested before for other cultivated species. Positive correlation between high number of roots, biomass and large response to AMF in close relatives of onion opens prospects to combine these traits for the development of more robust onion cultivars. PMID:21222096

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

    PubMed

    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. PMID:23292227

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

    PubMed

    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.

  5. Can arbuscular mycorrhizal fungi improve grain yield, As uptake and tolerance of rice grown under aerobic conditions?

    PubMed

    Li, H; Ye, Z H; Chan, W F; Chen, X W; Wu, F Y; Wu, S C; Wong, M H

    2011-10-01

    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(-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. PMID:21737190

  6. Native arbuscular mycorrhizal fungi (AMF) from mountain grassland (Cordoba, Argentina) I. Seasonal variation of fungal spore diversity.

    PubMed

    Lugo, Mónica A; Cabello, Marta N

    2002-01-01

    Arbuscular mycorrhizal fungi (AMF) were studied in the rhizosphere of 3 Poaceae with metabolic pathway C(3) (Briza subaristata Lam., Deyeuxia hieronymi (Hack.) Türpe and Poa stuckertii (Hack.) Parodi), 2 Poaceae with C(4) metabolic type (Eragrostis lugens Nees and Sorghastrum pellitum (Hack.) Parodi.), and a Rosaceae (Alchemilla pinnata Ruíz & Pav.) from a natural mountain grassland in Central Argentina (South America). Host species, their metabolic type, seasonal changes, and grazing effects over AM fungal diversity were analyzed. Seventeen mycorrhizal fungi taxa were found, widespread in all families of Glomales. Density of endomycorrhizal fungi was found to be strongly influenced with seasons and host metabolic pathway, although biodiversity (H), richness (S) and evenness (E) did not change. In most cases grazing did not affect these variables.

  7. Exploring the role of arbuscular mycorrhizal fungi in carbon sequestration in agricultural soil, Part III

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sequestering carbon in agricultural soils can help mitigate increases in atmospheric CO2. Work at Rodale Institute’s Farming Systems Trial indicates significant potential for carbon sequestration in organically farmed soils. A potential mechanism for this is C storage in the arbuscular mycorrhizal...

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

    NASA Astrophysics Data System (ADS)

    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

  9. The Potential Role of Arbuscular Mycorrhizal Fungi in the Restoration of Degraded Lands

    PubMed Central

    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

  10. The Potential Role of Arbuscular Mycorrhizal Fungi in the Restoration of Degraded Lands.

    PubMed

    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.

  11. The Potential Role of Arbuscular Mycorrhizal Fungi in the Restoration of Degraded Lands.

    PubMed

    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

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

    PubMed Central

    Barber, Nicholas A.; Kiers, E. Toby; Hazzard, Ruth V.; Adler, Lynn S.

    2013-01-01

    Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF) are generally considered plant mutualists because of their generally positive effects on plant nutrient status and 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. PMID:24046771

  13. Community Dynamics of Arbuscular Mycorrhizal Fungi in High-Input and Intensively Irrigated Rice Cultivation Systems

    PubMed Central

    Wang, Yutao; Li, Ting; Li, Yingwei; Björn, Lars Olof; Rosendahl, Søren; Olsson, Pål Axel; Fu, Xuelin

    2015-01-01

    Application of a mycorrhizal inoculum could be one way to increase the yield of rice plants and reduce the application of fertilizer. We therefore studied arbuscular mycorrhizal fungi (AMF) in the roots of wetland rice (Oryza sativa L.) collected at the seedling, tillering, heading, and ripening stages in four paddy wetlands that had been under a high-input and intensively irrigated rice cultivation system for more than 20 years. It was found that AMF colonization was mainly established in the heading and ripening stages. The AMF community structure was characterized in rhizosphere soils and roots from two of the studied paddy wetlands. A fragment covering the partial small subunit (SSU), the whole internal transcribed spacer (ITS), and the partial large subunit (LSU) rRNA operon regions of AMF was amplified, cloned, and sequenced from roots and soils. A total of 639 AMF sequences were obtained, and these were finally assigned to 16 phylotypes based on a phylogenetic analysis, including 12 phylotypes from Glomeraceae, one phylotype from Claroideoglomeraceae, two phylotypes from Paraglomeraceae, and one unidentified phylotype. The AMF phylotype compositions in the soils were similar between the two surveyed sites, but there was a clear discrepancy between the communities obtained from root and soil. The relatively high number of AMF phylotypes at the surveyed sites suggests that the conditions are suitable for some species of AMF and that they may have an important function in conventional rice cultivation systems. The species richness of root-colonizing AMF increased with the growth of rice, and future studies should consider the developmental stages of this crop in the exploration of AMF function in paddy wetlands. PMID:25681190

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Community dynamics of arbuscular mycorrhizal fungi in high-input and intensively irrigated rice cultivation systems.

    PubMed

    Wang, Yutao; Li, Ting; Li, Yingwei; Björn, Lars Olof; Rosendahl, Søren; Olsson, Pål Axel; Li, Shaoshan; Fu, Xuelin

    2015-04-01

    Application of a mycorrhizal inoculum could be one way to increase the yield of rice plants and reduce the application of fertilizer. We therefore studied arbuscular mycorrhizal fungi (AMF) in the roots of wetland rice (Oryza sativa L.) collected at the seedling, tillering, heading, and ripening stages in four paddy wetlands that had been under a high-input and intensively irrigated rice cultivation system for more than 20 years. It was found that AMF colonization was mainly established in the heading and ripening stages. The AMF community structure was characterized in rhizosphere soils and roots from two of the studied paddy wetlands. A fragment covering the partial small subunit (SSU), the whole internal transcribed spacer (ITS), and the partial large subunit (LSU) rRNA operon regions of AMF was amplified, cloned, and sequenced from roots and soils. A total of 639 AMF sequences were obtained, and these were finally assigned to 16 phylotypes based on a phylogenetic analysis, including 12 phylotypes from Glomeraceae, one phylotype from Claroideoglomeraceae, two phylotypes from Paraglomeraceae, and one unidentified phylotype. The AMF phylotype compositions in the soils were similar between the two surveyed sites, but there was a clear discrepancy between the communities obtained from root and soil. The relatively high number of AMF phylotypes at the surveyed sites suggests that the conditions are suitable for some species of AMF and that they may have an important function in conventional rice cultivation systems. The species richness of root-colonizing AMF increased with the growth of rice, and future studies should consider the developmental stages of this crop in the exploration of AMF function in paddy wetlands.

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

    PubMed

    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. PMID:15221579

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

    PubMed

    Barber, Nicholas A; Kiers, E Toby; Hazzard, Ruth V; Adler, Lynn S

    2013-01-01

    Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF) are generally considered plant mutualists because of their generally positive effects on plant nutrient status and 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. PMID:24046771

  18. Arbuscular mycorrhizal fungi protect a native plant from allelopathic effects of an invader.

    PubMed

    Barto, Kathryn; Friese, Carl; Cipollini, Don

    2010-04-01

    The allelopathic potential of the Eurasian invasive plant Alliaria petiolata has been well documented, with the bulk of the effects believed to be mediated by arbuscular mycorrhizal fungi (AMF). We exposed the herbaceous annual Impatiens pallida, which is native to North America, to fractionated A. petiolata extracts at four developmental stages (germination, presymbiosis growth, symbiosis formation, and symbiosis growth) by using exposure levels expected to be similar to field levels. Surprisingly, we found strong direct effects on I. pallida germination and growth, but no indirect effects on I. pallida growth mediated by AMF. We also observed strong synergistic effects with a complete A. petiolata extract that inhibited I. pallida germination and presymbiosis root growth more than either a glucosinolate or flavonoid enriched fraction alone. In fact, the flavonoid enriched fraction tended to stimulate germination and presymbiosis root growth. In contrast to these strong direct effects, I. pallida plant growth during both the symbiosis formation and symbiosis growth phases was unaffected by A. petiolata extracts. We also found no inhibition of AMF colonization of roots or soils by A. petiolata extracts. We show that AMF can actually ameliorate allelopathic effects of an invasive plant, and suggest that previously observed allelopathic effects of A. petiolata may be due to direct inhibition of plant and fungal growth before symbiosis formation. PMID:20229215

  19. Precipitation shapes communities of arbuscular mycorrhizal fungi in Tibetan alpine steppe.

    PubMed

    Zhang, Jing; Wang, Fang; Che, Rongxiao; Wang, Ping; Liu, Hanke; Ji, Baoming; Cui, Xiaoyong

    2016-01-01

    Tibetan Plateau is one of the largest and most unique habitats for organisms including arbuscular mycorrhizal fungi (AMF). However, it remains unclear how AMF communities respond to key environmental changes in this harsh environment. To test if precipitation could be a driving force in shaping AMF community structures at regional scale, we examined AMF communities associated with dominant plant species along a precipitation gradient in Tibetan alpine steppe. Rhizosphere soils were collected from five sites with annual precipitation decreasing from 400 to 50 mm. A total of 31 AMF operational taxonomic units (OTUs) were identified. AMF community composition varied significantly among sites, whereas AMF community composition did not vary among plant species. Path analysis revealed that precipitation directly affected AMF hyphal length density, and indirectly influenced AMF species richness likely through the mediation of plant coverage. Our results suggested that water availability could drive the changes of AMF communities at regional scale. Given the important roles AMF could play in the dynamics of plant communities, exploring the changes of AMF communities along key environmental gradients would help us better predict the ecosystem level responses of the Tibetan vegetation to future climate change. PMID:27002188

  20. Arbuscular mycorrhizal fungi regulate soil respiration and its response to precipitation change in a semiarid steppe.

    PubMed

    Zhang, Bingwei; Li, Shan; Chen, Shiping; Ren, Tingting; Yang, Zhiqiang; Zhao, Hanlin; Liang, Yu; Han, Xingguo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are critical links in plant-soil continuum and play a critical role in soil carbon cycles. Soil respiration, one of the largest carbon fluxes in global carbon cycle, is sensitive to precipitation change in semiarid ecosystems. In this study, a field experiment with fungicide application and water addition was conducted during 2010-2013 in a semiarid steppe in Inner Mongolia, China, and soil respiration was continuously measured to investigate the influences of AMF on soil respiration under different precipitation regimes. Results showed that soil respiration was promoted by water addition treatment especially during drought seasons, which induced a nonlinear response of soil respiration to precipitation change. Fungicide application suppressed AMF root colonization without impacts on soil microbes. AMF suppression treatment accelerated soil respiration with 2.7, 28.5 and 37.6 g C m(-2) across three seasons, which were mainly caused by the enhanced heterotrophic component. A steeper response of soil respiration rate to precipitation was found under fungicide application treatments, suggesting a greater dampening effect of AMF on soil carbon release as water availability increased. Our study highlighted the importance of AMF on soil carbon stabilization and sequestration in semiarid steppe ecosystems especially during wet seasons. PMID:26818214

  1. Bioremediation of adverse impact of cadmium toxicity on Cassia italica Mill by arbuscular mycorrhizal fungi.

    PubMed

    Hashem, Abeer; Abd Allah, E F; Alqarawi, A A; Egamberdieva, Dilfuza

    2016-01-01

    Cassia italica Mill is an important medicinal plant within the family Fabaceae. Pot experiment was conducted to evaluate cadmium stress induced changes in physiological and biochemical attributes in C. italica with and without arbuscular mycorrhizal fungi (AMF). Cadmium stressed plant showed reduced chlorophyll pigment and protein content while AMF inoculation enhanced the chlorophyll and protein content considerably. AMF also ameliorated the cadmium stress induced reduction in total chlorophyll and protein contents by 19.30% and 38.29%, respectively. Cadmium stress enhanced lipid peroxidation while AMF inoculation reduced lipid peroxidation considerably. Increase in proline and phenol content was observed due to cadmium stress and AMF inoculation caused a further increase in proline and phenol content ensuring better growth under stressed conditions. AMF alone also enhanced proline and phenol content. Activity of antioxidant enzymes enhanced under cadmium treatment and AMF inoculation further enhanced their activity thereby strengthening the antioxidant system. Enhanced activities of antioxidants and increased accumulation of osmolytes help plants to avoid damaging impact of oxidative damage. The research has shown that AMF inoculation mitigated the negative impact of stress by reducing the lipid peroxidation and enhancing the antioxidant activity. The present study strongly supports employing AMF as the biological mean for enhancing the cadmium stress tolerance of C. italica. PMID:26858537

  2. Bacteria Associated with Spores of the Arbuscular Mycorrhizal Fungi Glomus geosporum and Glomus constrictum

    PubMed Central

    Roesti, David; Ineichen, Kurt; Braissant, Olivier; Redecker, Dirk; Wiemken, Andres; Aragno, Michel

    2005-01-01

    Spores of the arbuscular mycorrhizal fungi (AMF) Glomus geosporum and Glomus constrictum were harvested from single-spore-derived pot cultures with either Plantago lanceolata or Hieracium pilosella as host plants. PCR-denaturing gradient gel electrophoresis analysis revealed that the bacterial communities associated with the spores depended more on AMF than host plant identity. The composition of the bacterial populations linked to the spores could be predominantly influenced by a specific spore wall composition or AMF exudate rather than by specific root exudates. The majority of the bacterial sequences that were common to both G. geosporum and G. constrictum spores were affiliated with taxonomic groups known to degrade biopolymers (Cellvibrio, Chondromyces, Flexibacter, Lysobacter, and Pseudomonas). Scanning electron microscopy of G. geosporum spores revealed that these bacteria are possibly feeding on the outer hyaline spore layer. The process of maturation and eventual germination of AMF spores might then benefit from the activity of the surface microorganisms degrading the outer hyaline wall layer. PMID:16269696

  3. Bioremediation of adverse impact of cadmium toxicity on Cassia italica Mill by arbuscular mycorrhizal fungi

    PubMed Central

    Hashem, Abeer; Abd_Allah, E.F.; Alqarawi, A.A.; Egamberdieva, Dilfuza

    2015-01-01

    Cassia italica Mill is an important medicinal plant within the family Fabaceae. Pot experiment was conducted to evaluate cadmium stress induced changes in physiological and biochemical attributes in C. italica with and without arbuscular mycorrhizal fungi (AMF). Cadmium stressed plant showed reduced chlorophyll pigment and protein content while AMF inoculation enhanced the chlorophyll and protein content considerably. AMF also ameliorated the cadmium stress induced reduction in total chlorophyll and protein contents by 19.30% and 38.29%, respectively. Cadmium stress enhanced lipid peroxidation while AMF inoculation reduced lipid peroxidation considerably. Increase in proline and phenol content was observed due to cadmium stress and AMF inoculation caused a further increase in proline and phenol content ensuring better growth under stressed conditions. AMF alone also enhanced proline and phenol content. Activity of antioxidant enzymes enhanced under cadmium treatment and AMF inoculation further enhanced their activity thereby strengthening the antioxidant system. Enhanced activities of antioxidants and increased accumulation of osmolytes help plants to avoid damaging impact of oxidative damage. The research has shown that AMF inoculation mitigated the negative impact of stress by reducing the lipid peroxidation and enhancing the antioxidant activity. The present study strongly supports employing AMF as the biological mean for enhancing the cadmium stress tolerance of C. italica. PMID:26858537

  4. Plant facilitation occurs between species differing in their associated arbuscular mycorrhizal fungi.

    PubMed

    Montesinos-Navarro, A; Segarra-Moragues, J G; Valiente-Banuet, A; Verdú, M

    2012-11-01

    Complementary beneficial effects of different arbuscular mycorrhizal fungi (AMF) can result in a more efficient exploitation of the soil nutrients available, thus influencing plant communities. Here, we hypothesize that plant-AMF specificity is mediated by phylogenetic constraints defining possible interactions, and that plant-AMF interaction patterns can influence plant-plant facilitation specificity. We reanalyzed previous data describing plant-plant and plant-AMF interaction at the community level to specifically test for a phylogenetic signal on plant and AMF interactions and for a relationship between plant-plant facilitation specificity and plant species differences in their AMF associates. Closely related AMF operational taxonomical units (OTUs) tend to interact with the same plant species, but there is not a significant signal in the interaction through the plant phylogeny. This indicates that the similarity in the AMF associates of two plant species is independent of their phylogenetic relatedness. Interestingly, plant-AMF interactions match plant facilitation specificity, with pairs of plant species recruiting more frequently under each other tending to have different AMF associates. An increment of AMF diversity in the rhizosphere, as a result of plant-AMF and plant-plant selectivity, is suggested as a potential driver of plant-plant facilitation. This study highlights the role of plant-AMF interactions in shaping plant community assemblages.

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

    PubMed

    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. PMID:27524990

  6. Arbuscular mycorrhizal fungi regulate soil respiration and its response to precipitation change in a semiarid steppe

    PubMed Central

    Zhang, Bingwei; Li, Shan; Chen, Shiping; Ren, Tingting; Yang, Zhiqiang; Zhao, Hanlin; Liang, Yu; Han, Xingguo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are critical links in plant–soil continuum and play a critical role in soil carbon cycles. Soil respiration, one of the largest carbon fluxes in global carbon cycle, is sensitive to precipitation change in semiarid ecosystems. In this study, a field experiment with fungicide application and water addition was conducted during 2010–2013 in a semiarid steppe in Inner Mongolia, China, and soil respiration was continuously measured to investigate the influences of AMF on soil respiration under different precipitation regimes. Results showed that soil respiration was promoted by water addition treatment especially during drought seasons, which induced a nonlinear response of soil respiration to precipitation change. Fungicide application suppressed AMF root colonization without impacts on soil microbes. AMF suppression treatment accelerated soil respiration with 2.7, 28.5 and 37.6 g C m−2 across three seasons, which were mainly caused by the enhanced heterotrophic component. A steeper response of soil respiration rate to precipitation was found under fungicide application treatments, suggesting a greater dampening effect of AMF on soil carbon release as water availability increased. Our study highlighted the importance of AMF on soil carbon stabilization and sequestration in semiarid steppe ecosystems especially during wet seasons. PMID:26818214

  7. [Effects of arbuscular mycorrhizal fungi on the toxicity of chlorothalonil on upland rice (Oryzal sativa L.)].

    PubMed

    Zhang, Xu-hong; Lin, Ai-jun; Cui, Yu-jing

    2007-05-01

    Upland rice was selected as a host plant in a greenhouse-pot-culture experiment to investigate the effects of chlorothalonil and arbuscular mycorrhizal fungi (AMF) on the growth and oxidative damage under chlorothalonil stress. The plants were grown with three concentrations of chlorothalonil (0, 50 and 100 mg x kg(-1) soil). The results suggested that chlorothalonil inhibited the growth of upland rice and reduced dry weight of upland rice shoot from 2.5 g x pot(-1) to 1.0 g x pot(-1), and the root dry weight was reduced from 0.9 g x pot(-1) to 0.3 g x pot(-1). However, with AMF colonization the dry weight of upland rice was increased to 2.1 g x pot(-1). With 50 mg x kg(-1) chlorothalonil addition, the P uptake was reduced from 3200 microg x pot(-1) to 860 microg x pot(-1), but the AMF colonization could increased the P uptake to 1900 microg x pot(-1). Chlorothalonil induced oxidative stress indicating by the changes in activities of antioxidative enzyme and AMF colonization could alleviate the oxidative stress. These results showed that chlorothalonil induced oxidative stress and inhibited P uptake in upland rice and AMF could decrease the side effects of chlorothalonil by increasing P uptake and decreasing oxidative damages.

  8. Arbuscular mycorrhizal fungi reduced the ratios of inorganic/organic arsenic in rice grains.

    PubMed

    Li, H; Chen, X W; Wong, M H

    2016-02-01

    Arbuscular mycorrhizal fungi (AMF) - Rhizophagus intraradices was inoculated to rice to investigate its effects on arsenic (As) uptake, grain As speciation, and rhizospheric As concentration of six rice cultivars grown in As-amended soil (60 mg As kg(-1) soil). The AMF inoculation induced either positive, neutral or negative responses in rice grown in As contaminated soil, suggesting that functional diversity may exist in AMF symbiosis when As is taken up and transferred. The ratios of inorganic/organic As concentrations in rice grains of all cultivars were significantly reduced by AMF, that involved the transformation of inorganic As into less toxic organic form dimethylarsinic acid (DMA) in rice. AMF decreased significantly total As and inorganic As concentrations in rice grains of Handao 3. Positive correlations (R(2) = 0.30-0.56, P < 0.05) between As in the rhizospheric soil solution and As in rice grain at different periods were observed. This inferred that the As survey of soil solution can be an effective measure for evaluating As in grains.

  9. Effect of arbuscular mycorrhizal fungi on phytoextraction by corn (Zea mays) of lead-contaminated soil.

    PubMed

    Hovsepyan, A; Greipsson, S

    2004-01-01

    The role of arbuscular mycorrhizal fungi (AMF) in lead (Pb) uptake by corn (Zea mays) grown in soil supplemented with Pb was examined. Plants were subjected to four Pb levels: 0 (control); 10 (low); 100 (medium); and 500 mg L(-1) (high). At each Pb level, plants were grown in soil without and with fungicide (benomyl) (20 mg kg(-1)) to suppress AMF activity. Benomyl significantly reduced AMF colonization at high. medium, and zero Pb exposures. Benomyl application resulted in significantly lower concentrations of phosphorus in leaves at low and medium Pb exposures. The benomyl-treated plants had higher Pb and manganese concentrations in leaves than plants not treated with benomyl. In addition, benomyl-treated plants had generally lower concentrations of zinc and copper in leaves than plants not treated with benomyl. These results suggest that the role of AMF in heavy metal uptake is metal specific. Based on this work, the use of benomyl on soils contaminated with Pb can be recommended in phytoextraction.

  10. Phylogenetic reference data for systematics and phylotaxonomy of arbuscular mycorrhizal fungi from phylum to species level.

    PubMed

    Krüger, Manuela; Krüger, Claudia; Walker, Christopher; Stockinger, Herbert; Schüssler, Arthur

    2012-03-01

    Although the molecular phylogeny, evolution and biodiversity of arbuscular mycorrhizal fungi (AMF) are becoming clearer, phylotaxonomically reliable sequence data are still limited. To fill this gap, a data set allowing resolution and environmental tracing across all taxonomic levels is provided. Two overlapping nuclear DNA regions, totalling c. 3 kb, were analysed: the small subunit (SSU) rRNA gene (up to 1800 bp) and a fragment spanning c. 250 bp of the SSU rDNA, the internal transcribed spacer (ITS) region (c. 475-520 bp) and c. 800 bp of the large subunit (LSU) rRNA gene. Both DNA regions together could be analysed for 35 described species, the SSU rDNA for c. 76 named and 18 as yet undefined species, and the ITS region or LSU rDNA, or a combination of both, for c. 91 named and 16 as yet undefined species. Present phylogenetic analyses, based on the three rDNA markers, provide reliable and robust resolution from phylum to species level. Altogether, 109 named species and 27 cultures representing as yet undefined species were analysed. This study provides a reference data set for molecular systematics and environmental community analyses of AMF, including analyses based on deep sequencing.

  11. Arbuscular mycorrhizal fungi regulate soil respiration and its response to precipitation change in a semiarid steppe

    NASA Astrophysics Data System (ADS)

    Zhang, Bingwei; Li, Shan; Chen, Shiping; Ren, Tingting; Yang, Zhiqiang; Zhao, Hanlin; Liang, Yu; Han, Xingguo

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are critical links in plant–soil continuum and play a critical role in soil carbon cycles. Soil respiration, one of the largest carbon fluxes in global carbon cycle, is sensitive to precipitation change in semiarid ecosystems. In this study, a field experiment with fungicide application and water addition was conducted during 2010–2013 in a semiarid steppe in Inner Mongolia, China, and soil respiration was continuously measured to investigate the influences of AMF on soil respiration under different precipitation regimes. Results showed that soil respiration was promoted by water addition treatment especially during drought seasons, which induced a nonlinear response of soil respiration to precipitation change. Fungicide application suppressed AMF root colonization without impacts on soil microbes. AMF suppression treatment accelerated soil respiration with 2.7, 28.5 and 37.6 g C m‑2 across three seasons, which were mainly caused by the enhanced heterotrophic component. A steeper response of soil respiration rate to precipitation was found under fungicide application treatments, suggesting a greater dampening effect of AMF on soil carbon release as water availability increased. Our study highlighted the importance of AMF on soil carbon stabilization and sequestration in semiarid steppe ecosystems especially during wet seasons.

  12. Cohorts of arbuscular mycorrhizal fungi (AMF) in Vitis vinifera, a typical Mediterranean fruit crop.

    PubMed

    Balestrini, Raffaella; Magurno, Franco; Walker, Christopher; Lumini, Erica; Bianciotto, Valeria

    2010-08-01

    In field conditions, grapevine roots normally are colonized by arbuscular mycorrhizal fungi (AMF). However, little is published, from either morphological or molecular studies, on the species composition of these symbionts in production vineyards. The AMF biodiversity of two Piedmont vineyards (at Neive and Lessona), characterized by different soil features, was investigated by morphological and molecular analyses. Several morphotypes were identified from the two vineyard soils. Community composition of AMF, both in soil and root samples, was then analysed with molecular approach to amplify a portion (550 bp) of AM fungal SSU rDNA. Phylogenetic analyses show a different distribution of sequences from the two sites in the main glomeromycotan groups. In the Neive site, the Glomeraceae group A is the only one well represented whereas more groups were found at Lessona. Among the more representative operational taxonomic units (OTUs), only one related to the Glomus irregulare phylotype was shared between the two vineyard soils. The data obtained in this work together with similar results in literature on this important fruit crop reinforce the concept that the general AMF assemblage structure and composition in vineyards might be influenced more by soil type than by host plant features (age, vegetative stages) or management practices.

  13. Diversity of Arbuscular Mycorrhizal Fungi in a Brazilian Atlantic Forest Toposequence.

    PubMed

    Bonfim, Joice Andrade; Vasconcellos, Rafael Leandro Figueiredo; Gumiere, Thiago; de Lourdes Colombo Mescolotti, Denise; Oehl, Fritz; Nogueira Cardoso, Elke Jurandy Bran

    2016-01-01

    The diversity of arbuscular mycorrhizal fungi (AMF) was studied in the Atlantic Forest in Serra do Mar Park (SE Brazil), based on seven host plants in relationship to their soil environment, altitude and seasonality. The studied plots along an elevation gradient are located at 80, 600, and 1,000 m. Soil samples (0-20 cm) were collected in four seasons from SE Brazilian winter 2012 to autumn 2013. AMF spores in rhizosperic soils were morphologically classified and chemical, physical and microbiological soil caracteristics were determined. AMF diversity in roots was evaluated using the NS31/AM1 primer pair, with subsequent cloning and sequencing. In the rhizosphere, 58 AMF species were identified. The genera Acaulospora and Glomus were predominant. However, in the roots, only 14 AMF sequencing groups were found and all had high similarity to Glomeraceae. AMF species identities varied between altitudes and seasons. There were species that contributed the most to this variation. Some soil characteristics (pH, organic matter, microbial activity and microbial biomass carbon) showed a strong relationship with the occurrence of certain species. The highest AMF species diversity, based on Shannon's diversity index, was found for the highest altitude. Seasonality did not affect the diversity. Our results show a high AMF diversity, higher than commonly found in the Atlantic Forest. The AMF detected in roots were not identical to those detected in rhizosperic soil and differences in AMF communities were found in different altitudes even in geographically close-lying sites.

  14. Precipitation shapes communities of arbuscular mycorrhizal fungi in Tibetan alpine steppe.

    PubMed

    Zhang, Jing; Wang, Fang; Che, Rongxiao; Wang, Ping; Liu, Hanke; Ji, Baoming; Cui, Xiaoyong

    2016-03-22

    Tibetan Plateau is one of the largest and most unique habitats for organisms including arbuscular mycorrhizal fungi (AMF). However, it remains unclear how AMF communities respond to key environmental changes in this harsh environment. To test if precipitation could be a driving force in shaping AMF community structures at regional scale, we examined AMF communities associated with dominant plant species along a precipitation gradient in Tibetan alpine steppe. Rhizosphere soils were collected from five sites with annual precipitation decreasing from 400 to 50 mm. A total of 31 AMF operational taxonomic units (OTUs) were identified. AMF community composition varied significantly among sites, whereas AMF community composition did not vary among plant species. Path analysis revealed that precipitation directly affected AMF hyphal length density, and indirectly influenced AMF species richness likely through the mediation of plant coverage. Our results suggested that water availability could drive the changes of AMF communities at regional scale. Given the important roles AMF could play in the dynamics of plant communities, exploring the changes of AMF communities along key environmental gradients would help us better predict the ecosystem level responses of the Tibetan vegetation to future climate change.

  15. Bioremediation of adverse impact of cadmium toxicity on Cassia italica Mill by arbuscular mycorrhizal fungi.

    PubMed

    Hashem, Abeer; Abd Allah, E F; Alqarawi, A A; Egamberdieva, Dilfuza

    2016-01-01

    Cassia italica Mill is an important medicinal plant within the family Fabaceae. Pot experiment was conducted to evaluate cadmium stress induced changes in physiological and biochemical attributes in C. italica with and without arbuscular mycorrhizal fungi (AMF). Cadmium stressed plant showed reduced chlorophyll pigment and protein content while AMF inoculation enhanced the chlorophyll and protein content considerably. AMF also ameliorated the cadmium stress induced reduction in total chlorophyll and protein contents by 19.30% and 38.29%, respectively. Cadmium stress enhanced lipid peroxidation while AMF inoculation reduced lipid peroxidation considerably. Increase in proline and phenol content was observed due to cadmium stress and AMF inoculation caused a further increase in proline and phenol content ensuring better growth under stressed conditions. AMF alone also enhanced proline and phenol content. Activity of antioxidant enzymes enhanced under cadmium treatment and AMF inoculation further enhanced their activity thereby strengthening the antioxidant system. Enhanced activities of antioxidants and increased accumulation of osmolytes help plants to avoid damaging impact of oxidative damage. The research has shown that AMF inoculation mitigated the negative impact of stress by reducing the lipid peroxidation and enhancing the antioxidant activity. The present study strongly supports employing AMF as the biological mean for enhancing the cadmium stress tolerance of C. italica.

  16. The Use of Arbuscular Mycorrhizal Fungi to Improve Strawberry Production in Coir Substrate

    PubMed Central

    Robinson Boyer, Louisa; Feng, Wei; Gulbis, Natallia; Hajdu, Klara; Harrison, Richard J.; Jeffries, Peter; Xu, Xiangming

    2016-01-01

    Strawberry is an important fruit crop within the UK. To reduce the impact of soil-borne diseases and extend the production season, more than half of the UK strawberry production is now in substrate (predominantly coir) under protection. Substrates such as coir are usually depleted of microbes including arbuscular mycorrhizal fungi (AMF) and consequently the introduction of beneficial microbes is likely to benefit commercial cropping systems. Inoculating strawberry plants in substrate other than coir has been shown to increase plants tolerance to soil-borne pathogens and water stress. We carried out studies to investigate whether AMF could improve strawberry production in coir under low nitrogen input and regulated deficit irrigation. Application of AMF led to an appreciable increase in the size and number of class I fruit, especially under either deficient irrigation or low nitrogen input condition. However, root length colonization by AMF was reduced in strawberry grown in coir compared to soil and Terragreen. Furthermore, the appearance of AMF colonizing strawberry and maize roots grown in coir showed some physical differences from the structure in colonized roots in soil and Terragreen: the colonization structure appeared to be more compact and smaller in coir. PMID:27594859

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

    PubMed Central

    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. PMID:27524990

  18. Relatedness among arbuscular mycorrhizal fungi drives plant growth and intraspecific fungal coexistence.

    PubMed

    Roger, Aurélien; Colard, Alexandre; Angelard, Caroline; Sanders, Ian R

    2013-11-01

    Arbuscular mycorrhizal fungi (AMF) form symbioses with most plant species. They are ecologically important determinants of plant growth and diversity. Considerable genetic variation occurs in AMF populations. Thus, plants are exposed to AMF of varying relatedness to each other. Very little is known about either the effects of coexisting AMF on plant growth or which factors influence intraspecific AMF coexistence within roots. No studies have addressed whether the genetics of coexisting AMF, and more specifically their relatedness, influences plant growth and AMF coexistence. Relatedness is expected to influence coexistence between individuals, and it has been suggested that decreasing ability of symbionts to coexist can have negative effects on the growth of the host. We tested the effect of a gradient of AMF genetic relatedness on the growth of two plant species. Increasing relatedness between AMFs lead to markedly greater plant growth (27% biomass increase with closely related compared to distantly related AMF). In one plant species, closely related AMF coexisted in fairly equal proportions but decreasing relatedness lead to a very strong disequilibrium between AMF in roots, indicating much stronger competition. Given the strength of the effects with such a shallow relatedness gradient and the fact that in the field plants are exposed to a steeper gradient, we consider that AMF relatedness can have a strong role in plant growth and the ability of AMF to coexist. We conclude that AMF relatedness is a driver of plant growth and that relatedness is also a strong driver of intraspecific coexistence of these ecologically important symbionts. PMID:23823490

  19. Arbuscular mycorrhizal fungi reduced the ratios of inorganic/organic arsenic in rice grains.

    PubMed

    Li, H; Chen, X W; Wong, M H

    2016-02-01

    Arbuscular mycorrhizal fungi (AMF) - Rhizophagus intraradices was inoculated to rice to investigate its effects on arsenic (As) uptake, grain As speciation, and rhizospheric As concentration of six rice cultivars grown in As-amended soil (60 mg As kg(-1) soil). The AMF inoculation induced either positive, neutral or negative responses in rice grown in As contaminated soil, suggesting that functional diversity may exist in AMF symbiosis when As is taken up and transferred. The ratios of inorganic/organic As concentrations in rice grains of all cultivars were significantly reduced by AMF, that involved the transformation of inorganic As into less toxic organic form dimethylarsinic acid (DMA) in rice. AMF decreased significantly total As and inorganic As concentrations in rice grains of Handao 3. Positive correlations (R(2) = 0.30-0.56, P < 0.05) between As in the rhizospheric soil solution and As in rice grain at different periods were observed. This inferred that the As survey of soil solution can be an effective measure for evaluating As in grains. PMID:26688259

  20. Evidence for the sexual origin of heterokaryosis in arbuscular mycorrhizal fungi.

    PubMed

    Ropars, Jeanne; Toro, Kinga Sędzielewska; Noel, Jessica; Pelin, Adrian; Charron, Philippe; Farinelli, Laurent; Marton, Timea; Krüger, Manuela; Fuchs, Jörg; Brachmann, Andreas; Corradi, Nicolas

    2016-01-01

    Sexual reproduction is ubiquitous among eukaryotes, and fully asexual lineages are extremely rare. Prominent among ancient asexual lineages are the arbuscular mycorrhizal fungi (AMF), a group of plant symbionts with a multinucleate cytoplasm. Genomic divergence among co-existing nuclei was proposed to drive the evolutionary success of AMF in the absence of sex(1), but this hypothesis has been contradicted by recent genome analyses that failed to find significant genetic diversity within an AMF isolate(2,3). Here, we set out to resolve issues surrounding the genome organization and sexual potential of AMF by exploring the genomes of five isolates of Rhizophagus irregularis, a model AMF. We find that genetic diversity in this species varies among isolates and is structured in a homo-dikaryon-like manner usually linked with the existence of a sexual life cycle. We also identify a putative AMF mating-type locus, containing two genes with structural and evolutionary similarities with the mating-type locus of some Dikarya. Our analyses suggest that this locus may be multi-allelic and that AMF could be heterothallic and bipolar. These findings reconcile opposing views on the genome organization of these ubiquitous plant symbionts and open avenues for strain improvement and environmental application of these organisms. PMID:27572831

  1. Arbuscular mycorrhizal fungi in a semiarid copper mining area in Brazil.

    PubMed

    da Silva, Gladstone Alves; Trufem, Sandra Farto Botelho; Saggin Júnior, Orivaldo José; Maia, Leonor Costa

    2005-01-01

    The occurrence of arbuscular mycorrhizal fungi (AMF) in a copper mining area was investigated. Soil samples were collected from six sites at the Mineração Caraiba, Bahia State, northeastern Brazil, comprising: (1) a site that receives the waste product; (2) a site that receives low grade deposits; (3) the interface between the caatinga and site 1; (4) the surroundings of the industrial area; (5) the site for extracting topsoil for land filling; (6) the preserved caatinga. Thirty-two plant species were identified around the collection locations. Trap cultures were maintained in the greenhouse for 3 months, using bahia grass ( Paspalum notatum Flügge) as the host plant. Spores were extracted from soil and 21 AMF species (15 Glomus and one of each of Acaulospora, Archaeospora, Entrophospora, Gigaspora , Paraglomus and Scutellospora) were identified. In site 1, plants or AMF were not found during the dry season. Site 6, with native vegetation, had the highest number of plants and AMF species. The disturbed sites showed less plant diversification, with the community of AMF being quantitative and qualitatively affected by disturbance. PMID:14767726

  2. [Effects of copper stress on the function of arbuscular mycorrhizal fungi community].

    PubMed

    Yang, Ru-yi; Zan, Shu-ting; Li, Jing; Su, Nan-nan; Sun, Wen-wen; Guo, Fu-yu; Zhou, Gang

    2015-05-01

    The functional differences of arbuscular mycorrhizal fungi (AMF) isolates from different sources have been extensively investigated in the last two decades. However, previous studies were mostly based on individual AMF species and the community level comparison was not addressed properly. Furthermore, many studies did not distinguish the difference between the effects of AMF source and community structure on their function, let alone concerned the significance of host plant. This study evaluated the effects of copper (Cu) stress on AMF community structure and compared the differences of AMF communities from Cu contaminated and uncontaminated substrates on performance of Zea mays through two short-term greenhouse pot culture experiments. The results showed that spore abundance and composition of AMF communities were changed dramatically under Cu stress compared with the control. The communities dominated by Rhizophagus intraradices and Claroideoglomus etunicatum from Cu contaminated soils conferred more benefits on Z. mays in terms of plant growth and physiological properties relative to that from control governed by Funneliformis mosseae.

  3. Improved PCR primers for the detection and identification of arbuscular mycorrhizal fungi.

    PubMed

    Lee, Jaikoo; Lee, Sangsun; Young, J Peter W

    2008-08-01

    A set of PCR primers that should amplify all subgroups of arbuscular mycorrhizal fungi (AMF, Glomeromycota), but exclude sequences from other organisms, was designed to facilitate rapid detection and identification directly from field-grown plant roots. The small subunit rRNA gene was targeted for the new primers (AML1 and AML2) because phylogenetic relationships among the Glomeromycota are well understood for this gene. Sequence comparisons indicate that the new primers should amplify all published AMF sequences except those from Archaeospora trappei. The specificity of the new primers was tested using 23 different AMF spore morphotypes from trap cultures and Miscanthus sinensis, Glycine max and Panax ginseng roots sampled from the field. Non-AMF DNA of 14 plants, 14 Basidiomycota and 18 Ascomycota was also tested as negative controls. Sequences amplified from roots using the new primers were compared with those obtained using the established NS31 and AM1 primer combination. The new primers have much better specificity and coverage of all known AMF groups. PMID:18631176

  4. The Use of Arbuscular Mycorrhizal Fungi to Improve Strawberry Production in Coir Substrate.

    PubMed

    Robinson Boyer, Louisa; Feng, Wei; Gulbis, Natallia; Hajdu, Klara; Harrison, Richard J; Jeffries, Peter; Xu, Xiangming

    2016-01-01

    Strawberry is an important fruit crop within the UK. To reduce the impact of soil-borne diseases and extend the production season, more than half of the UK strawberry production is now in substrate (predominantly coir) under protection. Substrates such as coir are usually depleted of microbes including arbuscular mycorrhizal fungi (AMF) and consequently the introduction of beneficial microbes is likely to benefit commercial cropping systems. Inoculating strawberry plants in substrate other than coir has been shown to increase plants tolerance to soil-borne pathogens and water stress. We carried out studies to investigate whether AMF could improve strawberry production in coir under low nitrogen input and regulated deficit irrigation. Application of AMF led to an appreciable increase in the size and number of class I fruit, especially under either deficient irrigation or low nitrogen input condition. However, root length colonization by AMF was reduced in strawberry grown in coir compared to soil and Terragreen. Furthermore, the appearance of AMF colonizing strawberry and maize roots grown in coir showed some physical differences from the structure in colonized roots in soil and Terragreen: the colonization structure appeared to be more compact and smaller in coir. PMID:27594859

  5. Reducing nitrogen runoff from paddy fields with arbuscular mycorrhizal fungi under different fertilizer regimes.

    PubMed

    Zhang, Shujuan; Wang, Li; Ma, Fang; Zhang, Xue; Fu, Dafang

    2016-08-01

    Nitrogen (N) runoff from paddy fields serves as one of the main sources of water pollution. Our aim was to reduce N runoff from paddy fields by fertilizer management and inoculation with arbuscular mycorrhizal fungi (AMF). In northeast China, Shuangcheng city in Heilongjiang province, a field experiment was conducted, using rice provided with 0%, 20%, 40%, 60%, 80%, and 100% of the local norm of fertilization (including N, phosphorus and potassium), with or without inoculation with Glomus mosseae. The volume, concentrations of total N (TN), dissolved N (DN) and particulate N (PN) of runoff water were measured. We found that the local norm of fertilization led to 18.9kg/ha of N runoff during rice growing season, with DN accounting for 60%-70%. We also found that reduction in fertilization by 20% cut down TN runoff by 8.2% while AMF inoculation decreased N runoff at each fertilizer level and this effect was inhibited by high fertilization. The combination of inoculation with AMF and 80% of the local norm of fertilization was observed to reduce N runoff by 27.2%. Conclusively, we suggested that the contribution of AMF inoculation combined with decreasing fertilization should get more attention to slow down water eutrophication by reducing N runoff from paddy fields. PMID:27521940

  6. Precipitation shapes communities of arbuscular mycorrhizal fungi in Tibetan alpine steppe

    PubMed Central

    Zhang, Jing; Wang, Fang; Che, Rongxiao; Wang, Ping; Liu, Hanke; Ji, Baoming; Cui, Xiaoyong

    2016-01-01

    Tibetan Plateau is one of the largest and most unique habitats for organisms including arbuscular mycorrhizal fungi (AMF). However, it remains unclear how AMF communities respond to key environmental changes in this harsh environment. To test if precipitation could be a driving force in shaping AMF community structures at regional scale, we examined AMF communities associated with dominant plant species along a precipitation gradient in Tibetan alpine steppe. Rhizosphere soils were collected from five sites with annual precipitation decreasing from 400 to 50 mm. A total of 31 AMF operational taxonomic units (OTUs) were identified. AMF community composition varied significantly among sites, whereas AMF community composition did not vary among plant species. Path analysis revealed that precipitation directly affected AMF hyphal length density, and indirectly influenced AMF species richness likely through the mediation of plant coverage. Our results suggested that water availability could drive the changes of AMF communities at regional scale. Given the important roles AMF could play in the dynamics of plant communities, exploring the changes of AMF communities along key environmental gradients would help us better predict the ecosystem level responses of the Tibetan vegetation to future climate change. PMID:27002188

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

    PubMed

    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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27748365

  9. The Use of Arbuscular Mycorrhizal Fungi to Improve Strawberry Production in Coir Substrate

    PubMed Central

    Robinson Boyer, Louisa; Feng, Wei; Gulbis, Natallia; Hajdu, Klara; Harrison, Richard J.; Jeffries, Peter; Xu, Xiangming

    2016-01-01

    Strawberry is an important fruit crop within the UK. To reduce the impact of soil-borne diseases and extend the production season, more than half of the UK strawberry production is now in substrate (predominantly coir) under protection. Substrates such as coir are usually depleted of microbes including arbuscular mycorrhizal fungi (AMF) and consequently the introduction of beneficial microbes is likely to benefit commercial cropping systems. Inoculating strawberry plants in substrate other than coir has been shown to increase plants tolerance to soil-borne pathogens and water stress. We carried out studies to investigate whether AMF could improve strawberry production in coir under low nitrogen input and regulated deficit irrigation. Application of AMF led to an appreciable increase in the size and number of class I fruit, especially under either deficient irrigation or low nitrogen input condition. However, root length colonization by AMF was reduced in strawberry grown in coir compared to soil and Terragreen. Furthermore, the appearance of AMF colonizing strawberry and maize roots grown in coir showed some physical differences from the structure in colonized roots in soil and Terragreen: the colonization structure appeared to be more compact and smaller in coir.

  10. Mollicutes-related endobacteria thrive inside liverwort-associated arbuscular mycorrhizal fungi.

    PubMed

    Desirò, Alessandro; Naumann, Maria; Epis, Sara; Novero, Mara; Bandi, Claudio; Genre, Andrea; Bonfante, Paola

    2013-03-01

    Arbuscular mycorrhizal fungi (AMF) can host Gram-positive endobacteria (BLOs) in their cytoplasm. These have been identified as Mollicutes-related microbes based on an inventory of AMF spores from fungal collections. Bacteria-like organisms (BLOs) of unknown identity have also been reported in the cytoplasm of AMF associated with liverworts, the earliest-diverged extant lineage of land plants. A combination of morphological, molecular and phylogenetic analyses revealed that three samples of two liverwort species (Conocephalum conicum and Lunularia cruciata) growing spontaneously in a botanical garden harboured AMF belonging to Glomerales, and these, in turn, hosted coccoid BLOs. 16S rDNA sequences from these BLOs clustered with the Mollicutes sequences identified from the spore collections but revealed the presence of novel phylotypes. Electron microscopy and fluorescence in situ hybridization (FISH) confirmed the presence of BLOs inside the cytoplasm of AMF hyphae colonizing the liverwort thalli. The high genetic variability of BLOs in liverwort-AMF associations thriving in the same ecological niche raises questions about the mechanisms underlying such diversity.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Morphological types of arbuscular mycorrhizal fungi in roots of understory plants in Japanese deciduous broadleaved forests.

    PubMed

    Yamato, Masahide; Iwasaki, Masahiro

    2002-12-01

    Morphological types of arbuscular mycorrhizal (AM) fungi in roots of understorey plants were examined in three different Japanese deciduous broadleaved forests. In total, 43 species belonging to 33 genera from 27 families were examined for the morphological types of AM. The number of flowering plant species having Paris-type AM was greater than those having Arum-type AM in each plot. This tendency was more prominent in herbaceous plants than woody plants with nine species having Paris-type associations among ten herbaceous plant species examined. Therefore, it is suggested from the ecological point of view that Paris-type associations could be advantageous for the herbaceous understorey plants growing slowly in these environments. The influence of plant identity on the morphological types of AM was also discussed by arranging the plants examined with the morphological types in a current plant phylogeny scheme. In this study, some new records on the morphological types of AM in some new plant families were obtained including the first report of a typical Arum-type AM in gymnosperms.

  13. Host Preferences of Arbuscular Mycorrhizal Fungi Colonizing Annual Herbaceous Plant Species in Semiarid Mediterranean Prairies

    PubMed Central

    Torrecillas, E.; Roldán, A.

    2012-01-01

    In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems. PMID:22752164

  14. Meta-Analysis of Interactions between Arbuscular Mycorrhizal Fungi and Biotic Stressors of Plants

    PubMed Central

    Dai, Yajun; Wang, Xiaohua; Zhu, Liqun; Bian, Xinmin

    2014-01-01

    Naturally, simultaneous interactions occurred among plants, herbivores, and soil biota, that is, arbuscular mycorrhizal fungi (AMF), nematodes, and fungal pathogens. These multiple interactions play fundamental roles in driving process, structure, and functioning of ecosystems. In this study, we conducted a meta-analysis with 144 papers to investigate the interactions between AMF and plant biotic stressors and their effects on plant growth performance. We found that AMF enhanced plant tolerance to herbivores, nematodes, and fungal pathogens. We also found reciprocal inhibition between AMF and nematodes as well as fungal pathogens, but unidirectional inhibition for AMF on herbivores. Negative effects of AMF on biotic stressors of plants depended on herbivore feeding sites and actioning modes of fungal pathogens. More performance was reduced in root-feeding than in shoot-feeding herbivores and in rotting- than in wilt-fungal pathogens. However, no difference was found for AMF negative effects between migratory and sedentary nematodes. In return, nematodes and fungal pathogens generated more reduction of root colonization in Non-Glomeraceae than in Glomeraceae. Our results suggested that AMF positive effects on plants might be indirectly mediated by competitive inhibition with biotic stressors of plants. These positive and negative interactions make potential contributions to maintaining ecosystem stability and functioning. PMID:24558327

  15. Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability

    PubMed Central

    Zhang, Haoqiang; Liu, Zhenkun; Chen, Hui; Tang, Ming

    2016-01-01

    Robinia pseudoacacia L. (black locust) is a widely planted tree species on Loess Plateau for revegetation. Due to its symbiosis forming capability with arbuscular mycorrhizal (AM) fungi, we explored the influence of arbuscular mycorrhizal fungi on plant biomass, root morphology, root tensile strength and soil aggregate stability in a pot experiment. We inoculated R. pseudoacacia with/without AM fungus (Rhizophagus irregularis or Glomus versiforme), and measured root colonization, plant growth, 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. PMID:27064570

  16. Symbiosis of Arbuscular Mycorrhizal Fungi and Robinia pseudoacacia L. Improves Root Tensile Strength and Soil Aggregate Stability.

    PubMed

    Zhang, Haoqiang; Liu, Zhenkun; Chen, Hui; Tang, Ming

    2016-01-01

    Robinia pseudoacacia L. (black locust) is a widely planted tree species on Loess Plateau for revegetation. Due to its symbiosis forming capability with arbuscular mycorrhizal (AM) fungi, we explored the influence of arbuscular mycorrhizal fungi on plant biomass, root morphology, root tensile strength and soil aggregate stability in a pot experiment. We inoculated R. pseudoacacia with/without AM fungus (Rhizophagus irregularis or Glomus versiforme), and measured root colonization, plant growth, 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.

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

    PubMed

    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

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

    PubMed

    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

  19. Casuarina in Africa: distribution, role and importance of arbuscular mycorrhizal, ectomycorrhizal fungi and Frankia on plant development.

    PubMed

    Diagne, Nathalie; Diouf, Diegane; Svistoonoff, Sergio; Kane, Aboubacry; Noba, Kandioura; Franche, Claudine; Bogusz, Didier; Duponnois, Robin

    2013-10-15

    Exotic trees were introduced in Africa to rehabilitate degraded ecosystems. Introduced species included several Australian species belonging to the Casuarinaceae family. Casuarinas trees grow very fast and are resistant to drought and high salinity. They are particularly well adapted to poor and disturbed soils thanks to their capacity to establish symbiotic associations with mycorrhizal fungi -both arbuscular and ectomycorrhizal- and with the nitrogen-fixing bacteria Frankia. These trees are now widely distributed in more than 20 African countries. Casuarina are mainly used in forestation programs to rehabilitate degraded or polluted sites, to stabilise sand dunes and to provide fuelwood and charcoal and thus contribute considerably to improving livelihoods and local economies. In this paper, we describe the geographical distribution of Casuarina in Africa, their economic and ecological value and the role of the symbiotic interactions between Casuarina, mycorrhizal fungi and Frankia.

  20. Casuarina in Africa: distribution, role and importance of arbuscular mycorrhizal, ectomycorrhizal fungi and Frankia on plant development.

    PubMed

    Diagne, Nathalie; Diouf, Diegane; Svistoonoff, Sergio; Kane, Aboubacry; Noba, Kandioura; Franche, Claudine; Bogusz, Didier; Duponnois, Robin

    2013-10-15

    Exotic trees were introduced in Africa to rehabilitate degraded ecosystems. Introduced species included several Australian species belonging to the Casuarinaceae family. Casuarinas trees grow very fast and are resistant to drought and high salinity. They are particularly well adapted to poor and disturbed soils thanks to their capacity to establish symbiotic associations with mycorrhizal fungi -both arbuscular and ectomycorrhizal- and with the nitrogen-fixing bacteria Frankia. These trees are now widely distributed in more than 20 African countries. Casuarina are mainly used in forestation programs to rehabilitate degraded or polluted sites, to stabilise sand dunes and to provide fuelwood and charcoal and thus contribute considerably to improving livelihoods and local economies. In this paper, we describe the geographical distribution of Casuarina in Africa, their economic and ecological value and the role of the symbiotic interactions between Casuarina, mycorrhizal fungi and Frankia. PMID:23747371

  1. Arbuscular mycorrhizal fungi alleviate oxidative stress induced by ADOR and enhance antioxidant responses of tomato plants.

    PubMed

    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.

  2. Arbuscular mycorrhizal fungi alleviate oxidative stress induced by ADOR and enhance antioxidant responses of tomato plants.

    PubMed

    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. PMID:24594394

  3. Arbuscular mycorrhizal fungi and rhizobium facilitate nitrogen uptake and transfer in soybean/maize intercropping system

    PubMed Central

    Meng, Lingbo; Zhang, Aiyuan; Wang, Fei; Han, Xiaoguang; Wang, Dejiang; Li, Shumin

    2015-01-01

    The tripartite symbiosis between legumes, rhizobia and mycorrhizal fungi are generally considered to be beneficial for the nitrogen (N) uptake of legumes, but the facilitation of symbiosis in legume/non-legume intercropping systems is not clear. Therefore, the aims of the research are as follows: (1) to verify if the dual inoculation can facilitate the N uptake and N transfer in maize/soybean intercropping systems and (2) to calculate how much N will be transferred from soybean to maize. A pot experiment with different root separations [solid barrier, mesh (30 μm) barrier and no barrier] was conducted, and the 15N isotopic tracing method was used to calculate how much N transferred from soybean to maize inoculated with arbuscular mycorrhizal fungi (AMF) and rhizobium in a soybean (Glycine max L.cv. Dongnong No. 42)/maize (Zea mays L.cv. Dongnong No. 48) intercropping system. Compared with the Glomus mosseae inoculation (G.m.), Rhizobium SH212 inoculation (SH212), no inoculation (NI), the dual inoculation (SH212+G.m.) increased the N uptake of soybean by 28.69, 39.58, and 93.07% in a solid barrier system. N uptake of maize inoculated with both G. mosseae and rhizobium was 1.20, 1.28, and 1.68 times more than that of G.m., SH212 and NI, respectively, in solid barrier treatments. In addition, the amount of N transferred from soybean to maize in a dual inoculation system with a mesh barrier was 7.25, 7.01, and 11.45 mg more than that of G.m., SH212 and NI and similarly, 6.40, 7.58, and 12.46 mg increased in no barrier treatments. Inoculating with both AMF and rhizobium in the soybean/maize intercropping system improved the N fixation efficiency of soybean and promoted N transfer from soybean to maize, resulting in the improvement of yield advantages of legume/non-legume intercropping. PMID:26029236

  4. Resistance Responses of Potato to Vesicular-Arbuscular Mycorrhizal Fungi under Varying Abiotic Phosphorus Levels 1

    PubMed Central

    McArthur, David A. J.; Knowles, N. Richard

    1992-01-01

    In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACCox) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis

  5. Water deficit improved the capacity of arbuscular mycorrhizal fungi (AMF) for inducing the accumulation of antioxidant compounds in lettuce leaves.

    PubMed

    Baslam, Marouane; Goicoechea, Nieves

    2012-07-01

    Lettuce, a major food crop within the European Union and the most used for the so-called 'Fourth Range' of vegetables, can associate with arbuscular mycorrhizal fungi (AMF). Mycorrhizal symbiosis can stimulate the synthesis of secondary metabolites, which may increase plant tolerance to stresses and enhance the accumulation of antioxidant compounds potentially beneficial to human health. Our objectives were to assess (1) if the application of a commercial formulation of AMF benefited growth of lettuce under different types and degrees of water deficits; (2) if water restrictions affected the nutritional quality of lettuce; and (3) if AMF improved the quality of lettuce when plants grew under reduced irrigation. Two cultivars of lettuce consumed as salads, Batavia Rubia Munguía and Maravilla de Verano, were used in the study. Four different water regimes were applied to both non-mycorrhizal and mycorrhizal plants: optimal irrigation (field capacity [FC]), a water regime equivalent to 2/3 of FC, a water regime equivalent to 1/2 of FC and a cyclic drought (CD). Results showed that mycorrhizal symbiosis improved the accumulation of antioxidant compounds, mainly carotenoids and anthocyanins, and to a lesser extent chlorophylls and phenolics, in leaves of lettuce. These enhancements were higher under water deficit than under optimal irrigation. Moreover, shoot biomass in mycorrhizal lettuces subjected to 2/3 of FC were similar to those of non-mycorrhizal plants cultivated under well-watered conditions. In addition, lettuces subjected to 2/3 FC had similar leaf RWC than their respective well-watered controls, regardless of mycorrhizal inoculation. Therefore, results suggest that mycorrhizal symbiosis can improve quality of lettuce and may allow restrict irrigation without reducing production.

  6. Gibberellins interfere with symbiosis signaling and gene expression and alter colonization by arbuscular mycorrhizal fungi in Lotus japonicus.

    PubMed

    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.

  7. Gibberellins Interfere with Symbiosis Signaling and Gene Expression and Alter Colonization by Arbuscular Mycorrhizal Fungi in Lotus japonicus1

    PubMed Central

    Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

    2015-01-01

    Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. PMID:25527715

  8. Organic fertilization changes the response of mycelium of arbuscular mycorrhizal fungi and their sporulation to mineral NPK supply.

    PubMed

    Gryndler, M; Hrselová, H; Vosátka, M; Votruba, J; Klír, J

    2001-01-01

    The synergetic effect of organic (cow manure) and mineral fertilization on the development arbuscular mycorrhizal (AM) fungi was demonstrated. The length of AM mycelium and sporulation were used as sensitive markers of the physiological state of soil AM fungal population. In manured treatments, both parameters increased in proportion with increasing mineral fertilization. In unmanured soil, the opposite trend was observed for the length of AM hyphae, which decreased with increasing mineral fertilization. Correlation analysis showed the dependence of length of AM hyphae and sporulation on soil available phosphorus. The correlation was negative in soil with no mineral fertilization and positive in soil supplied with luxury doses of mineral fertilizer. PMID:11898345

  9. Mitochondrial comparative genomics and phylogenetic signal assessment of mtDNA among arbuscular mycorrhizal fungi.

    PubMed

    Nadimi, Maryam; Daubois, Laurence; Hijri, Mohamed

    2016-05-01

    Mitochondrial (mt) genes, such as cytochrome C oxidase genes (cox), have been widely used for barcoding in many groups of organisms, although this approach has been less powerful in the fungal kingdom due to the rapid evolution of their mt genomes. The use of mt genes in phylogenetic studies of Dikarya has been met with success, while early diverging fungal lineages remain less studied, particularly the arbuscular mycorrhizal fungi (AMF). Advances in next-generation sequencing have substantially increased the number of publically available mtDNA sequences for the Glomeromycota. As a result, comparison of mtDNA across key AMF taxa can now be applied to assess the phylogenetic signal of individual mt coding genes, as well as concatenated subsets of coding genes. Here we show comparative analyses of publically available mt genomes of Glomeromycota, augmented with two mtDNA genomes that were newly sequenced for this study (Rhizophagus irregularis DAOM240159 and Glomus aggregatum DAOM240163), resulting in 16 complete mtDNA datasets. R. irregularis isolate DAOM240159 and G. aggregatum isolate DAOM240163 showed mt genomes measuring 72,293bp and 69,505bp with G+C contents of 37.1% and 37.3%, respectively. We assessed the phylogenies inferred from single mt genes and complete sets of coding genes, which are referred to as "supergenes" (16 concatenated coding genes), using Shimodaira-Hasegawa tests, in order to identify genes that best described AMF phylogeny. We found that rnl, nad5, cox1, and nad2 genes, as well as concatenated subset of these genes, provided phylogenies that were similar to the supergene set. This mitochondrial genomic analysis was also combined with principal coordinate and partitioning analyses, which helped to unravel certain evolutionary relationships in the Rhizophagus genus and for G. aggregatum within the Glomeromycota. We showed evidence to support the position of G. aggregatum within the R. irregularis 'species complex'. PMID:26868331

  10. The effect of different land uses on arbuscular mycorrhizal fungi in the northwestern Black Sea Region.

    PubMed

    Palta, Şahin; Lermi, Ayşe Genç; Beki, Rıdvan

    2016-06-01

    The object of the present research was to establish correlations between the status of root colonization of arbuscular mycorrhizal fungi (AMF) and different types of land use. In order to achieve this aim, rhizosphere soil samples from grassland crops were taken during June and July of 2013 in order to use for determining several soil characteristics. The 27 different taxa and 60 soil samples were collected from the rhizosphere level in the study areas. The existence of AMF was confirmed in 100 % of these plants with different rations of colonization (approximately 12-89 %). Bromus racemosus L. (pasture) was the most dense taxon with the percentage of AMF colonization of 88.9 %, and Trifolium pratense L. (forest) was the least dense taxon with the percentage of AMF colonization of 12.2 % (average 52.0 %). As a result of the statistical analysis, a positive relationship was found between the botanical composition of legumes and AMF colonization (r = 0.35; p = 0.006). However, a negative relationship was determined between botanical composition of other plant families and AMF colonization (r = -0.39; p = 0.002). In addition, a positive relationship was defined between soil pH (H2O) and the root colonization of AMF (r = 0.35; p = 0.005). The pasture had the highest mean value of AMF root colonization. However, the pasture and gap in the forest were in the same group, according to the results of the S-N-K test. PMID:27178052

  11. Do arbuscular mycorrhizal fungi affect cadmium uptake kinetics, subcellular distribution and chemical forms in rice?

    PubMed

    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. PMID:27450963

  12. Arbuscular Mycorrhizal Fungi as Natural Biofertilizers: Let's Benefit from Past Successes.

    PubMed

    Berruti, Andrea; Lumini, Erica; Balestrini, Raffaella; Bianciotto, Valeria

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) constitute a group of root obligate biotrophs that exchange mutual benefits with about 80% of plants. They are considered natural biofertilizers, since they provide the host with water, nutrients, and pathogen protection, in exchange for photosynthetic products. Thus, AMF are primary biotic soil components which, when missing or impoverished, can lead to a less efficient ecosystem functioning. The process of re-establishing the natural level of AMF richness can represent a valid alternative to conventional fertilization practices, with a view to sustainable agriculture. The main strategy that can be adopted to achieve this goal is the direct re-introduction of AMF propagules (inoculum) into a target soil. Originally, AMF were described to generally lack host- and niche-specificity, and therefore suggested as agriculturally suitable for a wide range of plants and environmental conditions. Unfortunately, the assumptions that have been made and the results that have been obtained so far are often worlds apart. The problem is that success is unpredictable since different plant species vary their response to the same AMF species mix. Many factors can affect the success of inoculation and AMF persistence in soil, including species compatibility with the target environment, the degree of spatial competition with other soil organisms in the target niche and the timing of inoculation. Thus, it is preferable to take these factors into account when "tuning" an inoculum to a target environment in order to avoid failure of the inoculation process. Genomics and transcriptomics have led to a giant step forward in the research field of AMF, with consequent major advances in the current knowledge on the processes involved in their interaction with the host-plant and other soil organisms. The history of AMF applications in controlled and open-field conditions is now long. A review of biofertilization experiments, based on the use of AMF, has here

  13. Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions.

    PubMed

    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.

  14. Does Wheat Genetically Modified for Disease Resistance Affect Root-Colonizing Pseudomonads and Arbuscular Mycorrhizal Fungi?

    PubMed Central

    Foetzki, Andrea; Luginbühl, Carolin; Winzeler, Michael; Kneubühler, Yvan; Matasci, Caterina; Mascher-Frutschi, Fabio; Kalinina, Olena; Boller, Thomas; Keel, Christoph; Maurhofer, Monika

    2013-01-01

    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. PMID:23372672

  15. Prunus persica Crop Management Differentially Promotes Arbuscular Mycorrhizal Fungi Diversity in a Tropical Agro-Ecosystem

    PubMed Central

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

    2014-01-01

    Due to the important role of arbuscular mycorrhizal fungi (AMF) in ecosystem functioning, determination of the effect of management practices on the AMF diversity in agricultural soils is essential for the sustainability of these agro-ecosystems. The objective of this study was to compare the AMF diversity in Prunus persica roots under two types of fertilisation (inorganic, with or without manure) combined with integrated or chemical pest management in a Venezuelan agro-ecosystem. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty-one different phylotypes were identified: 15 belonged to the genus Glomus, one to Claroideoglomus, two to Paraglomus, one to Acaulospora, one to Scutellospora and one to Archaeospora. The distribution of the AMF community composition differed as a consequence of the treatment effects. The treatment combining organic and inorganic fertilisation with chemical pest control had the highest AMF richness and the treatment combining inorganic fertilisation with chemical pest had the lowest. The real causes and effects of these differences in the AMF community are very difficult to establish, since the crop management regimes tested were composed of several interacting factors. In conclusion, the crop management practices can exert a significant influence on the populations of AMF. The treatment combining organic and inorganic fertilisation with chemical pest control appears to be the most suitable agricultural management strategy with respect to improving the AMF diversity in this crop under tropical conditions, and thus for maintaining the agricultural and environmental sustainability of this agro-ecosystem. PMID:24520389

  16. Intraisolate Mitochondrial Genetic Polymorphism and Gene Variants Coexpression in Arbuscular Mycorrhizal Fungi

    PubMed Central

    Beaudet, Denis; de la Providencia, Ivan Enrique; Labridy, Manuel; Roy-Bolduc, Alice; Daubois, Laurence; Hijri, Mohamed

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are multinucleated and coenocytic organisms, in which the extent of the intraisolate nuclear genetic variation has been a source of debate. Conversely, their mitochondrial genomes (mtDNAs) have appeared to be homogeneous within isolates in all next generation sequencing (NGS)-based studies. Although several lines of evidence have challenged mtDNA homogeneity in AMF, extensive survey to investigate intraisolate allelic diversity has not previously been undertaken. In this study, we used a conventional polymerase chain reaction -based approach on selected mitochondrial regions with a high-fidelity DNA polymerase, followed by cloning and Sanger sequencing. Two isolates of Rhizophagus irregularis were used, one cultivated in vitro for several generations (DAOM-197198) and the other recently isolated from the field (DAOM-242422). At different loci in both isolates, we found intraisolate allelic variation within the mtDNA and in a single copy nuclear marker, which highlighted the presence of several nonsynonymous mutations in protein coding genes. We confirmed that some of this variation persisted in the transcriptome, giving rise to at least four distinct nad4 transcripts in DAOM-197198. We also detected the presence of numerous mitochondrial DNA copies within nuclear genomes (numts), providing insights to understand this important evolutionary process in AMF. Our study reveals that genetic variation in Glomeromycota is higher than what had been previously assumed and also suggests that it could have been grossly underestimated in most NGS-based AMF studies, both in mitochondrial and nuclear genomes, due to the presence of low-level mutations. PMID:25527836

  17. Prunus persica crop management differentially promotes arbuscular mycorrhizal fungi diversity in a tropical agro-ecosystem.

    PubMed

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

    2014-01-01

    Due to the important role of arbuscular mycorrhizal fungi (AMF) in ecosystem functioning, determination of the effect of management practices on the AMF diversity in agricultural soils is essential for the sustainability of these agro-ecosystems. The objective of this study was to compare the AMF diversity in Prunus persica roots under two types of fertilisation (inorganic, with or without manure) combined with integrated or chemical pest management in a Venezuelan agro-ecosystem. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty-one different phylotypes were identified: 15 belonged to the genus Glomus, one to Claroideoglomus, two to Paraglomus, one to Acaulospora, one to Scutellospora and one to Archaeospora. The distribution of the AMF community composition differed as a consequence of the treatment effects. The treatment combining organic and inorganic fertilisation with chemical pest control had the highest AMF richness and the treatment combining inorganic fertilisation with chemical pest had the lowest. The real causes and effects of these differences in the AMF community are very difficult to establish, since the crop management regimes tested were composed of several interacting factors. In conclusion, the crop management practices can exert a significant influence on the populations of AMF. The treatment combining organic and inorganic fertilisation with chemical pest control appears to be the most suitable agricultural management strategy with respect to improving the AMF diversity in this crop under tropical conditions, and thus for maintaining the agricultural and environmental sustainability of this agro-ecosystem.

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

    PubMed

    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. PMID:18624242

  19. Molecular biodiversity of arbuscular mycorrhizal fungi in trace metal-polluted soils.

    PubMed

    Hassan, Saad El Din; Boon, Eva; St-Arnaud, Marc; Hijri, Mohamed

    2011-08-01

    We assessed the indigenous arbuscular mycorrhizal fungi (AMF) community structure from the roots and associated soil of Plantago major (plantain) plants growing on sites polluted with trace metals (TM) and on unpolluted sites. Uncontaminated and TM-contaminated sites containing As, Cd, Cu, Pb, Sn and Zn were selected based on a survey of the TM concentration in soils of community gardens in the City of Montréal. Total genomic DNA was extracted directly from these samples. PCR followed by denaturing gradient gel electrophoresis (PCR-DGGE), augmented by cloning and sequencing, as well as direct sequencing techniques, was all used to investigate AMF community structure. We found a decreased diversity of native AMF (assessed by the number of AMF ribotypes) in soils and plant roots harvested from TM-polluted soils compared with unpolluted soils. We also found that community structure was modified by TM contamination. Various species of Glomus, Scutellospora aurigloba and S. calospora were the most abundant ribotypes detected in unpolluted soil; ribotypes of G. etunicatum, G. irregulare/G. intraradices and G. viscosum were found in both polluted and unpolluted soils, while ribotypes of G. mosseae and Glomus spp. (B9 and B13) were dominant in TM-polluted soils. The predominance of G. mosseae in metal-polluted sites suggests the tolerance of this species to TM stress, as well as its potential use for phytoremediation. These data are relevant for our understanding of how AMF microbial communities respond to natural environments that contain a broad variety of toxic inorganic compounds and will substantially expand our knowledge of AMF ecology and biodiversity. PMID:21668808

  20. Do arbuscular mycorrhizal fungi affect cadmium uptake kinetics, subcellular distribution and chemical forms in rice?

    PubMed

    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.

  1. Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions

    PubMed Central

    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

  2. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    PubMed

    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. Sheared-Root Inocula of Vesicular-Arbuscular Mycorrhizal Fungi

    PubMed Central

    Sylvia, D. M.; Jarstfer, A. G.

    1992-01-01

    For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 μm, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material-1. Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4°C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies. PMID:16348622

  4. Changes in communities of Fusarium and arbuscular mycorrhizal fungi as related to different asparagus cultural factors.

    PubMed

    Yergeau, Etienne; Vujanovic, Vladimir; St-Arnaud, Marc

    2006-07-01

    Asparagus (Asparagus officinalis) is a high-value perennial vegetable crop that has shown a marked decline in productivity after many years of continuous harvesting. This decline is caused by an increase in both abiotic (autotoxicity, harvesting pressure) and biotic stresses [fungal infections, mainly Fusarium crown and root rot (FCRR)]. To gain insight into disease development and possible mitigation strategies, we studied the effects of harvesting, time in the growing season, and field age on FCRR development, Fusarium species composition, and arbuscular mycorrhizal fungi (AMF) communities in both a controlled field experiment and an ecological survey of commercial fields. In one experiment, a 3-year-old asparagus field was subdivided into plots that were harvested or not and sampled throughout the growing season to assess short-term dominant Fusarium species shifts. In addition, diseased and healthy asparagus plants sampled from six commercial fields in the same geographical region were used to assess Fusarium and AMF communities in relation to different parameters. Fusarium and AMF communities were described by using a polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) approach, and results were analyzed by mainly correspondence analysis and canonical correspondence analysis. Results showed that dominant Fusarium taxa assemblages changed throughout the growing season. Harvested plots had significantly more FCRR symptomatic plants at the end of the growing season, but this effect was not related with any trend in Fusarium community structure. Sampling site and plant age significantly influenced AMF community structure, whereas only sampling site consistently influenced the Fusarium community. Diseased and healthy plants harbored similar Fusarium and AMF communities. Shifts in Fusarium community might not be responsible for different disease incidence because they are ubiquitous regardless of plant health status or harvesting regime

  5. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    PubMed

    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. PMID:27197388

  6. Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions.

    PubMed

    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

  7. The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil.

    PubMed

    Yang, Yurong; Liang, Yan; Han, Xiaozhen; Chiu, Tsan-Yu; Ghosh, Amit; Chen, Hui; Tang, Ming

    2016-02-04

    Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.

  8. The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil.

    PubMed

    Yang, Yurong; Liang, Yan; Han, Xiaozhen; Chiu, Tsan-Yu; Ghosh, Amit; Chen, Hui; Tang, Ming

    2016-01-01

    Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation. PMID:26842958

  9. The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

    PubMed Central

    Yang, Yurong; Liang, Yan; Han, Xiaozhen; Chiu, Tsan-Yu; Ghosh, Amit; Chen, Hui; Tang, Ming

    2016-01-01

    Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation. PMID:26842958

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

    PubMed

    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.

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

    PubMed

    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. PMID:25495930

  12. Possible evidence for contribution of arbuscular mycorrhizal fungi (AMF) in phytoremediation of iron-cyanide (Fe-CN) complexes.

    PubMed

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

    2016-08-01

    Arbuscular mycorrhizal fungi (AMF) are integral functioning parts of plant root systems and are widely recognized for enhancing contaminants uptake and metabolism on severely disturbed sites. However, the patterns of their influence on the phytoremediation of iron-cyanide (Fe-CN) complexes are unknown. Fe-CN complexes are of great common interest, as iron is one of the most abundant element in soil and water. Effect of ryegrass (Lolium perenne L.) roots inoculation, using mycorrhizal fungi (Rhizophagus irregularis and a mixture of R. irregularis, Funneliformis mosseae, Rhizophagus aggregatus, and Claroideoglomus etunicatum), on iron-cyanide sorption was studied. Results indicated significantly higher colonization of R. irregularis than the mixture of AMF species on ryegrass roots. Series of batch experiments using potassium hexacyanoferrate (II) solutions, in varying concentrations revealed significantly higher reduction of total CN and free CN content in the mycorrhizal roots, indicating greater cyanide decrease in the treatment inoculated with R. irregularis. Our study is a first indication of the possible positive contribution of AM fungi on the phytoremediation of iron-cyanide complexes. PMID:27256319

  13. Possible evidence for contribution of arbuscular mycorrhizal fungi (AMF) in phytoremediation of iron-cyanide (Fe-CN) complexes.

    PubMed

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

    2016-08-01

    Arbuscular mycorrhizal fungi (AMF) are integral functioning parts of plant root systems and are widely recognized for enhancing contaminants uptake and metabolism on severely disturbed sites. However, the patterns of their influence on the phytoremediation of iron-cyanide (Fe-CN) complexes are unknown. Fe-CN complexes are of great common interest, as iron is one of the most abundant element in soil and water. Effect of ryegrass (Lolium perenne L.) roots inoculation, using mycorrhizal fungi (Rhizophagus irregularis and a mixture of R. irregularis, Funneliformis mosseae, Rhizophagus aggregatus, and Claroideoglomus etunicatum), on iron-cyanide sorption was studied. Results indicated significantly higher colonization of R. irregularis than the mixture of AMF species on ryegrass roots. Series of batch experiments using potassium hexacyanoferrate (II) solutions, in varying concentrations revealed significantly higher reduction of total CN and free CN content in the mycorrhizal roots, indicating greater cyanide decrease in the treatment inoculated with R. irregularis. Our study is a first indication of the possible positive contribution of AM fungi on the phytoremediation of iron-cyanide complexes.

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

    PubMed

    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. PMID:16989281

  15. Arbuscular mycorrhizal fungi diversity influenced by different agricultural management practices in a semi-arid Mediterranean agro-ecosystem

    NASA Astrophysics Data System (ADS)

    de Mar Alguacil, Maria; Torrecillas, Emma; Garcia-Orenes, Fuensanta; Torres, Maria Pilar; Roldan, Antonio

    2013-04-01

    The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study a field experiment was performed at the El Teularet-Sierra de Enguera Experimental Station (eastern Spain) to assess the influence during a 6-yr period of different agricultural practices on the diversity of arbuscular mycorrhizal fungi (AMF). The management practices included residual herbicide use, ploughing, ploughing + oats, addition of oat straw mulch and a control (land abandonment). Adjacent soil under natural vegetation was used as a reference for local, high-quality soil and as a control for comparison with the agricultural soils under different management practices. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Thirty-six different phylotypes were identified, which were grouped in four families: Glomeraceae, Paraglomeraceae, Ambisporaceae and Claroideoglomeraceae. The first results showed significant differences in the distribution of the AMF phylotypes as consequence of the difference between agricultural management practices. Thus, the lowest diversity was observed for the plot that was treated with herbicide. The management practices including ploughing and ploughing + oats had similar AMF diversity. Oat straw mulching yielded the highest number of different AMF sequence types and showed the highest diversity index. Thus, this treatment could be more suitable in sustainable soil use and therefore protection of biodiversity.

  16. Saprobe fungi decreased the sensitivity to the toxic effect of dry olive mill residue on arbuscular mycorrhizal plants.

    PubMed

    Sampedro, I; Aranda, E; Díaz, R; García-Sanchez, M; Ocampo, J A; García-Romera, I

    2008-02-01

    We studied the influence of olive mill dry residue (DOR) treated with saprobe fungi on growth of tomato and alfalfa colonized by Glomus deserticola. The application of 25g kg(-1) of dry DOR to soil decreased the shoot and root dry weight of tomato and alfalfa. Plants were more sensitive to the toxicity of DOR when colonized with the arbuscular mycorrhizal (AM) fungi. The sensitivity of both plants to the toxicity of DOR differed according to whether they were colonized by G. deserticola or by indigenous AM fungi. The phytotoxicity of DOR towards tomato and alfalfa was decreased by incubation the residue before planting with saprobe fungi for 20wk. The beneficial effects of AM fungi on plant growth added with DOR incubated with saprobe fungi depend of the type of the plant and AM fungi. The contribution of AM fungi to the beneficial effect of DOR incubated with saprobe fungi varied according to the type of the plant and AM fungi. G. deserticola increased the shoot and root dry weight of plants when they were grown in the presence of DOR incubated with saprobe fungi for 20wk. The beneficial effect of saprobe fungi on the dry weight and the level of AM mycorrhization of plants seem to be related to the decrease caused by these fungi in the phenol concentration in DOR. However, the toxicity of DOR due to substances other than phenols can not be ignored. The use of certain saprobe and AM fungi allows the possibility of using DOR as an organic fertilizer.

  17. Saprobe fungi decreased the sensitivity to the toxic effect of dry olive mill residue on arbuscular mycorrhizal plants.

    PubMed

    Sampedro, I; Aranda, E; Díaz, R; García-Sanchez, M; Ocampo, J A; García-Romera, I

    2008-02-01

    We studied the influence of olive mill dry residue (DOR) treated with saprobe fungi on growth of tomato and alfalfa colonized by Glomus deserticola. The application of 25g kg(-1) of dry DOR to soil decreased the shoot and root dry weight of tomato and alfalfa. Plants were more sensitive to the toxicity of DOR when colonized with the arbuscular mycorrhizal (AM) fungi. The sensitivity of both plants to the toxicity of DOR differed according to whether they were colonized by G. deserticola or by indigenous AM fungi. The phytotoxicity of DOR towards tomato and alfalfa was decreased by incubation the residue before planting with saprobe fungi for 20wk. The beneficial effects of AM fungi on plant growth added with DOR incubated with saprobe fungi depend of the type of the plant and AM fungi. The contribution of AM fungi to the beneficial effect of DOR incubated with saprobe fungi varied according to the type of the plant and AM fungi. G. deserticola increased the shoot and root dry weight of plants when they were grown in the presence of DOR incubated with saprobe fungi for 20wk. The beneficial effect of saprobe fungi on the dry weight and the level of AM mycorrhization of plants seem to be related to the decrease caused by these fungi in the phenol concentration in DOR. However, the toxicity of DOR due to substances other than phenols can not be ignored. The use of certain saprobe and AM fungi allows the possibility of using DOR as an organic fertilizer. PMID:17980897

  18. The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

    DOE PAGES

    Yang, Yurong; Liang, Yan; Han, Xiaozhen; Chiu, Tsan-Yu; Ghosh, Amit; Chen, Hui; Tang, Ming

    2016-02-04

    Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. Here, our study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizalmore » legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.« less

  19. Arbuscular mycorrhizal fungi can alleviate the adverse effects of chlorothalonil on Oryza sativa L.

    PubMed

    Zhang, Xu-Hong; Zhu, Yong-Guan; Lin, Ai-Jun; Chen, Bao-Dong; Smith, Sally E; Smith, F Andrew

    2006-09-01

    A glasshouse pot experiment was conducted to investigate the effect of the fungicide chlorothalonil on the growth of upland rice, in the absence or presence of the arbuscular mycorrhizal fungus (AMF) Glomus mosseae (NM and GM treatments). The plants were grown with three concentrations of chlorothalonil (0, 50 and 100 mg kg(-1) soil). Mycorrhizal colonization decreased significantly with increasing chlorothalonil concentrations. Plant biomass decreases were smaller in GM plants than in non-mycorrhizal (NM) plants. Mycorrhizal dependency was the highest with 50 mg kg(-1) chlorothalonil. Chlorothalonil affected physiological processes in upland rice irrespective of inoculation. Chlorothalonil at 50 and 100 mg kg(-1) increased ascorbate peroxidase (APX) activity and soluble protein concentrations in shoots and roots of NM upland rice. However, values of APX, catalase (CAT) and peroxidase (POD) were reduced more in GM plants than in NM plants. These results showed that chlorothalonil induced oxidative stress in upland rice and it is needed to evaluate the side effects of chlorothalonil on rice and AMF.

  20. Carlactone-type strigolactones and their synthetic analogues as inducers of hyphal branching in arbuscular mycorrhizal fungi.

    PubMed

    Mori, Narumi; Nishiuma, Kenta; Sugiyama, Takuya; Hayashi, Hideo; Akiyama, Kohki

    2016-10-01

    Hyphal branching in the vicinity of host roots is a host recognition response of arbuscular mycorrhizal fungi. This morphological event is elicited by strigolactones. Strigolactones are carotenoid-derived terpenoids that are synthesized from carlactone and its oxidized derivatives. To test the possibility that carlactone and its oxidized derivatives might act as host-derived precolonization signals in arbuscular mycorrhizal symbiosis, carlactone, carlactonoic acid, and methyl carlactonoate as well as monohydroxycarlactones, 4-, 18-, and 19-hydroxycarlactones, were synthesized chemically and evaluated for hyphal branching-inducing activity in germinating spores of the arbuscular mycorrhizal fungus Gigaspora margarita. Hyphal branching activity was found to correlate with the degree of oxidation at C-19 methyl. Carlactone was only weakly active (100 ng/disc), whereas carlactonoic acid showed comparable activity to the natural canonical strigolactones such as strigol and sorgomol (100 pg/disc). Hydroxylation at either C-4 or C-18 did not significantly affect the activity. A series of carlactone analogues, named AD ester and AA'D diester, was synthesized by reacting formyl Meldrum's acid with benzyl, cyclohexylmethyl, and cyclogeranyl alcohols (the A-ring part), followed by coupling of the potassium enolates of the resulting formylacetic esters with the D-ring butenolide. AD ester analogues exhibited moderate activity (1 ng-100 pg/disc), while AA'D diester analogues having cyclohexylmethyl and cyclogeranyl groups were highly active on the AM fungus (10 pg/disc). These results indicate that the oxidation of methyl to carboxyl at C-19 in carlactone is a prerequisite but BC-ring formation is not essential to show hyphal branching activity comparable to that of canonical strigolactones.

  1. [Effects of arbuscular mycorrhizal fungi on the vegetation restoration of different types of coal mine spoil banks].

    PubMed

    Zhao, Ren-Xin; Guo, Wei; Fu, Rui-Ying; Zhao, Wen-Jing; Guo, Jiang-Yuan; Bi, Na; Zhang, Jun

    2013-11-01

    A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus etunicatum (GE) and Glomus versiforme (GV) on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals by maize (Zea mays L.) grown in three types of coal mine spoil banks. The aim was to provide a technical basis for the revegetation of coal mine spoil banks in grassland ecosystem. The results indicated that the symbiotic associations were successfully established between two isolates and maize grown in the three substrates, with an average mycorrhizal colonization rate ranging from 36% to 54%. The colonization of two AM fungi significantly increased the dry weight of maize grown in recent discharged and weathered coal mine spoils and GE increased those grown in weathered coal mine spoil. Inoculation with AM fungi promoted the uptake of N, P and K by maize to varying degrees. In addition, inoculation with GE and GV also decreased C: N: P ratios, supporting the growth rate hypothesis, and had significantly differences on concentrations of Cu, Fe, Mn and Zn in shoots and roots of maize. The results indicated that GE and GV had different mycorrhizal effects on maize in the three types of substrates. GV was more suitable for the revegetation of recent discharged coal mine spoil and weathered coal mine spoil, while GE was more suitable for the revegetation of spontaneous combusted coal mine spoil. The experiment demonstrates that AM fungi have a potential role for maize to enhance the ability to adapt the composite adversity of different types of coal mine spoil and play a positive role in the revegetation of different coal mine spoil banks. Further field experiments should be conducted to evaluate the practical effects of AM fungi on the vegetation restoration of different types of coal mine spoil under field conditions.

  2. A molecular approach to study the arbuscular mycorrhizal fungi community in a typical Piedmont grapevine cultivar

    NASA Astrophysics Data System (ADS)

    Magurno, F.; Bughi Peruglia, G.; Lumini, E.; Bianciotto, V.; Balestrini, R.

    2009-04-01

    Viticulture and wine production represent one of the most relevant agro-food sectors for the Piedmont Region (Italy) in terms of value, with more than 400 millions € a year (12 % of total agricultural production of the Region and the 10 % of the national grape and wine production). The soil where grapevines (Vitis spp.) grow is one of the first parameters influencing the complex grapevine-wine chain. Arbuscular mycorrhizal fungi (AMFs), a main component of soil microbiota in most agrosystems, are considered crucial biomarkers of soil quality because of their biofertilisers role. As mutualistic symbionts, they colonize the roots of the majority of plants. Benefits in symbiosis are well showed as an improvement in shoot/root growth, mineral transport, water-stress tolerance and resistance to certain diseases. Grapevines roots are often heavily colonized by AMFs under field conditions and in some cases AMFs appear to be necessary for their normal growth and survival. Even so, little information are until now available about composition of AMFs communities living in the vineyards soil and in associations with grapevine roots, mainly related to morphological characterization. Vineyard of Nebbiolo, one of the most important Piedmont cultivar, was selected in order to study the AMFs community using a molecular approach. Soil samples and roots from an experimental vineyard located in Lessona (Biella, Piedmont, Italy) were analyzed using AM fungal-specific primers to partially amplify the small subunit (SSU) of the ribosomal DNA genes. Much more than 650 clones were sequenced. Phylogenetic analyses identified 32 OTUs from soil, clustered into Glomus groups Aa, Ab, Ad and B, Diversisporaceae and Gigasporaceae families. Thirteen OTUs from roots were determined, clustered into Glomus groups Ab, Ad and B, and Gigasporaceae family. In particular, Glomus group Ad was the best represented in both compartments, suggesting a correlation between intra and extra radical communities

  3. Arbuscular Mycorrhizal Fungi as Natural Biofertilizers: Let's Benefit from Past Successes.

    PubMed

    Berruti, Andrea; Lumini, Erica; Balestrini, Raffaella; Bianciotto, Valeria

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) constitute a group of root obligate biotrophs that exchange mutual benefits with about 80% of plants. They are considered natural biofertilizers, since they provide the host with water, nutrients, and pathogen protection, in exchange for photosynthetic products. Thus, AMF are primary biotic soil components which, when missing or impoverished, can lead to a less efficient ecosystem functioning. The process of re-establishing the natural level of AMF richness can represent a valid alternative to conventional fertilization practices, with a view to sustainable agriculture. The main strategy that can be adopted to achieve this goal is the direct re-introduction of AMF propagules (inoculum) into a target soil. Originally, AMF were described to generally lack host- and niche-specificity, and therefore suggested as agriculturally suitable for a wide range of plants and environmental conditions. Unfortunately, the assumptions that have been made and the results that have been obtained so far are often worlds apart. The problem is that success is unpredictable since different plant species vary their response to the same AMF species mix. Many factors can affect the success of inoculation and AMF persistence in soil, including species compatibility with the target environment, the degree of spatial competition with other soil organisms in the target niche and the timing of inoculation. Thus, it is preferable to take these factors into account when "tuning" an inoculum to a target environment in order to avoid failure of the inoculation process. Genomics and transcriptomics have led to a giant step forward in the research field of AMF, with consequent major advances in the current knowledge on the processes involved in their interaction with the host-plant and other soil organisms. The history of AMF applications in controlled and open-field conditions is now long. A review of biofertilization experiments, based on the use of AMF, has here

  4. Arbuscular Mycorrhizal Fungi as Natural Biofertilizers: Let's Benefit from Past Successes

    PubMed Central

    Berruti, Andrea; Lumini, Erica; Balestrini, Raffaella; Bianciotto, Valeria

    2016-01-01

    Arbuscular Mycorrhizal Fungi (AMF) constitute a group of root obligate biotrophs that exchange mutual benefits with about 80% of plants. They are considered natural biofertilizers, since they provide the host with water, nutrients, and pathogen protection, in exchange for photosynthetic products. Thus, AMF are primary biotic soil components which, when missing or impoverished, can lead to a less efficient ecosystem functioning. The process of re-establishing the natural level of AMF richness can represent a valid alternative to conventional fertilization practices, with a view to sustainable agriculture. The main strategy that can be adopted to achieve this goal is the direct re-introduction of AMF propagules (inoculum) into a target soil. Originally, AMF were described to generally lack host- and niche-specificity, and therefore suggested as agriculturally suitable for a wide range of plants and environmental conditions. Unfortunately, the assumptions that have been made and the results that have been obtained so far are often worlds apart. The problem is that success is unpredictable since different plant species vary their response to the same AMF species mix. Many factors can affect the success of inoculation and AMF persistence in soil, including species compatibility with the target environment, the degree of spatial competition with other soil organisms in the target niche and the timing of inoculation. Thus, it is preferable to take these factors into account when “tuning” an inoculum to a target environment in order to avoid failure of the inoculation process. Genomics and transcriptomics have led to a giant step forward in the research field of AMF, with consequent major advances in the current knowledge on the processes involved in their interaction with the host-plant and other soil organisms. The history of AMF applications in controlled and open-field conditions is now long. A review of biofertilization experiments, based on the use of AMF, has

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

    PubMed

    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 < 0.05). Plant richness and pH were linked to the community composition of 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 < 0.05). The results suggested that abundance of AM fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration.

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

    PubMed

    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 < 0.05). Plant richness and pH were linked to the community composition of 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 < 0.05). The results suggested that abundance of AM fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration. PMID:27287492

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

    PubMed

    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.

  8. Community Analysis of Arbuscular Mycorrhizal Fungi in Roots of Poncirus trifoliata and Citrus reticulata Based on SSU rDNA

    PubMed Central

    Wang, Yin

    2014-01-01

    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. PMID:25162057

  9. Community analysis of arbuscular mycorrhizal fungi in roots of Poncirus trifoliata and Citrus reticulata based on SSU rDNA.

    PubMed

    Wang, Peng; Wang, Yin

    2014-01-01

    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. PMID:25162057

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

    PubMed

    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. PMID:27077274

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

    PubMed

    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.

  12. Molecular community analysis of arbuscular mycorrhizal fungi in roots of geothermal soils in Yellowstone National Park (USA).

    PubMed

    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.

  13. [Effects of Arbuscular Mycorrhizal Fungi on the Growth and Ce Uptake of Maize Grown in Ce-contaminated Soils].

    PubMed

    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. PMID

  14. [Effects of Arbuscular Mycorrhizal Fungi on the Growth and Ce Uptake of Maize Grown in Ce-contaminated Soils].

    PubMed

    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.

  15. Transformation and Immobilization of Chromium by Arbuscular Mycorrhizal Fungi as Revealed by SEM-EDS, TEM-EDS, and XAFS.

    PubMed

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

    2015-12-15

    Arbuscular mycorrhizal fungi (AMF), ubiquitous soil fungi that form symbiotic relationships with the majority of terrestrial plants, are known to play an important role in plant tolerance to chromium (Cr) contamination. However, the underlying mechanisms, especially the direct influences of AMF on the translocation and transformation of Cr in the soil-plant continuum, are still unresolved. In a two-compartment root-organ cultivation system, the extraradical mycelium (ERM) of mycorrhizal roots was treated with 0.05 mmol L(-1) Cr(VI) for 12 days to investigate the uptake, translocation, and transformation of Cr(VI) by AMF using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS), transmission electron microscopy equipped with energy-dispersive spectroscopy (TEM-EDS), and X-ray-absorption fine structure (XAFS) technologies. The results indicated that AMF can immobilize quantities of Cr via reduction of Cr(VI) to Cr(III), forming Cr(III)-phosphate analogues, likely on the fungal surface. Besides this, we also confirmed that the extraradical mycelium (ERM) can actively take up Cr [either in the form of Cr(VI) or Cr(III)] and transport Cr [potentially in the form of Cr(III)-histidine analogues] to mycorrhizal roots but immobilize most of the Cr(III) in the fungal structures. Based on an X-ray absorption near-edge spectroscopy analysis of Cr(VI)-treated roots, we proposed that the intraradical fungal structures can also immobilize Cr within mycorrhizal roots. Our findings confirmed the immobilization of Cr by AMF, which plays an essential role in the Cr(VI) tolerance of AM symbioses.

  16. Transformation and Immobilization of Chromium by Arbuscular Mycorrhizal Fungi as Revealed by SEM-EDS, TEM-EDS, and XAFS.

    PubMed

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

    2015-12-15

    Arbuscular mycorrhizal fungi (AMF), ubiquitous soil fungi that form symbiotic relationships with the majority of terrestrial plants, are known to play an important role in plant tolerance to chromium (Cr) contamination. However, the underlying mechanisms, especially the direct influences of AMF on the translocation and transformation of Cr in the soil-plant continuum, are still unresolved. In a two-compartment root-organ cultivation system, the extraradical mycelium (ERM) of mycorrhizal roots was treated with 0.05 mmol L(-1) Cr(VI) for 12 days to investigate the uptake, translocation, and transformation of Cr(VI) by AMF using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS), transmission electron microscopy equipped with energy-dispersive spectroscopy (TEM-EDS), and X-ray-absorption fine structure (XAFS) technologies. The results indicated that AMF can immobilize quantities of Cr via reduction of Cr(VI) to Cr(III), forming Cr(III)-phosphate analogues, likely on the fungal surface. Besides this, we also confirmed that the extraradical mycelium (ERM) can actively take up Cr [either in the form of Cr(VI) or Cr(III)] and transport Cr [potentially in the form of Cr(III)-histidine analogues] to mycorrhizal roots but immobilize most of the Cr(III) in the fungal structures. Based on an X-ray absorption near-edge spectroscopy analysis of Cr(VI)-treated roots, we proposed that the intraradical fungal structures can also immobilize Cr within mycorrhizal roots. Our findings confirmed the immobilization of Cr by AMF, which plays an essential role in the Cr(VI) tolerance of AM symbioses. PMID:26551890

  17. Deficit irrigation promotes arbuscular colonization of fine roots by mycorrhizal fungi in grapevines (Vitis vinifera L.) in an arid climate.

    PubMed

    Schreiner, R Paul; Tarara, Julie M; Smithyman, Russell P

    2007-10-01

    Regulated deficit irrigation (RDI) is a common practice applied in irrigated vineyards to control canopy growth and improve fruit quality, but little is known of how imposed water deficits may alter root growth and colonization by beneficial arbuscular mycorrhizal fungi (AMF). Thus, root growth and mycorrhizal colonization were determined throughout the growing season for 3 years in own-rooted, field-grown, 'Cabernet Sauvignon' grapevines exposed to three RDI treatments. Vines under standard RDI were irrigated at 60 to 70% of full-vine evapotranspiration (FVET) from 2 weeks after fruit set until harvest, a standard commercial practice. Early deficit vines were exposed to a more extreme deficit (30% FVET) during the period from 2 weeks after fruit set until the commencement of ripening (veraison), and thereafter reverted to standard RDI. Late deficit vines were under standard RDI until veraison, then exposed to a more extreme deficit (30% FVET) between veraison and harvest. The production of fine roots was reduced in both the early and late deficit treatments, but the reduction was more consistent in the early deficit vines because the additional deficit was imposed when roots were more rapidly growing. The frequency of arbuscules in fine roots was greater in both of the additional deficit treatments than in the standard RDI, a response that appeared chronic, as the higher frequency of arbuscules was observed throughout the season despite the additional deficits being applied at discrete times. It appears that grapevines compensated for a lower density of fine roots by stimulating arbuscular colonization. Irrigation did not affect yield or quality of grapes, but reduced whole-vine photosynthesis during the additional deficit periods. It appears that high-quality grapes can be produced in this region with less water than that applied under the current RDI practice because the root system of the vine may be more efficient due to greater arbuscular colonization by AMF

  18. Contribution of the saprobic fungi Trametes versicolor and Trichoderma harzianum and the arbuscular mycorrhizal fungi Glomus deserticola and G. claroideum to arsenic tolerance of Eucalyptus globulus.

    PubMed

    Arriagada, C; Aranda, E; Sampedro, I; Garcia-Romera, I; Ocampo, J A

    2009-12-01

    The presence of high concentrations of arsenic (As) decreased the shoot and root dry weight, chlorophyll and P and Mg content of Eucalyptus globulus colonized with the arbuscular mycorrhizal (AM) fungi Glomus deserticola or G. claroideum, but these parameters were higher than in non-AM plants. As increased the percentage of AM length colonization and succinate dehydrogenase (SDH) activity in the root of E. globulus. Trichoderma harzianum, but not Trametes versicolor, increased the shoot and root dry weight, chlorophyll content, the percentage of AM root length colonization and SDH activity of E. globulus in presence of all As concentrations applied to soil when was inoculated together with G. claroideum. AM fungi increased shoot As and P concentration of E. globulus to higher level than the non-AM inoculated controls. The contribution of the AM and saprobe fungi to the translocation of As from root to shoot of E. globulus is discussed.

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

    PubMed

    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.

  20. Inoculation of Woody Legumes with Selected Arbuscular Mycorrhizal Fungi and Rhizobia To Recover Desertified Mediterranean Ecosystems

    PubMed Central

    Herrera, M. A.; Salamanca, C. P.; Barea, J. M.

    1993-01-01

    Revegetation strategies, either for reclamation or for rehabilitation, are being used to recover desertified ecosystems. Woody legumes are recognized as species that are useful for revegetation of water-deficient, low-nutrient environments because of their ability to form symbiotic associations with rhizobial bacteria and mycorrhizal fungi, which improve nutrient acquisition and help plants to become established and cope with stress situations. A range of woody legumes used in revegetation programs, particularly in Mediterranean regions, were assayed. These legumes included both exotic and native species and were used in a test of a desertified semiarid ecosystem in southeast Spain. Screening for the appropriate plant species-microsymbiont combinations was performed previously, and a simple procedure to produce plantlets with optimized mycorrhizal and nodulated status was developed. The results of a 4-year trial showed that (i) only the native shrub legumes were able to become established under the local environmental conditions (hence, a reclamation strategy is recommended) and (ii) biotechnological manipulation of the seedlings to be used for revegetation (by inoculation with selected rhizobia and mycorrhizal fungi) improved outplanting performance, plant survival, and biomass development. PMID:16348838

  1. The fate and efficacy of benomyl applied to field soils to suppress activity of arbuscular mycorrhizal fungi.

    PubMed

    O'Connor, Patrick; Manjarrez, Maria; Smith, Sally E

    2009-07-01

    A systematic application of the fungicide benomyl was used to follow up the suppression of arbuscular mycorrhizal (AM) colonization and to determine its fungitoxic activity and persistence at different depths. Repeated applications of benomyl reduced AM colonization mainly in the upper 0-4 cm layer of the treated soils. Furthermore, AM colonization decreased with soil depth. The activity and persistence of this fungicide was reduced over small changes in depth in the first 10 cm of the soil profile beneath a semiarid herbland at Brookfield Conservation Park (South Australia). Repeated applications of the fungicide only slightly increased the levels of toxicity in the soils, probably because of biodegradation of the fungicide in soils with a recent history of exposure to the fungicide. The decline in fungicide activity at depth was correlated with a decline in the suppressive effect of the fungicide on the activity of AM fungi.

  2. Arbuscular mycorrhizal fungi in phytoremediation of contaminated areas by trace elements: mechanisms and major benefits of their applications.

    PubMed

    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. PMID:26250548

  3. Arbuscular mycorrhizal fungi in phytoremediation of contaminated areas by trace elements: mechanisms and major benefits of their applications.

    PubMed

    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.

  4. Arbuscular mycorrhizal fungi in a wetland constructed for benzene-, methyl tert-butyl ether- and ammonia-contaminated groundwater bioremediation

    PubMed Central

    Fester, Thomas

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF), which are present in most natural environments, have demonstrated capacity to promote biodegradation of organic pollutants in the greenhouse. However, it is not certain whether AMF can spontaneously establish in phytoremediation systems constructed to decontaminate groundwater, because of the unusual conditions during the construction and operation of such systems. To assess this possibility, root samples from a wetland constructed for the phytoremediation of groundwater contaminated with benzene, methyl tert-butyl ether and ammonia were analysed. Substantial AMF colonization was observed in plant roots sampled close to the inlet of a basin filled with fine gravel and planted with Phragmites australis. In addition, analysis of a fragment of the nuclear large ribosomal subunit, amplified by nested PCR, revealed the presence of AMF molecular operational taxonomic units closely related to Funneliformis mosseae and Rhizophagus irregularis in the samples. These findings demonstrate the capacity of generalist AMF strains to establish spontaneously, rapidly and extensively in groundwater bioremediation technical installations. PMID:22846140

  5. Synergistic effects of Arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria in bioremediation of iron contaminated soils.

    PubMed

    Mishra, Vartika; Gupta, Antriksh; Kaur, Parvinder; Singh, Simranjeet; Singh, Nasib; Gehlot, Praveen; Singh, Joginder

    2016-01-01

    Three Arbuscular mycorrhizal fungi (AMF) from Glomus, Acaulospora and Scutellospora, and four plant growth promoting rhizobacteria (PGPR) isolates related to genera Streptomyces, Azotobacter, Pseudomonas and Paenibacillus were found to be effective in phytoremediation of Fe(3+) contaminated soil where Pennisetum glaucum and Sorghum bicolor were growing as host plants. Co-inoculation of AMF and PGPR showed better results in comparison to either, AMF and PGPR under pot conditions. Both AMF and PGPR were able to produce siderophores. AMF and PGPR associated to P. glaucum and S. bicolor plants increased the extent of iron absorption. AMF and PGPR combination exhibited superior (p < 0.01) phytoremediation efficiency with P. glaucum compared to S. bicolor. These findings warrant further investigations of these synergistic interactions and large-scale in situ studies for bioremediation of iron-contaminated soils. PMID:26682583

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

    PubMed

    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.].

  7. Gibberellin regulates infection and colonization of host roots by arbuscular mycorrhizal fungi

    PubMed Central

    Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

    2015-01-01

    Arbuscular mycorrhiza (AM) is established by the entry of AM fungi into the host plant roots and the formation of symbiotic structures called arbuscules. The host plant supplies photosynthetic products to the AM fungi, which in return provide phosphate and other minerals to the host through the arbuscules. Both partners gain great advantages from this symbiotic interaction, and both regulate AM development. Our recent work revealed that gibberellic acids (GAs) are required for AM development in the legume Lotus japonicus. GA signaling interact with symbiosis signaling pathways, directing AM fungal colonization in host roots. Expression analysis showed that genes for GA biosynthesis and metabolism were induced in host roots around AM fungal hyphae, suggesting that the GA signaling changes with both location and time during AM development. The fluctuating GA concentrations sometimes positively and sometimes negatively affect the expression of AM-induced genes that regulate AM fungal infection and colonization. PMID:26024424

  8. Molecular diversity of arbuscular mycorrhizal fungi in onion roots from organic and conventional farming systems in the Netherlands.

    PubMed

    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.

  9. Diversity of arbuscular mycorrhizal fungi in soil from the Pampa Ondulada, Argentina, assessed by pyrosequencing and morphological techniques.

    PubMed

    Colombo, R P; Fernández Bidondo, L; Silvani, V A; Carbonetto, M B; Rascovan, N; Bompadre, M J; Pérgola, M; Cuenca, G; Godeas, A M

    2014-12-01

    The aim of this study was to assess the effects of agronomic practices on the arbuscular mycorrhizal (AM) fungal community in soils from the Pampa Ondulada region (Argentina), and to compare conclusions reached when using pyrosequencing or a morphological approach. The AM fungal diversity of 3 agricultural exploitations located in the Pampa Ondulada region (Argentina) was assessed by using 454 amplicon pyrosequencing and morphological (based on spore traits) approaches. Two kinds of soil managements are found in these sites: agronomic and non-agronomic. A total of 188 molecular operational taxonomic units and 29 morphological species of AM fungi were identified. No effect of soil management on AM richness was detected. AM fungal communities were more diverse and equitable in the absence of agronomic management. In contrast, the results on β-diversity varied according to the methodology used. We concluded that agronomic management of soil has a negative effect on AM fungal community biodiversity in the Pampa Ondulada region. We also conclude that both methodologies complement each other in the study of AM fungal ecology. This study greatly improved the knowledge about AM fungi in South America where the molecular diversity of AM fungi was practically unknown.

  10. Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

    SciTech Connect

    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.

  11. Land-use intensity and host plant identity interactively shape communities of arbuscular mycorrhizal fungi in roots of grassland plants.

    PubMed

    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.

  12. Molecular evolution patterns reveal life history features of mycoplasma-related endobacteria associated with arbuscular mycorrhizal fungi.

    PubMed

    Toomer, Kevin H; Chen, Xiuhua; Naito, Mizue; Mondo, Stephen J; den Bakker, Henk C; VanKuren, Nicholas W; Lekberg, Ylva; Morton, Joseph B; Pawlowska, Teresa E

    2015-07-01

    The mycoplasma-related endobacteria (MRE), representing a recently discovered lineage of Mollicutes, are widely distributed across arbuscular mycorrhizal fungi (AMF, Glomeromycota). AMF colonize roots of most terrestrial plants and improve plant mineral nutrient uptake in return for plant-assimilated carbon. The role of MRE in the biology of their fungal hosts is unknown. To start characterizing this association, we assessed partitioning of MRE genetic diversity within AMF individuals and across the AMF phylogeographic range. We further used molecular evolution patterns to make inferences about MRE codivergence with AMF, their lifestyle and antiquity of the Glomeromycota-MRE association. While we did not detect differentiation between MRE derived from different continents, high levels of diversity were apparent in MRE populations within AMF host individuals. MRE exhibited significant codiversification with AMF over ecological time and the absence of codivergence over evolutionary time. Moreover, genetic recombination was evident in MRE. These patterns indicate that, while MRE transmission is predominantly vertical, their complex intrahost populations are likely generated by horizontal transmission and recombination. Based on predictions of evolutionary theory, we interpreted these observations as a suggestion that MRE may be antagonists of AMF. Finally, we detected a marginally significant signature of codivergence of MRE with Glomeromycota and the Endogone lineage of Mucoromycotina, implying that the symbiosis between MRE and fungi may predate the divergence between these two groups of fungi.

  13. Influence of soil organic matter decomposition on arbuscular mycorrhizal fungi in terms of asymbiotic hyphal growth and root colonization.

    PubMed

    Gryndler, Milan; Hrselová, Hana; Cajthaml, Tomás; Havránková, Marie; Rezácová, Veronika; Gryndlerová, Hana; Larsen, John

    2009-04-01

    Soil organic matter is known to influence arbuscular mycorrhizal (AM) fungi, but limited information is available on the chemical components in the organic matter causing these effects. We studied the influence of decomposing organic matter (pure cellulose and alfalfa shoot and root material) on AM fungi after 30, 100, and 300 days of decomposition in nonsterile soil with and without addition of mineral N and P. Decomposing organic matter affected maize root length colonized by the AM fungus Glomus claroideum in a similar manner as other plant growth parameters. Colonized root length was slightly increased by both nitrogen and phosphorus application and plant materials, but not by application of cellulose. In vitro hyphal growth of Glomus intraradices was increased by soil extracts from the treatments with all types of organic materials independently of mineral N and P application. Pyrolysis of soil samples from the different decomposition treatments revealed in total 266 recognizable organic compounds and in vitro hyphal growth of G. intraradices in soil extract positively correlated with 33 of these compounds. The strongest correlation was found with 3,4,5-trimethoxybenzoic acid methyl ester. This compound is a typical product of pyrolysis of phenolic compounds produced by angiosperm woody plants, but in our experiment, it was produced mainly from cellulose by some components of the soil microflora. In conclusion, our results indicate that mycelia of AM fungi are influenced by organic matter decomposition both via compounds released during the decomposition process and also by secondary metabolites produced by microorganisms involved in organic matter decomposition.

  14. Improvement of the soil nitrogen content and maize growth by earthworms and arbuscular mycorrhizal fungi in soils polluted by oxytetracycline.

    PubMed

    Cao, Jia; Wang, Chong; Ji, Dingge

    2016-11-15

    Interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungi (Rhizophagus intraradices, AM fungi) have been suggested to improve the maize nitrogen (N) content and biomass and were studied in soils polluted by oxytetracycline (OTC). Maize was planted and amended with AMF and/or earthworms (E) in the soil with low (1mgkg(-1) soil DM) or high (100mgkg(-1) soil DM) amounts of OTC pollution in comparison to soil without OTC. The root colonization, shoot and root biomass, shoot and root N contents, soil nitrogen forms, ammonia-oxidizing bacteria (AOB) and archaea (AOA) were measured at harvest. The results indicated that OTC decreased maize shoot and root biomass (p<0.05) by mediating the soil urease activity and AOB and AOA abundance, which resulted in a lower N availability for maize roots and shoots. There was a significant interaction between earthworms and AM fungi on the urease activity in soil polluted by OTC (p<0.05). Adding earthworms or AM fungi could increase the maize biomass and N content (p<0.05) in OTC polluted soil by increasing the urease activity and relieving the stress from OTC on the soil N cycle. AM fungi and earthworms interactively increased maize shoot and root biomass (p<0.05) in the OTC polluted soils through their regulation of the urease activity and the abundance of ammonia oxidizers, resulting in different soil NH4(+)-N and NO3(-)-N contents, which may contribute to the N content of maize shoots and roots. Earthworms and AM fungi could be used as an efficient method to relieve the OTC stress in agro-ecosystems. PMID:27496075

  15. Improvement of the soil nitrogen content and maize growth by earthworms and arbuscular mycorrhizal fungi in soils polluted by oxytetracycline.

    PubMed

    Cao, Jia; Wang, Chong; Ji, Dingge

    2016-11-15

    Interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungi (Rhizophagus intraradices, AM fungi) have been suggested to improve the maize nitrogen (N) content and biomass and were studied in soils polluted by oxytetracycline (OTC). Maize was planted and amended with AMF and/or earthworms (E) in the soil with low (1mgkg(-1) soil DM) or high (100mgkg(-1) soil DM) amounts of OTC pollution in comparison to soil without OTC. The root colonization, shoot and root biomass, shoot and root N contents, soil nitrogen forms, ammonia-oxidizing bacteria (AOB) and archaea (AOA) were measured at harvest. The results indicated that OTC decreased maize shoot and root biomass (p<0.05) by mediating the soil urease activity and AOB and AOA abundance, which resulted in a lower N availability for maize roots and shoots. There was a significant interaction between earthworms and AM fungi on the urease activity in soil polluted by OTC (p<0.05). Adding earthworms or AM fungi could increase the maize biomass and N content (p<0.05) in OTC polluted soil by increasing the urease activity and relieving the stress from OTC on the soil N cycle. AM fungi and earthworms interactively increased maize shoot and root biomass (p<0.05) in the OTC polluted soils through their regulation of the urease activity and the abundance of ammonia oxidizers, resulting in different soil NH4(+)-N and NO3(-)-N contents, which may contribute to the N content of maize shoots and roots. Earthworms and AM fungi could be used as an efficient method to relieve the OTC stress in agro-ecosystems.

  16. Vegetative compatibility and anastomosis formation within and among individual germlings of tropical isolates of arbuscular mycorrhizal fungi (Glomeromycota).

    PubMed

    de Novais, Cândido Barreto; Sbrana, Cristiana; Saggin Júnior, Orivaldo José; Siqueira, José Oswaldo; Giovannetti, Manuela

    2013-05-01

    Hyphal anastomoses which play a key role in the formation of interconnected mycorrhizal networks and in genetic exchange among compatible individuals have been studied in a limited number of species and isolates of arbuscular mycorrhizal fungi (AMF), mainly in symbiotic mycelium. In this work, the occurrence and frequency of anastomosis between hyphae of the same and different germlings were assessed in tropical isolates belonging to Acaulospora, Claroideoglomus, Gigaspora, Glomus, Rhizophagus and Scutellospora. Germlings belonging to Acaulospora, Claroideoglomus, Glomus and Rhizophagus formed perfect hyphal fusions, with frequencies ranging from 9.29 ± 3.01 to 79.84 ± 4.39 % within the same germling and from 14.02 ± 7.36 to 91.41 ± 3.92 % between different germlings. Rare fusions, occurring within the same hypha, were detected in Gigaspora species, and no anastomoses were observed in Scutellospora species. The consistent detection of nuclei in perfect fusions suggests that nuclear migration is active both within and between germlings. Present data on anastomosis formation, nuclear migration and germling viability in tropical isolates of AMF widen our knowledge on the extensive and consistent occurrence of successful hyphal fusions in this group of beneficial symbionts. The ability to anastomose and establish protoplasm flow, fundamental for the maintenance of physiological and genetic continuity, may produce important fitness consequences for the obligately biotrophic AMF.

  17. Native arbuscular mycorrhizal fungi isolated from a saline habitat improved maize antioxidant systems and plant tolerance to salinity.

    PubMed

    Estrada, Beatriz; Aroca, Ricardo; Barea, José Miguel; Ruiz-Lozano, Juan Manuel

    2013-03-01

    High soil salinity is a serious problem for crop production because most of the cultivated plants are salt sensitive, which is also the case for the globally important crop plant maize. Salinity stress leads to secondary oxidative stress in plants and a correlation between antioxidant capacity and salt tolerance has been demonstrated in several plant species. The plant antioxidant capacity may be enhanced by arbuscular mycorrhizal fungi (AMF) and it has been proposed that AM symbiosis is more effective with native than with collection AMF species. Thus, we investigated whether native AMF isolated from a dry and saline environment can help maize plants to overcome salt stress better than AMF from a culture collection and whether protection against oxidative stress is involved in such an effect. Maize plants inoculated with three native AMF showed higher efficiency of photosystem II and stomatal conductance, which surely decreased photorespiration and ROS production. Indeed, the accumulation of hydrogen peroxide, the oxidative damage to lipids and the membrane electrolyte leakage in these AM plants were significantly lower than in non-mycorrhizal plants or in plants inoculated with the collection AMF. The activation of antioxidant enzymes such as superoxide dismutase or catalase also accounted for these effects.

  18. Short-term consequences of slash-and-burn practices on the arbuscular mycorrhizal fungi of a tropical dry forest.

    PubMed

    Aguilar-Fernández, Mónica; Jaramillo, Víctor J; Varela-Fregoso, Lucía; Gavito, Mayra E

    2009-03-01

    Rates of land conversion from forest to cultivated land by slash-and-burn practices are higher in tropical dry forest (TDF) than any other Neotropical forest type. This study examined the short-term consequences of the slash-and-burn process on arbuscular mycorrhizal fungi (AMF). We expected that slash-and-burn would reduce mycorrhizal colonization and propagules and change species richness and composition. Soil and root samples were taken from TDF control and pasture plots originated after slash-and-burn at four dates during the year of conversion to examine species composition, spore abundance, and infective propagules. Additionally, spore abundance and viability and viable intraradical colonization were measured twice during the second year after conversion. Forest and pasture plots maintained similar species richness and an overall 84% similarity during the first year after conversion. Infective propagules were reduced in pasture plots during the first year after slash-and-burn, whereas spore abundance and intraradical colonization remained similar in TDF and pasture plots both years of the study. Our results suggest, contrary to the expected, that forest conversion by means of slash-and-burn followed by cultivation resulted in few immediate changes in the AMF communities, likely because of the low heat conductivity of the soil and rapid combustion of plant residues. PMID:19169717

  19. Current developments in arbuscular mycorrhizal fungi research and its role in salinity stress alleviation: a biotechnological perspective.

    PubMed

    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. PMID:24708070

  20. Bacterial degradation of Aroclor 1242 in the mycorrhizosphere soils of zucchini (Cucurbita pepo L.) inoculated with arbuscular mycorrhizal fungi.

    PubMed

    Qin, Hua; Brookes, Philip C; Xu, Jianming; Feng, Youzhi

    2014-11-01

    A greenhouse experiment was conducted to investigate the effects of zucchini (Cucurbita pepo L.), inoculated with the arbuscular mycorrhizal (AM) species Acaulospora laevis, Glomus caledonium, and Glomus mosseae, on the soil bacterial community responsible for Aroclor 1242 dissipation. The dissipation rates of Aroclor 1242 and soil bacteria abundance were much higher with the A. laevis and G. mosseae treatments compared to the non-mycorrhizal control. The biphenyl dioxygenase (bphA) and Rhodococcus-like 2,3-dihydroxybiphenyl dioxygenase (bphC) genes were more abundant in AM inoculated soils, suggesting that the bphA and Rhodococcus-like bphC pathways play an important role in Aroclor 1242 dissipation in the mycorrhizosphere. The soil bacterial communities were dominated by classes Betaproteobacteria and Actinobacteria, while the relative proportion of Actinobacteria was significantly (F=2.288, P<0.05) correlated with the PCB congener profile in bulk soil. Our results showed that AM fungi could enhance PCB dissipation by stimulating bph gene abundance and the growth of specific bacterial groups.

  1. Evaluation of arbuscular mycorrhizal fungi capacity to alleviate abiotic stress of olive (Olea europaea L.) plants at different transplant conditions.

    PubMed

    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.

  2. Evaluation of Arbuscular Mycorrhizal Fungi Capacity to Alleviate Abiotic Stress of Olive (Olea europaea L.) Plants at Different Transplant Conditions

    PubMed Central

    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

  3. Evaluation of arbuscular mycorrhizal fungi capacity to alleviate abiotic stress of olive (Olea europaea L.) plants at different transplant conditions.

    PubMed

    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

  4. Contribution of arbuscular mycorrhizal fungi of sedges to soil aggregation along an altitudinal alpine grassland gradient on the Tibetan Plateau.

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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. PMID:20943558

  8. Fungal spore diversity of arbuscular mycorrhizal fungi associated with spring wheat: effects of tillage.

    PubMed

    Schalamuk, S; Velazquez, S; Chidichimo, H; Cabello, M

    2006-01-01

    We investigated the influence of tilling, N fertilization and crop stage on arbuscular mycorrhizae (AM) fungal species diversity in a wheat monoculture in the Pampa region of Argentina. Glomalean spores were isolated by wet sieving and decanting from conventionally tilled and nontilled soils cropped with wheat with or without N fertilization, at three phenological stages of the crop (tilling, flowering and grain filling) and fallow. Morphological characterization yielded at least 24 AM fungi taxa in the field samples, belonging to six genera of AMF: Acaulospora Archaeospora, Entrophospora, Gigaspora, Glomus and Scutellospora. Tilling and fertilization treatments did not result in decreased spore biodiversity. Wheat phenology influenced AM communities, with highest spore biodiversity during grain filling.

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

    PubMed

    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. PMID:27072359

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

    PubMed

    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.

  11. Arbuscular mycorrhizal fungi associated with Populus-Salix stands in a semiarid riparian ecosystem

    USGS Publications Warehouse

    Beauchamp, Vanessa B.; Stromberg, J.C.; Stutz, J.C.

    2006-01-01

    ??? This study examined the activity, species richness, and species composition of the arbuscular mycorrhizal fungal (AMF) community of Populus-Salix stands on the Verde River (Arizona, USA), quantified patterns of AMF richness and colonization along complex floodplain gradients, and identified environmental variables responsible for structuring the AMF community. ??? Samples from 61 Populus-Salix stands were analyzed for AMF and herbaceous composition, AMF colonization, gravimetric soil moisture, soil texture, per cent organic matter, pH, and concentrations of nitrate, bicarbonate phosphorus and exchangeable potassium. ??? AMF species richness declined with stand age and distance from and elevation above the channel and was positively related to perennial species cover and richness and gravimetric soil moisture. Distance from and elevation above the active channel, forest age, annual species cover, perennial species richness, and exchangeable potassium concentration all played a role in structuring the AMF community in this riparian area. ??? Most AMF species were found across a wide range of soil conditions, but a subset of species tended to occur more often in hydric areas. This group of riparian affiliate AMF species includes several not previously encountered in the surrounding Sonoran desert. ?? New Phytologist (2006).

  12. Development of Soils and Communities of Plants and Arbuscular Mycorrhizal Fungi on West Virginia Surface Mines

    NASA Astrophysics Data System (ADS)

    Levy, Michael A.; Cumming, Jonathan R.

    2014-11-01

    Surface mining followed by reclamation to pasture is a major driver of land use and cover change in Appalachia. Prior research suggests that many aspects of ecosystem recovery are either slow or incomplete. We examined ecosystem structure—including soil physical and chemical properties, arbuscular mycorrhizal fungal (AMF) infectivity and community composition, and plant diversity and community composition—on a chronosequence of pasture-reclaimed surface mines and a non-mined pasture in northern West Virginia. Surface mining and reclamation dramatically altered ecosystem structure. Some aspects of ecosystem structure, including many measures of soil chemistry and infectivity of AMF, returned rapidly to levels found on the non-mined reference site. Other aspects of ecosystem structure, notably soil physical properties and AMF and plant communities, showed incomplete or no recovery over the short-to-medium term. In addition, invasive plants were prevalent on reclaimed mine sites. The results point to the need for investigation on how reclamation practices could minimize establishment of exotic invasive plant species and reduce the long-term impacts of mining on ecosystem structure and function.

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

    PubMed

    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.

  14. [Combined remediation effects of arbuscular mycorrhizal fungi-legumes-rhizobium symbiosis on PCBs contaminated soils].

    PubMed

    Teng, Ying; Luo, Yong-Ming; Gao, Jun; Li, Zhen-Gao

    2008-10-01

    The combined remediation effects of dual inoculation with an arbuscular mycorrhizal fungus (AM) and rhizabium (Rhizobium meliloti) with a host plant (alfalfa) on PCBs contaminated soils was studied using pot experiments. The results showed that alfalfa had a clear role in PCBs removal in soils compared with treatments without alfalfa and inoculated microorganisms, PCBs concentration in lightly and heavily polluted soils decreased 15.8% and 23.5%, respectively. After planting alfalfa with single incubation of Glomus caledonium, PCBs concentration decreased 14.8% and 24.1% from lightly and heavily polluted soils, decreased 20.6% and 25.5% for single incubation of Rhizobium meliloti, respectively. After dual incubation with Glomus caledonium and Rhizobium meliloi, PCBs concentration in lightly and heavily polluted soils decreased 23.2% and 26.9%. We also observed that soil microbial communities in alfalfa rhizosphere soils had a higher carbon utilization rate, improving the functional diversity of the soil microbial community. The results suggest that dual incubation of Glomus caledonium and Rhizobium meliloti has great potential in remediation of PCBs contaminated soils.

  15. Development of soils and communities of plants and arbuscular mycorrhizal fungi on West Virginia surface mines.

    PubMed

    Levy, Michael A; Cumming, Jonathan R

    2014-11-01

    Surface mining followed by reclamation to pasture is a major driver of land use and cover change in Appalachia. Prior research suggests that many aspects of ecosystem recovery are either slow or incomplete. We examined ecosystem structure-including soil physical and chemical properties, arbuscular mycorrhizal fungal (AMF) infectivity and community composition, and plant diversity and community composition-on a chronosequence of pasture-reclaimed surface mines and a non-mined pasture in northern West Virginia. Surface mining and reclamation dramatically altered ecosystem structure. Some aspects of ecosystem structure, including many measures of soil chemistry and infectivity of AMF, returned rapidly to levels found on the non-mined reference site. Other aspects of ecosystem structure, notably soil physical properties and AMF and plant communities, showed incomplete or no recovery over the short-to-medium term. In addition, invasive plants were prevalent on reclaimed mine sites. The results point to the need for investigation on how reclamation practices could minimize establishment of exotic invasive plant species and reduce the long-term impacts of mining on ecosystem structure and function.

  16. Interaction of Vesicular-Arbuscular Mycorrhizal Fungi with Erosion in an Oxisol †

    PubMed Central

    Habte, M.; Fox, R. L.; Aziz, T.; El-Swaify, S. A.

    1988-01-01

    The development of vesicular-arbuscular mycorrhizal (VAM) symbiosis was monitored in Leucaena leucocephala grown in an Oxisol subjected to incremental simulated erosion. The density of VAM infective propagules in the soil diminished as the level of simulated erosion (removal of surface soil) was increased from 0 to 50 cm. The level of infection on L. leucocephala roots observed at harvest was not significantly influenced by simulated erosion unless removal of surface soil exceeded 25 cm. Inoculation of this soil and the uneroded soil with Glomus aggregatum enhanced the early onset of infection but did not significantly influence the level of infection observed at the time of harvest. Simulated erosion in excess of 7.5 cm of surface soil removal significantly delayed the development of VAM effectiveness monitored in terms of the P status of L. leucocephala subleaflets and also curtailed the level of maximum effectiveness observed. Decreases in VAM effectiveness were significantly correlated with decreases in soil chemical constituents. However, VAM effectiveness in a soil subjected to 30 cm of surface soil removal was not restored to a significant extent unless the soil was amended with P, even though other nutrients were restored to sufficiency levels. Our results demonstrate that the development of VAM effectiveness is the phase of the VAM symbiosis that is most adversely influenced by simulated erosion and that this effect appears to be caused primarily by insufficient P in the soil solution. PMID:16347615

  17. Development of soils and communities of plants and arbuscular mycorrhizal fungi on West Virginia surface mines.

    PubMed

    Levy, Michael A; Cumming, Jonathan R

    2014-11-01

    Surface mining followed by reclamation to pasture is a major driver of land use and cover change in Appalachia. Prior research suggests that many aspects of ecosystem recovery are either slow or incomplete. We examined ecosystem structure-including soil physical and chemical properties, arbuscular mycorrhizal fungal (AMF) infectivity and community composition, and plant diversity and community composition-on a chronosequence of pasture-reclaimed surface mines and a non-mined pasture in northern West Virginia. Surface mining and reclamation dramatically altered ecosystem structure. Some aspects of ecosystem structure, including many measures of soil chemistry and infectivity of AMF, returned rapidly to levels found on the non-mined reference site. Other aspects of ecosystem structure, notably soil physical properties and AMF and plant communities, showed incomplete or no recovery over the short-to-medium term. In addition, invasive plants were prevalent on reclaimed mine sites. The results point to the need for investigation on how reclamation practices could minimize establishment of exotic invasive plant species and reduce the long-term impacts of mining on ecosystem structure and function. PMID:25195033

  18. Interaction of vesicular-arbuscular mycorrhizal fungi with erosion in an oxisol.

    PubMed

    Habte, M; Fox, R L; Aziz, T; El-Swaify, S A

    1988-04-01

    The development of vesicular-arbuscular mycorrhizal (VAM) symbiosis was monitored in Leucaena leucocephala grown in an Oxisol subjected to incremental simulated erosion. The density of VAM infective propagules in the soil diminished as the level of simulated erosion (removal of surface soil) was increased from 0 to 50 cm. The level of infection on L. leucocephala roots observed at harvest was not significantly influenced by simulated erosion unless removal of surface soil exceeded 25 cm. Inoculation of this soil and the uneroded soil with Glomus aggregatum enhanced the early onset of infection but did not significantly influence the level of infection observed at the time of harvest. Simulated erosion in excess of 7.5 cm of surface soil removal significantly delayed the development of VAM effectiveness monitored in terms of the P status of L. leucocephala subleaflets and also curtailed the level of maximum effectiveness observed. Decreases in VAM effectiveness were significantly correlated with decreases in soil chemical constituents. However, VAM effectiveness in a soil subjected to 30 cm of surface soil removal was not restored to a significant extent unless the soil was amended with P, even though other nutrients were restored to sufficiency levels. Our results demonstrate that the development of VAM effectiveness is the phase of the VAM symbiosis that is most adversely influenced by simulated erosion and that this effect appears to be caused primarily by insufficient P in the soil solution. PMID:16347615

  19. Increased photosynthetic acclimation in alfalfa associated with arbuscular mycorrhizal fungi (AMF) and cultivated in greenhouse under elevated CO2.

    PubMed

    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. PMID:25240322

  20. Increased photosynthetic acclimation in alfalfa associated with arbuscular mycorrhizal fungi (AMF) and cultivated in greenhouse under elevated CO2.

    PubMed

    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.

  1. Arbuscular mycorrhizal fungi in soil and roots respond differently to phosphorus inputs in an intensively managed calcareous agricultural soil.

    PubMed

    Liu, Wei; Zhang, Yunlong; Jiang, Shanshan; Deng, Yan; Christie, Peter; Murray, Philip J; Li, Xiaolin; Zhang, Junling

    2016-01-01

    Understanding the diversity and community structure of arbuscular mycorrhizal fungi (AMF) is important for potentially optimizing their role in mining phosphorus (P) in agricultural ecosystems. Here, we conduct a comprehensive study to investigate the vertical distribution of AMF in a calcareous field and their temporal structure in maize-roots with fertilizer P application over a three-year period. The results showed that soil available-P response to P fertilization but maize yields did not. Phosphorus fertilization had no-significant effect on richness of AMF except at greater soil-depths. High P-supply reduced root colonization while optimum-P tended to increase colonization and fungal richness on all sampling occasions. Crop phenology might override P-supply in determining the community composition of active root inhabiting fungi. Significant differences in the community structure of soil AMF were observed between the controls and P treatments in surface soil and the community shift was attributable mainly to available-P, N/P and pH. Vertical distribution was related mainly to soil electrical conductivity and Na content. Our results indicate that the structure of AMF community assemblages is correlated with P fertilization, soil depth and crop phenology. Importantly, phosphorus management must be integrated with other agricultural-practices to ensure the sustainability of agricultural production in salinized soils. PMID:27102357

  2. Arbuscular mycorrhizal fungi in soil and roots respond differently to phosphorus inputs in an intensively managed calcareous agricultural soil

    PubMed Central

    Liu, Wei; Zhang, Yunlong; Jiang, Shanshan; Deng, Yan; Christie, Peter; Murray, Philip J.; Li, Xiaolin; Zhang, Junling

    2016-01-01

    Understanding the diversity and community structure of arbuscular mycorrhizal fungi (AMF) is important for potentially optimizing their role in mining phosphorus (P) in agricultural ecosystems. Here, we conduct a comprehensive study to investigate the vertical distribution of AMF in a calcareous field and their temporal structure in maize-roots with fertilizer P application over a three-year period. The results showed that soil available-P response to P fertilization but maize yields did not. Phosphorus fertilization had no-significant effect on richness of AMF except at greater soil-depths. High P-supply reduced root colonization while optimum-P tended to increase colonization and fungal richness on all sampling occasions. Crop phenology might override P-supply in determining the community composition of active root inhabiting fungi. Significant differences in the community structure of soil AMF were observed between the controls and P treatments in surface soil and the community shift was attributable mainly to available-P, N/P and pH. Vertical distribution was related mainly to soil electrical conductivity and Na content. Our results indicate that the structure of AMF community assemblages is correlated with P fertilization, soil depth and crop phenology. Importantly, phosphorus management must be integrated with other agricultural-practices to ensure the sustainability of agricultural production in salinized soils. PMID:27102357

  3. Cropping practices modulate the impact of glyphosate on arbuscular mycorrhizal fungi and rhizosphere bacteria in agroecosystems of the semiarid prairie.

    PubMed

    Sheng, Min; Hamel, Chantal; Fernandez, Myriam R

    2012-08-01

    A growing body of evidence obtained from studies performed under controlled conditions suggests that glyphosate use can modify microbial community assemblages. However, few studies have examined the influence of glyphosate in agroecosystems. We examined 4 wheat-based production systems typical of the Canadian prairie over 2 years to answer the following question: Does preseeding of glyphosate impact soil rhizosphere microorganisms? If so, do cropping practices influence this impact? Glyphosate caused a shift in the species dominating the arbuscular mycorrhizal fungal community in the rhizosphere, possibly through the modification of host plant physiology. Glyphosate stimulated rhizobacterial growth while having no influence on saprotrophic fungi, suggesting a greater abundance of glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in bacteria than in fungi. Glyphosate stimulated rhizosphere bacteria in pea but not in urea-fertilized durum wheat, which is consistent with inhibition of EPSPS tolerance to residual glyphosate through high ammonium levels. Mitigation of the effects of glyphosate on rhizosphere bacteria through tillage suggests a reduction in residual glyphosate activity through increased adsorption to soil binding sites upon soil mixing. The influence of glyphosate on Gram-negative bacteria was mitigated under drought conditions in 2007. Our experiment suggests that interactions between soil fertility, tillage, and cropping practices shape the influence of glyphosate use on rhizosphere microorganisms.

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

    PubMed

    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. Diversity of Arbuscular Mycorrhizal Fungi in the Growth Habitat of Kayu Kuku (Pericopsis mooniana Thw.) In Southeast Sulawesi.

    PubMed

    Husna; Budi, Sri Wilarso; Mansur, Irdika; Kusmana, Dan Cecep

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) are categorized as fungi which have symbioses with terrestrial plants and are distributed in various habitat types. The objectives of this research were to investigate the diversity of AMF in stands of kayu kuku (Pericopsis mooniana Thw.) in Southeast Sulawesi. Collection of samples of soil and root were conducted in six locations. Isolation of spores used the method of wet sieving and decanting, whereas AMF identification was conducted by observing morphology of AMF spores. Parameters of AMF diversity, namely species richness, diversity index, dominance index, evenness index and colonization were studied using method of infected root length. Research results showed that location differences affected significantly the spore density and parameters of AMF diversity, except colonization of AMF (p < 0.116). Location around the Governor office showed the highest number of spores (208.6 spores/100 g of soil). Soil chemical properties, such as C, N, P and heavy metal contributed towards AMF spore density and diversity. Soil C and N correlated negatively with spore density. In terms of location, Glomeraceae constituted the genera with the largest number of species and possessed wide distribution in all research locations. In general, natural forest has higher AMF diversity index (Shannon-Weiner diversity index-H'), evenness (E) and species richness (S) as compared with location of PT. Vale Indonesia Tbk. PMID:26353410

  6. Arbuscular mycorrhizal fungi in national parks, nature reserves and protected areas worldwide: a strategic perspective for their in situ conservation.

    PubMed

    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.

  7. Diversity of Arbuscular Mycorrhizal Fungi in the Growth Habitat of Kayu Kuku (Pericopsis mooniana Thw.) In Southeast Sulawesi.

    PubMed

    Husna; Budi, Sri Wilarso; Mansur, Irdika; Kusmana, Dan Cecep

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) are categorized as fungi which have symbioses with terrestrial plants and are distributed in various habitat types. The objectives of this research were to investigate the diversity of AMF in stands of kayu kuku (Pericopsis mooniana Thw.) in Southeast Sulawesi. Collection of samples of soil and root were conducted in six locations. Isolation of spores used the method of wet sieving and decanting, whereas AMF identification was conducted by observing morphology of AMF spores. Parameters of AMF diversity, namely species richness, diversity index, dominance index, evenness index and colonization were studied using method of infected root length. Research results showed that location differences affected significantly the spore density and parameters of AMF diversity, except colonization of AMF (p < 0.116). Location around the Governor office showed the highest number of spores (208.6 spores/100 g of soil). Soil chemical properties, such as C, N, P and heavy metal contributed towards AMF spore density and diversity. Soil C and N correlated negatively with spore density. In terms of location, Glomeraceae constituted the genera with the largest number of species and possessed wide distribution in all research locations. In general, natural forest has higher AMF diversity index (Shannon-Weiner diversity index-H'), evenness (E) and species richness (S) as compared with location of PT. Vale Indonesia Tbk.

  8. Arbuscular mycorrhizal fungi in national parks, nature reserves and protected areas worldwide: a strategic perspective for their in situ conservation.

    PubMed

    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. PMID:22075570

  9. On-farm production of inoculum of indigenous arbuscular mycorrhizal fungi and assessment of diluents of compost for inoculum production.

    PubMed

    Douds, David D; Nagahashi, Gerald; Hepperly, Paul Reed

    2010-04-01

    On-farm production of arbuscular mycorrhizal [AM] fungus inoculum can be employed to make the benefits of the symbiosis more available to vegetable farmers. Experiments were conducted to modify an existing method for the production of inoculum in temperate climates to make it more readily adoptable by farmers. Perlite, vermiculite, and peat based potting media were tested as diluents of yard clippings compost for the media in which the inoculum was produced using bahiagrass (Paspalum notatum Flugge) as host plant. All produced satisfactory concentrations of AM fungus propagules, though vermiculite proved to be better than potting media (89 vs. 25 propagules cm(-3), respectively). Two methods were tested for the growth of AM fungi indigenous to the farm: (1) adding field soil into the vermiculite and compost mixture and (2) pre-colonizing the bahiagrass seedlings in media inoculated with field soil prior to transplant into that mixture. Adding 100 cm(3) of field soil to the compost and vermiculite produced 465 compared to 137 propagules cm(-3) for the pre-colonization method. The greater flexibility these modifications give will make it easier for farmers to produce inoculum of AM fungi on-the-farm.

  10. Distribution and diversity of arbuscular mycorrhizal fungi in grapevines from production vineyards along the eastern Adriatic coast.

    PubMed

    Likar, Matevž; Hančević, Katarina; Radić, Tomislav; Regvar, Marjana

    2013-04-01

    The colonisation and diversity of arbuscular mycorrhizal fungi (AMF) on roots of grapevines were investigated in production vineyards located along a 500-km-long stretch of karst along the coast of the Adriatic Sea. AMF communities on roots of grapevines were analysed using temporal temperature gel electrophoresis and sequencing of the 18S and internal transcribed spacer segments of the rDNA operon. The AMF colonisation of these grapevines roots was consistent along the whole of this east Adriatic karst region, at 64 to 82% of fine roots. The comparison of the AMF communities on the roots of these grapevines showed that the fungal community associated with grapevine roots seems to be relatively stable, with inter-vineyard variability comparable to intra-vineyard variability. Some of the changes in the fungal communities were attributed to environmental factors (plant-available P) and location of the vineyard, although the latter could also have been influenced by an unmeasured environmental factor. A total of 27 taxa of fungi were identified, including taxa from Glomus group B, based on the sequencing of 18S rDNA. Sequencing of the internal transcribed spacer rDNA yielded 30 different fungal taxa, which comprised eight different Glomeromycota taxa, including Glomus sinuosum and Glomus indicum. To our knowledge, this is the first report of grapevine colonisation by G. indicum.

  11. Phylogeny of the glomeromycota (arbuscular mycorrhizal fungi): recent developments and new gene markers.

    PubMed

    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.

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

    PubMed

    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.

  13. Establishment of Vesicular-Arbuscular Mycorrhizal Fungi and Other Microorganisms on a Beach Replenishment Site in Florida †

    PubMed Central

    Sylvia, D. M.; Will, M. E.

    1988-01-01

    Beach replenishment is a widely used method of controlling coastal erosion. To reduce erosional losses from wind, beach grasses are often planted on the replenishment sands. However, there is little information on the microbial populations in this material that may affect plant establishment and growth. The objectives of this research were to document changes in the populations of vesicular-arbuscular mycorrhizal (VAM) fungi and other soil microorganisms in replenishment materials and to determine whether roots of transplanted beach grasses become colonized by beneficial microbes. The study was conducted over a 2-year period on a replenishment project in northeastern Florida. Three sampling locations were established at 1-km intervals along the beach. Each location consisted of three plots: an established dune, replenishment sand planted with Uniola paniculata and Panicum sp., and replenishment sand left unplanted. Fungal and bacterial populations increased rapidly in the rhizosphere of beach grasses in the planted plots. However, no bacteria were recovered that could fix significant amounts of N2. The VAM fungi established slowly on the transplanted grasses. Even after two growing seasons, levels of root colonization and sporulation were significantly below those found in the established dune. There was a shift in the dominant VAM fungi found in the planted zone with respect to those in the established dunes. The most abundant species recovered from the established dunes were Glomus deserticola, followed by Acaulospora scrobiculata and Scutellospora weresubiae. The VAM fungi that colonized the planted zone most rapidly were Glomus globiferum, followed by G. deserticola and Glomus aggregatum. PMID:16347547

  14. Assessing the diversity of arbuscular mycorrhizal fungi in semiarid shrublands dominated by Artemisia tridentata ssp. wyomingensis.

    PubMed

    Carter, Keith A; Smith, James F; White, Merlin M; Serpe, Marcelo D

    2014-05-01

    Variation in the abiotic environment and host plant preferences can affect the composition of arbuscular mycorrhizal (AMF) assemblages. This study analyzed the AMF taxa present in soil and seedlings of Artemisia tridentata ssp. wyomingensis collected from sagebrush steppe communities in southwestern Idaho, USA. Our aims were to determine the AMF diversity within and among these communities and the extent to which preferential AMF-plant associations develop during seedling establishment. Mycorrhizae were identified using molecular methods following DNA extraction from field and pot culture samples. The extracted DNA was amplified using Glomeromycota specific primers, and identification of AMF was based on phylogenetic analysis of sequences from the large subunit-D2 rDNA region. The phylogenetic analyses revealed seven phylotypes, two within the Claroideoglomeraceae and five within the Glomeraceae. Four phylotypes clustered with known species including Claroideoglomus claroideum, Rhizophagus irregularis, Glomus microaggregatum, and Funneliformis mosseae. The other three phylotypes were similar to several published sequences not included in the phylogenetic analysis, but all of these were from uncultured and unnamed glomeromycetes. Pairwise distance analysis revealed some phylotypes with high genetic variation. The most diverse was the phylotype that included R. irregularis, which contained sequences showing pairwise differences up to 12 %. Most of the diversity in AMF sequences occurred within sites. The smaller genetic differentiation detected among sites was correlated with differences in soil texture. In addition, multiplication in pot cultures led to differentiation of AMF communities. Comparison of sequences obtained from the soil with those from A. tridentata roots revealed no significant differences between the AMF present in these samples. Overall, the sites sampled were dominated by cosmopolitan AMF taxa, and young seedlings of A. tridentata ssp

  15. [Effects of Arbuscular Mycorrhizal Fungi on the Growth of Reeds in Wetland Soils with Different Salt Content].

    PubMed

    Guo, Jiang-yuan; Guo, Wei; Bi, Na; Fu, Rui-ying; Zhao, Wen-jing; Zhao, Ren-xin; Wang, Li-xin

    2015-04-01

    A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal (AM) fungi Claroideoglomus etunicatum (CE), Rhizophagus intraradices (RI), Funneliformis mosseae (FM) and Glomus versiforme (GV) on AM colonization rate, biomass, mineral nutrient uptake, C: N: P ratios and Na and Cl- concentrations of reeds (Phragmites australis) grown in saline and non-saline wetland soils. The aim was to provide a technical basis for the ecological revegetation and salinity restoration of wetland ecosystem. The results indicated that symbiotic associations were successfully established between the four isolates and reeds grown in the two types of wetland soils. The average AM colonization rates ranged from 2.5% to 38%. The mean root colonization rate of CE was significantly higher than those of the other three isolates. There were no significant differences in root colonization rates between saline and non-saline wetland soils. The biomass and nutrient contents of reeds grown in non-saline wetland soils were significantly higher than those grown in saline wetland soils. However, Na+ and Cl- concentrations of reeds grown in non-saline wetland soils were significantly lower than those grown in saline wetland soils. In non-saline wetland soils, inoculation with GV significantly increased the shoot dry weight and the shoot N, P, K, Ca and Mg contents of reeds. Inoculation with GV and RI significantly improved the root P and K contents of reeds. Inoculation with the four AM fungi significantly reduced the shoot N: P ratios. Inoculation with FM and GV significantly reduced the root C : N and C : P ratios. Inoculation with the four AM fungi significantly reduced the shoot Cl- concentrations. Inoculation with RI significantly reduced the shoot Na+ concentrations. In saline wetland soils, inoculation with AM fungi had no significant effect on the biomass, mineral nutrient uptake and Na+ and Cl- concentrations of reeds. The results demonstrated that the four AM

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A greenhouse experiment was conducted to study the expression of two phosphate (P) transporter genes ZEAma:Pht1;3 (epidermal-expressed) and ZEAma:Pht1;6 (AM specific induced, and expressed around arbuscules) in maize root to colonization by different arbuscular mycorrhizal (AM) fungal inoculants. No...

  17. Spore population, colonization, species diversity and factors influencing the association of arbuscular mycorrhizal fungi with litchi trees in India.

    PubMed

    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. PMID:26930865

  18. Diversity of Arbuscular Mycorrhizal Fungi Associated with a Sb Accumulator Plant, Ramie (Boehmeria nivea), in an Active Sb Mining.

    PubMed

    Wei, Yuan; Chen, ZhiPeng; Wu, FengChang; Li, JiNing; ShangGuan, YuXian; Li, FaSheng; Zeng, Qing Ru; Hou, Hong

    2015-08-01

    Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the symbiosis of AMF associated with an antimony (Sb) accumulator plant under natural conditions. Therefore, the objective of this study was to investigate the colonization and molecular diversity of AMF associated with the Sb accumulator ramie (Boehmeria nivea) growing in Sb-contaminated soils. Four Sb mine spoils and one adjacent reference area were selected from Xikuangshan in southern China. PCR-DGGE was used to analyze the AMF community composition in ramie roots. Morphological identification was also used to analyze the species in the rhizosphere soil of ramie. Results obtained showed that mycorrhizal symbiosis was established successfully even in the most heavily polluted sites. From the unpolluted site Ref to the highest polluted site T4, the spore numbers and AMF diversity increased at first and then decreased. Colonization increased consistently with the increasing Sb concentrations in the soil. A total of 14 species were identified by morphological analysis. From the total number of species, 4 (29%) belonged to Glomus, 2 (14%) belonged to Acaulospora, 2 (14%) belonged to Funneliformis, 1 (7%) belonged to Claroideoglomus, 1 (7%) belonged to Gigaspora, 1 (7%) belonged to Paraglomus, 1 (7%) belonging to Rhizophagus, 1 (7%) belonging to Sclervocystis, and 1 (7%) belonged to Scutellospora. Some AMF sequences were present even in the most polluted site. Morphological identification and phylogenetic analysis both revealed that most species were affiliated withGlomus, suggesting that Glomus was the dominant genus in this AMF community. This study demonstrated that ramie associated with AMF may have great potential for remediation of Sb-contaminated soils.

  19. Studies on the diversity of arbuscular mycorrhizal fungi and the efficacy of two native isolates in a highly alkaline anthropogenic sediment.

    PubMed

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

    2005-12-01

    A field survey of the arbuscular mycorrhizal status of herbaceous plant species was conducted in a highly alkaline anthropogenic sediment resulting from the disposal of waste from an acetylene and polyvinyl chloride factory. Most plant species found at the site were mycorrhizal and the dominant mycotrophic plant species was Conyza bilbaoana. Fungal species richness was assessed by identification of spores extracted from the sediment and from continuously propagated trap pot cultures. All of the six species of arbuscular mycorrhizal fungi (AMF) found were from the genus Glomus. Glomus intraradices and G. mosseae were found in field-collected sediment samples and also occurred most frequently in trap cultures. To test the symbiotic effectiveness of these two fungi, seedlings of C. bilbaoana were inoculated with either native G. intraradices BEG163 or G. mosseae BEG198 and non-native G. intraradices BEG75 or G. mosseae BEG25 isolates in sterile and non-sterile sediment collected from the study site. All four isolates were able to colonise C. bilbaoana. However, AMF native to the target sediments were generally more effective than the non-native fungi in promoting plant establishment and growth under highly alkaline conditions. The non-native G. intraradices was, however, more effective than the non-native G. mosseae. The results of this study suggest the use of adapted AMF as inoculants for phytorestoration of alkaline anthropogenic-stressed sediments. PMID:16007472

  20. Interactive Effects of Arbuscular Mycorrhizal Fungi and Copper Stress on Flowering Phenology and Reproduction of Elsholtzia splendens

    PubMed Central

    Jin, Zexin; Li, Junmin; Li, Yueling

    2015-01-01

    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 of E. splendens. PMID:26709921

  1. Alleviation of cadmium stress in Solanum lycopersicum L. by arbuscular mycorrhizal fungi via induction of acquired systemic tolerance.

    PubMed

    Hashem, Abeer; Abd Allah, E F; Alqarawi, A A; Al Huqail, Asma A; Egamberdieva, D; Wirth, S

    2016-03-01

    Experiments were conducted to evaluate cadmium (Cd) stress-induced changes in growth, antioxidants and lipid composition of Solanum lycopersicum with and without arbuscular mycorrhizal fungi (AMF). Cadmium stress (50 μM) caused significant changes in the growth and physio-biochemical attributes studied. AMF mitigated the deleterious impact of Cd on the parameters studied. Cadmium stress increased malonaldehyde and hydrogen peroxide production but AMF reduced these parameters by mitigating oxidative stress. The activity of antioxidant enzymes enhanced under Cd treatment and AMF inoculation further enhanced their activity, thus strengthening the plant's defense system. Proline and phenol content increased in Cd-treated as well as AMF-inoculated plants providing efficient protection against Cd stress. Cadmium treatment resulted in great alterations in the main lipid classes leading to a marked change in their composition. Cadmium stress caused a significant reduction in polyunsaturated fatty acids resulting in enhanced membrane leakage. The present study supports the use of AMF as a biological means to ameliorate Cd stress-induced changes in tomato. PMID:26981010

  2. The molecular diversity of arbuscular mycorrhizal fungi in the arsenic mining impacted sites in Hunan Province of China.

    PubMed

    Sun, Yuqing; Zhang, Xin; Wu, Zhaoxiang; Hu, Yajun; Wu, Songlin; Chen, Baodong

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) can establish a mutualistic association with most terrestrial plants even in heavy metal contaminated environments. It has been documented that high concentrations of toxic metals, such as arsenic (As) in soil could adversely affect the diversity and function of AMF. However, there are still gaps in understanding the community composition of AMF under long-term As contaminations. In the present study, six sampling sites with different As concentrations were selected in the Realgar mining area in Hunan Province of China. The AMF biodiversity in the rhizosphere soils of the dominant plant species was investigated by sequencing the nuclear small subunit ribosomal RNA (SSU rRNA) gene fragments using 454-pyrosequencing technique. A total of 11 AMF genera were identified, namely Rhizophagus, Glomus, Funneliformis, Acaulospora, Diversispora, Claroideoglomus, Scutellopora, Gigaspora, Ambispora, Praglomus, and Archaeospora, among which Glomus, Rhizophagus, and Claroideoglomus clarodeum were detected in all sampling sites, and Glomus was the dominant AMF genus in the Realgar mining area. Redundancy analysis indicated that soil pH, total As and Cd concentrations were the main factors influencing AMF community structure. There was a negative correlation between the AMF species richness and the total As concentration in the soil, but no significant correlation between the Shannon-Wiener index of the AMF and plants. Our study showed that high As concentrations can exert a selective effect on the AMF populations. PMID:26899650

  3. Interactive Effects of Arbuscular Mycorrhizal Fungi and Copper Stress on Flowering Phenology and Reproduction of Elsholtzia splendens.

    PubMed

    Jin, Zexin; Li, Junmin; Li, Yueling

    2015-01-01

    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 of E. splendens. PMID:26709921

  4. Effect of Arbuscular Mycorrhizal Fungi on the Growth and Polyphenol Profile of Marjoram, Lemon Balm, and Marigold.

    PubMed

    Engel, Rita; Szabó, Krisztina; Abrankó, László; Rendes, Kata; Füzy, Anna; Takács, Tünde

    2016-05-18

    The aim of this study is to examine the effect of arbuscular mycorrhizal fungi (AMF) colonization on biomass, polyphenol profile, and content of economically important herbs. A pot experiment was performed with marjoram, lemon balm, and marigold applying a commercially available AMF mixture for inoculation. Major polyphenols were identified using HPLC-UV-ESI-qTOFMS on the basis of their UV-vis and mass spectral characteristics, and selected ones were quantified. We showed that AMF can provide different services for each herb. Marjoram had the highest level of fungal colonization (82 M%) followed by lemon balm (62 M%) and marigold (17 M%). AMF inoculation significantly increased the biomass of marjoram (1.5-fold), the number of marigold flowers (1.2-fold), and the yield of rosmarinic acid and lithospermic acid isomers of marjoram (1.5-fold) and lemon balm (1.2-fold). Therefore, the quantity and quality of plant material could be improved by the application of optimized AMF inoculum. PMID:27096876

  5. Impact of weed control on arbuscular mycorrhizal fungi in a tropical agroecosystem: a long-term experiment.

    PubMed

    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.

  6. The molecular diversity of arbuscular mycorrhizal fungi in the arsenic mining impacted sites in Hunan Province of China.

    PubMed

    Sun, Yuqing; Zhang, Xin; Wu, Zhaoxiang; Hu, Yajun; Wu, Songlin; Chen, Baodong

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) can establish a mutualistic association with most terrestrial plants even in heavy metal contaminated environments. It has been documented that high concentrations of toxic metals, such as arsenic (As) in soil could adversely affect the diversity and function of AMF. However, there are still gaps in understanding the community composition of AMF under long-term As contaminations. In the present study, six sampling sites with different As concentrations were selected in the Realgar mining area in Hunan Province of China. The AMF biodiversity in the rhizosphere soils of the dominant plant species was investigated by sequencing the nuclear small subunit ribosomal RNA (SSU rRNA) gene fragments using 454-pyrosequencing technique. A total of 11 AMF genera were identified, namely Rhizophagus, Glomus, Funneliformis, Acaulospora, Diversispora, Claroideoglomus, Scutellopora, Gigaspora, Ambispora, Praglomus, and Archaeospora, among which Glomus, Rhizophagus, and Claroideoglomus clarodeum were detected in all sampling sites, and Glomus was the dominant AMF genus in the Realgar mining area. Redundancy analysis indicated that soil pH, total As and Cd concentrations were the main factors influencing AMF community structure. There was a negative correlation between the AMF species richness and the total As concentration in the soil, but no significant correlation between the Shannon-Wiener index of the AMF and plants. Our study showed that high As concentrations can exert a selective effect on the AMF populations.

  7. Unusually large contribution of arbuscular mycorrhizal fungi tosoil organic matter pools in tropical forest soils. Plant and soils

    SciTech Connect

    Rilling, M.C.; Wright, S.F.; Nicholas, K.A.; Schmidt, W.F.; Torn,M.S.

    2000-07-12

    The origins and composition of soil organic matter (SOM) are still largely uncertain. Arbuscular mycorrhizal fungi (AMF) are recognized as indirect contributors through their influence on soil aggregation, plant physiology, and plant community composition. Here we present evidence that AMF can also make large, direct contributions to SOM. Glomalin, a recently discovered glycoprotein produced by AMF hyphae, was detected in tropical soils in concentrations of over 60 mg cm-3. Along a chronosequence of soils spanning ages from 300 to 4.1 Mio years, a pattern of glomalin concentrations is consistent with the hypothesis that this protein accumulates in soil. Carbon dating of glomalin indicated turnover at time scales of several years to decades, much longer than the turnover of AMF hyphae (which is assumed to be on the order of days to weeks). This suggests that contributions of mycorrhizae to soil carbon storage based on hyphal biomass in soil and roots may be an underestimate. The amount of C and N in glomalin represented a sizeable amount (ca. 4-5 percent) of total soil C and N in the oldest soils. Our results thus indicate that microbial (fungal) carbon that is not derived from above- or below-ground litter can make a significant contribution to soil carbon and nitrogen pools and can far exceed the contributions of soil microbial biomass (ranging from 0.08 to 0.2 percent of total C for the oldest soils).

  8. Communities of arbuscular mycorrhizal fungi in Pyrus pyrifolia var. culta (Japanese pear) and an understory herbaceous plant Plantago asiatica.

    PubMed

    Yoshimura, Yuko; Ido, Akifumi; Matsumoto, Teruyuki; Yamato, Masahide

    2013-01-01

    We investigated communities of arbuscular mycorrhizal fungi (AMF) in the fine roots of Pyrus pyrifolia var. culta, and Plantago asiatica to consider the relationship between orchard trees and herbaceous plants in AMF symbioses. The AMF communities were analyzed on the basis of the partial fungal DNA sequences of the nuclear small subunit ribosomal RNA gene (SSU rDNA), which were amplified using the AMF-specific primers AML1 and AML2. Phylogenetic analysis showed that the obtained AMF sequences were divided into 23 phylotypes. Among them, 12 phylotypes included AMF from both host plants, and most of the obtained sequences (689/811) were affiliated to them. Canonical correspondence analysis showed that the host plant species did not have a significant effect on the distribution of AMF phylotypes, whereas the effects of sampling site, soil total C, soil total N and soil-available P were significant. It was also found that the mean observed overlaps of AMF phylotypes between the paired host plants in the same soil cores (27.1% of phylotypes shared) were significantly higher than the mean 1,000 simulated overlaps (14.2%). Furthermore, the same AMF sequences (100% sequence identity) were detected from both host plants in 8/12 soil cores having both roots. Accordingly, we concluded that Py. pyrifolia and Pl. asiatica examined shared some AMF communities, which suggested that understory herbaceous plants may function as AMF inoculum sources for orchard trees. PMID:23614902

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

    PubMed

    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.

  10. The interaction with arbuscular mycorrhizal fungi or Trichoderma harzianum alters the shoot hormonal profile in melon plants.

    PubMed

    Martínez-Medina, Ainhoa; Roldán, Antonio; Albacete, Alfonso; Pascual, Jose A

    2011-02-01

    Arbuscular mycorrhizal fungi (AMF) and Trichoderma harzianum are known to affect plant growth and disease resistance through interaction with phytohormone synthesis or transport in the plant. Cross-talk between these microorganisms and their host plants normally occurs in nature and may affect plant resistance. Simultaneous quantification in the shoots of melon plants revealed significant changes in the levels of several hormones in response to inoculation with T. harzianum and two different AMF (Glomus intraradices and Glomus mosseae). Analysis of zeatin (Ze), indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), jasmonic acid (JA) and abscisic acid (ABA) in the shoot showed common and divergent responses of melon plants to G. intraradices and G. mosseae. T. harzianum effected systemic increases in Ze, IAA, ACC, SA, JA and ABA. The interaction of T. harzianum and the AMF with the plant produced a characteristic hormonal profile, which differed from that produced by inoculation with each microorganism singly, suggesting an attenuation of the plant response, related to the hormones SA, JA and ethylene. These results are discussed in relation to their involvement in biomass allocation and basal resistance against Fusarium wilt. PMID:21145086

  11. Violets of the section Melanium, their colonization by arbuscular mycorrhizal fungi and their occurrence on heavy metal heaps.

    PubMed

    Słomka, A; Kuta, E; Szarek-Łukaszewska, G; Godzik, B; Kapusta, P; Tylko, G; Bothe, H

    2011-07-15

    Violets of the sections Melanium were examined for their colonization by arbuscular mycorrhizal fungi (AMF). Heartsease (Viola tricolor) from several heavy metal soils was AMF-positive at many sites but not at extreme biomes. The zinc violets Viola lutea ssp. westfalica (blue zinc violet) and ssp. calaminaria (yellow zinc violet) were always AMF-positive on heavy metal soils as their natural habitats. As shown for the blue form, zinc violets germinate independently of AMF and can be grown in non-polluted garden soils. Thus the zinc violets are obligatorily neither mycotrophs nor metalophytes. The alpine V. lutea, likely ancestor of the zinc violets, was at best poorly colonized by AMF. As determined by atomic absorption spectrometry, the contents of Zn and Pb were lower in AMF colonized plants than in the heavy metal soils from where the samples had been taken. AMF might prevent the uptake of toxic levels of heavy metals into the plant organs. Dithizone staining indicated a differential deposition of heavy metals in tissues of heartsease. Leaf hairs were particularly rich in heavy metals, indicating that part of the excess of heavy metals is sequestered into these cells.

  12. [Effects of arbuscular mycorrhizal fungi on the growth and fruit quality of plastic greenhouse Cucumis sativus L].

    PubMed

    Lü, Guiyun; Chen, Guilin; Qi, Guohui; Gao, Zhikui

    2006-12-01

    In this paper, arbuscular mycorrhizal fungi (AMF) Glomus versiforme (GV), Glomus mosseae (GM), Glomus intraradices (GI) and their mixtures were applied to inoculate plastic greenhouse Cucumis sativus seedlings to investigate the effects of AMF on C. sativus growth, development, yield, and quality. The results showed that all test AMF could form mycorrhiza with cucumber roots, and the infected rate reached 41.74% - 55.69%. Compared with the control, treatments GV, GM, GM + GV, GM + GV + GI and GV + GI enhanced the healthy seedling index by 58.14% - 123.6%, and increased early yield by 21.71% - 37.87% and total yield by 19.72% - 34.41%. AMF also improved fruit quality. The Vc content of cucumber fruit increased by 22.84% and 21.95% in treatments GM + GV and GV + GI, soluble sugar content increased by 13.29%, 8.25%, and 10.20% in treatments GV, GI and GV + GI, and amino acid content increased by 47.66% and 23.19% in treatments GV and GM + GI, respectively, while soluble protein content increased by 17.67% - 34.29% in all AMF treatments. The results suggested that AMF inoculation could significantly promote the seedling growth of cucumber and improve its fruit quality, and the effects differed with different AMF and their combinations.

  13. Role of extrinsic arbuscular mycorrhizal fungi in heavy metal-contaminated wetlands with various soil moisture levels.

    PubMed

    Zheng, S; Wang, C; Shen, Z; Quan, Y; Liu, X

    2015-01-01

    This study presents an efficient heavy metal (HM) control method in HM-contaminated wetlands with varied soil moisture levels through the introduction of extrinsic arbuscular mycorrhizal fungi (AMF) into natural wetland soil containing indigenous AMF species. A pot culture experiment was designed to determine the effect of two soil water contents (5-8% and 25-30%), five extrinsic AMF inoculants (Glomus mosseae, G. clarum, G. claroideum, G. etunicatum, and G. intraradices), and HM contamination on root colonization, plant growth, and element uptake of common reed (Phragmites australis (Cav.) Trin. ex Steudel) plantlets in wetland soils. This study showed the prevalence of mycorrhizae in the roots of all P. australis plantlets, regardless of extrinsic AMF inoculations, varied soil moisture or HM levels. It seems that different extrinsic AMF inoculations effectively lowered HM concentrations in the aboveground tissues of P. australis at two soil moisture levels. However, metal species, metal concentrations, and soil moisture should also be very important factors influencing the elemental uptake performance of plants in wetland ecosystems. Besides, the soil moisture level significantly influenced plant growth (including height, and shoot and root dry weight (DW)), and extrinsic AMF inoculations differently affected shoot DW.

  14. Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China.

    PubMed

    Wei, Yuan; Chen, Zhipeng; Wu, Fengchang; Hou, Hong; Li, Jining; Shangguan, Yuxian; Zhang, Juan; Li, Fasheng; Zeng, Qingru

    2015-03-01

    Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.

  15. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved

    PubMed Central

    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. PMID:26635750

  16. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes.

    PubMed

    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.

  17. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved.

    PubMed

    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. PMID:26635750

  18. Alleviation of cadmium stress in Solanum lycopersicum L. by arbuscular mycorrhizal fungi via induction of acquired systemic tolerance

    PubMed Central

    Hashem, Abeer; Abd_Allah, E.F.; Alqarawi, A.A.; Al Huqail, Asma A.; Egamberdieva, D.; Wirth, S.

    2015-01-01

    Experiments were conducted to evaluate cadmium (Cd) stress-induced changes in growth, antioxidants and lipid composition of Solanum lycopersicum with and without arbuscular mycorrhizal fungi (AMF). Cadmium stress (50 μM) caused significant changes in the growth and physio-biochemical attributes studied. AMF mitigated the deleterious impact of Cd on the parameters studied. Cadmium stress increased malonaldehyde and hydrogen peroxide production but AMF reduced these parameters by mitigating oxidative stress. The activity of antioxidant enzymes enhanced under Cd treatment and AMF inoculation further enhanced their activity, thus strengthening the plant’s defense system. Proline and phenol content increased in Cd-treated as well as AMF-inoculated plants providing efficient protection against Cd stress. Cadmium treatment resulted in great alterations in the main lipid classes leading to a marked change in their composition. Cadmium stress caused a significant reduction in polyunsaturated fatty acids resulting in enhanced membrane leakage. The present study supports the use of AMF as a biological means to ameliorate Cd stress-induced changes in tomato. PMID:26981010

  19. Modularity reveals the tendency of arbuscular mycorrhizal fungi to interact differently with generalist and specialist plant species in gypsum soils.

    PubMed

    Torrecillas, Emma; del Mar Alguacil, Maria; Roldán, Antonio; Díaz, Gisela; Montesinos-Navarro, Alicia; Torres, Maria Pilar

    2014-09-01

    Patterns in plant-soil biota interactions could be influenced by the spatial distribution of species due to soil conditions or by the functional traits of species. Gypsum environments usually constitute a mosaic of heterogeneous soils where gypsum and nongypsum soils are imbricated at a local scale. A case study of the interactions of plants with arbuscular mycorrhizal fungi (AMF) in gypsum environments can be illustrative of patterns in biotic interactions. We hypothesized that (i) soil characteristics might affect the AMF community and (ii) there are differences between the AMF communities (modules) associated with plants exclusive to gypsum soils (gypsophytes) and those associated with plants that show facultative behavior on gypsum and/or marly-limestone soils (gypsovags). We used indicator species and network analyses to test for differences between the AMF communities harbored in gypsophyte and gypsovag plants. We recorded 46 operational taxonomic units (OTUs) belonging to nine genera of Glomeromycota. The indicator species analysis showed two OTUs preferentially associating with gypsum soils and three OTUs preferentially associating with marly-limestone soils. Modularity analysis revealed that soil type can be a major factor shaping AMF communities, and some AMF groups showed a tendency to interact differently with plants that had distinct ecological strategies (gypsophytes and gypsovags). Characterization of ecological networks can be a valuable tool for ascertaining the potential influence of above- and below-ground biotic interactions (plant-AMF) on plant community composition. PMID:24973074

  20. Modularity Reveals the Tendency of Arbuscular Mycorrhizal Fungi To Interact Differently with Generalist and Specialist Plant Species in Gypsum Soils

    PubMed Central

    Torrecillas, Emma; del Mar Alguacil, Maria; Roldán, Antonio; Díaz, Gisela; Montesinos-Navarro, Alicia

    2014-01-01

    Patterns in plant–soil biota interactions could be influenced by the spatial distribution of species due to soil conditions or by the functional traits of species. Gypsum environments usually constitute a mosaic of heterogeneous soils where gypsum and nongypsum soils are imbricated at a local scale. A case study of the interactions of plants with arbuscular mycorrhizal fungi (AMF) in gypsum environments can be illustrative of patterns in biotic interactions. We hypothesized that (i) soil characteristics might affect the AMF community and (ii) there are differences between the AMF communities (modules) associated with plants exclusive to gypsum soils (gypsophytes) and those associated with plants that show facultative behavior on gypsum and/or marly-limestone soils (gypsovags). We used indicator species and network analyses to test for differences between the AMF communities harbored in gypsophyte and gypsovag plants. We recorded 46 operational taxonomic units (OTUs) belonging to nine genera of Glomeromycota. The indicator species analysis showed two OTUs preferentially associating with gypsum soils and three OTUs preferentially associating with marly-limestone soils. Modularity analysis revealed that soil type can be a major factor shaping AMF communities, and some AMF groups showed a tendency to interact differently with plants that had distinct ecological strategies (gypsophytes and gypsovags). Characterization of ecological networks can be a valuable tool for ascertaining the potential influence of above- and below-ground biotic interactions (plant-AMF) on plant community composition. PMID:24973074

  1. Effect of Arbuscular Mycorrhizal Fungi on the Growth and Polyphenol Profile of Marjoram, Lemon Balm, and Marigold.

    PubMed

    Engel, Rita; Szabó, Krisztina; Abrankó, László; Rendes, Kata; Füzy, Anna; Takács, Tünde

    2016-05-18

    The aim of this study is to examine the effect of arbuscular mycorrhizal fungi (AMF) colonization on biomass, polyphenol profile, and content of economically important herbs. A pot experiment was performed with marjoram, lemon balm, and marigold applying a commercially available AMF mixture for inoculation. Major polyphenols were identified using HPLC-UV-ESI-qTOFMS on the basis of their UV-vis and mass spectral characteristics, and selected ones were quantified. We showed that AMF can provide different services for each herb. Marjoram had the highest level of fungal colonization (82 M%) followed by lemon balm (62 M%) and marigold (17 M%). AMF inoculation significantly increased the biomass of marjoram (1.5-fold), the number of marigold flowers (1.2-fold), and the yield of rosmarinic acid and lithospermic acid isomers of marjoram (1.5-fold) and lemon balm (1.2-fold). Therefore, the quantity and quality of plant material could be improved by the application of optimized AMF inoculum.

  2. Effect of biosolids-derived triclosan and triclocarban on the colonization of plant roots by arbuscular mycorrhizal fungi.

    PubMed

    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 (p<0.05) on lettuce roots. Biosolids-derived triclosan and triclocarban did not inhibit the colonization of crop plant roots by AMF.

  3. Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

    PubMed

    Jiang, Qiu-Yun; Zhuo, Feng; Long, Shi-Hui; Zhao, Hai-Di; Yang, Dan-Jing; Ye, Zhi-Hong; Li, Shao-Shan; Jing, Yuan-Xiao

    2016-01-01

    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. PMID:26892768

  4. Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

    NASA Astrophysics Data System (ADS)

    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.

  5. Shifts in the phylogenetic structure of arbuscular mycorrhizal fungi in response to experimental nitrogen and carbon dioxide additions.

    PubMed

    Mueller, Rebecca C; Bohannan, Brendan J M

    2015-09-01

    Global N inputs and atmospheric CO2 concentrations have increased as a result of human activities, and are predicted to increase along with population growth, with potentially negative effects on biodiversity. Using taxonomic and phylogenetic measures, we examined the response of arbuscular mycorrhizal fungi (AMF) to experimental manipulations of N and CO2 at the Jasper Ridge Global Change Experiment. No significant interactions between N and CO2 were observed, but individual effects of N and CO2 were found. Elevated CO2 resulted in changes in phylogenetic similarity, and a shift to phylogenetic clustering of AMF communities. N addition resulted in higher phylogenetic diversity and evenness, with no shifts in community composition and no significant signal for phylogenetic clustering. N addition resulted in an increase in both available N and the N:P ratio in N-amended plots, which suggests that changing patterns of nutrient limitation could have lead to altered species interactions. These findings suggest that elevated levels of N and CO2 altered patterns of AMF community assembly, with potential effects on ecosystem function. PMID:25990297

  6. The influence of arbuscular mycorrhizal fungi inoculation on yam (Dioscorea spp.) tuber weights and secondary metabolite content

    PubMed Central

    Lu, Fun-Chi; Wang, Chun-Li

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are widely distributed in nature. They live in the roots of higher plants, in a symbiotic relationship. In this study, five commercial species of yams (Dioscorea spp.) were inoculated with six species of AMF, Glomus clarum, G. etunicatum, G. fasciculatum, Gigaspora sp., G. mosseae, and Acaulospora sp., in field cultivation conditions to investigate the influence of AMF inoculation on tuber weights and secondary metabolite content in yam tubers. The results showed that mycorrhizae formation rates ranged from 63.33% to 90%. G. etunicatum inoculation treatment increased the tube weights of the five species of yam tubers by 39%, 35%, 20%, 56%, and 40% for Tainung 1, Tainung 2, Ercih, Zihyuxieshu, and Tainung 5, respectively. The content of secondary metabolites, such as polyphenols, flavonoids, and anthocyanin, was significantly increased by the AMF treatment in tuber flesh and peel of all the tested yam species. Specifically, the maximums exchange of secondary metabolite contents increased to 40%, 42%, and 106% for polyphenols, flavonoids, and anthocyanin, respectively, in the tuber fresh. This study revealed that different species of yam had varying degrees of affinity with various AMF species; selecting effective AMF species is necessary to facilitate yam growth and improve the quality and quantity of yam tubers. PMID:26421239

  7. Impact of weed control on arbuscular mycorrhizal fungi in a tropical agroecosystem: a long-term experiment.

    PubMed

    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. PMID:22584877

  8. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes.

    PubMed

    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. PMID:24895680

  9. The influence of arbuscular mycorrhizal fungi inoculation on yam (Dioscorea spp.) tuber weights and secondary metabolite content.

    PubMed

    Lu, Fun-Chi; Lee, Chen-Yu; Wang, Chun-Li

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are widely distributed in nature. They live in the roots of higher plants, in a symbiotic relationship. In this study, five commercial species of yams (Dioscorea spp.) were inoculated with six species of AMF, Glomus clarum, G. etunicatum, G. fasciculatum, Gigaspora sp., G. mosseae, and Acaulospora sp., in field cultivation conditions to investigate the influence of AMF inoculation on tuber weights and secondary metabolite content in yam tubers. The results showed that mycorrhizae formation rates ranged from 63.33% to 90%. G. etunicatum inoculation treatment increased the tube weights of the five species of yam tubers by 39%, 35%, 20%, 56%, and 40% for Tainung 1, Tainung 2, Ercih, Zihyuxieshu, and Tainung 5, respectively. The content of secondary metabolites, such as polyphenols, flavonoids, and anthocyanin, was significantly increased by the AMF treatment in tuber flesh and peel of all the tested yam species. Specifically, the maximums exchange of secondary metabolite contents increased to 40%, 42%, and 106% for polyphenols, flavonoids, and anthocyanin, respectively, in the tuber fresh. This study revealed that different species of yam had varying degrees of affinity with various AMF species; selecting effective AMF species is necessary to facilitate yam growth and improve the quality and quantity of yam tubers.

  10. Arbuscular mycorrhizal fungi associated with Artemisia umbelliformis Lam, an endangered aromatic species in Southern French Alps, influence plant P and essential oil contents.

    PubMed

    Binet, Marie-Noëlle; van Tuinen, Diederik; Deprêtre, Nicolas; Koszela, Nathalie; Chambon, Catherine; Gianinazzi, Silvio

    2011-08-01

    Root colonization by arbuscular mycorrhizal (AM) fungi of Artemisia umbelliformis, investigated in natural and cultivated sites in the Southern Alps of France, showed typical structures (arbuscules, vesicles, hyphae) as well as spores and mycelia in its rhizosphere. Several native AM fungi belonging to different Glomeromycota genera were identified as colonizers of A. umbelliformis roots, including Glomus tenue, Glomus intraradices, G. claroideum/etunicatum and a new Acaulospora species. The use of the highly mycorrhizal species Trifolium pratense as a companion plant impacted positively on mycorrhizal colonization of A. umbelliformis under greenhouse conditions. The symbiotic performance of an alpine microbial community including native AM fungi used as inoculum on A. umbelliformis was evaluated in greenhouse conditions by comparison with mycorrhizal responses of two other alpine Artemisia species, Artemisia glacialis and Artemisia genipi Weber. Contrary to A. genipi Weber, both A. umbelliformis and A. glacialis showed a significant increase of P concentration in shoots. Volatile components were analyzed by GC-MS in shoots of A. umbelliformis 6 months after inoculation. The alpine microbial inoculum increased significantly the percentage of E-β-ocimene and reduced those of E-2-decenal and (E,E)-2-4-decadienal indicating an influence of alpine microbial inoculum on essential oil production. This work provides practical indications for the use of native AM fungi for A. umbelliformis field culture. PMID:21243378

  11. Arbuscular mycorrhizal fungi associated with Artemisia umbelliformis Lam, an endangered aromatic species in Southern French Alps, influence plant P and essential oil contents.

    PubMed

    Binet, Marie-Noëlle; van Tuinen, Diederik; Deprêtre, Nicolas; Koszela, Nathalie; Chambon, Catherine; Gianinazzi, Silvio

    2011-08-01

    Root colonization by arbuscular mycorrhizal (AM) fungi of Artemisia umbelliformis, investigated in natural and cultivated sites in the Southern Alps of France, showed typical structures (arbuscules, vesicles, hyphae) as well as spores and mycelia in its rhizosphere. Several native AM fungi belonging to different Glomeromycota genera were identified as colonizers of A. umbelliformis roots, including Glomus tenue, Glomus intraradices, G. claroideum/etunicatum and a new Acaulospora species. The use of the highly mycorrhizal species Trifolium pratense as a companion plant impacted positively on mycorrhizal colonization of A. umbelliformis under greenhouse conditions. The symbiotic performance of an alpine microbial community including native AM fungi used as inoculum on A. umbelliformis was evaluated in greenhouse conditions by comparison with mycorrhizal responses of two other alpine Artemisia species, Artemisia glacialis and Artemisia genipi Weber. Contrary to A. genipi Weber, both A. umbelliformis and A. glacialis showed a significant increase of P concentration in shoots. Volatile components were analyzed by GC-MS in shoots of A. umbelliformis 6 months after inoculation. The alpine microbial inoculum increased significantly the percentage of E-β-ocimene and reduced those of E-2-decenal and (E,E)-2-4-decadienal indicating an influence of alpine microbial inoculum on essential oil production. This work provides practical indications for the use of native AM fungi for A. umbelliformis field culture.

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

    PubMed Central

    Knappová, Jana; Pánková, Hana; Münzbergová, Zuzana

    2016-01-01

    Background 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. Aims and Methods 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. Key Results 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

  13. Effects of rhizobium, arbuscular mycorrhizal fungi and anion content of simulated rain on subterranean clover.

    PubMed

    Shafer, S R; Schoeneberger, M M; Horton, S J; Davey, C B; Miller, J E

    1996-01-01

    An experiment was conducted to determine the extent to which rhizobia, mycorrhizal fungi, and anions in simulated rain affect plant growth response to acid deposition. Germinating subterranean clover seeds were planted in steam-pasteurized soil in pots and inoculated with Rhizobium leguminosarum, Glomus intraradices, Glomus etunicatum, R. leguminosarum + G. intraradices, R. leguminosarum + G. etunicatum, or no microbial symbionts. Beginning 3 weeks later, plants and the soil surface were exposed to simulated rain in a greenhouse on 3 days week(-1) for 12 weeks. Rain solutions were deionized water amended with background ions only (pH 5.0) or also adjusted to pH 3.0 with HNO3 only, H2SO4 only, or a 50/50 mixture of the two acids. Glomus intraradices colonized plant roots poorly, and G. intraradices-inoculated plants responded like nonmycorrhizal plants to rhizobia and rain treatments. Variation in plant biomass attributable to different rain formulations was strongest for G. etunicatum-inoculated plants, and the effect of rain formulation differed with respect to nodulation by rhizobia. The smallest plants at the end of the experiment were noninoculated plants exposed to rains (0.38 g mean dry weight total for 3 plants pot(-1)). Among nonnodulated plants infected by G. etunicatum, those exposed to HNO3 rain were largest, followed by plants exposed to HNO3 + H2SO4, pH 5.0, and H2SO4 rain, in that order. Among plants inoculated with both R. leguminosarum + G. etunicatum, however, the greatest biomass occurred with pH 5.0 rains, resulting in the largest plants in the study (1.00 g/3 plants). Treatment-related variation among root and shoot biomass data reflected those for whole-plant biomass. Based on quantification of biomass and N concentrations in shoot and root tissues, total N content of plants inoculated with G. etunicatum alone and exposed to the HNO3 + H2SO4 rains was approximately the same as plants inoculated with R. leguminosarum + G. entunicatum and exposed

  14. The Interaction between Arbuscular Mycorrhizal Fungi and Endophytic Bacteria Enhances Plant Growth of Acacia gerrardii under Salt Stress

    PubMed Central

    Hashem, Abeer; Abd_Allah, Elsayed F.; Alqarawi, Abdulaziz A.; Al-Huqail, Asma A.; Wirth, Stephan; Egamberdieva, Dilfuza

    2016-01-01

    Microbes living symbiotically in plant tissues mutually cooperate with each other by providing nutrients for proliferation of the partner organism and have a beneficial effect on plant growth. However, few studies thus far have examined the interactive effect of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) in hostile conditions and their potential to improve plant stress tolerance. In this study, we investigated how the synergistic interactions of endophytic bacteria and AMF affect plant growth, nodulation, nutrient acquisition and stress tolerance of Acacia gerrardii under salt stress. Plant growth varied between the treatments with both single inoculants and was higher in plants inoculated with the endophytic B. subtilis strain than with AMF. Co-inoculated A. gerrardii had a significantly greater shoot and root dry weight, nodule number, and leghemoglobin content than those inoculated with AMF or B. subtilis alone under salt stress. The endophytic B. subtilis could alleviate the adverse effect of salt on AMF colonization. The differences in nitrate and nitrite reductase and nitrogenase activities between uninoculated plants and those inoculated with AMF and B. subtilis together under stress were significant. Both inoculation treatments, either B. subtilis alone or combined with AMF, enhanced the N, P, K, Mg, and Ca contents and phosphatase activities in salt-stressed A. gerrardii tissues and reduced Na and Cl concentration, thereby protecting salt-stressed plants from ionic and osmotic stress-induced changes. In conclusion, our results indicate that endophytic bacteria and AMF contribute to a tripartite mutualistic symbiosis in A. gerrardii and are coordinately involved in the plant adaptation to salt stress tolerance. PMID:27486442

  15. The Interaction between Arbuscular Mycorrhizal Fungi and Endophytic Bacteria Enhances Plant Growth of Acacia gerrardii under Salt Stress.

    PubMed

    Hashem, Abeer; Abd Allah, Elsayed F; Alqarawi, Abdulaziz A; Al-Huqail, Asma A; Wirth, Stephan; Egamberdieva, Dilfuza

    2016-01-01

    Microbes living symbiotically in plant tissues mutually cooperate with each other by providing nutrients for proliferation of the partner organism and have a beneficial effect on plant growth. However, few studies thus far have examined the interactive effect of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) in hostile conditions and their potential to improve plant stress tolerance. In this study, we investigated how the synergistic interactions of endophytic bacteria and AMF affect plant growth, nodulation, nutrient acquisition and stress tolerance of Acacia gerrardii under salt stress. Plant growth varied between the treatments with both single inoculants and was higher in plants inoculated with the endophytic B. subtilis strain than with AMF. Co-inoculated A. gerrardii had a significantly greater shoot and root dry weight, nodule number, and leghemoglobin content than those inoculated with AMF or B. subtilis alone under salt stress. The endophytic B. subtilis could alleviate the adverse effect of salt on AMF colonization. The differences in nitrate and nitrite reductase and nitrogenase activities between uninoculated plants and those inoculated with AMF and B. subtilis together under stress were significant. Both inoculation treatments, either B. subtilis alone or combined with AMF, enhanced the N, P, K, Mg, and Ca contents and phosphatase activities in salt-stressed A. gerrardii tissues and reduced Na and Cl concentration, thereby protecting salt-stressed plants from ionic and osmotic stress-induced changes. In conclusion, our results indicate that endophytic bacteria and AMF contribute to a tripartite mutualistic symbiosis in A. gerrardii and are coordinately involved in the plant adaptation to salt stress tolerance.

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

    PubMed Central

    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

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

    PubMed

    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.

  18. Management of Striga hermonthica on sorghum (Sorghum bicolor) using arbuscular mycorrhizal fungi (Glomus mosae) and NPK fertilizer levels.

    PubMed

    Isah, K M; Kumar, Niranjan; Lagoke, S T O; Atayese, M O

    2013-11-15

    Trials were conducted in the screen house of Niger State College of Agriculture, Mokwa (09 degrees 18'N; 05 degrees 04'E) in the Southern Guinea Savannah agro-ecological zone of Nigeria during October-December, 2008 and January-March, 2009. The objective was to evaluate the effect of management of Striga hermonthica on sorghum (Sorghum bicolor) using Arbuscular mycorrhizal fungi and NPK fertilizer levels. The trials were laid out in split-split plot arrangement in a randomized complete block design. The main-plot treatments consisted of three sorghum varieties; SAMSORG 3, ICSVIII and SAMSORG 14 while the sub-plot treatments consisted of inoculations; Striga mixed with Glomus, Striga only and Glomus only as well as no inoculation control. The sub-sub-plot treatments were made up of NPK fertilizer levels; (100 kg N, 50 kg P2O5, 50 kg K2O ha(-1)), (50 kg N, 50 kg P2O5, 50 kg K2O ha(-1)) and (0 kg N, 0 kg P2O5, 0 kg K2O ha(-1)). The result obtained showed that sorghum variety SAMSORG 3 were taller, having more vigour and lower reaction to Striga parasitism which resulted in the crop producing higher dry matter compared to the other two varieties. The plots inoculated with Striga only supported shorter plants of sorghum varieties, higher vigour and lower reaction score to Striga compared to Striga mixed with Glomus. It is obvious in this study that the crop performance increases with increase in the rates of NPK fertilizer applied. PMID:24511701

  19. Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China.

    PubMed

    Wei, Yuan; Chen, Zhipeng; Wu, Fengchang; Hou, Hong; Li, Jining; Shangguan, Yuxian; Zhang, Juan; Li, Fasheng; Zeng, Qingru

    2015-03-01

    Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area. PMID:25766009

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

    PubMed

    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

  1. Revealing Natural Relationships among Arbuscular Mycorrhizal Fungi: Culture Line BEG47 Represents Diversispora epigaea, Not Glomus versiforme

    PubMed Central

    Schüßler, Arthur; Krüger, Manuela; Walker, Christopher

    2011-01-01

    Background Understanding the mechanisms underlying biological phenomena, such as evolutionarily conservative trait inheritance, is predicated on knowledge of the natural relationships among organisms. However, despite their enormous ecological significance, many of the ubiquitous soil inhabiting and plant symbiotic arbuscular mycorrhizal fungi (AMF, phylum Glomeromycota) are incorrectly classified. Methodology/Principal Findings Here, we focused on a frequently used model AMF registered as culture BEG47. This fungus is a descendent of the ex-type culture-lineage of Glomus epigaeum, which in 1983 was synonymised with Glomus versiforme. It has since then been used as ‘G. versiforme BEG47’. We show by morphological comparisons, based on type material, collected 1860–61, of G. versiforme and on type material and living ex-type cultures of G. epigaeum, that these two AMF species cannot be conspecific, and by molecular phylogenetics that BEG47 is a member of the genus Diversispora. Conclusions This study highlights that experimental works published during the last >25 years on an AMF named ‘G. versiforme’ or ‘BEG47’ refer to D. epigaea, a species that is actually evolutionarily separated by hundreds of millions of years from all members of the genera in the Glomerales and thus from most other commonly used AMF ‘laboratory strains’. Detailed redescriptions substantiate the renaming of G. epigaeum (BEG47) as D. epigaea, positioning it systematically in the order Diversisporales, thus enabling an evolutionary understanding of genetical, physiological, and ecological traits, relative to those of other AMF. Diversispora epigaea is widely cultured as a laboratory strain of AMF, whereas G. versiforme appears not to have been cultured nor found in the field since its original description. PMID:21853113

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

    PubMed

    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.

  3. The Interaction between Arbuscular Mycorrhizal Fungi and Endophytic Bacteria Enhances Plant Growth of Acacia gerrardii under Salt Stress.

    PubMed

    Hashem, Abeer; Abd Allah, Elsayed F; Alqarawi, Abdulaziz A; Al-Huqail, Asma A; Wirth, Stephan; Egamberdieva, Dilfuza

    2016-01-01

    Microbes living symbiotically in plant tissues mutually cooperate with each other by providing nutrients for proliferation of the partner organism and have a beneficial effect on plant growth. However, few studies thus far have examined the interactive effect of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) in hostile conditions and their potential to improve plant stress tolerance. In this study, we investigated how the synergistic interactions of endophytic bacteria and AMF affect plant growth, nodulation, nutrient acquisition and stress tolerance of Acacia gerrardii under salt stress. Plant growth varied between the treatments with both single inoculants and was higher in plants inoculated with the endophytic B. subtilis strain than with AMF. Co-inoculated A. gerrardii had a significantly greater shoot and root dry weight, nodule number, and leghemoglobin content than those inoculated with AMF or B. subtilis alone under salt stress. The endophytic B. subtilis could alleviate the adverse effect of salt on AMF colonization. The differences in nitrate and nitrite reductase and nitrogenase activities between uninoculated plants and those inoculated with AMF and B. subtilis together under stress were significant. Both inoculation treatments, either B. subtilis alone or combined with AMF, enhanced the N, P, K, Mg, and Ca contents and phosphatase activities in salt-stressed A. gerrardii tissues and reduced Na and Cl concentration, thereby protecting salt-stressed plants from ionic and osmotic stress-induced changes. In conclusion, our results indicate that endophytic bacteria and AMF contribute to a tripartite mutualistic symbiosis in A. gerrardii and are coordinately involved in the plant adaptation to salt stress tolerance. PMID:27486442

  4. Sporulation and diversity of arbuscular mycorrhizal fungi in Brazil Pine in the field and in the greenhouse.

    PubMed

    Moreira, Milene; Nogueira, Marco A; Tsai, Siu M; Gomes-da-Costa, Sandra M; Cardoso, Elke J B N

    2007-09-01

    The aim of this work was to assess the sporulation and diversity of arbuscular mycorrhizal fungi (AMF) at different forest sites with Araucaria angustifolia (Bert.) O. Ktze. (Brazil Pine). In addition, a greenhouse experiment was carried out to test the use of traditional trap plants (maize + peanut) or A. angustifolia to estimate the diversity of AMF at each site. Soil samples were taken in two State Parks at southwestern Brazil: Campos do Jordão (Parque Estadual de Campos do Jordão [PECJ]) and Apiaí (Parque Estadual Turístico do Alto Ribeira [PETAR]), São Paulo State, in sites of either native or replanted forest. In PECJ, an extra site of replanted forest that was impacted by accidental fire and is now in a state of recuperation was also sampled. The spore densities and their morphological identification were compiled at each site. In the greenhouse, soil samples from each site were used as inoculum to promote spore multiplication on maize + peanut or A. angustifolia grown on a sandy, low-fertility substrate. Plants were harvested, respectively, after 4 months or 1 year of growth and assessed for mycorrhizal root colonization. Spore counts and identification were also performed in the substrate, after the harvest of plants. Twenty-five taxa were identified considering all sites. Species richness and diversity were greater in native forest areas, being Acaulospora, the genus with the most species. Differences in number of spores, diversity, and richness were found at the different sites of each State Park. Differences were also found when maize + peanut or A. angustifolia were used as trap plants. The traditional methodology using trap plants seems to underestimate the diversity of the AMF. The use of A. angustifolia as trap plant showed similar species richness to the field in PECJ, but the identified species were not necessarily the same. Nevertheless, for PETAR, both A. angustifolia and maize + peanut underestimated the species richness. Because the AMF

  5. [Mycotrophic capacity and efficiency of microbial consortia of arbuscular mycorrhizal fungi native of soils from Buenos Aires province under contrasting management].

    PubMed

    Thougnon Islas, Andrea J; Eyherabide, Mercedes; Echeverría, Hernán E; Sainz Rozas, Hernán R; Covacevich, Fernanda

    2014-01-01

    We characterized the infective and sporulation capacities of microbial consortia of arbuscular mycorrhizal fungi (AMF) native of Buenos Aires province (Argentina) and determined if some soil characteristics and mycorrhizal parameters could allow to select potentially beneficial inocula. Soil samples were selected from seven locations in Buenos Aires province all under agricultural (A) and pristine (P) conditions. The AMF were multiplied and mycorrhizal root colonization of trap plants was observed at 10 weeks of growth. Spore number in field was low; however, after multiplication spore density accounted for 80-1175 spores per 100g of soil. The principal component analysis showed that the P and Fe soil contents are the main modulators of infectivity and sporulation capacity. The mycorrhizal potential was determined in three locations, being high in Pristine Lobería and Agricultural Trenque Lauquen and low in Junín. Agricultural Lobería (AL) and Pristine Lobería (PL) inocula were selected and their efficiency was evaluated under controlled conditions. Even though shoot dry matter increases after inoculation was not significant (p>0.05) mycorrhizal response was greater than 40% for tomato and 25% for corn, particularly after inoculation with inocula from the agricultural management. These results could be associated to the incipient development of mycorrhizae in both species. Additional research should be conducted to further develop our findings in order to determine the factors involved in the selection of efficient inocula. PMID:25011598

  6. Effectiveness of arbuscular mycorrhizal fungi (AMF) for inducing the accumulation of major carotenoids, chlorophylls and tocopherol in green and red leaf lettuces.

    PubMed

    Baslam, Marouane; Esteban, Raquel; García-Plazaola, José I; Goicoechea, Nieves

    2013-04-01

    Previous studies demonstrated that arbuscular mycorrhizal fungi (AMF) can induce the accumulation of carotenoids, phenolics, anthocyanins and some mineral nutrients in leaves of lettuce (Lactuca sativa L.) thus enhancing its nutritional quality. Our objectives were to know which carotenoids were the most accumulated in leaves of mycorrhizal lettuces and to assess the effect of AMF on tocopherols' levels in leaves of lettuce plants. AMF always enhanced growth and, in most cases, increased the levels of all major carotenoids, chlorophylls and tocopherols in green and red leaf lettuces. Since these molecules are also important nutraceuticals, mycorrhization emerges as reliable technique to enhance the nutritional value of edible vegetables. These results are compared with other methods developed to improve nutritional quality.

  7. Hormonal and transcriptional profiles highlight common and differential host responses to arbuscular mycorrhizal fungi and the regulation of the oxylipin pathway

    PubMed Central

    López-Ráez, Juan A.; Verhage, Adriaan; Fernández, Iván; García, Juan M.; Azcón-Aguilar, Concepción; Flors, Victor; Pozo, María J.

    2010-01-01

    Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. The symbiosis significantly affects the host physiology in terms of nutrition and stress resistance. Despite the lack of host range specificity of the interaction, functional diversity between AM fungal species exists. The interaction is finely regulated according to plant and fungal characters, and plant hormones are believed to orchestrate the modifications in the host plant. Using tomato as a model, an integrative analysis of the host response to different mycorrhizal fungi was performed combining multiple hormone determination and transcriptional profiling. Analysis of ethylene-, abscisic acid-, salicylic acid-, and jasmonate-related compounds evidenced common and divergent responses of tomato roots to Glomus mosseae and Glomus intraradices, two fungi differing in their colonization abilities and impact on the host. Both hormonal and transcriptional analyses revealed, among others, regulation of the oxylipin pathway during the AM symbiosis and point to a key regulatory role for jasmonates. In addition, the results suggest that specific responses to particular fungi underlie the differential impact of individual AM fungi on plant physiology, and particularly on its ability to cope with biotic stresses. PMID:20378666

  8. OCCURRENCE OF ARBUSCULAR MYCORRHIZAL FUNGI IN SOME MEDICINAL PLANTS OF KERALA

    PubMed Central

    Mathew, Abraham; Malathy, M.R.

    2006-01-01

    The occurrence of mycorrhiza in 40 selected medicinal plants was studied. The percentage of mycorrhizal colonization in each of the plant was calculated. The colonization was found to be very less in four plants and very high in six plants. All others showed a moderate level of colonization. The present work suggests the use of mycorrhiza as a biofertilizer to enhance the growth and yield of medicinal plants. PMID:22557224

  9. Improvement of growth of Eucalyptus globulus and soil biological parameters by amendment with sewage sludge and inoculation with arbuscular mycorrhizal and saprobe fungi.

    PubMed

    Arriagada, C; Sampedro, I; Garcia-Romera, I; Ocampo, J

    2009-08-15

    Sewage sludge is widely used as an organic soil amendment to improve soil fertility. We investigated the effects of sewage sludge (SS) application on certain biological parameters of Eucalyptus globulus Labill. The plant was either uninoculated or inoculated with saprobe fungi (Coriolopsis rigida and Trichoderma harzianum) or arbuscular mycorrhizal (AM) fungi (Glomus deserticola and Gigaspora rosea). Sewage sludge was applied to the surface of experimental plots at rates of 0, 2, 4, 6 and 8 g 100 g(-1) of soil. Inoculation with both AM and saprobe fungi in the presence of SS was essential for the promotion of plant growth. The AM, saprobe fungi and SS significantly increased dry shoot weight. The AM fungi induced a significant increase in Fluorescein diacetate (FDA) activity but did not increase beta-glucosidase activity. Addition of SS to AM-inoculated soil did not affect either FDA or alpha-glucosidase activities in plants from soil that was either uninoculated or inoculated with the saprobe fungi. SS increased beta-glucosidase activity when it was applied at 4 g 100 g(-1). SS negatively affected AM colonization as well as the mycelium SDH activity for both mycorrhizal fungi. SS increased Eucalyptus shoot biomass and enhanced its nutrient status. Inoculation of the soil with G. deserticola stimulated significant E. globulus growth and increases in shoot tissue content of N, P, K, Ca, Mg and Fe. Dual inoculation with G. deserticola and either of the saprobe fungi had positive effects on K, Ca, Mg and Fe contents. The application of 8 g 100 g(-1) of SS had no positive effects on plant nutrition. The experimental setup provided a suitable tool for evaluating SS in combination with saprobe and AM fungi as a biological fertiliser for its beneficial effects on E. globulus plant growth. PMID:19515400

  10. Improvement of growth of Eucalyptus globulus and soil biological parameters by amendment with sewage sludge and inoculation with arbuscular mycorrhizal and saprobe fungi.

    PubMed

    Arriagada, C; Sampedro, I; Garcia-Romera, I; Ocampo, J

    2009-08-15

    Sewage sludge is widely used as an organic soil amendment to improve soil fertility. We investigated the effects of sewage sludge (SS) application on certain biological parameters of Eucalyptus globulus Labill. The plant was either uninoculated or inoculated with saprobe fungi (Coriolopsis rigida and Trichoderma harzianum) or arbuscular mycorrhizal (AM) fungi (Glomus deserticola and Gigaspora rosea). Sewage sludge was applied to the surface of experimental plots at rates of 0, 2, 4, 6 and 8 g 100 g(-1) of soil. Inoculation with both AM and saprobe fungi in the presence of SS was essential for the promotion of plant growth. The AM, saprobe fungi and SS significantly increased dry shoot weight. The AM fungi induced a significant increase in Fluorescein diacetate (FDA) activity but did not increase beta-glucosidase activity. Addition of SS to AM-inoculated soil did not affect either FDA or alpha-glucosidase activities in plants from soil that was either uninoculated or inoculated with the saprobe fungi. SS increased beta-glucosidase activity when it was applied at 4 g 100 g(-1). SS negatively affected AM colonization as well as the mycelium SDH activity for both mycorrhizal fungi. SS increased Eucalyptus shoot biomass and enhanced its nutrient status. Inoculation of the soil with G. deserticola stimulated significant E. globulus growth and increases in shoot tissue content of N, P, K, Ca, Mg and Fe. Dual inoculation with G. deserticola and either of the saprobe fungi had positive effects on K, Ca, Mg and Fe contents. The application of 8 g 100 g(-1) of SS had no positive effects on plant nutrition. The experimental setup provided a suitable tool for evaluating SS in combination with saprobe and AM fungi as a biological fertiliser for its beneficial effects on E. globulus plant growth.

  11. Protozoa enhance foraging efficiency of arbuscular mycorrhizal fungi for mineral nitrogen from organic matter in soil to the benefit of host plants.

    PubMed

    Koller, Robert; Rodriguez, Alia; Robin, Christophe; Scheu, Stefan; Bonkowski, Michael

    2013-07-01

    Dead organic matter (OM) is a major source of nitrogen (N) for plants. The majority of plants support N uptake by symbiosis with arbuscular mycorrhizal (AM) fungi. Mineralization of N is regulated by microfauna, in particular, protozoa grazing on bacteria. We hypothesized that AM fungi and protozoa interactively facilitate plant N nutrition from OM. In soil systems consisting of an OM patch and a root compartment, plant N uptake and consequences for plant carbon (C) allocation were investigated using stable isotopes. Protozoa mobilized N by consuming bacteria, and the mobilized N was translocated via AM fungi to the host plant. The presence of protozoa in both the OM and root compartment stimulated photosynthesis and the translocation of C from the host plant via AM fungi into the OM patch. This stimulated microbial activity in the OM patch, plant N uptake from OM and doubled plant growth. The results indicate that protozoa increase plant growth by both mobilization of N from OM and by protozoa-root interactions, resulting in increased C allocation to roots and into the rhizosphere, thereby increasing plant nutrient exploitation. Hence, mycorrhizal plants need to interact with protozoa to fully exploit N resources from OM.

  12. Protozoa enhance foraging efficiency of arbuscular mycorrhizal fungi for mineral nitrogen from organic matter in soil to the benefit of host plants.

    PubMed

    Koller, Robert; Rodriguez, Alia; Robin, Christophe; Scheu, Stefan; Bonkowski, Michael

    2013-07-01

    Dead organic matter (OM) is a major source of nitrogen (N) for plants. The majority of plants support N uptake by symbiosis with arbuscular mycorrhizal (AM) fungi. Mineralization of N is regulated by microfauna, in particular, protozoa grazing on bacteria. We hypothesized that AM fungi and protozoa interactively facilitate plant N nutrition from OM. In soil systems consisting of an OM patch and a root compartment, plant N uptake and consequences for plant carbon (C) allocation were investigated using stable isotopes. Protozoa mobilized N by consuming bacteria, and the mobilized N was translocated via AM fungi to the host plant. The presence of protozoa in both the OM and root compartment stimulated photosynthesis and the translocation of C from the host plant via AM fungi into the OM patch. This stimulated microbial activity in the OM patch, plant N uptake from OM and doubled plant growth. The results indicate that protozoa increase plant growth by both mobilization of N from OM and by protozoa-root interactions, resulting in increased C allocation to roots and into the rhizosphere, thereby increasing plant nutrient exploitation. Hence, mycorrhizal plants need to interact with protozoa to fully exploit N resources from OM. PMID:23534902

  13. Recent developments in arbuscular mycorrhizal signaling.

    PubMed

    Gobbato, Enrico

    2015-08-01

    Plants can establish root endosymbioses with both arbuscular mycorrhizal fungi and rhizobial bacteria to improve their nutrition. Our understanding of the molecular events underlying the establishment of these symbioses has significantly advanced in the last few years. Here I highlight major recent findings in the field of endosymbiosis signaling. Despite the identification of new signaling components and the definition, or in some cases better re-definition of the molecular functions of previously known players, major questions still remain that need to be addressed. Most notably the mechanisms defining signaling specificities within either symbiosis remain unclear. PMID:26043435

  14. Effect of arbuscular mycorrhizal fungi on growth and on micronutrient and macronutrient uptake and allocation in olive plantlets growing under high total Mn levels.

    PubMed

    Briccoli Bati, Caterina; Santilli, Elena; Lombardo, Luca

    2015-02-01

    The reported work was designed to increase knowledge about the role of arbuscular mycorrhizal fungi (AMF) on the phytoavailability and allocation of some of the principal macroelements and microelements in young potted olive plants growing in a soil presenting high levels of manganese (Mn), taken from an experimental olive field. A greenhouse trial was performed using self-rooted cuttings of Ascolana tenera, Nocellara del Belice and Carolea cultivars inoculated or not with two mycorrhizal inocula (commercial vs native). Molecular characterization of the indigenous AMF indicated that the species found in the experimental soil were different from those present in the commercial inoculum. The important incidence of AMF on P uptake was confirmed with generally double the concentration in mycorrhizal olive plants as compared to non-mycorrhizal controls, irrespective of genotype and inocula. Furthermore, apart from promoting plant growth (from 1.7- to 5-fold), the symbiosis reduced Mn concentrations from 43 to 83%. The observed differences depended on the cultivar and the inoculum, with native AMF being more effective probably as a result of their adaptation to the experimental soil. No clear direct relationship was found between AMF inoculation and other elements analysed.

  15. Effect of Arbuscular Mycorrhizal Fungi On Yield and Phytoremediation Performance of Pot Marigold (Calendula officinalis L.) Under Heavy Metals Stress.

    PubMed

    Tabrizi, Leila; Mohammadi, Siavash; Delshad, Mojtaba; Moteshare Zadeh, Babak

    2015-01-01

    In order to study the effect of mycorrhizal fungi (inoculated and non-inoculated) and heavy metals stress [0, Pb (150 and 300 mg/kg) and Cd (40 and 80 mg/kg)] on pot marigold (Calendula officinalis L.), a factorial experiment was conducted based on a randomized complete block design with 4 replications in Research Greenhouse of Department of Horticultural Sciences, University of Tehran, Iran, during 2012-2013. Plant height, herbal and flower fresh and dry weight, root fresh and dry weight and root volume, colonization percentage, total petal extract, total petal flavonoids, root and shoot P and K uptakes, and Pb and Cd accumulations in root and shoot were measured. Results indicated that with increasing soil Pb and Cd concentration, growth and yield of pot marigold was reduced significantly; Cd had greater negative impacts than Pb. However, mycorrhizal fungi alleviated these impacts by improving plant growth and yield. Pot marigold concentrated high amounts of Pb and especially Cd in its roots and shoots; mycorrhizal plants had a greater accumulation of these metals, so that those under 80 mg/kg Cd soil(-1) accumulated 833.3 and 1585.8 mg Cd in their shoots and roots, respectively. In conclusion, mycorrhizal fungi can improve not only growth and yield of pot marigold in heavy metal stressed condition, but also phytoremediation performance by increasing heavy metals accumulation in the plant organs. PMID:26237494

  16. Effect of Arbuscular Mycorrhizal Fungi On Yield and Phytoremediation Performance of Pot Marigold (Calendula officinalis L.) Under Heavy Metals Stress.

    PubMed

    Tabrizi, Leila; Mohammadi, Siavash; Delshad, Mojtaba; Moteshare Zadeh, Babak

    2015-01-01

    In order to study the effect of mycorrhizal fungi (inoculated and non-inoculated) and heavy metals stress [0, Pb (150 and 300 mg/kg) and Cd (40 and 80 mg/kg)] on pot marigold (Calendula officinalis L.), a factorial experiment was conducted based on a randomized complete block design with 4 replications in Research Greenhouse of Department of Horticultural Sciences, University of Tehran, Iran, during 2012-2013. Plant height, herbal and flower fresh and dry weight, root fresh and dry weight and root volume, colonization percentage, total petal extract, total petal flavonoids, root and shoot P and K uptakes, and Pb and Cd accumulations in root and shoot were measured. Results indicated that with increasing soil Pb and Cd concentration, growth and yield of pot marigold was reduced significantly; Cd had greater negative impacts than Pb. However, mycorrhizal fungi alleviated these impacts by improving plant growth and yield. Pot marigold concentrated high amounts of Pb and especially Cd in its roots and shoots; mycorrhizal plants had a greater accumulation of these metals, so that those under 80 mg/kg Cd soil(-1) accumulated 833.3 and 1585.8 mg Cd in their shoots and roots, respectively. In conclusion, mycorrhizal fungi can improve not only growth and yield of pot marigold in heavy metal stressed condition, but also phytoremediation performance by increasing heavy metals accumulation in the plant organs.

  17. Mycotrophy of crops in rotation and soil amendment with peat influence the abundance and effectiveness of indigenous arbuscular mycorrhizal fungi in field soil.

    PubMed

    Vestberg, M; Saari, K; Kukkonen, S; Hurme, T

    2005-09-01

    Mycotrophy of previous crops has been shown to have an impact on arbuscular mycorrhizal fungi (AMF), and the growth and productivity of succeeding crops. We studied the impact of 3 years of cultivation of eight crops with different degrees of mycotrophy, including mycorrhizal (strawberry, rye, timothy, onion, caraway) and non-mycorrhizal (turnip rape, buckwheat, fiddleneck) hosts, as well as the impact of peat amendment, on the effectiveness, amount and diversity of indigenous AMF. A field experiment having a split-plot design with peat amendment as the main plot, crop cultivation as a sub-plot and three replications, was carried out on silt clay mineral soil in 1999-2001. A well-humified dark peat was applied immediately before establishment of the field experiment. Each year, the relative mycorrhizal effectiveness of soil collected in September, in terms of shoot dry weight (RME(DW)), was determined in a bioassay. In the 3rd year of the experiment, AMF spores were also extracted and identified from the field soil. Expressed as the mean of 3 years of cropping in unamended soil, the mycorrhizal crops strawberry and caraway maintained RME(DW) most effectively, while the values were lower in the non-host crops buckwheat, turnip rape and fiddleneck. In addition, the numbers of AM spores detected in soil were considerably greater during 3 years of strawberry cultivation. In soil under caraway, there were high numbers of AM spores compared to the other crops. In soil amended with peat, the situation was in some cases opposite of that of unamended soil; RME(DW) was highest in rye and onion and lowest in strawberry and caraway. The reasons behind the negative impact of peat on mycorrhizal effectiveness in strawberry soil may be due to the microbiological properties of peat. The importance of including mycotrophic species in crop rotations for maintaining high soil quality and for increasing yields of subsequent crops is discussed.

  18. Colonization of arbuscular-mycorrhizal fungi on Ri T-DNA transformed roots in synthetic medium.

    PubMed

    Abdul-Khaliq; Bagyaraj, D J

    2000-11-01

    Hairy root culture of tomato (Lycopersicon esculantum L.) was induced with three strains of Agrobacterium rhizogenes namely A4, ATCC 15834 and LBA 9402. The best response in terms of growth of hairy root was observed with A. rhizogenes strain A4 and LBA 9402 followed by ATCC 15834. Hairy roots were maintained on Murashige and Skoog (MS) medium but it could also grow on minimal (M) medium. Spores of Gigaspora margarita were isolated by wet sieving and decanting method and further recovered by sucrose density gradient method. A new method for surface sterilization of spores has been described which is simpler than the methods described earlier. Surface sterilized spores of G. margarita were used for inoculation of transformed roots grown on M medium as it was found more favourable for germination and growth of spores. During co-cultivation, mycorrhizal spore germination and its penetration into root cortex were observed. Inter and intracellular mycelial spread and formation of arbuscules were also observed in the cortical region of transformed roots of this plant.

  19. Preservation at ultra-low temperature of in vitro cultured arbuscular mycorrhizal fungi via encapsulation-drying.

    PubMed

    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. 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.

    PubMed

    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.

  1. Response of Sesbania grandiflora to Inoculation of Soil with Vesicular-Arbuscular Mycorrhizal Fungi.

    PubMed

    Habte, M; Aziz, T

    1985-09-01

    A greenhouse experiment was conducted to determine the influence of two tropical isolates of Glomus fasciculatum and Glomus mosseae on the nutrient uptake and growth of Sesbania grandiflora. Inoculation of sterile soil with the fungi significantly improved growth and nutrient uptake by S. grandiflora, but the response of the legume was markedly better when the soil was inoculated with G. fasciculatum than when it was inoculated with G. mosseae. Nutrient uptake and growth of S. grandiflora in nonsterile soil was also significantly stimulated by inoculation, but the legume did not respond differently to the two endophytes under this condition. PMID:16346890

  2. Response of Sesbania grandiflora to Inoculation of Soil with Vesicular-Arbuscular Mycorrhizal Fungi

    PubMed Central

    Habte, Mitiku; Aziz, Taufiqul

    1985-01-01

    A greenhouse experiment was conducted to determine the influence of two tropical isolates of Glomus fasciculatum and Glomus mosseae on the nutrient uptake and growth of Sesbania grandiflora. Inoculation of sterile soil with the fungi significantly improved growth and nutrient uptake by S. grandiflora, but the response of the legume was markedly better when the soil was inoculated with G. fasciculatum than when it was inoculated with G. mosseae. Nutrient uptake and growth of S. grandiflora in nonsterile soil was also significantly stimulated by inoculation, but the legume did not respond differently to the two endophytes under this condition. PMID:16346890

  3. [Effects of arbuscular mycorrhizal fungi on the growth and rare earth elements uptake of soybean grown in rare earth mine tailings].

    PubMed

    Guo, Wei; Zhao, Ren-xin; Zhao, Wen-jing; Fu, Rui-ying; Guo, Jiang-yuan; Zhang, Jun

    2013-05-01

    A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus versiforme on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals and rare earth elements by soybean (Glycine max) grown in rare earth mine tailings. The aim was to provide a basis for the revegetation of rare earth mine tailings. The results indicated that soybean had a high mycorrhizal colonization and symbiotic associations were successfully established with G. versiforme, with an average rate of approximately 67%. The colonization of G. versiforme significantly promoted the growth of soybean, increased P, K contents, and decreased C: N: P ratios, supporting the growth rate hypothesis. Inoculation with G. versiforme significantly decreased shoots and roots La, Ce, Pr and Nd concentrations of soybean compared to the control treatment. However, inoculation with G. versiforme had no significant effect on the heavy metal concentrations, except for significantly decreased shoot Fe and Cr concentrations and increased root Cd concentrations. The experiment demonstrates that AM fungi have a potential role for soybean to adapt the composite adversity of rare earth tailings and play a positive role in revegetation of rare earth mine tailings. Further studies on the role of AM fungi under natural conditions should be conducted.

  4. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

    PubMed

    Yang, Yurong; Han, Xiaozhen; Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg(-1) soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb

  5. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

    DOE PAGES

    Yang, Yurong; Han, Xiaozhen; Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

    2015-12-23

    Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation ofmore » biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. In conclusion, our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization

  6. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

    PubMed

    Yang, Yurong; Han, Xiaozhen; Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg(-1) soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb

  7. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

    SciTech Connect

    Yang, Yurong; Han, Xiaozhen; Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

    2015-12-23

    Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. In conclusion, our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the

  8. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

    PubMed Central

    Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated

  9. Extraradical mycelium of arbuscular mycorrhizal fungi radiating from large plants depresses the growth of nearby seedlings in a nutrient deficient substrate.

    PubMed

    Janoušková, Martina; Rydlová, Jana; Püschel, David; Száková, Jiřina; Vosátka, Miroslav

    2011-10-01

    The effect of arbuscular mycorrhiza (AM) on the interaction of large plants and seedlings in an early succession situation was investigated in a greenhouse experiment using compartmented rhizoboxes. Tripleurospermum inodorum, a highly mycorrhiza-responsive early coloniser of spoil banks, was cultivated either non-mycorrhizal or inoculated with AM fungi in the central compartment of the rhizoboxes. After two months, seedlings of T. inodorum or Sisymbrium loeselii, a non-host species colonising spoil banks simultaneously with T. inodorum, were planted in lateral compartments, which were colonised by the extraradical mycelium (ERM) of the pre-cultivated T. inodorum in the inoculated treatments. The experiment comprised the comparison of two AM fungal isolates and two substrates: spoil bank soil and a mixture of this soil with sand. As expected based on the low nutrient levels in the substrates, the pre-cultivated T. inodorum plants responded positively to mycorrhiza, the response being more pronounced in phosphorus uptake than in nitrogen uptake and growth. In contrast, the growth of the seedlings, both the host and the non-host species, was inhibited in the mycorrhizal treatments. Based on the phosphorus and nitrogen concentrations in the biomass of the experimental plants, this growth inhibition was attributed to nitrogen depletion in the lateral compartments by the ERM radiating from the central compartment. The results point to an important aspect of mycorrhizal effects on the coexistence of large plants and seedlings in nutrient deficient substrates.

  10. Occurrence of arbuscular mycorrhizal fungi in saline soils of the Tabriz Plain of Iran in relation to some physical and chemical properties of soil.

    PubMed

    Aliasgharzadeh, N; Rastin, S N; Towfighi, H; Alizadeh, A

    2001-08-01

    The abundance and distribution of arbuscular mycorrhizal fungi (AMF) were evaluated in the Tabriz Plain, where soil salinity levels range from 7.3 to 92.0 dS/m. Soil and root samples were collected from the rhizosphere of several glycophytes (Allium cepa L., Medicago sativa L., Triticum aestivum L. and Hordeum vulgare L.) and halophytes (Salicornia sp. and Salsola sp.) and were analysed for spore number in soil, root colonization with AMF and some physical and chemical soil properties. The number of AMF spores was not correlated significantly with soil salinity but suffered adverse effects from the accumulation of some anions and cations. Cluster analysis of correlation matrices showed that root colonization, soil pH, sand and clay percent, and soil-available P, rather than soil salinity and ion concentrations, were closely related with spore number. The percentage of root length colonized in glycophytes significantly decreased with increasing soil salinity. Barley roots showed 5% mycorrhizal colonization in high soil salinity (~20 dS/m). Halophyte roots were not mycorrhizal but more spores were found in rhizosphere than in non-rhizosphere soil. PMID:24595430

  11. The potential role of arbuscular mycorrhizal (AM) fungi in the bioprotection of plants against soil-borne pathogens in organic and/or other sustainable farming systems.

    PubMed

    Harrier, Lucy A; Watson, Christine A

    2004-02-01

    Sustainable farming systems strive to minimise the use of synthetic pesticides and to optimise the use of alternative management strategies to control soil-borne pathogens. Arbuscular mycorrhizal (AM) fungi are ubiquitous in nature and constitute an integral component of terrestrial ecosystems, forming symbiotic associations with plant root systems of over 80% of all terrestrial plant species, including many agronomically important species. AM fungi are particularly important in organic and/or sustainable farming systems that rely on biological processes rather than agrochemicals to control plant diseases. Of particular importance is the bioprotection conferred to plants against many soil-borne pathogens such as species of Aphanomyces, Cylindrocladium, Fusarium, Macrophomina, Phytophthora, Pythium, Rhizoctonia, Sclerotinium, Verticillium and Thielaviopsis and various nematodes by AM fungal colonisation of the plant root. However, the exact mechanisms by which AM fungal colonisation confers the protective effect are not completely understood, but a greater understanding of these beneficial interactions is necessary for the exploitation of AM fungi within organic and/or sustainable farming systems. In this review, we aim to discuss the potential mechanisms by which AM fungi may contribute to bioprotection against plant soil-borne pathogens. Bioprotection within AM fungal-colonised plants is the outcome of complex interactions between plants, pathogens and AM fungi. The use of molecular tools in the study of these multifaceted interactions may aid the optimisation of the bioprotective responses and their utility within sustainable farming systems.

  12. The diversity of arbuscular mycorrhizal fungi amplified from grapevine roots (Vitis vinifera L.) in Oregon vineyards is seasonally stable and influenced by soil and vine age.

    PubMed

    Schreiner, R Paul; Mihara, Keiko L

    2009-01-01

    The diversity of arbuscular mycorrhizal fungi (AMF) in 10 Oregon vineyards was assessed by examining spores in soil and amplifying mycorrhizal DNA from roots. Seventeen spore morphotypes were found in soil, including seven species in the Acaulosporaceae. Eighteen phylotypes were amplified from grape roots with AM1 and NS31 primers, and clones were dominated by Glomus spp. (> 99%). A few clones (< 1%) representing a single phylotype within Gigasporaceae, and a single clone within Archaeosporaceae were amplified from roots with AM1-NS31 primers. A separate experiment employing known proportions of grape roots colonized by Glomus intraradices or by Gigaspora rosea showed that fungi within Gigasporaceae might be underrepresented in clone abundance when Glomus spp. co-occur in roots. No clones representing fungi within the Acaulosporaceae were amplified from vineyards, although specific fungi within Acaulosporaceae were shown to colonize Pinot noir roots in sterilized soil and were amplified from these roots. Four Glomus phylotypes, including G. intraradices, were found in roots from all 10 vineyards, and these fungi accounted for 81% of clones. AMF phylotypes amplified from roots did not change during the growing season, although six phylotypes varied with soil type. The presence of three phylotypes was affected by vineyard age, and phylotype richness appeared to decline as vineyard age increased beyond 20 y. PCA analysis supported the hypothesis that the AMF community is different in red-hill soils than in valley soils and indicated certain phylotypes might be associated with lower soil and vine nutrient status. However, the changes in the AMF community in grape roots across vineyards were subtle because most root samples were dominated by the same three or four phylotypes. A separate analysis using primers to amplify AMF from the Archeasporaceae/Paraglomeraceae showed most root samples also were colonized by at least one Paraglomus or Archaeospora phylotype.

  13. Remediation of polychlorinated biphenyl-contaminated soil by using a combination of ryegrass, arbuscular mycorrhizal fungi and earthworms.

    PubMed

    Lu, Yan-Fei; Lu, Mang; Peng, Fang; Wan, Yun; Liao, Min-Hong

    2014-07-01

    In this work, a laboratory experiment was performed to investigate the influences of inoculation with the arbuscular mycorrhizal fungus (AMF) Glomus caledoniun L. and/or epigeic earthworms (Eisenia foetida) on phytoremediation of a PCB-contaminated soil by ryegrass grown for 180d. Planting ryegrass, ryegrass inoculated with earthworms, ryegrass inoculated with AMF, and ryegrass co-inoculated with AMF and earthworms decreased significantly initial soil PCB contents by 58.4%, 62.6%, 74.3%, and 79.5%, respectively. Inoculation with AMF and/or earthworms increased the yield of plants, and the accumulation of PCBs in ryegrass. However, PCB uptake by ryegrass accounted for a negligible portion of soil PCB removal. The number of soil PCB-degrading populations increased when ryegrass was inoculated with AMF and/or earthworms. The data show that fungal inoculation may significantly increase the remedial potential of ryegrass for soil contaminated with PCBs.

  14. Haustorium Formation in Medicago truncatula Roots Infected by Phytophthora palmivora Does Not Involve the Common Endosymbiotic Program Shared by Arbuscular Mycorrhizal Fungi and Rhizobia.

    PubMed

    Huisman, Rik; Bouwmeester, Klaas; Brattinga, Marijke; Govers, Francine; Bisseling, Ton; Limpens, Erik

    2015-12-01

    In biotrophic plant-microbe interactions, microbes infect living plant cells, in which they are hosted in a novel membrane compartment, the host-microbe interface. To create a host-microbe interface, arbuscular mycorrhizal (AM) fungi and rhizobia make use of the same endosymbiotic program. It is a long-standing hypothesis that pathogens make use of plant proteins that are dedicated to mutualistic symbiosis to infect plants and form haustoria. In this report, we developed a Phytophthora palmivora pathosystem to study haustorium formation in Medicago truncatula roots. We show that P. palmivora does not require host genes that are essential for symbiotic infection and host-microbe interface formation to infect Medicago roots and form haustoria. Based on these findings, we conclude that P. palmivora does not hijack the ancient intracellular accommodation program used by symbiotic microbes to form a biotrophic host-microbe interface.

  15. Ascorbate oxidase: the unexpected involvement of a 'wasteful enzyme' in the symbioses with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi.

    PubMed

    Balestrini, Raffaella; Ott, Thomas; Güther, Mike; Bonfante, Paola; Udvardi, Michael K; De Tullio, Mario C

    2012-10-01

    Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO over-expressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that the expression of a Lotus japonicus AO gene is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi. In this framework, high AO expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of AM symbiosis. A general model of AO function in plants is discussed.

  16. Enhancing growth performance and systemic acquired resistance of medicinal plant Sesbania sesban (L.) Merr using arbuscular mycorrhizal fungi under salt stress

    PubMed Central

    Abd_Allah, Elsayed Fathi; Hashem, Abeer; Alqarawi, Abdulaziz Abdullah; Bahkali, Ali Hassan; Alwhibi, Mona S.

    2015-01-01

    Pot experiments were conducted to evaluate the damaging effects of salinity on Sesbania sesban plants in the presence and absence of arbuscular mycorrhizal fungi (AMF). The selected morphological, physiological and biochemical parameters of S. sesban were measured. Salinity reduced growth and chlorophyll content drastically while as AMF inoculated plants improved growth. A decrease in the number of nodules, nodule weight and nitrogenase activity was also evident due to salinity stress causing reduction in nitrogen fixation and assimilation potential. AMF inoculation increased these parameters and also ameliorated the salinity stress to some extent. Antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) as well as non enzymatic antioxidants (ascorbic acid and glutathione) also exhibited great variation with salinity treatment. Salinity caused great alterations in the endogenous levels of growth hormones with abscisic acid showing increment. AMF inoculated plants maintained higher levels of growth hormones and also allayed the negative impact of salinity. PMID:25972748

  17. Phosphorus and Nitrogen Regulate Arbuscular Mycorrhizal Symbiosis in Petunia hybrida

    PubMed Central

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

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi. PMID:24608923

  18. Phosphorus-32 absorption and translocation to host plants by arbuscular mycorrhizal fungi at low root-zone temperature.

    PubMed

    Wang, B; Funakoshi, D M; Dalpé, Y; Hamel, C

    2002-04-01

    Arbuscular mycorrhizal (AM) mycelia persist in soil over winter. Functioning of the AM symbiosis very early in the spring when the soil temperature is low may be of ecological significance for perennial and biannual plants in cool climates. An indoor experiment was conducted to investigate the effects of low root-zone temperatures on 32P uptake by 10-week-old leek plants (Allium porrum L.) inoculated or not with the AM fungus Glomus intraradices Schenck & Smith. Plants were grown in a greenhouse at approximately 23 degrees C prior to exposing their roots to 23 degrees C, 15 degrees C or 0 degree C. Mycorrhizal colonization increased 32P activity of leek leaves at a root-zone temperature of 23 degrees C seven days after injection of 32P into the soil, whereas 14 days after injection, 32P increases were measured at both 23 degrees C and 15 degrees C. The lack of difference in 32P activity between AM and non-AM plants at 0 degree C, both 7 and 14 days after injection, suggests that the AM fungus is not functional at this low root-zone temperature. PMID:12035733

  19. Temporal dynamics of arbuscular mycorrhizal fungi colonizing roots of representative shrub species in a semi-arid Mediterranean ecosystem.

    PubMed

    Sánchez-Castro, Iván; Ferrol, Nuria; Cornejo, Pablo; Barea, José-Miguel

    2012-08-01

    Arbuscular mycorrhizal (AM) symbiosis plays an important role in improving plant fitness and soil quality, particularly in fragile and stressed environments, as those in certain areas of Mediterranean ecosystems. AM fungal communities are usually affected by dynamic factors such as the plant community structure and composition, which in turn are imposed by seasonality. For this reason, a one-year-round time-course trial was performed by sampling the root system of two representative shrubland species (Rosmarinus officinalis and Thymus zygis) within a typical Mediterranean ecosystem from the Southeast of Spain. The 18S rDNA gene, of the AM fungal community in roots, was subjected to PCR-SSCP, sequencing, and phylogenetic analysis. Forty-three different AM fungal sequence types were found which clustered in 16 phylotypes: 14 belonged to the Glomeraceae and two to the Diversisporaceae. Surprisingly, only two of these phylotypes were related with sequences of morphologically defined species: Glomus intraradices and Glomus constrictum. Significant differences were detected for the relative abundance of some phylotypes while no effects were found for the calculated diversity indices. These results may help to design efficient mycorrhizal-based revegetation programs for this type of ecosystems. PMID:22124663

  20. Systemic and local regulation of phosphate and nitrogen transporter genes by arbuscular mycorrhizal fungi in roots of winter wheat (Triticum aestivum L.).

    PubMed

    Duan, Jianfeng; Tian, Hui; Drijber, Rhae A; Gao, Yajun

    2015-11-01

    Previous studies have reported that the expression of phosphate (Pi) or nitrogen (N) transporter genes in roots of plants could be regulated by arbuscular mycorrhizal (AM) fungi, but little is known whether the regulation is systemic or not. The present study investigated the systemic and local regulation of multiple phosphate and nitrogen transporter genes by four AM fungal species belonging to four genera in the roots of winter wheat. A split-root culture system with AM inoculated (MR) and non-inoculated root compartments (NR) was used to investigate the systemic or local responses of phosphate and nitrogen transporter genes to colonization by four AM fungi in the roots of wheat. The expression of four Pi transporter, five nitrate transporter, and three ammonium transporter genes was quantified using real-time PCR. Of the four AM fungi tested, all locally increased expression of the AM-inducible Pi transporter genes, and most locally decreased expression of a Pi-starvation inducible Pi transporter gene. The addition of N in soil increased the expression of either Pi starvation inducible Pi transporters or AM inducible Pi transporters. Inoculation with AM fungi either had no effect, or could locally or systemically down-regulate expression of nitrogen transporter genes depending on gene type and AM fungal species.

  1. Beneficial effect of saprobe and arbuscular mycorrhizal fungi on growth of Eucalyptus globulus co-cultured with Glycine max in soil contaminated with heavy metals.

    PubMed

    Arriagada, Cesar A; Herrera, Miguel A; Ocampo, Juan A

    2007-07-01

    The effects of saprobe and arbuscular mycorrhizal (AM) fungi on growth, chlorophyll and N, P and K content of Eucalyptus globulus Labill. growing in soil contaminated by heavy metals in the presence or absence of Glycine max were investigated. Glomus mosseae and Glomus deserticola increased dry weight, shoot length, total N, P and K concentration and the quantity of chlorophyll in E. globulus shoots. The protection of Eucalyptus by AM fungi against the action of the heavy metals was more evident when this plant grew as an intercrop with soybean than as a monoculture. The presence of the saprobe fungi Fusarium concolor and Trichoderma koningii further enhanced shoot dry weight, N, P and K content of AM Eucalyptus. The co-inoculation of Eucalyptus with Glomus deserticola and T. koningii was more effective for Cd uptake. In addition, Glomus deserticola enhanced the amount of Pb absorbed by Eucalyptus plants. We showed that it is important to select the most efficient AM and saprobe fungi to stimulate plant growth in heavy-metal-contaminated soil and that the combination of both plays an important role in metal tolerance of Eucalyptus plants.

  2. Effectiveness of native and exotic arbuscular mycorrhizal fungi on nutrient uptake and ion homeostasis in salt-stressed Cajanus cajan L. (Millsp.) genotypes.

    PubMed

    Garg, Neera; Pandey, Rekha

    2015-04-01

    Soil salinity is an increasing problem worldwide, restricting plant growth and production. Research findings show that arbuscular mycorrhizal (AM) fungi have the potential to reduce negative effects of salinity. However, plant growth responses to AM fungi vary as a result of genetic variation in mycorrhizal colonization and plant growth responsiveness. Thus, profitable use of AM requires selection of a suitable combination of host plant and fungal partner. A greenhouse experiment was conducted to compare effectiveness of a native AM fungal inoculum sourced from saline soil and two single exotic isolates, Funneliformis mossseae and Rhizophagus irregularis (single or dual mix), on Cajanus cajan (L.) Millsp. genotypes (Paras and Pusa 2002) under salt stress (0-100 mM NaCl). While salinity reduced plant biomass and disturbed ionic status in both genotypes, Pusa 2002 was more salt tolerant and ensured higher AM fungal colonization, plant biomass and nutrient content with favourable ion status under salinity. Although all AM fungi reduced negative effects of salt stress, R. irregularis (alone or in combination with F. mosseae) displayed highest efficiency under salinity, resulting in highest biomass, yield, nutrient uptake and improved membrane stability with favourable K(+)/Na(+) and Ca(2+)/Na(+) ratios in the host plant. Higher effectiveness of R. irregularis correlated with higher root colonization, indicating that the symbiosis formed by R. irregularis had more stable viability and efficiency under salt stress. These findings enhance understanding of the functional diversity of AM fungi in ameliorating plant salt stress tolerance and suggest the potential use of R. irregularis for increasing Cajanus cajan productivity in saline soils. PMID:25155616

  3. Effectiveness of native and exotic arbuscular mycorrhizal fungi on nutrient uptake and ion homeostasis in salt-stressed Cajanus cajan L. (Millsp.) genotypes.

    PubMed

    Garg, Neera; Pandey, Rekha

    2015-04-01

    Soil salinity is an increasing problem worldwide, restricting plant growth and production. Research findings show that arbuscular mycorrhizal (AM) fungi have the potential to reduce negative effects of salinity. However, plant growth responses to AM fungi vary as a result of genetic variation in mycorrhizal colonization and plant growth responsiveness. Thus, profitable use of AM requires selection of a suitable combination of host plant and fungal partner. A greenhouse experiment was conducted to compare effectiveness of a native AM fungal inoculum sourced from saline soil and two single exotic isolates, Funneliformis mossseae and Rhizophagus irregularis (single or dual mix), on Cajanus cajan (L.) Millsp. genotypes (Paras and Pusa 2002) under salt stress (0-100 mM NaCl). While salinity reduced plant biomass and disturbed ionic status in both genotypes, Pusa 2002 was more salt tolerant and ensured higher AM fungal colonization, plant biomass and nutrient content with favourable ion status under salinity. Although all AM fungi reduced negative effects of salt stress, R. irregularis (alone or in combination with F. mosseae) displayed highest efficiency under salinity, resulting in highest biomass, yield, nutrient uptake and improved membrane stability with favourable K(+)/Na(+) and Ca(2+)/Na(+) ratios in the host plant. Higher effectiveness of R. irregularis correlated with higher root colonization, indicating that the symbiosis formed by R. irregularis had more stable viability and efficiency under salt stress. These findings enhance understanding of the functional diversity of AM fungi in ameliorating plant salt stress tolerance and suggest the potential use of R. irregularis for increasing Cajanus cajan productivity in saline soils.

  4. Assessment of arbuscular mycorrhizal fungi status and heavy metal accumulation characteristics of tree species in a lead-zinc mine area: potential applications for phytoremediation.

    PubMed

    Yang, Yurong; Liang, Yan; Ghosh, Amit; Song, Yingying; Chen, Hui; Tang, Ming

    2015-09-01

    To select suitable tree species associated with arbuscular mycorrhizal fungi (AMF) for phytoremediation of heavy metal (HM) contaminated area, we measured the AMF status and heavy metal accumulation in plant tissues in a lead-zinc mine area, Northwest China. All 15 tree species were colonized by AM fungi in our investigation. The mycorrhizal frequency (F%), mycorrhizal colonization intensity (M%) and spore density (SP) reduced concomitantly with increasing Pb and Zn levels; however, positive correlations were found between arbuscule density (A%) and soil total/DTPA-extractable Pb concentrations. The average concentrations of Pb, Zn, Cu and Cd in plant samples were 168.21, 96.61, 41.06, and 0.79 mg/kg, respectively. Populus purdomii Rehd. accumulated the highest concentrations of Zn (432.08 mg/kg) and Cu (140.85 mg/kg) in its leaves. Considerable amount of Pb (712.37 mg/kg) and Cd (3.86 mg/kg) were concentrated in the roots of Robinia pseudoacacia Linn. and Populus simonii Carr., respectively. Plants developed different strategies to survive in HM stress environment: translocating more essential metals (Zn and Cu) into the aerial parts, while retaining more toxic heavy metals (Pb and Cd) in the roots to protect the above-ground parts from damage. According to the translocation factor (TF), bioconcentration factor (BCF), growth rate and biomass production, five tree species (Ailanthus altissima (Mill.) Swingle, Cotinus coggygria Scop., P. simonii, P. purdomii, and R. pseudoacacia) were considered to be the most suitable candidates for phytoextraction and/or phytostabilization purposes. Redundancy analysis (RDA) showed that the efficiency of phytoremediation was enhanced by AM symbioses, and soil pH, Pb, Zn, and Cd levels were the main factors influencing the HM accumulation characteristics of plants. PMID:25929455

  5. Assessment of arbuscular mycorrhizal fungi status and heavy metal accumulation characteristics of tree species in a lead-zinc mine area: potential applications for phytoremediation.

    PubMed

    Yang, Yurong; Liang, Yan; Ghosh, Amit; Song, Yingying; Chen, Hui; Tang, Ming

    2015-09-01

    To select suitable tree species associated with arbuscular mycorrhizal fungi (AMF) for phytoremediation of heavy metal (HM) contaminated area, we measured the AMF status and heavy metal accumulation in plant tissues in a lead-zinc mine area, Northwest China. All 15 tree species were colonized by AM fungi in our investigation. The mycorrhizal frequency (F%), mycorrhizal colonization intensity (M%) and spore density (SP) reduced concomitantly with increasing Pb and Zn levels; however, positive correlations were found between arbuscule density (A%) and soil total/DTPA-extractable Pb concentrations. The average concentrations of Pb, Zn, Cu and Cd in plant samples were 168.21, 96.61, 41.06, and 0.79 mg/kg, respectively. Populus purdomii Rehd. accumulated the highest concentrations of Zn (432.08 mg/kg) and Cu (140.85 mg/kg) in its leaves. Considerable amount of Pb (712.37 mg/kg) and Cd (3.86 mg/kg) were concentrated in the roots of Robinia pseudoacacia Linn. and Populus simonii Carr., respectively. Plants developed different strategies to survive in HM stress environment: translocating more essential metals (Zn and Cu) into the aerial parts, while retaining more toxic heavy metals (Pb and Cd) in the roots to protect the above-ground parts from damage. According to the translocation factor (TF), bioconcentration factor (BCF), growth rate and biomass production, five tree species (Ailanthus altissima (Mill.) Swingle, Cotinus coggygria Scop., P. simonii, P. purdomii, and R. pseudoacacia) were considered to be the most suitable candidates for phytoextraction and/or phytostabilization purposes. Redundancy analysis (RDA) showed that the efficiency of phytoremediation was enhanced by AM symbioses, and soil pH, Pb, Zn, and Cd levels were the main factors influencing the HM accumulation characteristics of plants.

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

    SciTech Connect

    Rillig, M.C.; Klironomos, J.N.; Allen, M.F.

    1995-09-01

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

  7. Biology and applications of mycorrhizal fungi.

    PubMed

    Sharma, S; Madan, M; Vasudevan, P

    1997-12-01

    Mycorrhizae have been shown to increase growth and yield of plants. They have been identified with both nutrient mobilization and nutrient cycling. Arbuscular (or endo-) mycorrhizae play a significant role in agriculture and most natural ecosystems, whereas ectomycorrhizae have a great potential in forestry and wasteland regeneration. The use of mycorrhizal fungi would reduce dependence on chemical fertilizers besides minimizing environmental pollution. The present review addresses the progress that there has been in the area of the ecto- and endomycorrhizae. It also examines the potential of field applications of mycorrhizal biotechnology in agriculture and forestry.

  8. A study on the effects of lead, cadmium and phosphorus on the lead and cadmium uptake efficacy of Viola baoshanensis inoculated with arbuscular mycorrhizal fungi.

    PubMed

    Zhong, Wei-liang; Li, Jin-tian; Chen, Ya-ting; Shu, Wen-sheng; Liao, Bin

    2012-09-01

    The effect of indigenous arbuscular mycorrhizal (AM) fungi on lead (Pb) and cadmium (Cd) uptake by the hyperaccumulator plant Viola baoshanensis was studied in greenhouse pot experiments. Seedlings of V. baoshanensis inoculated without or with indigenous AM fungi were grown in paddy soil with the addition of Pb at 0, 500, 1000 and 1500 mg kg(-1), or of Cd at 0, 50,100, 200 mg kg(-1), or in mine soil with the addition of phosphorus at 0, 50, 250, 500 mg kg(-1). AM colonization increased shoot biomass at low phosphorus levels, and this beneficial effect was diminished or reversed by high phosphorus availability. AM colonization decreased shoot Cd concentrations regardless of the availability of Cd and phosphorus, but the mechanisms involved varied with Cd availability. At low Cd bioavailability, reduced Cd uptake was due to decreased Cd translocation from the roots to the shoots, whereas that was attributed to reduced root uptake at high Cd bioavailability. In contrast, the effect of AM colonization on shoot Pb varied with the availability of phosphorous and Pb. Our results show that the interactions between V. baoshanensis and indigenous AM fungi were modified by the availability of Pb, Cd and phosphorus.

  9. 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.

    PubMed

    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. PMID:26184906

  10. Arbuscular mycorrhizal fungi are an alternative to the application of chemical fertilizer in the production of the medicinal and aromatic plant Coriandrum sativum L.

    PubMed

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

    2016-01-01

    The widespread use of agrochemicals is detrimental to the environment and may exert harmful effects on human health. The consumer demand for organic food plants has been increasing. There is thus a rising need for alternatives to agrochemicals that can foster sustainable plant production. The aim of this study was to evaluate the potential use of an arbuscular mycorrhizal (AM) fungus as an alternative to application of chemical fertilizer for improving growth performance of the medicinal and aromatic plant Coriandrum sativum. Plants were inoculated with the AM fungus Rhizophagus irregularis BEG163 and/or supplemented with a commercial chemical fertilizer (Plant Marvel, Nutriculture Bent Special) in agricultural soil. Plant growth, nutrition, and development of AM fungus were assessed. Plants inoculated with R. irregularis and those supplemented with chemical fertilizer displayed significantly improved growth performances when compared with controls. There were no significant differences in total fresh weight between plants inoculated with R. irregularis or those supplemented with chemical fertilizer. Leaf chlorophyll a + b (82%), shoot nitrogen (44%), phosphorus (254%), and potassium (27%) concentrations increased in plants inoculated with R. irregularis compared to controls. Application of chemical fertilizer inhibited root mycorrhizal colonization and the length of the extraradical mycelium of R. irregularis. Inoculation with R. irregularis was equally or more efficient than application of chemical fertilizer in promoting growth and nutrition of C. sativum. AM fungi may thus contribute to improve biologically based production of food plants and reduce the dependence on agrochemicals in agriculture. PMID:27077563

  11. Plant tolerance to mercury in a contaminated soil is enhanced by the combined effects of humic matter addition and inoculation with arbuscular mycorrhizal fungi.

    PubMed

    Cozzolino, V; De Martino, A; Nebbioso, A; Di Meo, V; Salluzzo, A; Piccolo, A

    2016-06-01

    In a greenhouse pot experiment, lettuce plants (Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg(-1) of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops. PMID:26931658

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

    PubMed

    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.

  13. Spatio-temporal dynamics of arbuscular mycorrhizal fungi associated with glomalin-related soil protein and soil enzymes in different managed semiarid steppes.

    PubMed

    Wang, Qi; Bao, Yuying; Liu, Xiaowei; Du, Guoxin

    2014-10-01

    Temporal and spatial patterns of arbuscular mycorrhizal fungi (AMF) and glomalin and soil enzyme activities were investigated in different managed semiarid steppes located in Inner Mongolia, North China. Soils were sampled in a depth up to 30 cm from non-grazed, overgrazed, and naturally restored steppes from June to September. Roots of Leymus chinense (Trin.) Tzvel. and Stipagrandis P. Smirn. were also collected over the same period. Results showed that overgrazing significantly decreased the total mycorrhizal colonization of S. grandis; total colonization of L. chinensis roots was not significantly different in the three managed steppes. Nineteen AMF species belonging to six genera were isolated. Funneliformis and Glomus were dominant genera in all three steppes. Spore density and species richness were mainly influenced by an interaction between plant growth stage and management system (P < 0.001). Spore densities were higher in 0-10-cm soil depth. AMF species richness was significantly positively correlated with soil acid phosphatase activity, alkaline phosphatase activity, and two Bradford-reactive soil protein (BRSP) fractions (P < 0.01). It is concluded that the dynamics of AMF have highly temporal and spatial patterns that are related to soil glomalin and phosphatase activity in different managed semiarid steppes. Based on these observations, AMF communities could be useful indicators for evaluating soil quality and function of semiarid grassland ecosystems.

  14. Improvement of nutritional quality of greenhouse-grown lettuce by arbuscular mycorrhizal fungi is conditioned by the source of phosphorus nutrition.

    PubMed

    Baslam, Marouane; Pascual, Inmaculada; Sánchez-Díaz, Manuel; Erro, Javier; García-Mina, José María; Goicoechea, Nieves

    2011-10-26

    The improvement of the nutritional quality of lettuce by its association with arbuscular mycorrhizal fungi (AMF) has been recently reported in a previous study. The aim of this research was to evaluate if the fertilization with three P sources differing in water solubility affects the effectiveness of AMF for improving lettuce growth and nutritional quality. The application of either water-soluble P sources (Hewitt's solution and single superphosphate) or the water-insoluble (WI) fraction of a "rhizosphere-controlled fertilizer" did not exert negative effects on the establishment of the mycorrhizal symbiosis. AMF improved lettuce growth and nutritional quality. Nevertheless, the effect was dependent on the source of P and cultivar. Batavia Rubia Munguía (green cultivar) benefited more than Maravilla de Verano (red cultivar) in terms of mineral nutrients, total soluble sugars, and ascorbate contents. The association of lettuce with AMF resulted in greater quantities of anthocyanins in plants fertilized with WI, carotenoids when plants received either Hewitt's solution or WI, and phenolics regardless of the P fertilizer applied. PMID:21913649

  15. Spatio-temporal dynamics of arbuscular mycorrhizal fungi associated with glomalin-related soil protein and soil enzymes in different managed semiarid steppes.

    PubMed

    Wang, Qi; Bao, Yuying; Liu, Xiaowei; Du, Guoxin

    2014-10-01

    Temporal and spatial patterns of arbuscular mycorrhizal fungi (AMF) and glomalin and soil enzyme activities were investigated in different managed semiarid steppes located in Inner Mongolia, North China. Soils were sampled in a depth up to 30 cm from non-grazed, overgrazed, and naturally restored steppes from June to September. Roots of Leymus chinense (Trin.) Tzvel. and Stipagrandis P. Smirn. were also collected over the same period. Results showed that overgrazing significantly decreased the total mycorrhizal colonization of S. grandis; total colonization of L. chinensis roots was not significantly different in the three managed steppes. Nineteen AMF species belonging to six genera were isolated. Funneliformis and Glomus were dominant genera in all three steppes. Spore density and species richness were mainly influenced by an interaction between plant growth stage and management system (P < 0.001). Spore densities were higher in 0-10-cm soil depth. AMF species richness was significantly positively correlated with soil acid phosphatase activity, alkaline phosphatase activity, and two Bradford-reactive soil protein (BRSP) fractions (P < 0.01). It is concluded that the dynamics of AMF have highly temporal and spatial patterns that are related to soil glomalin and phosphatase activity in different managed semiarid steppes. Based on these observations, AMF communities could be useful indicators for evaluating soil quality and function of semiarid grassland ecosystems. PMID:24687605

  16. Differential modulation of host plant delta13C and delta18O by native and nonnative arbuscular mycorrhizal fungi in a semiarid environment.

    PubMed

    Querejeta, J I; Allen, M F; Caravaca, F; Roldán, A

    2006-01-01

    Native, drought-adapted arbuscular mycorrhizal fungi (AMF) often improve host-plant performance to a greater extent than nonnative AMF in dry environments. However, little is known about the physiological basis for this differential plant response. Seedlings of Olea europaea and Rhamnus lycioides were inoculated with either a mixture of eight native Glomus species or with the nonnative Glomus claroideum before field transplanting in a semiarid area. Inoculation with native AMF produced the greatest improvement in nutrient and water status as well as in long-term growth for both Olea and Rhamnus. Foliar delta18O measurements indicated that native AMF enhanced stomatal conductance to a greater extent than nonnative AMF in Olea and Rhamnus.delta13C data showed that intrinsic water-use efficiency in Olea was differentially stimulated by native AMF compared with nonnative AMF. Our results suggest that modulation of leaf gas exchange by native, drought-adapted AMF is critical to the long-term performance of host plants in semiarid environments. delta18O can provide a time-integrated measure of the effect of mycorrhizal infection on host-plant water relations.

  17. Differential modulation of host plant delta13C and delta18O by native and nonnative arbuscular mycorrhizal fungi in a semiarid environment.

    PubMed

    Querejeta, J I; Allen, M F; Caravaca, F; Roldán, A

    2006-01-01

    Native, drought-adapted arbuscular mycorrhizal fungi (AMF) often improve host-plant performance to a greater extent than nonnative AMF in dry environments. However, little is known about the physiological basis for this differential plant response. Seedlings of Olea europaea and Rhamnus lycioides were inoculated with either a mixture of eight native Glomus species or with the nonnative Glomus claroideum before field transplanting in a semiarid area. Inoculation with native AMF produced the greatest improvement in nutrient and water status as well as in long-term growth for both Olea and Rhamnus. Foliar delta18O measurements indicated that native AMF enhanced stomatal conductance to a greater extent than nonnative AMF in Olea and Rhamnus.delta13C data showed that intrinsic water-use efficiency in Olea was differentially stimulated by native AMF compared with nonnative AMF. Our results suggest that modulation of leaf gas exchange by native, drought-adapted AMF is critical to the long-term performance of host plants in semiarid environments. delta18O can provide a time-integrated measure of the effect of mycorrhizal infection on host-plant water relations. PMID:16411940

  18. Arbuscular mycorrhizal fungi are an alternative to the application of chemical fertilizer in the production of the medicinal and aromatic plant Coriandrum sativum L.

    PubMed

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

    2016-01-01

    The widespread use of agrochemicals is detrimental to the environment and may exert harmful effects on human health. The consumer demand for organic food plants has been increasing. There is thus a rising need for alternatives to agrochemicals that can foster sustainable plant production. The aim of this study was to evaluate the potential use of an arbuscular mycorrhizal (AM) fungus as an alternative to application of chemical fertilizer for improving growth performance of the medicinal and aromatic plant Coriandrum sativum. Plants were inoculated with the AM fungus Rhizophagus irregularis BEG163 and/or supplemented with a commercial chemical fertilizer (Plant Marvel, Nutriculture Bent Special) in agricultural soil. Plant growth, nutrition, and development of AM fungus were assessed. Plants inoculated with R. irregularis and those supplemented with chemical fertilizer displayed significantly improved growth performances when compared with controls. There were no significant differences in total fresh weight between plants inoculated with R. irregularis or those supplemented with chemical fertilizer. Leaf chlorophyll a + b (82%), shoot nitrogen (44%), phosphorus (254%), and potassium (27%) concentrations increased in plants inoculated with R. irregularis compared to controls. Application of chemical fertilizer inhibited root mycorrhizal colonization and the length of the extraradical mycelium of R. irregularis. Inoculation with R. irregularis was equally or more efficient than application of chemical fertilizer in promoting growth and nutrition of C. sativum. AM fungi may thus contribute to improve biologically based production of food plants and reduce the dependence on agrochemicals in agriculture.

  19. Contribution of arbuscular mycorrhizal fungi and/or bacteria to enhancing plant drought tolerance under natural soil conditions: effectiveness of autochthonous or allochthonous strains.

    PubMed

    Ortiz, N; Armada, E; Duque, E; Roldán, A; Azcón, R

    2015-02-01

    Autochthonous microorganisms [a consortium of arbuscular-mycorrhizal (AM) fungi and Bacillus thuringiensis (Bt)] were assayed and compared to Rhizophagus intraradices (Ri), Bacillus megaterium (Bm) or Pseudomonas putida (Psp) and non-inoculation on Trifolium repens in a natural arid soil under drought conditions. The autochthonous bacteria Bt and the allochthonous bacteria Psp increased nutrients and the relative water content and decreased stomatal conductance, electrolyte leakage, proline and APX activity, indicating their abilities to alleviate the drought stress. Mycorrhizal inoculation significantly enhanced plant growth, nutrient uptake and the relative water content, particularly when associated with specific bacteria minimizing drought stress-imposed effects. Specific combinations of autochthonous or allochthonous inoculants also contributed to plant drought tolerance by changing proline and antioxidative activities. However, non-inoculated plants had low relative water and nutrients contents, shoot proline accumulation and glutathione reductase activity, but the highest superoxide dismutase activity, stomatal conductance and electrolyte leakage. Microbial activities irrespective of the microbial origin seem to be coordinately functioning in the plant as an adaptive response to modulated water stress tolerance and minimizing the stress damage. The autochthonous AM fungi with Bt or Psp and those allochthonous Ri with Bm or Psp inoculants increased water stress alleviation. The autochthonous Bt showed the greatest ability to survive under high osmotic stress compared to the allochthonous strains, but when single inoculated or associated with Ri or AM fungi were similarly efficient in terms of physiological and nutritional status and in increasing plant drought tolerance, attenuating and compensating for the detrimental effect of water limitation.

  20. Contribution of arbuscular mycorrhizal fungi and/or bacteria to enhancing plant drought tolerance under natural soil conditions: effectiveness of autochthonous or allochthonous strains.

    PubMed

    Ortiz, N; Armada, E; Duque, E; Roldán, A; Azcón, R

    2015-02-01

    Autochthonous microorganisms [a consortium of arbuscular-mycorrhizal (AM) fungi and Bacillus thuringiensis (Bt)] were assayed and compared to Rhizophagus intraradices (Ri), Bacillus megaterium (Bm) or Pseudomonas putida (Psp) and non-inoculation on Trifolium repens in a natural arid soil under drought conditions. The autochthonous bacteria Bt and the allochthonous bacteria Psp increased nutrients and the relative water content and decreased stomatal conductance, electrolyte leakage, proline and APX activity, indicating their abilities to alleviate the drought stress. Mycorrhizal inoculation significantly enhanced plant growth, nutrient uptake and the relative water content, particularly when associated with specific bacteria minimizing drought stress-imposed effects. Specific combinations of autochthonous or allochthonous inoculants also contributed to plant drought tolerance by changing proline and antioxidative activities. However, non-inoculated plants had low relative water and nutrients contents, shoot proline accumulation and glutathione reductase activity, but the highest superoxide dismutase activity, stomatal conductance and electrolyte leakage. Microbial activities irrespective of the microbial origin seem to be coordinately functioning in the plant as an adaptive response to modulated water stress tolerance and minimizing the stress damage. The autochthonous AM fungi with Bt or Psp and those allochthonous Ri with Bm or Psp inoculants increased water stress alleviation. The autochthonous Bt showed the greatest ability to survive under high osmotic stress compared to the allochthonous strains, but when single inoculated or associated with Ri or AM fungi were similarly efficient in terms of physiological and nutritional status and in increasing plant drought tolerance, attenuating and compensating for the detrimental effect of water limitation. PMID:25462971

  1. Synergistic interaction of Rhizobium leguminosarum bv. viciae and arbuscular mycorrhizal fungi as a plant growth promoting biofertilizers for faba bean (Vicia faba L.) in alkaline soil.

    PubMed

    Abd-Alla, Mohamed Hemida; El-Enany, Abdel-Wahab Elsadek; Nafady, Nivien Allam; Khalaf, David Mamdouh; Morsy, Fatthy Mohamed

    2014-01-20

    Egyptian soils are generally characterized by slightly alkaline to alkaline pH values (7.5-8.7) which are mainly due to its dry environment. In arid and semi-arid regions, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. Alkaline soils have fertility problems due to poor physical properties which adversely affect the growth and the yield of crops. Therefore, this study was devoted to investigating the synergistic interaction of Rhizobium and arbuscular mycorrhizal fungi for improving growth of faba bean grown in alkaline soil. A total of 20 rhizobial isolates and 4 species of arbuscular mycorrhizal fungi (AMF) were isolated. The rhizobial isolates were investigated for their ability to grow under alkaline stress. Out of 20 isolates 3 isolates were selected as tolerant isolates. These 3 rhizobial isolates were identified on the bases of the sequences of the gene encoding 16S rRNA and designated as Rhizobium sp. Egypt 16 (HM622137), Rhizobium sp. Egypt 27 (HM622138) and Rhizobium leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The best alkaline tolerant was R. leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The effect of R. leguminosarum bv. viciae STDF-Egypt 19 and mixture of AMF (Acaulospora laevis, Glomus geosporum, Glomus mosseae and Scutellospora armeniaca) both individually and in combination on nodulation, nitrogen fixation and growth of Vicia faba under alkalinity stress were assessed. A significant increase over control in number and mass of nodules, nitrogenase activity, leghaemoglobin content of nodule, mycorrhizal colonization, dry mass of root and shoot was recorded in dual inoculated plants than plants with individual inoculation. The enhancement of nitrogen fixation of faba bean could be attributed to AMF facilitating the mobilization of certain elements such as P, Fe, K and other minerals that involve in synthesis of nitrogenase and leghaemoglobin. Thus it is

  2. Plant hormones as signals in arbuscular mycorrhizal symbiosis.

    PubMed

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

    2014-06-01

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

  3. Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

    NASA Astrophysics Data System (ADS)

    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.

  4. Host and non-host roots in rice: cellular and molecular approaches reveal differential responses to arbuscular mycorrhizal fungi

    PubMed Central

    Fiorilli, Valentina; Vallino, Marta; Biselli, Chiara; Faccio, Antonella; Bagnaresi, Paolo; Bonfante, Paola

    2015-01-01

    Oryza sativa, a model plant for Arbuscular Mycorrhizal (AM) symbiosis, has both host and non-host roots. Large lateral (LLR) and fine lateral (FLR) roots display opposite responses: LLR support AM colonization, but FLR do not. Our research aimed to study the molecular, morphological and physiological aspects related to the non-host behavior of FLR. RNA-seq analysis revealed that LLR and FLR displayed divergent expression profiles, including changes in many metabolic pathways. Compared with LLR, FLR showed down-regulation of genes instrumental for AM establishment and gibberellin signaling, and a higher expression of nutrient transporters. Consistent with the transcriptomic data, FLR had higher phosphorus content. Light and electron microscopy demonstrated that, surprisingly, in the Selenio cultivar, FLR have a two-layered cortex, which is theoretically compatible with AM colonization. According to RNA-seq, a gibberellin inhibitor treatment increased anticlinal divisions leading to a higher number of cortex cells in FLR. We propose that some of the differentially regulated genes that lead to the anatomical and physiological properties of the two root types also function as genetic factors regulating fungal colonization. The rice root apparatus offers a unique tool to study AM symbiosis, allowing direct comparisons of host and non-host roots in the same individual plant. PMID:26322072

  5. Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

    PubMed Central

    Jiang, Qiu-Yun; Zhuo, Feng; Long, Shi-Hui; Zhao, Hai-Di; Yang, Dan-Jing; Ye, Zhi-Hong; Li, Shao-Shan; Jing, Yuan-Xiao

    2016-01-01

    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. PMID:26892768

  6. Host and non-host roots in rice: cellular and molecular approaches reveal differential responses to arbuscular mycorrhizal fungi.

    PubMed

    Fiorilli, Valentina; Vallino, Marta; Biselli, Chiara; Faccio, Antonella; Bagnaresi, Paolo; Bonfante, Paola

    2015-01-01

    Oryza sativa, a model plant for Arbuscular Mycorrhizal (AM) symbiosis, has both host and non-host roots. Large lateral (LLR) and fine lateral (FLR) roots display opposite responses: LLR support AM colonization, but FLR do not. Our research aimed to study the molecular, morphological and physiological aspects related to the non-host behavior of FLR. RNA-seq analysis revealed that LLR and FLR displayed divergent expression profiles, including changes in many metabolic pathways. Compared with LLR, FLR showed down-regulation of genes instrumental for AM establishment and gibberellin signaling, and a higher expression of nutrient transporters. Consistent with the transcriptomic data, FLR had higher phosphorus content. Light and electron microscopy demonstrated that, surprisingly, in the Selenio cultivar, FLR have a two-layered cortex, which is theoretically compatible with AM colonization. According to RNA-seq, a gibberellin inhibitor treatment increased anticlinal divisions leading to a higher number of cortex cells in FLR. We propose that some of the differentially regulated genes that lead to the anatomical and physiological properties of the two root types also function as genetic factors regulating fungal colonization. The rice root apparatus offers a unique tool to study AM symbiosis, allowing direct comparisons of host and non-host roots in the same individual plant. PMID:26322072

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

    PubMed

    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.

  8. Breakdown and delayed cospeciation in the arbuscular mycorrhizal mutualism

    PubMed Central

    Merckx, Vincent; Bidartondo, Martin I

    2008-01-01

    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. PMID:18270159

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

    PubMed

    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.

  10. Communities of Arbuscular Mycorrhizal Fungi in the Roots of Pyrus pyrifolia var. culta (Japanese Pear) in Orchards with Variable Amounts of Soil-Available Phosphorus

    PubMed Central

    Yoshimura, Yuko; Ido, Akifumi; Iwase, Koji; Matsumoto, Teruyuki; Yamato, Masahide

    2013-01-01

    We examined the colonization rate and communities of arbuscular mycorrhizal fungi (AMF) in the roots of Pyrus pyrifolia var. culta (Japanese pear) in orchards to investigate the effect of phosphorus (P) fertilization on AMF. Soil cores containing the roots of Japanese pear were collected from 13 orchards in Tottori Prefecture, Japan. Soil-available P in the examined orchards was 75.7 to 1,200 mg kg−1, showing the extreme accumulation of soil P in many orchards. The AMF colonization rate was negatively correlated with soil-available P (P <0.01). AMF communities were examined on the basis of the partial fungal DNA sequences of the nuclear small-subunit ribosomal RNA gene (SSU rDNA) amplified by AMF-specific primers AML1 and AML2. The obtained AMF sequences were divided into 14 phylotypes, and the number of phylotypes (species richness) was also negatively correlated with soil-available P (P <0.05). It was also suggested that some AM fungi may be adapted to high soil-available P conditions. Redundancy analysis showed the significant effects of soil pH, available P in soil, and P content in leaves of P. pyrifolia var. culta trees on AMF distribution. These results suggested that the accumulation of soil-available P affected AMF communities in the roots of Japanese pear in the orchard environment. PMID:23257910

  11. Effect of ryegrass (Lolium perenne L.) roots inoculation using different arbuscular mycorrhizal fungi (AMF) species on sorption of iron-cyanide (Fe-CN) complexes

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Soils and groundwater on sites of the former Manufactured Gas Plants (MGPs) are contaminated with various complex iron-cyanides (Fe-CN). Phytoremediation is a promising tool in stabilization and remediation of Fe-CN affected soils, however, it can be a challenging task due to extreme adverse and toxic conditions. Phytoremediation may be enhanced via rhizosphere microbial activity, which can cooperate on the degradation, transformation and uptake of the contaminants. Recently, increasing number of scientist reports improved plants performance in the removal of toxic compounds with the support of arbuscular mycorrhizae fungi (AMF). Series of batch experiments using potassium hexacyanoferrate (II) solutions, in varying concentrations, were used to study the effect of ryegrass roots (Lolium perenne L.) inoculation with Rhizophagus irregularis and a mixture of Rhizophagus irregularis, Funneliformis mosseae, Rhizophagus aggregatus, and Claroideoglomus etunicatum on Fe-CN sorption. Results indicated significantly higher colonization of R. irregularis than for the mixture of AMF species on ryegrass roots. Sorption experiments revealed significantly higher reduction of total CN and free CN content in the mycorrhizal roots, indicating greater cyanide decrease in the treatment inoculated with R. irregularis. Our study indicates contribution of AM fungi in phytoremediation of Fe-CN contaminated soil.

  12. Increased Diversity of Arbuscular Mycorrhizal Fungi in a Long-Term Field Experiment via Application of Organic Amendments to a Semiarid Degraded Soil▿ †

    PubMed Central

    del Mar Alguacil, Maria; Díaz-Pereira, Elvira; Caravaca, Fuensanta; Fernández, Diego A.; Roldán, Antonio

    2009-01-01

    In this study, we tested whether communities of arbuscular mycorrhizal (AM) fungi associated with roots of plant species forming vegetative cover as well as some soil parameters (amounts of phosphatase and glomalin-related soil protein, microbial biomass C and N concentrations, amount of P available, and aggregate stability) were affected by different amounts (control, 6.5 kg m−2, 13.0 kg m−2, 19.5 kg m−2, and 26.0 kg m−2) of an urban refuse (UR) 19 years after its application to a highly eroded, semiarid soil. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, single-stranded conformation polymorphism analysis, sequencing, and phylogenetic analyses. One hundred sixteen SSU rRNA sequences were analyzed, and nine AM fungal types belonging to Glomus groups A and B were identified: three of them were present in all the plots that had received UR, and six appeared to be specific to certain amendment doses. The community of AM fungi was more diverse after the application of the different amounts of UR. The values of all the soil parameters analyzed increased proportionally with the dose of amendment applied. In conclusion, the application of organic wastes enhanced soil microbial activities and aggregation, and the AM fungal diversity increased, particularly when a moderate dose of UR (13.0 kg m−2) was applied. PMID:19429562

  13. Communities of arbuscular mycorrhizal fungi in the roots of Pyrus pyrifolia var. culta (Japanese pear) in orchards with variable amounts of soil-available phosphorus.

    PubMed

    Yoshimura, Yuko; Ido, Akifumi; Iwase, Koji; Matsumoto, Teruyuki; Yamato, Masahide

    2013-01-01

    We examined the colonization rate and communities of arbuscular mycorrhizal fungi (AMF) in the roots of Pyrus pyrifolia var. culta (Japanese pear) in orchards to investigate the effect of phosphorus (P) fertilization on AMF. Soil cores containing the roots of Japanese pear were collected from 13 orchards in Tottori Prefecture, Japan. Soil-available P in the examined orchards was 75.7 to 1,200 mg kg(-1), showing the extreme accumulation of soil P in many orchards. The AMF colonization rate was negatively correlated with soil-available P (P <0.01). AMF communities were examined on the basis of the partial fungal DNA sequences of the nuclear small-subunit ribosomal RNA gene (SSU rDNA) amplified by AMF-specific primers AML1 and AML2. The obtained AMF sequences were divided into 14 phylotypes, and the number of phylotypes (species richness) was also negatively correlated with soil-available P (P <0.05). It was also suggested that some AM fungi may be adapted to high soil-available P conditions. Redundancy analysis showed the significant effects of soil pH, available P in soil, and P content in leaves of P. pyrifolia var. culta trees on AMF distribution. These results suggested that the accumulation of soil-available P affected AMF communities in the roots of Japanese pear in the orchard environment.

  14. Inoculation of tomato seedlings with Trichoderma Harzianum and Arbuscular Mycorrhizal Fungi and their effect on growth and control of wilt in tomato seedlings.

    PubMed

    Mwangi, Margaret W; Monda, Ethel O; Okoth, Sheila A; Jefwa, Joyce M

    2011-04-01

    A green house study was conducted to investigate the ability of an isolate of Trichoderma harzianum (P52) and arbuscular mycorrhizal fungi (AMF) in enhancing growth and control of a wilt pathogen caused by Fusarium oxysporum f. sp. lycopersici in tomato seedlings. The plants were grown in plastic pots filled with sterilized soils. There were four treatments applied as follows; P52, AMF, AMF + P52 and a control. A completely randomized design was used and growth measurements and disease assessment taken after 3, 6 and 9 weeks. Treatments that significantly (P < 0.05) enhanced heights and root dry weights were P52, AMF and a treatment with a combination of both P52 and AMF when compared the control. The treatment with both P52 and AMF significantly (P < 0.05) enhanced all growth parameters (heights; shoot and root dry weight) investigated compared to the control. Disease severity was generally lower in tomato plants grown with isolate P52 and AMF fungi either individually or when combined together, though the effect was not statistically significant (P≥ 0.05). A treatment combination of P52 + AMF had less trend of severity as compared to each individual fungus. T. harzianum and AMF can be used to enhance growth in tomato seedlings. PMID:24031662

  15. Group I intron-mediated trans-splicing in mitochondria of Gigaspora rosea and a robust phylogenetic affiliation of arbuscular mycorrhizal fungi with Mortierellales.

    PubMed

    Nadimi, Maryam; Beaudet, Denis; Forget, Lise; Hijri, Mohamed; Lang, B Franz

    2012-09-01

    Gigaspora rosea is a member of the arbuscular mycorrhizal fungi (AMF; Glomeromycota) and a distant relative of Glomus species that are beneficial to plant growth. To allow for a better understanding of Glomeromycota, we have sequenced the mitochondrial DNA of G. rosea. A comparison with Glomus mitochondrial genomes reveals that Glomeromycota undergo insertion and loss of mitochondrial plasmid-related sequences and exhibit considerable variation in introns. The gene order between the two species is almost completely reshuffled. Furthermore, Gigaspora has fragmented cox1 and rns genes, and an unorthodox initiator tRNA that is tailored to decoding frequent UUG initiation codons. For the fragmented cox1 gene, we provide evidence that its RNA is joined via group I-mediated trans-splicing, whereas rns RNA remains in pieces. According to our model, the two cox1 precursor RNA pieces are brought together by flanking cox1 exon sequences that form a group I intron structure, potentially in conjunction with the nad5 intron 3 sequence. Finally, we present analyses that address the controversial phylogenetic association of Glomeromycota within fungi. According to our results, Glomeromycota are not a separate group of paraphyletic zygomycetes but branch together with Mortierellales, potentially also Harpellales.

  16. Three new species of arbuscular mycorrhizal fungi discovered at one location in a desert of Oman: Diversispora omaniana, Septoglomus nakheelum and Rhizophagus arabicus.

    PubMed

    Symanczik, Sarah; Błaszkowski, Janusz; Chwat, Gerard; Boller, Thomas; Wiemken, Andres; Al-Yahya'ei, Mohamed N

    2014-01-01

    Three new species of arbuscular mycorrhizal (AM) fungi (Glomeromycota) were isolated from soil samples collected from a hyperarid sandy plain of South Arabia. Morphological characteristics of the spores clearly differentiated them from closely related AM species. Molecular analyses were performed on rDNA sequences obtained from single spores including a ~1700 bp region comprising partial SSU, ITS, partial LSU and the ~600 bp ITS region only. The phylogenetic trees based on these regions showed that the three species belong to well described genera but are clearly distinct from known species. Consequently, we describe them here as Diversispora omaniana, Septoglomus nakheelum and Rhizophagus arabicus spp. nov. D. omaniana and R. arabicus were isolated from the native, arid habitat, while S. nakheelum was isolated from a nearby irrigated date palm plantation. The discovery of three new species of AM fungi from this location suggests that a number of additional undescribed AM taxa may be present in such desert ecosystems. Further work to understand the diversity and functional significance of these new AM taxa may offer new opportunities for conservation, re-vegetation, and sustainable agriculture in extremely arid environments.

  17. Arbuscular mycorrhizal fungi and plant growth-promoting pseudomonads increases anthocyanin concentration in strawberry fruits (Fragaria x ananassa var. Selva) in conditions of reduced fertilization.

    PubMed

    Lingua, Guido; Bona, Elisa; Manassero, Paola; Marsano, Francesco; Todeschini, Valeria; Cantamessa, Simone; Copetta, Andrea; D'Agostino, Giovanni; Gamalero, Elisa; Berta, Graziella

    2013-08-06

    Anthocyanins are a group of common phenolic compounds in plants. They are mainly detected in flowers and fruits, are believed to play different important roles such as in the attraction of animals and seed dispersal, and also in the increase of the antioxidant response in tissues directly or indirectly affected by biotic or abiotic stress factors. As a major group of secondary metabolites in plants commonly consumed as food, they are of importance in both the food industry and human nutrition. It is known that arbuscular mycorrhizal (AM) fungi can influence the plant secondary metabolic pathways such as the synthesis of essential oils in aromatic plants, of secondary metabolites in roots, and increase flavonoid concentration. Plant Growth-Promoting Bacteria (PGPB) are able to increase plant growth, improving plant nutrition and supporting plant development under natural or stressed conditions. Various studies confirmed that a number of bacterial species living on and inside the root system are beneficial for plant growth, yield and crop quality. In this work it is shown that inoculation with AM fungi and/or with selected and tested Pseudomonas strains, under conditions of reduced fertilization, increases anthocyanin concentration in the fruits of strawberry.

  18. Organic and mineral fertilization, respectively, increase and decrease the development of external mycelium of arbuscular mycorrhizal fungi in a long-term field experiment.

    PubMed

    Gryndler, M; Larsen, J; Hrselová, H; Rezácová, V; Gryndlerová, H; Kubát, J

    2006-05-01

    Effects of long-term mineral fertilization and manuring on the biomass of arbuscular mycorrhizal fungi (AMF) were studied in a field experiment. Mineral fertilization reduced the growth of AMF, as estimated using both measurements of hyphal length and the signature fatty acid 16:1omega5, whereas manuring alone increased the growth of AMF. The results of AMF root colonization followed the same pattern as AMF hyphal length in soil samples, but not AMF spore densities, which increased with increasing mineral and organic fertilization. AMF spore counts and concentration of 16:1omega5 in soil did not correlate positively, suggesting that a significant portion of spores found in soil samples was dead. AMF hyphal length was not correlated with whole cell fatty acid (WCFA) 18:2omega6,9 levels, a biomarker of saprotrophic fungi, indicating that visual measurements of the AMF mycelium were not distorted by erroneous involvement of hyphae of saprotrophs. Our observations indicate that the measurement of WCFAs in soil is a useful research tool for providing information in the characterization of soil microflora.

  19. Arbuscular mycorrhizal fungi and plant growth-promoting pseudomonads increases anthocyanin concentration in strawberry fruits (Fragaria x ananassa var. Selva) in conditions of reduced fertilization.

    PubMed

    Lingua, Guido; Bona, Elisa; Manassero, Paola; Marsano, Francesco; Todeschini, Valeria; Cantamessa, Simone; Copetta, Andrea; D'Agostino, Giovanni; Gamalero, Elisa; Berta, Graziella

    2013-01-01

    Anthocyanins are a group of common phenolic compounds in plants. They are mainly detected in flowers and fruits, are believed to play different important roles such as in the attraction of animals and seed dispersal, and also in the increase of the antioxidant response in tissues directly or indirectly affected by biotic or abiotic stress factors. As a major group of secondary metabolites in plants commonly consumed as food, they are of importance in both the food industry and human nutrition. It is known that arbuscular mycorrhizal (AM) fungi can influence the plant secondary metabolic pathways such as the synthesis of essential oils in aromatic plants, of secondary metabolites in roots, and increase flavonoid concentration. Plant Growth-Promoting Bacteria (PGPB) are able to increase plant growth, improving plant nutrition and supporting plant development under natural or stressed conditions. Various studies confirmed that a number of bacterial species living on and inside the root system are beneficial for plant growth, yield and crop quality. In this work it is shown that inoculation with AM fungi and/or with selected and tested Pseudomonas strains, under conditions of reduced fertilization, increases anthocyanin concentration in the fruits of strawberry. PMID:23924942

  20. Arbuscular Mycorrhizal Fungi and Plant Growth-Promoting Pseudomonads Increases Anthocyanin Concentration in Strawberry Fruits (Fragaria x ananassa var. Selva) in Conditions of Reduced Fertilization

    PubMed Central

    Lingua, Guido; Bona, Elisa; Manassero, Paola; Marsano, Francesco; Todeschini, Valeria; Cantamessa, Simone; Copetta, Andrea; D’Agostino, Giovanni; Gamalero, Elisa; Berta, Graziella

    2013-01-01

    Anthocyanins are a group of common phenolic compounds in plants. They are mainly detected in flowers and fruits, are believed to play different important roles such as in the attraction of animals and seed dispersal, and also in the increase of the antioxidant response in tissues directly or indirectly affected by biotic or abiotic stress factors. As a major group of secondary metabolites in plants commonly consumed as food, they are of importance in both the food industry and human nutrition. It is known that arbuscular mycorrhizal (AM) fungi can influence the plant secondary metabolic pathways such as the synthesis of essential oils in aromatic plants, of secondary metabolites in roots, and increase flavonoid concentration. Plant Growth-Promoting Bacteria (PGPB) are able to increase plant growth, improving plant nutrition and supporting plant development under natural or stressed conditions. Various studies confirmed that a number of bacterial species living on and inside the root system are beneficial for plant growth, yield and crop quality. In this work it is shown that inoculation with AM fungi and/or with selected and tested Pseudomonas strains, under conditions of reduced fertilization, increases anthocyanin concentration in the fruits of strawberry. PMID:23924942

  1. Combining nested PCR and restriction digest of the internal transcribed spacer region to characterize arbuscular mycorrhizal fungi on roots from the field.

    PubMed

    Renker, Carsten; Heinrichs, Jochen; Kaldorf, Michael; Buscot, François

    2003-08-01

    Identification of arbuscular mycorrhizal fungi (AMF) on roots is almost impossible with morphological methods and, due to the presence of contaminating fungi, it is also difficult with molecular biological techniques. To allow broad investigation of the population structure of AMF in the field, we have established a new method to selectively amplify the internal transcribed spacer (ITS) region of most AMF with a unique primer set. Based on available sequences of the rDNA, one primer pair specific for AMF and a few other fungal groups was designed and combined in a nested PCR with the already established primer pair ITS5/ITS4. Amplification from contaminating organisms was reduced by an AluI restriction after the first reaction of the nested PCR. The method was assessed at five different field sites representing different types of habitats. Members of all major groups within the Glomeromycota (except Archaeosporaceae) were detected at the different sites. Gigasporaceae also proved detectable with the method based on cultivated strains. PMID:12938031

  2. Increased diversity of arbuscular mycorrhizal fungi in a long-term field experiment via application of organic amendments to a semiarid degraded soil.

    PubMed

    del Mar Alguacil, Maria; Díaz-Pereira, Elvira; Caravaca, Fuensanta; Fernández, Diego A; Roldán, Antonio

    2009-07-01

    In this study, we tested whether communities of arbuscular mycorrhizal (AM) fungi associated with roots of plant species forming vegetative cover as well as some soil parameters (amounts of phosphatase and glomalin-related soil protein, microbial biomass C and N concentrations, amount of P available, and aggregate stability) were affected by different amounts (control, 6.5 kg m(-2), 13.0 kg m(-2), 19.5 kg m(-2), and 26.0 kg m(-2)) of an urban refuse (UR) 19 years after its application to a highly eroded, semiarid soil. The AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, single-stranded conformation polymorphism analysis, sequencing, and phylogenetic analyses. One hundred sixteen SSU rRNA sequences were analyzed, and nine AM fungal types belonging to Glomus groups A and B were identified: three of them were present in all the plots that had received UR, and six appeared to be specific to certain amendment doses. The community of AM fungi was more diverse after the application of the different amounts of UR. The values of all the soil parameters analyzed increased proportionally with the dose of amendment applied. In conclusion, the application of organic wastes enhanced soil microbial activities and aggregation, and the AM fungal diversity increased, particularly when a moderate dose of UR (13.0 kg m(-2)) was applied.

  3. Inoculation of tomato seedlings with Trichoderma Harzianum and Arbuscular Mycorrhizal Fungi and their effect on growth and control of wilt in tomato seedlings.

    PubMed

    Mwangi, Margaret W; Monda, Ethel O; Okoth, Sheila A; Jefwa, Joyce M

    2011-04-01

    A green house study was conducted to investigate the ability of an isolate of Trichoderma harzianum (P52) and arbuscular mycorrhizal fungi (AMF) in enhancing growth and control of a wilt pathogen caused by Fusarium oxysporum f. sp. lycopersici in tomato seedlings. The plants were grown in plastic pots filled with sterilized soils. There were four treatments applied as follows; P52, AMF, AMF + P52 and a control. A completely randomized design was used and growth measurements and disease assessment taken after 3, 6 and 9 weeks. Treatments that significantly (P < 0.05) enhanced heights and root dry weights were P52, AMF and a treatment with a combination of both P52 and AMF when compared the control. The treatment with both P52 and AMF significantly (P < 0.05) enhanced all growth parameters (heights; shoot and root dry weight) investigated compared to the control. Disease severity was generally lower in tomato plants grown with isolate P52 and AMF fungi either individually or when combined together, though the effect was not statistically significant (P≥ 0.05). A treatment combination of P52 + AMF had less trend of severity as compared to each individual fungus. T. harzianum and AMF can be used to enhance growth in tomato seedlings.

  4. The effects of arbuscular mycorrhizal fungi on sex-specific responses to Pb pollution in Populus cathayana.

    PubMed

    Chen, Lianghua; Hu, Xiangwei; Yang, Wanqin; Xu, Zhenfeng; Zhang, Danju; Gao, Shun

    2015-03-01

    Using fast-growing trees to remediate soils polluted by heavy metals (HMs) has received increasingly more attention, especially for recalcitrant Pb, as one of the most seriously toxic HMs. However, little is known about the responses of plants to a diffused level of Pb pollution, and a more combined phytoremediation technique is needed to explore. In this study, an arbuscular mycorrhizal fungus (AMF), i.e., Funneliformis mosseae, isolated from Populus euphratica distributed in a tailing of Pb/Zn ore, was introduced to investigate its effects on sex-specific responses of P. cathayana in morphology, physiology, and Pb phytoremediation capacity, when exposed to a diffused level of Pb pollution (100mg Pb(2+) kg(-1) dry soil). Symbiosis with exotic AMF did not significantly affect growth of both sexes and biomass allocation. However, when inoculated with AMF, both sexes absorbed more P, but not N in the roots, especially when exposed to the exogenous addition of Pb. The improvement of nutrient status under such conditions might be associated with a further increase in activity of antioxidant enzymes (particularly for superoxide dismutase (SOD) and catalase (CAT)), and the mitigation of oxidation stress induced by excessive reactive oxygen species (ROS). We also observed that exotic AMF could promote the uptake and accumulation of Pb in roots of females, but not in that of males. Therefore, under this diffused pollution level, the infected females might be more suitable for remediation of this metal than infected males, due to the higher capacity of HM accumulation without obvious negative effects on growth and physiological traits. Moreover, field surveys are needed to testify our experimental results, due to diversity of soil microbial community and complexities of their interaction.

  5. Effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) inoculation on oats in saline-alkali soil contaminated by petroleum to enhance phytoremediation.

    PubMed

    Xun, Feifei; Xie, Baoming; Liu, Shasha; Guo, Changhong

    2015-01-01

    To investigate the effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on phytoremediation in saline-alkali soil contaminated by petroleum, saline-alkali soil samples were artificially mixed with different amount of oil, 5 and 10 g/kg, respectively. Pot experiments with oat plants (Avena sativa) were conducted under greenhouse condition for 60 days. Plant biomass, physiological parameters in leaves, soil enzymes, and degradation rate of total petroleum hydrocarbon were measured. The result demonstrated that petroleum inhibited the growth of the plant; however, inoculation with PGPR in combination with AMF resulted in an increase in dry weight and stem height compared with noninoculated controls. Petroleum stress increased the accumulation of malondialdehyde (MDA) and free proline and the activities of the antioxidant enzyme such as superoxide dismutase, catalase, and peroxidase. Application of PGPR and AMF augmented the activities of three enzymes compared to their respective uninoculated controls, but decreased the MDA and free proline contents, indicating that PGPR and AMF could make the plants more tolerant to harmful hydrocarbon contaminants. It also improved the soil quality by increasing the activities of soil enzyme such as urease, sucrase, and dehydrogenase. In addition, the degradation rate of total petroleum hydrocarbon during treatment with PGPR and AMF in moderately contaminated soil reached a maximum of 49.73%. Therefore, we concluded the plants treated with a combination of PGPR and AMF had a high potential to contribute to remediation of saline-alkali soil contaminated with petroleum.

  6. Community Structure of Arbuscular Mycorrhizal Fungi in Rhizospheric Soil of a Transgenic High-Methionine Soybean and a Near Isogenic Variety

    PubMed Central

    Liang, Jingang; Meng, Fang; Sun, Shi; Wu, Cunxiang; Wu, Haiying; Zhang, Mingrong; Zhang, Haifeng; Zheng, Xiaobo; Song, Xinyuan; Zhang, Zhengguang

    2015-01-01

    The use of transgenic plants in agriculture provides many economic benefits, but it also raises concerns over the potential impact of transgenic plants on the environment. We here examined the impact of transgenic high-methionine soybean ZD91 on the arbuscular mycorrhizal (AM) fungal community structure in rhizosphere soil. Our investigations based on clone libraries were conducted in field trials at four growth stages of the crops each year from 2012 to 2013. A total of 155 operational taxonomic units (OTUs) of AM fungi were identified based on the sequences of small subunit ribosomal RNA (SSU rRNA) genes. There were no significant differences found in AM fungal diversity in rhizosphere soil during the same growth stage between transgenic soybean ZD91 and its non-transgenic parental soybean ZD. In addition, plant growth stage and year had the strongest effect on the AM fungal community structure while the genetically modified (GM) trait studied was the least explanatory factor. In conclusion, we found no indication that transgenic soybean ZD91 cultivation poses a risk for AM fungal communities in agricultural soils. PMID:26658560

  7. Mating Type Gene Homologues and Putative Sex Pheromone-Sensing Pathway in Arbuscular Mycorrhizal Fungi, a Presumably Asexual Plant Root Symbiont

    PubMed Central

    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. PMID:24260466

  8. Community Structure of Arbuscular Mycorrhizal Fungi in Rhizospheric Soil of a Transgenic High-Methionine Soybean and a Near Isogenic Variety.

    PubMed

    Liang, Jingang; Meng, Fang; Sun, Shi; Wu, Cunxiang; Wu, Haiying; Zhang, Mingrong; Zhang, Haifeng; Zheng, Xiaobo; Song, Xinyuan; Zhang, Zhengguang

    2015-01-01

    The use of transgenic plants in agriculture provides many economic benefits, but it also raises concerns over the potential impact of transgenic plants on the environment. We here examined the impact of transgenic high-methionine soybean ZD91 on the arbuscular mycorrhizal (AM) fungal community structure in rhizosphere soil. Our investigations based on clone libraries were conducted in field trials at four growth stages of the crops each year from 2012 to 2013. A total of 155 operational taxonomic units (OTUs) of AM fungi were identified based on the sequences of small subunit ribosomal RNA (SSU rRNA) genes. There were no significant differences found in AM fungal diversity in rhizosphere soil during the same growth stage between transgenic soybean ZD91 and its non-transgenic parental soybean ZD. In addition, plant growth stage and year had the strongest effect on the AM fungal community structure while the genetically modified (GM) trait studied was the least explanatory factor. In conclusion, we found no indication that transgenic soybean ZD91 cultivation poses a risk for AM fungal communities in agricultural soils. PMID:26658560

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

    PubMed

    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.

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

    PubMed

    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.

  11. Influence of arbuscular mycorrhizal fungi (AMF) on zinc biogeochemistry in the rhizosphere of Lindenbergia philippensis growing in zinc-contaminated sediment.

    PubMed

    Kangwankraiphaisan, Thanchanok; Suntornvongsagul, Kallaya; Sihanonth, Prakitsin; Klysubun, Wantana; Gadd, Geoffrey Michael

    2013-06-01

    The association of arbuscular mycorrhizal fungi (AMF) with the roots of Lindenbergia philippensis (Cham.) Benth., sampled from a Zn-contaminated settling pond at a zinc smelter, significantly enhanced Zn accumulation (72,540 ± 5,092 mg kg⁻¹ dry weight) in rhizosphere sediment amended with 1,000 mg L⁻¹ of Zn sulfate solution compared to fungicide-treatments that suppressed AMF colonization. This can be explained by a significant proportion of Zn being found in rectangular crystals that were associated with the root mucilaginous sheath. Despite this, all treatments maintained the same Zn coordination geometry in both Zn oxidation state and the coordinated neighbouring atoms. X-ray absorption spectroscopy (XAS) showed a Zn(II) oxidation state as a core atom and associated with six oxygen atoms symmetrically arranged in an octahedral coordination and coordinated with sulfur. The results may indicate a role for AMF in enhancing Zn immobilization in the rhizosphere of indigenous plants that successfully colonize Zn mining and smelting disposal sites.

  12. Induction of Osmoregulation and Modulation of Salt Stress in Acacia gerrardii Benth. by Arbuscular Mycorrhizal Fungi and Bacillus subtilis (BERA 71)

    PubMed Central

    Hashem, Abeer; Alqarawi, A. A.; Al-Huqail, A. A.; Shah, M. A.

    2016-01-01

    The role of soil microbiota in plant stress management, though speculated a lot, is still far from being completely understood. We conducted a greenhouse experiment to examine synergistic impact of plant growth promoting rhizobacterium, Bacillus subtilis (BERA 71), and arbuscular mycorrhizal fungi (AMF) (Claroideoglomus etunicatum; Rhizophagus intraradices; and Funneliformis mosseae) to induce acquired systemic resistance in Talh tree (Acacia gerrardii Benth.) against adverse impact of salt stress. Compared to the control, the BERA 71 treatment significantly enhanced root colonization intensity by AMF, in both presence and absence of salt. We also found positive synergistic interaction between B. subtilis and AMF vis-a-vis improvement in the nutritional value in terms of increase in total lipids, phenols, and fiber content. The AMF and BERA 71 inoculated plants showed increased content of osmoprotectants such as glycine, betaine, and proline, though lipid peroxidation was reduced probably as a mechanism of salt tolerance. Furthermore, the application of bioinoculants to Talh tree turned out to be potentially beneficial in ameliorating the deleterious impact of salinity on plant metabolism, probably by modulating the osmoregulatory system (glycine betaine, proline, and phenols) and antioxidant enzymes system (SOD, CAT, POD, GR, APX, DHAR, MDAHR, and GSNOR). PMID:27597969

  13. [Community diversity of bacteria and arbuscular mycorrhizal fungi in the rhizosphere of eight plants in Liudaogou watershed on the Loess Plateau China].

    PubMed

    Feng, Ye; Tang, Ming; Chen, Hui; Cong, Wei

    2012-01-01

    Terminal restriction fragment length polymorphism (T-RFLP) was used to examine the community diversity of bacteria and arbuscular mycorrhizal fungi (AMF) and their interrelation in the rhizosphere of 8 plants in the Liudaogou watershed in Shenmu County. The objective was to obtain diversity indices and provide theoretical basis for ecological restoration. Results showed significant variations in the species and abundances of rhizospheric bacteria and AMF associated with 8 plants. Among these, the Shannon diversity index of rhizospheric bacteria was the highest for Robinia pseudoacacia (4.01) and the lowest for Salix babylonica (2.18), whereas the Shannon diversity index of rhizospheric AMF was the highest for Populus simonii (2.07) and the lowest for Hippophae rhamnoides (1.21). Cluster analysis and redundancy analysis indicated a significant difference in associated microbial community structure, while the similarity among community diversity of rhizospheric bacteria and AMF associated with specific plants was also found. There was a significant correlation between diversity indices of bacteria and AMF (P < 0.01). Associated microbial community diversity was influenced primarily by organic matter and total nitrogen content. Our work demonstrated strong impacts of plant species and rhizospheric environment on associated microbial community structure. Due to the high diversity indices of rhizospheric bacteria and AMF, R. pseudoacacia was considered to be a pioneer plant species for vegetation restoration in the Liudaogou watershed.

  14. Evidence of Differences between the Communities of Arbuscular Mycorrhizal Fungi Colonizing Galls and Roots of Prunus persica Infected by the Root-Knot Nematode Meloidogyne incognita▿

    PubMed Central

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

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) play important roles as plant protection agents, reducing or suppressing nematode colonization. However, it has never been investigated whether the galls produced in roots by nematode infection are colonized by AMF. This study tested whether galls produced by Meloidogyne incognita infection in Prunus persica roots are colonized by AMF. We also determined the changes in AMF composition and biodiversity mediated by infection with this root-knot nematode. DNA from galls and roots of plants infected by M. incognita and from roots of noninfected plants was extracted, amplified, cloned, and sequenced using AMF-specific primers. Phylogenetic analysis using the small-subunit (SSU) ribosomal DNA (rDNA) data set revealed 22 different AMF sequence types (17 Glomus sequence types, 3 Paraglomus sequence types, 1 Scutellospora sequence type, and 1 Acaulospora sequence type). The highest AMF diversity was found in uninfected roots, followed by infected roots and galls. This study indicates that the galls produced in P. persica roots due to infection with M. incognita were colonized extensively by a community of AMF, belonging to the families Paraglomeraceae and Glomeraceae, that was different from the community detected in roots. Although the function of the AMF in the galls is still unknown, we hypothesize that they act as protection agents against opportunistic pathogens. PMID:21984233

  15. Arbuscular Mycorrhizal Fungi Community Structure, Abundance and Species Richness Changes in Soil by Different Levels of Heavy Metal and Metalloid Concentration

    PubMed Central

    Krishnamoorthy, Ramasamy; Kim, Chang-Gi; Subramanian, Parthiban; Kim, Ki-Yoon; Selvakumar, Gopal; Sa, Tong-Min

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) play major roles in ecosystem functioning such as carbon sequestration, nutrient cycling, and plant growth promotion. It is important to know how this ecologically important soil microbial player is affected by soil abiotic factors particularly heavy metal and metalloid (HMM). The objective of this study was to understand the impact of soil HMM concentration on AMF abundance and community structure in the contaminated sites of South Korea. Soil samples were collected from the vicinity of an abandoned smelter and the samples were subjected to three complementary methods such as spore morphology, terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Spore density was found to be significantly higher in highly contaminated soil compared to less contaminated soil. Spore morphological study revealed that Glomeraceae family was more abundant followed by Acaulosporaceae and Gigasporaceae in the vicinity of the smelter. T-RFLP and DGGE analysis confirmed the dominance of Funneliformis mosseae and Rhizophagus intraradices in all the study sites. Claroideoglomus claroideum, Funneliformis caledonium, Rhizophagus clarus and Funneliformis constrictum were found to be sensitive to high concentration of soil HMM. Richness and diversity of Glomeraceae family increased with significant increase in soil arsenic, cadmium and zinc concentrations. Our results revealed that the soil HMM has a vital impact on AMF community structure, especially with Glomeraceae family abundance, richness and diversity. PMID:26035444

  16. Induction of Osmoregulation and Modulation of Salt Stress in Acacia gerrardii Benth. by Arbuscular Mycorrhizal Fungi and Bacillus subtilis (BERA 71)

    PubMed Central

    Hashem, Abeer; Alqarawi, A. A.; Al-Huqail, A. A.; Shah, M. A.

    2016-01-01

    The role of soil microbiota in plant stress management, though speculated a lot, is still far from being completely understood. We conducted a greenhouse experiment to examine synergistic impact of plant growth promoting rhizobacterium, Bacillus subtilis (BERA 71), and arbuscular mycorrhizal fungi (AMF) (Claroideoglomus etunicatum; Rhizophagus intraradices; and Funneliformis mosseae) to induce acquired systemic resistance in Talh tree (Acacia gerrardii Benth.) against adverse impact of salt stress. Compared to the control, the BERA 71 treatment significantly enhanced root colonization intensity by AMF, in both presence and absence of salt. We also found positive synergistic interaction between B. subtilis and AMF vis-a-vis improvement in the nutritional value in terms of increase in total lipids, phenols, and fiber content. The AMF and BERA 71 inoculated plants showed increased content of osmoprotectants such as glycine, betaine, and proline, though lipid peroxidation was reduced probably as a mechanism of salt tolerance. Furthermore, the application of bioinoculants to Talh tree turned out to be potentially beneficial in ameliorating the deleterious impact of salinity on plant metabolism, probably by modulating the osmoregulatory system (glycine betaine, proline, and phenols) and antioxidant enzymes system (SOD, CAT, POD, GR, APX, DHAR, MDAHR, and GSNOR).

  17. Arbuscular mycorrhizal fungi community structure, abundance and species richness changes in soil by different levels of heavy metal and metalloid concentration.

    PubMed

    Krishnamoorthy, Ramasamy; Kim, Chang-Gi; Subramanian, Parthiban; Kim, Ki-Yoon; Selvakumar, Gopal; Sa, Tong-Min

    2015-01-01

    Arbuscular Mycorrhizal Fungi (AMF) play major roles in ecosystem functioning such as carbon sequestration, nutrient cycling, and plant growth promotion. It is important to know how this ecologically important soil microbial player is affected by soil abiotic factors particularly heavy metal and metalloid (HMM). The objective of this study was to understand the impact of soil HMM concentration on AMF abundance and community structure in the contaminated sites of South Korea. Soil samples were collected from the vicinity of an abandoned smelter and the samples were subjected to three complementary methods such as spore morphology, terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Spore density was found to be significantly higher in highly contaminated soil compared to less contaminated soil. Spore morphological study revealed that Glomeraceae family was more abundant followed by Acaulosporaceae and Gigasporaceae in the vicinity of the smelter. T-RFLP and DGGE analysis confirmed the dominance of Funneliformis mosseae and Rhizophagus intraradices in all the study sites. Claroideoglomus claroideum, Funneliformis caledonium, Rhizophagus clarus and Funneliformis constrictum were found to be sensitive to high concentration of soil HMM. Richness and diversity of Glomeraceae family increased with significant increase in soil arsenic, cadmium and zinc concentrations. Our results revealed that the soil HMM has a vital impact on AMF community structure, especially with Glomeraceae family abundance, richness and diversity. PMID:26035444

  18. The largest subunit of RNA polymerase II as a new marker gene to study assemblages of arbuscular mycorrhizal fungi in the field.

    PubMed

    Stockinger, Herbert; Peyret-Guzzon, Marine; Koegel, Sally; Bouffaud, Marie-Lara; Redecker, Dirk

    2014-01-01

    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.

  19. Arbuscular mycorrhizal fungi enhance fruit growth and quality of chile ancho (Capsicum annuum L. cv San Luis) plants exposed to drought.

    PubMed

    Mena-Violante, Hortencia G; Ocampo-Jiménez, Omar; Dendooven, Luc; Martínez-Soto, Gerardo; González-Castañeda, Jaquelina; Davies, Fred T; Olalde-Portugal, Víctor

    2006-06-01

    The effect of arbuscular mycorrhizal fungi (AMF) and drought on fruit quality was evaluated in chile ancho (Capsicum annuum L. cv San Luis). AMF treatments were (1) Glomus fasciculatum (AMFG), (2) a fungal species consortium from the forest "Los Tuxtla" in Mexico (AMFT), (3) a fungal species consortium from the Sonorian desert in Mexico (AMFD), and (4) a noninoculated control (NAMF). Plants were exposed to a 26-day drought cycle. Fruit quality was determined by measuring size (length, width, and pedicel length), color, chlorophyll, and carotenoid concentration. Under nondrought conditions, AMFG produced fruits that were 13% wider and 15% longer than the NAMF treatment. Under nondrought conditions, fruit fresh weight was 25% greater in the AMFG treatment compared to the NAMF. Under drought, fruits in the AMFT and AMFD treatments showed fresh weights similar to those in the NAMF treatment not subjected to drought. Fruits of the AMFG treatment subjected to drought showed the same color intensity and chlorophyll content as those of the nondroughted NAMF treatment and carotenoid content increased 1.4 times compared to that in the NAMF not exposed to drought. It is interesting to note that fruits in the AMFD treatment subjected to drought and the NAMF treatment not exposed to drought reached the same size. AMFD treatment increased the concentration of carotenes (1.4 times) under nondrought conditions and the concentration of xanthophylls (1.5 times) under drought when compared to the nondroughted NAMF treatment.

  20. Differential effects of abiotic factors and host plant traits on diversity and community composition of root-colonizing arbuscular mycorrhizal fungi in a salt-stressed ecosystem.

    PubMed

    Guo, Xiaohong; Gong, Jun

    2014-02-01

    Arbuscular mycorrhizal fungi (AMF) were investigated in roots of 18 host plant species in a salinized south coastal plain of Laizhou Bay, China. From 18 clone libraries of 18S rRNA genes, all of the 22 AMF phylotypes were identified into Glomus, of which 18 and 4 were classified in group A and B in the phylogenetic tree, respectively. The phylotypes related to morphologically defined Glomus species occurred generally in soil with higher salinity. AMF phylotype richness, Shannon index, and evenness were not significantly different between root samples from halophytes vs. non-halophytes, invades vs. natives, or annuals vs. perennials. However, AMF diversity estimates frequently differed along the saline gradient or among locations, but not among pH gradients. Moreover, UniFrac tests showed that both plant traits (salt tolerance, life style or origin) and abiotic factors (salinity, pH, or location) significantly affected the community composition of AMF colonizers. Redundancy and variation partitioning analyses revealed that soil salinity and pH, which respectively explained 6.9 and 4.2 % of the variation, were the most influential abiotic variables in shaping the AMF community structure. The presented data indicate that salt tolerance, life style, and origin traits of host species may not significantly affect the AMF diversity in roots, but do influence the community composition in this salinized ecosystem. The findings also highlight the importance of soil salinity and pH in driving the distribution of AMF in plant and soil systems.

  1. Arbuscular mycorrhizal fungi contribute to phosphorus uptake by wheat grown in a phosphorus-fixing soil even in the absence of positive growth responses.

    PubMed

    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.

  2. Community Structure of Arbuscular Mycorrhizal Fungi in Rhizospheric Soil of a Transgenic High-Methionine Soybean and a Near Isogenic Variety.

    PubMed

    Liang, Jingang; Meng, Fang; Sun, Shi; Wu, Cunxiang; Wu, Haiying; Zhang, Mingrong; Zhang, Haifeng; Zheng, Xiaobo; Song, Xinyuan; Zhang, Zhengguang

    2015-01-01

    The use of transgenic plants in agriculture provides many economic benefits, but it also raises concerns over the potential impact of transgenic plants on the environment. We here examined the impact of transgenic high-methionine soybean ZD91 on the arbuscular mycorrhizal (AM) fungal community structure in rhizosphere soil. Our investigations based on clone libraries were conducted in field trials at four growth stages of the crops each year from 2012 to 2013. A total of 155 operational taxonomic units (OTUs) of AM fungi were identified based on the sequences of small subunit ribosomal RNA (SSU rRNA) genes. There were no significant differences found in AM fungal diversity in rhizosphere soil during the same growth stage between transgenic soybean ZD91 and its non-transgenic parental soybean ZD. In addition, plant growth stage and year had the strongest effect on the AM fungal community structure while the genetically modified (GM) trait studied was the least explanatory factor. In conclusion, we found no indication that transgenic soybean ZD91 cultivation poses a risk for AM fungal communities in agricultural soils.

  3. Root colonization and spore abundance of arbuscular mycorrhizal fungi in distinct successional stages from an Atlantic rainforest biome in southern Brazil.

    PubMed

    Zangaro, Waldemar; Rostirola, Leila Vergal; de Souza, Priscila Bochi; de Almeida Alves, Ricardo; Lescano, Luiz Eduardo Azevedo Marques; Rondina, Artur Berbel Lírio; Nogueira, Marco Antonio; Carrenho, Rosilaine

    2013-04-01

    The influence of plant functional groups and moderate seasonality on arbuscular mycorrhizal (AM) fungal status (root colonization and spore density) was investigated during 13 consecutive months in a chronosequence of succession in southern Brazil, consisting of grassland field, scrub vegetation, secondary forest and mature forest, in a region of transition from tropical to subtropical zones. AM root colonization and spore density decreased with advancing succession and were highest in early successional sites with grassland and scrub vegetation, intermediary in the secondary forest and lowest in the mature forest. They were little influenced by soil properties, but were sufficiently influenced by the fine root nutrient status and fine root traits among different functional plant groups. AM root colonization and spore density were higher during the favourable plant growth season (spring and summer) than during the less favourable plant growth season (autumn and winter). Spore density displayed significant seasonal variation at all sites, whilst root colonization displayed significant seasonal variation in grassland, scrub and secondary forest, but not in mature forest. The data suggest that (1) different plant functional groups display different relationships with AM fungi, influencing their abundance differentially; (2) plant species from early successional phases are more susceptible to AM root colonization and maintain higher AM sporulation than late successional species; (3) fine root traits and nutrient status influence these AM fungal attributes; and (4) higher AM spore production and root colonization is associated with the season of higher light incidence and temperature, abundant water in soil and higher plant metabolic activity.

  4. Application of arbuscular mycorrhizal fungi with Pseudomonas aeruginosa UPMP3 reduces the development of Ganoderma basal stem rot disease in oil palm seedlings.

    PubMed

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

    2015-07-01

    The effect of arbuscular mycorrhizal fungi (AMF) in combination with endophytic bacteria (EB) in reducing development of basal stem rot (BSR) disease in oil palm (Elaeis guineensis) was investigated. BSR caused by Ganoderma boninense leads to devastating economic loss and the oil palm industry is struggling to control the disease. The application of two AMF with two EB as biocontrol agents was assessed in the nursery and subsequently, repeated in the field using bait seedlings. Seedlings pre-inoculated with a combination of Glomus intraradices UT126, Glomus clarum BR152B and Pseudomonas aeruginosa UPMP3 significantly reduced disease development measured as the area under disease progression curve (AUDPC) and the epidemic rate (R L) of disease in the nursery. A 20-month field trial using similar treatments evaluated disease development in bait seedlings based on the rotting area/advancement assessed in cross-sections of the seedling base. Data show that application of Glomus intraradices UT126 singly reduced disease development of BSR, but that combination of the two AMF with P. aeruginosa UPMP3 significantly improved biocontrol efficacy in both nursery and fields reducing BSR disease to 57 and 80%, respectively. The successful use of bait seedlings in the natural environment to study BSR development represents a promising alternative to nursery trial testing in the field with shorter temporal assessment.

  5. Diversity of the small subunit ribosomal RNA gene of the arbuscular mycorrhizal fungi colonizing Clintonia borealis from a mixed-wood boreal forest.

    PubMed

    DeBellis, Tonia; Widden, Paul

    2006-11-01

    Arbuscular mycorrhizal fungi (AMF) communities in Clintonia borealis roots from a boreal mixed forests in northwestern Québec were investigated. Roots were sampled from 100 m2 plots whose overstory was dominated by either trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), or mixed white spruce (Picea glauca (Moench) Voss) and balsam fir (Abies balsamea (L.) Mill.). Part of the 18S ribosomal gene of the AMF was amplified and the resulting PCR products