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1.
The arbuscular mycorrhizal fungus Rhizophagus intraradices and other microbial groups affect plant species in a copper-contaminated post-mining soil.
Ardestani, MM, Frouz, J
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2020;:126594
Abstract
BACKGROUND AND AIM Arbuscular mycorrhizal fungi (AMF) have an important role in plant-microbe interactions. But, there are few studies in which the combined effect of AMF with a stress factor, such as the presence of a metal, on plant species were assessed. This study investigated the effect of arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices and other soil microbial groups in the presence of copper on three plant species in a microcosm experiment. METHODS Two grass species Poa compressa and Festuca rubra and one herb species Centaurea jacea were selected as model plants in a pot-design test in which soils were artificially contaminated with copper. Treatments were bacteria (control), saprophytic fungi, protists, and a combined treatment of saprophytic fungi and protists, all in the presence or absence of the AM fungal species. After sixty days, plants were harvested and the biomass of grass and herb species and microbial respiration were measured. RESULTS The results showed almost equal above- and belowground plant biomass and microbial respiration in the treatments in the presence or absence of R. intraradices. The herb species C. jecea responded significantly to the soil inoculation with AM fungus, while grass species showed inconsistent patterns. Significant effect of AMF and copper and their interactions was observed on plant biomass when comparing contaminated vs. non-contaminated soils. CONCLUSION Strong effect of AMF on the biomass of herb species and slight changes in plant growth with the presence of this fungal species in copper-spiked test soils indicates the importance of mycorrhizal fungi compared to other soil microorganisms in our experimental microcosms.
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2.
How mycorrhizal associations drive plant population and community biology.
Tedersoo, L, Bahram, M, Zobel, M
Science (New York, N.Y.). 2020;(6480)
Abstract
Mycorrhizal fungi provide plants with a range of benefits, including mineral nutrients and protection from stress and pathogens. Here we synthesize current information about how the presence and type of mycorrhizal association affect plant communities. We argue that mycorrhizal fungi regulate seedling establishment and species coexistence through stabilizing and equalizing mechanisms such as soil nutrient partitioning, feedback to soil antagonists, differential mycorrhizal benefits, and nutrient trade. Mycorrhizal fungi have strong effects on plant population and community biology, with mycorrhizal type-specific effects on seed dispersal, seedling establishment, and soil niche differentiation, as well as interspecific and intraspecific competition and hence plant diversity.
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3.
Plant health status effects on arbuscular mycorrhizal fungi associated with Lavandula angustifolia and Lavandula intermedia infected by Phytoplasma in France.
Binet, MN, Marchal, C, Lipuma, J, Geremia, RA, Bagarri, O, Candaele, B, Fraty, D, David, B, Perigon, S, Barbreau, V, et al
Scientific reports. 2020;(1):20305
Abstract
We investigated root communities of arbuscular mycorrhizal fungi (AMF) in relation to lavender (Lavandula angustifolia) and lavandin (Lavandula intermedia) health status from organic and conventional fields affected by Phytoplasma infection. The intensity of root mycorrhizal colonization was significantly different between diseased and healthy plants and was higher in the latter regardless of agricultural practice. This difference was more pronounced in lavender. The root AMF diversity was influenced by the plant health status solely in lavender and only under the conventional practice resulting in an increase in the AMF abundance and richness. The plant health status did not influence the distribution of root AMF communities in lavandin unlike its strong impact in lavender in both agricultural practices. Finally, among the most abundant molecular operational taxonomic units (MOTUs), four different MOTUs for each plant species were significantly abundant in the roots of healthy lavender and lavandin in either agricultural practice. Our study demonstrated that the plant health status influences root colonization and can influence the diversity and distribution of root AMF communities. Its effects vary according to plant species, can be modified by agricultural practices and allow plants to establish symbiosis with specific AMF species.
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4.
Significance of Arbuscular Mycorrhizal Fungi for Acacia: A Review.
Saini, I, Himanshi, , Rani, K, Gill, N, Sandhu, K, Bisht, N, Kumar, T, Kaushik, P
Pakistan journal of biological sciences : PJBS. 2020;(10):1231-1236
Abstract
Microbes play a vital role in ecosystem stability. Here, microbes-Acacia association is discussed with particular reference to Arbuscular Mycorrhizal Fungi (AMF) which help in the establishment of crop-plants, especially in arid and semi-arid areas. The association helps to restore the structural composition of soil from the hazardous impact of agrochemicals, increase resistance against various pathogenic attack as well as several abiotic stresses. Further, a comparative account of microbes found in the rhizosphere of Acacia is illustrated. Among these, Rhizobia, Acetobacter, Bradyrhizobium, Bacillus, Pseudomonas and Trichoderma were described in detail. All these microbes can be regarded as Plant Growth Promoting Rhizospheric Microbes (PGPM), some of PGPM are Phosphate Solubilizing Microbe (PSM). Both of them help AMF for infecting mycorrhizal hyphae inside the plant cell. Overall, microbes can be used as biofertilizers along with other organic compounds, that can compensate for the nutrient's availability.
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5.
The potential of arbuscular mycorrhizal fungi in C cycling: a review.
Parihar, M, Rakshit, A, Meena, VS, Gupta, VK, Rana, K, Choudhary, M, Tiwari, G, Mishra, PK, Pattanayak, A, Bisht, JK, et al
Archives of microbiology. 2020;(7):1581-1596
Abstract
Arbuscular mycorrhizal fungi (AMF) contribute predominantly to soil organic matter by creating a sink demand for plant C and distributing to below-ground hyphal biomass. The extra-radical hyphae along with glomalin-related soil protein significantly influence the soil carbon dynamics through their larger extent and turnover period need to discuss. The role of AMF is largely overlooked in terrestrial C cycling and climate change models despite their greater involvement in net primary productivity augmentation and further accumulation of this additional photosynthetic fixed C in the soil. However, this buffering mechanism against elevated CO2 condition to sequester extra C by AMF can be described only after considering their potential interaction with other microbes and associated mineral nutrients such as nitrogen cycling. In this article, we try to review the potential of AMF in C sequestration paving the way towards a better understanding of possible AMF mechanism by which C balance between biosphere and atmosphere can be moved forward in more positive direction.
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6.
Radial water transport in arbuscular mycorrhizal maize plants under drought stress conditions is affected by indole-acetic acid (IAA) application.
Quiroga, G, Erice, G, Aroca, R, Zamarreño, ÁM, García-Mina, JM, Ruiz-Lozano, JM
Journal of plant physiology. 2020;:153115
Abstract
Drought stress is one of the most devastating abiotic stresses, compromising crop growth, reproductive success and yield. The arbuscular mycorrhizal (AM) symbiosis has been demonstrated to be beneficial in helping the plant to bear with water deficit. In plants, development and stress responses are largely regulated by a complex hormonal crosstalk. Auxins play significant roles in plant growth and development, in responses to different abiotic stresses or in the establishment and functioning of the AM symbiosis. Despite these important functions, the role of indole-3acetic acid (IAA) as a regulator of root water transport and stress response is not well understood. In this study, the effect of exogenous application of IAA on the regulation of root radial water transport in AM plants was analyzed under well-watered and drought stress conditions. Exogenous IAA application affected root hydraulic parameters, mainly osmotic root hydraulic conductivity (Lo), which was decreased in both AM and non-AM plants under water deficit conditions. Under drought, the relative apoplastic water flow was differentially regulated by IAA application in non-AM and AM plants. The effect of IAA on the internal cell component of root water conductivity suggests that aquaporins are involved in the IAA-dependent inhibition of this water pathway.
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7.
Direct and indirect influence of arbuscular mycorrhizae on enhancing metal tolerance of plants.
Janeeshma, E, Puthur, JT
Archives of microbiology. 2020;(1):1-16
Abstract
The acerbic elevation of toxic metal ions in arable lands, enhance the risk of their accumulation and biomagnification in crops as well as in humans. Phytoremediation is an eco-friendly approach to clear metal-contaminated lands by making use of metal accumulation potential of plants; which are referred to as hyperaccumulators. This phytoremediation potential can be enhanced with the symbiotic association between the root of hyperaccumulators and arbuscular mycorrhizae. Modification of root morphology, enhancement of antioxidants biosynthesis, and the increase in shoot biomass are the changes observed in plants as a result of indirect influence of arbuscular mycorrhizae. Direct influence of arbuscular mycorrhizae on enhancing metal tolerance of plants includes immobilization strategies, adsorption of metals on to the hyphal wall and glomalin exudation. Furthermore, we have discussed arbuscular mycorrhizal induced increment in the metal tolerance potential of plants through the alteration in various metabolic processes with special emphasis to the phenylpropanoid pathway.
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8.
In Vivo Metabolic Regulation of Alternative Oxidase under Nutrient Deficiency-Interaction with Arbuscular Mycorrhizal Fungi and Rhizobium Bacteria.
Ortíz, J, Sanhueza, C, Romero-Munar, A, Hidalgo-Castellanos, J, Castro, C, Bascuñán-Godoy, L, Coba de la Peña, T, López-Gómez, M, Florez-Sarasa, I, Del-Saz, NF
International journal of molecular sciences. 2020;(12)
Abstract
The interaction of the alternative oxidase (AOX) pathway with nutrient metabolism is important for understanding how respiration modulates ATP synthesis and carbon economy in plants under nutrient deficiency. Although AOX activity reduces the energy yield of respiration, this enzymatic activity is upregulated under stress conditions to maintain the functioning of primary metabolism. The in vivo metabolic regulation of AOX activity by phosphorus (P) and nitrogen (N) and during plant symbioses with Arbuscular mycorrhizal fungi (AMF) and Rhizobium bacteria is still not fully understood. We highlight several findings and open questions concerning the in vivo regulation of AOX activity and its impact on plant metabolism during P deficiency and symbiosis with AMF. We also highlight the need for the identification of which metabolic regulatory factors of AOX activity are related to N availability and nitrogen-fixing legume-rhizobia symbiosis in order to improve our understanding of N assimilation and biological nitrogen fixation.
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9.
Efficiency of two arbuscular mycorrhizal fungal inocula to improve saline stress tolerance in lettuce plants by changes of antioxidant defense mechanisms.
Santander, C, Ruiz, A, García, S, Aroca, R, Cumming, J, Cornejo, P
Journal of the science of food and agriculture. 2020;(4):1577-1587
Abstract
BACKGROUND Arbuscular mycorrhizal (AM) fungi establish symbioses with most agricultural plants and improves growth under soil stress conditions. The present study aimed to evaluate the functional contribution of 2 AM fungal inocula (a native consortium isolated from saline soils of the Atacama Desert, 'HMC', and a reference inoculum Claroideoglomus claroideum, 'Cc') on the growth and antioxidant compounds of two cultivars of lettuce (Lactuca sativa cvs. 'Grand Rapids' and 'Lollo Bionda') at increasing salt stress conditions (0, 40, and 80 mmol L-1 NaCl). At 60 days of plant growth, the symbiotic development, biomass production, lipid peroxidation, proline content, antioxidant enzymes, phenolic compound profiles and antioxidant activity were evaluated. RESULTS The 2 AM inocula differentially colonized the roots of Grand Rapids and Lollo Bionda lettuce plants. The AM symbioses increased proline synthesis and superoxide dismutase, catalase and ascorbate peroxidase activities and diminished phenolic compound synthesis and oxidative damage in lettuce, which was related positively to a higher growth of inoculated plants under salt exposure. The higher concentration of phenolic compounds induced by salinity in non-inoculated plants was associated with high oxidative stress and low fresh biomass production. CONCLUSION Modulation of salinity stress in lettuce by AM root colonization is a result of changes of antioxidant enzymatic systems that reduce oxidative damage and sustain growth. The application of AM fungi to improve crop production by means of directed inoculation with efficient AM fungal strains may enhance lettuce production on soils plagued with salinity worldwide. © 2019 Society of Chemical Industry.
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10.
A low cost alternative, using mycorrhiza and organic fertilizer, to optimize the production of foliar bioactive compounds in pomegranates.
Silva, FSB, Silva, FA
Journal of applied microbiology. 2020;(2):513-517
Abstract
AIM: To select the best combination of arbuscular mycorrhizal fungi and efficient vermicompost dose in maximizing the production of leaf metabolites in Punica granatum seedlings. METHODS AND RESULTS The experimental design was in a 3 × 3 factorial arrangement: three inoculation treatments (inoculated with Gigaspora albida, inoculated with Acaulospora longula and control not inoculated) × 3 doses of vermicompost (0, 5 and 7·5%). After 120 days of inoculation, biomolecules, plant growth parameters and mycorrhizal colonization were evaluated. The combination of 7·5% of vermicompost and A. longula was favourable to the accumulation of leaf phenols, with an increase of 116·11% in relation to the non-inoculated control. The total tannins was optimized/enhanced when G. albida and 7·5% of fertilizer were used, registering an increase of 276·71%. CONCLUSIONS The application of 7·5% of vermicompost associated with A. longula and G. albida is a low cost alternative to increase the levels of bioactive compounds in pomegranate leaves. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first published report of optimization of bioactive compound production in P. granatum by the combined use of mycorrhiza and vermicompost doses.