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1.
J Sci Food Agric ; 100(3): 1092-1098, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31667839

RESUMO

BACKGROUND: Plant-growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi have the ability to enhance the growth, fitness, and quality of various agricultural crops, including cowpea. However, field trials confirming the benefits of microbes in large-scale applications using economically viable and efficient inoculation methods are still scarce. Microbial seed coating has a great potential for large-scale agriculture through the application of reduced amounts of PGPR and AM fungi inocula. Thus, in this study, the impact of seed coating with PGPR, Pseudomonas libanensis TR1 and AM fungus, Rhizophagus irregularis (single or multiple isolates) on grain yield and nutrient content of cowpea under low-input field conditions was evaluated. RESULTS: Seed coating with P. libanensis + multiple isolates of R. irregularis (coatPMR) resulted in significant increases in shoot dry weight (76%), and in the number of pods and seeds per plant (52% and 56%, respectively) and grain yield (56%), when compared with non-inoculated control plants. However, seed coating with P. libanensis + R. irregularis single-isolate (coatPR) did not influence cowpea grain yield. Grain lipid content was significantly higher (25%) in coatPMR plants in comparison with control. Higher soil organic matter and lower pH were observed in the coatPMR treatment. CONCLUSIONS: Our findings indicate that cowpea field productivity can be improved by seed coating with PGPR and multiple AM fungal isolates under low-input agricultural systems. © 2019 Society of Chemical Industry.


Assuntos
Produção Agrícola/métodos , Glomeromycota/fisiologia , Pseudomonas/fisiologia , Sementes/microbiologia , Vigna/crescimento & desenvolvimento , Micorrizas/fisiologia , Sementes/crescimento & desenvolvimento , Solo/química , Vigna/microbiologia
2.
J Sci Food Agric ; 100(4): 1577-1587, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31769028

RESUMO

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.


Assuntos
Inoculantes Agrícolas/fisiologia , Antioxidantes/metabolismo , Glomeromycota/fisiologia , Alface/microbiologia , Alface/fisiologia , Micorrizas/fisiologia , Catalase/genética , Catalase/metabolismo , Alface/genética , Alface/crescimento & desenvolvimento , Estresse Oxidativo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tolerância ao Sal , Cloreto de Sódio/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo
3.
J Sci Food Agric ; 100(4): 1816-1821, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31825527

RESUMO

BACKGROUND: Low-cost organic fertilizers, such as coconut powder and vermicompost, and arbuscular mycorrhizal fungi (AMF) may benefit the Passiflora edulis f. flavicarpa plant. However, it has not been established whether the joint application of these inputs may increase the production of vitexin and other molecules associated with the phytotherapeutic properties of this plant. Here, we tested the hypothesis that the application of AMF and organic fertilizers maximizes the production of bioactive compounds in leaves of P. edulis. RESULTS: The inoculation of Acaulospora longula into P. edulis grown in fertilization-free soil promoted an increase of 86% in the concentration of leaf vitexin, 10.29% in the concentration of total phenols, and 13.78% in the concentration of total tannins in relation to the AMF-free control, rendering soil fertilization superfluous. CONCLUSION: The application of A. longula increases the production of foliar biomolecules, such as vitexin, in yellow passion fruit plants. Thus, the addition of coconut powder and vermicompost to the substrate composition is not necessary, leading to the commercialized production of phytomass in the herbal medicines industry. © 2019 Society of Chemical Industry.


Assuntos
Apigenina/metabolismo , Glomeromycota/fisiologia , Micorrizas/fisiologia , Passiflora/microbiologia , Folhas de Planta/química , Apigenina/análise , Fertilizantes/análise , Passiflora/química , Passiflora/crescimento & desenvolvimento , Passiflora/metabolismo , Fenóis/análise , Fenóis/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Taninos/análise , Taninos/metabolismo
4.
Plant Biol (Stuttg) ; 22(1): 62-69, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31464065

RESUMO

Arbuscular mycorrhizal fungi (AMF) is an effective way to remove heavy metals' inhibition on plants, however, few relevant research attempts have been made to determine the contribution of AMF to the physiological and biochemical changes related to the enhanced copper tolerance of Phragmites australis under metal-stressed conditions. In this study, the effects of AMF inoculation on P. australis under different concentrations of copper stress were investigated according to the changes in the parameters related to growth and development, and photosynthetic charateristics. Then, differentially expressed proteins (DEPs) were evaluated by the Isobaric Tag for Relative and Absolute Quantification (iTRAQ) system, which could accurately quantify the DEPs by measuring peak intensities of reporter ions in tandem mass spectrometry (MS/MS) spectra. It was found that AMF inoculation may relieve the photosynthesis inhibition caused by copper stress on P. australis and thus promote growth. Proteomic analysis results showed that under copper stress, the inoculation of R. irregularis resulted in a total of 459 differently-expressed proteins (200 up-regulated and 259 down-regulated) in root buds. In addition, the photosynthetic changes caused by AMF inoculation mainly involve the up-regulated expression of transmembrane protein-pigment complexes CP43 (photosystem II) and FNR (ferredoxin-NADP+ oxidoreductase related to photosynthetic electron transport). These results indicate that AMF could effectively improve the growth and physiological activity of P. australis under copper stress, and thus provides a new direction and instructive evidence for determining the mechanisms by which AMF inoculation enhances the copper tolerance of plants.


Assuntos
Cobre , Micorrizas , Fotossíntese , Poaceae , Estresse Fisiológico , Cobre/toxicidade , Micorrizas/fisiologia , Fotossíntese/fisiologia , Poaceae/efeitos dos fármacos , Poaceae/microbiologia , Proteômica , Espectrometria de Massas em Tandem
5.
Insect Sci ; 27(1): 99-112, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30039604

RESUMO

This study sheds light on a poorly understood area in insect-plant-microbe interactions, focusing on aphid probing and feeding behavior on plants with varying levels of arbuscular mycorrhizal (AM) fungus root colonization. It investigates a commonly occurring interaction of three species: pea aphid Acyrthosiphon pisum, barrel medic Medicago truncatula, and the AM fungus Rhizophagus irregularis, examining whether aphid-feeding behavior changes when insects feed on plants at different levels of AM fungus colonization (42% and 84% root length colonized). Aphid probing and feeding behavior was monitored throughout 8 h of recording using the electrical penetration graph (EPG) technique, also, foliar nutrient content and plant growth were measured. Summarizing, aphids took longer to reach their 1st sustained phloem ingestion on the 84% AM plants than on the 42% AM plants or on controls. Less aphids showed phloem ingestion on the 84% AM plants relative to the 42% AM plants. Shoots of the 84% AM plants had higher percent carbon (43.7%) relative to controls (40.5%), and the 84% AM plants had reduced percent nitrogen (5.3%) relative to the 42% AM plants (6%). In conclusion, EPG and foliar nutrient data support the hypothesis that modifications in plant anatomy (e.g., thicker leaves), and poor food quality (reduced nitrogen) in the 84% AM plants contribute to reduced aphid success in locating phloem and ultimately to differences in phloem sap ingestion. This work suggests that M. truncatula plants benefit from AM symbiosis not only because of increased nutrient uptake but also because of reduced susceptibility to aphids.


Assuntos
Afídeos/fisiologia , Herbivoria , Medicago truncatula/microbiologia , Medicago truncatula/fisiologia , Micorrizas/fisiologia , Animais , Antibiose , Comportamento Alimentar , Nutrientes/análise , Folhas de Planta/fisiologia
6.
Plant Physiol Biochem ; 144: 157-165, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31568958

RESUMO

Ectomycorrhizas have been reported to increase plant tolerance to drought. However, the mechanisms involved are not yet fully understood. Membranes are the first targets of degradation during drought, and growing evidences support a role for membrane lipids in plant tolerance and adaptation to drought. We have previously shown that improved tolerance of ectomycorrhizal oak plants to drought could be related to leaf membrane lipid metabolism, namely through an increased ability to sustain fatty acid content and composition, indicative of a higher membrane stability under stress. Here, we analysed in deeper detail the modulation of leaf lipid metabolism in oak plants mycorrhized with Pisolithus tinctorius and subjected to drought stress. Results show that mycorrhizal plants show patterns associated with water deficit tolerance, like a higher content of chloroplast lipids, whose levels are maintained upon drought stress. Likewise, mycorrhizal plants show increased levels of unsaturated fatty acids in the chloroplast phosphatidylglycerol lipid fraction. As a common response to drought, the digalactosyldiacyloglycerol/monogalactosyldiacyloglycerol ratio increased in the non-mycorrhizal plants, but not in the mycorrhizal plants, associated to smaller alterations in the expression of galactolipid metabolism genes, indicative of a higher drought tolerance. Under drought, inoculated plants showed increased expression of genes involved in neutral lipids biosynthesis, which could be related to an increased ability to tolerate drought stress. Overall, results from this study provide evidences of the involvement of lipid metabolism in the response of ectomycorrhizal plants to water deficit and point to an increased ability to maintain a stable chloroplast membrane functional integrity under stress.


Assuntos
Cloroplastos/fisiologia , Secas , Micorrizas/fisiologia , Quercus/fisiologia , Cloroplastos/metabolismo , Quercus/metabolismo , Simbiose/fisiologia
7.
J Basic Microbiol ; 59(12): 1229-1237, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31642093

RESUMO

Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria inhabit the plant rhizosphere. Both functional groups can influence plant community structures, and interactions between them can vary from being synergistic to antagonistic. HCN-producing Pseudomonas protegens CHA0 is a plant growth-promoting rhizobacterium. P. protegens CHA0 has been shown to weakly attach to AMF hyphae. Here, we analyze the effect of P. protegens CHA0 on the viability of intraradical AMF hyphae. Using pot experiments, we have grown mycorrhizal and nonmycorrhizal Sorghum vulgare var. M35 with P. protegens CHA0 or HCN- mutant P. protegens CHA77, which did not produce HCN. Mycorrhizal and nonmycorrhizal Sorghum grown without CHA0 or CHA77 served as the control. While metabolically active AMF was not detected in mycorrhizal plants grown with HCN+ CHA0, the percentage of root colonization of metabolically active AMF in plants grown with HCN- CHA77 was lower than in the control. Root phosphorus was highest in mycorrhizal plants grown with HCN+ CHA0, but root Fe was higher in plants grown with the bacterial strains. Our results indicate that HCN-producing P. protegens can affect the viability of intraradical AMF.


Assuntos
Glomeromycota/fisiologia , Cianeto de Hidrogênio/metabolismo , Interações Microbianas , Micorrizas/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Pseudomonas/metabolismo , Sorghum/microbiologia , Biomassa , Nutrientes/metabolismo , Reguladores de Crescimento de Planta/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas/genética , Rizosfera , Microbiologia do Solo , Sorghum/metabolismo
8.
Ecotoxicol Environ Saf ; 186: 109783, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31629192

RESUMO

Chemical fungicides are effective tools in controlling plant pathogens; however, these chemicals can, on the other hand, distress the ecosystem. Accordingly, the current research investigates the potentiality of substituting traditional chemical fungicides by inducing plant resistance against infection with soil-born pathogens i.e. Sclerotium rolfsii in the presence of mycorrhizae (AMF) as plant inoculants and one of the following amendments: humic acid, sulphex (a mixture of canola oil and diluted sulphuric acid) and paclobutrazol (ABZ). To attain the abovementioned objective, a field (mildly infected with S. rolfsii) was cultivated with Helianthus tuberosus (a perennial plant belongs to the Asteraceae family) for two successive seasons (2014 and 2015) and the above-mentioned treatments were tested for their feasibilities in controlling S. rolfsii infection against the chemical fungicide "Vitavax-200" either solely or in combinations in a complete randomized block design. Inoculating plants with AMF or amending soils with either humic acid, Sulphex or ABZ solely increased significantly the activities of plant defense enzymes by approximately 1.5-2.1 folds higher than the control treatment. These treatments also improved NPK availability in soil and; hence, increased their contents within plant tubers. Consequently, these treatments decreased the disease incidence and severity caused by S. rolfsii while improved shoot biomass and tuber yield. In spite of that, these results stood below the prospective of the fungicide treatment. The integrated treatments i.e. "humic acid + AMF", "Sulphex + AMF" and "ABZ + AMF" caused further significant improvements in both NPK availabilities in soil and plant areal bio-masses. This probably induced further plant resistance against the investigated soil-borne pathogen while recorded insignificant variations in disease incidence and severity when compared with the fungicide treatment. Moreover, the integrated treatments increased the tuber yields beyond those attained for the fungicide treatment. Accordingly, such integrated strategies can completely substitute the chemical fungicides; thus, minimize their negative impacts on the ecosystem.


Assuntos
Basidiomycota/fisiologia , Resistência à Doença/fisiologia , Recuperação e Remediação Ambiental/métodos , Helianthus/microbiologia , Micorrizas/fisiologia , Microbiologia do Solo , Biomassa , Fungicidas Industriais/análise , Helianthus/metabolismo , Helianthus/fisiologia , Nutrientes/análise , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Distribuição Aleatória , Solo/química
9.
J Plant Res ; 132(6): 777-788, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31617040

RESUMO

In general, Glomeromycotina was thought to be the earliest fungi forming mycorrhiza-like structure (MLS) in land plant evolution. In contrast, because the earliest divergent lineage of extant land plants, i.e. Haplomitriopsida liverworts, associates only with Mucoromycotina mycobionts, recent studies suggested that those fungi are novel candidates for the earliest mycobionts. Therefore, Mucoromycotina-Haplomitriopsida association currently attracts attention as an ancient mycorrhiza-like association. However, mycobionts were identified in only 7 of 16 Haplomitriopsida species and the mycobionts diversity of this lineage is largely unclarified. To clarify the taxonomic composition of mycobionts in Haplomitriopsida, we observed MLSs in the rhizome of Haplomitrium mnioides (Haplomitriopsida), the Asian representative Haplomitriopsida species, and conducted molecular identification of mycobionts. It was recorded for the first time that Glomeromycotina and Mucoromycotina co-occur in Haplomitriopsida as mycobionts. Significantly, the arbuscule-like branching (ALB) of Glomeromycotina was newly described. As the Mucoromycotina fungi forming MLSs in H. mnioides, Endogonaceae and Densosporaceae were detected, in which size differences of hyphal swelling (HS) were found between the fungal families. This study provides a novel evidence in the MLS of Haplomitriopsida, i.e. the existence of Glomeromycotina association as well as the dominant Mucoromycotina association. In addition, since hyphal characteristics of the HS-type MLS were quite similar to those of fine endophytes (FE) of Endogonales in other bryophytes and vascular plants previously described, this MLS is suggested to be included in FE. These results suggest that Glomeromycotina and Mucoromycotina were acquired concurrently as the mycobionts by the earliest land plants evolved into arbuscular mycorrhizae and FE. Therefore, dual association of Haplomitriopsida, with Endogonales and Glomeromycotina will provide us novel insight on how the earliest land plants adapted to terrestrial habitats with fungi.


Assuntos
Endófitos/fisiologia , Fungos/fisiologia , Hepatófitas/fisiologia , Micorrizas/fisiologia , Simbiose , Glomeromycota/fisiologia , Hepatófitas/microbiologia
10.
Plant Physiol Biochem ; 144: 292-299, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31600710

RESUMO

Arbuscular mycorrhizas absorb water from soil to host plants, while the relationship between mycorrhizas and aquaporins (AQPs, membrane water channel proteins, which function in water transport) in mycorrhizal plants is unclear. In this study, Funneliformis mosseae-colonized trifoliate orange (Poncirus trifoliata) seedlings were grown in pots fitted with 37-µm nylon meshes at the bottom of each pot to allow mycorrhizal hyphae absorb water from an outer beaker. The expression of seven plasma membrane intrinsic proteins (PIPs) genes, six tonoplast intrinsic proteins (TIPs) genes, and four nodulin-26 like intrinsic proteins (NIPs) genes were analyzed in roots of both well-watered (WW) and drought stressed (DS) plants. The six-week DS plants dramatically increased hyphal water absorption rate by 1.4 times, as compared with WW plants. Mycorrhizal plants exhibited greater plant growth performance, leaf water status (water potential and relative water content), and gas exchange under both WW and DS conditions. Mycorrhizal inoculation induced diverse expression patterns in these AQPs under WW: up-regulation of PtNIP1;1, PtPIP2;1, and PtPIP2;5, down-regulation of PtNIP1;2, PtNIP6;1, PtPIP1;2, PtPIP1;5, PtPIP2;8, PtTIP1;1, PtTIP1;2, PtTIP1;3, and PtTIP5;1, and no changes in other AQPs. However, the expression of PtPIPs and PtNIPs was down-regulated by mycorrhizal inoculation under DS, and PtTIPs was not induced by mycorrhizal colonization under DS. The expression pattern of AQPs in response to mycorrhizas under DS is a way of mycorrhizal plants to minimize water loss.


Assuntos
Secas , Micorrizas/fisiologia , Poncirus/metabolismo , Poncirus/microbiologia , Microbiologia do Solo , Simbiose
11.
J Basic Microbiol ; 59(12): 1217-1228, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31613012

RESUMO

Arbuscular mycorrhizal fungi (AMF), particularly the Glomerales group, play a paramount role in plant nutrient uptake, and abiotic and biotic stress management in rice, but recent evidence revealed that elevated CO2 concentration considerably reduces the Glomerales group in soil. In view of this, the present study was initiated to understand the interaction effect of native Glomerales species application in rice plants (cv. Naveen) under elevated CO2 concentrations (400 ± 10, 550 ± 20, and 700 ± 20 ppm) in open-top chambers. Three different modes of application of the AMF inoculum were evaluated, of which, combined application of AMF at the seedling production and transplanting stages showed increased AMF colonization, which significantly improved grain yield by 25.08% and also increased uptake of phosphorus by 18.2% and nitrogen by 49.5%, as observed at 700-ppm CO2 concentration. Organic acids secretion in rice root increased in AMF-inoculated plants exposed to 700-ppm CO2 concentration. To understand the overall effect of CO2 elevation on AMF interaction with the rice plant, principal component and partial least square regression analysis were performed, which found both positive and negative responses under elevated CO2 concentration.


Assuntos
Dióxido de Carbono/farmacologia , Glomeromycota/efeitos dos fármacos , Glomeromycota/fisiologia , Micorrizas/efeitos dos fármacos , Micorrizas/fisiologia , Oryza/microbiologia , Simbiose/efeitos dos fármacos , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Glomeromycota/crescimento & desenvolvimento , Micorrizas/crescimento & desenvolvimento , Nitrogênio/análise , Nitrogênio/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Fósforo/análise , Fósforo/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Solo/química , Esporos Fúngicos/fisiologia
12.
Ecotoxicol Environ Saf ; 186: 109744, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31627093

RESUMO

Biological strategy of utilization of plants-microbe's interactions to remediate cadmium (Cd) contaminated soils is effective and practical. However, limited evidence at transcriptome level is available about how microbes work with host plants to alleviate Cd stress. In the present study, comparative transcriptomic analysis was performed between maize seedlings inoculated with arbuscular mycorrhizal (AM) fungi and non-AM fungi inoculation under distinct concentrations of CdCl2 (0, 25, and 50 mg per kg soil). Significantly higher levels of Cd were found in root tissues of maize colonized by AM fungi, whereas, Cd content was reduced as much as 50% in leaf tissues when compared to non-AM seedlings, indicating that symbiosis between AM fungi and maize seedlings can significantly block translocation of Cd from roots to leaf tissues. Moreover, a total of 5827 differentially expressed genes (DEG) were determined and approximately 68.54% DEGs were downregulated when roots were exposed to high Cd stress. In contrast, 67.16% (595) DEGs were significantly up-regulated when seedlings were colonized by AM fungi under 0 mg CdCl2. Based on hierarchical clustering analysis, global expression profiles were split into eight distinct clusters. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that hundreds of genes functioning in plant hormone signal transduction, mitogen-activated protein kinase (MAPK) signaling pathway and glutathione metabolism were enriched. Furthermore, MapMan pathway analysis indicated a more comprehensive overview response, including hormone metabolism, especially in JA, glutathione metabolism, transcription factors and secondary metabolites, to Cd stress in mycorrhizal maize seedlings. These results provide an overview, at the transcriptome level, of how inoculation of maize seedlings by AM fungi could facilitate the relief of Cd stress.


Assuntos
Cádmio/efeitos adversos , Glomeromycota/fisiologia , Micorrizas/fisiologia , Poluentes do Solo/efeitos adversos , Simbiose , Transcriptoma , Zea mays/efeitos dos fármacos , Cádmio/metabolismo , Regulação para Baixo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plântula/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Estresse Fisiológico , Zea mays/genética , Zea mays/metabolismo , Zea mays/microbiologia
13.
Mycorrhiza ; 29(5): 475-487, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31506745

RESUMO

Arbuscular mycorrhizal fungi (AMF) play a central role in rhizosphere functioning as they interact with both plants and soil microbial communities. The conditions in which AMF modify plant physiology and microbial communities in the rhizosphere are still poorly understood. In the present study, four different plant species, (clover, alfalfa, ryegrass, tall fescue) were cultivated in either sterilized (γ ray) or non-sterilized soil and either inoculated with a commercial AMF (Glomus LPA Val 1.) or not. After 20 weeks of cultivation, the mycorrhizal rate and shoot and root biomasses were measured. The abundance and composition of bacteria, archaea, and fungi were analyzed, respectively, by quantitative PCR (qPCR) and fingerprinting techniques. Whilst sterilization did not change the AMF capacity to modify plant biomass, significant changes in microbial communities were observed, depending on the taxon and the associated plant. AMF inoculation decreases both bacterial and archaeal abundance and diversity, with a greatest extent in sterilized samples. These results also show that AMF exert different selections on soil microbial communities according to the plant species they are associated with. This study suggests that the initial abundance and diversity of rhizosphere microbial communities should be considered when introducing AMF to cultures.


Assuntos
Fabaceae/microbiologia , Microbiota/fisiologia , Micorrizas/fisiologia , Poaceae/microbiologia , Rizosfera , Glomeromycota/fisiologia , Microbiologia do Solo
14.
ScientificWorldJournal ; 2019: 2758501, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31391794

RESUMO

Coastal sand dunes are hips and strips formed by sand particles which are eroded and ground rock, derived from terrestrial and oceanic sources. This is considered as a specialized ecosystem characterized by conditions which are hostile for life forms like high salt, low moisture, and low organic matter content. However, dunes are also inhabited by diverse groups of flora, fauna, and microorganisms specifically adapted to these situations. Microbial groups like fungi, bacteria, and actinobacteria are quite abundant in the rhizosphere, phyllosphere, and inside plants which are very much essential for the integration of dunes. Microorganisms in this ecosystem have been found to produce a number of bioactive metabolites which are of great importance to agriculture and industries. Many species of arbuscular mycorrhizal fungi and Rhizobia associated with the roots of dune flora are prolific producers of plant growth promoting biochemicals like indole acetic acid. In addition to that bacteria belonging to Pseudomonas sp., Gammaproteobacteria have been found to have antagonistic activity towards plant pathogens like Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Botrytis cinerea. Many neutrophilic and alkaliphilic eubacterial species, endophytic fungi from dunes have proved their ability for the production of extracellular enzymes like cellulase, pectinase, amylase, protease, tannase, chitinase, etc., which are of great importance to various industries. In this context, it is relevant to observe that the state of Odisha in India has a 480km long coast having numerous sand dunes. These dunes are rich in floral and faunal diversity. However, a comprehensive study is yet to be taken up to explore the microbial diversity and their bioactive potential in this region. The current review sheds light on the enormous potential of sand dune microorganisms in the coast and surfaced the idea and need for such exploration in the state of Odisha, India.


Assuntos
Biodiversidade , Areia , Microbiologia do Solo , Endófitos/fisiologia , Índia , Micorrizas/fisiologia , Rizosfera
15.
Sci Total Environ ; 686: 1129-1139, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412509

RESUMO

Global change apart from ecosystem processes also influences the community structure of key organisms, such as arbuscular mycorrhizal fungi (AMF). We conducted a 3-year experiment where we suppressed with benomyl mycorrhiza to understand how AMF alter the plant community structure under warming and nitrogen (N) addition. The elemental content and foliar tissue stoichiometry of the dominant species Leymus chinensis and the subordinate species Puccinellia tenuiflora were studied along with soil nutrient stoichiometries. Overall, N addition enhanced plant N: phosphorus (P) ratios at a greater level than experimental warming did. Under global change conditions, AMF symbionts significantly increased soil available P concentrations, promoted plant P absorption and decreased the plant N:P ratios. AMF alleviate P limitation by reducing plant N:P ratios. Our results highlight that the negative influence of global change on plant productivity might cancel each other out through the additive effects of AMF and that global change will increase the dependency of plants on their mycorrhizal symbionts.


Assuntos
Aquecimento Global , Micorrizas/fisiologia , Nitrogênio/fisiologia , Fósforo/fisiologia , Poaceae/microbiologia , China , Fertilizantes/análise , Temperatura Alta , Nitrogênio/administração & dosagem
16.
Microbes Environ ; 34(3): 327-333, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31413228

RESUMO

Arbuscular mycorrhizal (AM) fungi play a significant role in the establishment and resilience of vegetation in harsh environments, such as volcanic slopes, in which soil is frequently disturbed by ash falling and erosion. We characterized AM fungal communities associated with a pioneer grass in a volcanic slope based on the disturbance tolerance of the fungi, addressing the hypothesis that soil disturbance is a major ecological filter for AM fungi in volcanic ecosystems and, thus, fungi that are more tolerant to soil disturbance are selected at higher elevations (i.e. nearer to the crater). Paired soil-core samples were collected from the rhizosphere of Miscanthus sinensis between the vegetation limit and forest limit on a volcanic slope and used in a trap culture with M. sinensis seedlings, in which one of the paired samples was sieved to destroy hyphal networks (disturbance treatment), while the other was not (intact treatment). Seedlings were grown in a greenhouse for two months, and the roots were subjected to molecular analysis of fungal communities. AM fungal diversity decreased with increasing elevations, in which nested structure was observed. Community dissimilarity between the disturbed and intact communities decreased with increasing elevations, suggesting that communities at higher elevations were more robust against soil disturbance. These results suggest that AM fungi that are more tolerant to soil disturbance are more widely distributed across the ecosystem, that is, they are generalists. The wide distribution of disturbance-tolerant fungi may have significant implications for the rapid resilience of vegetation after disturbance in the ecosystem.


Assuntos
Ecossistema , Micobioma , Micorrizas/fisiologia , Seleção Genética , Microbiologia do Solo , Erupções Vulcânicas , Adaptação Fisiológica , Altitude , Biodiversidade , Micorrizas/classificação , Micorrizas/genética , Micorrizas/isolamento & purificação , Poaceae/microbiologia , Rizosfera , Solo/química
17.
Planta ; 250(5): 1773-1779, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31440828

RESUMO

MAIN CONCLUSION: Accumulation of calcium/calmodulin-dependent protein kinase (CCaMK) in root cell nucleus depends on its kinase activity but not on nuclear symbiotic components crucial for nodulation. Plant calcium/calmodulin-dependent protein kinase (CCaMK) is a key regulator of symbioses with rhizobia and arbuscular mycorrhizal fungi as it decodes symbiotic calcium signals induced by microsymbionts. CCaMK is expressed mainly in root cells and localizes to the nucleus, where microsymbiont-triggered calcium oscillations occur. The molecular mechanisms that control CCaMK localization are unknown. Here, we analyzed the expression and subcellular localization of mutated CCaMK in the roots of Lotus japonicus and found a clear relation between CCaMK kinase activity and its stability. Kinase-defective CCaMK variants showed lower protein levels than the variants with kinase activity. The levels of transcripts driven by the CaMV 35S promoter were similar among the variants, indicating that stability of CCaMK is regulated post-translationally. We also demonstrated that CCaMK localized to the root cell nucleus in several symbiotic mutants, including cyclops, an interaction partner and phosphorylation target of CCaMK. Our results suggest that kinase activity of CCaMK is required not only for the activation of downstream symbiotic components but also for its stability in root cells.


Assuntos
Sinalização do Cálcio , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Cálcio/metabolismo , Lotus/enzimologia , Simbiose , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Núcleo Celular/metabolismo , Lotus/genética , Lotus/microbiologia , Lotus/fisiologia , Mutação , Micorrizas/fisiologia , Fosforilação , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Regiões Promotoras Genéticas/genética , Estabilidade Proteica , Rhizobium/fisiologia
18.
Environ Sci Pollut Res Int ; 26(30): 30794-30807, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31444728

RESUMO

Soil pollution with heavy metals is a major problem in industrial areas. Here, we explored whether zeolite addition to soil and indigenous arbuscular mycorrhizal fungi (AMF) can reduce cadmium (Cd) uptake from soil by bread wheat. We conducted a pot experiment, in which the effects of indigenous soil AMF, zeolite addition, and Cd spiking to soil [0, 5, 10, and 15 mg (kg soil)-1] were tested. Zeolite addition to soil spiked with 15 mg Cd kg-1 decreased the Cd uptake to grains from 11.8 to 8.3 mg kg-1 and 8.9 to 3.3 mg kg-1 in the absence and presence of indigenous AMF, respectively. Positive growth, nitrogen (N), and phosphorous (P) uptake responses to mycorrhization in Cd-spiked soils were consistently magnified by zeolite addition. Zeolite addition to soil stimulated AMF root colonization. The abundance of AMF taxa changed in response to zeolite addition to soil and soil Cd spiking as measured by quantitative polymerase chain reaction. With increasing Cd spiking, the abundance of Funneliformis increased. However, when less Cd was spiked to soil and/or when zeolite was added, the abundance of Claroideoglomus and Rhizophagus increased. This study showed that soil-indigenous AMF and addition of zeolite to soil can lower Cd uptake to the grains of bread wheat and thereby reduce Cd contamination of the globally most important staple food.


Assuntos
Cádmio/farmacocinética , Micorrizas/fisiologia , Poluentes do Solo/farmacocinética , Triticum/crescimento & desenvolvimento , Zeolitas , Inoculantes Agrícolas , Cádmio/análise , Glomeromycota , Nitrogênio/farmacocinética , Fósforo/farmacocinética , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Triticum/efeitos dos fármacos , Triticum/metabolismo
19.
Int J Mol Sci ; 20(17)2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31461957

RESUMO

Arbuscular mycorrhizal fungi (AMF) establish symbiotic interaction with 80% of known land plants. It has a pronounced impact on plant growth, water absorption, mineral nutrition, and protection from abiotic stresses. Plants are very dynamic systems having great adaptability under continuously changing drying conditions. In this regard, the function of AMF as a biological tool for improving plant drought stress tolerance and phenotypic plasticity, in terms of establishing mutualistic associations, seems an innovative approach towards sustainable agriculture. However, a better understanding of these complex interconnected signaling pathways and AMF-mediated mechanisms that regulate the drought tolerance in plants will enhance its potential application as an innovative approach in environmentally friendly agriculture. This paper reviews the underlying mechanisms that are confidently linked with plant-AMF interaction in alleviating drought stress, constructing emphasis on phytohormones and signaling molecules and their interaction with biochemical, and physiological processes to maintain the homeostasis of nutrient and water cycling and plant growth performance. Likewise, the paper will analyze how the AMF symbiosis helps the plant to overcome the deleterious effects of stress is also evaluated. Finally, we review how interactions between various signaling mechanisms governed by AMF symbiosis modulate different physiological responses to improve drought tolerance. Understanding the AMF-mediated mechanisms that are important for regulating the establishment of the mycorrhizal association and the plant protective responses towards unfavorable conditions will open new approaches to exploit AMF as a bioprotective tool against drought.


Assuntos
Micorrizas/fisiologia , Estresse Fisiológico , Adaptação Fisiológica , Secas , Micorrizas/metabolismo , Reguladores de Crescimento de Planta/metabolismo
20.
Mycorrhiza ; 29(5): 503-517, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31456074

RESUMO

During ectomycorrhizal symbioses, up to 30% of the carbon produced in leaves may be translocated to the fungal partner. Given that the leaf response to root colonization is largely unknown, we performed a leaf proteome analysis of Populus × canescens inoculated in vitro with two isolates of Paxillus involutus significantly differing in root colonization rates (65 ± 7% vs 14 ± 7%), together with plant growth and leaf biochemistry analyses to determine the response of plant leaves to ectomycorrhizal root colonization. The isolate that more efficiently colonized roots (isolate H) affected 9.1% of the leaf proteome compared with control plants. Simultaneously, ectomycorrhiza in isolate H-inoculated plants led to improved plant growth and an increased abundance of leaf proteins involved in protein turnover, stress response, carbohydrate metabolism, and photosynthesis. The protein increment was also correlated with increases in chlorophyll, foliar carbon, and carbohydrate contents. Although inoculation of P. × canescens roots with the other P. involutus isolate (isolate L, characterized by a low root colonization ratio) affected 6.8% of the leaf proteome compared with control plants, most proteins were downregulated. The proteomic signals of increased carbohydrate biosynthesis were not detected, and carbohydrate, carbon, and leaf pigment levels and plant biomass did not differ from the noninoculated plants. Our results revealed that the upregulation of the photosynthetic protein abundance and levels of leaf carbohydrate are positively related to rates of root colonization. Upregulation of photosynthetic proteins, chlorophyll, and leaf carbohydrate levels in ectomycorrhizal plants was positively related to root colonization rates and resulted in increased carbon translocation and sequestration underground.


Assuntos
Basidiomycota/fisiologia , Micorrizas/fisiologia , Populus/microbiologia , Proteoma , Fotossíntese/genética , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/microbiologia
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