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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.
Carbohydr Polym ; 229: 115505, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826410

RESUMO

During the establishment of arbuscular mycorrhizal (AM) symbiosis, the fungus and the host plant exchange chemical signals that are crucial to reciprocal recognition. Short-chain chitin oligomers (CO) released by AM fungi are known to trigger symbiotic signaling in all host plant species tested. Here we applied exogenous CO, derived from crustacean exoskeleton, to pot-grown Medicago truncatula inoculated with the AM fungus Funneliformis mosseae and investigated root colonization, plant gene regulation and biomass production. CO treatment strongly promoted AM colonization with significant increases in arbuscule development, biomass production and photosynthetic surface compared to untreated mycorrhizal plants. Gene expression analyses indicated that CO treatment anticipated the expression of MtBCP and MtPT4 plant symbiotic markers, during the first two weeks post inoculation. Altogether, our results provide evidence that plant treatment with symbiotic fungal elicitors, anticipated and enhanced AM development, encouraging the use of CO to promote AM establishment in sustainable agricultural practices.


Assuntos
Quitina/química , Glomeromycota/fisiologia , Medicago truncatula/metabolismo , Medicago truncatula/microbiologia , Micorrizas/fisiologia , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Biomassa , Monóxido de Carbono/farmacologia , Medicago truncatula/efeitos dos fármacos , Medicago truncatula/crescimento & desenvolvimento , Nitrogênio/metabolismo , Simbiose/efeitos dos fármacos
5.
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
6.
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
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: 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
9.
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
10.
Mycorrhiza ; 29(4): 325-339, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31203456

RESUMO

Inoculation of arbuscular mycorrhizal fungi (AMF) as plant growth promoters has mostly been conducted using single-species inoculum. In this study, we investigated whether co-inoculation of different native AMF species induced an improvement of plant growth in an ultramafic soil. We analyzed the effects of six species of AMF from a New Caledonian ultramafic soil on plant growth and nutrition, using mono-inoculations and mixtures comprising different numbers of AMF species, in a greenhouse experiment. The endemic Metrosideros laurifolia was used as a host plant. Our results suggest that, when the plant faced multiple abiotic stress factors (nutrient deficiencies and high concentrations of different heavy metals), co-inoculation of AMF belonging to different families was more efficient than mono-inoculation in improving biomass, mineral nutrition, Ca/Mg ratio, and tolerance to heavy metals of plants in ultramafic soil. This performance suggested functional complementarity between distantly related AMF. Our findings will have important implications for restoration ecology and mycorrhizal biotechnology applied to ultramafic soils.


Assuntos
Inoculantes Agrícolas/fisiologia , Produção Agrícola/métodos , Glomeromycota/fisiologia , Micorrizas/fisiologia , Myrtaceae/crescimento & desenvolvimento , Glomeromycota/classificação , Micorrizas/classificação , Myrtaceae/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia
11.
Mycorrhiza ; 29(4): 389-395, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218402

RESUMO

Arbuscular mycorrhizal fungi (AMF) are considered a potential biotechnological tool for mitigating heavy metal (HM) toxicity. A greenhouse experiment was conducted to evaluate the impacts of the AM fungus Rhizophagus irregularis on cadmium (Cd) uptake, mycorrhizal colonization, and some plant growth parameters of Medicago sativa (alfalfa) in Cd-polluted soils. In addition, expression of two metal chelators (MsPCS1 (phytochelatin synthase) and MsMT2 (metallothionein)) and two metal transporter genes (MsIRT1 and MsNramp1) was analyzed using quantitative real-time PCR (qRT-PCR). Cd addition had a significant negative effect on mycorrhizal colonization. However, AMF symbiosis promoted the accumulation of biomass under both stressed and unstressed conditions compared with non-mycorrhizal (NM) plants. Results also showed that inoculation with R. irregularis significantly reduced shoot Cd concentration in polluted soils. Transcripts abundance of MsPCS1, MsMT2, MsIRT1, and MsNRAMP1 genes were downregulated compared with NM plants indicating that metal sequestration within hyphal fungi probably made Cd concentration insufficient in root cells for induction of these genes. These results suggest that reduction of shoot Cd concentration in M. sativa colonized by R. irregularis could be a promising strategy for safe production of this plant in Cd-polluted soils.


Assuntos
Aminoaciltransferases/genética , Cádmio/metabolismo , Glomeromycota/fisiologia , Medicago sativa/metabolismo , Metalotioneína/genética , Micorrizas/fisiologia , Proteínas de Plantas/genética , Poluentes do Solo/metabolismo , Aminoaciltransferases/metabolismo , Transporte Biológico , Medicago sativa/genética , Medicago sativa/microbiologia , Metalotioneína/metabolismo , Proteínas de Plantas/metabolismo , Simbiose
12.
Mycorrhiza ; 29(4): 375-387, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31227910

RESUMO

In this study, the effect of a mycorrhizal symbiosis on the translocation of Cd from Cd-polluted soil to sorghum roots was investigated using rhizoboxes. A factorial experiment (two factors including fungus inoculation and Cd contamination) in a completely randomized design with three replicates was performed. In the rhizobox rhizosphere compartment, plants were cultivated in uncontaminated soil and mycorrhizal inoculation (inoculated with Claroideoglomus etunicatum or non-inoculated) was performed, and in the other compartment, the soil was contaminated with Cadmium (Cd) at one of three levels (0, 100 mg kg-1 using a non-toxic organic polymer (poly (N-vinyl succinate))-Cd, or 100 mg kg-1 using Cd-nitrate). Cd pollution resulted in a significant decrease in shoot dry weight (from 7.52 to 6.18 and 6.68 g pot-1, from control to polymer-Cd and nitrate-Cd respectively), root mycorrhizal colonization (from 32.33% to 8.16% and 8.33%), shoot phosphorus concentration (from 3.14 to 2.80 and 2.76 g kg-1), and soil carbohydrate (from 12.05 to 10.74 and 10.24 mg g-1), and also resulted in significant increases in soil glomalin (from 595.55 to 660.52 and 690.39 µg g-1). The use of mycorrhizal fungi increased the glomalin content of the soil and improved the studied parameters. The results revealed the key role of Claroideoglomus etunicatum in translocation of Cd in the rhizobox and also in precise control of Cd concentration of plant tissues (increase or decrease of them depending on Cd composition and Cd availability). Poly(N-vinyl succinate) increased Cd availability and Cd concentration of shoot tissue (5.19 mg kg-1) compared to nitrate-Cd (3.68 mg kg-1) and could be recommended for improving phytoremediation.


Assuntos
Cádmio/metabolismo , Glomeromycota/fisiologia , Micorrizas/fisiologia , Poluentes do Solo/metabolismo , Sorghum/metabolismo , Sorghum/microbiologia , Simbiose , Biodegradação Ambiental , Transporte Biológico , Cádmio/análise , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Microbiologia do Solo , Poluentes do Solo/análise , Sorghum/química
13.
Plant Cell Physiol ; 60(10): 2272-2281, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31241164

RESUMO

Arbuscular mycorrhizal fungi (AMF) establish symbiotic relationships with most land plants, mainly for the purpose of nutrient exchange. Many studies have revealed the regulation of processes in AMF, such as nutrient absorption from soil, metabolism and exchange with host plants, and the genes involved. However, the spatial regulation of the genes within the structures comprising each developmental stage is not well understood. Here, we demonstrate the structure-specific transcriptome of the model AMF species, Rhizophagus irregularis. We performed an ultra-low input RNA-seq analysis, SMART-seq2, comparing five extraradical structures, germ tubes, runner hyphae, branched absorbing structures (BAS), immature spores and mature spores. In addition, we reanalyzed the recently reported RNA-seq data comparing intraradical mycelium and arbuscule. Our analyses captured the distinct features of each structure and revealed the structure-specific expression patterns of genes related to nutrient transport and metabolism. Of note, the transcriptional profiles suggest distinct functions of BAS in nutrient absorption. These findings provide a comprehensive dataset to advance our understanding of the transcriptional dynamics of fungal nutrition in this symbiotic system.


Assuntos
Daucus carota/microbiologia , Regulação Fúngica da Expressão Gênica , Glomeromycota/genética , Micorrizas/genética , Nutrientes/metabolismo , Transcriptoma , Transporte Biológico , Perfilação da Expressão Gênica , Biblioteca Gênica , Glomeromycota/fisiologia , Hifas , Micélio , Micorrizas/fisiologia , Raízes de Plantas/microbiologia , Análise de Sequência de RNA , Solo/química , Esporos Fúngicos , Simbiose
14.
Braz J Microbiol ; 50(3): 593-601, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31250404

RESUMO

Arbuscular mycorrhizal (AM) fungi show high promiscuity in terms of host. Effector proteins expressed by AM fungi are found important in establishing interaction with host. However, the mechanistic underlying host-specific interactions of the fungi remain unknown. The present study aimed (i) to identify effectors encoded by Rhizophagus proliferus and (ii) to understand molecular specificity encoded in effectors for interaction with specific plant species. The effectors predicted from the whole genome sequence were annotated by homology search in NCBI non-redundant protein, Interproscan, and pathogen-host interaction (PHI) databases. In total, 416 small secreted peptides (SSPs) were predicted, which were effector peptides with presence of nuclear localization signal, small cysteine-rich, and repeat-containing proteins domains. Similar to the functionally validated SP7 effectors in Rhizophagus irregularis, two proteins (RP8598 and RP23081) were identified in R. proliferus. To understand whether interaction between SP7 and the plant target protein, ERF19, is specific in nature, we examined protein-peptide interaction using in silico molecular docking. Pairwise interaction of RP8598 and RP23081 with the ethylene-responsive factors (ERF19) coded by five different plant species (Lotus japonicus, Solanum lycopersicum, Ocimum tenuiflorum, Medicago truncatula, Diospyros kaki) was investigated. Prediction of high-quality interaction of SP7 effector with ERF19 protein expressed only by specific plant species was observed in in silico molecular docking, which may reiterate the role of effectors in host specificity. The outcomes from our study indicated that sequence precision encoded in the effector peptides of AM fungi and immunomodulatory proteins of host may regulate host specificity in these fungi.


Assuntos
Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Glomeromycota/fisiologia , Plantas/microbiologia , Proteínas Fúngicas/genética , Glomeromycota/química , Glomeromycota/genética , Especificidade de Hospedeiro , Interações Hospedeiro-Patógeno , Simulação de Acoplamento Molecular , Micorrizas/química , Micorrizas/genética , Micorrizas/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas/química , Plantas/genética , Plantas/metabolismo , Domínios Proteicos
15.
Nat Microbiol ; 4(10): 1654-1660, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31235957

RESUMO

Arbuscular mycorrhizal (AM) fungi are obligate symbionts that depend on living host plants to complete their life cycle1,2. This feature, which leads to their unculturability in the absence of plants, strongly hinders basic research and agricultural application of AM fungi. However, at least one AM fungus can grow and develop fertile spores independently of a host plant in co-culture with the bacterium Paenibacillus validus3. The bacteria-derived substances are thought to act as stimulants or nutrients for fungal sporulation, but these molecules have not been identified. Here, we show that (S)-12-methyltetradecanoic acid4,5, a methyl branched-chain fatty acid isolated from bacterial cultures, stimulates the branching of hyphae germinated from mother spores and the formation of secondary spores in axenic culture of the AM fungus Rhizophagus irregularis. Extensive testing of fatty acids revealed that palmitoleic acid induces more secondary spores than the bacterial fatty acid in R. irregularis. These induced spores have the ability to infect host plant roots and to generate daughter spores. Our work shows that, in addition to a major source of organic carbon6-9, fatty acids act as stimulants to induce infection-competent secondary spores in the asymbiotic stage and could provide the key to developing the axenic production of AM inoculum.


Assuntos
Ácidos Graxos/farmacologia , Glomeromycota/efeitos dos fármacos , Micorrizas/efeitos dos fármacos , Meios de Cultivo Condicionados , Ácidos Graxos/metabolismo , Ácidos Graxos Monoinsaturados/farmacologia , Regulação Fúngica da Expressão Gênica , Glomeromycota/genética , Glomeromycota/crescimento & desenvolvimento , Glomeromycota/fisiologia , Hifas/efeitos dos fármacos , Hifas/genética , Hifas/crescimento & desenvolvimento , Hifas/fisiologia , Micorrizas/genética , Micorrizas/crescimento & desenvolvimento , Micorrizas/fisiologia , Paenibacillus/metabolismo , Raízes de Plantas/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/fisiologia
16.
Environ Sci Pollut Res Int ; 26(20): 20689-20700, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31104234

RESUMO

Cadmium (Cd) toxicity in agricultural crops is a widespread problem. Little is known about biochar and arbuscular mycorrhizal fungi (AMF) effect on Cd concentration in maize plant either applied separately or in combination. Current study was performed to demonstrate effects of biochar and Rhizophagus clarus on plant growth, photosynthesis activity, nutrients (P, Ca, Mg, Fe, Cu, and Mn), and Cd concentration in maize grown in Cd-spiked soil. The alkaline soil was spiked by Cd factor at three levels: 0 (Cd 0), 5 (Cd 5), and 10 (Cd 10) mg/kg; biochar factor at two levels: 0 and 1%; and mycorrhizal inoculum factor at two levels: MF0 and MF1 (R. clraus). Plants were harvested after 70 days of seed germination, and various morphological and physiological parameters, as well as elemental concentration and root colonization, were recorded. Addition of biochar increased plant biomass by 21% (Cd 5) and 93% (Cd 10), MF1 enhanced by 53% (Cd 0) and 69% (Cd 10), while biochar + MF1 enhanced dry plant biomass by 70% (Cd 0) and 94% (Cd 10). Results showed maximum increase of 94% (Cd 10) in plant biomass was observed in Cd-spiked soil. Root colonization decreased proportionally by increasing Cd concentration and at Cd 10, colonization was 36.7% and 31.7% for MF1 and biochar + MF1 treatments, respectively. Besides that, addition of biochar enhanced root attributes (root length, volume, and surface area) by 34-58% compared to control in Cd 10. The MF1 increased these attributes by 11-78% while biochar + MF1 enhanced by 32-61% in Cd-spiked soil. However, biochar + MF1 neutralized Cd stress in maize plant for gaseous attributes (assimilation rate, transpiration rate, intercellular CO2, and stomatal conductance). The MF1 enhanced Cd concentration in plant as it was 3.32 mg/kg in Cd 5 and 6.73 mg/kg in Cd 10 treatments while addition of biochar phytostabilized Cd and reduced its concentration in plants by 2.0 mg/kg in Cd 5 and 4.27 mg/kg in Cd 10. The biochar + MF1 had 2.9 mg/kg and 4.8 mg/kg Cd concentration in Cd 5 and Cd 10 plants, respectively. Phosphorus concentration was augmented in shoots (up to 26%) and roots (up to 20%) of maize plant in biochar-amended soil than control plants. In biochar + MF1, concentration of P was 1.01% and 0.73% in Cd 5 and Cd 10, respectively. It is concluded that biochar + MF1 treatment enhances plant biomass while addition of sole biochar reduced Cd uptake, slightly indifferent to earlier treatment.


Assuntos
Cádmio/metabolismo , Carvão Vegetal/química , Glomeromycota/fisiologia , Micorrizas/fisiologia , Poluentes do Solo/metabolismo , Zea mays/crescimento & desenvolvimento , Biomassa , Cádmio/química , Cádmio/toxicidade , Carvão Vegetal/análise , Nutrientes/metabolismo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Zea mays/metabolismo , Zea mays/microbiologia
17.
World J Microbiol Biotechnol ; 35(6): 81, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31134389

RESUMO

TiO2 nanoparticles (TiO2NPs) is one of the most widely used nanomaterials. Arbuscular mycorrhizal fungi (AMF) are an important and widely distributed group of soil microorganisms, which promote the absorption of nutrients by host plants and increase their tolerance to contaminants. However, the effects and mechanisms of AMF on plant TiO2NPs tolerance in wetland habitats are not clear. In this experiment, under the conditions of three soil moisture contents (drought 50%, normal 70% and flooding 100%) and four TiO2NPs concentrations (0, 100, 200 and 500 mg kg-1), the effects of Funneliformis mosseae on the growth, antioxidant enzyme activities, osmotic substances and the absorption and accumulation of Ti in the Phragmites australis (reed) seedlings were studied. The results showed that the inoculation of F. mosseae under three moisture content conditions significantly increased the plant nutrition and root activities of reeds. Compared with the non-inoculated control, inoculation with F. mosseae increased the activities of antioxidant enzymes, the contents of chlorophyll, proline, soluble protein, and free amino acids, and significantly reduced the contents of malondialdehyde (MDA) and reactive oxygen species (ROS) of leaves. The accumulating ability of inoculated reeds to Ti was significantly higher than that of non-inoculated controls (P < 0.05), and inoculation of F. mosseae changed the distribution of Ti in reeds, increased the accumulation of Ti in roots. It's confirmed that inoculation of F. mosseae under three water conditions could improve the plant growth and nutrition, the activities of antioxidant enzymes, and enhance the reeds tolerance to TiO2NPs in this study.


Assuntos
Glomeromycota/fisiologia , Nanopartículas/toxicidade , Poaceae/efeitos dos fármacos , Poaceae/microbiologia , Plântula/crescimento & desenvolvimento , Estresse Fisiológico , Titânio/toxicidade , Água/metabolismo , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Secas , Tolerância a Medicamentos , Malondialdeído/metabolismo , Osmose , Desenvolvimento Vegetal , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/microbiologia , Microbiologia do Solo , Áreas Alagadas
18.
Int J Mol Sci ; 20(7)2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30934751

RESUMO

Monotonous cucumber double-cropping systems under plastic greenhouse vegetable cultivation (PGVC) previously intensified by long-term anthropogenic activities and manipulative treatments leads to a crop productivity reduction and soil biota disturbances. In this study, the role of the indigenous arbuscular mycorrhizal strain (AM: Glomus versiforme L.) and organic substrate (GS: Garlic stalk) application were assessed for plant microbe interaction and crop productivity feedback in a greenhouse (2016⁻2018) under a cultivated Anthrosol characterized as a replanted degraded soil. We found that repetitively adding AM inocula with organic substrates (GS) improved the cucumber growth and physiology. The useful trait of AM symbiosis with C-amended organic substrates preferentially manifested as increased root colonization, hyphal density proliferation, AM sporulation, root activity, and suppressed Fusarium incidence. The post AM development further prevailed the synergistic interaction, and the co-inoculation effect resulted in an increase in fruit nutrition uptake, seasonal cucumber yield and fruit quality attributes. Illumina MiSeq analysis of the 18S rRNA gene amplicons revealed that the dominant AM genera that are particularly enriched with the Glomus taxon may be important ecological drivers associated with plant productivity and fruit quality characteristics. These results suggest that the AM-organic substrate association might be a pragmatic option for use as an economic and efficient biological resource and as a newly-sustainable plant microbe mediator to enhance the regional ecosystem services and plant productivity of the anthropogenic PGVC of this region.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/microbiologia , Frutas/normas , Glomeromycota/fisiologia , Atividades Humanas , Micorrizas/fisiologia , Compostos Orgânicos/farmacologia , Microbiologia do Solo , Biodiversidade , Frutas/microbiologia , Humanos , Fotossíntese/efeitos dos fármacos , Desenvolvimento Vegetal/efeitos dos fármacos , Análise de Componente Principal , Estações do Ano , Solo
19.
Nat Plants ; 5(2): 204-211, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30737514

RESUMO

During establishment of arbuscular mycorrhizal symbioses, fungal hyphae invade root cells producing transient tree-like structures, the arbuscules, where exchange of photosynthates for soil minerals occurs. Arbuscule formation and collapse lead to rapid production and degradation of plant and fungal membranes, their spatiotemporal dynamics directly influencing nutrient exchange. We determined the ultra-structural details of both membrane surfaces and the interstitial apoplastic matrix by transmission electron microscopy tomography during growth and senescence of Rhizophagus irregularis arbuscules in rice. Invasive growth of arbuscular hyphae was associated with abundant fungal membrane tubules (memtubs) and plant peri-arbuscular membrane evaginations. Similarly, the phylogenetically distant arbuscular mycorrhizal fungus, Gigaspora rosea, and the fungal maize pathogen, Ustilago maydis, developed memtubs while invading host cells, revealing structural commonalities independent of the mutualistic or parasitic outcome of the interaction. Additionally, extracellular vesicles formed continuously in the peri-arbuscular interface from arbuscule biogenesis to senescence, suggesting an involvement in inter-organismic signal and nutrient exchange throughout the arbuscule lifespan.


Assuntos
Membrana Celular/ultraestrutura , Vesículas Extracelulares/metabolismo , Micorrizas/fisiologia , Oryza/microbiologia , Células Vegetais/microbiologia , Membrana Celular/microbiologia , Tomografia com Microscopia Eletrônica , Glomeromycota/fisiologia , Hifas/fisiologia , Micorrizas/citologia , Oryza/citologia , Oryza/genética , Folhas de Planta/citologia , Folhas de Planta/microbiologia , Folhas de Planta/ultraestrutura , Raízes de Plantas/citologia , Raízes de Plantas/microbiologia , Raízes de Plantas/ultraestrutura , Plantas Geneticamente Modificadas , Simbiose , Ustilago/patogenicidade , Zea mays/microbiologia
20.
Plant Physiol ; 180(1): 465-479, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30760639

RESUMO

Most terrestrial plants form a root symbiosis with arbuscular mycorrhizal (AM) fungi, which receive fixed carbon from the plant and enhance the plant's uptake of mineral nutrients. AM symbiosis improves the phosphorous and nitrogen nutrition of host plants; however, little is known about the role of AM symbiosis in potassium (K+) nutrition. Here, we report that inoculation with the AM fungus Rhizophagus irregularis improved tomato (Solanum lycopersicum) plant growth and K+ acquisition and that K+ deficiency has a negative effect on root growth and AM colonization. Based on its homology to a Lotus japonicus AM-induced K+ transporter, we identified a mycorrhiza-specific tomato K+ transporter, SlHAK10 (Solanum lycopersicum High-affinity Potassium Transporter10), that was exclusively expressed in arbuscule-containing cells. SlHAK10 could restore a yeast K+ uptake-defective mutant in the low-affinity concentration range. Loss of function of SlHAK10 led to a significant decrease in mycorrhizal K+ uptake and AM colonization rate under low-K+ conditions but did not affect arbuscule development. Overexpressing SlHAK10 from the constitutive cauliflower mosaic virus 35S promoter or the AM-specific Solanum melongena Phosphate Transporter4 not only improved plant growth and K+ uptake but also increased AM colonization efficiency and soluble sugar content in roots supplied with low K+ Our results indicate that tomato plants have a SlHAK10-mediated mycorrhizal K+ uptake pathway and that improved plant K+ nutrition could increase carbohydrate accumulation in roots, which facilitates AM fungal colonization.


Assuntos
Glomeromycota/fisiologia , Lycopersicon esculentum/metabolismo , Micorrizas/metabolismo , Proteínas de Plantas/metabolismo , Potássio/farmacocinética , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Regulação da Expressão Gênica de Plantas , Lotus/química , Lycopersicon esculentum/crescimento & desenvolvimento , Mutação , Micorrizas/fisiologia , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Potássio/metabolismo , Simbiose , Leveduras/genética
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