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1.
Nat Commun ; 11(1): 5125, 2020 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-33046698

RESUMO

Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.


Assuntos
Fungos/genética , Genoma Fúngico , Micorrizas/genética , Simbiose , Ecossistema , Evolução Molecular , Proteínas Fúngicas/genética , Fungos/classificação , Fungos/fisiologia , Micorrizas/classificação , Micorrizas/fisiologia , Filogenia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia
2.
Ecotoxicol Environ Saf ; 205: 111350, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32961487

RESUMO

Atmospheric nitrogen dioxide (NO2) negatively affects plant (crop) growth and development, as well the yield and quality in some regions or environments. Arbuscular mycorrhizal fungus (AMF)-mediated amelioration of NO2-induced plant damage has been reported, but the underlying mechanisms remained unclear. This study explored the beneficial effect of AMF symbiosis on tomato plant responses to NO2 at physiology, biochemistry, and gene expression, with an emphasis on nitrate metabolism, antioxidative defense, and photosynthetic performance. Pot-grown plants were used in the experiments, which were performed in laboratory from February to November 2019. NO2 fumigation with a dose of 10 ± 1 ppm was carried out after 50 d of plant growth, and data were collected following 8 h of fumigation. NO2 fumigation (+NO2) and AMF inoculation (+AMF), alone and especially in combination (NO2 + AMF), increased the gene expression of nitrate- and nitrite reductase, and their enzymatic activity in leaves, such as by 61%, 27%, and 126% for the activity of nitrate reductase, and by 95%, 37%, and 188% for nitrite reductase, respectively, in +NO2, +AMF, and AMF + NO2 plants relative the control (-NO2, -AMF) levels. Following NO2 exposure, +AMF leaves displayed stronger activities of superoxide dismutase, peroxidase and catalase, and higher content of glutathione and ratio of its reduced form to oxidized form, as compared with -AMF ones. Correspondingly, lesser oxidative damage was detected in +AMF than in -AMF plants, as indicated by the contents of H2O2 and malondialdehyde, electrolyte leakage, also by in situ visualization for the formation of H2O2, superoxide anion, and dead cells. The increased antioxidative capacity in +AMF plants was correlated with enhanced expression of antioxidation-related genes. Exposure to NO2 substantially impaired photosynthetic processes in both + AMF and -AMF plants, but an obvious mitigation was observed in the former than in the latter. For example, the total chlorophyll, net photosynthetic rate, stomatal conductance, and ribulose-1,5-bisphosphate carboxylase activity were 18%, 27%, 26%, and 40% higher, respectively, in +AMF than in -AMF plants under NO2 stress. The differential photosynthetic performance was also revealed by chlorophyll fluorescence imaging. We analyzed the expression patterns of some genes related to photosynthesis and carbon metabolisms, and found that all of them exclusively presented a higher expression level in +AMF plants relative to -AMF ones under NO2 stress. Taken together, this study provided evidence that AMF symbiosis played a positively regulatory role in host plant responses to NO2, probably by increasing leaf nitrate metabolism and antioxidative defense, and maintaining the photosynthetic efficiency to some extent, wherein the transcription regulation might be a main target.


Assuntos
Lycopersicon esculentum/fisiologia , Micorrizas/fisiologia , Dióxido de Nitrogênio/toxicidade , Antioxidantes/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Micorrizas/metabolismo , Oxirredução , Fotossíntese/fisiologia , Desenvolvimento Vegetal , Folhas de Planta/metabolismo
3.
Nat Commun ; 11(1): 3897, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753587

RESUMO

Lipo-chitooligosaccharides (LCOs) are signaling molecules produced by rhizobial bacteria that trigger the nodulation process in legumes, and by some fungi that also establish symbiotic relationships with plants, notably the arbuscular and ecto mycorrhizal fungi. Here, we show that many other fungi also produce LCOs. We tested 59 species representing most fungal phyla, and found that 53 species produce LCOs that can be detected by functional assays and/or by mass spectroscopy. LCO treatment affects spore germination, branching of hyphae, pseudohyphal growth, and transcription in non-symbiotic fungi from the Ascomycete and Basidiomycete phyla. Our findings suggest that LCO production is common among fungi, and LCOs may function as signals regulating fungal growth and development.


Assuntos
Quitina/análogos & derivados , Quitina/metabolismo , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Transdução de Sinais/fisiologia , Ascomicetos/crescimento & desenvolvimento , Basidiomycota/crescimento & desenvolvimento , Ecologia , Ácidos Graxos/metabolismo , Micorrizas/fisiologia , Rhizobium/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Simbiose/fisiologia
4.
Huan Jing Ke Xue ; 41(2): 932-940, 2020 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608755

RESUMO

To investigate the effect of mycorrhizal fungi inoculation on nitrification-denitrification in the rhizospheric soil of aquatic plants, Cyperus alternifolius and Acorus tatarinowii were inoculated with the strain MF-MD obtained from local soil. Uninoculated plants served as the control group. The plants were cultivated for 3 months under nitrogen eutrophication in water, and then the nitrification and denitrification activities in the rhizospheric soil were determined. The results showed that inoculation with MF-MD promoted nitrification in the rhizospheric soil of both plants. However, MF-MD inoculation promoted denitrification in the rhizospheric soil of Cyperus alternifolius but inhibited denitrification in the rhizospheric soil of Acorus tatarinowii. The mechanism of soil nitrification-denitrification activity was analyzed by measuring the changes in the community structure of nitrifying bacteria and denitrifying bacteria in the microbial biomass of the rhizospheric soil. It was found that the rhizospheric soil microbial biomass (SMB) of the experimental group was higher than that of the control group and that the changes in the microbial community structure related to soil nitrification and denitrification differed between groups. This study contributes to an understanding of how mycorrhizal fungi combined with aquatic plants can remove N content in eutrophic water.


Assuntos
Acorus/microbiologia , Cyperus/microbiologia , Desnitrificação , Micorrizas/fisiologia , Nitrificação , Rizosfera , Organismos Aquáticos , Nitrogênio , Microbiologia do Solo
5.
PLoS One ; 15(7): e0235932, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645087

RESUMO

We tested whether post-fire seedling establishment of common boreal tree and expanding shrub species at treeline and in Arctic tundra is facilitated by co-migration of boreal forest mycorrhizal fungi. Wildfires are anticipated to facilitate biome shifts at the forest-tundra ecotone by improving seedbed conditions for recruiting boreal species; at the same time fire alters the composition and availability of mycorrhizal fungi critical to seedling performance. To determine the role of root-associated fungi (RAF) in post-fire seedling recruitment and future biome shifts, we outplanted four dominant boreal tree and shrub species inoculated with one of three treatments at treeline and in tundra: burned boreal forest, unburned boreal forest, or a control treatment of sterilized inoculum. We compared survivorship, growth, and physiological performance of the seedlings in relation to mycorrhizal inoculum treatment and among host species, characterized the RAF communities based on ITS-rDNA sequencing of individual root tips sampled from surviving seedlings, and tested for correlations between RAF composition and the inoculation treatments, host species, and duration of the experiment. We explored correlations between RAF composition and seedling metrics. Both live and sterile autoclaved inoculation treatments had similar effects on seedling survivorship and growth for all species. RAF composition did not vary by treatment, suggesting that most colonization was due to local fungi. However, seedling traits and growth were correlated with RAF species composition, colonization, and the relative abundance of specific RAF taxa. Picea sp. performance in particular showed strong co-variation with RAF metrics. Our results suggest that mycorrhizal co-migration is not a primary limiting factor to boreal seedling recruitment because the experimental provision of inoculum did not affect seedling recruitment; yet, RAF did influence seedling performance, particularly resident RAF at treeline and in tundra, suggesting that mycorrhizal fungi are important to vegetation processes at the treeline-tundra ecotone.


Assuntos
Micorrizas/fisiologia , Árvores/microbiologia , Incêndios Florestais , Basidiomycota/fisiologia , Picea/crescimento & desenvolvimento , Picea/microbiologia , Raízes de Plantas/microbiologia , Populus/crescimento & desenvolvimento , Populus/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Especificidade da Espécie , Taiga , Árvores/crescimento & desenvolvimento , Tundra
6.
Ecotoxicol Environ Saf ; 203: 110988, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678761

RESUMO

The screening and identification of hyperaccumulators is the key to the phytoremediation of soils contaminated by heavy metal (HM). Arbuscular mycorrhizal fungus (AMF) can improve plant growth and tolerance to HM; therefore, AMF-assisted phytoextraction has been regarded as a potential technique for the remediation of HM-polluted soils. A greenhouse pot experiment was conducted to determine whether Sphagneticola calendulacea is a Cd-hyperaccumulator and to investigate the effect of the AMF-Funneliformis mosseae (FM) on plant growth and on the accumulation, subcellular distribution and chemical form of Cd in S. calendulacea grown in soils supplemented with different Cd levels. At 25, 50 and 100 mg Cd kg-1 level, S. calendulacea showed high Cd tolerance, the translocation factor and the bioconcentration factor exceeded 1, and accumulation of more than 100 mg Cd kg-1 was observed in the aboveground parts of the plant, meeting the requirements for a Cd-hyperaccumulator. Moreover, FM colonization significantly increased both biomasses and Cd concentration in S. calendulacea. After FM inoculation, the Cd concentrations and proportions increased in the cell walls, but exhibited no significant change in the organelles of the shoots. Meanwhile, FM symbiosis contributed to the conversion of Cd from highly toxic chemical forms (extracted by 80% ethanol and deionized water) to less toxic chemical forms (extracted by 1 M NaCl, 2% acetic acid, 0.6 M HCl) of Cd in the shoots. Overall, S. calendulacea is a typical Cd-hyperaccumulator, and FM symbiosis relieved the phytotoxicity of Cd and promoted plant growth and Cd accumulation, and thus greatly increasing the efficiency of phytoextraction for Cd-polluted soil. Our study provides a theoretical basis and application guidance for the remediation of Cd-contaminated soil by the symbiont of S. calendulacea with FM.


Assuntos
Asteraceae/metabolismo , Bioacumulação , Cádmio/metabolismo , Glomeromycota/fisiologia , Micorrizas/fisiologia , Poluentes do Solo/metabolismo , Asteraceae/crescimento & desenvolvimento , Asteraceae/microbiologia , Biodegradação Ambiental
7.
Mol Plant Microbe Interact ; 33(10): 1177-1188, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32597696

RESUMO

Small peptides that are proteolytic cleavage products (PCPs) of less than 100 amino acids are emerging as key signaling molecules that mediate cell-to-cell communication and biological processes that occur between and within plants, fungi, and bacteria. Yet, the discovery and characterization of these molecules is largely overlooked. Today, selective enrichment and subsequent characterization by mass spectrometry-based sequencing offers the greatest potential for their comprehensive characterization, however qualitative and quantitative performance metrics are rarely captured. Herein, we addressed this need by benchmarking the performance of an enrichment strategy, optimized specifically for small PCPs, using state-of-the-art de novo-assisted peptide sequencing. As a case study, we implemented this approach to identify PCPs from different root and foliar tissues of the hybrid poplar Populus × canescens 717-1B4 in interaction with the ectomycorrhizal basidiomycete Laccaria bicolor. In total, we identified 1,660 and 2,870 Populus and L. bicolor unique PCPs, respectively. Qualitative results supported the identification of well-known PCPs, like the mature form of the photosystem II complex 5-kDa protein (approximately 3 kDa). A total of 157 PCPs were determined to be significantly more abundant in root tips with established ectomycorrhiza when compared with root tips without established ectomycorrhiza and extramatrical mycelium of L. bicolor. These PCPs mapped to 64 Populus proteins and 69 L. bicolor proteins in our database, with several of them previously implicated in biologically relevant associations between plant and fungus.


Assuntos
Laccaria/fisiologia , Peptídeos/química , Populus/química , Populus/microbiologia , Proteólise , Regulação da Expressão Gênica de Plantas , Interações entre Hospedeiro e Microrganismos , Micorrizas/fisiologia , Raízes de Plantas/química , Raízes de Plantas/microbiologia , Análise de Sequência de Proteína
8.
Ecotoxicol Environ Saf ; 201: 110869, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32585490

RESUMO

Chromium (Cr) contamination is a potential threat to the agricultural soil. Arbuscular mycorrhizal (AM) fungi have potential to remediate the heavy metal polluted soils. It was hypothesized that Cr phytoremediation potentiality of AM fungi could be enhanced in combination with saprophytic filamentous fungi and soil amendment. Tomato plants were raised in Cr polluted technosol amended with compost, inoculated with mixed-culture of AM fungi and Aspergillus terreus. It was found that, triple treatment (soil amendment with compost along with AM fungi and A. terreus inoculation) enhanced biomass production (up to 315%), fruit setting (up to 49%), photosynthetic pigments (up to 214%) and carbohydrate content (up to 400%) whereas reduced the proline (up to 76.5%), catalase (up to 34.2%), peroxidase (up to 58.9%) and root membrane permeability (up to 74.2%). The effect of AM fungi with compost amendment was additive, while it was synergistic with A. terreus. AM fungi enhanced the extraction of Cr from the substrate, but retained in the mycorrhizal root, thereby reduced the translocation into shoot and in fruit, Cr translocation was undetectable. At the end of experiment Cr content in the substrate was significantly decreased (up to 37.9%). Soil amendment with compost along with AM fungi and A. terreus inoculation can be used for reclamation of Cr polluted soils at field scale.


Assuntos
Aspergillus/fisiologia , Cromo/farmacocinética , Lycopersicon esculentum/metabolismo , Micorrizas/fisiologia , Poluentes do Solo/farmacocinética , Biodegradação Ambiental , Biomassa , Metabolismo dos Carboidratos , Catalase/metabolismo , Compostagem , Lycopersicon esculentum/enzimologia , Peroxidase/metabolismo , Raízes de Plantas/metabolismo , Prolina/metabolismo
9.
An Acad Bras Cienc ; 92 Suppl 1: e20181371, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491139

RESUMO

The formononetin biostimulant may be an option for reducing P fertilization once it stimulates mycelial growth of arbuscular mycorrhizal fungi and increases plant ability to take up nutrients through the roots, especially phosphorus. The objective of this study was to evaluate the effect of formononetin associated with phosphorus fertilization in maize. Field experiments were conducted in a randomized block design with a 3 × 4 factorial arrangement (0, 50 or 70, and 140 kg ha-1 P2O5; and formononetin application rates: 0, 25, 50, and 100 g ha-1), with four replications. Formononetin (100 g ha-1) increased the mycorrhizal colonization rate up to 30% in maize in the first four weeks after emergence when no P fertilizer was applied, and to 17% when 50 or 70 kg ha-1 of P2O5 were applied. The application of 50 and 100 g ha-1 of formononetin significantly increased plant height, ear height, and grain yield (22% - 76%) when no P fertilizer was applied. The use of formononetin in the field stimulates mycorrhizal colonization, has a positive effect on maize yield, and reduces the need for P fertilizer application in maize. However, this effect was evident only at low P soil contents.


Assuntos
Fertilizantes , Isoflavonas/farmacologia , Fósforo/análise , Solo/química , Zea mays/crescimento & desenvolvimento , Micorrizas/fisiologia , Zea mays/efeitos dos fármacos
10.
PLoS One ; 15(6): e0234546, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589642

RESUMO

Perennial crops in agricultural systems can increase sustainability and the magnitude of ecosystem services, but yield may depend upon biotic context, including soil mutualists, pathogens and cropping diversity. These biotic factors themselves may interact with abiotic factors such as drought. We tested whether perennial crop yield depended on soil microbes, water availability and crop diversity by testing monocultures and mixtures of three perennial crop species: a novel perennial grain (intermediate wheatgrass-Thinopyrum intermedium-- that produces the perennial grain Kernza®), a potential perennial oilseed crop (Silphium intregrifolium), and alfalfa (Medicago sativa). Perennial crop performance depended upon both water regime and the presence of living soil, most likely the arbuscular mycorrhizal (AM) fungi in the whole soil inoculum from a long term perennial monoculture and from an undisturbed native remnant prairie. Specifically, both Silphium and alfalfa strongly benefited from AM fungi. The presence of native prairie AM fungi had a greater benefit to Silphium in dry pots and alfalfa in wet pots than AM fungi present in the perennial monoculture soil. Kernza did not benefit from AM fungi. Crop mixtures that included Kernza overyielded, but overyielding depended upon inoculation. Specifically, mixtures with Kernza overyielded most strongly in sterile soil as Kernza compensated for poor growth of Silphium and alfalfa. This study identifies the importance of soil biota and the context dependence of benefits of native microbes and the overyielding of mixtures in perennial crops.


Assuntos
Agricultura , Medicago sativa/fisiologia , Plantas Daninhas/crescimento & desenvolvimento , Estresse Fisiológico/fisiologia , Biota/fisiologia , Produtos Agrícolas/fisiologia , Ecossistema , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/microbiologia , Micorrizas/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Microbiologia do Solo , Simbiose/fisiologia
11.
PLoS One ; 15(6): e0234410, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32516341

RESUMO

The Eupatorium adenophorum have widespread invaded the karst ecosystem of southwest China and threatened the regional native community stability. Arbuscular mycorrhizae (AM) plays an important role in promoting growth for host plants via root external mycelia. However, whether AM regulates plant root traits underlying competition between invasive and native species via mycorrhizal networks in karst habitats, remains unclear. An experiment was conducted in a microcosm composed of two planting compartments flanking a competition compartment. The invasive E. adenophorum and native Artemisia annua were each placed in one of the two planting compartments with or without Glomus etunicatum fungus. The nutrient access treatments included the competitive utilization (Cu), single utilization (Su) and non-utilization (Nu) by using different nylon meshes allowed or prevented mycelium passing to acquire nutrients from the competition compartment. Root traits and nutrients of the two species were analyzed. The results showed that AM fungi had differential effects on root traits and nutrients of E. adenophorum and A. annua seedlings, which increased dry weight, length, surface area, volume, tips and branching points in roots, specific root length and volume, root nitrogen (N) and phosphorus (P) contents under Cu, Su and Nu treatments. AM fungus was also associated with decreases in the average diameter for both species. Under the Cu treatment, E. adenophorum had significantly greater length, surface area, volume, tips and branching points of roots, specific root traits, and root N and P than A. annua. AM fungi changed root phenotypes and nutrient uptake for both invasive and native plant species via interconnected mycorrhizal networks. Overall, our results suggest that through mycorrhizal networks, the invasive plant experiences greater benefits than the native plant in the nutrient competition, which fosters root morphological developments in karst soil.


Assuntos
Ageratina/metabolismo , Micorrizas/metabolismo , Microbiologia do Solo , Artemisia annua/metabolismo , China , Ecossistema , Micélio , Micorrizas/fisiologia , Nitrogênio , Nutrientes , Fósforo , Raízes de Plantas/crescimento & desenvolvimento , Plantas Daninhas/metabolismo , Solo , Árvores/crescimento & desenvolvimento
12.
PLoS One ; 15(6): e0229807, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32502167

RESUMO

The success of tree recruitment in Mediterranean holm oak (Quercus ilex) forests is threatened by the increasing intensity, duration and frequency of drought periods. Seedling germination and growth are modulated by complex interactions between abiotic (microhabitat conditions) and biotic factors (mycorrhiza association) that may mitigate the impacts of climate change on tree recruitment. To better understand and anticipate these effects, we conducted a germination experiment in a long-term precipitation reduction (PR) field experiment where we monitored seedling establishment and survival, micro-habitat conditions and ectomycorrhizal (ECM) colonization by different mycelia exploration types during the first year of seedling growth. We hypothesized that (i) the PR treatment decreases seedling survival relative to the control with ambient conditions, (ii) microhabitat conditions of water and light availability are better predictors of seedling survival than the PR treatment, (iii) the PR treatment will favour the development of ECM exploration types with drought-resistance traits such as differentiated rhizomorphs. Contrary to our first hypothesis, seedling survival was lower in control plots with overall higher soil moisture. Micro-habitat light and soil moisture conditions were better predictors of seedling survival and growth than the plot-level PR treatment, confirming our second hypothesis. Furthermore, in line with our third hypothesis, we found that ECM with longer extramatrical mycelia were more abundant in the PR treatment plots and were positively correlated to survival, which suggests a potential role of this ECM exploration type in seedling survival and recruitment. Although summer drought was the main cause of seedling mortality, our study indicates that drier conditions in spring can increase seedling survival, presumably through a synergistic effect of drought adapted ECM species and less favourable conditions for root pathogens.


Assuntos
Secas , Ecossistema , Micorrizas/fisiologia , Quercus/crescimento & desenvolvimento , Quercus/microbiologia , Plântula/microbiologia , Plântula/fisiologia , Germinação , Análise de Sobrevida
13.
Proc Natl Acad Sci U S A ; 117(28): 16649-16659, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32586957

RESUMO

Low availability of nitrogen (N) is often a major limiting factor to crop yield in most nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most land plants that enhance plant nutrient uptake, particularly of phosphate. A growing number of reports point to the substantially increased N accumulation in many mycorrhizal plants; however, the contribution of AM symbiosis to plant N nutrition and the mechanisms underlying the AM-mediated N acquisition are still in the early stages of being understood. Here, we report that inoculation with AM fungus Rhizophagus irregularis remarkably promoted rice (Oryza sativa) growth and N acquisition, and about 42% of the overall N acquired by rice roots could be delivered via the symbiotic route under N-NO3 - supply condition. Mycorrhizal colonization strongly induced expression of the putative nitrate transporter gene OsNPF4.5 in rice roots, and its orthologs ZmNPF4.5 in Zea mays and SbNPF4.5 in Sorghum bicolor OsNPF4.5 is exclusively expressed in the cells containing arbuscules and displayed a low-affinity NO3 - transport activity when expressed in Xenopus laevis oocytes. Moreover, knockout of OsNPF4.5 resulted in a 45% decrease in symbiotic N uptake and a significant reduction in arbuscule incidence when NO3 - was supplied as an N source. Based on our results, we propose that the NPF4.5 plays a key role in mycorrhizal NO3 - acquisition, a symbiotic N uptake route that might be highly conserved in gramineous species.


Assuntos
Proteínas de Transporte de Ânions/metabolismo , Glomeromycota/fisiologia , Micorrizas/fisiologia , Nitrogênio/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Transporte de Ânions/genética , Regulação da Expressão Gênica de Plantas , Nitratos/metabolismo , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Sorghum/genética , Sorghum/metabolismo , Sorghum/microbiologia , Zea mays/genética , Zea mays/metabolismo , Zea mays/microbiologia
14.
Nat Commun ; 11(1): 2114, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32355217

RESUMO

Most plants associate with beneficial arbuscular mycorrhizal (AM) fungi that facilitate soil nutrient acquisition. Prior to contact, partner recognition triggers reciprocal genetic remodelling to enable colonisation. The plant Dwarf14-Like (D14L) receptor conditions pre-symbiotic perception of AM fungi, and also detects the smoke constituent karrikin. D14L-dependent signalling mechanisms, underpinning AM symbiosis are unknown. Here, we present the identification of a negative regulator from rice, which operates downstream of the D14L receptor, corresponding to the homologue of the Arabidopsis thaliana Suppressor of MAX2-1 (AtSMAX1) that functions in karrikin signalling. We demonstrate that rice SMAX1 is a suppressor of AM symbiosis, negatively regulating fungal colonisation and transcription of crucial signalling components and conserved symbiosis genes. Similarly, rice SMAX1 negatively controls strigolactone biosynthesis, demonstrating an unexpected crosstalk between the strigolactone and karrikin signalling pathways. We conclude that removal of SMAX1, resulting from D14L signalling activation, de-represses essential symbiotic programmes and increases strigolactone hormone production.


Assuntos
Proteínas de Arabidopsis/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Micorrizas/fisiologia , Oryza/microbiologia , Proteínas de Plantas/fisiologia , Simbiose , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Furanos/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Compostos Heterocíclicos com 3 Anéis/metabolismo , Homozigoto , Peptídeos e Proteínas de Sinalização Intracelular/genética , Lactonas/metabolismo , Família Multigênica , Oryza/genética , Filogenia , Proteínas de Plantas/genética , Raízes de Plantas/microbiologia , Piranos/metabolismo , RNA-Seq , Transdução de Sinais
15.
Nat Commun ; 11(1): 2204, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32371877

RESUMO

Empirical studies show that plant-soil feedbacks (PSF) can generate negative density dependent (NDD) recruitment capable of maintaining plant community diversity at landscape scales. However, the observation that common plants often exhibit relatively weaker NDD than rare plants at local scales is difficult to reconcile with the maintenance of overall plant diversity. We develop a spatially explicit simulation model that tracks the community dynamics of microbial mutualists, pathogens, and their plant hosts. We find that net PSF effects vary as a function of both host abundance and key microbial traits (e.g., host affinity) in ways that are compatible with both common plants exhibiting relatively weaker local NDD, while promoting overall species diversity. The model generates a series of testable predictions linking key microbial traits and the relative abundance of host species, to the strength and scale of PSF and overall plant community diversity.


Assuntos
Ecossistema , Micorrizas/fisiologia , Plantas/metabolismo , Microbiologia do Solo , Solo/química , Simbiose/fisiologia , Algoritmos , Retroalimentação Fisiológica/fisiologia , Interações entre Hospedeiro e Microrganismos , Modelos Teóricos , Micorrizas/classificação , Plantas/classificação , Plantas/microbiologia , Especificidade da Espécie
16.
Proc Biol Sci ; 287(1927): 20200483, 2020 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-32453987

RESUMO

Nitrogen addition affects plant-arbuscular mycorrhizal fungi (AMF) association greatly. However, although the direct effect of nitrogen addition on AMF colonization has received investigation, its indirect effect through shifts in plant community composition has never been quantified. Based on a 7-year nitrogen addition experiment in an alpine meadow of Qinghai-Tibet Plateau, we investigated the effects of nitrogen addition on plant community, AMF diversity and colonization, and disentangled the direct and indirect effects of nitrogen addition on community AMF colonization. At plant species level, nitrogen addition significantly decreased root colonization rate and altered AMF community composition, but with no significant effect on AMF richness. At plant community level, plant species richness and AMF colonization rate decreased with nitrogen addition. Plant species increasing in abundance after nitrogen addition were those with higher AMF colonization rates in natural conditions, resulting in an increased indirect effect induced by alternation in plant community composition with nitrogen addition, whereas the direct effect was negative and decreased with nitrogen addition. Overall, we illustrate the effect of nitrogen addition and plant species in influencing the AMF diversity, demonstrate how shifts in plant community composition (indirect effect) weaken the negative direct effect of nitrogen addition on community-level AMF colonization rate, and emphasize the importance of plant community-mediated mechanisms in regulating ecosystem functions.


Assuntos
Micorrizas/fisiologia , Plantas/microbiologia , Ecossistema , Nitrogênio , Raízes de Plantas/microbiologia , Microbiologia do Solo
17.
Chemosphere ; 256: 127046, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32438129

RESUMO

Although it was well known that arbuscular mycorrhizal fungus (AMF) inoculation significantly increased atrazine dissipation in the soil, the effect of AMF on bacterial community, especially potential atrazine-degrading bacteria mediating atrazine dissipation has been overlooked. In the present study, there were four different treatments: Funnelliformis mosseae inoculation with or without atrazine; and non-AMF inoculation with or without atrazine. F. mosseae significantly increased atrazine dissipation rate from 28.7% to 53.3%. Then 16S rRNA gene sequencing results indicated that bacteria community differed significantly by F. mosseae inoculation and atrazine addition. The Shannon index decreased significantly with AMF and atrazine at phylum and family level, and significant inhibition of atrazine on evenness was also observed. LEFSe analysis revealed that Terrimonas and Arthrobacter were significantly associated with F. mosseae, as well as unidentified_Nitrospiraceae associated with atrazine addition. There are several bacterial taxa associated with both F. mosseae inoculation and atrazine addition. Totally, twelve atrazine-degrading bacterial genera (>0.10%) were identified. When atrazine was added, the abundance of Arthrobacter, Burkholderia, Mycobacterium and Streptomyces increased in F. mosseae inoculation treatment, but Nocardioides, Pseudomonas, Bradyrhizobium, Rhizobium, Rhodobacter, Methylobacterium, Bosea and Shinella decreased. In the presence of atrazine, activities of dehydrogenase, urease, acid and alkaline phosphatase in F. mosseae inoculation treatment were significantly higher than those in non-inoculation. However, there was no significant relationship between bacterial community and any soil enzyme activity in four treatments. Our findings reveal the potential relationship between soil bacterial community and AMF inoculation during atrazine dissipation.


Assuntos
Atrazina/toxicidade , Herbicidas/toxicidade , Micorrizas/fisiologia , Microbiologia do Solo , Bactérias/efeitos dos fármacos , Glomeromycota/fisiologia , Raízes de Plantas/efeitos dos fármacos , RNA Ribossômico 16S , Solo
18.
PLoS One ; 15(5): e0233878, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470094

RESUMO

The present study aimed to investigate the effects of arbuscular mycorrhizal (AM) fungal communities originating from organic and conventional agriculture on wheat growth and yield. Six different spring wheat cultivars released in different years in north and central European countries were considered. We hypothesised that AM fungal inoculum collected from organic agricultural fields would elicit a greater positive growth response than inoculum collected from conventional agricultural fields; and that older cultivars, which were developed under conditions of low fertilizer input, would exhibit overall greater growth responses to the presence of AM fungi, compared with more recent cultivars, and that AM fungal inoculum from conventional fields might have the most beneficial effect on the growth and yield of recent cultivars. The results showed that the overall effects on the growth and yield of spring wheat grown with organic and conventional AM fungal inocula did not differ greatly. However, the inoculation growth response, showing the difference of the effects of organic and conventional inocula, varied between particular wheat cultivars. Inoculation growth response of the cultivar Pikker (released in 1959) was the most positive, while that of the cultivar Arabella (released in 2012) was the most negative. The use of AM fungal inoculum from organic fields resulted in slightly taller plant individuals. Pikker showed relatively higher yield and stronger growth when the organic AM fungal inoculum was used. Arabella exhibited relatively lower yield and weaker growth when the organic inoculum was used. Whether the positive response of Pikker to Estonian organic inoculation reflects adaptation to the locally occurring AM fungal community needs to be established by further studies of the communities of AM fungi colonizing wheat roots.


Assuntos
Fazendas , Micorrizas/fisiologia , Agricultura Orgânica , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Raízes de Plantas/fisiologia , Brotos de Planta/fisiologia , Solo , Microbiologia do Solo , Triticum/anatomia & histologia
19.
Nat Commun ; 11(1): 2636, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32457288

RESUMO

The mechanisms regulating community composition and local dominance of trees in species-rich forests are poorly resolved, but the importance of interactions with soil microbes is increasingly acknowledged. Here, we show that tree seedlings that interact via root-associated fungal hyphae with soils beneath neighbouring adult trees grow faster and have greater survival than seedlings that are isolated from external fungal mycelia, but these effects are observed for species possessing ectomycorrhizas (ECM) and not arbuscular mycorrhizal (AM) fungi. Moreover, survival of naturally-regenerating AM seedlings over ten years is negatively related to the density of surrounding conspecific plants, while survival of ECM tree seedlings displays positive density dependence over this interval, and AM seedling roots contain greater abundance of pathogenic fungi than roots of ECM seedlings. Our findings show that neighbourhood interactions mediated by beneficial and pathogenic soil fungi regulate plant demography and community structure in hyperdiverse forests.


Assuntos
Micorrizas/fisiologia , Microbiologia do Solo , Árvores/microbiologia , China , Florestas , Fungos/genética , Fungos/patogenicidade , Fungos/fisiologia , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Modelos Biológicos , Biologia Molecular , Micorrizas/genética , Micorrizas/patogenicidade , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Simbiose , Árvores/crescimento & desenvolvimento
20.
Ecotoxicol Environ Saf ; 196: 110537, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32272346

RESUMO

The objective of the study was to explore the influences of arbuscular mycorrhizae (AM), phosphorus (P) fertiliser, biochar application (BC) and their interactions on Medicago sativa growth, nutrient, Cd content and AM fungi-plant symbioses. Applications of both P fertiliser and BC significantly increased total biomass and P and potassium (K) uptake, regardless of AM. When no P fertiliser or BC was used, the shoot biomass and nitrogen (N), P, and K contents in the +AM treatments were 1.39, 1.54, 4.53 and 2.06 times higher than those in the -AM treatments, respectively. AM fungi only elevated the total P uptake by 44.03% when P fertiliser was applied at a rate of 30 mg P kg-1 in the absence of BC addition. With BC application or high-P fertiliser input (100 mg P kg-1), the soil available P was significantly higher than that in the other treatments, and AM fungi significantly reduced the shoot biomass. The minimum Cd concentration occurred in the shoots of alfalfas treated with BC and high-P fertiliser inputs; this concentration was lower than the maximum permitted concentration in China. Although the BC and high-P inputs could eliminate the positive mycorrhizal response, the results suggested that BC application in combination with high-P fertiliser input could not only increase forage yields but also lower Cd concentrations to meet the forage safety standards by the dilution effect.


Assuntos
Cádmio/metabolismo , Carvão Vegetal/farmacologia , Medicago sativa/crescimento & desenvolvimento , Micorrizas/fisiologia , Fósforo/farmacologia , Biomassa , Carvão Vegetal/análise , Fertilizantes/análise , Medicago sativa/efeitos dos fármacos , Medicago sativa/metabolismo , Medicago sativa/microbiologia , Nutrientes/metabolismo , Fósforo/análise , Fósforo/metabolismo , Poluentes do Solo/metabolismo , Simbiose/efeitos dos fármacos
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