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1.
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
2.
Ecotoxicol Environ Saf ; 201: 110816, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521370

RESUMO

Mine tailings contain dangerously high levels of toxic metals which pose a constant threat to local ecosystems. Few naturally grown native plants can colonize tailings site and the existence of their root-associated microbial populations is poorly understood. The objective of this study was to give further insights into the interactions between native plants and their microbiota during natural attenuation of abandoned V-Ti magnetite mine tailings. In the present work, we first examined the native plants' potential for phytoremediation using plant/soil analytical methods and then investigated the root microbial communities and their inferred functions using 16 S rRNA-based metagenomics. It was found that in V-Ti magnetite mine tailings the two dominant plants Bothriochloa ischaemum and Typha angustifolia were able to increase available nitrogen in the rhizosphere soil by 23.3% and 53.7% respectively. The translocation factors (TF) for both plants indicated that B. ischaemum was able to accumulate Pb (TF = 1.212), while T. angustifolia was an accumulator of Mn (TF = 2.502). The microbial community structure was more complex in the soil associated with T. angustifolia than with B. ischaemum. The presence of both plants significantly reduced the population of Acinetobacter. Specifically, B. ischaemum enriched Massilia, Opitutus and Hydrogenophaga species while T. angustifolia significantly increased rhizobia species. Multivariate analyses revealed that among all tested soil variables Fe and total organic carbon (TOC) could be the key factors in shaping the microbial structure. The putative functional analysis indicated that soil sample of B. ischaemum was abundant with nitrate/nitrite reduction-related functions while that of T. angustifolia was rich in nitrogen fixing functions. The results indicate that these native plants host a diverse range of soil microbes, whose community structure can be shaped by plant types and soil variables. It is also possible that these plants can be used to improve soil nitrogen content and serve as bioaccumulators for Pb or Mn for phytoremediation purposes.


Assuntos
Óxido Ferroso-Férrico/toxicidade , Microbiota/efeitos dos fármacos , Raízes de Plantas/microbiologia , Poluentes do Solo/toxicidade , Titânio/toxicidade , Vanádio/toxicidade , Biodegradação Ambiental , China , Óxido Ferroso-Férrico/análise , Metagenômica , Microbiota/genética , Mineração , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Rhizobium , Rizosfera , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Titânio/análise , Typhaceae/crescimento & desenvolvimento , Typhaceae/microbiologia , Vanádio/análise
3.
PLoS Negl Trop Dis ; 14(5): e0008228, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32463813

RESUMO

BACKGROUND: Mycobacterium ulcerans is an environmental mycobacterium responsible for an opportunistic, noncontagious tropical infection named Buruli ulcer that necrotizes the skin and the subcutaneous tissues. M. ulcerans is thought to penetrate through breached skin after contact with contaminated wetland environments, yet the exact biotopes where M. ulcerans occurs remain elusive, hence obscuring the epidemiological chain of transmission of this opportunistic pathogen. METHODOLOGY/PRINCIPAL FINDINGS: Polymerase chain reaction investigations detected M. ulcerans in 39/46 (84.7%) rhizosphere specimens collected in 13 Buruli ulcer-endemic areas in Côte d'Ivoire and 3/20 (15%) specimens collected in a nonendemic area (P = 5.73.E-7); only 3/63 (4.7%) sediment specimens from sediment surrounding the rhizospheres were positive in endemic area (P = 6.51.E-12). High-throughput sequencing further detected three PCR-positive plants, Croton hirtus, Corton kongensis and Oriza sativa var. japonica (rice), in the rectal content of two M. ulcerans-positive wild Thryonomys swinderianus grasscutters that were hunted in Buruli ulcer-endemic areas, while no PCR-positive plants were detected in the rectal content of two negative control animals that were farmed in a nonendemic area. CONCLUSIONS/SIGNIFICANCE: Our data suggest an alimentary chain of transmission of M. ulcerans from plants to T. swinderianus grasscutters and people that utilize T. swinderianus as bush meat in Buruli ulcer-endemic areas in Côte d'Ivoire. Guidance to adopt protective measures and avoid any direct contact with potentially contaminated rhizospheres and with grasscutter intestinal content when preparing the animals for cooking should be established for at-risk populations.


Assuntos
Úlcera de Buruli/microbiologia , Úlcera de Buruli/transmissão , Mycobacterium ulcerans/isolamento & purificação , Animais , Úlcera de Buruli/epidemiologia , Costa do Marfim/epidemiologia , Croton/microbiologia , Fezes/microbiologia , Sedimentos Geológicos/microbiologia , Humanos , Mycobacterium ulcerans/classificação , Mycobacterium ulcerans/genética , Mycobacterium ulcerans/fisiologia , Saúde Única , Poaceae/microbiologia , Roedores/microbiologia , Zoonoses/microbiologia , Zoonoses/transmissão
4.
Ecotoxicol Environ Saf ; 194: 110366, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32126413

RESUMO

Haloxyfop-R-methyl (haloxyfop) can efficiently control Spartina alterniflora in coastal ecosystems, but its effect on soil microbial communities is not known. In the present study, the impact of the haloxyfop on rhizosphere soil bacterial communities of S. alterniflora over the dissipation process of the herbicide has been studied in a coastal wetland. The response of the bacterial community in the rhizoplane (iron plaque) of S. alterniflora subjected to haloxyfop treatment was also investigated. Results showed that the persistence of haloxyfop in the rhizosphere soil followed an exponential decay with a half-life of 2.6-4.9 days, and almost all of the haloxyfop dissipated on Day 30. The diversity of rhizosphere soil bacteria was decreased at the early stages (Days 1, 3 & 7) and recovered at late stages (Days 15 & 30) of the haloxyfop treatment. Application of haloxyfop treatment increased the relative abundance of the genera Pseudomonas, Acinetobacter, Pontibacter, Shewanella and Aeromonas. Strains isolated from these genera can degrade herbicides efficiently, which possibly played a role in the degradation of haloxyfop. The rhizoplane bacterial diversity was reduced on Day 15 while being vastly enhanced on Day 30. Soil variables, including the electric conductivity, redox potential, and soil moisture, along with the soil haloxyfop residue, jointly shape the bacterial community in rhizosphere soil.


Assuntos
Herbicidas/toxicidade , Microbiota/efeitos dos fármacos , Piridinas/toxicidade , Rizosfera , Microbiologia do Solo , Bactérias/metabolismo , Herbicidas/metabolismo , Poaceae/microbiologia , Solo/química , Áreas Alagadas
5.
PLoS One ; 15(3): e0229887, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32119709

RESUMO

The objective of the present study was to characterize the rumen bacterial and archaeal communities in dairy cows fed different ratios of maize silage (MS) and grass silage (GS), and place the findings in the context of ruminal fermentation as well as previously reported methane (CH4) emissions. Rumen fluid from 12 rumen cannulated dairy cows was collected after 10 and 17 days of feeding one of four diets, all of which had the same roughage to concentrate ratio of 80:20 based on dry matter (DM). Roughage in the four diets (GS100, GS0, GS67, GS33) consisted of either 1000 g/kg DM GS (GS100), 1000 g/kg DM MS (GS0), or a mixture of both silages in different proportions [667 g/kg DM GS and 333 g/kg DM MS (GS67); 333 g/kg DM GS and 677 g/kg DM MS (GS33)]. Total volatile fatty acid (VFA) concentrations and the molar proportions of the ruminal VFA were not affected by diet. Only the molar proportion of isovalerate was affected by time, being lower on day 17 than on day 10. Bacterial and archaeal concentrations were not affected by diet but increased from day 10 to day 17. The bacterial community composition was affected by diet, time and diet × time, whereas the archaeal community composition was only affected by diet. Several bacterial and archaeal genus level groups were associated with diet, but not with time. Analysis indicated the increased use of hydrogen by succinate and lactate producing bacteria is likely to at least partially explain the previously reported lower CH4 emissions from MS fed dairy cows. Furthermore, time had a significant effect on both bacterial and archaeal concentrations, and also bacterial community composition. This indicates that the rumen microbiota had not stabilized after 10 days of feeding the experimental diets.


Assuntos
Microbioma Gastrointestinal , Poaceae/metabolismo , Rúmen/microbiologia , Silagem/microbiologia , Zea mays/metabolismo , Animais , Archaea/metabolismo , Bovinos , Dieta , Digestão/fisiologia , Fermentação , Leite/microbiologia , Poaceae/microbiologia , Rúmen/metabolismo , Zea mays/microbiologia
6.
Ecotoxicol Environ Saf ; 192: 110299, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32058165

RESUMO

Arbuscular mycorrhizal fungi (AMF) are ubiquitous, obligatory plant symbionts that have a beneficial influence on plants in contaminated environments. This study focused on evaluating the biomass and biodiversity of the AMF and microbial communities associated with Poa trivialis and Phragmites australis plants sampled at an aged site contaminated with phenol and polynuclear aromatic hydrocarbons (PAHs) and an uncontaminated control site. We analyzed the soil phospholipid fatty acid profile to describe the general structure of microbial communities. PCR-denaturing gradient gel electrophoresis with primers targeting the 18S ribosomal RNA gene was used to characterize the biodiversity of the AMF communities and identify dominant AMF species associated with the host plants in the polluted and control environments. The root mycorrhizal colonization and AMF biomass in the soil were negatively affected by the presence of PAHs and phenol, with no significant differences between the studied plant species, whereas the biodiversity of the AMF communities were influenced by the soil contamination and plant species. Soil contamination was more detrimental to the biodiversity of AMF communities associated with Ph. australis, compared to P. trivialis. Both species favored the development of different AMF species, which might be related to the specific features of their different root systems and soil microbial communities. The contaminated site was dominated by AMF generalists like Funneliformis and Rhizophagus, whereas in the control site Dominikia, Archaeospora, Claroideoglomus, Glomus, and Diversispora were also detected.


Assuntos
Micorrizas/isolamento & purificação , Fenol/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Microbiologia do Solo , Poluentes do Solo/análise , Biodiversidade , Biomassa , Especificidade de Hospedeiro , Micorrizas/classificação , Micorrizas/genética , Micorrizas/crescimento & desenvolvimento , Poaceae/classificação , Poaceae/microbiologia , Solo/química
7.
Environ Pollut ; 261: 114201, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32109819

RESUMO

Microbiota in urban green spaces underpin ecosystem services that are essential to environmental health and human wellbeing. However, the factors shaping the microbial communities in urban green spaces, especially those associated with turf grass phyllosphere, remain poorly understood. The lack of this knowledge greatly limits our ability to assess ecological, social and recreational benefits of urban green spaces in the context of global urbanization. In this study, we used amplicon sequencing to characterize soil and grass phyllosphere bacterial communities in 40 urban green spaces and three minimally disturbed national parks in Victoria, Australia. The results indicated that urbanization might have shown different impacts on soil and grass phyllosphere microbial communities. The bacterial diversity in soil but not in grass phyllosphere was significantly higher in urban green spaces than in national parks. Principal coordinate analysis revealed significant differences in the overall patterns of bacterial community composition between urban green spaces and national parks for both soil and grass phyllosphere. Industrial development, as represented by the number of industries in the region, was identified as a key driver shaping the bacterial community profiles in urban green spaces. Variation partitioning analysis suggested that industrial factors together with their interaction with other factors explained 20% and 28% of the variances in soil and grass phyllosphere bacterial communities, respectively. The findings highlight the importance of industrial development in driving the spatial patterns of urban microbiomes, and have important implication for the management of microbiomes in urban green spaces.


Assuntos
Desenvolvimento Industrial , Microbiota , Poaceae , Microbiologia do Solo , Microbiota/fisiologia , Poaceae/microbiologia , Solo/química , População Urbana , Vitória
8.
Arch Microbiol ; 202(5): 1157-1171, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32067064

RESUMO

Soil microbes play important roles in plant growth and in the biogeochemical cycling of earth's elements. However, the structure and functions of the microbial community associated with the growth of second-generation energy crops, such as Miscanthus, remain unclear. Thus, in this study, the composition and function of the bacterial and fungal communities associated with Miscanthus cultivation were analyzed by MiSeq sequencing combined with PICRUSt and FUNGUIld analyses. The results of community composition and diversity index analyses showed that Miscanthus cultivation significantly altered the bacterial and fungal community composition and reduced bacterial and fungal diversity. In addition, Miscanthus cultivation increased the soil organic matter (SOM) and total nitrogen (TN) contents. The correlation analysis between microbial community composition and environmental factors indicated that SOM and TN were the most important factors affecting bacterial and fungal communities. Miscanthus cultivation could enrich the abundances of Pseudomonas, Rhizobium, Luteibacter, Bradyrhizobium, Phenylobacterium and other common plant-promoting bacteria, while also increasing Cladophialophora, Hymenula, Magnaporthe, Mariannaea, etc., which predicted corresponded to the saprotrophic, plant pathogenic, and pathotrophic trophic modes. The PICRUSt predictive analysis indicated that Miscanthus cultivation altered the metabolic capabilities of bacterial communities, including the metabolism of carbon, nitrogen, and phosphorus cycle. In addition, FUNGUIld analysis indicated that Miscanthus cultivation altered the fungal trophic mode. The effects of Miscanthus on the communities and function of bacteria and fungi varied among Miscanthus species. Miscanthus specie Xiangdi NO 1 had the greatest impact on soil bacterial and fungal communities, whereas Miscanthus specie Wujiemang NO 1 had the greatest impact on soil bacteria and fungi functions. The results of this study provide a reference for the composition and function of microbial communities during the growth of Miscanthus.


Assuntos
Bactérias/genética , Fungos/genética , Microbiota/fisiologia , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Rizosfera , Microbiologia do Solo , Agricultura , Sequenciamento de Nucleotídeos em Larga Escala , Solo/química
9.
PLoS One ; 15(1): e0228202, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31999724

RESUMO

The use of perennial crop species in agricultural systems may increase ecosystem services and sustainability. Because soil microbial communities play a major role in many processes on which ecosystem services and sustainability depend, characterization of soil community structure in novel perennial crop systems is necessary to understand potential shifts in function and crop responses. Here, we characterized soil fungal community composition at two depths (0-10 and 10-30 cm) in replicated, long-term plots containing one of three different cropping systems: a tilled three-crop rotation of annual crops, a novel perennial crop monoculture (Intermediate wheatgrass, which produces the grain Kernza®), and a native prairie reconstruction. The overall fungal community was similar under the perennial monoculture and native vegetation, but both were distinct from those in annual agriculture. The mutualist and saprotrophic community subsets mirrored differences of the overall community, but pathogens were similar among cropping systems. Depth structured overall communities as well as each functional group subset. These results reinforce studies showing strong effects of tillage and sampling depth on soil community structure and suggest plant species diversity may play a weaker role. Similarities in the overall and functional fungal communities between the perennial monoculture and native vegetation suggest Kernza® cropping systems have the potential to mimic reconstructed natural systems.


Assuntos
Produção Agrícola , Micobioma , Poaceae/crescimento & desenvolvimento , Microbiologia do Solo , Produção Agrícola/métodos , Fungos/classificação , Fungos/isolamento & purificação , Poaceae/microbiologia
10.
Int J Syst Evol Microbiol ; 70(3): 1843-1849, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31951191

RESUMO

A novel bacterial strain, designated AK13T (=KACC 21401T=DSM 109981T), was isolated from the rhizosphere of Miscanthus sacchariflorus. Strain AK13T was found to be an aerobic, Gram-stain-positive, endospore-forming and rod-shaped bacterium. It formed yellow circular colonies with smooth convex surfaces. The genomic DNA G+C content of strain AK13T was estimated to be 40 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that this strain was most closely related to Bacillus lehensis MLB2T (99.4 %), Bacillus oshimensis K11T (98.8 %) and Bacillus patagoniensis PAT 05T (96.6 %). The average nucleotide identity values between strain AK13T and B. lehensis MLB2T, B. oshimensis K11T and B. patagoniensis PAT 05T were 90.93, 91.05 and 71.87 %, respectively, with the digital DNA-DNA hybridization values of 42.7, 42.6 and 18.8 %, respectively. Cells grew at 5-40 °C (optimum, 28-35 °C), pH 6.5-13 (optimum, pH 8-9) and in the presence of 0-13.0 % (w/v) NaCl (optimum, 1 %). The cell wall of strain AK13T contained meso-diaminopimelic acid, and the major isoprenoid quinone was MK-7. Results of fatty acid methyl ester analysis revealed that iso-C15 : 0 was the predominant cellular fatty acid. Two-dimensional thin-layer chromatography analysis indicated that the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and glycolipid. The genotypic and phenotypic characteristics suggested that strain AK13T represented a novel species of the genus Bacillus, and thus the name Bacillus miscanthi sp. nov. is proposed.


Assuntos
Bacillus/classificação , Filogenia , Poaceae/microbiologia , Rizosfera , Microbiologia do Solo , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
11.
J Agric Food Chem ; 68(5): 1169-1185, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31922733

RESUMO

Epichloë endophytes in forage grasses have attracted widespread attention and interest of chemistry researchers as a result of the various unique chemical structures and interesting biological activities of their secondary metabolites. This review describes the diversity of unique chemical structures of taxa from Epichloë endophytes and grass infected with Epichloë endophytes and demonstrates their reported biological activities. Until now, nearly 160 secondary metabolites (alkaloids, peptides, indole derivatives, pyrimidines, sesquiterpenoids, flavonoids, phenol and phenolic acid derivatives, aliphatic metabolites, sterols, amines and amides, and others) have been reported from Epichloë endophytes and grass infected with Epichloë endophytes. Among these, non-alkaloids account for half of the population of total metabolites, indicating that they also play an important role in Epichloë endophytes and grass infected with Epichloë endophytes. Also, a diverse array of secondary metabolites isolated from Epichloë endophytes and symbionts is a rich source for developing new pesticides and drugs. Bioassays disclose that, in addition to toxic alkaloids, the other metabolites isolated from Epichloë endophytes and symbionts have notable biological activities, such as antifungal, anti-insect, and phytotoxic activities. Accordingly, the biological functions of non-alkaloids should not be neglected in the future investigation of Epichloë endophytes and symbionts.


Assuntos
Alcaloides/metabolismo , Endófitos/química , Epichloe/química , Poaceae/microbiologia , Simbiose , Alcaloides/química , Alcaloides/toxicidade , Animais , Endófitos/fisiologia , Epichloe/metabolismo , Insetos/efeitos dos fármacos , Gado/metabolismo , Poaceae/fisiologia
12.
Chemosphere ; 243: 125353, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31765899

RESUMO

Here we compared the performance of four macrophytes namely Brachia mutica, Typha domingensis, Phragmites australis and Leptochala fusca, in bacterially assisted floating treatment wetlands (FTWs) for the clean-up of five trace metals (Fe, Mn, Ni, Pb, and Cr) from polluted river water. The river water was artificially spiked with reagent grade chemicals to increase the trace metal pollution. The macrophytes were planted in a polystyrene sheet to prepare FTWs, which were placed over the metal-contaminated river water. The consortium of five rhizospheric and endophytic bacterial strains, i.e., Aeromonas salmonicida, Pseudomonas indoloxydans, Bacillus cerus, Pseudomonas gessardii, and Rhodococcus sp., was inoculated support the natural remediation ability. We found a significant reduction in the metal content by all four macrophytes and the removal was significantly enhanced when bacterial inoculum was applied. The maximum removal was observed in FTWs planted with P. australis and inoculated with bacteria. In this treatment (T6) the Fe, Mn, Ni, Pb and Cr contents were reduced to 0.53, 0.20, 0.09, 1.04 and 0.07 mg L-1 after five weeks retention time. The bacterial inoculation sufficiently increased the plant biomass. All macrophytes depicted potential to uptake and translocate trace metals in the roots instead of shoots. The bacterial inoculation acclimatize the plants roots followed by shoots and enhanced the uptake of metals by macrophytes. This study emphasized the usefulness of macrophytes-bacteria mutualism in FTWs system for the remediation of trace metals. The similar systems may provide practical solutions for the remediation of trace metals of polluted river water.


Assuntos
Biodegradação Ambiental , Metais Pesados/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Áreas Alagadas , Bactérias , Biomassa , Chumbo , Poaceae/microbiologia , Rios , Oligoelementos/análise , Typhaceae , Poluição da Água
13.
J Sci Food Agric ; 100(3): 1174-1184, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31696525

RESUMO

BACKGROUND: Appropriate combinations of lactic acid bacteria (LAB) strains should be selected to optimize the ensiling process, and the additives should be adjusted to the ensiled forage crops. The aim of this study was to determine the effect of inoculation with three Lactobacillus species on the chemical parameters and microbiological quality (beneficial and harmful microbiota) of grass silage. RESULTS: Three species: L. paracasei (LPa), L. brevis (LB) and L. plantarum (LPl), isolated from sugar beet silage and characterized based on 16S rDNA sequences and biochemical parameters, were analyzed in the study. Single strains and their combinations were used as silage inoculants. The basic chemical and microbiological (qPCR) parameters of silages were determined. Based on the results of agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) it was determined that silages inoculated with single LAB strains and LPa + LB and commercial additive (0+) were the best quality ones, particularly with regard to microbiological parameters and they effectively lowered the pH value. A consortium of three Lactobacillus species had no influence on silage quality, whereas LPa + LB and LPl + LB combinations as well as a commercial additive exerted positive effects. Inoculation inhibited the growth of toxin-producing fungi. CONCLUSION: Only the appropriate LAB composition can improve the quality of the ensiled material (antagonistic relationship). Only the LPa + LB combination was able to improve the value of low dry silage; nevertheless, almost all combinations were able to reduced concentrations of toxin-producing fungi. © 2019 Society of Chemical Industry.


Assuntos
Ração Animal/microbiologia , Lactobacillus/metabolismo , Poaceae/microbiologia , Silagem/microbiologia , Ração Animal/análise , Beta vulgaris/microbiologia , Fermentação , Aditivos Alimentares/análise , Fungos/genética , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificação , Poaceae/química , Silagem/análise
14.
Plant Dis ; 104(1): 194-197, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31725344

RESUMO

At Point Reyes National Seashore in California, Fusarium circinatum, the causal agent of pitch canker in pines, was isolated from Pinus muricata, the California native grass, Bromus carinatus, and the introduced grass, Holcus lanatus. All grass plants from which F. circinatum was isolated were symptomless. Pathogenicity of grass isolates was confirmed by inoculation of P. radiata trees, which developed symptoms similar to trees inoculated with a pine isolate of F. circinatum. Isolates from grasses were somatically compatible with isolates recovered from symptomatic pines. B. carinatus grown in a growth chamber was inoculated with a green fluorescent protein-expressing strain of F. circinatum. Segments of inoculated leaves were incubated in moist chambers; after 1 to 2 days, sporulating hyphae were observed growing from leaf tissue. Spores of F. circinatum removed from B. carinatus leaves were confirmed to be fluorescent when illuminated with ultraviolet light. These results raise the possibility that B. carinatus cryptically infected by F. circinatum may be a source of propagules capable of infecting pines.


Assuntos
Bromus , Fusarium , Doenças das Plantas , Bromus/microbiologia , California , Fusarium/fisiologia , Pinus/microbiologia , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Esporos Fúngicos
15.
Chemosphere ; 240: 124890, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726588

RESUMO

The presence of diesel in the water could reduce the growth of plant and thus phytoremediation efficacy. The toxicity of diesel to plant is commonly explained; because of hydrocarbons in diesel accumulate in various parts of plants, where they disrupt the plant cell especially, the epidemis, leaves, stem and roots of the plant. This study investigated the effect of bacterial augmentation in floating treatment wetlands (FTWs) on remediation of diesel oil contaminated water. A helophytic plant, Phragmites australis (P. australis), was vegetated on a floating mat to establish FTWs for the remediation of diesel (1%, w/v) contaminated water. The FTWs was inoculated with three bacterial strains (Acinetobacter sp. BRRH61, Bacillus megaterium RGR14 and Acinetobacter iwoffii AKR1), possessing hydrocarbon degradation and plant growth-enhancing capabilities. It was observed that the FTWs efficiently removed hydrocarbons from water, and bacterial inoculation further enhanced its hydrocarbons degradation efficacy. Diesel contaminated water samples collected after fifteen days of time interval for three months and were analyzed for pollution parameters. The maximum reduction in hydrocarbons (95.8%), chemical oxygen demand (98.6%), biochemical oxygen demand (97.7%), total organic carbon (95.2%), phenol (98.9%) and toxicity was examined when both plant and bacteria were employed in combination. Likewise, an increase in plant growth was seen in the presence of bacteria. The inoculated bacteria showed persistence in the water, root and shoot of P. australis. The study concluded that the augmentation of hydrocarbons degrading bacteria in FTWs is a better option for treatment of diesel polluted water.


Assuntos
Inoculantes Agrícolas/crescimento & desenvolvimento , Gasolina/análise , Hidrocarbonetos/análise , Poaceae/microbiologia , Poluentes Químicos da Água/análise , Áreas Alagadas , Acinetobacter/crescimento & desenvolvimento , Bacillus megaterium/crescimento & desenvolvimento , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio
16.
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
17.
Mycologia ; 112(1): 52-63, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31846602

RESUMO

The genus Magnaporthiopsis of Magnaporthaceae (Magnaporthales, Sordariomycetes, Ascomycota) contains species that are predominantly necrotrophic pathogens, often producing simple hyphopodia and dark, ectotrophic runner hyphae on plant roots and stems during colonization. Fungal isolates from turfgrass roots with dark and ectotrophic runner hyphae were examined and identified based on morphological, biological, and phylogenetic analyses. Maximum likelihood and Bayesian methods were implemented to obtain phylogenetic trees for partial sequences of the 18S nuc rDNA, ITS1-5.8S-ITS2 nuc rDNA internal transcribed spacer, and 28S nuc rDNA regions, and of the minichromosome maintenance complex 7 (MCM7), largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-alpha (TEF1) genes. Our isolates consistently formed a distinct and highly supported clade within Magnaporthiopsis. These findings were reinforced by common and distinctive biological and morphological characters. Additionally, we conducted pathogenicity evaluations and demonstrated the ability of this fungus to colonize roots of ultradwarf bermudagrass, one of its native hosts, via ectotrophic, dark runner hyphae, causing disease symptoms including root discoloration and reduced root and shoot mass. Altogether, our discoveries enabled recognition and description of a new species, Magnaporthiopsis cynodontis, which has widespread distribution in the United States.


Assuntos
Ascomicetos/classificação , Ascomicetos/patogenicidade , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Ascomicetos/citologia , Ascomicetos/fisiologia , DNA Fúngico/genética , DNA Ribossômico/genética , Proteínas Fúngicas/genética , Hifas/classificação , Hifas/citologia , Hifas/patogenicidade , Hifas/fisiologia , Filogenia , Raízes de Plantas/microbiologia , RNA Ribossômico/genética , Análise de Sequência de DNA , Estados Unidos
19.
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
20.
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
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