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1.
Braz J Microbiol ; 52(2): 651-661, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33443727

RESUMO

The petrochemical industry is responsible for many accidental releases of pollutants in soil such as hydrocarbons and toxic metals. This co-contamination is responsible for a delay in the degradation of the organic pollution. Many successful technologies to remove these metals apply extracellular polymeric substances (EPS). In this study, we tested the application of an EPS from a Paenibacillus sp. to aid the bioremediation of soils contaminated with crude oil and nickel. We conducted a microcosm experiment to soils containing combinations of oil, nickel, and EPS. The final concentration of oil was evaluated with an infrared spectrometer. Also, we sequenced the metagenomes of the samples in an ion torrent sequencer. The application of EPS did not aid the removal of hydrocarbons with or without the presence of nickel. However, it led to a smaller decrease in the diversity indexes. EPS decreased the abundance of Actinobacteria and increased that of Proteobacteria. The EPS also decreased the connectivity among Actinobacteria in the network analysis. The results indicated that the addition of EPS had a higher effect on the community structure than nickel. Altogether, our results indicate that this approach did not aid the bioremediation of hydrocarbons likely due to its effect in the community structure that affected hydrocarbonoclastic microorganisms.


Assuntos
Bactérias/metabolismo , Biopolímeros/química , Recuperação e Remediação Ambiental/métodos , Níquel/metabolismo , Paenibacillus/química , Microbiologia do Solo , Poluentes do Solo/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Recuperação e Remediação Ambiental/instrumentação , Hidrocarbonetos/metabolismo , Paenibacillus/metabolismo , Petróleo/análise , Petróleo/microbiologia , Solo/química
2.
Arch Microbiol ; 201(8): 1061-1073, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31123792

RESUMO

Plants are colonized by diverse microorganisms that can substantially impact their health and growth. Understanding bacterial diversity and the relationships between bacteria and phytopathogens may be key to finding effective biocontrol agents. We evaluated the bacterial community associated with anthracnose symptomatic and asymptomatic leaves of guarana, a typical tropical crop. Bacterial communities were assessed through culture-independent techniques based on extensive 16S rRNA sequencing, and cultured bacterial strains were evaluated for their ability to inhibit the growth of Colletotrichum sp. as well as for enzyme and siderophore production. The culture-independent method revealed that Proteobacteria was the most abundant phylum, but many sequences were unclassified. The emergence of anthracnose disease did not significantly affect the bacterial community, but the abundance of the genera Acinetobacter, Pseudomonas and Klebsiella were significantly higher in the symptomatic leaves. In vitro growth of Colletotrichum sp. was inhibited by 11.38% of the cultured bacterial strains, and bacteria with the highest inhibition rates were isolated from symptomatic leaves, while asymptomatic leaves hosted significantly more bacteria that produced amylase and polygalacturonase. The bacterial isolate Bacillus sp. EpD2-5 demonstrated the highest inhibition rate against Colletotrichum sp., whereas the isolates EpD2-12 and FD5-12 from the same genus also had high inhibition rates. These isolates were also able to produce several hydrolytic enzymes and siderophores, indicating that they may be good candidates for the biocontrol of anthracnose. Our work demonstrated the importance of using a polyphasic approach to study microbial communities from plant diseases, and future work should focus on elucidating the roles of culture-independent bacterial communities in guarana anthracnose disease.


Assuntos
Antibiose/fisiologia , Agentes de Controle Biológico/isolamento & purificação , Colletotrichum/crescimento & desenvolvimento , Paullinia/microbiologia , Proteobactérias/isolamento & purificação , Acinetobacter/classificação , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Amilases/metabolismo , Antracose/microbiologia , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Klebsiella/classificação , Klebsiella/genética , Klebsiella/isolamento & purificação , Microbiota , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Poligalacturonase/metabolismo , Proteobactérias/classificação , Proteobactérias/genética , Pseudomonas/classificação , Pseudomonas/genética , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Floresta Úmida , Sideróforos/metabolismo
3.
Ecotoxicol Environ Saf ; 179: 232-240, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31051396

RESUMO

Metagenomics is a powerful approach to study microorganisms present in any given environment and their potential to maintain and improve ecosystem health without the need of cultivating these microorganisms in the laboratory. In this study, we combined a cultivation-independent metagenomics approach with functional assays to identify the detoxification potential of microbial genes evaluating their potential to contribute to xenobiotics resistance in oil-impacted mangrove sediments. A metagenomic fosmid library containing 12,960 clones from highly contaminated mangrove sediment was used in this study. For assessment of metal resistance, clones were grown in culture medium with increasing concentrations of mercury. The analyses metagenomic library sequences revealed the presence of genes related to heavy metals and antibiotics resistance in the oil-impacted mangrove microbiome. The taxonomic profiling of these sequences suggests that at the genus level, Geobacter was the most abundant genus in our dataset. A functional screening assessment of the metagenomic library successfully detected 24 potential heavy metal tolerant clones, six of which were capable of growing with increased concentrations of mercury. The genetic characterization of selected clones allowed the detection of genes related to detoxification processes, such as chromate transport protein ChrA, haloacid dehalogenase-like hydrolase, lipopolysaccharide transport system, and 3-oxoacyl-[acyl-carrier-protein] reductase. Clones were capable of growing in medium containing increased concentrations of metals and antibiotics, but none manifested strong mercury removal from culture medium characteristic of mercuric reductase activity. These results suggest that resistance to xenobiotic stress varies greatly and that additional studies to elucidate the potential of metal biotransformation need to be carried out with the goal of improving bioremediation application.


Assuntos
Sedimentos Geológicos , Metagenômica/métodos , Metais Pesados/análise , Microbiota/genética , Áreas Alagadas , Xenobióticos/análise , Biodegradação Ambiental , Resistência Microbiana a Medicamentos/genética , Biblioteca Gênica , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Hidrolases/genética , Metais Pesados/toxicidade , Microbiota/efeitos dos fármacos , Petróleo/análise , Petróleo/toxicidade , Xenobióticos/toxicidade
4.
Sci Rep ; 9(1): 4400, 2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30867512

RESUMO

The world demand for phosphate has gradually increased over the last decades, currently achieving alarming levels considering available rock reserves. The use of soil microorganisms, such as arbuscular mycorrhizal fungi (AMF), has been suggested as a promising alternative to improve phosphorus-use efficiency. However, the effect of the source of phosphorus on the interactions within the soil microbial community remains unclear. Here, we evaluated the links between the total dry matter content of sugarcane and the interactions within the soil microbial community under different phosphate sources, with/without AMF inoculation. The phosphate sources were Simple Superphosphate (SS, 18% of P2O5), Catalão rock phosphate (CA, 2.93% of P2O5) and Bayovar rock phosphate (BA, 14% of P2O5). The results indicated that the BA source led to the largest total dry matter content. The phosphate source affected total dry matter and the structure of the soil microbial communities. The bacterial interactions increased across sources with high percentage of P2O5, while the fungal interactions decreased. The interactions between bacterial and fungal microorganisms allowed to identify the percentage of P2O5 resulting in the highest total sugarcane dry matter. Our findings suggested the soil microbial interactions as a potential microbial indicator helping to improve the agricultural management.


Assuntos
Fósforo/química , Saccharum/crescimento & desenvolvimento , Saccharum/microbiologia , Difosfatos/química , Solo/química , Microbiologia do Solo
5.
J Anim Physiol Anim Nutr (Berl) ; 103(1): 72-86, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30485573

RESUMO

The purpose of this study was to verify the ability of a probiotic in the feed to maintain the stability of the gut microbiota in chickens after antibiotic therapy and its association with growth performance. One thousand six hundred twenty 1-day-old Cobb male were housed in floor pens (36 pens, 45 birds/pen) and were fed corn-/soya bean meal-based diets supplemented with or without probiotic (Bacillus subtilis) during the entire rearing phase. From 21 to 24 days of age (three consecutive days), the chickens were submitted to antibiotic therapy via drinking water (bacitracin and neomycin) in order to mimic a field treatment and induce dysbiosis. Growth performance was monitored until 42 days of age. At 2, 4 and 6 days after antibiotic therapy, three chickens from each pen were euthanized and the contents of the small intestine and caeca were collected and pooled. The trial was conducted with four treatments and nine replicates in a 2 × 2 factorial arrangement for performance characteristics (with and without probiotic × with and without antibiotic therapy); for the intestinal microbiota, it was in a 2 × 2 × 3 factorial arrangement (with and without probiotic × with and without antibiotic therapy × 2, 4 and 6 days after the antibiotic therapy) with three replicates per treatment. Terminal restriction length polymorphism (T-RFLP) analysis showed that the structure of gut bacterial community was shaped by the intestinal segment and by the time after the antibiotic therapy. The number of 16S rDNAs copies in caecum contents decreased with time after the therapeutic treatment. The antibiotic therapy and dietary probiotic supplementation decreased richness and diversity indexes in the caecal contents. The improved performance observed in birds supplemented with probiotic may be related to changes promoted by the feed additive in the structure of the intestinal bacterial communities and phylogenetic groups. Antibiotic therapy modified the bacterial structure, but did not cause loss of broiler performance.


Assuntos
Ração Animal/análise , Bacitracina/farmacologia , Galinhas/crescimento & desenvolvimento , Microbioma Gastrointestinal/efeitos dos fármacos , Neomicina/farmacologia , Probióticos/farmacologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Bacitracina/administração & dosagem , Galinhas/microbiologia , Dieta/veterinária , Neomicina/administração & dosagem , Distribuição Aleatória
6.
Braz. j. microbiol ; Braz. j. microbiol;49(1): 87-96, Jan.-Mar. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-889214

RESUMO

ABSTRACT Variations in microbial communities promoted by alterations in environmental conditions are reflected in similarities/differences both at taxonomic and functional levels. Here we used a natural gradient within mangroves from seashore to upland, to contrast the natural variability in bacteria, cyanobacteria and diazotroph assemblages in a pristine area compared to an oil polluted area along a timespan of three years, based on ARISA (bacteria and cyanobacteria) and nifH T-RFLP (diazotrophs) fingerprinting. The data presented herein indicated that changes in all the communities evaluated were mainly driven by the temporal effect in the contaminated area, while local effects were dominant on the pristine mangrove. A positive correlation of community structure between diazotrophs and cyanobacteria was observed, suggesting the functional importance of this phylum as nitrogen fixers in mangroves soils. Different ecological patterns explained the microbial behavior in the pristine and polluted mangroves. Stochastic models in the pristine mangrove indicate that there is not a specific environmental factor that determines the bacterial distribution, while cyanobacteria and diazotrophs better fitted in deterministic model in the same area. For the contaminated mangrove site, deterministic models better represented the variations in the communities, suggesting that the presence of oil might change the microbial ecological structures over time. Mangroves represent a unique environment threatened by global change, and this study contributed to the knowledge of the microbial distribution in such areas and its response on persistent contamination historic events.


Assuntos
Solo/química , Microbiologia do Solo , Bactérias/isolamento & purificação , Filogenia , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Petróleo/análise , Petróleo/metabolismo , Biodiversidade , Áreas Alagadas , Nitrogênio/metabolismo
7.
Braz J Microbiol ; 49(1): 87-96, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28827029

RESUMO

Variations in microbial communities promoted by alterations in environmental conditions are reflected in similarities/differences both at taxonomic and functional levels. Here we used a natural gradient within mangroves from seashore to upland, to contrast the natural variability in bacteria, cyanobacteria and diazotroph assemblages in a pristine area compared to an oil polluted area along a timespan of three years, based on ARISA (bacteria and cyanobacteria) and nifH T-RFLP (diazotrophs) fingerprinting. The data presented herein indicated that changes in all the communities evaluated were mainly driven by the temporal effect in the contaminated area, while local effects were dominant on the pristine mangrove. A positive correlation of community structure between diazotrophs and cyanobacteria was observed, suggesting the functional importance of this phylum as nitrogen fixers in mangroves soils. Different ecological patterns explained the microbial behavior in the pristine and polluted mangroves. Stochastic models in the pristine mangrove indicate that there is not a specific environmental factor that determines the bacterial distribution, while cyanobacteria and diazotrophs better fitted in deterministic model in the same area. For the contaminated mangrove site, deterministic models better represented the variations in the communities, suggesting that the presence of oil might change the microbial ecological structures over time. Mangroves represent a unique environment threatened by global change, and this study contributed to the knowledge of the microbial distribution in such areas and its response on persistent contamination historic events.


Assuntos
Bactérias/isolamento & purificação , Microbiologia do Solo , Solo/química , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Biodiversidade , Nitrogênio/metabolismo , Petróleo/análise , Petróleo/metabolismo , Filogenia , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Áreas Alagadas
8.
Environ Pollut ; 216: 460-469, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27297401

RESUMO

Mangroves are complex and dynamic ecosystems highly dependent on diverse microbial activities. In the last decades, these ecosystems have been exposed to and affected by diverse human activities, such as waste disposal and accidental oil spills. Complex microbial communities inhabiting the soil and sediment of mangroves comprise microorganisms that have developed mechanisms to adapt to organic and inorganic contaminants. The resistance of these microbes to contaminants is an attractive property and also the reason why soil and sediment living microorganisms and their enzymes have been considered promising for environmental detoxification. The aim of the present study was to identify active microbial genes in heavy metals, i.e., Cu, Zn, Cd, Pb and Hg, and antibiotic resistomes of polluted and pristine mangrove sediments through the comparative analysis of metatranscriptome data. The concentration of the heavy metals Zn, Cr, Pb, Cu, Ni, Cd, and Hg and abundance of genes and transcripts involved in resistance to toxic compounds (the cobalt-zinc-cadmium resistance protein complex; the cobalt-zinc-cadmium resistance protein CzcA and the cation efflux system protein CusA) have been closely associated with sites impacted with petroleum, sludge and other urban waste. The taxonomic profiling of metatranscriptome sequences suggests that members of Gammaproteobacteria and Deltaproteobacteria classes contribute to the detoxification of the polluted soil. Desulfobacterium autotrophicum was the most abundant microorganism in the oil-impacted site and displayed specific functions related to heavy metal resistance, potentially playing a key role in the successful persistence of the microbial community of this site.


Assuntos
Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos , Sedimentos Geológicos/química , Metais Pesados/farmacologia , Poluentes do Solo/análise , Áreas Alagadas , Antibacterianos/análise , Cádmio/análise , Ecossistema , Monitoramento Ambiental , Humanos , Mercúrio/análise , Metais Pesados/análise , Petróleo/análise , Esgotos/análise , Microbiologia do Solo , Microbiologia da Água
9.
Microb Ecol ; 67(2): 237-41, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24173537

RESUMO

The Brazilian Microbiome Project (BMP) aims to assemble a Brazilian Metagenomic Consortium/Database. At present, many metagenomic projects underway in Brazil are widely known. Our goal in this initiative is to co-ordinate and standardize these together with new projects to come. It is estimated that Brazil hosts approximately 20 % of the entire world's macroorganism biological diversity. It is 1 of the 17 countries that share nearly 70 % of the world's catalogued animal and plant species, and is recognized as one of the most megadiverse countries. At the end of 2012, Brazil has joined GBIF (Global Biodiversity Information Facility), as associated member, to improve the access to the Brazilian biodiversity data in a free and open way. This was an important step toward increasing international collaboration and clearly shows the commitment of the Brazilian government in directing national policies toward sustainable development. Despite its importance, the Brazilian microbial diversity is still considered to be largely unknown, and it is clear that to maintain ecosystem dynamics and to sustainably manage land use, it is crucial to understand the biological and functional diversity of the system. This is the first attempt to collect and collate information about Brazilian microbial genetic and functional diversity in a systematic and holistic manner. The success of the BMP depends on a massive collaborative effort of both the Brazilian and international scientific communities, and therefore, we invite all colleagues to participate in this project.


Assuntos
Comitês Consultivos/organização & administração , Biodiversidade , Metagenoma , Microbiota , Animais , Brasil , Bases de Dados Factuais , Plantas/microbiologia , Microbiologia do Solo
10.
Braz. j. microbiol ; Braz. j. microbiol;44(4): 1331-1339, Oct.-Dec. 2013. graf, tab
Artigo em Inglês | LILACS | ID: lil-705276

RESUMO

Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and methanol), respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones) and plant exudates (including ethanol) in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF), adaptation to stressful environment (crtI, phoU and sss), to interactions with plant metabolism compounds (acdS) and pathogenicity (patatin and phoU). Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization), which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.


Assuntos
Acil-Butirolactonas/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Interações Hospedeiro-Parasita , Methylobacterium/fisiologia , Extratos Vegetais/metabolismo , Plantas/microbiologia , Methylobacterium/crescimento & desenvolvimento
11.
PLoS One ; 8(7): e67948, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23844136

RESUMO

BACKGROUND: In this study, we assessed the actively metabolizing bacteria in the rhizosphere of potato using two potato cultivars, i.e. the genetically-modified (GM) cultivar Modena (having tubers with altered starch content) and the near-isogenic non-GM cultivar Karnico. To achieve our aims, we pulse-labelled plants at EC90 stage with (13)C-CO2 and analysed their rhizosphere microbial communities 24 h, 5 and 12 days following the pulse. In the analyses, phospholipid fatty acid/stable isotope probing (PLFA-SIP) as well as RNA-SIP followed by reverse transcription and PCR-DGGE and clone library analysis, were used to determine the bacterial groups that actively respond to the root-released (13)C labelled carbonaceous compounds. METHODOLOGY/PRINCIPAL FINDINGS: The PLFA-SIP data revealed major roles of bacteria in the uptake of root-released (13)C carbon, which grossly increased with time. Gram-negative bacteria, including members of the genera Pseudomonas and Burkholderia, were strong accumulators of the (13)C-labeled compounds at the two cultivars, whereas Gram-positive bacteria were lesser responders. PCR-DGGE analysis of cDNA produced from the two cultivar types showed that these had selected different bacterial, alpha- and betaproteobacterial communities at all time points. Moreover, an effect of time was observed, indicating dynamism in the structure of the active bacterial communities. PCR-DGGE as well as clone library analyses revealed that the main bacterial responders at cultivar Karnico were taxonomically affiliated with the genus Pseudomonas, next to Gluconacetobacter and Paracoccus. Cultivar Modena mainly attracted Burkholderia, next to Moraxella-like (Moraxellaceae family) and Sphingomonas types. CONCLUSIONS/SIGNIFICANCE: Based on the use of Pseudomonas and Burkholderia as proxies for differentially-selected bacterial genera, we conclude that the selective forces exerted by potato cultivar Modena on the active bacterial populations differed from those exerted by cultivar Karnico.


Assuntos
Bactérias/genética , Bactérias/metabolismo , Rizosfera , Solanum tuberosum/microbiologia , Bactérias/classificação , Biodiversidade , Biomarcadores/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Metagenoma , Microbiota , Fenótipo , Fosfolipídeos/química , Fosfolipídeos/metabolismo , Filogenia , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Microbiologia do Solo , Solanum tuberosum/genética , Solanum tuberosum/crescimento & desenvolvimento
12.
Braz J Microbiol ; 44(4): 1331-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24688531

RESUMO

Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and methanol), respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones) and plant exudates (including ethanol) in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF), adaptation to stressful environment (crtI, phoU and sss), to interactions with plant metabolism compounds (acdS) and pathogenicity (patatin and phoU). Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization), which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.


Assuntos
Acil-Butirolactonas/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Interações Hospedeiro-Parasita , Methylobacterium/fisiologia , Extratos Vegetais/metabolismo , Plantas/microbiologia , Methylobacterium/crescimento & desenvolvimento
13.
Antonie Van Leeuwenhoek ; 97(4): 389-99, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20352404

RESUMO

Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is believed that specific bacterial functions are required for plant colonization, but also from the plant side specific features are needed, such as plant genotype (cultivar) and developmental stage. Via multivariate analysis we present a quantification of the roles of these components on the composition of root-associated and endophytic bacterial communities in potato plants, by weighing the effects of bacterial inoculation, plant genotype and developmental stage. Spontaneous rifampicin resistant mutants of two bacterial endophytes, Paenibacillus sp. strain E119 and Methylobacterium mesophilicum strain SR1.6/6, were introduced into potato plants of three different cultivars (Eersteling, Robijn and Karnico). Densities of both strains in, or attached to potato plants were measured by selective plating, while the effects of bacterial inoculation, plant genotype and developmental stage on the composition of bacterial, Alphaproteobacterial and Paenibacillus species were determined by PCR-denaturing gradient gel-electrophoresis (DGGE). Multivariate analyses revealed that the composition of bacterial communities was mainly driven by cultivar type and plant developmental stage, while Alphaproteobacterial and Paenibacillus communities were mainly influenced by bacterial inoculation. These results are important for better understanding the effects of bacterial inoculations to plants and their possible effects on the indigenous bacterial communities in relation with other plant factors such as genotype and growth stage.


Assuntos
Biodiversidade , Methylobacterium/fisiologia , Paenibacillus/fisiologia , Raízes de Plantas/microbiologia , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/microbiologia , Simbiose , Contagem de Colônia Microbiana , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Poliacrilamida , Genótipo , Methylobacterium/classificação , Methylobacterium/crescimento & desenvolvimento , Dados de Sequência Molecular , Desnaturação de Ácido Nucleico , Paenibacillus/classificação , Paenibacillus/crescimento & desenvolvimento , Análise de Sequência de DNA , Solanum tuberosum/genética
14.
Appl Environ Microbiol ; 75(11): 3396-406, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19329656

RESUMO

Pseudomonas putida strain P9 is a novel competent endophyte from potato. P9 causes cultivar-dependent suppression of Phytophthora infestans. Colonization of the rhizoplane and endosphere of potato plants by P9 and its rifampin-resistant derivative P9R was studied. The purposes of this work were to follow the fate of P9 inside growing potato plants and to establish its effect on associated microbial communities. The effects of P9 and P9R inoculation were studied in two separate experiments. The roots of transplants of three different cultivars of potato were dipped in suspensions of P9 or P9R cells, and the plants were planted in soil. The fate of both strains was followed by examining colony growth and by performing PCR-denaturing gradient gel electrophoresis (PCR-DGGE). Colonies of both strains were recovered from rhizoplane and endosphere samples of all three cultivars at two growth stages. A conspicuous band, representing P9 and P9R, was found in all Pseudomonas PCR-DGGE fingerprints for treated plants. The numbers of P9R CFU and the P9R-specific band intensities for the different replicate samples were positively correlated, as determined by linear regression analysis. The effects of plant growth stage, genotype, and the presence of P9R on associated microbial communities were examined by multivariate and unweighted-pair group method with arithmetic mean cluster analyses of PCR-DGGE fingerprints. The presence of strain P9R had an effect on bacterial groups identified as Pseudomonas azotoformans, Pseudomonas veronii, and Pseudomonas syringae. In conclusion, strain P9 is an avid colonizer of potato plants, competing with microbial populations indigenous to the potato phytosphere. Bacterization with a biocontrol agent has an important and previously unexplored effect on plant-associated communities.


Assuntos
Antibiose , Pseudomonas putida/classificação , Pseudomonas putida/isolamento & purificação , Solanum tuberosum/microbiologia , Simbiose , Biodiversidade , Análise por Conglomerados , Contagem de Colônia Microbiana , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Desnaturação de Ácido Nucleico , Filogenia , Raízes de Plantas/microbiologia , Pseudomonas putida/fisiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico
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