RESUMO
Here we analyze the microbial community of healthy and diseased tomato plants to evaluate its impact on plant health. The organisms found in all samples mainly belonged to 4 phyla: Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The Proteobacteria were the highest relative abundant within the endophytic communities of different plant organs of diseased tomato. Among endophytic bacteria of tomato, only a few taxa could be cultured. Here we showed that only a few taxa of bacteria inhabiting tomato plants could be cultured and that all plant organs have a highly diverse endophytic bacterial, whose activity might affect plant growth and development as well as health. The roots seem to be an important barrier for microbes and leaves appear to be the organs with the higher diversity which is incidentally related to plant health. Fruits also contain a complex bacterial community that appeared to be unaffected by foliar diseases such as gray leaf spot at least under the conditions studied.
Assuntos
Fenômenos Fisiológicos Bacterianos , Microbiota/fisiologia , Doenças das Plantas/microbiologia , Solanum lycopersicum/microbiologia , Actinobacteria/fisiologia , Bactérias/classificação , Bacteroidetes/fisiologia , Endófitos/classificação , Firmicutes/fisiologia , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Proteobactérias/fisiologiaRESUMO
The white leg Litopenaeus vannamei shrimp is of importance to the eastern Pacific fisheries and aquaculture industry but suffer from diseases such as the recently emerged early mortality syndrome. Many bacterial pathogens have been identified but the L. vannamei microbiota is still poorly known. Using a next-generation sequencing (NGS) approach, this work evaluated the impact of the inclusion in the diet of mannan oligosaccharide, (MOS, 0.5% w/w), over the L. vannamei microbiota and production behavior of L. vannamei under intensive cultivation in Ecuador. The MOS supplementation lasted for 60 days, after which the shrimp in the ponds were harvested, and the production data were collected. MOS improved productivity outcomes by increasing shrimp survival by 30%. NGS revealed quantitative differences in the shrimp microbiota between MOS and control conditions. In the treatment with inclusion of dietary MOS, the predominant phylum was Actinobacteria (28%); while the control group was dominated by the phylum Proteobacteria (30%). MOS has also been linked to an increased prevalence of Lactococcus- and Verrucomicrobiaceae-like bacteria. Furthermore, under the treatment of MOS, the prevalence of potential opportunistic pathogens, like Vibrio, Aeromonas, Bergeyella and Shewanella, was negligible. This may be attributable to MOS blocking the adhesion of pathogens to the surfaces of the host tissues. Together, these findings point to the fact that the performance (survival) improvements of the dietary MOS may be linked to the impact on the microbiota, since bacterial lines with pathogenic potential towards shrimps were excluded in the gut.
Assuntos
Actinobacteria/fisiologia , Aquicultura/métodos , Mananas/administração & dosagem , Microbiota , Oligossacarídeos/administração & dosagem , Penaeidae/microbiologia , Actinobacteria/classificação , Actinobacteria/isolamento & purificação , Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Ração Animal , Animais , Aderência Bacteriana , Equador , Flavobacteriaceae/isolamento & purificação , Flavobacteriaceae/patogenicidade , Lactococcus/isolamento & purificação , Lactococcus/fisiologia , Longevidade/fisiologia , Proteobactérias/classificação , Proteobactérias/isolamento & purificação , Proteobactérias/fisiologia , Alimentos Marinhos/microbiologia , Alimentos Marinhos/provisão & distribuição , Shewanella/isolamento & purificação , Shewanella/patogenicidade , Verrucomicrobia/classificação , Verrucomicrobia/isolamento & purificação , Verrucomicrobia/fisiologia , Vibrio/isolamento & purificação , Vibrio/patogenicidadeRESUMO
Vigna is a genus of legumes cultivated in specific areas of tropical countries. Species in this genus are important crops worldwide. Vigna species are of great agronomic interest in Venezuela because Vigna beans are an excellent alternative to other legumes. However, this type of crop has some cultivation issues due to sensitivity to acidic soils, high temperatures, and salinity stress, which are common in Venezuela. Vigna species establish symbioses mainly with Bradyrhizobium and Ensifer, and Vigna-rhizobia interactions have been examined in Asia, Africa, and America. However, the identities of the rhizobia associated with V. radiata and V. unguiculata in Venezuela remain unknown. In the present study, we isolated Venezuelan symbiotic rhizobia associated with Vigna species from soils with contrasting agroecosystems or from fields in Venezuela. Several types of soils were used for bacterial isolation and nodules were sampled from environments characterized by abiotic stressors, such as high temperatures, high concentrations of NaCl, and acidic or alkaline pH. Venezuelan Vigna-rhizobia were mainly fast-growing. Sequencing of several housekeeping genes showed that in contrast to other continents, Venezuelan Vigna species were nodulated by rhizobia genus including Burkholderia, containing bacteria from several new phylogenetic lineages within the genus Bradyrhizobium. Some Rhizobium and Bradyrhizobium isolates were tolerant of high salinity and Al toxicity. The stress tolerance of strains was dependent on the type of rhizobia, soil origin, and cultivation history. An isolate classified as R. phaseoli showed the highest plant biomass, nitrogen fixation, and excellent abiotic stress response, suggesting a novel promising inoculant for Vigna cultivation in Venezuela.
Assuntos
Filogenia , Proteobactérias/classificação , Proteobactérias/fisiologia , Microbiologia do Solo , Simbiose , Vigna/microbiologia , DNA Bacteriano/genética , Genes Bacterianos/genética , Fixação de Nitrogênio/genética , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Nódulos Radiculares de Plantas/microbiologia , Análise de Sequência de DNA , Solo/química , Estresse Fisiológico , Venezuela , Vigna/crescimento & desenvolvimentoRESUMO
Cyclic ß-1,2-D-glucans (CßG) are natural bionanopolymers present in the periplasmic space of many Proteobacteria. These molecules are sugar rings made of 17 to 25 D-glucose units linked exclusively by ß-1,2-glycosidic bonds. CßG are important for environmental sensing and osmoadaptation in bacteria, but most importantly, they play key roles in complex host-cell interactions such as symbiosis, pathogenesis, and immunomodulation. In the last years, the identification and characterisation of the enzymes involved in the synthesis of CßG allowed to know in detail the steps necessary for the formation of these sugar rings. Due to its peculiar structure, CßG can complex large hydrophobic molecules, a feature possibly related to its function in the interaction with the host. The capabilities of the CßG to function as molecular boxes and to solubilise hydrophobic compounds are attractive for application in the development of drugs, in food industry, nanotechnology, and chemistry. More importantly, its excellent immunomodulatory properties led to the proposal of CßG as a new class of adjuvants for vaccine development.
Assuntos
Interações Hospedeiro-Patógeno , Proteobactérias/fisiologia , Proteobactérias/patogenicidade , Simbiose , beta-Glucanas/química , beta-Glucanas/metabolismo , Vias Biossintéticas , Interações Hidrofóbicas e HidrofílicasRESUMO
Biodegradation of phenolic compounds in bioreactors is well documented, but the changes in the bacterial populations dynamics during degradation were not that often. A glass bubble column used as reactor was inoculated with activated sludge, spiked with 2-chlorophenol, phenol and m-cresol after 28 days and maintained for an additional 56 days, while the 16S rRNA gene from metagenomic DNA was monitored. Proteobacteria (68.1%) dominated the inoculum, but the bacterial composition changed rapidly. The relative abundance of Bacteroidetes and Firmicutes decreased from 4.8 and 9.4 to <0.1 and 0.2% respectively, while that of Actinobacteria and TM7 increased from 4.8 and 2.0 to 19.2 and 16.1% respectively. Phenol application increased the relative abundance of Proteobacteria to 94.2% (mostly Brevundimonas 17.6%), while that of Bacteroidetes remained low (1.2%) until day 42. It then increased to 47.3% (mostly Leadbetterella 46.9%) at day 84. It was found that addition of phenolic compounds did not affect the relative abundance of the Alphaproteobacteria initially, but it decreased slowly while that of the Bacteroidetes increased towards the end.
Assuntos
Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Biodegradação Ambiental , Reatores Biológicos , Consórcios Microbianos/efeitos dos fármacos , Fenóis/metabolismo , Fenóis/farmacologia , Esgotos/microbiologia , Actinobacteria/classificação , Actinobacteria/efeitos dos fármacos , Actinobacteria/genética , Actinobacteria/fisiologia , Bactérias/classificação , Bactérias/genética , Bacteroidetes/classificação , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/genética , Bacteroidetes/fisiologia , Clorofenóis/metabolismo , Clorofenóis/farmacologia , Cresóis/metabolismo , Cresóis/farmacologia , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica , Consórcios Microbianos/genética , Consórcios Microbianos/fisiologia , Fenol/metabolismo , Fenol/farmacologia , Proteobactérias/classificação , Proteobactérias/efeitos dos fármacos , Proteobactérias/genética , Proteobactérias/fisiologia , RNA Ribossômico 16S , Esgotos/análiseRESUMO
Abstract The development of showerhead biofilms exposes the user to repeated contact with potentially pathogenic microbes, yet we know relatively little about the content of these aggregates. The aim of the present study was to examine the microbial content of tape-like films found protruding from a domestic showerhead. Culturing showed that the films were dominated by aerobic α- and β-proteobacteria. Three isolates made up almost the entire plate count. These were a Brevundimonas species, a metalophilic Cupriavidus species and a thermophile, Geobacillus species. Furthermore, it was shown that the Cupriavidus isolate alone had a high capacity for biofilm formation and thus might be the initiator of biofilm production. A clone library revealed the same general composition. However, half of the 70 clones analyzed could not be assigned to a particular bacterial phylum and of these 29 differed from one another by only 1–2 base pairs, indicating a single species. Thus both the culture dependent and culture independent characterizations suggest a simple yet novel composition. The work is important as the biofilm is fundamentally different in form (tape-like) and content from that of all previously reported ones, where variously Mycobacterium, Methylobacterium and Xanthomonas species have dominated, and extremophiles were not reported.
Assuntos
Biofilmes , Proteobactérias/isolamento & purificação , Proteobactérias/fisiologia , Coloração e Rotulagem , DNA Bacteriano/genética , RNA Ribossômico 16S/genética , Proteobactérias/genética , Proteobactérias/químicaRESUMO
The development of showerhead biofilms exposes the user to repeated contact with potentially pathogenic microbes, yet we know relatively little about the content of these aggregates. The aim of the present study was to examine the microbial content of tape-like films found protruding from a domestic showerhead. Culturing showed that the films were dominated by aerobic α- and ß-proteobacteria. Three isolates made up almost the entire plate count. These were a Brevundimonas species, a metalophilic Cupriavidus species and a thermophile, Geobacillus species. Furthermore, it was shown that the Cupriavidus isolate alone had a high capacity for biofilm formation and thus might be the initiator of biofilm production. A clone library revealed the same general composition. However, half of the 70 clones analyzed could not be assigned to a particular bacterial phylum and of these 29 differed from one another by only 1-2 base pairs, indicating a single species. Thus both the culture dependent and culture independent characterizations suggest a simple yet novel composition. The work is important as the biofilm is fundamentally different in form (tape-like) and content from that of all previously reported ones, where variously Mycobacterium, Methylobacterium and Xanthomonas species have dominated, and extremophiles were not reported.
Assuntos
Biofilmes , Proteobactérias/isolamento & purificação , Proteobactérias/fisiologia , DNA Bacteriano/genética , Proteobactérias/química , Proteobactérias/genética , RNA Ribossômico 16S/genética , Coloração e RotulagemRESUMO
Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, ß, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region.
Assuntos
Endófitos/genética , Fusarium/genética , Fusarium/isolamento & purificação , Piper/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , DNA Ribossômico/genética , Firmicutes/fisiologia , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Filogenia , Doenças das Plantas/genética , Proteobactérias/fisiologia , Pseudomonas/fisiologiaRESUMO
BACKGROUND: Marine invertebrate-associated microbial communities are interesting examples of complex symbiotic systems and are a potential source of biotechnological products. RESULTS: In this work, pyrosequencing-based assessment from bacterial community structures of sediments, two sponges, and one zoanthid collected in the Mexican Caribbean was performed. The results suggest that the bacterial diversity at the species level is higher in the sediments than in the animal samples. Analysis of bacterial communities' structure showed that about two thirds of the bacterial diversity in all the samples belongs to the phyla Acidobacteria and Proteobacteria. The genus Acidobacterium appears to dominate the bacterial community in all the samples, reaching almost 80% in the sponge Hyrtios. CONCLUSIONS: Our evidence suggests that the sympatric location of these benthonic species may lead to common bacterial structure features among their bacterial communities. The results may serve as a first insight to formulate hypotheses that lead to more extensive studies of sessile marine organisms' microbiomes from the Mexican Caribbean.
Assuntos
Acidobacteria/fisiologia , Antozoários/microbiologia , Microbiota/fisiologia , Poríferos/microbiologia , Simpatria , Animais , Antozoários/classificação , Biodiversidade , Região do Caribe , Sedimentos Geológicos/microbiologia , México , Filogenia , Poríferos/classificação , Proteobactérias/classificação , Proteobactérias/fisiologia , RNA Ribossômico 16S/análise , Simbiose/fisiologiaRESUMO
BACKGROUND: Marine invertebrate-associated microbial communities are interesting examples of complex symbiotic systems and are a potential source of biotechnological products. RESULTS: In this work, pyrosequencing-based assessment from bacterial community structures of sediments, two sponges, and one zoanthid collected in the Mexican Caribbean was performed. The results suggest that the bacterial diversity at the species level is higher in the sediments than in the animal samples. Analysis of bacterial communities' structure showed that about two thirds of the bacterial diversity in all the samples belongs to the phyla Acidobacteria and Proteobacteria. The genus Acidobacteriumappears to dominate the bacterial community in all the samples, reaching almost 80% in the sponge Hyrtios. CONCLUSIONS: Our evidence suggests that the sympatric location of these benthonic species may lead to common bacterial structure features among their bacterial communities. The results may serve as a first insight to formulate hypotheses that lead to more extensive studies of sessile marine organisms' microbiomes from the Mexican Caribbean.